binary gravitational microlensing: Topics by Science.gov

Sample records for binary gravitational microlensing

Gravitational Microlensing Events as a Target for the SETI project

NASA Astrophysics Data System (ADS)

Rahvar, Sohrab

2016-09-01

The detection of signals from a possible extrasolar technological civilization is one of the most challenging efforts of science. In this work, we propose using natural telescopes made of single or binary gravitational lensing systems to magnify leakage of electromagnetic signals from a remote planet that harbors Extraterrestrial Intelligent (ETI) technology. Currently, gravitational microlensing surveys are monitoring a large area of the Galactic bulge to search for microlensing events, finding more than 2000 events per year. These lenses are capable of playing the role of natural telescopes, and, in some instances, they can magnify radio band signals from planets orbiting around the source stars in gravitational microlensing systems. Assuming that the frequency of electromagnetic waves used for telecommunication in ETIs is similar to ours, we propose follow-up observation of microlensing events with radio telescopes such as the Square Kilometre Array (SKA), the Low Frequency Demonstrators, and the Mileura Wide-Field Array. Amplifying signals from the leakage of broadcasting by an Earth-like civilization will allow us to detect them as far as the center of the Milky Way galaxy. Our analysis shows that in binary microlensing systems, the probability of amplification of signals from ETIs is more than that in single microlensing events. Finally, we propose the use of the target of opportunity mode for follow-up observations of binary microlensing events with SKA as a new observational program for searching ETIs. Using optimistic values for the factors of the Drake equation provides detection of about one event per year.
GRAVITATIONAL MICROLENSING EVENTS AS A TARGET FOR THE SETI PROJECT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahvar, Sohrab, E-mail: rahvar@sharif.edu

2016-09-01

The detection of signals from a possible extrasolar technological civilization is one of the most challenging efforts of science. In this work, we propose using natural telescopes made of single or binary gravitational lensing systems to magnify leakage of electromagnetic signals from a remote planet that harbors Extraterrestrial Intelligent (ETI) technology. Currently, gravitational microlensing surveys are monitoring a large area of the Galactic bulge to search for microlensing events, finding more than 2000 events per year. These lenses are capable of playing the role of natural telescopes, and, in some instances, they can magnify radio band signals from planets orbitingmore » around the source stars in gravitational microlensing systems. Assuming that the frequency of electromagnetic waves used for telecommunication in ETIs is similar to ours, we propose follow-up observation of microlensing events with radio telescopes such as the Square Kilometre Array (SKA), the Low Frequency Demonstrators, and the Mileura Wide-Field Array. Amplifying signals from the leakage of broadcasting by an Earth-like civilization will allow us to detect them as far as the center of the Milky Way galaxy. Our analysis shows that in binary microlensing systems, the probability of amplification of signals from ETIs is more than that in single microlensing events. Finally, we propose the use of the target of opportunity mode for follow-up observations of binary microlensing events with SKA as a new observational program for searching ETIs. Using optimistic values for the factors of the Drake equation provides detection of about one event per year.« less
PARALLAX AND ORBITAL EFFECTS IN ASTROMETRIC MICROLENSING WITH BINARY SOURCES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nucita, A. A.; Paolis, F. De; Ingrosso, G.

2016-06-01

In gravitational microlensing, binary systems may act as lenses or sources. Identifying lens binarity is generally easy, in particular in events characterized by caustic crossing since the resulting light curve exhibits strong deviations from a smooth single-lensing light curve. In contrast, light curves with minor deviations from a Paczyński behavior do not allow one to identify the source binarity. A consequence of gravitational microlensing is the shift of the position of the multiple image centroid with respect to the source star location — the so-called astrometric microlensing signal. When the astrometric signal is considered, the presence of a binary sourcemore » manifests with a path that largely differs from that expected for single source events. Here, we investigate the astrometric signatures of binary sources taking into account their orbital motion and the parallax effect due to the Earth’s motion, which turn out not to be negligible in most cases. We also show that considering the above-mentioned effects is important in the analysis of astrometric data in order to correctly estimate the lens-event parameters.« less
Gravitational microlensing by double stars and planetary systems

NASA Technical Reports Server (NTRS)

Mao, Shunde; Paczynski, Bohdan

1991-01-01

Almost all stars are in binary systems. When the separation between the two components is comparable to the Einstein ring radius corresponding to the combined mass of the binary acting as a gravitational lens, then an extra pair of images can be created, and the light curve of a lensed source becomes complicated. It is estimated that about 10 percent of all lensing episodes of the Galactic bulge stars will strongly display the binary nature of the lens. The effect is strong even if the companion is a planet. A massive search for microlensing of the Galactic bulge stars may lead to a discovery of the first extrasolar planetary systems.
OGLE-2017-BLG-1130: The First Binary Gravitational Microlens Detected from Spitzer Only

NASA Astrophysics Data System (ADS)

Wang, Tianshu; Calchi Novati, S.; Udalski, A.; Gould, A.; Mao, Shude; Zang, W.; Beichman, C.; Bryden, G.; Carey, S.; Gaudi, B. S.; Henderson, C. B.; Shvartzvald, Y.; Yee, J. C.; Spitzer Team; Mróz, P.; Poleski, R.; Skowron, J.; Szymański, M. K.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Pawlak, M.; OGLE Collaboration; Albrow, M. D.; Chung, S.-J.; Han, C.; Hwang, K.-H.; Jung, Y. K.; Ryu, Y.-H.; Shin, I.-G.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.; KMTNet Collaboration

2018-06-01

We analyze the binary gravitational microlensing event OGLE-2017-BLG-1130 (mass ratio q ∼ 0.45), the first published case in which the binary anomaly was detected only by the Spitzer Space Telescope. This event provides strong evidence that some binary signals can be missed by observations from the ground alone but detected by Spitzer. We therefore invert the normal procedure, first finding the lens parameters by fitting the space-based data and then measuring the microlensing parallax using ground-based observations. We also show that the normal four-fold space-based degeneracy in the single-lens case can become a weak eight-fold degeneracy in binary-lens events. Although this degeneracy is resolved in event OGLE-2017-BLG-1130, it might persist in other events.
BINARY ASTROMETRIC MICROLENSING WITH GAIA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sajadian, Sedighe, E-mail: sajadian@ipm.ir; Department of Physics, Sharif University of Technology, P.O. Box 11155-9161, Tehran

2015-04-15

We investigate whether or not Gaia can specify the binary fractions of massive stellar populations in the Galactic disk through astrometric microlensing. Furthermore, we study whether or not some information about their mass distributions can be inferred via this method. In this regard, we simulate the binary astrometric microlensing events due to massive stellar populations according to the Gaia observing strategy by considering (i) stellar-mass black holes, (ii) neutron stars, (iii) white dwarfs, and (iv) main-sequence stars as microlenses. The Gaia efficiency for detecting the binary signatures in binary astrometric microlensing events is ∼10%–20%. By calculating the optical depth duemore » to the mentioned stellar populations, the numbers of the binary astrometric microlensing events being observed with Gaia with detectable binary signatures, for the binary fraction of about 0.1, are estimated to be 6, 11, 77, and 1316, respectively. Consequently, Gaia can potentially specify the binary fractions of these massive stellar populations. However, the binary fraction of black holes measured with this method has a large uncertainty owing to a low number of the estimated events. Knowing the binary fractions in massive stellar populations helps with studying the gravitational waves. Moreover, we investigate the number of massive microlenses for which Gaia specifies masses through astrometric microlensing of single lenses toward the Galactic bulge. The resulting efficiencies of measuring the mass of mentioned populations are 9.8%, 2.9%, 1.2%, and 0.8%, respectively. The numbers of their astrometric microlensing events being observed in the Gaia era in which the lens mass can be inferred with the relative error less than 0.5 toward the Galactic bulge are estimated as 45, 34, 76, and 786, respectively. Hence, Gaia potentially gives us some information about the mass distribution of these massive stellar populations.« less
Binary Microlensing Events from the MACHO Project

NASA Astrophysics Data System (ADS)

Alcock, C.; Allsman, R. A.; Alves, D.; Axelrod, T. S.; Baines, D.; Becker, A. C.; Bennett, D. P.; Bourke, A.; Brakel, A.; Cook, K. H.; Crook, B.; Crouch, A.; Dan, J.; Drake, A. J.; Fragile, P. C.; Freeman, K. C.; Gal-Yam, A.; Geha, M.; Gray, J.; Griest, K.; Gurtierrez, A.; Heller, A.; Howard, J.; Johnson, B. R.; Kaspi, S.; Keane, M.; Kovo, O.; Leach, C.; Leach, T.; Leibowitz, E. M.; Lehner, M. J.; Lipkin, Y.; Maoz, D.; Marshall, S. L.; McDowell, D.; McKeown, S.; Mendelson, H.; Messenger, B.; Minniti, D.; Nelson, C.; Peterson, B. A.; Popowski, P.; Pozza, E.; Purcell, P.; Pratt, M. R.; Quinn, J.; Quinn, P. J.; Rhie, S. H.; Rodgers, A. W.; Salmon, A.; Shemmer, O.; Stetson, P.; Stubbs, C. W.; Sutherland, W.; Thomson, S.; Tomaney, A.; Vandehei, T.; Walker, A.; Ward, K.; Wyper, G.

2000-09-01

We present the light curves of 21 gravitational microlensing events from the first six years of the MACHO Project gravitational microlensing survey that are likely examples of lensing by binary systems. These events were manually selected from a total sample of ~350 candidate microlensing events that were either detected by the MACHO Alert System or discovered through retrospective analyses of the MACHO database. At least 14 of these 21 events exhibit strong (caustic) features, and four of the events are well fit with lensing by large mass ratio (brown dwarf or planetary) systems, although these fits are not necessarily unique. The total binary event rate is roughly consistent with predictions based upon our knowledge of the properties of binary stars, but a precise comparison cannot be made without a determination of our binary lens event detection efficiency. Toward the Galactic bulge, we find a ratio of caustic crossing to noncaustic crossing binary lensing events of 12:4, excluding one event for which we present two fits. This suggests significant incompleteness in our ability to detect and characterize noncaustic crossing binary lensing. The distribution of mass ratios, N(q), for these binary lenses appears relatively flat. We are also able to reliably measure source-face crossing times in four of the bulge caustic crossing events, and recover from them a distribution of lens proper motions, masses, and distances consistent with a population of Galactic bulge lenses at a distance of 7+/-1 kpc. This analysis yields two systems with companions of ~0.05 Msolar.
Candidate Binary Microlensing Events from the MACHO Project

NASA Astrophysics Data System (ADS)

Becker, A. C.; Alcock, C.; Allsman, R. A.; Alves, D. R.; Axelrod, T. S.; Bennett, D. P.; Cook, K. H.; Drake, A. J.; Freeman, K. C.; Griest, K.; King, L. J.; Lehner, M. J.; Marshall, S. L.; Minniti, D.; Peterson, B. A.; Popowski, P.; Pratt, M. R.; Quinn, P. J.; Rodgers, A. W.; Stubbs, C. W.; Sutherland, W.; Tomaney, A.; Vandehei, T.; Welch, D. L.; Baines, D.; Brakel, A.; Crook, B.; Howard, J.; Leach, T.; McDowell, D.; McKeown, S.; Mitchell, J.; Moreland, J.; Pozza, E.; Purcell, P.; Ring, S.; Salmon, A.; Ward, K.; Wyper, G.; Heller, A.; Kaspi, S.; Kovo, O.; Maoz, D.; Retter, A.; Rhie, S. H.; Stetson, P.; Walker, A.; MACHO Collaboration

1998-12-01

We present the lightcurves of 22 gravitational microlensing events from the first six years of the MACHO Project gravitational microlensing survey which are likely examples of lensing by binary systems. These events were selected from a total sample of ~ 300 events which were either detected by the MACHO Alert System or discovered through retrospective analyses of the MACHO database. Many of these events appear to have undergone a caustic or cusp crossing, and 2 of the events are well fit with lensing by binary systems with large mass ratios, indicating secondary companions of approximately planetary mass. The event rate is roughly consistent with predictions based upon our knowledge of the properties of binary stars. The utility of binary lensing in helping to solve the Galactic dark matter problem is demonstrated with analyses of 3 binary microlensing events seen towards the Magellanic Clouds. Source star resolution during caustic crossings in 2 of these events allows us to estimate the location of the lensing systems, assuming each source is a single star and not a short period binary. * MACHO LMC-9 appears to be a binary lensing event with a caustic crossing partially resolved in 2 observations. The resulting lens proper motion appears too small for a single source and LMC disk lens. However, it is considerably less likely to be a single source star and Galactic halo lens. We estimate the a priori probability of a short period binary source with a detectable binary character to be ~ 10 %. If the source is also a binary, then we currently have no constraints on the lens location. * The most recent of these events, MACHO 98-SMC-1, was detected in real-time. Follow-up observations by the MACHO/GMAN, PLANET, MPS, EROS and OGLE microlensing collaborations lead to the robust conclusion that the lens likely resides in the SMC.
Ground-based Parallax Confirmed by Spitzer: Binary Microlensing Event MOA-2015-BLG-020

NASA Astrophysics Data System (ADS)

Wang, Tianshu; Zhu, Wei; Mao, Shude; Bond, I. A.; Gould, A.; Udalski, A.; Sumi, T.; Bozza, V.; Ranc, C.; Cassan, A.; Yee, J. C.; Han, C.; Abe, F.; Asakura, Y.; Barry, R.; Bennett, D. P.; Bhattacharya, A.; Donachie, M.; Evans, P.; Fukui, A.; Hirao, Y.; Itow, Y.; Kawasaki, K.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyazaki, S.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Rattenbury, N.; Saito, To.; Sharan, A.; Shibai, H.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yamada, T.; Yonehara, A.; MOA Collaboration; KozŁowski, S.; Mróz, P.; Pawlak, M.; Pietrukowicz, P.; Poleski, R.; Skowron, J.; Soszyński, I.; Szymański, M. K.; Ulaczyk, K.; OGLE Collaboration; Beichman, C.; Bryden, G.; Calchi Novati, S.; Carey, S.; Fausnaugh, M.; Gaudi, B. S.; Henderson, C. B.; Shvartzvald, Y.; Wibking, B.; Spitzer Team; Albrow, M. D.; Chung, S.-J.; Hwang, K.-H.; Jung, Y. K.; Ryu, Y.-H.; Shin, I.-G.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, Y.; Park, B.-G.; Pogge, R. W.; KMTNet Collaboration; Street, R. A.; Tsapras, Y.; Hundertmark, M.; Bachelet, E.; Dominik, M.; Horne, K.; Figuera Jaimes, R.; Wambsganss, J.; Bramich, D. M.; Schmidt, R.; Snodgrass, C.; Steele, I. A.; Menzies, J.; RoboNet Collaboration

2017-08-01

We present the analysis of the binary gravitational microlensing event MOA-2015-BLG-020. The event has a fairly long timescale (˜63 days) and thus the light curve deviates significantly from the lensing model that is based on the rectilinear lens-source relative motion. This enables us to measure the microlensing parallax through the annual parallax effect. The microlensing parallax parameters constrained by the ground-based data are confirmed by the Spitzer observations through the satellite parallax method. By additionally measuring the angular Einstein radius from the analysis of the resolved caustic crossing, the physical parameters of the lens are determined. It is found that the binary lens is composed of two dwarf stars with masses {M}1=0.606+/- 0.028 {M}⊙ and {M}2=0.125 +/- 0.006 {M}⊙ in the Galactic disk. Assuming that the source star is at the same distance as the bulge red clump stars, we find the lens is at a distance {D}L=2.44+/- 0.10 {kpc}. We also provide a summary and short discussion of all of the published microlensing events in which the annual parallax effect is confirmed by other independent observations.
The First Planetary Microlensing Event with Two Microlensed Source Stars

NASA Astrophysics Data System (ADS)

Bennett, D. P.; Udalski, A.; Han, C.; Bond, I. A.; Beaulieu, J.-P.; Skowron, J.; Gaudi, B. S.; Koshimoto, N.; Abe, F.; Asakura, Y.; Barry, R. K.; Bhattacharya, A.; Donachie, M.; Evans, P.; Fukui, A.; Hirao, Y.; Itow, Y.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Oyokawa, H.; Ranc, C.; Rattenbury, N. J.; Rosenthal, M. M.; Saito, To.; Sharan, A.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Tristram, P. J.; Yonehara, A.; The MOA Collaboration; Szymański, M. K.; Poleski, R.; Soszyński, I.; Ulaczyk, K.; Wyrzykowski, Ł.; The OGLE Collaboration; DePoy, D.; Gould, A.; Pogge, R. W.; Yee, J. C.; The μFUN Collaboration; Albrow, M. D.; Bachelet, E.; Batista, V.; Bowens-Rubin, R.; Brillant, S.; Caldwell, J. A. R.; Cole, A.; Coutures, C.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Fouqué, P.; Horne, K.; Hundertmark, M.; Kains, N.; Kane, S. R.; Marquette, J.-B.; Menzies, J.; Pollard, K. R.; Ranc, C.; Sahu, K. C.; Wambsganss, J.; Williams, A.; Zub, M.; The PLANET Collaboration

2018-03-01

We present the analysis of the microlensing event MOA-2010-BLG-117, and show that the light curve can only be explained by the gravitational lensing of a binary source star system by a star with a Jupiter-mass ratio planet. It was necessary to modify standard microlensing modeling methods to find the correct light curve solution for this binary source, binary-lens event. We are able to measure a strong microlensing parallax signal, which yields the masses of the host star, M * = 0.58 ± 0.11 M ⊙, and planet, m p = 0.54 ± 0.10M Jup, at a projected star–planet separation of a ⊥ = 2.42 ± 0.26 au, corresponding to a semimajor axis of a=2.9≥nfrac{}{}{0em}{}{+1.6}{-0.6} au. Thus, the system resembles a half-scale model of the Sun–Jupiter system with a half-Jupiter0mass planet orbiting a half-solar-mass star at very roughly half of Jupiter’s orbital distance from the Sun. The source stars are slightly evolved, and by requiring them to lie on the same isochrone, we can constrain the source to lie in the near side of the bulge at a distance of D S = 6.9 ± 0.7 kpc, which implies a distance to the planetary lens system of D L = 3.5 ± 0.4 kpc. The ability to model unusual planetary microlensing events, like this one, will be necessary to extract precise statistical information from the planned large exoplanet microlensing surveys, such as the WFIRST microlensing survey.
Faint-source-star planetary microlensing: the discovery of the cold gas-giant planet OGLE-2014-BLG-0676Lb

NASA Astrophysics Data System (ADS)

Rattenbury, N. J.; Bennett, D. P.; Sumi, T.; Koshimoto, N.; Bond, I. A.; Udalski, A.; Shvartzvald, Y.; Maoz, D.; Jørgensen, U. G.; Dominik, M.; Street, R. A.; Tsapras, Y.; Abe, F.; Asakura, Y.; Barry, R.; Bhattacharya, A.; Donachie, M.; Evans, P.; Freeman, M.; Fukui, A.; Hirao, Y.; Itow, Y.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Oyokawa, H.; Saito, To.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yonehara, A.; Poleski, R.; Skowron, J.; Mróz, P.; Szymański, M. K.; Soszyński, I.; Pietrukowicz, P.; Kozłowski, S.; Ulaczyk, K.; Wyrzykowski, Ł.; Friedmann, M.; Kaspi, S.; Alsubai, K.; Browne, P.; Andersen, J. M.; Bozza, V.; Calchi Novati, S.; Damerdji, Y.; Diehl, C.; Dreizler, S.; Elyiv, A.; Giannini, E.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Liebig, C.; Hundertmark, M.; Juncher, D.; Kains, N.; Kerins, E.; Korhonen, H.; Mancini, L.; Martin, R.; Mathiasen, M.; Rabus, M.; Rahvar, S.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Surdej, J.; Taylor, J.; Tregloan-Reed, J.; Vilela, C.; Wambsganss, J.; Williams, A.; D'Ago, G.; Bachelet, E.; Bramich, D. M.; Figuera Jaimes, R.; Horne, K.; Menzies, J.; Schmidt, R.; Steele, I. A.

2017-04-01

We report the discovery of a planet - OGLE-2014-BLG-0676Lb- via gravitational microlensing. Observations for the lensing event were made by the following groups: Microlensing Observations in Astrophysics; Optical Gravitational Lensing Experiment; Wise Observatory; RoboNET/Las Cumbres Observatory Global Telescope; Microlensing Network for the Detection of Small Terrestrial Exoplanets; and μ-FUN. All analyses of the light-curve data favour a lens system comprising a planetary mass orbiting a host star. The most-favoured binary lens model has a mass ratio between the two lens masses of (4.78 ± 0.13) × 10-3. Subject to some important assumptions, a Bayesian probability density analysis suggests the lens system comprises a 3.09_{-1.12}^{+1.02} MJ planet orbiting a 0.62_{-0.22}^{+0.20} M⊙ host star at a deprojected orbital separation of 4.40_{-1.46}^{+2.16} au. The distance to the lens system is 2.22_{-0.83}^{+0.96} kpc. Planet OGLE-2014-BLG-0676Lb provides additional data to the growing number of cool planets discovered using gravitational microlensing against which planetary formation theories may be tested. Most of the light in the baseline of this event is expected to come from the lens and thus high-resolution imaging observations could confirm our planetary model interpretation.
Faint-Source-Star Planetary Microlensing: The Discovery of the Cold Gas-Giant Planet OGLE-2014-BLG-0676Lb

NASA Technical Reports Server (NTRS)

Rattenbury, N. J.; Bennett, D. P.; Sumi, T.; Koshimoto, N.; Bond, I. A.; Udalski, A.; Shvartzvald, Y.; Maoz, D.; Jorgensen, U. G.; Barry, R.;

2016-01-01

We report the discovery of a planet OGLE-2014-BLG-0676Lb via gravitational microlensing. Observations for the lensing event were made by the following groups: Microlensing Observations in Astrophysics; Optical Gravitational Lensing Experiment; Wise Observatory; RoboNETLas Cumbres Observatory Global Telescope; Microlensing Network for the Detection of Small Terrestrial Exoplanets; and -FUN. All analyses of the light-curve data favoura lens system comprising a planetary mass orbiting a host star. The most-favoured binary lens model has a mass ratio between the two lens masses of (4.78 +/- 0.13) 10(exp -3). Subject to some important assumptions, a Bayesian probability density analysis suggests the lens system comprises a 3.09(+1.02/-1.12) MJ planet orbiting a 0.62(+0.20/-0.22) solar mass host star at a deprojected orbital separation of 4.40(+2.16/-1.46) au. The distance to the lens system is 2.22(+0.96/-0.83) kpc. Planet OGLE-2014-BLG-0676Lb provides additional data to the growing number of cool planets discover redusing gravitational microlensing against which planetary formation theories may be tested. Most of the light in the baseline of this event is expected to come from the lens and thus high-resolution imaging observations could confirm our planetary model interpretation.

OGLE 2003-BLG-235/MOA 2003-BLG-53: A Planetary Microlensing Event

NASA Astrophysics Data System (ADS)

Bond, I. A.; Udalski, A.; Jaroszyński, M.; Rattenbury, N. J.; Paczyński, B.; Soszyński, I.; Wyrzykowski, L.; Szymański, M. K.; Kubiak, M.; Szewczyk, O.; Żebruń, K.; Pietrzyński, G.; Abe, F.; Bennett, D. P.; Eguchi, S.; Furuta, Y.; Hearnshaw, J. B.; Kamiya, K.; Kilmartin, P. M.; Kurata, Y.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Noda, S.; Okajima, K.; Sako, T.; Sekiguchi, T.; Sullivan, D. J.; Sumi, T.; Tristram, P. J.; Yanagisawa, T.; Yock, P. C. M.; OGLE Collaboration

2004-05-01

We present observations of the unusual microlensing event OGLE 2003-BLG-235/MOA 2003-BLG-53. In this event, a short-duration (~7 days) low-amplitude deviation in the light curve due to a single-lens profile was observed in both the MOA (Microlensing Observations in Astrophysics) and OGLE (Optical Gravitational Lensing Experiment) survey observations. We find that the observed features of the light curve can only be reproduced using a binary microlensing model with an extreme (planetary) mass ratio of 0.0039+11-07 for the lensing system. If the lens system comprises a main-sequence primary, we infer that the secondary is a planet of about 1.5 Jupiter masses with an orbital radius of ~3 AU.
Exoplanet detection. A terrestrial planet in a ~1-AU orbit around one member of a ~15-AU binary.

PubMed

Gould, A; Udalski, A; Shin, I-G; Porritt, I; Skowron, J; Han, C; Yee, J C; Kozłowski, S; Choi, J-Y; Poleski, R; Wyrzykowski, Ł; Ulaczyk, K; Pietrukowicz, P; Mróz, P; Szymański, M K; Kubiak, M; Soszyński, I; Pietrzyński, G; Gaudi, B S; Christie, G W; Drummond, J; McCormick, J; Natusch, T; Ngan, H; Tan, T-G; Albrow, M; DePoy, D L; Hwang, K-H; Jung, Y K; Lee, C-U; Park, H; Pogge, R W; Abe, F; Bennett, D P; Bond, I A; Botzler, C S; Freeman, M; Fukui, A; Fukunaga, D; Itow, Y; Koshimoto, N; Larsen, P; Ling, C H; Masuda, K; Matsubara, Y; Muraki, Y; Namba, S; Ohnishi, K; Philpott, L; Rattenbury, N J; Saito, To; Sullivan, D J; Sumi, T; Suzuki, D; Tristram, P J; Tsurumi, N; Wada, K; Yamai, N; Yock, P C M; Yonehara, A; Shvartzvald, Y; Maoz, D; Kaspi, S; Friedmann, M

2014-07-04

Using gravitational microlensing, we detected a cold terrestrial planet orbiting one member of a binary star system. The planet has low mass (twice Earth's) and lies projected at ~0.8 astronomical units (AU) from its host star, about the distance between Earth and the Sun. However, the planet's temperature is much lower, <60 Kelvin, because the host star is only 0.10 to 0.15 solar masses and therefore more than 400 times less luminous than the Sun. The host itself orbits a slightly more massive companion with projected separation of 10 to 15 AU. This detection is consistent with such systems being very common. Straightforward modification of current microlensing search strategies could increase sensitivity to planets in binary systems. With more detections, such binary-star planetary systems could constrain models of planet formation and evolution. Copyright © 2014, American Association for the Advancement of Science.
KOI-3278: a self-lensing binary star system.

PubMed

Kruse, Ethan; Agol, Eric

2014-04-18

Over 40% of Sun-like stars are bound in binary or multistar systems. Stellar remnants in edge-on binary systems can gravitationally magnify their companions, as predicted 40 years ago. By using data from the Kepler spacecraft, we report the detection of such a "self-lensing" system, in which a 5-hour pulse of 0.1% amplitude occurs every orbital period. The white dwarf stellar remnant and its Sun-like companion orbit one another every 88.18 days, a long period for a white dwarf-eclipsing binary. By modeling the pulse as gravitational magnification (microlensing) along with Kepler's laws and stellar models, we constrain the mass of the white dwarf to be ~63% of the mass of our Sun. Further study of this system, and any others discovered like it, will help to constrain the physics of white dwarfs and binary star evolution.
Constraints on the Primordial Black Hole Abundance from the First Advanced LIGO Observation Run Using the Stochastic Gravitational-Wave Background

NASA Astrophysics Data System (ADS)

Wang, Sai; Wang, Yi-Fan; Huang, Qing-Guo; Li, Tjonnie G. F.

2018-05-01

Advanced LIGO's discovery of gravitational-wave events is stimulating extensive studies on the origin of binary black holes. Assuming that the gravitational-wave events can be explained by binary primordial black hole mergers, we utilize the upper limits on the stochastic gravitational-wave background given by Advanced LIGO as a new observational window to independently constrain the abundance of primordial black holes in dark matter. We show that Advanced LIGO's first observation run gives the best constraint on the primordial black hole abundance in the mass range 1 M⊙≲MPBH≲100 M⊙, pushing the previous microlensing and dwarf galaxy dynamics constraints tighter by 1 order of magnitude. Moreover, we discuss the possibility to detect the stochastic gravitational-wave background from primordial black holes, in particular from subsolar mass primordial black holes, by Advanced LIGO in the near future.
Constraints on the Primordial Black Hole Abundance from the First Advanced LIGO Observation Run Using the Stochastic Gravitational-Wave Background.

PubMed

Wang, Sai; Wang, Yi-Fan; Huang, Qing-Guo; Li, Tjonnie G F

2018-05-11

Advanced LIGO's discovery of gravitational-wave events is stimulating extensive studies on the origin of binary black holes. Assuming that the gravitational-wave events can be explained by binary primordial black hole mergers, we utilize the upper limits on the stochastic gravitational-wave background given by Advanced LIGO as a new observational window to independently constrain the abundance of primordial black holes in dark matter. We show that Advanced LIGO's first observation run gives the best constraint on the primordial black hole abundance in the mass range 1M_{⊙}≲M_{PBH}≲100M_{⊙}, pushing the previous microlensing and dwarf galaxy dynamics constraints tighter by 1 order of magnitude. Moreover, we discuss the possibility to detect the stochastic gravitational-wave background from primordial black holes, in particular from subsolar mass primordial black holes, by Advanced LIGO in the near future.
The Optical Gravitational Lensing Experiment. Eclipsing Binary Stars in the Large Magellanic Cloud

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M.; Zebrun, K.; Soszynski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.

2003-03-01

We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive.
WFIRST: Searching for Microlens Planets in Very Wide Orbits and the MOA Microlensing Data Release

NASA Astrophysics Data System (ADS)

Hirao, Yuki; Bennett, David; Sumi, Takahiro; MOA Collaboration

2018-01-01

Gravitational microlensing is an unique technique to detect exoplanets down to low mass planets beyond the snow line because it is sensitive to planets orbiting near the Einstein ring radius of a few AU away from its host star, which is complementary to the other methods. Detecting such planets are important for understanding the formation of our solar system because gas giants and ice giants planets are believed to be formed beyond the snow line, where the protoplanetary disk is cold enough for ice to condense, in the core accretion theory. Microlensing Observations in Astrophysics (MOA) group has conducted high cadence survey observations towards the Galactic bulge to detect exoplanets since 2006 at Mt.John University Observatory in NZ using MOA-II 1.8 meter telescope equipped with a very wide field-of-view MOA-cam3 CCD camera. MOA has alerted about 600 microlensing events every year and detected dozens of exoplanets in wide orbits. Future space telescope, WFIRST will conduct survey observations towards the Galactic bulge and is expected to detect thousands of planets in wide orbit via microlensing to complete the census of exoplanets begun by Kepler Space telescope which found planets in close orbits via transit method. To contribute to the WFIRST and make the microlensing community larger, MOA will open its data from 2006 to 2014 to the public. Through the off-line analysis, we have found some short binary events which were not detected in the real time analysis. Short-timescale microlensing events are important because they are candidates of free-floating or wide-separation planets. The poster will present the data release and some results of the analysis of short-timescale binary events.
The influence of microlensing on spectral line shapes generated by a relativistic accretion disc

NASA Astrophysics Data System (ADS)

Popović, L. Č; Mediavilla, E. G.; Muñoz, J. A.

2001-10-01

We study the influence of gravitational microlensing on the spectral line profiles originating from a relativistic accretion disc. Using the Chen & Halpern model for the disc, we show the noticeable changes that microlensing can induce in the line shape when the Einstein radius associated with the microlens is of a size comparable to that of the accretion disc. Of special interest is the relative enhancement between the blue and red peaks of the line when an off-center microlens affects the approaching and receding parts of the accretion disc asymmetrically. In an AGN formed by a super-massive binary in which the accretion disc is located around one of the super-massive companions (the primary), we discuss the possibility of microlensing by the secondary. In this case the ratio between the blue and red peaks of the line profile would depend on the orbital phase. We have also considered the more standard configuration of microlensing by a star-sized object in an intervening galaxy and find that microlensing may also be detected in the broad emission lines of multiply imaged QSOs. The changes observed in the line profile of Arp 102 B are taken as a reference for exploring both scenarios.

OGLE-2014-BLG-0289: Precise Characterization of a Quintuple-peak Gravitational Microlensing Event

NASA Astrophysics Data System (ADS)

Udalski, A.; Han, C.; Bozza, V.; Gould, A.; Bond, I. A.; and; Mróz, P.; Skowron, J.; Wyrzykowski, Ł.; Szymański, M. K.; Soszyński, I.; Ulaczyk, K.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; The OGLE Collaboration; Abe, F.; Barry, R.; Bennett, D. P.; Bhattacharya, A.; Donachie, M.; Evans, P.; Fukui, A.; Hirao, Y.; Itow, Y.; Kawasaki, K.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyazaki, S.; Munakata, H.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Ranc, C.; Rattenbury, N.; Saito, T.; Sharan, A.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Tristram, P. J.; Yamada, T.; Yonehara, A.; The MOA Collaboration; Street, R. A.; Tsapras, Y.; Bachelet, E.; Bramich, D. M.; DÁgo, G.; Dominik, M.; Figuera Jaimes, R.; Horne, K.; Hundertmark, M.; Kains, N.; Menzies, J.; Schmidt, R.; Snodgrass, C.; Steele, I. A.; Wambsganss, J.; Robonet Collaboration; Pogge, R. W.; Jung, Y. K.; Shin, I.-G.; Yee, J. C.; Kim, W.-T.; The μFun Collaboration; Beichman, C.; Carey, S.; Calchi Novati, S.; Zhu, W.; The Spitzer Team

2018-01-01

We present the analysis of the binary-microlensing event OGLE-2014-BLG-0289. The event light curve exhibits five very unusual peaks, four of which were produced by caustic crossings and the other by a cusp approach. It is found that the quintuple-peak features of the light curve provide tight constraints on the source trajectory, enabling us to precisely and accurately measure the microlensing parallax {π }{{E}}. Furthermore, the three resolved caustics allow us to measure the angular Einstein radius {θ }{{E}}. From the combination of {π }{{E}} and {θ }{{E}}, the physical lens parameters are uniquely determined. It is found that the lens is a binary composed of two M dwarfs with masses {M}1=0.52+/- 0.04 {M}ȯ and {M}2=0.42+/- 0.03 {M}ȯ separated in projection by {a}\\perp =6.4+/- 0.5 {au}. The lens is located in the disk with a distance of {D}{{L}}=3.3+/- 0.3 {kpc}. The reason for the absence of a lensing signal in the Spitzer data is that the time of observation corresponds to the flat region of the light curve.
Astrometric Observation of MACHO Gravitational Microlensing

NASA Technical Reports Server (NTRS)

Boden, A. F.; Shao, M.; Van Buren, D.

1997-01-01

This paper discusses the prospects for astrometric observation of MACHO gravitational microlensing events. We derive the expected astrometric observables for a simple microlensing event assuming a dark MACHO, and demonstrate that accurate astrometry can determine the lens mass, distance, and proper motion in a very general fashion.
Optical gravitational lensing experiment: OGLE-1999-BUL-19 - the first multipeak parallax event

NASA Astrophysics Data System (ADS)

Smith, Martin C.; Mao, Shude; Woźniak, P.; Udalski, A.; Szymański, M.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Żebruń, K.

2002-10-01

We describe a highly unusual microlensing event, OGLE-1999-BUL-19. Unlike most standard microlensing events, this event exhibits multiple peaks in its light curve. The Einstein radius crossing time for this event is approximately 1 yr, which is unusually long. We show that the additional peaks in the light curve can be caused by the very small value for the relative transverse velocity of the lens projected on to the observer plane (). Since this value is significantly less than the speed of the orbit of the Earth around the Sun (v⊕~ 30km s-1), the motion of the Earth induces these multiple peaks in the light curve. This value for is the lowest velocity so far published and we believe that this is the first multiple-peak parallax event ever observed. We also found that the event can be somewhat better fitted by a rotating binary-source model, although this is to be expected since every parallax microlensing event can be exactly reproduced by a suitable binary-source model. A face-on rotating binary-lens model was also identified, but this provides a significantly worse fit. We conclude that the most likely cause for this multipeak behaviour is parallax microlensing rather than microlensing by a binary source. However, this event may be exhibiting a slight binary-source signature in addition to these parallax-induced multiple peaks. With spectroscopic observations it is possible to test this `parallax plus binary-source' hypothesis and (in the instance that the hypothesis turns out to be correct) to simultaneously fit both models and obtain a measurement of the lens mass. Furthermore, spectroscopic observations could also supply information regarding the lens properties, possibly providing another avenue for determining the lens mass. We also investigated the nature of the blending for this event, and found that the majority of the I-band blending is contributed by a source roughly aligned with the lensed source. This implies that most of the I-band blending is caused by light from the lens or a binary companion to the source. However, in the V band, there appears to be a second blended source 0.35 arcsec away from the lensed source. Hubble Space Telescope observations will be very useful for understanding the nature of the blends. We also suggest that a radial velocity survey of all parallax events will be very useful for further constraining the lensing kinematics and understanding the origins of these events and the excess of long events toward the bulge.
Probing the gravitational Faraday rotation using quasar X-ray microlensing.

PubMed

Chen, Bin

2015-11-17

The effect of gravitational Faraday rotation was predicted in the 1950s, but there is currently no practical method for measuring this effect. Measuring this effect is important because it will provide new evidence for correctness of general relativity, in particular, in the strong field limit. We predict that the observed degree and angle of the X-ray polarization of a cosmologically distant quasar microlensed by the random star field in a foreground galaxy or cluster lens vary rapidly and concurrently with flux during caustic-crossing events using the first simulation of quasar X-ray microlensing polarization light curves. Therefore, it is possible to detect gravitational Faraday rotation by monitoring the X-ray polarization of gravitationally microlensed quasars. Detecting this effect will also confirm the strong gravity nature of quasar X-ray emission.
REVIEWS OF TOPICAL PROBLEMS: Gravitational microlensing

NASA Astrophysics Data System (ADS)

Zakharov, Aleksandr F.; Sazhin, Mikhail V.

1998-10-01

The foundations of standard microlensing theory are discussed as applied to stars in the Galactic bulge, Magellanic Clouds or other nearby galaxies and gravitational microlenses assumed to lie in-between these stars and the terrestrial observer. In contrast to the review article by Gurevich et al. [48], microlensing by compact objects is mainly considered. Criteria for the identification of microlensing events are discussed as also are microlensing events not satisfying these criteria, such as non-symmetrical light curves and chromatic and polarization effects. The Large Magellanic Cloud (LMC) and Galactic bulge microlensing data of the MACHO group are discussed in detail and also the LMC data of EROS and the Galactic bulge data of OGLE are presented. A detailed comparison of theoretical predictions and observations is given.
Probing the gravitational Faraday rotation using quasar X-ray microlensing

PubMed Central

Chen, Bin

2015-01-01

The effect of gravitational Faraday rotation was predicted in the 1950s, but there is currently no practical method for measuring this effect. Measuring this effect is important because it will provide new evidence for correctness of general relativity, in particular, in the strong field limit. We predict that the observed degree and angle of the X-ray polarization of a cosmologically distant quasar microlensed by the random star field in a foreground galaxy or cluster lens vary rapidly and concurrently with flux during caustic-crossing events using the first simulation of quasar X-ray microlensing polarization light curves. Therefore, it is possible to detect gravitational Faraday rotation by monitoring the X-ray polarization of gravitationally microlensed quasars. Detecting this effect will also confirm the strong gravity nature of quasar X-ray emission. PMID:26574051
OGLE-2016-BLG-1469L: Microlensing Binary Composed of Brown Dwarfs

NASA Astrophysics Data System (ADS)

Han, C.; Udalski, A.; Sumi, T.; Gould, A.; Albrow, M. D.; Chung, S.-J.; Jung, Y. K.; Ryu, Y.-H.; Shin, I.-G.; Yee, J. C.; Zhu, W.; Cha, S.-M.; Kim, S.-L.; Kim, D.-J.; Lee, C.-U.; Lee, Y.; Park, B.-G.; KMTNet Collaboration; Soszyński, I.; Mróz, P.; Pietrukowicz, P.; Szymański, M. K.; Skowron, J.; Poleski, R.; Kozłowski, S.; Ulaczyk, K.; Pawlak, M.; OGLE Collaboration; Abe, F.; Asakura, Y.; Bennett, D. P.; Bond, I. A.; Bhattacharya, A.; Donachie, M.; Freeman, M.; Fukui, A.; Hirao, Y.; Itow, Y.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Oyokawa, H.; Rattenbury, N. J.; Saito, To.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yamada, T.; Yamada, T.; Yonehara, A.; Barry, R.; MOA Collaboration

2017-07-01

We report the discovery of a binary composed of two brown dwarfs, based on the analysis of the microlensing event OGLE-2016-BLG-1469. Thanks to the detection of both finite-source and microlens-parallax effects, we are able to measure both the masses {M}1˜ 0.05 {M}⊙ and {M}2˜ 0.01 {M}⊙ , and the distance {D}{{L}}˜ 4.5 {kpc}, as well as the projected separation {a}\\perp ˜ 0.33 au. This is the third brown-dwarf binary detected using the microlensing method, demonstrating the usefulness of microlensing in detecting field brown-dwarf binaries with separations of less than 1 au.
Application of Compressive Sensing to Gravitational Microlensing Experiments

NASA Technical Reports Server (NTRS)

Korde-Patel, Asmita; Barry, Richard K.; Mohsenin, Tinoosh

2016-01-01

Compressive Sensing is an emerging technology for data compression and simultaneous data acquisition. This is an enabling technique for significant reduction in data bandwidth, and transmission power and hence, can greatly benefit spaceflight instruments. We apply this process to detect exoplanets via gravitational microlensing. We experiment with various impact parameters that describe microlensing curves to determine the effectiveness and uncertainty caused by Compressive Sensing. Finally, we describe implications for spaceflight missions.
Application of Compressive Sensing to Gravitational Microlensing Experiments

NASA Astrophysics Data System (ADS)

Korde-Patel, Asmita; Barry, Richard K.; Mohsenin, Tinoosh

2017-06-01

Compressive Sensing is an emerging technology for data compression and simultaneous data acquisition. This is an enabling technique for significant reduction in data bandwidth, and transmission power and hence, can greatly benefit space-flight instruments. We apply this process to detect exoplanets via gravitational microlensing. We experiment with various impact parameters that describe microlensing curves to determine the effectiveness and uncertainty caused by Compressive Sensing. Finally, we describe implications for space-flight missions.
REANALYSES OF ANOMALOUS GRAVITATIONAL MICROLENSING EVENTS IN THE OGLE-III EARLY WARNING SYSTEM DATABASE WITH COMBINED DATA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeong, J.; Park, H.; Han, C.

2015-05-01

We reanalyze microlensing events in the published list of anomalous events that were observed from the Optical Gravitational Lensing Experiment (OGLE) lensing survey conducted during the 2004–2008 period. In order to check the existence of possible degenerate solutions and extract extra information, we conduct analyses based on combined data from other survey and follow-up observation and consider higher-order effects. Among the analyzed events, we present analyses of eight events for which either new solutions are identified or additional information is obtained. We find that the previous binary-source interpretations of five events are better interpreted by binary-lens models. These events includemore » OGLE-2006-BLG-238, OGLE-2007-BLG-159, OGLE-2007-BLG-491, OGLE-2008-BLG-143, and OGLE-2008-BLG-210. With additional data covering caustic crossings, we detect finite-source effects for six events including OGLE-2006-BLG-215, OGLE-2006-BLG-238, OGLE-2006-BLG-450, OGLE-2008-BLG-143, OGLE-2008-BLG-210, and OGLE-2008-BLG-513. Among them, we are able to measure the Einstein radii of three events for which multi-band data are available. These events are OGLE-2006-BLG-238, OGLE-2008-BLG-210, and OGLE-2008-BLG-513. For OGLE-2008-BLG-143, we detect higher-order effects induced by the changes of the observer’s position caused by the orbital motion of the Earth around the Sun. In addition, we present degenerate solutions resulting from the known close/wide or ecliptic degeneracy. Finally, we note that the masses of the binary companions of the lenses of OGLE-2006-BLG-450 and OGLE-2008-BLG-210 are in the brown-dwarf regime.« less
A Spectroscopic and Photometric Study of Gravitational Microlensing Events

NASA Astrophysics Data System (ADS)

Kane, Stephen R.

2000-08-01

Gravitational microlensing has generated a great deal of scientific interest over recent years. This has been largely due to the realization of its wide-reaching applications, such as the search for dark matter, the detection of planets, and the study of Galactic structure. A significant observational advance has been that most microlensing events can be identified in real-time while the source is still being lensed. More than 400 microlensing events have now been detected towards the Galactic bulge and Magellanic Clouds by the microlensing survey teams EROS, MACHO, OGLE, DUO, and MOA. The real-time detection of these events allows detailed follow-up observations with much denser sampling, both photometrically and spectroscopically. The research undertaken in this project on photometric studies of gravitational microlensing events has been performed as a member of the PLANET (Probing Lensing Anomalies NETwork) collaboration. This is a worldwide collaboration formed in the early part of 1995 to study microlensing anomalies - departures from an achromatic point source, point lens light curve - through rapidly-sampled, multi-band, photometry. PLANET has demonstrated that it can achieve 1% photometry under ideal circumstances, making PLANET observations sensitive to detection of Earth-mass planets which require characterization of 1%--2% deviations from a standard microlensing light curve. The photometric work in this project involved over 5 months using the 1.0 m telescope at Canopus Observatory in Australia, and 3 separate observing runs using the 0.9 m telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. Methods were developed to reduce the vast amount of photometric data using the image analysis software MIDAS and the photometry package DoPHOT. Modelling routines were then written to analyse a selection of the resulting light curves in order to detect any deviation from an achromatic point source - point lens light curve. The photometric results presented in this thesis are from observations of 34 microlensing events over three consecutive bulge seasons. These results are presented along with a discussion of the observations and the data reduction procedures. The colour-magnitude diagrams indicate that the microlensed sources are main sequence and red clump giant stars. Most of the events appear to exhibit standard Paczynski point source - point lens curves whilst a few deviate significantly from the standard model. Various microlensing models that include anomalous structure are fitted to a selection of the observed events resulting in the discovery of a possible binary source event. These fitted events are used to estimate the sensitivity to extra-solar planets and it is found that the sampling rate for these events was insufficient by about a factor of 7.5 for detecting a Jupiter-mass planet. This result assumes that deviations of 5% can be reliably detected. If microlensing is caused predominantly by bulge stars, as has been suggested by Kiraga and Paczynski, the lensed stars should have larger extinction than other observed stars since they would preferentially be located at the far side of the Galactic bulge. Hence, spectroscopy of Galactic microlensing events may be used as a tool for studying the kinematics and extinction effects in the Galactic bulge. The spectroscopic work in this project involved using Kurucz model spectra to create theoretical extinction effects for various spectral classes towards the Galactic centre. These extinction effects are then used to interpret spectroscopic data taken with the 3.6 m ESO telescope. These data consist of a sample of microlensed stars towards the Galactic bulge and are used to derive the extinction offsets of the lensed source with respect to the average population and a measurement of the fraction of bulge-bulge lensing is made. Hence, it is shown statistically that the microlensed sources are generally located on the far side of the Galactic bulge. Measurements of the radial velocities of these sources are used to determine the kinematic properties of the far side of the Galactic bulge.
Limits on the Mass and Abundance of Primordial Black Holes from Quasar Gravitational Microlensing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mediavilla, E.; Jiménez-Vicente, J.; Calderón-Infante, J.

The idea that dark matter can be made of intermediate-mass primordial black holes (PBHs) in the 10 M {sub ⊙} ≲ M ≲ 200 M {sub ⊙} range has recently been reconsidered, particularly in the light of the detection of gravitational waves by the LIGO experiment. The existence of even a small fraction of dark matter in black holes should nevertheless result in noticeable quasar gravitational microlensing. Quasar microlensing is sensitive to any type of compact objects in the lens galaxy, to their abundance, and to their mass. We have analyzed optical and X-ray microlensing data from 24 gravitationally lensedmore » quasars to estimate the abundance of compact objects in a very wide range of masses. We conclude that the fraction of mass in black holes or any type of compact objects is negligible outside of the 0.05 M {sub ⊙} ≲ M ≲ 0.45 M {sub ⊙} mass range and that it amounts to 20% ± 5% of the total matter, in agreement with the expected masses and abundances of the stellar component. Consequently, the existence of a significant population of intermediate-mass PBHs appears to be inconsistent with current microlensing observations. Therefore, primordial massive black holes are a very unlikely source of the gravitational radiation detected by LIGO.« less
Simulations of the Fe K α Energy Spectra from Gravitationally Microlensed Quasars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krawczynski, H.; Chartas, G., E-mail: krawcz@wustl.edu

The analysis of the Chandra X-ray observations of the gravitationally lensed quasar RX J1131−1231 revealed the detection of multiple and energy-variable spectral peaks. The spectral variability is thought to result from the microlensing of the Fe K α emission, selectively amplifying the emission from certain regions of the accretion disk with certain effective frequency shifts of the Fe K α line emission. In this paper, we combine detailed simulations of the emission of Fe K α photons from the accretion disk of a Kerr black hole with calculations of the effect of gravitational microlensing on the observed energy spectra. Themore » simulations show that microlensing can indeed produce multiply peaked energy spectra. We explore the dependence of the spectral characteristics on black hole spin, accretion disk inclination, corona height, and microlensing amplification factor and show that the measurements can be used to constrain these parameters. We find that the range of observed spectral peak energies of QSO RX J1131−1231 can only be reproduced for black hole inclinations exceeding 70° and for lamppost corona heights of less than 30 gravitational radii above the black hole. We conclude by emphasizing the scientific potential of studies of the microlensed Fe K α quasar emission and the need for more detailed modeling that explores how the results change for more realistic accretion disk and corona geometries and microlensing magnification patterns. A full analysis should furthermore model the signal-to-noise ratio of the observations and the resulting detection biases.« less
Unbound or distant planetary mass population detected by gravitational microlensing.

PubMed

2011-05-19

Since 1995, more than 500 exoplanets have been detected using different techniques, of which 12 were detected with gravitational microlensing. Most of these are gravitationally bound to their host stars. There is some evidence of free-floating planetary-mass objects in young star-forming regions, but these objects are limited to massive objects of 3 to 15 Jupiter masses with large uncertainties in photometric mass estimates and their abundance. Here, we report the discovery of a population of unbound or distant Jupiter-mass objects, which are almost twice (1.8(+1.7)(-0.8)) as common as main-sequence stars, based on two years of gravitational microlensing survey observations towards the Galactic Bulge. These planetary-mass objects have no host stars that can be detected within about ten astronomical units by gravitational microlensing. However, a comparison with constraints from direct imaging suggests that most of these planetary-mass objects are not bound to any host star. An abrupt change in the mass function at about one Jupiter mass favours the idea that their formation process is different from that of stars and brown dwarfs. They may have formed in proto-planetary disks and subsequently scattered into unbound or very distant orbits.
OGLE-2017-BLG-0329L: A Microlensing Binary Characterized with Dramatically Enhanced Precision Using Data from Space-based Observations

NASA Astrophysics Data System (ADS)

Han, C.; Calchi Novati, S.; Udalski, A.; Lee, C.-U.; Gould, A.; Bozza, V.; Mróz, P.; Pietrukowicz, P.; Skowron, J.; Szymański, M. K.; Poleski, R.; Soszyński, I.; Kozłowski, S.; Ulaczyk, K.; Pawlak, M.; Rybicki, K.; Iwanek, P.; The OGLE Collaboration; Albrow, M. D.; Chung, S.-J.; Hwang, K.-H.; Jung, Y. K.; Ryu, Y.-H.; Shin, I.-G.; Shvartzvald, Y.; Yee, J. C.; Zang, W.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.; Kim, W.-T.; The KMTNet Collaboration; Beichman, C.; Bryden, G.; Carey, S.; Gaudi, B. S.; Henderson, C. B.; The Spitzer Team; Dominik, M.; Helling, C.; Hundertmark, M.; Jørgensen, U. G.; Longa-Peña, P.; Lowry, S.; Sajadian, S.; Burgdorf, M. J.; Campbell-White, J.; Ciceri, S.; Evans, D. F.; Haikala, L. K.; Hinse, T. C.; Rahvar, S.; Rabus, M.; Snodgrass, C.; The MiNDSTEp Collaboration

2018-06-01

Mass measurements of gravitational microlenses require one to determine the microlens parallax π E, but precise π E measurement, in many cases, is hampered due to the subtlety of the microlens-parallax signal combined with the difficulty of distinguishing the signal from those induced by other higher-order effects. In this work, we present the analysis of the binary-lens event OGLE-2017-BLG-0329, for which π E is measured with a dramatically improved precision using additional data from space-based Spitzer observations. We find that while the parallax model based on the ground-based data cannot be distinguished from a zero-π E model at the 2σ level, the addition of the Spitzer data enables us to identify two classes of solutions, each composed of a pair of solutions according to the well-known ecliptic degeneracy. It is found that the space-based data reduce the measurement uncertainties of the north and east components of the microlens-parallax vector {{\\boldsymbol{π }}}{{E}} by factors ∼18 and ∼4, respectively. With the measured microlens parallax combined with the angular Einstein radius measured from the resolved caustic crossings, we find that the lens is composed of a binary with component masses of either (M 1, M 2) ∼ (1.1, 0.8) M ⊙ or ∼(0.4, 0.3) M ⊙ according to the two solution classes. The first solution is significantly favored but the second cannot be securely ruled out based on the microlensing data alone. However, the degeneracy can be resolved from adaptive optics observations taken ∼10 years after the event.
Binary Sources and Binary Lenses in Microlensing Surveys of MACHOs

NASA Astrophysics Data System (ADS)

Petrovic, N.; Di Stefano, R.; Perna, R.

2003-12-01

Microlensing is an intriguing phenomenon which may yield information about the nature of dark matter. Early observational searches identified hundreds of microlensing light curves. The data set consisted mainly of point-lens light curves and binary-lens events in which the light curves exhibit caustic crossings. Very few mildly perturbed light curves were observed, although this latter type should constitute the majority of binary lens light curves. Di Stefano (2001) has suggested that the failure to take binary effects into account may have influenced the estimates of optical depth derived from microlensing surveys. The work we report on here is the first step in a systematic analysis of binary lenses and binary sources and their impact on the results of statistical microlensing surveys. In order to asses the problem, we ran Monte-Carlo simulations of various microlensing events involving binary stars (both as the source and as the lens). For each event with peak magnification > 1.34, we sampled the characteristic light curve and recorded the chi squared value when fitting the curve with a point lens model; we used this to asses the perturbation rate. We also recorded the parameters of each system, the maximum magnification, the times at which each light curve started and ended and the number of caustic crossings. We found that both the binarity of sources and the binarity of lenses increased the lensing rate. While the binarity of sources had a negligible effect on the perturbation rates of the light curves, the binarity of lenses had a notable effect. The combination of binary sources and binary lenses produces an observable rate of interesting events exhibiting multiple "repeats" in which the magnification rises above and dips below 1.34 several times. Finally, the binarity of lenses impacted both the durations of the events and the maximum magnifications. This work was supported in part by the SAO intern program (NSF grant AST-9731923) and NASA contracts NAS8-39073 and NAS8-38248 (CXC).
An analytic treatment of gravitational microlensing for sources of finite size at large optical depths

NASA Technical Reports Server (NTRS)

Deguchi, Shuji; Watson, William D.

1988-01-01

Statistical methods are developed for gravitational lensing in order to obtain analytic expressions for the average surface brightness that include the effects of microlensing by stellar (or other compact) masses within the lensing galaxy. The primary advance here is in utilizing a Markoff technique to obtain expressions that are valid for sources of finite size when the surface density of mass in the lensing galaxy is large. The finite size of the source is probably the key consideration for the occurrence of microlensing by individual stars. For the intensity from a particular location, the parameter which governs the importance of microlensing is determined. Statistical methods are also formulated to assess the time variation of the surface brightness due to the random motion of the masses that cause the microlensing.
Microlensing Signature of Binary Black Holes

NASA Technical Reports Server (NTRS)

Schnittman, Jeremy; Sahu, Kailash; Littenberg, Tyson

2012-01-01

We calculate the light curves of galactic bulge stars magnified via microlensing by stellar-mass binary black holes along the line-of-sight. We show the sensitivity to measuring various lens parameters for a range of survey cadences and photometric precision. Using public data from the OGLE collaboration, we identify two candidates for massive binary systems, and discuss implications for theories of star formation and binary evolution.
Detecting and Discriminating Gravitational Microlensing in the SuperMACHO Survey

NASA Astrophysics Data System (ADS)

Garg, Arti

2010-02-01

The SuperMACHO Project is a 5 year survey to determine the nature of the lens population responsible for the excess gravitational microlensing rate toward the Large Magellanic Cloud observed by the MACHO project. The MACHO results indicate a large population of compact lenses toward the clouds, and the observed lensing rate is consistent with a Milky Way halo comprised of up to ˜20% Massive Compact Halo Objects (MACHO's), dark matter that is most likely baryonic. This work describes the method by which gravitational microlensing is detected in the SuperMACHO survey. Based on the MACHO findings and the SuperMACHO observing strategy and selection criteria, we expect <10-6 of the sources monitored to be lensed at any time. Our detection criteria are designed to minimize false positives while preserving a statistically significant detection rate. We provide an overview of the detection criteria. We also discuss the selection criteria used to discriminate between microlensing and other astrophysical transients. )
Microlensing makes lensed quasar time delays significantly time variable

NASA Astrophysics Data System (ADS)

Tie, S. S.; Kochanek, C. S.

2018-01-01

The time delays of gravitationally lensed quasars are generally believed to be unique numbers whose measurement is limited only by the quality of the light curves and the models for the contaminating contribution of gravitational microlensing to the light curves. This belief is incorrect - gravitational microlensing also produces changes in the actual time delays on the ∼day(s) light-crossing time-scale of the emission region. This is due to a combination of the inclination of the disc relative to the line of sight and the differential magnification of the temperature fluctuations producing the variability. We demonstrate this both mathematically and with direct calculations using microlensing magnification patterns. Measuring these delay fluctuations can provide a physical scale for microlensing observations, removing the need for priors on either the microlens masses or the component velocities. That time delays in lensed quasars are themselves time variable likely explains why repeated delay measurements of individual lensed quasars appear to vary by more than their estimated uncertainties. This effect is also a new important systematic problem for attempts to use time delays in lensed quasars for cosmology or to detect substructures (satellites) in lens galaxies.

TWO STARS TWO WAYS: CONFIRMING A MICROLENSING BINARY LENS SOLUTION WITH A SPECTROSCOPIC MEASUREMENT OF THE ORBIT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yee, Jennifer C.; Johnson, John Asher; Eastman, Jason

Light curves of microlensing events involving stellar binaries and planetary systems can provide information about the orbital elements of the system due to orbital modulations of the caustic structure. Accurately measuring the orbit in either the stellar or planetary case requires detailed modeling of subtle deviations in the light curve. At the same time, the natural, Cartesian parameterization of a microlensing binary is partially degenerate with the microlens parallax. Hence, it is desirable to perform independent tests of the predictions of microlens orbit models using radial velocity (RV) time series of the lens binary system. To this end, we presentmore » 3.5 years of RV monitoring of the binary lens system OGLE-2009-BLG-020 L, for which Skowron et al. constrained all internal parameters of the 200–700 day orbit. Our RV measurements reveal an orbit that is consistent with the predictions of the microlens light curve analysis, thereby providing the first confirmation of orbital elements inferred from microlensing events.« less
Late-time high-resolution images of the black hole candidate microlensing events, MACHO-96-BLG-5 and MACHO-98-BLG-6

NASA Astrophysics Data System (ADS)

Forest Stephens, Haynes; Lu, Jessica

2018-01-01

Stellar-mass black holes (BHs) are predicted to be abundant in the Milky Way (N=10^8 - 10^9) but only a few dozen have been detected observationally, all of which are in binary systems and actively accreting. Isolated BHs have yet to be detected. One method for attempting to detect isolated BHs is via gravitational microlensing; when a BH passes in front of a star and briefly magnifies the star's observed brightness. However, during a microlensing event, there is no certain method for determining whether the lens is a BH or another star. We present follow-up observations of two microlensing events, MACHO-1996-BLG-5 and MACHO-1998-BLG-6, which were observed in 1996 and 1998, respectively, and are both long-duration events with a high probability that the lens is a black hole. The closest projected approach between the source and lens was over 20 years ago. If the lens is an isolated BH, then the source and lens should have moved apart enough to be resolved with high-resolution imaging. Using adaptive optics images from the W. M. Keck Observatory, we observed the two candidates in 2016 July. No new sources were found within 0.3 arcseconds of the lensed source, a reasonable angular distance considering the maximum possible relative proper motion of the lens and source. We will present constraints on the lens mass, distance, and proper motion for both microlensing candidates, and explore the likelihood that the lenses are isolated BHs.
Wide-Field InfraRed Survey Telescope (WFIRST) Mission and Synergies with LISA and LIGO-Virgo

NASA Technical Reports Server (NTRS)

Gehrels, N.; Spergel, D.

2015-01-01

The Wide-Field InfraRed Survey Telescope (WFIRST) is a NASA space mission in study for launch in 2024. It has a 2.4 m telescope, wide-field IR instrument operating in the 0.7 - 2.0 micron range and an exoplanet imaging coronagraph instrument operating in the 400 - 1000 nm range. The observatory will perform galaxy surveys over thousands of square degrees to J=27 AB for dark energy weak lensing and baryon acoustic oscillation measurements and will monitor a few square degrees for dark energy SN Ia studies. It will perform microlensing observations of the galactic bulge for an exoplanet census and direct imaging observations of nearby exoplanets with a pathfinder coronagraph. The mission will have a robust and wellfunded guest observer program for 25% of the observing time. WFIRST will be a powerful tool for time domain astronomy and for coordinated observations with gravitational wave experiments. Gravitational wave events produced by mergers of nearby binary neutron stars (LIGO-Virgo) or extragalactic supermassive black hole binaries (LISA) will produce electromagnetic radiation that WFIRST can observe.
Detections of Planets in Binaries Through the Channel of Chang–Refsdal Gravitational Lensing Events

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Cheongho; Shin, In-Gu; Jung, Youn Kil

Chang–Refsdal (C–R) lensing, which refers to the gravitational lensing of a point mass perturbed by a constant external shear, provides a good approximation in describing lensing behaviors of either a very wide or a very close binary lens. C–R lensing events, which are identified by short-term anomalies near the peak of high-magnification lensing light curves, are routinely detected from lensing surveys, but not much attention is paid to them. In this paper, we point out that C–R lensing events provide an important channel to detect planets in binaries, both in close and wide binary systems. Detecting planets through the C–Rmore » lensing event channel is possible because the planet-induced perturbation occurs in the same region of the C–R lensing-induced anomaly and thus the existence of the planet can be identified by the additional deviation in the central perturbation. By presenting the analysis of the actually observed C–R lensing event OGLE-2015-BLG-1319, we demonstrate that dense and high-precision coverage of a C–R lensing-induced perturbation can provide a strong constraint on the existence of a planet in a wide range of planet parameters. The sample of an increased number of microlensing planets in binary systems will provide important observational constraints in giving shape to the details of planet formation, which have been restricted to the case of single stars to date.« less
Precise Time Delays from Strongly Gravitationally Lensed Type Ia Supernovae with Chromatically Microlensed Images

NASA Astrophysics Data System (ADS)

Goldstein, Daniel A.; Nugent, Peter E.; Kasen, Daniel N.; Collett, Thomas E.

2018-03-01

Time delays between the multiple images of strongly gravitationally lensed Type Ia supernovae (glSNe Ia) have the potential to deliver precise cosmological constraints, but the effects of microlensing on time delay extraction have not been studied in detail. Here we quantify the effect of microlensing on the glSN Ia yield of the Large Synoptic Survey Telescope (LSST) and the effect of microlensing on the precision and accuracy of time delays that can be extracted from LSST glSNe Ia. Microlensing has a negligible effect on the LSST glSN Ia yield, but it can be increased by a factor of ∼2 over previous predictions to 930 systems using a novel photometric identification technique based on spectral template fitting. Crucially, the microlensing of glSNe Ia is achromatic until three rest-frame weeks after the explosion, making the early-time color curves microlensing-insensitive time delay indicators. By fitting simulated flux and color observations of microlensed glSNe Ia with their underlying, unlensed spectral templates, we forecast the distribution of absolute time delay error due to microlensing for LSST, which is unbiased at the sub-percent level and peaked at 1% for color curve observations in the achromatic phase, while for light-curve observations it is comparable to state-of-the-art mass modeling uncertainties (4%). About 70% of LSST glSN Ia images should be discovered during the achromatic phase, indicating that microlensing time delay uncertainties can be minimized if prompt multicolor follow-up observations are obtained. Accounting for microlensing, the 1–2 day time delay on the recently discovered glSN Ia iPTF16geu can be measured to 40% precision, limiting its cosmological utility.
Precise Time Delays from Strongly Gravitationally Lensed Type Ia Supernovae with Chromatically Microlensed Images

DOE PAGES

Goldstein, Daniel A.; Nugent, Peter E.; Kasen, Daniel N.; ...

2018-03-01

Time delays between the multiple images of strongly gravitationally lensed Type Ia supernovae (glSNe Ia) have the potential to deliver precise cosmological constraints, but the effects of microlensing on time delay extraction have not been studied in detail. Here we quantify the effect of microlensing on the glSN Ia yield of the Large Synoptic Survey Telescope (LSST) and the effect of microlensing on the precision and accuracy of time delays that can be extracted from LSST glSNe Ia. Microlensing has a negligible effect on the LSST glSN Ia yield, but it can be increased by a factor of ~2 overmore » previous predictions to 930 systems using a novel photometric identification technique based on spectral template fitting. Crucially, the microlensing of glSNe Ia is achromatic until three rest-frame weeks after the explosion, making the early-time color curves microlensing-insensitive time delay indicators. By fitting simulated flux and color observations of microlensed glSNe Ia with their underlying, unlensed spectral templates, we forecast the distribution of absolute time delay error due to microlensing for LSST, which is unbiased at the sub-percent level and peaked at 1% for color curve observations in the achromatic phase, while for light-curve observations it is comparable to state-of-the-art mass modeling uncertainties (4%). About 70% of LSST glSN Ia images should be discovered during the achromatic phase, indicating that microlensing time delay uncertainties can be minimized if prompt multicolor follow-up observations are obtained. Lastly, accounting for microlensing, the 1-2 day time delay on the recently discovered glSN Ia iPTF16geu can be measured to 40% precision, limiting its cosmological utility.« less
Precise Time Delays from Strongly Gravitationally Lensed Type Ia Supernovae with Chromatically Microlensed Images

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldstein, Daniel A.; Nugent, Peter E.; Kasen, Daniel N.

Time delays between the multiple images of strongly gravitationally lensed Type Ia supernovae (glSNe Ia) have the potential to deliver precise cosmological constraints, but the effects of microlensing on time delay extraction have not been studied in detail. Here we quantify the effect of microlensing on the glSN Ia yield of the Large Synoptic Survey Telescope (LSST) and the effect of microlensing on the precision and accuracy of time delays that can be extracted from LSST glSNe Ia. Microlensing has a negligible effect on the LSST glSN Ia yield, but it can be increased by a factor of ~2 overmore » previous predictions to 930 systems using a novel photometric identification technique based on spectral template fitting. Crucially, the microlensing of glSNe Ia is achromatic until three rest-frame weeks after the explosion, making the early-time color curves microlensing-insensitive time delay indicators. By fitting simulated flux and color observations of microlensed glSNe Ia with their underlying, unlensed spectral templates, we forecast the distribution of absolute time delay error due to microlensing for LSST, which is unbiased at the sub-percent level and peaked at 1% for color curve observations in the achromatic phase, while for light-curve observations it is comparable to state-of-the-art mass modeling uncertainties (4%). About 70% of LSST glSN Ia images should be discovered during the achromatic phase, indicating that microlensing time delay uncertainties can be minimized if prompt multicolor follow-up observations are obtained. Lastly, accounting for microlensing, the 1-2 day time delay on the recently discovered glSN Ia iPTF16geu can be measured to 40% precision, limiting its cosmological utility.« less
Gravitational Lensing in Astronomy

NASA Astrophysics Data System (ADS)

Wambsganss, Joachim

1998-11-01

In addition to multiply-imaged quasars, a number of other aspects of lensing have been discovered: For example, giant luminous arcs, quasar microlensing, Einstein rings, galactic microlensing events, arclets, and weak gravitational lensing. At present, literally hundreds of individual gravitational lens phenomena are known. Although still in its childhood, lensing has established itself as a very useful astrophysical tool with some remarkable successes. It has contributed significant new results in areas as different as the cosmological distance scale, the large scale matter distribution in the universe, mass and mass distribution of galaxy clusters, the physics of quasars, dark matter in galaxy halos, and galaxy structure. Looking at these successes in the recent past we predict an even more luminous future for gravitational lensing.
Accelerating gravitational microlensing simulations using the Xeon Phi coprocessor

NASA Astrophysics Data System (ADS)

Chen, B.; Kantowski, R.; Dai, X.; Baron, E.; Van der Mark, P.

2017-04-01

Recently Graphics Processing Units (GPUs) have been used to speed up very CPU-intensive gravitational microlensing simulations. In this work, we use the Xeon Phi coprocessor to accelerate such simulations and compare its performance on a microlensing code with that of NVIDIA's GPUs. For the selected set of parameters evaluated in our experiment, we find that the speedup by Intel's Knights Corner coprocessor is comparable to that by NVIDIA's Fermi family of GPUs with compute capability 2.0, but less significant than GPUs with higher compute capabilities such as the Kepler. However, the very recently released second generation Xeon Phi, Knights Landing, is about 5.8 times faster than the Knights Corner, and about 2.9 times faster than the Kepler GPU used in our simulations. We conclude that the Xeon Phi is a very promising alternative to GPUs for modern high performance microlensing simulations.
Effect of Binary Source Companions on the Microlensing Optical Depth Determination toward the Galactic Bulge Field

NASA Astrophysics Data System (ADS)

Han, Cheongho

2005-11-01

Currently, gravitational microlensing survey experiments toward the Galactic bulge field use two different methods of minimizing the blending effect for the accurate determination of the optical depth τ. One is measuring τ based on clump giant (CG) source stars, and the other is using ``difference image analysis'' (DIA) photometry to measure the unblended source flux variation. Despite the expectation that the two estimates should be the same assuming that blending is properly considered, the estimates based on CG stars systematically fall below the DIA results based on all events with source stars down to the detection limit. Prompted by the gap, we investigate the previously unconsidered effect of companion-associated events on τ determination. Although the image of a companion is blended with that of its primary star and thus not resolved, the event associated with the companion can be detected if the companion flux is highly magnified. Therefore, companions work effectively as source stars to microlensing, and thus the neglect of them in the source star count could result in a wrong τ estimation. By carrying out simulations based on the assumption that companions follow the same luminosity function as primary stars, we estimate that the contribution of the companion-associated events to the total event rate is ~5fbi% for current surveys and can reach up to ~6fbi% for future surveys monitoring fainter stars, where fbi is the binary frequency. Therefore, we conclude that the companion-associated events comprise a nonnegligible fraction of all events. However, their contribution to the optical depth is not large enough to explain the systematic difference between the optical depth estimates based on the two different methods.
Primordial black hole detection through diffractive microlensing

NASA Astrophysics Data System (ADS)

Naderi, T.; Mehrabi, A.; Rahvar, S.

2018-05-01

Recent observations of gravitational waves motivate investigations for the existence of primordial black holes (PBHs). We propose the observation of gravitational microlensing of distant quasars for the range of infrared to the submillimeter wavelengths by sublunar PBHs as lenses. The advantage of observations in the longer wavelengths, comparable to the Schwarzschild radius of the lens (i.e., Rsch≃λ ) is the detection of the wave optics features of the gravitational microlensing. The observation of diffraction pattern in the microlensing light curve of a quasar can break the degeneracy between the lens parameters and determine directly the lens mass as well as the distance of the lens from the observer. We estimate the wave optics optical-depth, also calculate the rate of ˜0.1 to ˜0.3 event per year per a quasar, assuming that hundred percent of dark matter is made of sublunar PBHs. Also, we propose a long-term survey of quasars with the cadence of almost one hour to few days to resolve the wave optics features of the light curves to discover PBHs and determine the fraction of dark matter made of sublunar PBHs as well as their mass function.
Astrophysical Applications of Gravitational Lensing

NASA Astrophysics Data System (ADS)

Mediavilla, Evencio; Muñoz, Jose A.; Garzón, Francisco; Mahoney, Terence J.

2016-10-01

Contributors; Participants; Preface; Acknowledgements; 1. Lensing basics Sherry H. Suyu; 2. Exoplanet microlensing Andrew Gould; 3. Case studies of microlensing Veronica Motta and Emilio Falco; 4. Microlensing of quasars and AGN Joachim Wambsganss; 5. DM in clusters and large-scale structure Peter Schneider; 6. The future of strong lensing Chris Fassnacht; 7. Methods for strong lens modelling Charles Keeton; 8. Tutorial on inverse ray shooting Jorge Jimenez-Vicente.
Microlensing observations rapid search for exoplanets: MORSE code for GPUs

NASA Astrophysics Data System (ADS)

McDougall, Alistair; Albrow, Michael D.

2016-02-01

The rapid analysis of ongoing gravitational microlensing events has been integral to the successful detection and characterization of cool planets orbiting low-mass stars in the Galaxy. In this paper, we present an implementation of search and fit techniques on graphical processing unit (GPU) hardware. The method allows for the rapid identification of candidate planetary microlensing events and their subsequent follow-up for detailed characterization.
OGLE-2016-BLG-1003: First Resolved Caustic-crossing Binary-source Event Discovered by Second-generation Microlensing Surveys

NASA Astrophysics Data System (ADS)

Jung, Y. K.; Udalski, A.; Bond, I. A.; Yee, J. C.; Gould, A.; Han, C.; Albrow, M. D.; Lee, C.-U.; Kim, S.-L.; Hwang, K.-H.; Chung, S.-J.; Ryu, Y.-H.; Shin, I.-G.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Lee, Y.; Park, B.-G.; Kim, H.-W.; Pogge, R. W.; KMTNet Collaboration; Skowron, J.; Szymański, M. K.; Poleski, R.; Mróz, P.; Kozłowski, S.; Pietrukowicz, P.; Soszyński, I.; Ulaczyk, K.; Pawlak, M.; OGLE Collaboration; Abe, F.; Bennett, D. P.; Barry, R.; Sumi, T.; Asakura, Y.; Bhattacharya, A.; Donachie, M.; Fukui, A.; Hirao, Y.; Itow, Y.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Rattenbury, N. J.; Evans, P.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yamada, T.; Yamada, T.; Yonehara, A.; MOA Collaboration

2017-06-01

We report the analysis of the first resolved caustic-crossing binary-source microlensing event OGLE-2016-BLG-1003. The event is densely covered by round-the-clock observations of three surveys. The light curve is characterized by two nested caustic-crossing features, which is unusual for typical caustic-crossing perturbations. From the modeling of the light curve, we find that the anomaly is produced by a binary source passing over a caustic formed by a binary lens. The result proves the importance of high-cadence and continuous observations, and the capability of second-generation microlensing experiments to identify such complex perturbations that are previously unknown. However, the result also raises the issues of the limitations of current analysis techniques for understanding lens systems beyond two masses and of determining the appropriate multiband observing strategy of survey experiments.
Predicting the 4th caustic crossing in Gaia16aye binary microlensing event

NASA Astrophysics Data System (ADS)

Mroz, P.; Wyrzykowski, L.; Rybicki, K.; Altavilla, G.; Bakis, V.; Bendjoya, P.; Birenbaum, G.; Blagorodnova, N.; Blanco-Cuaresma, S.; Bonanos, A.; Bozza, V.; Britavskiy, N.; Burgaz, U.; Butterley, T.; Capuozzo, P.; Carrasco, J. M.; Chruslinska, M.; Damljanovic, G.; Dennefeld, M.; Dhillon, V. S.; Dominik, M.; Esenoglu, H.; Fossey, S.; Gomboc, A.; Hallokoun, N.; Hamanowicz, A.; Hardy, L. K.; Hudec, R.; Khamitov, I.; Klencki, J.; Kolaczkowski, Z.; Kolb, U.; Leonini, S.; Leto, G.; Lewis, F.; Liakos, A.; Littlefair, S. P.; Maoz, D.; Maund, J. R.; Mikolajczyk, P.; Palaversa, L.; Pawlak, M.; Penny, M.; Piascik, A.; Reig, P.; Rhodes, L.; Russell, D.; Sanchez, R. Z.; Shappee, B.; Shvartzvald, Y.; Sitek, M.; Sniegowska, M.; Sokolovsky, K.; Steele, I.; Street, R.; Tomasella, L.; Trascinelli, L.; Wiersema, K.; Wilson, R. W.; Zharkov, I.; Zola, S.; Zubareva, A.

2016-11-01

Gaia16aye, nicknamed Ayers Rock (19:40:01.13 +30:07:53.4, J2000) is a spectacular binary microlensing event in the Northern Galactic Plane. The event has been observed by Gaia, ASAS-SN survey and a network of follow-up telescopes, coordinated by the Time Domain WP of the EC's OPTICON grant.
The Optical Gravitational Lensing Experiment Ogle-Ii Results

NASA Astrophysics Data System (ADS)

Żebruń, K.; Udalski, A.; Szymański, M.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Woźniak, P.

2002-12-01

We present results of a search for microlensing events in the OGLE-II database of observations of stars from the Galactic Bulge (GB). Our main result is the Catalog of Microlensing events in the GB containing data about 214 cases of microlensing in 1997-1999. We present also the distribution of the normalized number of microlensing events in 24 lines of sight. Our results show that the majority of lenses are located in the Galactic Bar rather than in the Galactic disk. Details and the Catalog are available from the OGLE internet archive.
The different origins of high- and low-ionization broad emission lines revealed by gravitational microlensing in the Einstein cross

NASA Astrophysics Data System (ADS)

Braibant, L.; Hutsemékers, D.; Sluse, D.; Anguita, T.

2016-07-01

We investigate the kinematics and ionization structure of the broad emission line region of the gravitationally lensed quasar QSO2237+0305 (the Einstein cross) using differential microlensing in the high- and low-ionization broad emission lines. We combine visible and near-infrared spectra of the four images of the lensed quasar and detect a large-amplitude microlensing effect distorting the high-ionization CIV and low-ionization Hα line profiles in image A. While microlensing only magnifies the red wing of the Balmer line, it symmetrically magnifies the wings of the CIV emission line. Given that the same microlensing pattern magnifies both the high- and low-ionization broad emission line regions, these dissimilar distortions of the line profiles suggest that the high- and low-ionization regions are governed by different kinematics. Since this quasar is likely viewed at intermediate inclination, we argue that the differential magnification of the blue and red wings of Hα favors a flattened, virialized, low-ionization region whereas the symmetric microlensing effect measured in CIV can be reproduced by an emission line formed in a polar wind, without the need of fine-tuned caustic configurations. Based on observations made with the ESO-VLT, Paranal, Chile; Proposals 076.B-0197 and 076.B-0607 (PI: Courbin).
Stellar, Remnant, Planetary, and Dark-Object Masses from Astrometric Microlensing

NASA Technical Reports Server (NTRS)

Gould, Andrew P.; Bennett, David P.; Boden, Andrew; Depoy, Darren L.; Gaudi, Scott B.; Griest, Kim; Han, Cheongho; Paczynski, Bohdan; Reid, I. Neill

2004-01-01

The primary goal of our project is to make a complete census of the stellar population of the Galaxy. We are broadening the term stellar here to include both ordinary stars and dark stars. Ordinary stars, burning their nuclear fuel and shining, can perhaps best be studied with traditional astronomical techniques, but dark stars, by which we include old brown dwarfs, black holes, old white dwarfs, neutron stars, and perhaps exotic objects such as mirror matter stars or primordial black holes, can only be studied by their gravitational effects. Traditionally, these objects have been probed in binaries, and thus selected in a way that may or may not be representative of their respective field populations. The only way to examine the field population of these stars is through microlensing, the deflection of light from a visible star in the background by an object (dark or not) in the foreground. When lensed, there are two images of the background star. Although these images cannot be resolved when the lens has a stellar mass, the lensing effect can be detected in two ways: photometrically, i.e. by measuring the magnification of the source by the lens, and astrometrically, i.e. by measuring the shift in the centroid of the two images. Photometric microlensing experiments have detected hundreds of microlensing events over the past decade. Despite its successes, photometric microlensing has so far been somewhat frustrating because these events are difficult to interpret. Almost nothing is known about the masses of individual lenses and very little is known about the statistical properties of the lenses treated as a whole, such as their average mass. Although probably over 100 of the lenses are in fact dark objects, we can't determine which they are, let alone investigate finer details such as what their masses are, and where they are in the Galaxy. With SIM, we will break the microlensing degeneracy, and allow detailed interpretation of individual microlensing events. We will thus develop a detailed census of the dark and luminous stellar population of the Galaxy.
Discovery of a Jupiter/Saturn analog with gravitational microlensing.

PubMed

Gaudi, B S; Bennett, D P; Udalski, A; Gould, A; Christie, G W; Maoz, D; Dong, S; McCormick, J; Szymanski, M K; Tristram, P J; Nikolaev, S; Paczynski, B; Kubiak, M; Pietrzynski, G; Soszynski, I; Szewczyk, O; Ulaczyk, K; Wyrzykowski, L; Depoy, D L; Han, C; Kaspi, S; Lee, C-U; Mallia, F; Natusch, T; Pogge, R W; Park, B-G; Abe, F; Bond, I A; Botzler, C S; Fukui, A; Hearnshaw, J B; Itow, Y; Kamiya, K; Korpela, A V; Kilmartin, P M; Lin, W; Masuda, K; Matsubara, Y; Motomura, M; Muraki, Y; Nakamura, S; Okumura, T; Ohnishi, K; Rattenbury, N J; Sako, T; Saito, To; Sato, S; Skuljan, L; Sullivan, D J; Sumi, T; Sweatman, W L; Yock, P C M; Albrow, M D; Allan, A; Beaulieu, J-P; Burgdorf, M J; Cook, K H; Coutures, C; Dominik, M; Dieters, S; Fouqué, P; Greenhill, J; Horne, K; Steele, I; Tsapras, Y; Chaboyer, B; Crocker, A; Frank, S; Macintosh, B

2008-02-15

Searches for extrasolar planets have uncovered an astonishing diversity of planetary systems, yet the frequency of solar system analogs remains unknown. The gravitational microlensing planet search method is potentially sensitive to multiple-planet systems containing analogs of all the solar system planets except Mercury. We report the detection of a multiple-planet system with microlensing. We identify two planets with masses of approximately 0.71 and approximately 0.27 times the mass of Jupiter and orbital separations of approximately 2.3 and approximately 4.6 astronomical units orbiting a primary star of mass approximately 0.50 solar mass at a distance of approximately 1.5 kiloparsecs. This system resembles a scaled version of our solar system in that the mass ratio, separation ratio, and equilibrium temperatures of the planets are similar to those of Jupiter and Saturn. These planets could not have been detected with other techniques; their discovery from only six confirmed microlensing planet detections suggests that solar system analogs may be common.
Constraining the geometry and kinematics of the quasar broad emission line region using gravitational microlensing. I. Models and simulations

NASA Astrophysics Data System (ADS)

Braibant, L.; Hutsemékers, D.; Sluse, D.; Goosmann, R.

2017-11-01

Recent studies have shown that line profile distortions are commonly observed in gravitationally lensed quasar spectra. Often attributed to microlensing differential magnification, line profile distortions can provide information on the geometry and kinematics of the broad emission line region (BLR) in quasars. We investigate the effect of gravitational microlensing on quasar broad emission line profiles and their underlying continuum, combining the emission from simple representative BLR models with generic microlensing magnification maps. Specifically, we considered Keplerian disk, polar, and equatorial wind BLR models of various sizes. The effect of microlensing has been quantified with four observables: μBLR, the total magnification of the broad emission line; μcont, the magnification of the underlying continuum; as well as red/blue, RBI and wings/core, WCI, indices that characterize the line profile distortions. The simulations showed that distortions of line profiles, such as those recently observed in lensed quasars, can indeed be reproduced and attributed to the differential effect of microlensing on spatially separated regions of the BLR. While the magnification of the emission line μBLR sets an upper limit on the BLR size and, similarly, the magnification of the continuum μcont sets an upper limit on the size of the continuum source, the line profile distortions mainly depend on the BLR geometry and kinematics. We thus built (WCI,RBI) diagrams that can serve as diagnostic diagrams to discriminate between the various BLR models on the basis of quantitative measurements. It appears that a strong microlensing effect puts important constraints on the size of the BLR and on its distance to the high-magnification caustic. In that case, BLR models with different geometries and kinematics are more prone to produce distinctive line profile distortions for a limited number of caustic configurations, which facilitates their discrimination. When the microlensing effect is weak, there is a larger overlap between the characteristics of the line profile distortions produced by the different models, and constraints can only be derived on a statistical basis.

Gravitational microlensing of gamma-ray bursts

NASA Technical Reports Server (NTRS)

Mao, Shude

1993-01-01

A Monte Carlo code is developed to calculate gravitational microlensing in three dimensions when the lensing optical depth is low or moderate (not greater than 0.25). The code calculates positions of microimages and time delays between the microimages. The majority of lensed gamma-ray bursts should show a simple double-burst structure, as predicted by a single point mass lens model. A small fraction should show complicated multiple events due to the collective effects of several point masses (black holes). Cosmological models with a significant fraction of mass density in massive compact objects can be tested by searching for microlensing events in the current BATSE data. Our catalog generated by 10,000 Monte Carlo models is accessible through the computer network. The catalog can be used to take realistic selection effects into account.
Revisiting Black Holes as Dark Matter

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-02-01

Could dark matter be made of intermediate-mass black holes formed in the beginning of the universe? A recent study takes a renewed look at this question.Galactic LurkersThe nature of dark matter has long been questioned, but the recent discovery of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) has renewed interest in the possibility that dark matter could consist of primordial black holes in the mass range of 101000 solar masses.The relative amounts of the different constituents of the universe. Dark matter makes up roughly 27%. [ESA/Planck]According to this model, the extreme density of matter present during the universes early expansion led to the formation of a large number of intermediate-mass black holes. These black holes now hide in the halos of galaxies, constituting the mass that weve measured dynamically but remains unseen.LIGOs first gravitational-wave detection revealed the merger of two black holes that were both tens of solar masses in size. If primordial black holes are indeed a major constituent of dark matter, then LIGOs detection is consistent with what we would expect to find: occasional mergers of the intermediate-mass black holes that formed in the early universe and now lurk in galactic halos.Quasar MicrolensingTheres a catch, however. If there truly were a large number of intermediate-mass primordial black holes hiding in galactic halos, they wouldnt go completely unnoticed: we would see signs of their presence in the gravitational microlensing of background quasars. Unseen primordial black holes in a foreground galaxy could cause an image of a background quasar to briefly brighten which would provide us with clear evidence of such black holes despite our not being able to detect them directly.A depiction of quasar microlensing (click for a closer look!). The microlensing object in the foreground galaxy could be a star (as depicted), a primordial black hole, or any other compact object. [NASA/Jason Cowan (Astronomy Technology Center)]A team of scientists led by Evencio Mediavilla (Institute of Astrophysics of the Canaries, University of La Laguna) has now used our observations of quasar microlensing to place constraints on the amount of dark matter that could be made up of intermediate-mass primordial black holes.Poor Outlook for Primordial Black HolesMediavilla and collaborators used simulations to estimate the effects of a distribution of masses on light from distant quasars, and they then compared their results to microlensing magnification measurements from 24 gravitationally lensed quasars. In this way, they were able to determine both the abundance and masses of possible objects causing the quasar microlensing effects we see.The authors find that the observations constrain the mass of the possible microlensing objects to be between 0.05 and 0.45 solar masses not at all the intermediate-mass black holes postulated. Whats more, they find that the lensing objects make up 20% of the total matter, which is barely more than expected for normal stellar matter. This suggests that normal stars are doing the majority of the quasar microlensing, not a large population of intermediate-mass black holes.What does this mean for primordial black holes as dark matter? Black holes in the range of 10200 stellar masses are unlikely to account for much (if any) dark matter, Mediavilla and collaborators conclude which means that LIGOs detection of gravitational waves likely came from two black holes collapsed from stars, not primordial black holes.CitationE. Mediavilla et al 2017 ApJL 836 L18. doi:10.3847/2041-8213/aa5dab
Discovery and Mass Measurements of a Cold, Sub-Neptune Mass Planet and Its Host Star

NASA Technical Reports Server (NTRS)

Barry, Richard K., Jr.

2011-01-01

The gravitational microlensing exoplanet detection method is uniquely sensitive to cold, low-mass planets which orbit beyond the snow-line, where the most massive planets are thought to form. The early statistical results from microlensing indicate that Neptune-Saturn mass planets located beyond the snow-line are substantially more common than their counterparts in closer orbits that have found by the Doppler radial velocity method. We present the discovery of the planet MOA-2009-BLG-266Lb, which demonstrates that the gravitational microlensing method also has the capability to measure the masses of cold, low-mass planets. The mass measurements of the host star and the planet are made possible by the detection of the microlensing parallax signal due to the orbital motion or the Earth as well as observations from the EPOXI spacecraft in a Heliocentric orbit. The microlensing light curve indicates a planetary host star mass of M(sun) = 0.54 + / - 0.05M(sun) located at a distance of DL= 2.94 _ 0.21 kpc, orbited by a planet of mass mp= 9.8 +/-1.1M(Earth) with a semi-major axis of a = 3.1(+1.9-0.4)MAU.
X-raying a galactic gravitational lense

NASA Astrophysics Data System (ADS)

Garmire, Gordon

2016-09-01

It can be very difficult to detect compact objects that are not accreting in binary systems. Therefore we know very little about such objects and likely would not notice them even if they are very nearby. Two most obvious examples are very old isolated neutron stars (those that may be beyond the death line and hence are lacking pulsed radio or gamma-ray emission) and isolated stellar-mass black holes (none have been identified so far). OGLE3-ULENSPAR-05 is one of the few massive objects identified in microlensing searches for dark massive objects by the OGLE collaboration. We propose to detect the source or set stringent limit on its X-ray luminosity.
Astrophysical applications of gravitational microlensing

NASA Astrophysics Data System (ADS)

Mao, Shude

2012-08-01

Since the first discovery of microlensing events nearly two decades ago, gravitational microlensing has accumulated tens of TBytes of data and developed into a powerful astrophysical technique with diverse applications. The review starts with a theoretical overview of the field and then proceeds to discuss the scientific highlights. (1) Microlensing observations toward the Magellanic Clouds rule out the Milky Way halo being dominated by MAssive Compact Halo Objects (MACHOs). This confirms most dark matter is non-baryonic, consistent with other observations. (2) Microlensing has discovered about 20 extrasolar planets (16 published), including the first two Jupiter-Saturn like systems and the only five “cold Neptunes" yet detected. They probe a different part of the parameter space and will likely provide the most stringent test of core accretion theory of planet formation. (3) Microlensing provides a unique way to measure the mass of isolated stars, including brown dwarfs and normal stars. Half a dozen or so stellar mass black hole candidates have also been proposed. (4) High-resolution, target-of-opportunity spectra of highly-magnified dwarf stars provide intriguing “age" determinations which may either hint at enhanced helium enrichment or unusual bulge formation theories. (5) Microlensing also measured limb-darkening profiles for close to ten giant stars, which challenges stellar atmosphere models. (6) Data from surveys also provide strong constraints on the geometry and kinematics of the Milky Way bar (through proper motions); the latter indicates predictions from current models appear to be too anisotropic compared with observations. The future of microlensing is bright given the new capabilities of current surveys and forthcoming new telescope networks from the ground and from space. Some open issues in the field are identified and briefly discussed.
Gravitational microlensing by low-mass objects in the globular cluster M22.

PubMed

Sahu, K C; Casertano, S; Livio, M; Gilliland, R L; Panagia, N; Albrow, M D; Potter, M

2001-06-28

Gravitational microlensing offers a means of determining directly the masses of objects ranging from planets to stars, provided that the distances and motions of the lenses and sources can be determined. A globular cluster observed against the dense stellar field of the Galactic bulge presents ideal conditions for such observations because the probability of lensing is high and the distances and kinematics of the lenses and sources are well constrained. The abundance of low-mass objects in a globular cluster is of particular interest, because it may be representative of the very early stages of star formation in the Universe, and therefore indicative of the amount of dark baryonic matter in such clusters. Here we report a microlensing event associated with the globular cluster M22. We determine the mass of the lens to be 0.13(+0.03)(-0.02) solar masses. We have also detected six events that are unresolved in time. If these are also microlensing events, they imply that a non-negligible fraction of the cluster mass resides in the form of free-floating planetary-mass objects.
Gaia16aye binary microlensing event is rising for the 5th time

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Mroz, P.; Rybicki, K.; Altavilla, G.; Bakis, V.; Bendjoya, P.; Birenbaum, G.; Blagorodnova, N.; Blanco-Cuaresma, S.; Bonanos, A.; Bozza, V.; Britavskiy, N.; Burgaz, U.; Butterley, T.; Capuozzo, P.; Carrasco, J. M.; Chruslinska, M.; Damljanovic, G.; Dapergolas, T.; Dennefeld, M.; Dhillon, V. S.; Dominik, M.; Esenoglu, H.; Fossey, S.; Gomboc, A.; Hallokoun, N.; Hamanowicz, A.; Hardy, L. K.; Hudec, R.; Khamitov, I.; Klencki, J.; Kolaczkowski, Z.; Kolb, U.; Leonini, S.; Leto, G.; Lewis, F.; Liakos, A.; Littlefair, S. P.; Maoz, D.; Maund, J. R.; Mikolajczyk, P.; Palaversa, L.; Pawlak, M.; Penny, M.; Piascik, A.; Reig, P.; Rhodes, L.; Russell, D.; Sanchez, R. Z.; Shappee, B.; Shvartzvald, Y.; Sitek, M.; Sniegowska, M.; Sokolovsky, K.; Steele, I.; Street, R.; Tomasella, L.; Trascinelli, L.; Wiersema, K.; Wilson, R. W.; Zharkov, I.; Zola, S.; Zubareva, A.

2017-05-01

Gaia16aye, nicknamed Ayers Rock (19:40:01.13 +30:07:53.4, J2000) was detected in August 2016 and continue on-going, becoming the longest microlensing event found in the Galactic Disk (ATEL #9376, #9507).
Searching for dark matter

NASA Astrophysics Data System (ADS)

Mateo, Mario

1994-01-01

Three teams of astronomers believe they have independently found evidence for dark matter in our galaxy. A brief history of the search for dark matter is presented. The use of microlensing-event observation for spotting dark matter is described. The equipment required to observe microlensing events and three groups working on dark matter detection are discussed. The three groups are the Massive Compact Halo Objects (MACHO) Project team, the Experience de Recherche d'Objets Sombres (EROS) team, and the Optical Gravitational Lensing Experiment (OGLE) team. The first apparent detections of microlensing events by the three teams are briefly reported.
First Lensed Quasar Systems from the VST-ATLAS Survey: One Quad, Two Doubles, and Two Pairs of Lensless Twins

NASA Astrophysics Data System (ADS)

Schechter, Paul L.; Morgan, Nicholas D.; Chehade, B.; Metcalfe, N.; Shanks, T.; McDonald, Michael

2017-05-01

We have analyzed images from the VST-ATLAS survey to identify candidate gravitationally lensed quasar systems in a sample of WISE sources with W1-W2> 0.7. Results from follow-up spectroscopy with the Baade 6.5 m telescope are presented for eight systems. One of them is a quadruply lensed quasar, and two are doubly lensed systems. Two are projected superpositions of two quasars at different redshifts. In one system, two quasars, although at the same redshift, have very different emission line profiles and constitute a physical binary. In two systems, the component spectra are consistent with the lensing hypothesis, after allowing for microlensing. However, as no lensing galaxy is detected in these two systems, we classify them as lensless twins. More extensive observations are needed to establish whether they are in fact lensed quasars or physical binaries. This paper includes data gathered with the 6.5 m Magellan telescopes located at Las Campanas Observatory, Chile.
Astrophysics and astronomy (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 26 January 2011)

NASA Astrophysics Data System (ADS)

2011-10-01

An Astrophysics and Astronomy scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS) was held in the Conference Hall of the P N Lebedev Physical Institute, RAS, on 26 January 2011. The following reports were put on the session's agenda posted on the web site www.gpad.ac.ru of the Physical Sciences Division, RAS: (1) Cherepashchuk A M (Sternberg Astronomical Institute, Moscow State University, Moscow) "Investigation of X-ray sources"; (2) Shustov B M (Institute of Astronomy, Russian Academy of Sciences, Moscow) "Asteroid and comet hazards: physical and other aspects"; (3) Sazhin M V (Sternberg Astronomical Institute, Moscow State University, Moscow) "Search for cosmic strings"; (4) Zakharov A F (Russian Federation State Scientific Center 'A I Alikhanov Institute for Theoretical and Experimental Physics', Moscow) "Exoplanet search using gravitational microlensing". Papers written on the basis of the reports are published below. • Optical investigations of X-ray binary systems, A M Cherepashchuk Physics-Uspekhi, 2011, Volume 54, Number 10, Pages 1061-1067 • Asteroid and comet hazards: the role of physical sciences in solving the problem, B M Shustov Physics-Uspekhi, 2011, Volume 54, Number 10, Pages 1068-1071 • Search for cosmic strings using optical and radio astronomy methods, O S Sazhina, M V Sazhin, M Capaccioli, G Longo Physics-Uspekhi, 2011, Volume 54, Number 10, Pages 1072-1077 • Search for exoplanets using gravitational microlensing, A F Zakharov Physics-Uspekhi, 2011, Volume 54, Number 10, Pages 1077-1084
OGLE-2002-BLG-360: from a gravitational microlensing candidate to an overlooked red transient

NASA Astrophysics Data System (ADS)

Tylenda, R.; Kamiński, T.; Udalski, A.; Soszyński, I.; Poleski, R.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Wyrzykowski, Ł.

2013-07-01

Context. OGLE-2002-BLG-360 was discovered as a microlensing candidate by the OGLE-III project. The subsequent light curve, however, clearly showed that the brightening of the object could not have resulted from the gravitational microlensing phenomenon. Aims: We aim to explain the nature of OGLE-2002-BLG-360 and its eruption observed in 2002-2006. Methods: The observational data primarily come from the archives of the OGLE project, which monitored the object in 2001-2009. The archives of the MACHO and MOA projects also provided us with additional data obtained in 1995-99 and 2000-2005, respectively. These data allowed us to analyse the light curve of the object during its eruption, as well as the potential variability of its progenitor. In the archives of several infrared surveys, namely 2MASS, MSX, Spitzer, AKARI, WISE, and VVV, we found measurements of the object, which allowed us to study the spectral energy distribution (SED) of the object. We constructed a simple model of a star surrounded by a dusty envelope, which was used to interpret the observed SED. Results: Our analysis of the data clearly shows that OGLE-2002-BLG-360 was most probably a red transient, i.e. an object similar in nature to V838 Mon, whose eruption was observed in 2002. The SED in all phases, i.e. progenitor, eruption, and remnant, was dominated by infrared emission, which we interpret as evidence of dust formation in an intense mass outflow. Since 2009 the object has been completely embedded in dust. Conclusions: We suggest that the progenitor of OGLE-2002-BLG-360 was a binary, which had entered the common-envelope phase a long time (at least decades) before the observed eruption, and that the eruption resulted from the final merger of the binary components. We point out similarities between OGLE-2002-BLG-360 and CK Vul, whose eruption was observed in 1670-72, and this strengthens the hypothesis that CK Vul was also a red transient. Based on observations obtained with the 1.3-m Warsaw telescope at the Las Campanas Observatory of the Carnegie Institution for Science.We dedicate this paper to the memory of the late Professor Bohdan Paczyński who, from its discovery, traced the strange behaviour of OGLE-2002-BLG-360 with great interest. The analysis of the light curve of this unusual object maintained his excitement for science, despite serious illness.
OGLE-2015-BLG-0479LA,B: BINARY GRAVITATIONAL MICROLENS CHARACTERIZED BY SIMULTANEOUS GROUND-BASED AND SPACE-BASED OBSERVATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, C.; Udalski, A.; Szymański, M. K.

2016-09-01

We present a combined analysis of the observations of the gravitational microlensing event OGLE-2015-BLG-0479 taken both from the ground and by the Spitzer Space Telescope . The light curves seen from the ground and from space exhibit a time offset of ∼13 days between the caustic spikes, indicating that the relative lens-source positions seen from the two places are displaced by parallax effects. From modeling the light curves, we measure the space-based microlens parallax. Combined with the angular Einstein radius measured by analyzing the caustic crossings, we determine the mass and distance of the lens. We find that the lensmore » is a binary composed of two G-type stars with masses of ∼1.0 M {sub ⊙} and ∼0.9 M {sub ⊙} located at a distance of ∼3 kpc. In addition, we are able to constrain the complete orbital parameters of the lens thanks to the precise measurement of the microlens parallax derived from the joint analysis. In contrast to the binary event OGLE-2014-BLG-1050, which was also observed by Spitzer, we find that the interpretation of OGLE-2015-BLG-0479 does not suffer from the degeneracy between (±, ±) and (±, ∓) solutions, confirming that the four-fold parallax degeneracy in single-lens events collapses into the two-fold degeneracy for the general case of binary-lens events. The location of the blend in the color–magnitude diagram is consistent with the lens properties, suggesting that the blend is the lens itself. The blend is bright enough for spectroscopy and thus this possibility can be checked from future follow-up observations.« less
Strong gravitational lensing: relativity in action

NASA Astrophysics Data System (ADS)

Wambsganss, Joachim

2010-01-01

Deflection of light by gravity was predicted by Einstein's Theory of General Relativity and observationally confirmed in 1919. In the following decades, various aspects of the gravitational lens effect were explored theoretically, among them measuring the Hubble constant from multiple images of a background source, making use of the magnifying effect as a gravitational telescope, or the possibility of a “relativistic eclipse” as a perfect test of GR. Only in 1979, gravitational lensing became an observational science when the first doubly imaged quasar was discovered. Today lensing is a booming part of astrophysics and cosmology. A whole suite of strong lensing phenomena have been investigated: multiple quasars, giant luminous arcs, Einstein rings, quasar microlensing, and galactic microlensing. The most recent lensing application is the detection of extrasolar planets. Lensing has contributed significant new results in areas as different as the cosmological distance scale, mass determination of galaxy clusters, physics of quasars, searches for dark matter in galaxy halos, structure of the Milky Way, stellar atmospheres and exoplanets. A guided tour through some of these applications will illustrate how gravitational lensing has established itself as a very useful universal astrophysical tool.
The Optical Gravitational Lensing Experiment

NASA Technical Reports Server (NTRS)

Udalski, A.; Szymanski, M.; Kaluzny, J.; Kubiak, M.; Mateo, Mario

1992-01-01

The technical features are described of the Optical Gravitational Lensing Experiment, which aims to detect a statistically significant number of microlensing events toward the Galactic bulge. Clusters of galaxies observed during the 1992 season are listed and discussed and the reduction methods are described. Future plans are addressed.
Application of Compressive Sensing to Gravitational Microlensing Data and Implications for Miniaturized Space Observatories

NASA Technical Reports Server (NTRS)

Korde-Patel, Asmita (Inventor); Barry, Richard K.; Mohsenin, Tinoosh

2016-01-01

Compressive Sensing is a technique for simultaneous acquisition and compression of data that is sparse or can be made sparse in some domain. It is currently under intense development and has been profitably employed for industrial and medical applications. We here describe the use of this technique for the processing of astronomical data. We outline the procedure as applied to exoplanet gravitational microlensing and analyze measurement results and uncertainty values. We describe implications for on-spacecraft data processing for space observatories. Our findings suggest that application of these techniques may yield significant, enabling benefits especially for power and volume-limited space applications such as miniaturized or micro-constellation satellites.
Gravitational Lensing and Microlensing in Clusters: Clusters as Dark Matter Telescopes

NASA Astrophysics Data System (ADS)

Safonova, Margarita

2018-04-01

Gravitational lensing is brightening of background objects due to deflection of light by foreground sources. Rich clusters of galaxies are very effective lenses because they are centrally concentrated. Such natural Gravitational Telescopes provide us with strongly magnified galaxies at high redshifts otherwise too faint to be detected or analyzed. With a lensing boost, we can study galaxies shining at the end of the “Dark Ages”. We propose to exploit the opportunity provided by the large field of view and depth, to search for sources magnified by foreground clusters in the vicinity of the cluster critical curves, where enhancements can be of several tens in brightness. Another aspect is microlensing (ML), where we would like to continue our survey of a number of Galactic globular clusters over time-scales of weeks to years to search for ML events from planets to hypothesized central intermediate-mass black holes (IMBH).
Gravitational lens system SDSS J1339+1310: microlensing factory and time delay

NASA Astrophysics Data System (ADS)

Goicoechea, L. J.; Shalyapin, V. N.

2016-12-01

We spectroscopically re-observed the gravitational lens system SDSS J1339+1310 using OSIRIS on the GTC. We also monitored the r-band variability of the two quasar images (A and B) with the LT over 143 epochs in the period 2009-2016. These new data in both the wavelength and time domains have confirmed that the system is an unusual microlensing factory. The C iv emission line is remarkably microlensed, since the microlensing magnification of B relative to that for A, μBA, reaches a value of 1.4 ( 0.4 mag) for its core. Moreover, the B image shows a red wing enhancement of C iv flux (relative to A), and μBA = 2 (0.75 mag) for the C iv broad-line emission. Regarding the nuclear continuum, we find a chromatic behaviour of μBA, which roughly varies from 5 (1.75 mag) at 7000 Å to 6 (1.95 mag) at 4000 Å. We also detect significant microlensing variability in the r band, and this includes a number of microlensing events on timescales of 50-100 d. Fortunately, the presence of an intrinsic 0.7 mag dip in the light curves of A and B, permitted us to measure the time delay between both quasar images. This delay is ΔtAB = 47 d (1σ confidence interval; A is leading), in good agreement with predictions of lens models. Tables 1-3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/596/A77
Fabricating binary optics: An overview of binary optics process technology

NASA Technical Reports Server (NTRS)

Stern, Margaret B.

1993-01-01

A review of binary optics processing technology is presented. Pattern replication techniques have been optimized to generate high-quality efficient microoptics in visible and infrared materials. High resolution optical photolithography and precision alignment is used to fabricate maximally efficient fused silica diffractive microlenses at lambda = 633 nm. The degradation in optical efficiency of four-phase-level fused silica microlenses resulting from an intentional 0.35 micron translational error has been systematically measured as a function of lens speed (F/2 - F/60). Novel processes necessary for high sag refractive IR microoptics arrays, including deep anisotropic Si-etching, planarization of deep topography and multilayer resist techniques, are described. Initial results are presented for monolithic integration of photonic and microoptic systems.
No large population of unbound or wide-orbit Jupiter-mass planets.

PubMed

Mróz, Przemek; Udalski, Andrzej; Skowron, Jan; Poleski, Radosław; Kozłowski, Szymon; Szymański, Michał K; Soszyński, Igor; Wyrzykowski, Łukasz; Pietrukowicz, Paweł; Ulaczyk, Krzysztof; Skowron, Dorota; Pawlak, Michał

2017-08-10

Planet formation theories predict that some planets may be ejected from their parent systems as result of dynamical interactions and other processes. Unbound planets can also be formed through gravitational collapse, in a way similar to that in which stars form. A handful of free-floating planetary-mass objects have been discovered by infrared surveys of young stellar clusters and star-forming regions as well as wide-field surveys, but these studies are incomplete for objects below five Jupiter masses. Gravitational microlensing is the only method capable of exploring the entire population of free-floating planets down to Mars-mass objects, because the microlensing signal does not depend on the brightness of the lensing object. A characteristic timescale of microlensing events depends on the mass of the lens: the less massive the lens, the shorter the microlensing event. A previous analysis of 474 microlensing events found an excess of ten very short events (1-2 days)-more than known stellar populations would suggest-indicating the existence of a large population of unbound or wide-orbit Jupiter-mass planets (reported to be almost twice as common as main-sequence stars). These results, however, do not match predictions of planet-formation theories and surveys of young clusters. Here we analyse a sample of microlensing events six times larger than that of ref. 11 discovered during the years 2010-15. Although our survey has very high sensitivity (detection efficiency) to short-timescale (1-2 days) microlensing events, we found no excess of events with timescales in this range, with a 95 per cent upper limit on the frequency of Jupiter-mass free-floating or wide-orbit planets of 0.25 planets per main-sequence star. We detected a few possible ultrashort-timescale events (with timescales of less than half a day), which may indicate the existence of Earth-mass and super-Earth-mass free-floating planets, as predicted by planet-formation theories.
Microlensing Discovery of an Earth-Mass Planet

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-04-01

What do we know about planet formation around stars that are so light that they cant fuse hydrogen in their cores? The new discovery of an Earth-mass planet orbiting what is likely a brown dwarf may help us better understand this process.Planets Around Brown Dwarfs?Comparison of the sizes of the Sun, a low-mass star, a brown dwarf, Jupiter, and Earth. [NASA/JPL-Caltech/UCB]Planets are thought to form from the material inprotoplanetary disks around their stellar hosts. But the lowest-mass end of the stellar spectrum brown dwarfs, substellar objects so light that they straddle the boundary between planet and star will have correspondingly light disks. Do brown dwarfs disks typically have enough mass to form Earth-mass planets?To answer this question, scientists have searched for planets around brown dwarfs with marginal success. Thus far, only four such planets have been found and these systems may not be typical, since they were discovered via direct imaging. To build a more representative sample, wed like to discover exoplanets around brown dwarfs via a method that doesnt rely on imaging the faint light of the system.A diagram of how planets are detected via gravitational microlensing. The detectable planet is in orbit around the foreground lens star. [NASA]Lensed Light as a GiveawayConveniently, such a method exists and its recently been used to make a major discovery! The planet OGLE-2016-BLG-1195Lb was detected as a result of a gravitational microlensing event that was observed both from the ground and from space.The discovery of a planet via microlensing occurs when the light of a distant source star is magnified by a passing foreground star hosting a planet. The light curve of the source shows a distinctive magnification signature as a result of the gravitational lensing from the foreground star, and the gravitational field of the lensing stars planet can add its own detectable blip to the curve.OGLE-2016-BLG-1195LbThe magnification curve of OGLE-2016-BLG-1195. The peak in the curve in (a) shows the main microlensing by the lens star. An additional blip just after the peak, shown in detail in inset (b), shows the additional lensing by the planet. [Shvartzvald et al. 2017]A team of scientists led by Yossi Shvartzvald (NASA Postdoctoral Fellow at the Jet Propulsion Laboratory) have now presented the discovery of planet OGLE-2016-BLG-1195Lb, which was made using both ground-based (the Korea Microlensing Telescope Network) and space-based (Spitzer) observations of a microlensing event. The combination of these observations allowed the team to determine a number of properties of the system.The teams models indicate that the host is a 0.072 solar-mass ( 74 Jupiter-mass) star, which if it has the same metallicity as the Sun likely lies just below the hydrogen-burning mass limit. A 1.3 Earth-mass planet is orbiting it at a projected separation of 1.11 AU. The system lies in the galactic disk, roughly 13,700 light-years away.Looking to the FutureThis discovery confirms that the protoplanetary disks of ultracool dwarfs do, in fact, contain enough mass to form terrestrial planets. In addition, the find represents a remarkable technical achievement. OGLE-2016-BLG-1195Lb is the lowest-mass planet ever detected using gravitational microlensing, which bodeswell for continued and future microlensing campaigns with high cadences and high detection sensitivity. With luck well soon be able to expand our sample of planets discovered around these unusual hosts, allowing us to build statistics and better understand how and where these planets form.CitationY. Shvartzvald et al 2017 ApJL 840 L3. doi:10.3847/2041-8213/aa6d09

GERLUMPH Data Release 2: 2.5 Billion Simulated Microlensing Light Curves

NASA Astrophysics Data System (ADS)

Vernardos, G.; Fluke, C. J.; Bate, N. F.; Croton, D.; Vohl, D.

2015-04-01

In the upcoming synoptic all-sky survey era of astronomy, thousands of new multiply imaged quasars are expected to be discovered and monitored regularly. Light curves from the images of gravitationally lensed quasars are further affected by superimposed variability due to microlensing. In order to disentangle the microlensing from the intrinsic variability of the light curves, the time delays between the multiple images have to be accurately measured. The resulting microlensing light curves can then be analyzed to reveal information about the background source, such as the size of the quasar accretion disk. In this paper we present the most extensive and coherent collection of simulated microlensing light curves; we have generated \\gt 2.5 billion light curves using the GERLUMPH high resolution microlensing magnification maps. Our simulations can be used to train algorithms to measure lensed quasar time delays, plan future monitoring campaigns, and study light curve properties throughout parameter space. Our data are openly available to the community and are complemented by online eResearch tools, located at http://gerlumph.swin.edu.au.
Strong Gravitational Lensing: Relativity in Action

NASA Astrophysics Data System (ADS)

Wambsganss, Joachim

2009-05-01

Deflection of light by gravity was predicted by Einstein's Theory of General Relativity and observationally confirmed in 1919. In the following decades, various aspects of the gravitational lens effect were explored theoretically, among them measuring the Hubble constant from multiple images of a background source, making use of the magnifying effect as a gravitational telescope, or the possibility of a "relativistic eclipse" as a perfect test of GR. Only in 1979, gravitational lensing became an observational science when the first doubly imaged quasar was discovered. Today lensing is a booming part of astrophysics and cosmology. A whole suite of strong lensing phenomena have been investigated since: multiple quasars, giant luminous arcs, Einstein rings, quasar microlensing, and galactic microlensing. The most recent lensing application is the detection of extrasolar planets. Lensing has contributed significant new results in areas as different as the cosmological distance scale, mass determination of galaxy clusters, physics of quasars, searches for dark matter in galaxy halos, structure of the Milky Way, stellar atmospheres and exoplanets. A guided tour through some of these applications -- with both photometric and astrometric signatures of lensing being discussed -- will illustrate how gravitational lensing has established itself as a very useful universal astrophysical tool.
The gravitational bending of light by stars: a continuing story of curiosity, scepticism, surprise, and fascination

NASA Astrophysics Data System (ADS)

Dominik, Martin

2011-04-01

Driven entirely by human curiosity, the effect of the gravitational bending of light has evolved on unforeseen paths, in an interplay between shifts in prevailing paradigms and advance of technology, into the most unusual way to study planet populations. The confirmation of the bending angle predicted by Einstein with the Solar Eclipse measurements from 1919 marked the breakthrough of the theory of General Relativity, but it was not before the detection of the double image of the quasar 0957+561 that `gravitational lensing' really entered the observational era. The observation of a characteristic transient brightening of a star caused by the gravitational deflection of its light by an intervening foreground star, constituting a `microlensing event', required even further advance in technology before it could first emerge in 1993. While it required more patience in waiting before `Einstein's blip' for the first time revealed the presence of a planet orbiting a star other than the Sun, such detections can now be monitored live, and gravitational microlensing is not only sensitive to masses as low as that of the Moon, but can even reveal planets around stars in galaxies other than the Milky Way.
Statistical improvement in detection level of gravitational microlensing events from their light curves

NASA Astrophysics Data System (ADS)

Ibrahim, Ichsan; Malasan, Hakim L.; Kunjaya, Chatief; Timur Jaelani, Anton; Puannandra Putri, Gerhana; Djamal, Mitra

2018-04-01

In astronomy, the brightness of a source is typically expressed in terms of magnitude. Conventionally, the magnitude is defined by the logarithm of received flux. This relationship is known as the Pogson formula. For received flux with a small signal to noise ratio (S/N), however, the formula gives a large magnitude error. We investigate whether the use of Inverse Hyperbolic Sine function (hereafter referred to as the Asinh magnitude) in the modified formulae could allow for an alternative calculation of magnitudes for small S/N flux, and whether the new approach is better for representing the brightness of that region. We study the possibility of increasing the detection level of gravitational microlensing using 40 selected microlensing light curves from the 2013 and 2014 seasons and by using the Asinh magnitude. Photometric data of the selected events are obtained from the Optical Gravitational Lensing Experiment (OGLE). We found that utilization of the Asinh magnitude makes the events brighter compared to using the logarithmic magnitude, with an average of about 3.42 × 10‑2 magnitude and an average in the difference of error between the logarithmic and the Asinh magnitude of about 2.21 × 10‑2 magnitude. The microlensing events OB140847 and OB140885 are found to have the largest difference values among the selected events. Using a Gaussian fit to find the peak for OB140847 and OB140885, we conclude statistically that the Asinh magnitude gives better mean squared values of the regression and narrower residual histograms than the Pogson magnitude. Based on these results, we also attempt to propose a limit in magnitude value for which use of the Asinh magnitude is optimal with small S/N data.
Combined Analysis of the Binary Lens Caustic-crossing Event MACHO 98-SMC-1

NASA Astrophysics Data System (ADS)

Afonso, C.; Alard, C.; Albert, J. N.; Andersen, J.; Ansari, R.; Aubourg, É.; Bareyre, P.; Bauer, F.; Beaulieu, J. P.; Bouquet, A.; Char, S.; Charlot, X.; Couchot, F.; Coutures, C.; Derue, F.; Ferlet, R.; Glicenstein, J. F.; Goldman, B.; Gould, A.; Graff, D.; Gros, M.; Haissinski, J.; Hamilton, J. C.; Hardin, D.; de Kat, J.; Kim, A.; Lasserre, T.; Lesquoy, É.; Loup, C.; Magneville, C.; Marquette, J. B.; Maurice, É.; Milsztajn, A.; Moniez, M.; Palanque-Delabrouille, N.; Perdereau, O.; Prévot, L.; Regnault, N.; Rich, J.; Spiro, M.; Vidal-Madjar, A.; Vigroux, L.; Zylberajch, S.; Alcock, C.; Allsman, R. A.; Alves, D.; Axelrod, T. S.; Becker, A. C.; Cook, K. H.; Drake, A. J.; Freeman, K. C.; Griest, K.; King, L. J.; Lehner, M. J.; Marshall, S. L.; Minniti, D.; Peterson, B. A.; Pratt, M. R.; Quinn, P. J.; Rodgers, A. W.; Stetson, P. B.; Stubbs, C. W.; Sutherland, W.; Tomaney, A.; Vandehei, T.; Rhie, S. H.; Bennett, D. P.; Fragile, P. C.; Johnson, B. R.; Quinn, J.; Udalski, A.; Kubiak, M.; Szymański, M.; Pietrzyński, G.; Woźniak, P.; Zebruń, K.; Albrow, M. D.; Caldwell, J. A. R.; DePoy, D. L.; Dominik, M.; Gaudi, B. S.; Greenhill, J.; Hill, K.; Kane, S.; Martin, R.; Menzies, J.; Naber, R. M.; Pogge, R. W.; Pollard, K. R.; Sackett, P. D.; Sahu, K. C.; Vermaak, P.; Watson, R.; Williams, A.

2000-03-01

We fit the data for the binary lens microlensing event MACHO 98-SMC-1 from five different microlensing collaborations and find two distinct solutions characterized by binary separation d and mass ratio q: (d,q)=(0.54,0.50) and (d,q)=(3.65,0.36), where d is in units of the Einstein radius. However, the relative proper motion of the lens is very similar in the two solutions, 1.30 km s-1 kpc-1 and 1.48 km s-1 kpc-1, thus confirming that the lens is in the Small Magellanic Cloud. The close binary can be either rotating or approximately static but the wide binary must be rotating at close to its maximum allowed rate to be consistent with all the data. We measure limb-darkening coefficients for five bands ranging from I to V. As expected, these progressively decrease with rising wavelength. This is the first measurement of limb darkening for a metal-poor A star.
OGLE-2016-BLG-0168 Binary Microlensing Event: Prediction and Confirmation of the Microlens Parallax Effect from Space-based Observations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shin, I.-G.; Yee, J. C.; Jung, Y. K.

The microlens parallax is a crucial observable for conclusively identifying the nature of lens systems in microlensing events containing or composed of faint (even dark) astronomical objects such as planets, neutron stars, brown dwarfs, and black holes. With the commencement of a new era of microlensing in collaboration with space-based observations, the microlens parallax can be routinely measured. In addition, space-based observations can provide opportunities to verify the microlens parallax measured from ground-only observations and to find a unique solution to the lensing light-curve analysis. Furthermore, since most space-based observations cannot cover the full light curves of lensing events, itmore » is also necessary to verify the reliability of the information extracted from fragmentary space-based light curves. We conduct a test based on the microlensing event OGLE-2016-BLG-0168, created by a binary lens system consisting of almost equal mass M-dwarf stars, to demonstrate that it is possible to verify the microlens parallax and to resolve degeneracies using the space-based light curve even though the observations are fragmentary. Since space-based observatories will frequently produce fragmentary light curves due to their short observing windows, the methodology of this test will be useful for next-generation microlensing experiments that combine space-based and ground-based collaboration.« less
OGLE-2016-BLG-0168 Binary Microlensing Event: Prediction and Confirmation of the Microlens Parallax Effect from Space-based Observations

NASA Astrophysics Data System (ADS)

Shin, I.-G.; Udalski, A.; Yee, J. C.; Calchi Novati, S.; Han, C.; Skowron, J.; Mróz, P.; Soszyński, I.; Poleski, R.; Szymański, M. K.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Pawlak, M.; OGLE Collaboration; Albrow, M. D.; Gould, A.; Chung, S.-J.; Hwang, K.-H.; Jung, Y. K.; Ryu, Y.-H.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, Y.; Park, B.-G.; Pogge, R. W.; KMTNet Group; Beichman, C.; Bryden, G.; Carey, S.; Gaudi, B. S.; Henderson, C. B.; Shvartzvald, Y.; Spitzer Team

2017-11-01

The microlens parallax is a crucial observable for conclusively identifying the nature of lens systems in microlensing events containing or composed of faint (even dark) astronomical objects such as planets, neutron stars, brown dwarfs, and black holes. With the commencement of a new era of microlensing in collaboration with space-based observations, the microlens parallax can be routinely measured. In addition, space-based observations can provide opportunities to verify the microlens parallax measured from ground-only observations and to find a unique solution to the lensing light-curve analysis. Furthermore, since most space-based observations cannot cover the full light curves of lensing events, it is also necessary to verify the reliability of the information extracted from fragmentary space-based light curves. We conduct a test based on the microlensing event OGLE-2016-BLG-0168, created by a binary lens system consisting of almost equal mass M-dwarf stars, to demonstrate that it is possible to verify the microlens parallax and to resolve degeneracies using the space-based light curve even though the observations are fragmentary. Since space-based observatories will frequently produce fragmentary light curves due to their short observing windows, the methodology of this test will be useful for next-generation microlensing experiments that combine space-based and ground-based collaboration.
a Theoretical Calculation of Microlensing Signatures Caused by Free-Floating Planets Towards the Galactic Bulge

NASA Astrophysics Data System (ADS)

Hamolli, L.; Hafizi, M.; Nucita, A. A.

2013-08-01

Free-floating planets (FFPs) are recently drawing a special interest of the scientific community. Gravitational microlensing is up to now the exclusive method for the investigation of FFPs, including their spatial distribution function and mass function. In this paper, we examine the possibility that the future Euclid space-based observatory may allow to discover a substantial number of microlensing events caused by FFPs. Based on latest results about the free-floating planet (FFP) mass function in the mass range [10-5, 10-2]M⊙, we calculate the optical depth towards the Galactic bulge as well as the expected microlensing rate and find that Euclid may be able to detect hundreds to thousands of these events per month. Making use of a synthetic population, we also investigate the possibility of detecting parallax effect in simulated microlensing events due to FFPs and find a significant efficiency for the parallax detection that turns out to be around 30%.
Extreme magnification of an individual star at redshift 1.5 by a galaxy-cluster lens

NASA Astrophysics Data System (ADS)

Kelly, Patrick L.; Diego, Jose M.; Rodney, Steven; Kaiser, Nick; Broadhurst, Tom; Zitrin, Adi; Treu, Tommaso; Pérez-González, Pablo G.; Morishita, Takahiro; Jauzac, Mathilde; Selsing, Jonatan; Oguri, Masamune; Pueyo, Laurent; Ross, Timothy W.; Filippenko, Alexei V.; Smith, Nathan; Hjorth, Jens; Cenko, S. Bradley; Wang, Xin; Howell, D. Andrew; Richard, Johan; Frye, Brenda L.; Jha, Saurabh W.; Foley, Ryan J.; Norman, Colin; Bradac, Marusa; Zheng, Weikang; Brammer, Gabriel; Benito, Alberto Molino; Cava, Antonio; Christensen, Lise; de Mink, Selma E.; Graur, Or; Grillo, Claudio; Kawamata, Ryota; Kneib, Jean-Paul; Matheson, Thomas; McCully, Curtis; Nonino, Mario; Pérez-Fournon, Ismael; Riess, Adam G.; Rosati, Piero; Schmidt, Kasper Borello; Sharon, Keren; Weiner, Benjamin J.

2018-04-01

Galaxy-cluster gravitational lenses can magnify background galaxies by a total factor of up to 50. Here we report an image of an individual star at redshift z = 1.49 (dubbed MACS J1149 Lensed Star 1) magnified by more than ×2,000. A separate image, detected briefly 0.26″ from Lensed Star 1, is probably a counterimage of the first star demagnified for multiple years by an object of ≳3 solar masses in the cluster. For reasonable assumptions about the lensing system, microlensing fluctuations in the stars' light curves can yield evidence about the mass function of intracluster stars and compact objects, including binary fractions and specific stellar evolution and supernova models. Dark-matter subhaloes or massive compact objects may help to account for the two images' long-term brightness ratio.
Gravitational Lensing in Astronomy.

PubMed

Wambsganss, Joachim

1998-01-01

Deflection of light by gravity was predicted by General Relativity and observationally confirmed in 1919. In the following decades, various aspects of the gravitational lens effect were explored theoretically. Among them were: the possibility of multiple or ring-like images of background sources, the use of lensing as a gravitational telescope on very faint and distant objects, and the possibility of determining Hubble's constant with lensing. It is only relatively recently, (after the discovery of the first doubly imaged quasar in 1979), that gravitational lensing has became an observational science. Today lensing is a booming part of astrophysics. In addition to multiply-imaged quasars, a number of other aspects of lensing have been discovered: For example, giant luminous arcs, quasar microlensing, Einstein rings, galactic microlensing events, arclets, and weak gravitational lensing. At present, literally hundreds of individual gravitational lens phenomena are known. Although still in its childhood, lensing has established itself as a very useful astrophysical tool with some remarkable successes. It has contributed significant new results in areas as different as the cosmological distance scale, the large scale matter distribution in the universe, mass and mass distribution of galaxy clusters, the physics of quasars, dark matter in galaxy halos, and galaxy structure. Looking at these successes in the recent past we predict an even more luminous future for gravitational lensing. Supplementary material is available for this article at 10.12942/lrr-1998-12.
Search for low-mass exoplanets by gravitational microlensing at high magnification.

PubMed

Abe, F; Bennett, D P; Bond, I A; Eguchi, S; Furuta, Y; Hearnshaw, J B; Kamiya, K; Kilmartin, P M; Kurata, Y; Masuda, K; Matsubara, Y; Muraki, Y; Noda, S; Okajima, K; Rakich, A; Rattenbury, N J; Sako, T; Sekiguchi, T; Sullivan, D J; Sumi, T; Tristram, P J; Yanagisawa, T; Yock, P C M; Gal-Yam, A; Lipkin, Y; Maoz, D; Ofek, E O; Udalski, A; Szewczyk, O; Zebrun, K; Soszynski, I; Szymanski, M K; Kubiak, M; Pietrzynski, G; Wyrzykowski, L

2004-08-27

Observations of the gravitational microlensing event MOA 2003-BLG-32/OGLE 2003-BLG-219 are presented, for which the peak magnification was over 500, the highest yet reported. Continuous observations around the peak enabled a sensitive search for planets orbiting the lens star. No planets were detected. Planets 1.3 times heavier than Earth were excluded from more than 50% of the projected annular region from approximately 2.3 to 3.6 astronomical units surrounding the lens star, Uranus-mass planets were excluded from 0.9 to 8.7 astronomical units, and planets 1.3 times heavier than Saturn were excluded from 0.2 to 60 astronomical units. These are the largest regions of sensitivity yet achieved in searches for extrasolar planets orbiting any star.
Search for Low-Mass Exoplanets by Gravitational Microlensing at High Magnification

NASA Astrophysics Data System (ADS)

Abe, F.; Bennett, D. P.; Bond, I. A.; Eguchi, S.; Furuta, Y.; Hearnshaw, J. B.; Kamiya, K.; Kilmartin, P. M.; Kurata, Y.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Noda, S.; Okajima, K.; Rakich, A.; Rattenbury, N. J.; Sako, T.; Sekiguchi, T.; Sullivan, D. J.; Sumi, T.; Tristram, P. J.; Yanagisawa, T.; Yock, P. C. M.; Gal-Yam, A.; Lipkin, Y.; Maoz, D.; Ofek, E. O.; Udalski, A.; Szewczyk, O.; Żebruń, K.; Soszyński, I.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Wyrzykowski, L.

2004-08-01

Observations of the gravitational microlensing event MOA 2003-BLG-32/OGLE 2003-BLG-219 are presented, for which the peak magnification was over 500, the highest yet reported. Continuous observations around the peak enabled a sensitive search for planets orbiting the lens star. No planets were detected. Planets 1.3 times heavier than Earth were excluded from more than 50% of the projected annular region from approximately 2.3 to 3.6 astronomical units surrounding the lens star, Uranus-mass planets were excluded from 0.9 to 8.7 astronomical units, and planets 1.3 times heavier than Saturn were excluded from 0.2 to 60 astronomical units. These are the largest regions of sensitivity yet achieved in searches for extrasolar planets orbiting any star.
New limits on primordial black hole dark matter from an analysis of Kepler source microlensing data.

PubMed

Griest, Kim; Cieplak, Agnieszka M; Lehner, Matthew J

2013-11-01

We present new limits on the allowed masses of a dark matter (DM) halo consisting of primordial black holes (PBH) (or any other massive compact halo object). We analyze two years of data from the Kepler satellite, searching for short-duration bumps caused by gravitational microlensing. After removing background events consisting of variable stars, flare events, and comets or asteroids moving through the Kepler field, we find no microlensing candidates. We measure the efficiency of our selection criteria by adding millions of simulated microlensing lensing events into the Kepler light curves. We find that PBH DM with masses in the range 2 × 10(-9) M[Symbol: see text] to 10(-7)M[Symbol: see text] cannot make up the entirety of the DM in the Milky Way. At the low-mass end, this decreases the allowed mass range by more than an order of magnititude.
Microlensing of Kepler stars as a method of detecting primordial black hole dark matter.

PubMed

Griest, Kim; Lehner, Matthew J; Cieplak, Agnieszka M; Jain, Bhuvnesh

2011-12-02

If the dark matter consists of primordial black holes (PBHs), we show that gravitational lensing of stars being monitored by NASA's Kepler search for extrasolar planets can cause significant numbers of detectable microlensing events. A search through the roughly 150,000 light curves would result in large numbers of detectable events for PBHs in the mass range 5×10(-10) M(⊙) to 10(-4) M(⊙). Nondetection of these events would close almost 2 orders of magnitude of the mass window for PBH dark matter. The microlensing rate is higher than previously noticed due to a combination of the exceptional photometric precision of the Kepler mission and the increase in cross section due to the large angular sizes of the relatively nearby Kepler field stars. We also present a new formalism for calculating optical depth and microlensing rates in the presence of large finite-source effects. © 2011 American Physical Society
OGLE-2015-BLG-0196: GROUND-BASED GRAVITATIONAL MICROLENS PARALLAX CONFIRMED BY SPACE-BASED OBSERVATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, C.; Udalski, A.; Szymański, M. K.

2017-01-01

In this paper, we present an analysis of the binary gravitational microlensing event OGLE-2015-BLG-0196. The event lasted for almost a year, and the light curve exhibited significant deviations from the lensing model based on the rectilinear lens-source relative motion, enabling us to measure the microlens parallax. The ground-based microlens parallax is confirmed by the data obtained from space-based microlens observations using the Spitzer telescope. By additionally measuring the angular Einstein radius from the analysis of the resolved caustic crossing, the physical parameters of the lens are determined up to the twofold degeneracy, u {sub 0} < 0 and u {sub 0} > 0, solutionsmore » caused by the well-known “ecliptic” degeneracy. It is found that the binary lens is composed of two M dwarf stars with similar masses, M {sub 1} = 0.38 ± 0.04 M {sub ⊙} (0.50 ± 0.05 M {sub ⊙}) and M {sub 2} = 0.38 ± 0.04 M {sub ⊙} (0.55 ± 0.06 M {sub ⊙}), and the distance to the lens is D {sub L} = 2.77 ± 0.23 kpc (3.30 ± 0.29 kpc). Here the physical parameters outside and inside the parentheses are for the u {sub 0} < 0 and u {sub 0} > 0 solutions, respectively.« less
MICROLENSING OF QUASAR BROAD EMISSION LINES: CONSTRAINTS ON BROAD LINE REGION SIZE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guerras, E.; Mediavilla, E.; Jimenez-Vicente, J.

2013-02-20

We measure the differential microlensing of the broad emission lines between 18 quasar image pairs in 16 gravitational lenses. We find that the broad emission lines are in general weakly microlensed. The results show, at a modest level of confidence (1.8{sigma}), that high ionization lines such as C IV are more strongly microlensed than low ionization lines such as H{beta}, indicating that the high ionization line emission regions are more compact. If we statistically model the distribution of microlensing magnifications, we obtain estimates for the broad line region size of r{sub s} = 24{sup +22} {sub -15} and r{sub s}more » = 55{sup +150} {sub -35} lt-day (90% confidence) for the high and low ionization lines, respectively. When the samples are divided into higher and lower luminosity quasars, we find that the line emission regions of more luminous quasars are larger, with a slope consistent with the expected scaling from photoionization models. Our estimates also agree well with the results from local reveberation mapping studies.« less
The Frequency of Snowline-Region Planets from Four Years of OGLE-MOA-Wise Second-Generation Microlensing

NASA Technical Reports Server (NTRS)

Shvartzvald, Y.; Maoz, D.; Udalski, A.; Sumi, T.; Friedmann, M.; Kaspi, S.; Poleski, R.; Szymanski, M. K.; Skowron, J.; Kozlowski, S.;

2016-01-01

We present a statistical analysis of the first four seasons from a second-generation microlensing survey for extrasolar planets, consisting of near-continuous time coverage of 8 deg to the 2nd power of the Galactic bulge by the Optical Gravitational Lens Experiment (OGLE), Microlensing Observations in Astrophysics (MOA), and Wise microlensing surveys. During this period, 224 microlensing events were observed by all three groups. Over 12% of the events showed a deviation from single-lens microlensing, and for approx. 1/3 of those the anomaly is likely caused by a planetary companion. For each of the 224 events, we have performed numerical ray-tracing simulations to calculate the detection efficiency of possible companions as a function of companion-to-host mass ratio and separation. Accounting for the detection efficiency, we find that 55 +34 -22%of microlensed stars host a snowline planet. Moreover, we find that Neptune-mass planets are approx.10 times more common than Jupiter-mass planets. The companion-to-host mass-ratio distribution shows a deficit at q approx. 10 (exp -2), separating the distribution into two companion populations, analogous to the stellar-companion and planet populations, seen in radial-velocity surveys around solar-like stars. Our survey, however, which probes mainly lower mass stars, suggests a minimum in the distribution in the super-Jupiter mass range, and a relatively high occurrence of brown-dwarf companions.

Sharpening the tools of gravitational microlensing

NASA Astrophysics Data System (ADS)

Poindexter, Shawn D.

We attempt to identify all microlensing parallax events for which the parallax fit improves Deltachi2 > 100 relative to a standard microlensing model. We outline a procedure to identify three types of discrete degeneracies (including a new one that we dub the "ecliptic degeneracy") and find many new degenerate solutions in 16 previously published and 6 unpublished events. Only four events have one unique solution and the other 18 events have a total of 44 solutions. Our sample includes three previously identified black-hole (BH) candidates. We consider the newly discovered degenerate solutions and determine the relative likelihood that each of these is a BH. We find the lens of event MACHO-99-BLG-22 is a strong BH candidate (78%), event MACHO-96-BLG-5 is a marginal BH candidate (37%), and MACHO-98-BLG-6 is a weak BH candidate (2.2%). The lens of event OGLE-2003-BLG-84 may be a Jupiter-mass free-floating planet candidate based on a weak 3sigma detection of finite-source effects. We find that event MACHO-179-A is a brown dwarf candidate within ˜100 pc of the Sun, mostly due to its very small projected Einstein radius, r˜E = 0.23 +/- 0.05 AU. As expected, these microlensing parallax events are biased toward lenses that are heavier and closer than average. These events were examined for xallarap (or binary-source motion), which can mimic parallax. We find that 23% of these events are strongly affected by xallarap. The mid-IR flux ratios FA/F B = 2.84 +/- 0.06 of the two images of the gravitationally lensed quasar HE 1104--1805 show no wavelength dependence to within 3% across 3.6--8.0 mum, no time dependence over 6 months and agree with the broad emission line flux ratios. This indicates that the mid-IR emission likely comes from scales large enough to be little affected by microlensing and that there is little differential extinction between the images. We measure a revised time-delay between these two images of 152.2+2.8-3.0 (1sigma) days from R and V-band data covering 1997 to 2006. This time-delay indicates that the lens has an approximately flat rotation curve over scales of 1-2 Re. We also observed uncorrelated variations of ˜0.05 mag yr--1 which we attribute to microlensing of the optical emission from the accretion disk. The optical colors have also changed significantly in the sense that image A is now redder than image B, rather than bluer as it was in 1993. Based on the microlensing variability of the two-image gravitational lens HE 1104--1805 observed between 0.4 and 8 mum, we have measured the size and wavelength-dependent structure of the quasar accretion disk. Modeled as a power law in temperature, T ∝ R--beta, we measure a B-band (0.13 mum in the rest frame) half-light radius of R1/2,B = 6.7+6.2-3.2 x 1015 cm (68% CL) and a logarithmic slope of beta = 0.61+0.21-0.17 (68% CL) for our standard model with a logarithmic prior on the disk size. Both the scale and the slope are consistent with simple thin disk models where beta = 3/4 and R1/2,B = 5.9 x 10 15 cm for a Shakura-Sunyaev disk radiating at the Eddington limit with 10% efficiency. The observed fluxes favor a slightly shallower slope, beta = 0.55+0.03-0.02 , and a significantly smaller size for beta = 3/4. Using 11-years of OGLE V-band photometry of Q2237+0305, we measure the transverse velocity of the lens galaxy and the mean mass of its stars. We can do so because, for the first time, we fully include the random motions of the stars in the lens galaxy in the analysis of the light curves. We find the best fit transverse velocity of the lens galaxy is ˜420km s --1 to the Northeast or Southwest -- in the absence of significant streaming velocities we cannot eliminate a 180° reversal symmetry. The mean stellar mass is = 0.37+1.07-0.26 after including a well-defined velocity prior. We also show for the first time that analyzing subsets of a microlensing light curve, in this case the first and second halves of the OGLE V-band light curve, give mutually consistent physical results. Using a microlensing analysis of 11-years of OGLE V-band photometry of the four image gravitational lens Q2237+0305, we measure the inclination i of the accretion disk to be cos i > 0.63 at 68% confidence. Very edge on (cos i < 0.34) solutions are ruled out at 95% confidence. We measure the V-band radius of the accretion disk, defined by the radius where the temperature matches the monitoring band photon emission, to be RV = 6.2+3.8-2.7 x 1015 cm assuming a simple thin disk model and including the uncertainties of its inclination. The projected radiating area of the disk remains too large to be consistent with the observed flux for a T ∝ R--3/4 thin disk temperature profile. There is no strong correlation between the direction of motion (peculiar velocity) of the lens galaxy and the orientation of the disk.
Microlensing and Intrinsic Variability of the Broad Emission Lines of Lensed Quasars

NASA Astrophysics Data System (ADS)

Fian, C.; Guerras, Eduardo; Mediavilla, E.; Jiménez-Vicente, J.; Muñoz, J. A.; Falco, E. E.; Motta, V.; Hanslmeier, A.

2018-05-01

We study the broad emission lines in a sample of 11 gravitationally lensed quasars with at least two epochs of observation to identify intrinsic variability and to disentangle it from microlensing. To improve our statistical significance and emphasize trends, we also include 15 lens systems with single-epoch spectra. Mg II and C III] emission lines are only weakly affected by microlensing, but C IV shows strong microlensing in some cases, even for regions of the line core, presumably associated with small projected velocities. However, excluding the strongly microlensed cases, there is a strikingly good match, on average, between the red wings of the C IV and C III] profiles. Analysis of these results supports the existence of two regions in the broad-line region (BLR), one that is insensitive to microlensing (of size ≳50 lt-day and kinematics not confined to a plane) and another that shows up only when it is magnified by microlensing (of size of a few light-days, comparable to the accretion disk). Both regions can contribute in different proportions to the emission lines of different species and, within each line profile, to different velocity bins, all of which complicates detailed studies of the BLR based on microlensing size estimates. The strength of the microlensing indicates that some spectral features that make up the pseudo-continuum, such as the shelf-like feature at λ1610 or several Fe III blends, may in part arise from an inner region of the accretion disk. In the case of Fe II, microlensing is strong in some blends but not in others. This opens up interesting possibilities to study quasar accretion disk kinematics. Intrinsic variability seems to affect the same features prone to microlensing, with similar frequency and amplitude, but does not induce outstanding profile asymmetries. We measure intrinsic variability (≲20%) of the wings with respect to the cores in the C IV, C III], and Mg II lines consistent with reverberation mapping studies.
Spectroscopic Results of Gravitational Microlenses: Are These Dark Objects or Faint Stars?

NASA Astrophysics Data System (ADS)

Joseph, C. L.; Gallagher, J.; Phillips, M.

1994-12-01

We report on the spectroscopic results obtained in October 1994 with the 4-meter telescope on Cerro Tololo Interamerican Observatory (CTIO). Spectra of 2 recent microlens candidates toward the Galactic bulge reported by the Optical Gravitational Lens Experiment (OGLE) as well as one caught in the early phases of brightening toward the LMC reported by the MAssive Compact Halo Object (MACHO) Project have been obtained. The spectral coverage is from 6500 to 9800 Angstroms at a resolution of 6 Angstroms. The long-term goal of this spectroscopic study is to obtain censored statistical evidence on the luminosity of the microlenses, constraining the nature of these lenses. Several models of composite spectra of a bulge or LMC star plus a cool lensing star of different spectral types are presented to demonstrate the ranges in the product of luminosity times distance that the faint star could be detected in a composite spectrum.

Probing the Broad-Line Region and the Accretion Disk in the Lensed Quasars HE 0435-1223, WFI 2033-4723, and HE 2149-2745 Using Gravitational Microlensing

NASA Astrophysics Data System (ADS)

Motta, V.; Mediavilla, E.; Rojas, K.; Falco, E. E.; Jiménez-Vicente, J.; Muñoz, J. A.

2017-02-01

We use single-epoch spectroscopy of three gravitationally lensed quasars, HE 0435-1223, WFI 2033-4723, and HE 2149-2745, to study their inner structure (broad-line region [BLR] and continuum source). We detect microlensing-induced magnification in the wings of the broad emission lines of two of the systems (HE 0435-1223 and WFI 2033-4723). In the case of WFI 2033-4723, microlensing affects two “bumps” in the spectra that are almost symmetrically arranged on the blue (coincident with an Al III emission line) and red wings of C III]. These match the typical double-peaked profile that follows from disk kinematics. The presence of microlensing in the wings of the emission lines indicates the existence of two different regions in the BLR: a relatively small one with kinematics possibly related to an accretion disk, and another one that is substantially more extended and insensitive to microlensing. There is good agreement between the estimated size of the region affected by microlensing in the emission lines, {r}s={10}-7+15\\sqrt{M/{M}⊙ } lt-day (red wing of C IV in HE 0435-1223) and {r}s={11}-7+28\\sqrt{M/{M}⊙ } lt-day (C III] bumps in WFI 2033-4723), and the sizes inferred from the continuum emission, {r}s={13}-4+5\\sqrt{M/{M}⊙ } lt-day (HE 0435-1223) and {r}s={10}-2+3\\sqrt{M/{M}⊙ } lt-day (WFI 2033-4723). For HE 2149-2745 we measure an accretion disk size {r}s={8}-5+11\\sqrt{M/{M}⊙ } lt-day. The estimates of p, the exponent of the size versus wavelength ({r}s\\propto {λ }p), are 1.2 ± 0.6, 0.8 ± 0.2, and 0.4 ± 0.3 for HE 0435-1223, WFI 2033-4723, and HE 2149-2745, respectively. In conclusion, the continuum microlensing amplitude in the three quasars and chromaticity in WFI 2033-4723 and HE 2149-2745 are below expectations for the thin-disk model. The disks are larger and their temperature gradients are flatter than predicted by this model.
Studying planet populations with Einstein's blip.

PubMed

Dominik, Martin

2010-08-13

Although Einstein originally judged that 'there is no great chance of observing this phenomenon', the 'most curious effect' of the bending of starlight by the gravity of intervening foreground stars--now commonly referred to as 'gravitational microlensing'--has become one of the successfully applied techniques to detect planets orbiting stars other than the Sun, while being quite unlike any other. With more than 400 extra-solar planets known altogether, the discovery of a true sibling of our home planet seems to have become simply a question of time. However, in order to properly understand the origin of Earth, carrying all its various life forms, models of planet formation and orbital evolution need to be brought into agreement with the statistics of the full variety of planets like Earth and unlike Earth. Given the complementarity of the currently applied planet detection techniques, a comprehensive picture will only arise from a combination of their respective findings. Gravitational microlensing favours a range of orbital separations that covers planets whose orbital periods are too long to allow detection by other indirect techniques, but which are still too close to their host star to be detected by means of their emitted or reflected light. Rather than being limited to the Solar neighbourhood, a unique opportunity is provided for inferring a census of planets orbiting stars belonging to two distinct populations within the Milky Way, with a sensitivity not only reaching down to Earth mass, but even below, with ground-based observations. The capabilities of gravitational microlensing extend even to obtaining evidence of a planet orbiting a star in another galaxy.
The first eclipsing binary catalogue from the MOA-II data base

NASA Astrophysics Data System (ADS)

Li, M. C. A.; Rattenbury, N. J.; Bond, I. A.; Sumi, T.; Bennett, D. P.; Koshimoto, N.; Abe, F.; Asakura, Y.; Barry, R.; Bhattacharya, A.; Donachie, M.; Evans, P.; Freeman, M.; Fukui, A.; Hirao, Y.; Itow, Y.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Saito, To.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yonehara, A.

2017-09-01

We present the first catalogue of eclipsing binaries in two MOA (Microlensing Observations in Astrophysics) fields towards the Galactic bulge, in which over 8000 candidates, mostly contact and semidetached binaries of periods <1 d, were identified. In this paper, the light curves of a small number of interesting candidates, including eccentric binaries, binaries with noteworthy phase modulations and eclipsing RS Canum Venaticorum type stars, are shown as examples. In addition, we identified three triple object candidates by detecting the light-travel-time effect in their eclipse time variation curves.
Probing Extragalactic Planets Using Quasar Microlensing

NASA Astrophysics Data System (ADS)

Dai, Xinyu; Guerras, Eduardo

2018-02-01

Previously, planets have been detected only in the Milky Way galaxy. Here, we show that quasar microlensing provides a means to probe extragalactic planets in the lens galaxy, by studying the microlensing properties of emission close to the event horizon of the supermassive black hole of the background quasar, using the current generation telescopes. We show that a population of unbound planets between stars with masses ranging from Moon to Jupiter masses is needed to explain the frequent Fe Kα line energy shifts observed in the gravitationally lensed quasar RXJ 1131–1231 at a lens redshift of z = 0.295 or 3.8 billion lt-yr away. We constrain the planet mass-fraction to be larger than 0.0001 of the halo mass, which is equivalent to 2000 objects ranging from Moon to Jupiter mass per main-sequence star.
Structure of Quasar Continuum Emission Regions and Cosmology from Optical and X-Ray Microlensing in Gravitationally Lensed Quasars

DTIC Science & Technology

2008-05-02

information is estimated to average 1 hour per response, including g the time for reviewing instructions, searching existing data sources, gathering...their central engines cannot be resolved with ordinary telescopes. Gravitational telescopes, however, provide the necessary resolution to study the...structure of the continuum emission regions at optical and X-ray wavelengths and make time delay estimates in the systems in which sufficient data were
Weak deflection gravitational lensing for photons coupled to Weyl tensor in a Schwarzschild black hole

NASA Astrophysics Data System (ADS)

Cao, Wei-Guang; Xie, Yi

2018-03-01

Beyond the Einstein-Maxwell model, electromagnetic field might couple with gravitational field through the Weyl tensor. In order to provide one of the missing puzzles of the whole physical picture, we investigate weak deflection lensing for photons coupled to the Weyl tensor in a Schwarzschild black hole under a unified framework that is valid for its two possible polarizations. We obtain its coordinate-independent expressions for all observables of the geometric optics lensing up to the second order in the terms of ɛ which is the ratio of the angular gravitational radius to angular Einstein radius of the lens. These observables include bending angle, image position, magnification, centroid and time delay. The contributions of such a coupling on some astrophysical scenarios are also studied. We find that, in the cases of weak deflection lensing on a star orbiting the Galactic Center Sgr A*, Galactic microlensing on a star in the bulge and astrometric microlensing by a nearby object, these effects are beyond the current limits of technology. However, measuring the variation of the total flux of two weak deflection lensing images caused by the Sgr A* might be a promising way for testing such a coupling in the future.
Chromatic microlensing in HE0047-1756 and SDSS1155+6346

NASA Astrophysics Data System (ADS)

Rojas, K.; Motta, V.; Mediavilla, E.; Falco, E.; Muñoz, J. A.

2014-10-01

The gravitational lens effect occurs when the light is deflected in the presence of a gravitational field, generating multiple images or arcs. Microlensing happens when a compact object, in the lens galaxy halo, passes across a quasar lensed image. We analyzed two double systems: HE0047-1756 and SDSS1155+6346. We used spectra obtained with Magellan/IMACS (2007) and MMT/Blue-Channel (2008). The flux of emission line cores was separated from the continuum flux under them and integrated using DIPSO software. Comparing the magnitude differences in the emission line cores with the magnitude differences in the continuum under the lines (Motta et. al 2012), we found evidence of chromatic microlensing in HE0047-1756 and SDSS1155+6346. Emission line core fluxes are used to model the systems with lensmodel. SIS + γ are the best models in both cases, which are in agreement with literature. SDSS1155+6346 model shows a large shear, due to the presence of MaxBCG J178.81693+63.83446 cluster. We follow Mediavilla et al. 2011, modeling the accretion disk as a Gaussian intensity profile I(R) ∝ exp(-R^{2}/2r_{s}^{2}), with r_s(λ) ∝ λ^{p}, where r_{s} is the accretion disk size and p is the power law related to the temperature of the disk p = 1/β. We estimate the probability of r_{s} and p using the measured microlensing magnification with linear and logarithmic priors on r_{s}. We found within 1σ of uncertainty, sizes between 3 and 15 light days and temperature profiles values between 1 and 1.2. These values are in agreement with the literature and Shakura & Sunyaev (1973) prediction. We acknowledge to FONDECYT 1120741 and Centro de Astrofísica, Universidad de Valparaíso.
The advantages of using a Lucky Imaging camera for observations of microlensing events

NASA Astrophysics Data System (ADS)

Sajadian, Sedighe; Rahvar, Sohrab; Dominik, Martin; Hundertmark, Markus

2016-05-01

In this work, we study the advantages of using a Lucky Imaging camera for the observations of potential planetary microlensing events. Our aim is to reduce the blending effect and enhance exoplanet signals in binary lensing systems composed of an exoplanet and the corresponding parent star. We simulate planetary microlensing light curves based on present microlensing surveys and follow-up telescopes where one of them is equipped with a Lucky Imaging camera. This camera is used at the Danish 1.54-m follow-up telescope. Using a specific observational strategy, for an Earth-mass planet in the resonance regime, where the detection probability in crowded fields is smaller, Lucky Imaging observations improve the detection efficiency which reaches 2 per cent. Given the difficulty of detecting the signal of an Earth-mass planet in crowded-field imaging even in the resonance regime with conventional cameras, we show that Lucky Imaging can substantially improve the detection efficiency.
Amplification and polarization of supernovae by gravitational lensing

NASA Technical Reports Server (NTRS)

Schneider, P.; Wagoner, Robert V.

1987-01-01

The gravitational lensing of supernovae by individual masses which could comprise the dark matter is analyzed. Detailed predictions of the amplification and polarization are presented, including effects of a galactic environment. Their time dependence is produced by the expansion of the supernovae beam within the lens. The fraction of supernovae which might thus be identified as being lensed in surveys at proposed limiting magnitudes is estimated. These two effects could provide the only known unique signature of microlensing.
Discovery of a bright microlensing event with planetary features towards the Taurus region: a super-Earth planet

NASA Astrophysics Data System (ADS)

Nucita, A. A.; Licchelli, D.; De Paolis, F.; Ingrosso, G.; Strafella, F.; Katysheva, N.; Shugarov, S.

2018-05-01

The transient event labelled as TCP J05074264+2447555 recently discovered towards the Taurus region was quickly recognized to be an ongoing microlensing event on a source located at distance of only 700-800 pc from Earth. Here, we show that observations with high sampling rate close to the time of maximum magnification revealed features that imply the presence of a binary lens system with very low-mass ratio components. We present a complete description of the binary lens system, which host an Earth-like planet with most likely mass of 9.2 ± 6.6 M⊕. Furthermore, the source estimated location and detailed Monte Carlo simulations allowed us to classify the event as due to the closest lens system, being at a distance of ≃380 pc and mass ≃0.25 M⊙.
Gravitational Microlensing Observations of Two New Exoplanets Using the Deep Impact High Resolution Instrument

NASA Astrophysics Data System (ADS)

Barry, Richard K.; Bennett, D. P.; Klaasen, K.; Becker, A. C.; Christiansen, J.; Albrow, M.

2014-01-01

We have worked to characterize two exoplanets newly detected from the ground: OGLE-2012-BLG-0406 and OGLE-2012-BLG-0838, using microlensing observations of the Galactic Bulge recently obtained by NASA’s Deep Impact (DI) spacecraft, in combination with ground data. These observations of the crowded Bulge fields from Earth and from an observatory at a distance of ~1 AU have permitted the extraction of a microlensing parallax signature - critical for breaking exoplanet model degeneracies. For this effort, we used DI’s High Resolution Instrument, launched with a permanent defocus aberration due to an error in cryogenic testing. We show how the effects of a very large, chromatic PSF can be reduced in differencing photometry. We also compare two approaches to differencing photometry - one of which employs the Bramich algorithm and another using the Fruchter & Hook drizzle algorithm.
Chromaticity of gravitational microlensing events

NASA Astrophysics Data System (ADS)

Han, Cheongho; Park, Seong-Hong; Jeong, Jang-Hae

2000-07-01

In this paper, we investigate the colour changes of gravitational microlensing events caused by the two different mechanisms of differential amplification for a limb-darkened extended source and blending. From this investigation, we find that the colour changes of limb-darkened extended source events (colour curves) have dramatically different characteristics depending on whether the lens transits the source star or not. We show that for a source transit event, the lens proper motion can be determined by simply measuring the turning time of the colour curve instead of fitting the overall colour or light curves. We also find that even for a very small fraction of blended light, the colour changes induced by blending are equivalent to those induced by limb darkening, causing serious distortion in the observed colour curve. Therefore, to obtain useful information about the lens and source star from the colour curve of an event, it will be essential to correct for blending. We discuss various methods of blending correction.
Orbital synchronization capture of two binaries emitting gravitational waves

NASA Astrophysics Data System (ADS)

Seto, Naoki

2018-03-01

We study the possibility of orbital synchronization capture for a hierarchical quadrupole stellar system composed by two binaries emitting gravitational waves. Based on a simple model including the mass transfer for white dwarf binaries, we find that the capture might be realized for inter-binary distances less than their gravitational wavelength. We also discuss related intriguing phenomena such as a parasitic relation between the coupled white dwarf binaries and significant reductions of gravitational and electromagnetic radiations.
The local nanohertz gravitational-wave landscape from supermassive black hole binaries

NASA Astrophysics Data System (ADS)

Mingarelli, Chiara M. F.; Lazio, T. Joseph W.; Sesana, Alberto; Greene, Jenny E.; Ellis, Justin A.; Ma, Chung-Pei; Croft, Steve; Burke-Spolaor, Sarah; Taylor, Stephen R.

2017-12-01

Supermassive black hole binary systems form in galaxy mergers and reside in galactic nuclei with large and poorly constrained concentrations of gas and stars. These systems emit nanohertz gravitational waves that will be detectable by pulsar timing arrays. Here we estimate the properties of the local nanohertz gravitational-wave landscape that includes individual supermassive black hole binaries emitting continuous gravitational waves and the gravitational-wave background that they generate. Using the 2 Micron All-Sky Survey, together with galaxy merger rates from the Illustris simulation project, we find that there are on average 91 ± 7 continuous nanohertz gravitational-wave sources, and 7 ± 2 binaries that will never merge, within 225 Mpc. These local unresolved gravitational-wave sources can generate a departure from an isotropic gravitational-wave background at a level of about 20 per cent, and if the cosmic gravitational-wave background can be successfully isolated, gravitational waves from at least one local supermassive black hole binary could be detected in 10 years with pulsar timing arrays.
A PLANETARY LENSING FEATURE IN CAUSTIC-CROSSING HIGH-MAGNIFICATION MICROLENSING EVENTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chung, Sun-Ju; Hwang, Kyu-Ha; Ryu, Yoon-Hyun

Current microlensing follow-up observations focus on high-magnification events because of the high efficiency of planet detection. However, central perturbations of high-magnification events caused by a planet can also be produced by a very close or a very wide binary companion, and the two kinds of central perturbations are not generally distinguished without time consuming detailed modeling (a planet-binary degeneracy). Hence, it is important to resolve the planet-binary degeneracy that occurs in high-magnification events. In this paper, we investigate caustic-crossing high-magnification events caused by a planet and a wide binary companion. From this investigation, we find that because of the differentmore » magnification excess patterns inside the central caustics induced by the planet and the binary companion, the light curves of the caustic-crossing planetary-lensing events exhibit a feature that is discriminated from those of the caustic-crossing binary-lensing events, and the feature can be used to immediately distinguish between the planetary and binary companions. The planetary-lensing feature appears in the interpeak region between the two peaks of the caustic-crossings. The structure of the interpeak region for the planetary-lensing events is smooth and convex or boxy, whereas the structure for the binary-lensing events is smooth and concave. We also investigate the effect of a finite background source star on the planetary-lensing feature in the caustic-crossing high-magnification events. From this, we find that the convex-shaped interpeak structure appears in a certain range that changes with the mass ratio of the planet to the planet-hosting star.« less
Spectroscopic Characterisation of Microlensing Events: Towards a New Interpretation of OGLE-2011-BLG-0417

NASA Technical Reports Server (NTRS)

Santerne, A.; Beaulieu, J.-P.; Rojas Ayala, B.; Boisse, I.; Schlawin, E.; Almenara, J.-M.; Batista, V.; Bennett, D.; Diaz, R. F.; Figueira, P.;

2016-01-01

The microlensing event OGLE-2011-BLG-0417 is an exceptionally bright lens binary that was predicted to present radial velocity variation at the level of several km s1. Pioneer radial velocity follow-up observations with the UVES spectrograph at the ESOVLT of this system clearly ruled out the large radial velocity variation, leaving a discrepancy between the observation and the prediction. In this paper, we further characterise the microlensing system by analysing its spectral energy distribution (SED) derived using the UVES spectrum and new observations with the ARCoIRIS (CTIO) near-infrared spectrograph and the Keck adaptive optics instrumentNIRC2 in the J, H, and Ks-bands. We determine the mass and distance of the stars independently from the microlensing modelling. We find that the SED is compatible with a giant star in the Galactic bulge and a foreground star with a mass of 0.94 +/- 0.09 M solar mass at a distance of 1.07 +/- 0.24 kpc. We find that this foreground star is likely the lens. Its parameters are not compatible with the onespreviously reported in the literature (0.52 +/- 0.04 M solar mass at 0.95 +/- 0.06 kpc), based on the microlensing light curve. A thoughtful reanalysis of the microlensing event is mandatory to fully understand the reason of this new discrepancy. More importantly, this paper demonstrates that spectroscopic follow-up observations of microlensing events are possible and provide independent constraints on the parameters of the lens and source stars, hence breaking some degeneracies in the analysis. UV-to-NIR low-resolution spectrographs like X-shooter (ESOVLT) could substantially contribute to this follow-up efforts, with magnitude limits above all microlensing events detected so far.

OGLE-2016-BLG-1266: A Probable Brown Dwarf/Planet Binary at the Deuterium Fusion Limit

NASA Astrophysics Data System (ADS)

Albrow, M. D.; Yee, J. C.; Udalski, A.; Calchi Novati, S.; Carey, S.; Henderson, C. B.; Beichman, C.; Bryden, G.; Gaudi, B. S.; Shvartzvald, Y.; Spitzer team; Szymański, M. K.; Mróz, P.; Skowron, J.; Poleski, R.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Pawlak, M.; OGLE Collaboration; Chung, S.-J.; Gould, A.; Han, C.; Hwang, K.-H.; Jung, Y. K.; Ryu, Y.-H.; Shin, I.-G.; Zhu, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.; KMTNet Collaboration

2018-05-01

We report the discovery, via the microlensing method, of a new very low mass binary system. By combining measurements from Earth and from the Spitzer telescope in Earth-trailing orbit, we are able to measure the microlensing parallax of the event, and we find that the lens likely consists of a (12.0 ± 0.6)M J + (15.7 ± 1.5)M J super-Jupiter/brown dwarf pair. The binary is located at a distance of 3.08 ± 0.18 kpc in the Galactic plane, and the components have a projected separation of 0.43 ± 0.03 au. Two alternative solutions with much lower likelihoods are also discussed, an 8M J and 6M J model and a 90M J and 70M J model. If all photometric measurements were independent and Gaussian distributed with known variances, these alternative solutions would be formally disfavored at the 3σ and 5σ levels. We show how the more massive of these models could be tested with future direct imaging.
Binary Source Microlensing Event OGLE-2016-BLG-0733: Interpretation of a Long-Term Asymmetric Perturbation

NASA Technical Reports Server (NTRS)

Jung, Y. K.; Udalski, A.; Yee, J. C.; Sumi, T.; Gould, A.; Han, C.; Albrow, M. D.; Lee, C.-U.; Bennett, D. P.; Suzuki, D.

2017-01-01

In the process of analyzing an observed light curve, one often confronts various scenarios that can mimic the planetary signals causing difficulties in the accurate interpretation of the lens system. In this paper, we present the analysis of the microlensing event OGLE-2016-BLG-0733. The light curve of the event shows a long-term asymmetric perturbation that would appear to be due to a planet. From the detailed modeling of the lensing light curve, however, we find that the perturbation originates from the binarity of the source rather than the lens. This result demonstrates that binary sources with roughly equal-luminosity components can mimic long-term perturbations induced by planets with projected separations near the Einstein ring. The result also represents the importance of the consideration of various interpretations in planet-like perturbations and of high-cadence observations for ensuring the unambiguous detection of the planet.
Structure formation and microlensing with axion miniclusters

NASA Astrophysics Data System (ADS)

Fairbairn, Malcolm; Marsh, David J. E.; Quevillon, Jérémie; Rozier, Simon

2018-04-01

If the symmetry breaking responsible for axion dark matter production occurs during the radiation-dominated epoch in the early Universe, then this produces large amplitude perturbations that collapse into dense objects known as axion miniclusters. The characteristic minicluster mass, M0, is set by the mass inside the horizon when axion oscillations begin. For the QCD axion M0˜10-10 M⊙, however, for an axionlike particle, M0 can approach M⊙ or higher. Using the Press-Schechter formalism we compute the mass function of halos formed by hierarchical structure formation from these seeds. We compute the concentrations and collapse times of these halos and show that they can grow to be as massive as 1 06M0. Within the halos, miniclusters likely remain tightly bound, and we compute their gravitational microlensing signal taking the fraction of axion dark matter collapsed into miniclusters, fMC, as a free parameter. A large value of fMC severely weakens constraints on axion scenarios from direct detection experiments. We take into account the non-Gaussian distribution of sizes of miniclusters and determine how this affects the number of microlensing events. We develop the tools to consider microlensing by an extended mass function of nonpointlike objects, and we use microlensing data to place the first observational constraints on fMC. This opens a new window for the potential discovery of the axion.
Searching for the QCD Axion with Gravitational Microlensing

NASA Astrophysics Data System (ADS)

Fairbairn, Malcolm; Marsh, David J. E.; Quevillon, Jérémie

2017-07-01

The phase transition responsible for axion dark matter (DM) production can create large amplitude isocurvature perturbations, which collapse into dense objects known as axion miniclusters. We use microlensing data from the EROS survey and from recent observations with the Subaru Hyper Suprime Cam to place constraints on the minicluster scenario. We compute the microlensing event rate for miniclusters, treating them as spatially extended objects. Using the published bounds on the number of microlensing events, we bound the fraction of DM collapsed into miniclusters fMC. For an axion with temperature-dependent mass consistent with the QCD axion, we find fMC<0.083 (ma/100 μ eV )0.12 , which represents the first observational constraint on the minicluster fraction. We forecast that a high-efficiency observation of around ten nights with Subaru would be sufficient to constrain fMC≲0.004 over the entire QCD axion mass range. We make various approximations to derive these constraints, and dedicated analyses by the observing teams of EROS and Subaru are necessary to confirm our results. If accurate theoretical predictions for fMC can be made in the future, then microlensing can be used to exclude or discover the QCD axion. Further details of our computations are presented in a companion paper [M. Fairbairn, D. J. E. Marsh, J. Quevillon, and S. Rozier (to be published)].

Time Delay in Microlensing Event

NASA Image and Video Library

2015-04-14

This plot shows data obtained from NASA's Spitzer Space Telescope and the Optical Gravitational Lensing Experiment, or OGLE, telescope located in Chile, during a "microlensing" event. Microlensing events occur when one star passes another, and the gravity of the foreground star causes the distant star's light to magnify and brighten. This magnification is evident in the plot, as both Spitzer and OGLE register an increase in the star's brightness. If the foreground star is circled by a planet, the planet's gravity can alter the magnification over a shorter period, seen in the plot in the form of spikes and a dip. The great distance between Spitzer, in space, and OGLE, on the ground, meant that Spitzer saw this particular microlensing event before OGLE. The offset in the timing can be used to measure the distance to the planet. In this case, the planet, called OGLE-2014-BLG-0124L, was found to be 13,000 light-years away, near the center of our Milky Way galaxy. The finding was the result of fortuitous timing because Spitzer's overall program to observe microlensing events was only just starting up in the week before the planet's effects were visible from Spitzer's vantage point. While Spitzer sees infrared light of 3.6 microns in wavelength, OGLE sees visible light of 0.8 microns. http://photojournal.jpl.nasa.gov/catalog/PIA19331
Interpreting the Strongly Lensed Supernova iPTF16geu: Time Delay Predictions, Microlensing, and Lensing Rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

More, Anupreeta; Oguri, Masamune; More, Surhud

2017-02-01

We present predictions for time delays between multiple images of the gravitationally lensed supernova, iPTF16geu, which was recently discovered from the intermediate Palomar Transient Factory (iPTF). As the supernova is of Type Ia where the intrinsic luminosity is usually well known, accurately measured time delays of the multiple images could provide tight constraints on the Hubble constant. According to our lens mass models constrained by the Hubble Space Telescope F814W image, we expect the maximum relative time delay to be less than a day, which is consistent with the maximum of 100 hr reported by Goobar et al. but placesmore » a stringent upper limit. Furthermore, the fluxes of most of the supernova images depart from expected values suggesting that they are affected by microlensing. The microlensing timescales are small enough that they may pose significant problems to measure the time delays reliably. Our lensing rate calculation indicates that the occurrence of a lensed SN in iPTF is likely. However, the observed total magnification of iPTF16geu is larger than expected, given its redshift. This may be a further indication of ongoing microlensing in this system.« less
New Self-lensing Models of the Small Magellanic Cloud: Can Gravitational Microlensing Detect Extragalactic Exoplanets?

NASA Astrophysics Data System (ADS)

Mróz, Przemek; Poleski, Radosław

2018-04-01

We use three-dimensional distributions of classical Cepheids and RR Lyrae stars in the Small Magellanic Cloud (SMC) to model the stellar density distribution of a young and old stellar population in that galaxy. We use these models to estimate the microlensing self-lensing optical depth to the SMC, which is in excellent agreement with the observations. Our models are consistent with the total stellar mass of the SMC of about 1.0× {10}9 {M}ȯ under the assumption that all microlensing events toward this galaxy are caused by self-lensing. We also calculate the expected event rates and estimate that future large-scale surveys, like the Large Synoptic Survey Telescope (LSST), will be able to detect up to a few dozen microlensing events in the SMC annually. If the planet frequency in the SMC is similar to that in the Milky Way, a few extragalactic planets can be detected over the course of the LSST survey, provided significant changes in the SMC observing strategy are devised. A relatively small investment of LSST resources can give us a unique probe of the population of extragalactic exoplanets.
One or more bound planets per Milky Way star from microlensing observations.

PubMed

Cassan, A; Kubas, D; Beaulieu, J-P; Dominik, M; Horne, K; Greenhill, J; Wambsganss, J; Menzies, J; Williams, A; Jørgensen, U G; Udalski, A; Bennett, D P; Albrow, M D; Batista, V; Brillant, S; Caldwell, J A R; Cole, A; Coutures, Ch; Cook, K H; Dieters, S; Prester, D Dominis; Donatowicz, J; Fouqué, P; Hill, K; Kains, N; Kane, S; Marquette, J-B; Martin, R; Pollard, K R; Sahu, K C; Vinter, C; Warren, D; Watson, B; Zub, M; Sumi, T; Szymański, M K; Kubiak, M; Poleski, R; Soszynski, I; Ulaczyk, K; Pietrzyński, G; Wyrzykowski, L

2012-01-11

Most known extrasolar planets (exoplanets) have been discovered using the radial velocity or transit methods. Both are biased towards planets that are relatively close to their parent stars, and studies find that around 17-30% (refs 4, 5) of solar-like stars host a planet. Gravitational microlensing, on the other hand, probes planets that are further away from their stars. Recently, a population of planets that are unbound or very far from their stars was discovered by microlensing. These planets are at least as numerous as the stars in the Milky Way. Here we report a statistical analysis of microlensing data (gathered in 2002-07) that reveals the fraction of bound planets 0.5-10 AU (Sun-Earth distance) from their stars. We find that 17(+6)(-9)% of stars host Jupiter-mass planets (0.3-10 M(J), where M(J) = 318 M(⊕) and M(⊕) is Earth's mass). Cool Neptunes (10-30 M(⊕)) and super-Earths (5-10 M(⊕)) are even more common: their respective abundances per star are 52(+22)(-29)% and 62(+35)(-37)%. We conclude that stars are orbited by planets as a rule, rather than the exception.
Augmenting WFIRST Microlensing with a Ground-Based Telescope Network

NASA Astrophysics Data System (ADS)

Zhu, Wei; Gould, Andrew

2016-06-01

Augmenting the Wide Field Infrared Survey Telescope (WFIRST) microlensing campaigns with intensive observations from a ground-based network of wide-field survey telescopes would have several major advantages. First, it would enable full two-dimensional (2-D) vector microlens parallax measurements for a substantial fraction of low-mass lenses as well as planetary and binary events that show caustic crossing features. For a significant fraction of the free-floating planet (FFP) events and all caustic-crossing planetary/binary events, these 2-D parallax measurements directly lead to complete solutions (mass, distance, transverse velocity) of the lens object (or lens system). For even more events, the complementary ground-based observations will yield 1-D parallax measurements. Together with the 1-D parallaxes from WFIRST alone, they can probe the entire mass range M > M_Earth. For luminous lenses, such 1-D parallax measurements can be promoted to complete solutions (mass, distance, transverse velocity) by high-resolution imaging. This would provide crucial information not only about the hosts of planets and other lenses, but also enable a much more precise Galactic model. Other benefits of such a survey include improved understanding of binaries (particularly with low mass primaries), and sensitivity to distant ice-giant and gas-giant companions of WFIRST lenses that cannot be detected by WFIRST itself due to its restricted observing windows. Existing ground-based microlensing surveys can be employed if WFIRST is pointed at lower-extinction fields than is currently envisaged. This would come at some cost to the event rate. Therefore the benefits of improved characterization of lenses must be weighed against these costs.
Effects of Accretion Disks on Spins and Eccentricities of Binaries, and Implications for Gravitational Waves

NASA Technical Reports Server (NTRS)

Baker, John

2012-01-01

Effects of accretion disks on spins and eccentricities of binaries, and implications for gravitational waves. John Baker Space-based gravitational wave observations will allow exquisitely precise measurements of massive black hole binary properties. Through several recently suggested processes, these properties may depend on interactions with accretion disks through the merger process. I will discuss ways that accretion may influence those binary properties which may be probed by gravitational-wave observations.
Discovering Extrasolar Planets with Microlensing Surveys

NASA Astrophysics Data System (ADS)

Wambsganss, J.

2016-06-01

An astronomical survey is commonly understood as a mapping of a large region of the sky, either photometrically (possibly in various filters/wavelength ranges) or spectroscopically. Often, catalogs of objects are produced/provided as the main product or a by-product. However, with the advent of large CCD cameras and dedicated telescopes with wide-field imaging capabilities, it became possible in the early 1990s, to map the same region of the sky over and over again. In principle, such data sets could be combined to get very deep stacked images of the regions of interest. However, I will report on a completely different use of such repeated maps: Exploring the time domain for particular kinds of stellar variability, namely microlens-induced magnifications in search of exoplanets. Such a time-domain microlensing survey was originally proposed by Bohdan Paczynski in 1986 in order to search for dark matter objects in the Galactic halo. Only a few years later three teams started this endeavour. I will report on the history and current state of gravitational microlensing surveys. By now, routinely 100 million stars in the Galactic Bulge are monitored a few times per week by so-called survey teams. All stars with constant apparent brightness and those following known variability patterns are filtered out in order to detect the roughly 2000 microlensing events per year which are produced by stellar lenses. These microlensing events are identified "online" while still in their early phases and then monitored with much higher cadence by so-called follow-up teams. The most interesting of such events are those produced by a star-plus-planet lens. By now of order 30 exoplanets have been discovered by these combined microlensing surveys. Microlensing searches for extrasolar planets are complementary to other exoplanet search techniques. There are two particular advantages: The microlensing method is sensitive down to Earth-mass planets even with ground-based telecopes, and it can be easily used to determine the global abundance of planets in the Milky Way. Recent results of these microlensing surveys are presented and discussed, e. g. the discovery that on average every Milky Way star has at least one planet of Neptune mass or higher.
A companion on the planet/brown dwarf mass boundary on a wide orbit discovered by gravitational microlensing

NASA Astrophysics Data System (ADS)

Poleski, R.; Udalski, A.; Bond, I. A.; Beaulieu, J. P.; Clanton, C.; Gaudi, S.; Szymański, M. K.; Soszyński, I.; Pietrukowicz, P.; Kozłowski, Szymon; Skowron, J.; Wyrzykowski, Ł.; Ulaczyk, K.; Bennett, D. P.; Sumi, T.; Suzuki, D.; Rattenbury, N. J.; Koshimoto, N.; Abe, F.; Asakura, Y.; Barry, R. K.; Bhattacharya, A.; Donachie, M.; Evans, P.; Fukui, A.; Hirao, Y.; Itow, Y.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Ranc, C.; Saito, To.; Sharan, A.; Sullivan, D. J.; Tristram, P. J.; Yamada, T.; Yamada, T.; Yonehara, A.; Batista, V.; Marquette, J. B.

2017-08-01

We present the discovery of a substellar companion to the primary host lens in the microlensing event MOA-2012-BLG-006. The companion-to-host mass ratio is 0.016, corresponding to a companion mass of ≈8 MJup(M∗/ 0.5 M⊙). Thus, the companion is either a high-mass giant planet or a low-mass brown dwarf, depending on the mass of the primary M∗. The companion signal was separated from the peak of the primary event by a time that was as much as four times longer than the event timescale. We therefore infer a relatively large projected separation of the companion from its host of ≈10 au(M∗/ 0.5 M⊙)1 / 2 for a wide range (3-7 kpc) of host star distances from the Earth. We also challenge a previous claim of a planetary companion to the lens star in microlensing event OGLE-2002-BLG-045.
Microlensing of Relativistic Knots in the Quasar HE 1104-1805 AB

NASA Astrophysics Data System (ADS)

Schechter, Paul L.; Udalski, A.; Szymański, M.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Woźniak, P.; Żebruń, K.; Szewczyk, O.; Wyrzykowski, Ł.

2003-02-01

We present 3 years of photometry of the ``Double Hamburger'' lensed quasar, HE 1104-1805 AB, obtained on 102 separate nights using the Optical Gravitational Lensing Experiment 1.3 m telescope. Both the A and B images show variations, but with substantial differences in the light curves at all time delays. At the 310 day delay reported by Wisotzki and collaborators, the difference light curve has an rms amplitude of 0.060 mag. The structure functions for the A and B images are quite different, with image A more than twice as variable as image B (a factor of 4 in structure function) on timescales of less than a month. Adopting microlensing as a working hypothesis for the uncorrelated variability, the short timescale argues for the relativistic motion of one or more components of the source. We argue that the small amplitude of the fluctuations is due to the finite size of the source with respect to the microlenses.
Hubble Finds Planet Orbiting Pair of Stars

NASA Image and Video Library

2017-12-08

Two's company, but three might not always be a crowd — at least in space. Astronomers using NASA's Hubble Space Telescope, and a trick of nature, have confirmed the existence of a planet orbiting two stars in the system OGLE-2007-BLG-349, located 8,000 light-years away towards the center of our galaxy. The planet orbits roughly 300 million miles from the stellar duo, about the distance from the asteroid belt to our sun. It completes an orbit around both stars roughly every seven years. The two red dwarf stars are a mere 7 million miles apart, or 14 times the diameter of the moon's orbit around Earth. The Hubble observations represent the first time such a three-body system has been confirmed using the gravitational microlensing technique. Gravitational microlensing occurs when the gravity of a foreground star bends and amplifies the light of a background star that momentarily aligns with it. The particular character of the light magnification can reveal clues to the nature of the foreground star and any associated planets. The three objects were discovered in 2007 by an international collaboration of five different groups: Microlensing Observations in Astrophysics (MOA), the Optical Gravitational Lensing Experiment (OGLE), the Microlensing Follow-up Network (MicroFUN), the Probing Lensing Anomalies Network (PLANET), and the Robonet Collaboration. These ground-based observations uncovered a star and a planet, but a detailed analysis also revealed a third body that astronomers could not definitively identify. Image caption: This artist's illustration shows a gas giant planet circling a pair of red dwarf stars in the system OGLE-2007-BLG-349, located 8,000 light-years away. The Saturn-mass planet orbits roughly 300 million miles from the stellar duo. The two red dwarf stars are 7 million miles apart. Credit: NASA, ESA, and G. Bacon (STScI) Read more: go.nasa.gov/2dcfMns NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram
First detections of gravitational waves emitted from binary black hole mergers

NASA Astrophysics Data System (ADS)

Reitze, D. H.

2017-11-01

The LIGO Scientific Collaboration and the Virgo Collaboration carried out the inaugural ‘O1’ observing run from September 12, 2015 through January 19, 2016 using the newly commissioned Advanced LIGO interferometers located in Hanford,WAand Livingston, LA. During theO1 run and the O2 run currently underway, three definitive detections of gravitational waves have occurred, each produced during the mergers of binary stellar mass black holes. A fourth candidate gravitational-wave event was identified, also likely produced from a binary black hole merger. The detected gravitational waveforms allow for the inference of the intrinsic astrophysical parameters of the merging binary systems, as well as the resulting black hole produced by the mergers. The first detect detections of gravitational waves confirm the existence of binary black hole systems and have profound implications for astrophysics using gravitational waves as a new and powerful probe of the universe.
Simulating Gravitational Radiation from Binary Black Holes Mergers as LISA Sources

NASA Technical Reports Server (NTRS)

Baker, John

2005-01-01

A viewgraph presentation on the simulation of gravitational waves from Binary Massive Black Holes with LISA observations is shown. The topics include: 1) Massive Black Holes (MBHs); 2) MBH Binaries; 3) Gravitational Wavws from MBH Binaries; 4) Observing with LISA; 5) How LISA sees MBH binary mergers; 6) MBH binary inspirals to LISA; 7) Numerical Relativity Simulations; 8) Numerical Relativity Challenges; 9) Recent Successes; 10) Goddard Team; 11) Binary Black Hole Simulations at Goddard; 12) Goddard Recent Advances; 13) Baker, et al.:GSFC; 13) Starting Farther Out; 14) Comparing Initial Separation; 15) Now with AMR; and 16) Conclusion.
Spitzer Microlens Measurement of a Massive Remnant in a Well-separated Binary

NASA Astrophysics Data System (ADS)

Shvartzvald, Y.; Udalski, A.; Gould, A.; Han, C.; Bozza, V.; Friedmann, M.; Hundertmark, M.; and; Beichman, C.; Bryden, G.; Calchi Novati, S.; Carey, S.; Fausnaugh, M.; Gaudi, B. S.; Henderson, C. B.; Kerr, T.; Pogge, R. W.; Varricatt, W.; Wibking, B.; Yee, J. C.; Zhu, W.; Spitzer Team; Poleski, R.; Pawlak, M.; Szymański, M. K.; Skowron, J.; Mróz, P.; Kozłowski, S.; Wyrzykowski, Ł.; Pietrukowicz, P.; Pietrzyński, G.; Soszyński, I.; Ulaczyk, K.; OGLE Group; Choi, J.-Y.; Park, H.; Jung, Y. K.; Shin, I.-G.; Albrow, M. D.; Park, B.-G.; Kim, S.-L.; Lee, C.-U.; Cha, S.-M.; Kim, D.-J.; Lee, Y.; KMTNet Group; Maoz, D.; Kaspi, S.; Wise Group; Street, R. A.; Tsapras, Y.; Bachelet, E.; Dominik, M.; Bramich, D. M.; Horne, Keith; Snodgrass, C.; Steele, I. A.; Menzies, J.; Figuera Jaimes, R.; Wambsganss, J.; Schmidt, R.; Cassan, A.; Ranc, C.; Mao, S.; Dong, Subo; RoboNet; D'Ago, G.; Scarpetta, G.; Verma, P.; Jørgensen, U. G.; Kerins, E.; Skottfelt, J.; MiNDSTEp

2015-12-01

We report the detection and mass measurement of a binary lens OGLE-2015-BLG-1285La,b, with the more massive component having M1 > 1.35 M⊙ (80% probability). A main-sequence star in this mass range is ruled out by limits on blue light, meaning that a primary in this mass range must be a neutron star (NS) or black hole (BH). The system has a projected separation r⊥ = 6.1 ± 0.4 AU and lies in the Galactic bulge. These measurements are based on the “microlens parallax” effect, i.e., comparing the microlensing light curve as seen from Spitzer, which lay at 1.25 AU projected from Earth, to the light curves from four ground-based surveys, three in the optical and one in the near-infrared. Future adaptive optics imaging of the companion by 30 m class telescopes will yield a much more accurate measurement of the primary mass. This discovery both opens the path and defines the challenges to detecting and characterizing BHs and NSs in wide binaries, with either dark or luminous companions. In particular, we discuss lessons that can be applied to future Spitzer and Kepler K2 microlensing parallax observations.
Spitzer Opens New Path to Break Classic Degeneracy for Jupiter-mass Microlensing Planet OGLE-2017-BLG-1140Lb

NASA Astrophysics Data System (ADS)

Calchi Novati, S.; Skowron, J.; Jung, Y. K.; Beichman, C.; Bryden, G.; Carey, S.; Gaudi, B. S.; Henderson, C. B.; Shvartzvald, Y.; Yee, J. C.; Zhu, W.; Spitzer Team; Udalski, A.; Szymański, M. K.; Mróz, P.; Poleski, R.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Pawlak, M.; Rybicki, K.; Iwanek, P.; OGLE Collaboration; Albrow, M. D.; Chung, S.-J.; Gould, A.; Han, C.; Hwang, K.-H.; Ryu, Y.-H.; Shin, I.-G.; Zang, W.; Cha, S.-M.; Kim, D.-J.; Kim, H.-W.; Kim, S.-L.; Lee, C.-U.; Lee, D.-J.; Lee, Y.; Park, B.-G.; Pogge, R. W.; KMTNet Collaboration

2018-06-01

We analyze the combined Spitzer and ground-based data for OGLE-2017-BLG-1140 and show that the event was generated by a Jupiter-class ({m}p≃ 1.6 {M}{{J}{{u}}{{p}}}) planet orbiting a mid-late M dwarf (M≃ 0.2 {M}ȯ ) that lies {D}LS}≃ 1.0 {kpc} in the foreground of the microlensed Galactic-bar source star. The planet–host projected separation is {a}\\perp ≃ 1.0 {au}, i.e., well beyond the snow line. By measuring the source proper motion {{\\boldsymbol{μ }}}s from ongoing long-term OGLE imaging and combining this with the lens-source relative proper motion {{\\boldsymbol{μ }}}rel} derived from the microlensing solution, we show that the lens proper motion {{\\boldsymbol{μ }}}l={{\\boldsymbol{μ }}}rel}+{{\\boldsymbol{μ }}}s is consistent with the lens lying in the Galactic disk, although a bulge lens is not ruled out. We show that while the Spitzer and ground-based data are comparably well fitted by planetary (i.e., binary-lens (2L1S)) and binary-source (1L2S) models, the combination of Spitzer and ground-based data decisively favors the planetary model. This is a new channel to resolve the 2L1S/1L2S degeneracy, which can be difficult to break in some cases.
Bayesian analysis of caustic-crossing microlensing events

NASA Astrophysics Data System (ADS)

Cassan, A.; Horne, K.; Kains, N.; Tsapras, Y.; Browne, P.

2010-06-01

Aims: Caustic-crossing binary-lens microlensing events are important anomalous events because they are capable of detecting an extrasolar planet companion orbiting the lens star. Fast and robust modelling methods are thus of prime interest in helping to decide whether a planet is detected by an event. Cassan introduced a new set of parameters to model binary-lens events, which are closely related to properties of the light curve. In this work, we explain how Bayesian priors can be added to this framework, and investigate on interesting options. Methods: We develop a mathematical formulation that allows us to compute analytically the priors on the new parameters, given some previous knowledge about other physical quantities. We explicitly compute the priors for a number of interesting cases, and show how this can be implemented in a fully Bayesian, Markov chain Monte Carlo algorithm. Results: Using Bayesian priors can accelerate microlens fitting codes by reducing the time spent considering physically implausible models, and helps us to discriminate between alternative models based on the physical plausibility of their parameters.
Simulations of binary black hole mergers

NASA Astrophysics Data System (ADS)

Lovelace, Geoffrey

2017-01-01

Advanced LIGO's observations of merging binary black holes have inaugurated the era of gravitational wave astronomy. Accurate models of binary black holes and the gravitational waves they emit are helping Advanced LIGO to find as many gravitational waves as possible and to learn as much as possible about the waves' sources. These models require numerical-relativity simulations of binary black holes, because near the time when the black holes merge, all analytic approximations break down. Following breakthroughs in 2005, many research groups have built numerical-relativity codes capable of simulating binary black holes. In this talk, I will discuss current challenges in simulating binary black holes for gravitational-wave astronomy, and I will discuss the tremendous progress that has already enabled such simulations to become an essential tool for Advanced LIGO.
Galactic Distribution of Planets from Spitzer Microlens Parallaxes

NASA Astrophysics Data System (ADS)

Gould, Andrew; Carey, Sean; Yee, Jennifer

2014-12-01

We will measure the 'microlens parallaxes' of about 120 microlensing events that peak during Spitzer's 'bulge window' (2015 Jun 09 - Jul 19), by comparing simultaneous Spitzer and ground-based microlensing lightcurves, making use of Spitzer's location about 1 AU from Earth. These measurements will enable mass and distance measurements of about 4 microlensing planets. The ensemble of planet and non-planet distance measurements will yield the first probe of the Galactic distribution of planets Microlens planet mass measurements are very rare and have proved extremely interesting in every case. Microlensing identifies planets at and beyond the snowline, probing unique parameter space and providing vital information to constrain planet formation and migration theories. But the sample of ground-based microlens-parallax measurements is highly biased toward special systems. Spitzer would provide the first unbiased study. The same survey would provide a unique probe of brown dwarf binaries, and yield the first mass-based (not light-based) measurement of the stellar mass function (i.e., including dark objects such as black holes). A very successful 2014 'Pilot Program' demonstrates that this project is technically and scientifically viable. (As in the previous 'Pilot Program', we request zero day proprietary period.)
Search for gravitational waves from compact binary coalescence in LIGO and Virgo data from S5 and VSR1

NASA Astrophysics Data System (ADS)

Abadie, J.; Abbott, B. P.; Abbott, R.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Ajith, P.; Allen, B.; Allen, G.; Amador Ceron, E.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Antonucci, F.; Arain, M. A.; Araya, M.; Aronsson, M.; Arun, K. G.; Aso, Y.; Aston, S.; Astone, P.; Atkinson, D. E.; Aufmuth, P.; Aulbert, C.; Babak, S.; Baker, P.; Ballardin, G.; Ballinger, T.; Ballmer, S.; Barker, D.; Barnum, S.; Barone, F.; Barr, B.; Barriga, P.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Bauchrowitz, J.; Bauer, Th. S.; Behnke, B.; Beker, M. G.; Belletoile, A.; Benacquista, M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bigotta, S.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birindelli, S.; Biswas, R.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Blom, M.; Boccara, C.; Bock, O.; Bodiya, T. P.; Bondarescu, R.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Bose, S.; Bosi, L.; Bouhou, B.; Boyle, M.; Braccini, S.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Breyer, J.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Budzyński, R.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burguet–Castell, J.; Burmeister, O.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cain, J.; Calloni, E.; Camp, J. B.; Campagna, E.; Campsie, P.; Cannizzo, J.; Cannon, K. C.; Canuel, B.; Cao, J.; Capano, C.; Carbognani, F.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chalermsongsak, T.; Chalkley, E.; Charlton, P.; Chassande-Mottin, E.; Chelkowski, S.; Chen, Y.; Chincarini, A.; Christensen, N.; Chua, S. S. Y.; Chung, C. T. Y.; Clark, D.; Clark, J.; Clayton, J. H.; Cleva, F.; Coccia, E.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, R.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coulon, J.-P.; Coward, D.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Culter, R. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; D'Antonio, S.; Danzmann, K.; Das, K.; Dattilo, V.; Daudert, B.; Davier, M.; Davies, G.; Davis, A.; Daw, E. J.; Day, R.; Dayanga, T.; de Rosa, R.; Debra, D.; Degallaix, J.; Del Prete, M.; Dergachev, V.; Derosa, R.; Desalvo, R.; Devanka, P.; Dhurandhar, S.; di Fiore, L.; di Lieto, A.; di Palma, I.; di Paolo Emilio, M.; di Virgilio, A.; Díaz, M.; Dietz, A.; Donovan, F.; Dooley, K. L.; Doomes, E. E.; Dorsher, S.; Douglas, E. S. D.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Dueck, J.; Dumas, J.-C.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Ely, G.; Engel, R.; Etzel, T.; Evans, M.; Evans, T.; Fafone, V.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Ferrante, I.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Flaminio, R.; Flanigan, M.; Flasch, K.; Foley, S.; Forrest, C.; Forsi, E.; Fotopoulos, N.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Galimberti, M.; Gammaitoni, L.; Garofoli, J. A.; Garufi, F.; Gemme, G.; Genin, E.; Gennai, A.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gill, C.; Goetz, E.; Goggin, L. M.; González, G.; Goßler, S.; Gouaty, R.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Greverie, C.; Grosso, R.; Grote, H.; Grunewald, S.; Guidi, G. M.; Gustafson, E. K.; Gustafson, R.; Hage, B.; Hall, P.; Hallam, J. M.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Haughian, K.; Hayama, K.; Hayau, J.-F.; Hayler, T.; Heefner, J.; Heitmann, H.; Hello, P.; Heng, I. S.; Heptonstall, A.; Hewitson, M.; Hild, S.; Hirose, E.; Hoak, D.; Hodge, K. A.; Holt, K.; Hosken, D. J.; Hough, J.; Howell, E.; Hoyland, D.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh–Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Jaranowski, P.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kanner, J.; Katsavounidis, E.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kells, W.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, H.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kondrashov, V.; Kopparapu, R.; Koranda, S.; Kowalska, I.; Kozak, D.; Krause, T.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Królak, A.; Kuehn, G.; Kullman, J.; Kumar, R.; Kwee, P.; Landry, M.; Lang, M.; Lantz, B.; Lastzka, N.; Lazzarini, A.; Leaci, P.; Leong, J.; Leonor, I.; Leroy, N.; Letendre, N.; Li, J.; Li, T. G. F.; Lin, H.; Lindquist, P. E.; Lockerbie, N. A.; Lodhia, D.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lu, P.; Luan, J.; Lubiński, M.; Lucianetti, A.; Lück, H.; Lundgren, A.; Machenschalk, B.; Macinnis, M.; Mageswaran, M.; Mailand, K.; Majorana, E.; Mak, C.; Maksimovic, I.; Man, N.; Mandel, I.; Mandic, V.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Masserot, A.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIvor, G.; McKechan, D. J. A.; Meadors, G.; Mehmet, M.; Meier, T.; Melatos, A.; Melissinos, A. C.; Mendell, G.; Menéndez, D. F.; Mercer, R. A.; Merill, L.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Michel, C.; Milano, L.; Miller, J.; Minenkov, Y.; Mino, Y.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Mohan, M.; Mohanty, S. D.; Mohapatra, S. R. P.; Moraru, D.; Moreau, J.; Moreno, G.; Morgado, N.; Morgia, A.; Mors, K.; Mosca, S.; Moscatelli, V.; Mossavi, K.; Mours, B.; Mowlowry, C.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Müller-Ebhardt, H.; Munch, J.; Murray, P. G.; Nash, T.; Nawrodt, R.; Nelson, J.; Neri, I.; Newton, G.; Nishida, E.; Nishizawa, A.; Nocera, F.; Nolting, D.; Ochsner, E.; O'Dell, J.; Ogin, G. H.; Oldenburg, R. G.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Page, A.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Pardi, S.; Pareja, M.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patel, P.; Pathak, D.; Pedraza, M.; Pekowsky, L.; Penn, S.; Peralta, C.; Perreca, A.; Persichetti, G.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Plissi, M. V.; Poggiani, R.; Postiglione, F.; Prato, M.; Predoi, V.; Price, L. R.; Prijatelj, M.; Principe, M.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Quetschke, V.; Raab, F. J.; Rabeling, D. S.; Radke, T.; Radkins, H.; Raffai, P.; Rakhmanov, M.; Rankins, B.; Rapagnani, P.; Raymond, V.; Re, V.; Reed, C. M.; Reed, T.; Regimbau, T.; Reid, S.; Reitze, D. H.; Ricci, F.; Riesen, R.; Riles, K.; Roberts, P.; Robertson, N. A.; Robinet, F.; Robinson, C.; Robinson, E. L.; Rocchi, A.; Roddy, S.; Röver, C.; Rolland, L.; Rollins, J.; Romano, J. D.; Romano, R.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sakata, S.; Sakosky, M.; Salemi, F.; Sammut, L.; Sancho de La Jordana, L.; Sandberg, V.; Sannibale, V.; Santamaría, L.; Santostasi, G.; Saraf, S.; Sassolas, B.; Sathyaprakash, B. S.; Sato, S.; Satterthwaite, M.; Saulson, P. R.; Savage, R.; Schilling, R.; Schnabel, R.; Schofield, R.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Searle, A. C.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sergeev, A.; Shaddock, D.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sibley, A.; Siemens, X.; Sigg, D.; Singer, A.; Sintes, A. M.; Skelton, G.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, N. D.; Somiya, K.; Sorazu, B.; Speirits, F. C.; Sperandio, L.; Stein, A. J.; Stein, L. C.; Steinlechner, S.; Steplewski, S.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S.; Stroeer, A.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sung, M.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, J. R.; Taylor, R.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Thüring, A.; Titsler, C.; Tokmakov, K. V.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C.; Torrie, C. I.; Tournefier, E.; Travasso, F.; Traylor, G.; Trias, M.; Trummer, J.; Tseng, K.; Turner, L.; Ugolini, D.; Urbanek, K.; Vahlbruch, H.; Vaishnav, B.; Vajente, G.; Vallisneri, M.; van den Brand, J. F. J.; van den Broeck, C.; van der Putten, S.; van der Sluys, M. V.; van Veggel, A. A.; Vass, S.; Vaulin, R.; Vavoulidis, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Veltkamp, C.; Verkindt, D.; Vetrano, F.; Viceré, A.; Villar, A.; Vinet, J.-Y.; Vocca, H.; Vorvick, C.; Vyachanin, S. P.; Waldman, S. J.; Wallace, L.; Wanner, A.; Ward, R. L.; Was, M.; Wei, P.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wen, S.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Wilkinson, C.; Willems, P. A.; Williams, L.; Willke, B.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Woan, G.; Wooley, R.; Worden, J.; Yakushin, I.; Yamamoto, H.; Yamamoto, K.; Yeaton-Massey, D.; Yoshida, S.; Yu, P. P.; Yvert, M.; Zanolin, M.; Zhang, L.; Zhang, Z.; Zhao, C.; Zotov, N.; Zucker, M. E.; Zweizig, J.

2010-11-01

We report the results of the first search for gravitational waves from compact binary coalescence using data from the Laser Interferometer Gravitational-Wave Observatory and Virgo detectors. Five months of data were collected during the Laser Interferometer Gravitational-Wave Observatory’s S5 and Virgo’s VSR1 science runs. The search focused on signals from binary mergers with a total mass between 2 and 35M⊙. No gravitational waves are identified. The cumulative 90%-confidence upper limits on the rate of compact binary coalescence are calculated for nonspinning binary neutron stars, black hole-neutron star systems, and binary black holes to be 8.7×10-3yr-1L10-1, 2.2×10-3yr-1L10-1, and 4.4×10-4yr-1L10-1, respectively, where L10 is 1010 times the blue solar luminosity. These upper limits are compared with astrophysical expectations.
Gravitational Waves from Coalescing Binary Black Holes: Theoretical and Experimental Challenges

ScienceCinema

Damour, Thibault

2018-05-22

A network of ground-based interferometric gravitational wave detectors (LIGO/VIRGO/GEO/...) is currently taking data near its planned sensitivity. Coalescing black hole binaries are among the most promising, and most exciting, gravitational wave sources for these detectors. The talk will review the theoretical and experimental challenges that must be met in order to successfully detect gravitational waves from coalescing black hole binaries, and to be able to reliably measure the physical parameters of the source (masses, spins, ...).
Adventures in the microlensing cloud: Large datasets, eResearch tools, and GPUs

NASA Astrophysics Data System (ADS)

Vernardos, G.; Fluke, C. J.

2014-10-01

As astronomy enters the petascale data era, astronomers are faced with new challenges relating to storage, access and management of data. A shift from the traditional approach of combining data and analysis at the desktop to the use of remote services, pushing the computation to the data, is now underway. In the field of cosmological gravitational microlensing, future synoptic all-sky surveys are expected to bring the number of multiply imaged quasars from the few tens that are currently known to a few thousands. This inflow of observational data, together with computationally demanding theoretical modeling via the production of microlensing magnification maps, requires a new approach. We present our technical solutions to supporting the GPU-Enabled, High Resolution cosmological MicroLensing parameter survey (GERLUMPH). This extensive dataset for cosmological microlensing modeling comprises over 70 000 individual magnification maps and ˜106 related results. We describe our approaches to hosting, organizing, and serving ˜ 30 TB of data and metadata products. We present a set of online analysis tools developed with PHP, JavaScript and WebGL to support access and analysis of GELRUMPH data in a Web browser. We discuss our use of graphics processing units (GPUs) to accelerate data production, and we release the core of the GPU-D direct inverse ray-shooting code (Thompson et al., 2010, 2014) used to generate the magnification maps. All of the GERLUMPH data and tools are available online from http://gerlumph.swin.edu.au. This project made use of gSTAR, the GPU Supercomputer for Theoretical Astrophysical Research.

Photometric microlensing and stellar mass determination

NASA Astrophysics Data System (ADS)

Samadi, R.

Microlensing was suggested for stellar mass determination of nearby stars by several authors (e.g. Paczynski 1995 and Miralada-Escude 1996). There are two aspects in gravitational microlensing: photometry and astrometry. Here only the photometric aspect -i.e. magnification of a background source by a stellar lens- will be considered. The first study in this domain was done by Paczyński (1995). An attempt to investigate some observational constraints (Alard et al. 1996), takes its origin in this study. It will be shown here that blending of the source by the lens, not only induces a degeneracy which has been pointed out by Wozniak and Paczynski (1997) and can be removed by measuring the flux of the source outside the microlensing event, but also strongly reduces the photometric cross section as well as the duration of microlensing events. The expected number of events decreases strongly with blending. Blending effects can be reduced by selecting faint lens candidates. Unfortunately however, it is difficult to monitor a sufficient number of lens candidates per night, and restricting oneself to nearby and high proper motion objects would lead to a very small number of lens candidates. In the case of short duration events, the light curve must be sampled at short time intervals. When sampling daily, the condition is very strong and the expected rate of events very small. Observing from space would increase significantly the rate, but this gain is still insufficient. We conclude that the event rate will be very small and that the project does not seem to be feasible at least under current observing conditions and even in the near future.
Brown Dwarf Microlensing Diagram

NASA Image and Video Library

2016-11-10

For the first time, two space-based telescopes have teamed up with ground-based observatories to observe a microlensing event, a magnification of the light of a distant star due to the gravitational effects of an unseen object in the foreground. In this case, the cause of the microlensing event was a brown dwarf, dubbed OGLE-2015-BLG-1319, orbiting a star. In terms of mass, brown dwarfs fall somewhere between the size of the largest planets and the smallest stars. Curiously, scientists have found that, for stars roughly the mass of our sun, less than 1 percent have a brown dwarf orbiting within 3 AU (1 AU is the distance between Earth and the sun). This newly discovered brown dwarf may fall in that distance range. This microlensing event was observed by ground-based telescopes looking for these uncommon events, and subsequently seen by NASA's Spitzer and Swift space telescopes. As the diagram shows, Spitzer and Swift offer additional vantage points for viewing this chance alignment. While Swift orbits close to Earth, and saw (blue diamonds) essentially the same change in light that the ground-based telescopes measured (grey markers), Spitzer's location much farther away from Earth gave it a very different perspective on the event (red circles). In particular, Spitzer's vantage point resulted in a time lag in the microlensing event it observed, compared to what was seen by Swift and the ground-based telescope. This offset allowed astronomers to determine the distance to OGLE-2015-BLG-1319 as well as its mass: around 30-65 times that of Jupiter. http://photojournal.jpl.nasa.gov/catalog/PIA21077
Discovery and Mass Measurements of a Cold, 10-Earth Mass Planet and Its Host Star

NASA Technical Reports Server (NTRS)

Barry, Richard K.; Muraki, Y.; Han, C.; Bennett, D. P.; Gaudi, B. S.

2011-01-01

We present the discovery and mass measurement of the cold, low-mass planet MOA-2009-BLG-266Lb, made with the gravitational microlensing method. This planet has a mass of mp = 10.4 +/- M(Earth) and orbits a star of Mstar = 0.56 +/- 0.09 M(Sun) at a semi-major axis of a = 3.2 + 1.9/-0.5 AU, and an orbital period of 7.6 +7.7/-1.5 yrs. The planet and host star mass measurements are due to the measurement of the microlensing parallax effect. This measurement was primarily due to the orbital motion of the Earth, but the analysis also demonstrates the capability measure micro lensing parallax with the Deep Impact (or EPOXI) spacecraft in a Heliocentric orbit. The planet mass and orbital distance are similar to predictions for the critical core mass needed to accrete a substantial gaseous envelope, and thus may indicate that this planet is a failed gas giant. This and future microlensing detections will test planet formation theory predictions regarding the prevalence and masses of such planets
Gravitational waveforms from unequal-mass binaries with arbitrary spins under leading order spin-orbit coupling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tessmer, Manuel

This paper generalizes the structure of gravitational waves from orbiting spinning binaries under leading order spin-orbit coupling, as given in the work by Koenigsdoerffer and Gopakumar [Phys. Rev. D 71, 024039 (2005)] for single-spin and equal-mass binaries, to unequal-mass binaries and arbitrary spin configurations. The orbital motion is taken to be quasicircular and the fractional mass difference is assumed to be small against one. The emitted gravitational waveforms are given in analytic form.
Inferences about binary stellar populations using gravitational wave observations

NASA Astrophysics Data System (ADS)

Wysocki, Daniel; Gerosa, Davide; O'Shaughnessy, Richard; Belczynski, Krzysztof; Gladysz, Wojciech; Berti, Emanuele; Kesden, Michael; Holz, Daniel

2018-01-01

With the dawn of gravitational wave astronomy, enabled by the LIGO and Virgo interferometers, we now have a new window into the Universe. In the short time these detectors have been in use, multiple confirmed detections of gravitational waves from compact binary coalescences have been made. Stellar binary systems are one of the likely progenitors of the observed compact binary sources. If this is indeed the case, then we can use measured properties of these binary systems to learn about their progenitors. We will discuss the Bayesian framework in which we make these inferences, and results which include mass and spin distributions.
LISA verification binaries with updated distances from Gaia Data Release 2

NASA Astrophysics Data System (ADS)

Kupfer, T.; Korol, V.; Shah, S.; Nelemans, G.; Marsh, T. R.; Ramsay, G.; Groot, P. J.; Steeghs, D. T. H.; Rossi, E. M.

2018-06-01

Ultracompact binaries with orbital periods less than a few hours will dominate the gravitational wave signal in the mHz regime. Until recently, 10 systems were expected have a predicted gravitational wave signal strong enough to be detectable by the Laser Interferometer Space Antenna (LISA), the so-called `verification binaries'. System parameters, including distances, are needed to provide an accurate prediction of the expected gravitational wave strength to be measured by LISA. Using parallaxes from Gaia Data Release 2 we calculate signal-to-noise ratios (SNR) for ≈50 verification binary candidates. We find that 11 binaries reach a SNR≥20, two further binaries reaching a SNR≥5 and three more systems are expected to have a SNR≈5 after four years integration with LISA. For these 16 systems we present predictions of the gravitational wave amplitude (A) and parameter uncertainties from Fisher information matrix on the amplitude (A) and inclination (ι).
Gravitational microlensing - The effect of random motion of individual stars in the lensing galaxy

NASA Technical Reports Server (NTRS)

Kundic, Tomislav; Wambsganss, Joachim

1993-01-01

We investigate the influence of random motion of individual stars in the lensing galaxy on the light curve of a gravitationally lensed background quasar. We compare this with the effects of the transverse motion of the galaxy. We find that three-dimensional random motion of stars with a velocity dispersion sigma in each dimension is more effective in producing 'peaks' in a microlensed light curve by a factor a about 1.3 than motion of the galaxy with a transverse velocity v(t) = sigma. This effectiveness parameter a seems to depend only weakly on the surface mass density. With an assumed transverse velocity of v(t) = 600 km/s of the galaxy lensing the QSO 2237+0305 and a measured velocity dispersion of sigma = 215 km/s, the expected rate of maxima in the light curves calculated for bulk motion alone has to be increased by about 10 percent due to the random motion of stars. As a consequence, the average time interval Delta t between two high-magnification events is smaller than the time interval Delta(t) bulk, calculated for bulk motion alone, Delta t about 0.9 Delta(t) bulk.
Does the Galactic Bulge Have Fewer Planets?

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-12-01

The Milky Ways dense central bulge is a very different environment than the surrounding galactic disk in which we live. Do the differences affect the ability of planets to form in the bulge?Exploring Galactic PlanetsSchematic illustrating how gravitational microlensing by an extrasolar planet works. [NASA]Planet formation is a complex process with many aspects that we dont yet understand. Do environmental properties like host star metallicity, the density of nearby stars, or the intensity of the ambient radiation field affect the ability of planets to form? To answer these questions, we will ultimately need to search for planets around stars in a large variety of different environments in our galaxy.One way to detect recently formed, distant planets is by gravitational microlensing. In this process, light from a distant source star is bent by a lens star that is briefly located between us and the source. As the Earth moves, this momentary alignment causes a blip in the sources light curve that we can detect and planets hosted by the lens star can cause an additional observable bump.Artists impression of the Milky Way galaxy. The central bulge is much denserthan the surroundingdisk. [ESO/NASA/JPL-Caltech/M. Kornmesser/R. Hurt]Relative AbundancesMost source stars reside in the galactic bulge, so microlensing events can probe planetary systems at any distance between the Earth and the galactic bulge. This means that planet detections from microlensing could potentially be used to measure the relative abundances of exoplanets in different parts of our galaxy.A team of scientists led by Matthew Penny, a Sagan postdoctoral fellow at Ohio State University, set out to do just that. The group considered a sample of 31 exoplanetary systems detected by microlensing and asked the following question: are the planet abundances in the galactic bulge and the galactic disk the same?A Paucity of PlanetsTo answer this question, Penny and collaborators derived the expected distribution of host distances from a simulated microlensing survey, correcting for dominant selection effects. They then compared the distribution of distances in this model sample to the distribution of distances measured for the actual, observed systems.Histogram and cumulative distribution (black lines) of distance estimates for microlensing planet hosts. Red lines show the distributions predicted by the model if the disk and bulge abundances were the same. [Penny et al. 2016]Intriguingly, the two distributions dont match when you assume that the planet abundances in the disk and the bulge are the same. The relative abundances appear to be higher in the disk than in the bulge, according to the teams results: the observations agree with a model in which the bulge/disk abundance ratio is less than 0.54.Whats to Blame?There are a few ways to interpret this result: 1) distance measurements for the sample of planets discovered by microlensing have errors, 2) the model is too simplified; it needs to also include dependence of planet abundance and detection sensitivity on properties like host mass and metallicity, or 3) the galactic bulge actually has fewer planets than the disk.Penny and collaboratorssuspect some combination of the first two interpretations is most likely, but an actual paucity of planets in the galactic bulge cant be ruled out. Performing similar analysis on a larger sample of microlensing planets expected from upcoming, second-generation microlensing searches and obtaining more accurate distance measurements will help us to address this puzzlemore definitively in the future.CitationMatthew T. Penny et al 2016 ApJ 830 150. doi:10.3847/0004-637X/830/2/150
Search for gravitational waves from compact binary coalescence in LIGO and Virgo data from S5 and VSR1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abadie, J.; Abbott, B. P.; Abbott, R.

We report the results of the first search for gravitational waves from compact binary coalescence using data from the Laser Interferometer Gravitational-Wave Observatory and Virgo detectors. Five months of data were collected during the Laser Interferometer Gravitational-Wave Observatory's S5 and Virgo's VSR1 science runs. The search focused on signals from binary mergers with a total mass between 2 and 35M{sub {center_dot}}. No gravitational waves are identified. The cumulative 90%-confidence upper limits on the rate of compact binary coalescence are calculated for nonspinning binary neutron stars, black hole-neutron star systems, and binary black holes to be 8.7x10{sup -3} yr{sup -1} L{submore » 10}{sup -1}, 2.2x10{sup -3} yr{sup -1} L{sub 10}{sup -1}, and 4.4x10{sup -4} yr{sup -1} L{sub 10}{sup -1}, respectively, where L{sub 10} is 10{sup 10} times the blue solar luminosity. These upper limits are compared with astrophysical expectations.« less
Effect of eccentricity on searches for gravitational waves from coalescing compact binaries in ground-based detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Duncan A.; Zimmerman, Peter J.

2010-01-15

Inspiralling compact binaries are expected to circularize before their gravitational-wave signals reach the sensitive frequency band of ground-based detectors. Current searches for gravitational waves from compact binaries using the LIGO and Virgo detectors therefore use circular templates to construct matched filters. Binary formation models have been proposed which suggest that some systems detectable by the LIGO-Virgo network may have non-negligible eccentricity. We investigate the ability of the restricted 3.5 post-Newtonian order TaylorF2 template bank, used by LIGO and Virgo to search for gravitational waves from compact binaries with masses M{<=}35M{sub {center_dot},} to detect binaries with nonzero eccentricity. We model themore » gravitational waves from eccentric binaries using the x-model post-Newtonian formalism proposed by Hinder et al.[I. Hinder, F. Hermann, P. Laguna, and D. Shoemaker, arXiv:0806.1037v1]. We find that small residual eccentricities (e{sub 0} < or approx. 0.05 at 40 Hz) do not significantly affect the ability of current LIGO searches to detect gravitational waves from coalescing compact binaries with total mass 2M{sub {center_dot}<}M<15M{sub {center_dot}.} For eccentricities e{sub 0} > or approx. 0.1, the loss in matched filter signal-to-noise ratio due to eccentricity can be significant and so templates which include eccentric effects will be required to perform optimal searches for such systems.« less
SPITZER MICROLENS MEASUREMENT OF A MASSIVE REMNANT IN A WELL-SEPARATED BINARY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shvartzvald, Y.; Bryden, G.; Henderson, C. B.

2015-12-01

We report the detection and mass measurement of a binary lens OGLE-2015-BLG-1285La,b, with the more massive component having M{sub 1} > 1.35 M{sub ⊙} (80% probability). A main-sequence star in this mass range is ruled out by limits on blue light, meaning that a primary in this mass range must be a neutron star (NS) or black hole (BH). The system has a projected separation r{sub ⊥} = 6.1 ± 0.4 AU and lies in the Galactic bulge. These measurements are based on the “microlens parallax” effect, i.e., comparing the microlensing light curve as seen from Spitzer, which lay atmore » 1.25 AU projected from Earth, to the light curves from four ground-based surveys, three in the optical and one in the near-infrared. Future adaptive optics imaging of the companion by 30 m class telescopes will yield a much more accurate measurement of the primary mass. This discovery both opens the path and defines the challenges to detecting and characterizing BHs and NSs in wide binaries, with either dark or luminous companions. In particular, we discuss lessons that can be applied to future Spitzer and Kepler K2 microlensing parallax observations.« less
Detection of Gravitational Wave Emission by Supermassive Black Hole Binaries Through Tidal Disruption Flares.

PubMed

Hayasaki, Kimitake; Loeb, Abraham

2016-10-21

Galaxy mergers produce supermassive black hole binaries, which emit gravitational waves prior to their coalescence. We perform three-dimensional hydrodynamic simulations to study the tidal disruption of stars by such a binary in the final centuries of its life. We find that the gas stream of the stellar debris moves chaotically in the binary potential and forms accretion disks around both black holes. The accretion light curve is modulated over the binary orbital period owing to relativistic beaming. This periodic signal allows to detect the decay of the binary orbit due to gravitational wave emission by observing two tidal disruption events that are separated by more than a decade.
Detection of Gravitational Wave Emission by Supermassive Black Hole Binaries Through Tidal Disruption Flares

PubMed Central

Hayasaki, Kimitake; Loeb, Abraham

2016-01-01

Galaxy mergers produce supermassive black hole binaries, which emit gravitational waves prior to their coalescence. We perform three-dimensional hydrodynamic simulations to study the tidal disruption of stars by such a binary in the final centuries of its life. We find that the gas stream of the stellar debris moves chaotically in the binary potential and forms accretion disks around both black holes. The accretion light curve is modulated over the binary orbital period owing to relativistic beaming. This periodic signal allows to detect the decay of the binary orbit due to gravitational wave emission by observing two tidal disruption events that are separated by more than a decade. PMID:27767188
Microlensing for extrasolar planets : improving the photometry

NASA Astrophysics Data System (ADS)

Bajek, David J.

2013-08-01

Gravitational Microlensing, as a technique for detecting Extrasolar Planets, is recognised for its potential in discovering small-mass planets similar to Earth, at a distance of a few Astronomical Units from their host stars. However, analysing the data from microlensing events (which statistically rarely reveal planets) is complex and requires continued and intensive use of various networks of telescopes working together in order to observe the phenomenon. As such the techniques are constantly being developed and refined; this project outlines some steps of the careful analysis required to model an event and ensure the best quality data is used in the fitting. A quantitative investigation into increasing the quality of the original photometric data available from any microlensing event demonstrates that 'lucky imaging' can lead to a marked improvement in the signal to noise ratio of images over standard imaging techniques, which could result in more accurate models and thus the calculation of more accurate planetary parameters. In addition, a simulation illustrating the effects of atmospheric turbulence on exposures was created, and expanded upon to give an approximation of the lucky imaging technique. This further demonstrated the advantages of lucky images which are shown to potentially approach the quality of those expected from diffraction limited photometry. The simulation may be further developed for potential future use as a 'theoretical lucky imager' in our research group, capable of producing and analysing synthetic exposures through customisable conditions.
Empirical constraints on alternative gravity theories from gravitational lensing

NASA Astrophysics Data System (ADS)

Mortlock, Daniel J.; Turner, Edwin L.

2001-10-01

If it is hypothesized that there is no dark matter, then some alternative gravitational theory must take the place of general relativity (GR) on the largest scales. Dynamical measurements can be used to investigate the nature of such a theory, but only where there is visible matter. Gravitational lensing is potentially a more powerful probe as it can be used to measure deflections far from the lens and, for sufficiently large separations, allow it to be treated as a point-mass. Microlensing within the local group does not yet provide any interesting constraints, as only images formed close to the deflectors are appreciably magnified, but stacking of multiple light-curves and observations of microlensing on cosmological scales may be able to discriminate between GR and non-dark matter theories. Galaxy-galaxy lensing is likely to be a more powerful probe of gravity, with the Sloan Digital Sky Survey (SDSS) commissioning data used here to constrain the deflection law of galaxies to be A(R)~R0.1+/-0.1 for impact parameters in the range 50kpc<~R<~1Mpc. Together with observations of flat rotation curves, these results imply that, in any gravitational theory, photons must experience (close to) twice the deflection of massive particles moving at the speed of light (at least on these physical scales). The full SDSS data set will also be sensitive to asymmetry in the lensing signal and to variation of the deflection law with galaxy type. A detection of either of these effects would represent an independent confirmation that galaxies are dark matter-dominated; conversely, azimuthal symmetry of the shear signal would rule out the typically ellipsoidal haloes predicted by most simulations of structure formation.
Error analysis of numerical gravitational waveforms from coalescing binary black holes

NASA Astrophysics Data System (ADS)

Fong, Heather; Chu, Tony; Kumar, Prayush; Pfeiffer, Harald; Boyle, Michael; Hemberger, Daniel; Kidder, Lawrence; Scheel, Mark; Szilagyi, Bela; SXS Collaboration

2016-03-01

The Advanced Laser Interferometer Gravitational-wave Observatory (Advanced LIGO) has finished a successful first observation run and will commence its second run this summer. Detection of compact object binaries utilizes matched-filtering, which requires a vast collection of highly accurate gravitational waveforms. This talk will present a set of about 100 new aligned-spin binary black hole simulations. I will discuss their properties, including a detailed error analysis, which demonstrates that the numerical waveforms are sufficiently accurate for gravitational wave detection purposes, as well as for parameter estimation purposes.
How gravitational lensing helps γ-ray photons avoid γ – γ absorption

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barnacka, Anna; Böttcher, Markus; Sushch, Iurii, E-mail: abarnacka@cfa.harvard.edu, E-mail: Markus.Bottcher@nwu.ac.za

2014-08-01

We investigate potential γ – γ absorption of γ-ray emission from blazars arising from inhomogeneities along the line of sight, beyond the diffuse Extragalactic Background Light (EBL). As plausible sources of excess γ – γ opacity, we consider (1) foreground galaxies, including cases in which this configuration leads to strong gravitational lensing, (2) individual stars within these foreground galaxies, and (3) individual stars within our own galaxy, which may act as lenses for microlensing events. We found that intervening galaxies close to the line of sight are unlikely to lead to significant excess γ – γ absorption. This opens upmore » the prospect of detecting lensed gamma-ray blazars at energies above 10 GeV with their gamma-ray spectra effectively only affected by the EBL. The most luminous stars located either in intervening galaxies or in our galaxy provide an environment in which these gamma-rays could, in principle, be significantly absorbed. However, despite a large microlensing probability due to stars located in intervening galaxies, γ-rays avoid absorption by being deflected by the gravitational potentials of such intervening stars to projected distances ({sup i}mpact parameters{sup )} where the resulting γ – γ opacities are negligible. Thus, neither of the intervening excess photon fields considered here, provide a substantial source of excess γ – γ opacity beyond the EBL, even in the case of very close alignments between the background blazar and a foreground star or galaxy.« less
Testing General Relativity with Low-Frequency, Space-Based Gravitational-Wave Detectors.

PubMed

Gair, Jonathan R; Vallisneri, Michele; Larson, Shane L; Baker, John G

2013-01-01

We review the tests of general relativity that will become possible with space-based gravitational-wave detectors operating in the ∼ 10 -5 - 1 Hz low-frequency band. The fundamental aspects of gravitation that can be tested include the presence of additional gravitational fields other than the metric; the number and tensorial nature of gravitational-wave polarization states; the velocity of propagation of gravitational waves; the binding energy and gravitational-wave radiation of binaries, and therefore the time evolution of binary inspirals; the strength and shape of the waves emitted from binary mergers and ringdowns; the true nature of astrophysical black holes; and much more. The strength of this science alone calls for the swift implementation of a space-based detector; the remarkable richness of astrophysics, astronomy, and cosmology in the low-frequency gravitational-wave band make the case even stronger.
VizieR Online Data Catalog: OGLE eclipsing binaries in LMC (Wyrzykowski+, 2003)

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Udalski, A.; Kubiak, M.; Szymanski, M.; Zebrun, K.; Soszynski, I.; Wozniak, P. R.; Pietrzynski, G.; Szewczyk, O.

2003-09-01

We present the catalog of 2580 eclipsing binary stars detected in 4.6 square degree area of the central parts of the Large Magellanic Cloud. The photometric data were collected during the second phase of the OGLE microlensing search from 1997 to 2000. The eclipsing objects were selected with the automatic search algorithm based on an artificial neural network. Basic statistics of eclipsing stars are presented. Also, the list of 36 candidates of detached eclipsing binaries for spectroscopic study and for precise LMC distance determination is provided. The full catalog is accessible from the OGLE Internet archive. (2 data files).
Search for gravitational waves from binary black hole inspiral, merger, and ringdown

NASA Astrophysics Data System (ADS)

Abadie, J.; Abbott, B. P.; Abbott, R.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Ajith, P.; Allen, B.; Allen, G. S.; Amador Ceron, E.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Antonucci, F.; Arain, M. A.; Araya, M. C.; Aronsson, M.; Aso, Y.; Aston, S. M.; Astone, P.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Babak, S.; Baker, P.; Ballardin, G.; Ballinger, T.; Ballmer, S.; Barker, D.; Barnum, S.; Barone, F.; Barr, B.; Barriga, P.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Bauchrowitz, J.; Bauer, Th. S.; Behnke, B.; Beker, M. G.; Belletoile, A.; Benacquista, M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birindelli, S.; Biswas, R.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Blom, M.; Boccara, C.; Bock, O.; Bodiya, T. P.; Bondarescu, R.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, S.; Bosi, L.; Bouhou, B.; Boyle, M.; Braccini, S.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Breyer, J.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Budzyński, R.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burguet-Castell, J.; Burmeister, O.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cain, J.; Calloni, E.; Camp, J. B.; Campagna, E.; Campsie, P.; Cannizzo, J.; Cannon, K.; Canuel, B.; Cao, J.; Capano, C.; Carbognani, F.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chaibi, O.; Chalermsongsak, T.; Chalkley, E.; Charlton, P.; Chassande-Mottin, E.; Chelkowski, S.; Chen, Y.; Chincarini, A.; Christensen, N.; Chua, S. S. Y.; Chung, C. T. Y.; Clark, D.; Clark, J.; Clayton, J. H.; Cleva, F.; Coccia, E.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, R.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coulon, J.-P.; Coward, D. M.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Culter, R. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; D'Antonio, S.; Danzmann, K.; Das, K.; Dattilo, V.; Daudert, B.; Davier, M.; Davies, G.; Davis, A.; Daw, E. J.; Day, R.; Dayanga, T.; Derosa, R.; Debra, D.; Debreczeni, G.; Degallaix, J.; Del Prete, M.; Dergachev, V.; de Rosa, R.; Desalvo, R.; Devanka, P.; Dhurandhar, S.; di Fiore, L.; di Lieto, A.; di Palma, I.; di Paolo Emilio, M.; di Virgilio, A.; Díaz, M.; Dietz, A.; Donovan, F.; Dooley, K. L.; Doomes, E. E.; Dorsher, S.; Douglas, E. S. D.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Dueck, J.; Dumas, J.-C.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Ely, G.; Engel, R.; Etzel, T.; Evans, M.; Evans, T.; Fafone, V.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Ferrante, I.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Flaminio, R.; Flanigan, M.; Flasch, K.; Foley, S.; Forrest, C.; Forsi, E.; Forte, L. A.; Fotopoulos, N.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Galimberti, M.; Gammaitoni, L.; Garofoli, J. A.; Garufi, F.; Gáspár, M. E.; Gemme, G.; Genin, E.; Gennai, A.; Gholami, I.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gill, C.; Goetz, E.; Goggin, L. M.; González, G.; Gorodetsky, M. L.; Goßler, S.; Gouaty, R.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Greverie, C.; Grosso, R.; Grote, H.; Grunewald, S.; Guidi, G. M.; Gustafson, E. K.; Gustafson, R.; Hage, B.; Hall, P.; Hallam, J. M.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Haughian, K.; Hayama, K.; Hayau, J.-F.; Hayler, T.; Heefner, J.; Heitmann, H.; Hello, P.; Heng, I. S.; Heptonstall, A. W.; Hewitson, M.; Hild, S.; Hirose, E.; Hoak, D.; Hodge, K. A.; Holt, K.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hoyland, D.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Jaranowski, P.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kanner, J. B.; Katsavounidis, E.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kells, W.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, H.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kondrashov, V.; Kopparapu, R.; Koranda, S.; Kowalska, I.; Kozak, D.; Krause, T.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Królak, A.; Kuehn, G.; Kullman, J.; Kumar, R.; Kwee, P.; Landry, M.; Lang, M.; Lantz, B.; Lastzka, N.; Lazzarini, A.; Leaci, P.; Leong, J.; Leonor, I.; Leroy, N.; Letendre, N.; Li, J.; Li, T. G. F.; Liguori, N.; Lin, H.; Lindquist, P. E.; Lockerbie, N. A.; Lodhia, D.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lu, P.; Luan, J.; Lubiński, M.; Lucianetti, A.; Lück, H.; Lundgren, A. D.; Machenschalk, B.; Macinnis, M.; Mageswaran, M.; Mailand, K.; Majorana, E.; Mak, C.; Maksimovic, I.; Man, N.; Mandel, I.; Mandic, V.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Masserot, A.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIvor, G.; McKechan, D. J. A.; Meadors, G.; Mehmet, M.; Meier, T.; Melatos, A.; Melissinos, A. C.; Mendell, G.; Menéndez, D. F.; Mercer, R. A.; Merill, L.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Michel, C.; Milano, L.; Miller, J.; Minenkov, Y.; Mino, Y.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Mohan, M.; Mohanty, S. D.; Mohapatra, S. R. P.; Moraru, D.; Moreau, J.; Moreno, G.; Morgado, N.; Morgia, A.; Morioka, T.; Mors, K.; Mosca, S.; Moscatelli, V.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Müller-Ebhardt, H.; Munch, J.; Murray, P. G.; Nash, T.; Nawrodt, R.; Nelson, J.; Neri, I.; Newton, G.; Nishizawa, A.; Nocera, F.; Nolting, D.; Ochsner, E.; O'Dell, J.; Ogin, G. H.; Oldenburg, R. G.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Page, A.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Pardi, S.; Pareja, M.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patel, P.; Pathak, D.; Pedraza, M.; Pekowsky, L.; Penn, S.; Peralta, C.; Perreca, A.; Persichetti, G.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Plissi, M. V.; Poggiani, R.; Postiglione, F.; Prato, M.; Predoi, V.; Price, L. R.; Prijatelj, M.; Principe, M.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Quetschke, V.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radke, T.; Radkins, H.; Raffai, P.; Rakhmanov, M.; Rankins, B.; Rapagnani, P.; Raymond, V.; Re, V.; Reed, C. M.; Reed, T.; Regimbau, T.; Reid, S.; Reitze, D. H.; Ricci, F.; Riesen, R.; Riles, K.; Roberts, P.; Robertson, N. A.; Robinet, F.; Robinson, C.; Robinson, E. L.; Rocchi, A.; Roddy, S.; Rolland, L.; Rollins, J.; Romano, J. D.; Romano, R.; Romie, J. H.; Rosińska, D.; Röver, C.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sakata, S.; Sakosky, M.; Salemi, F.; Sammut, L.; Sancho de La Jordana, L.; Sandberg, V.; Sannibale, V.; Santamaría, L.; Santostasi, G.; Saraf, S.; Sassolas, B.; Sathyaprakash, B. S.; Sato, S.; Satterthwaite, M.; Saulson, P. R.; Savage, R.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Searle, A. C.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sergeev, A.; Shaddock, D. A.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sibley, A.; Siemens, X.; Sigg, D.; Singer, A.; Sintes, A. M.; Skelton, G.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, N. D.; Somiya, K.; Sorazu, B.; Speirits, F. C.; Sperandio, L.; Stein, A. J.; Stein, L. C.; Steinlechner, S.; Steplewski, S.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S.; Stroeer, A. S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sung, M.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Szokoly, G. P.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, J. R.; Taylor, R.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Thüring, A.; Titsler, C.; Tokmakov, K. V.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C.; Torrie, C. I.; Tournefier, E.; Travasso, F.; Traylor, G.; Trias, M.; Tseng, K.; Turner, L.; Ugolini, D.; Urbanek, K.; Vahlbruch, H.; Vaishnav, B.; Vajente, G.; Vallisneri, M.; van den Brand, J. F. J.; van den Broeck, C.; van der Putten, S.; van der Sluys, M. V.; van Veggel, A. A.; Vass, S.; Vasuth, M.; Vaulin, R.; Vavoulidis, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Veltkamp, C.; Verkindt, D.; Vetrano, F.; Viceré, A.; Villar, A. E.; Vinet, J.-Y.; Vocca, H.; Vorvick, C.; Vyachanin, S. P.; Waldman, S. J.; Wallace, L.; Wanner, A.; Ward, R. L.; Was, M.; Wei, P.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wen, S.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D.; Whiting, B. F.; Wilkinson, C.; Willems, P. A.; Williams, L.; Willke, B.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Woan, G.; Wooley, R.; Worden, J.; Yakushin, I.; Yamamoto, H.; Yamamoto, K.; Yeaton-Massey, D.; Yoshida, S.; Yu, P.; Yvert, M.; Zanolin, M.; Zhang, L.; Zhang, Z.; Zhao, C.; Zotov, N.; Zucker, M. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2011-06-01

We present the first modeled search for gravitational waves using the complete binary black-hole gravitational waveform from inspiral through the merger and ringdown for binaries with negligible component spin. We searched approximately 2 years of LIGO data, taken between November 2005 and September 2007, for systems with component masses of 1-99M⊙ and total masses of 25-100M⊙. We did not detect any plausible gravitational-wave signals but we do place upper limits on the merger rate of binary black holes as a function of the component masses in this range. We constrain the rate of mergers for 19M⊙≤m1, m2≤28M⊙ binary black-hole systems with negligible spin to be no more than 2.0Mpc-3Myr-1 at 90% confidence.

Gaia16aye is a binary microlensing event and is crossing the caustic again

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Leto, G.; Altavilla, G.; Bakis, V.; Britavskiy, N.; Burgaz, U.; Butterley, T.; Carrasco, J. M.; Dhillon, V. S.; Dominik, M.; Gomboc, A.; Hardy, L. K.; Littlefair, S. P.; Maund, J. R.; Piascik, A.; Rhodes, L.; Sanchez, R. Z.; Sokolovsky, K. V.; Steele, I.; Wilson, R. W.; Hamanowicz, A.; Mroz, P.; Pawlak, M.; Rybicki, K.; Sitek, M.; Mikolajczyk, P.; Kolaczkowski, Z.; Street, R.; Bendjoya, P.; Bozza, V.; Dziedzic, J.; Niczyj, K.; Nowicki, R.; Porebski, M.

2016-09-01

Galactic Plane (Cygnus) transient, Gaia16aye, nicknamed Ayers Rock (19:40:01.13 +30:07:53.4, J2000), was discovered by Gaia Science Alerts, http://gsaweb.ast.cam.ac.uk/alerts/alert/Gaia16aye, on 2016-08-05 as a flare on an otherwise quiet star.
Initial light curve of Q2237 + 0305

NASA Technical Reports Server (NTRS)

Corrigan, R. T.; Irwin, M. J.; Arnaud, J.; Fahlman, G. G.; Fletcher, J. M.

1991-01-01

This paper presents CCD photometry for the gravitationally lensed quasar system 2237 + 0305, in optical passbands from B through R, taken over a time period of more than 3 yr. These data provide new information about the probable microlensing event reported by Irwin et al. (1989); the rise time of this feature is approximately 26 days. Four additional independent brightness changes in the quasar images are detected.
Prospects for Observing Ultracompact Binaries with Space-Based Gravitational Wave Interferometers and Optical Telescopes

NASA Technical Reports Server (NTRS)

Littenberg, T. B.; Larson, S. L.; Nelemans, G.; Cornish, N. J.

2012-01-01

Space-based gravitational wave interferometers are sensitive to the galactic population of ultracompact binaries. An important subset of the ultracompact binary population are those stars that can be individually resolved by both gravitational wave interferometers and electromagnetic telescopes. The aim of this paper is to quantify the multimessenger potential of space-based interferometers with arm-lengths between 1 and 5 Gm. The Fisher information matrix is used to estimate the number of binaries from a model of the Milky Way which are localized on the sky by the gravitational wave detector to within 1 and 10 deg(exp 2) and bright enough to be detected by a magnitude-limited survey.We find, depending on the choice ofGW detector characteristics, limiting magnitude and observing strategy, that up to several hundred gravitational wave sources could be detected in electromagnetic follow-up observations.
On the use of higher order wave forms in the search for gravitational waves emitted by compact binary coalescences

NASA Astrophysics Data System (ADS)

McKechan, David J. A.

2010-11-01

This thesis concerns the use, in gravitational wave data analysis, of higher order wave form models of the gravitational radiation emitted by compact binary coalescences. We begin with an introductory chapter that includes an overview of the theory of general relativity, gravitational radiation and ground-based interferometric gravitational wave detectors. We then discuss, in Chapter 2, the gravitational waves emitted by compact binary coalescences, with an explanation of higher order waveforms and how they differ from leading order waveforms we also introduce the post-Newtonian formalism. In Chapter 3 the method and results of a gravitational wave search for low mass compact binary coalescences using a subset of LIGO's 5th science run data are presented and in the subsequent chapter we examine how one could use higher order waveforms in such analyses. We follow the development of a new search algorithm that incorporates higher order waveforms with promising results for detection efficiency and parameter estimation. In Chapter 5, a new method of windowing time-domain waveforms that offers benefit to gravitational wave searches is presented. The final chapter covers the development of a game designed as an outreach project to raise public awareness and understanding of the search for gravitational waves.
Search for Gravitational Waves from Compact Binary Coalescence in LIGO and Virgo Data from S5 and VSR1

NASA Technical Reports Server (NTRS)

Abadie, J.; Abbott, B. P.; Abbott, R.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Ajith, P.; Allen, B.; Allen, G.;

2010-01-01

We report the results of the first search for gravitational waves from compact binary coalescence using data from the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo detectors. Five months of data were collected during the concurrent S5 (UGO) and VSRI (Virgo) science runs. The search focused on signals from binary mergers with a total mass between 2 and 35 Solar Mass. No gravitational waves are identified. The cumulative 90%-confidence upper limits on the rate of compact binary coalescence are calculated for non-spinning binary neutron stars, black hole-neutron star systems, and binary black holes to be 8.7 x 10(exp -3) / yr-1/L(sub 10) 2.2 x 10-3 yr-1L101, and 4.4 x 10(exp -4)3) / yr-1/L(sub 10) respectively, where L (sub 10) is 10(exp 10) times the blue solar luminosity. These upper limits are compared with astrophysical expectations.

RoboTAP: Target priorities for robotic microlensing observations

NASA Astrophysics Data System (ADS)

Hundertmark, M.; Street, R. A.; Tsapras, Y.; Bachelet, E.; Dominik, M.; Horne, K.; Bozza, V.; Bramich, D. M.; Cassan, A.; D'Ago, G.; Figuera Jaimes, R.; Kains, N.; Ranc, C.; Schmidt, R. W.; Snodgrass, C.; Wambsganss, J.; Steele, I. A.; Mao, S.; Ment, K.; Menzies, J.; Li, Z.; Cross, S.; Maoz, D.; Shvartzvald, Y.

2018-01-01

Context. The ability to automatically select scientifically-important transient events from an alert stream of many such events, and to conduct follow-up observations in response, will become increasingly important in astronomy. With wide-angle time domain surveys pushing to fainter limiting magnitudes, the capability to follow-up on transient alerts far exceeds our follow-up telescope resources, and effective target prioritization becomes essential. The RoboNet-II microlensing program is a pathfinder project, which has developed an automated target selection process (RoboTAP) for gravitational microlensing events, which are observed in real time using the Las Cumbres Observatory telescope network. Aims: Follow-up telescopes typically have a much smaller field of view compared to surveys, therefore the most promising microlensing events must be automatically selected at any given time from an annual sample exceeding 2000 events. The main challenge is to select between events with a high planet detection sensitivity, with the aim of detecting many planets and characterizing planetary anomalies. Methods: Our target selection algorithm is a hybrid system based on estimates of the planet detection zones around a microlens. It follows automatic anomaly alerts and respects the expected survey coverage of specific events. Results: We introduce the RoboTAP algorithm, whose purpose is to select and prioritize microlensing events with high sensitivity to planetary companions. In this work, we determine the planet sensitivity of the RoboNet follow-up program and provide a working example of how a broker can be designed for a real-life transient science program conducting follow-up observations in response to alerts; we explore the issues that will confront similar programs being developed for the Large Synoptic Survey Telescope (LSST) and other time domain surveys.
Polarimetry Microlensing of Close-in Planetary Systems

NASA Astrophysics Data System (ADS)

Sajadian, Sedighe; Hundertmark, Markus

2017-04-01

A close-in giant planetary (CGP) system has a net polarization signal whose value varies depending on the orbital phase of the planet. This polarization signal is either caused by the stellar occultation or by reflected starlight from the surface of the orbiting planet. When the CGP system is located in the Galactic bulge, its polarization signal becomes too weak to be measured directly. One method for detecting and characterizing these weak polarization signatures due to distant CGP systems is gravitational microlensing. In this work, we focus on potential polarimetric observations of highly magnified microlensing events of CGP systems. When the lens is passing directly in front of the source star with its planetary companion, the polarimetric signature caused by the transiting planet is magnified. As a result, some distinct features in the polarimetry and light curves are produced. In the same way, microlensing amplifies the reflection-induced polarization signal. While the planet-induced perturbations are magnified whenever these polarimetric or photometric deviations vanish for a moment, the corresponding magnification factor of the polarization component(s) is related to the planet itself. Finding these exact times in the planet-induced perturbations helps us to characterize the planet. In order to evaluate the observability of such systems through polarimetric or photometric observations of high-magnification microlensing events, we simulate these events by considering confirmed CGP systems as their source stars and conclude that the efficiency for detecting the planet-induced signal with the state-of-the-art polarimetric instrument (FORS2/VLT) is less than 0.1%. Consequently, these planet-induced polarimetry perturbations can likely be detected under favorable conditions by the high-resolution and short-cadence polarimeters of the next generation.
LIGO GW150914 and GW151226 gravitational wave detection and generalized gravitation theory (MOG)

NASA Astrophysics Data System (ADS)

Moffat, J. W.

2016-12-01

The nature of gravitational waves in a generalized gravitation theory is investigated. The linearized field equations and the metric tensor quadrupole moment power and the decrease in radius of an inspiralling binary system of two compact objects are derived. The generalized Kerr metric describing a spinning black hole is determined by its mass M and the spin parameter a = cS / GM2. The LIGO-Virgo collaboration data is fitted with smaller binary black hole masses in agreement with the current electromagnetic, observed X-ray binary upper bound for a black hole mass, M ≲ 10M⊙.
On the gravitational wave background from black hole binaries after the first LIGO detections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cholis, Ilias, E-mail: icholis1@jhu.edu

The detection of gravitational waves from the merger of binary black holes by the LIGO Collaboration has opened a new window to astrophysics. With the sensitivities of ground based detectors in the coming years, we will principally detect local binary black hole mergers. The integrated merger rate can instead be probed by the gravitational-wave background, the incoherent superposition of the released energy in gravitational waves during binary-black-hole coalescence. Through that, the properties of the binary black holes can be studied. In this work we show that by measuring the energy density Ω{sub GW} (in units of the cosmic critical density)more » of the gravitational-wave background, we can search for the rare ∼ 100 M {sub ⊙} massive black holes formed in the Universe. In addition, we can answer how often the least massive BHs of mass ≳ 3 M {sub ⊙} form. Finally, if there are multiple channels for the formation of binary black holes and if any of them predicts a narrow mass range for the black holes, then the total Ω{sub GW} spectrum may have features that with the future Einstein Telescope can be detected.« less
Finding A Planet Through the Dust

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2018-05-01

Finding planets in the crowded galactic center is a difficult task, but infrared microlensing surveys give us a fighting chance! Preliminary results from such a study have already revealed a new exoplanet lurking in the dust of the galactic bulge.Detection BiasesUKIRT-2017 microlensing survey fields (blue), plotted over a map showing the galactic-plane dust extinction. The location of the newly discovered giant planet is marked with blue crosshairs. [Shvartzvald et al. 2018]Most exoplanets weve uncovered thus far were found either via transits dips in a stars light as the planet passes in front of its host star or via radial velocity wobbles of the star as the orbiting planet tugs on it. These techniques, while highly effective, introduce a selection bias in the types of exoplanets we detect: both methods tend to favor discovery of close-in, large planets orbiting small stars; these systems produce the most easily measurable signals on short timescales.For this reason, microlensing surveys for exoplanets have something new to add to the field.Search for a LensIn gravitational microlensing, we observe a background star as it is briefly magnified by a passing foreground star acting as a lens. If that foreground star hosts a planet, we observe a characteristic shape in the observed brightening of the background star, and the properties of that shape can reveal information about the foreground planet.A diagram of how planets are detected via gravitational microlensing. The detectable planet is in orbit around the foreground lens star. [NASA]This technique for planet detection is unique in its ability to explore untapped regions of exoplanet parameter space with microlensing, we can survey for planets around all different types of stars (rather than primarily small, dim ones), planets of all masses near the further-out snowlines where gas and ice giants are likely to form, and even free-floating planets.In a new study led by a Yossi Shvartzvald, a NASA postdoctoral fellow at the Jet Propulsion Laboratory (JPL), a team of scientists now presents preliminary results from a near-infrared microlensing survey conducted with the United Kingdom Infrared Telescope (UKIRT) in Hawaii. Though the full study has not yet been published, the team reports on their first outcome: the detection of a giant planet in the galactic bulge.Giant Planet FoundThe light curve of UKIRT-2017-BLG-001. The inset shows a close-up of the anomaly in the curve, produced by the presence of the planet. [Shvartzvald et al. 2018]UKIRT-2017-BLG-001 is a giant planet detected at an angle of just 0.35 from the dusty, crowded Galactic center. It suffers from a high degree of extinction, implying that this planet could only have been detected via a near-infrared survey. The mass ratio of UKIRT-2017-BLG-001 to its host star is about 1.5 times that of Jupiter to the Sun, and its host star appears to be about 80% the mass of the Sun.The starplanet pair is roughly 20,500 light-years from us, which likely places it in the galactic bulge. Intriguingly, evidence suggests that the source star the star that the foreground starplanet lensed lies in the far galactic disk. If this is true, this would be the first source star of a microlensing event to be identified as belonging to the far disk.Artists impression of the WFIRST mission. [NASA]Looking AheadWhats next for microlensing exoplanet studies? The goal of the UKIRT near-infrared microlensing survey isnt just to discover planets its to characterize the exoplanet occurrence rates in different parts of the galaxy to inform future surveys.In particular, the UKIRT survey explored potential fields for the upcoming Wide Field Infrared Survey Telescope (WFIRST) mission, slated to launch in the mid-2020s. This powerful space telescope stands to vastly expand the reach of infrared microlensing detection, broadly surveying our galaxy for planets hiding in the dust.CitationY. Shvartzvald et al 2018 ApJL 857 L8. doi:10.3847/2041-8213/aab71b
Stochastic Gravitational-Wave Background due to Primordial Binary Black Hole Mergers.

PubMed

Mandic, Vuk; Bird, Simeon; Cholis, Ilias

2016-11-11

Recent Advanced LIGO detections of binary black hole mergers have prompted multiple studies investigating the possibility that the heavy GW150914 binary system was of primordial origin, and hence could be evidence for dark matter in the form of black holes. We compute the stochastic background arising from the incoherent superposition of such primordial binary black hole systems in the Universe and compare it to the similar background spectrum due to binary black hole systems of stellar origin. We investigate the possibility of detecting this background with future gravitational-wave detectors, and conclude that constraining the dark matter component in the form of black holes using stochastic gravitational-wave background measurements will be very challenging.
Analytic gravitational waveforms for generic precessing compact binaries

NASA Astrophysics Data System (ADS)

Chatziioannou, Katerina; Klein, Antoine; Cornish, Neil; Yunes, Nicolas

2017-01-01

Gravitational waves from compact binaries are subject to amplitude and phase modulations arising from interactions between the angular momenta of the system. Failure to account for such spin-precession effects in gravitational wave data analysis could hinder detection and completely ruin parameter estimation. In this talk I will describe the construction of closed-form, frequency-domain waveforms for fully-precessing, quasi-circular binary inspirals. The resulting waveforms can model spinning binaries of arbitrary spin magnitudes, spin orientations, and masses during the inspiral phase. I will also describe ongoing efforts to extend these inspiral waveforms to the merger and ringdown phases.
Localization of binary neutron star mergers with second and third generation gravitational-wave detectors

NASA Astrophysics Data System (ADS)

Mills, Cameron; Tiwari, Vaibhav; Fairhurst, Stephen

2018-05-01

The observation of gravitational wave signals from binary black hole and binary neutron star mergers has established the field of gravitational wave astronomy. It is expected that future networks of gravitational wave detectors will possess great potential in probing various aspects of astronomy. An important consideration for successive improvement of current detectors or establishment on new sites is knowledge of the minimum number of detectors required to perform precision astronomy. We attempt to answer this question by assessing the ability of future detector networks to detect and localize binary neutron stars mergers on the sky. Good localization ability is crucial for many of the scientific goals of gravitational wave astronomy, such as electromagnetic follow-up, measuring the properties of compact binaries throughout cosmic history, and cosmology. We find that although two detectors at improved sensitivity are sufficient to get a substantial increase in the number of observed signals, at least three detectors of comparable sensitivity are required to localize majority of the signals, typically to within around 10 deg2 —adequate for follow-up with most wide field of view optical telescopes.
Gravitational-wave localization alone can probe origin of stellar-mass black hole mergers.

PubMed

Bartos, I; Haiman, Z; Marka, Z; Metzger, B D; Stone, N C; Marka, S

2017-10-10

The recent discovery of gravitational waves from stellar-mass binary black hole mergers by the Laser Interferometer Gravitational-wave Observatory opened the door to alternative probes of stellar and galactic evolution, cosmology and fundamental physics. Probing the origin of binary black hole mergers will be difficult due to the expected lack of electromagnetic emission and limited localization accuracy. Associations with rare host galaxy types-such as active galactic nuclei-can nevertheless be identified statistically through spatial correlation. Here we establish the feasibility of statistically proving the connection between binary black hole mergers and active galactic nuclei as hosts, even if only a sub-population of mergers originate from active galactic nuclei. Our results are the demonstration that the limited localization of gravitational waves, previously written off as not useful to distinguish progenitor channels, can in fact contribute key information, broadening the range of astrophysical questions probed by binary black hole observations.Binary black hole mergers have recently been observed through the detection of gravitational wave signatures. The authors demonstrate that their association with active galactic nuclei can be made through a statistical spatial correlation.
VizieR Online Data Catalog: OGLE-III Galactic bulge microlensing events (Wyrzykowski+, 2015)

NASA Astrophysics Data System (ADS)

Wyrzykowski, L.; Rynkiewicz, A. E.; Skowron, J.; Kozlowski, S.; Udalski, A.; Szymanski, M. K.; Kubiak, M.; Soszynski, I.; Pietrzynski, G.; Poleski, R.; Pietrukowicz, P.; Pawlak, M.

2015-02-01

The data used in this work were photometry of 150 million objects toward more than 31deg2 of the Galactic bulge observed in almost 74000 frames, i.e., about 11000 billion data points. We selected 91 fields out of all 177 ever observed by the Optical Gravitational Lensing Experiment (OGLE) Udalski et al. (2008AcA....58...69U) in its third phase from 2001 July until 2009 May, which had at least 250 observations. We use the re-reduced data obtained after the end of OGLE-III. For the final sample of microlensing events, we additionally produced new photometry which took into account the exact position of each event on the difference imaging technique (DIA, Wozniak 2000, J/AcA/50/421) image (see section 2). (4 data files).
Gravitational waves from binary supermassive black holes missing in pulsar observations.

PubMed

Shannon, R M; Ravi, V; Lentati, L T; Lasky, P D; Hobbs, G; Kerr, M; Manchester, R N; Coles, W A; Levin, Y; Bailes, M; Bhat, N D R; Burke-Spolaor, S; Dai, S; Keith, M J; Osłowski, S; Reardon, D J; van Straten, W; Toomey, L; Wang, J-B; Wen, L; Wyithe, J S B; Zhu, X-J

2015-09-25

Gravitational waves are expected to be radiated by supermassive black hole binaries formed during galaxy mergers. A stochastic superposition of gravitational waves from all such binary systems would modulate the arrival times of pulses from radio pulsars. Using observations of millisecond pulsars obtained with the Parkes radio telescope, we constrained the characteristic amplitude of this background, A(c,yr), to be <1.0 × 10(-15) with 95% confidence. This limit excludes predicted ranges for A(c,yr) from current models with 91 to 99.7% probability. We conclude that binary evolution is either stalled or dramatically accelerated by galactic-center environments and that higher-cadence and shorter-wavelength observations would be more sensitive to gravitational waves. Copyright © 2015, American Association for the Advancement of Science.
Can we identify massless braneworld black holes by observations?

NASA Astrophysics Data System (ADS)

Kuniyasu, Masashi; Nanri, Keitaro; Sakai, Nobuyuki; Ohgami, Takayuki; Fukushige, Ryosuke; Komura, Subaru

2018-05-01

For an extension of the previous work on gravitational lensing by massless braneworld black holes, we investigate their microlensing phenomena and shadows and discuss how to distinguish them from standard Schwarzschild black holes and Ellis wormholes. Microlensing is known as the phenomenon in which luminosity amplification appears when a bright object passes behind a black hole or another massive object. We find that, for the braneworld black hole as well as for the Ellis wormhole, there appears luminosity reduction just before and after the amplification. This means that observation of such a reduction would indicate the lens object is either a braneworld black hole or a wormhole, though it is difficult to distinguish one from the other by microlensing solely. Therefore, we next analyze the optical images, or shadows of the braneworld black hole surrounded by optically thin dust, and compare them to those of the Ellis wormhole. Because the spacetime around the braneworld black hole possesses unstable circular orbits of photons, a bright ring appears in the image, just as in Schwarzschild spacetime or in the wormhole spacetime. This indicates that the appearance of a bright ring does not solely confirm a braneworld black hole, a Schwarzschild, nor an Ellis wormhole. However, we find that only for the wormhole is the intensity inside the ring larger than that the outsider intensity. Therefore, with future high-resolution observations of microlensing and shadows together, we could identify the braneworld black holes if they exist.
A calibration of the stellar mass fundamental plane at z ∼ 0.5 using the micro-lensing-induced flux ratio anomalies of macro-lensed quasars {sup ,} {sup ,}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schechter, Paul L.; Pooley, David; Blackburne, Jeffrey A.

2014-10-01

We measure the stellar mass surface densities of early-type galaxies by observing the micro-lensing of macro-lensed quasars caused by individual stars, including stellar remnants, brown dwarfs, and red dwarfs too faint to produce photometric or spectroscopic signatures. Instead of observing multiple micro-lensing events in a single system, we combine single-epoch X-ray snapshots of 10 quadruple systems, and compare the measured relative magnifications for the images with those computed from macro-models. We use these to normalize a stellar mass fundamental plane constructed using a Salpeter initial mass function with a low-mass cutoff of 0.1 M {sub ☉} and treat the zeropointmore » of the surface mass density as a free parameter. Our method measures the graininess of the gravitational potential produced by individual stars, in contrast to methods that decompose a smooth total gravitational potential into two smooth components, one stellar and one dark. We find the median likelihood value for the normalization factor F by which the Salpeter stellar masses must be multiplied is 1.23, with a one sigma confidence range, dominated by small number statistics, of 0.77« less
Probing gravitational parity violation with gravitational waves from stellar-mass black hole binaries

NASA Astrophysics Data System (ADS)

Yagi, Kent; Yang, Huan

2018-05-01

The recent discovery of gravitational-wave events has offered us unique test beds of gravity in the strong and dynamical field regime. One possible modification to General Relativity is the gravitational parity violation that arises naturally from quantum gravity. Such parity violation gives rise to the so-called amplitude birefringence in gravitational waves, in which one of the circularly polarized modes is amplified while the other one is suppressed during their propagation. In this paper, we study how well one can measure gravitational parity violation via the amplitude birefringence effect of gravitational waves sourced by stellar-mass black hole binaries. We choose Chern-Simons gravity as an example and work within an effective field theory formalism to ensure that the approximate theory is well posed. We consider gravitational waves from both individual sources and stochastic gravitational-wave backgrounds. Regarding bounds from individual sources, we estimate such bounds using a Fisher analysis and carry out Monte Carlo simulations by randomly distributing sources over their sky location and binary orientation. We find that the bounds on the scalar field evolution in Chern-Simons gravity from the recently discovered gravitational-wave events are too weak to satisfy the weak Chern-Simons approximation, while aLIGO with its design sensitivity can place meaningful bounds. Regarding bounds from stochastic gravitational-wave backgrounds, we set the threshold signal-to-noise ratio for detection of the parity-violation mode as 5 and estimate projected bounds with future detectors assuming that signals are consistent with no parity violation. In an ideal situation in which all the source parameters and binary black hole merger-rate history are known a priori, we find that a network of two third-generation detectors is able to place bounds that are comparable to or slightly stronger than binary pulsar bounds. In a more realistic situation in which one does not have such information beforehand, approximate bounds can be derived if the regular parity-insensitive mode is detected and the peak redshift of the merger-rate history is known theoretically. Since gravitational-wave observations probe either the difference in parity violation between the source and the detector (with individual sources) or the line-of-sight cosmological integration of the scalar field (with gravitational-wave backgrounds), such bounds are complementary to local measurements from solar system experiments and binary pulsar observations.
Waveform model for an eccentric binary black hole based on the effective-one-body-numerical-relativity formalism

NASA Astrophysics Data System (ADS)

Cao, Zhoujian; Han, Wen-Biao

2017-08-01

Binary black hole systems are among the most important sources for gravitational wave detection. They are also good objects for theoretical research for general relativity. A gravitational waveform template is important to data analysis. An effective-one-body-numerical-relativity (EOBNR) model has played an essential role in the LIGO data analysis. For future space-based gravitational wave detection, many binary systems will admit a somewhat orbit eccentricity. At the same time, the eccentric binary is also an interesting topic for theoretical study in general relativity. In this paper, we construct the first eccentric binary waveform model based on an effective-one-body-numerical-relativity framework. Our basic assumption in the model construction is that the involved eccentricity is small. We have compared our eccentric EOBNR model to the circular one used in the LIGO data analysis. We have also tested our eccentric EOBNR model against another recently proposed eccentric binary waveform model; against numerical relativity simulation results; and against perturbation approximation results for extreme mass ratio binary systems. Compared to numerical relativity simulations with an eccentricity as large as about 0.2, the overlap factor for our eccentric EOBNR model is better than 0.98 for all tested cases, including spinless binary and spinning binary, equal mass binary, and unequal mass binary. Hopefully, our eccentric model can be the starting point to develop a faithful template for future space-based gravitational wave detectors.

VIGOR: Virtual Interaction with Gravitational Waves to Observe Relativity

NASA Astrophysics Data System (ADS)

Kitagawa, Midori; Kesden, Michael; Tranm, Ngoc; Venlayudam, Thulasi Sivampillai; Urquhart, Mary; Malina, Roger

2017-05-01

In 2015, a century after Albert Einstein published his theory of general relativity, the Laser Interferometer Gravitational-wave Observatory (LIGO) detected gravitational waves from binary black holes fully consistent with this theory. Our goal for VIGOR (Virtual-reality Interaction with Gravitational waves to Observe Relativity) is to communicate this revolutionary discovery to the public by visualizing the gravitational waves emitted by binary black holes. VIGOR has been developed using the Unity game engine and VR headsets (Oculus Rift DK2 and Samsung Gear VR). Wearing a VR headset, VIGOR users control an avatar to "fly" around binary black holes, experiment on the black holes by manipulating their total mass, mass ratio, and orbital separation, and witness how gravitational waves emitted by the black holes stretch and squeeze the avatar. We evaluated our prototype of VIGOR with high school students in 2016 and are further improving VIGOR based on our findings.
A massive binary black-hole system in OJ 287 and a test of general relativity.

PubMed

Valtonen, M J; Lehto, H J; Nilsson, K; Heidt, J; Takalo, L O; Sillanpää, A; Villforth, C; Kidger, M; Poyner, G; Pursimo, T; Zola, S; Wu, J-H; Zhou, X; Sadakane, K; Drozdz, M; Koziel, D; Marchev, D; Ogloza, W; Porowski, C; Siwak, M; Stachowski, G; Winiarski, M; Hentunen, V-P; Nissinen, M; Liakos, A; Dogru, S

2008-04-17

Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ 287. This quasar shows quasi-periodic optical outbursts at 12-year intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened 20 days later.
A Galactic Binary Detection Pipeline

NASA Technical Reports Server (NTRS)

Littenberg, Tyson B.

2011-01-01

The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers, etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract 2:: 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.
On the unreasonable effectiveness of the post-Newtonian approximation in gravitational physics

PubMed Central

Will, Clifford M.

2011-01-01

The post-Newtonian approximation is a method for solving Einstein’s field equations for physical systems in which motions are slow compared to the speed of light and where gravitational fields are weak. Yet it has proven to be remarkably effective in describing certain strong-field, fast-motion systems, including binary pulsars containing dense neutron stars and binary black hole systems inspiraling toward a final merger. The reasons for this effectiveness are largely unknown. When carried to high orders in the post-Newtonian sequence, predictions for the gravitational-wave signal from inspiraling compact binaries will play a key role in gravitational-wave detection by laser-interferometric observatories. PMID:21447714
Gravitational wave probes of parity violation in compact binary coalescences

NASA Astrophysics Data System (ADS)

Alexander, Stephon H.; Yunes, Nicolás

2018-03-01

Is gravity parity violating? Given the recent observations of gravitational waves from coalescing compact binaries, we develop a strategy to find an answer with current and future detectors. We identify the key signatures of parity violation in gravitational waves: amplitude birefringence in their propagation and a modified chirping rate in their generation. We then determine the optimal binaries to test the existence of parity violation in gravity, and prioritize the research in modeling that will be required to carry out such tests before detectors reach their design sensitivity.
Map of Exoplanets Found in Our Galaxy Artist Concept

NASA Image and Video Library

2015-04-14

Astronomers have discovered one of the most distant planets known, a gas giant about 13,000 light-years from Earth, called OGLE-2014-BLG-0124L. The planet was discovered using a technique called microlensing, and the help of NASA's Spitzer Space Telescope and the Optical Gravitational Lensing Experiment, or OGLE. In this artist's illustration, planets discovered with microlensing are shown in yellow. The farthest lies in the center of our galaxy, 25,000 light-years away. Most of the known exoplanets, numbering in the thousands, have been discovered by NASA's Kepler space telescope, which uses a different strategy called the transit method. Kepler's cone-shaped field of view is shown in pink/orange. Ground-based telescopes, which use the transit and other planet-hunting methods, have discovered many exoplanets close to home, as shown by the pink/orange circle around the sun. http://photojournal.jpl.nasa.gov/catalog/PIA19333
A new direction for dark matter research: intermediate-mass compact halo objects

NASA Astrophysics Data System (ADS)

Chapline, George F.; Frampton, Paul H.

2016-11-01

The failure to find evidence for elementary particles that could serve as the constituents of dark matter brings to mind suggestions that dark matter might consist of massive compact objects (MACHOs). In particular, it has recently been argued that MACHOs with masses > 15Msolar may have been prolifically produced at the onset of the big bang. Although a variety of astrophysical signatures for primordial MACHOs with masses in this range have been discussed in the literature, we favor a strategy that uses the potential for magnification of stars outside our galaxy due to gravitational microlensing of these stars by MACHOs in the halo of our galaxy. We point out that the effect of the motion of the Earth on the shape of the micro-lensing brightening curves provides a promising approach to testing over the course of next several years the hypothesis that dark matter consists of massive compact objects.
On the Induced Gravitational Collapse

NASA Astrophysics Data System (ADS)

Becerra, Laura M.; Bianco, Carlo; Fryer, Chris; Rueda, Jorge; Ruffini, Remo

2018-01-01

The induced gravitational collapse (IGC) paradigm has been applied to explain the long gamma ray burst (GRB) associated with type Ic supernova, and recently the Xray flashes (XRFs). The progenitor is a binary systems of a carbon-oxygen core (CO) and a neutron star (NS). The CO core collapses and undergoes a supernova explosion which triggers the hypercritical accretion onto the NS companion (up to 10-2 M⊙s-1). For the binary driven hypernova (BdHNe), the binary system is enough bound, the NS reach its critical mass, and collapse to a black hole (BH) with a GRB emission characterized by an isotropic energy Eiso > 1052 erg. Otherwise, for binary systems with larger binary separations, the hypercritical accretion onto the NS is not sufficient to induced its gravitational collapse, a X-ray flash is produced with Eiso < 1052 erg. We're going to focus in identify the binary parameters that limits the BdHNe systems with the XRFs systems.
Application of wavelet analysis to estimation of parameters of the gravitational-wave signal from a coalescing binary

NASA Astrophysics Data System (ADS)

Królak, Andrzej; Trzaskoma, Pawel

1996-05-01

Application of wavelet analysis to the estimation of parameters of the broad-band gravitational-wave signal emitted by a binary system is investigated. A method of instantaneous frequency extraction first proposed in this context by Innocent and Vinet is used. The gravitational-wave signal from a binary is investigated from the point of view of signal analysis theory and it is shown that such a signal is characterized by a large time - bandwidth product. This property enables the extraction of frequency modulation from the wavelet transform of the signal. The wavelet transform of the chirp signal from a binary is calculated analytically. Numerical simulations with the noisy chirp signal are performed. The gravitational-wave signal from a binary is taken in the quadrupole approximation and it is buried in noise corresponding to three different values of the signal-to-noise ratio and the wavelet method to extract the frequency modulation of the signal is applied. Then, from the frequency modulation, the chirp mass parameter of the binary is estimated. It is found that the chirp mass can be estimated to a good accuracy, typically of the order of (20/0264-9381/13/5/006/img5% where 0264-9381/13/5/006/img6 is the optimal signal-to-noise ratio. It is also shown that the post-Newtonian effects in the gravitational wave signal from a binary can be discriminated to a satisfactory accuracy.
Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

NASA Astrophysics Data System (ADS)

Jacobson, Seth A.; Scheeres, Daniel J.

2011-07-01

We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thus creating a chaotic ternary system. The initially chaotic binary can be stabilized to create a synchronous binary by components of the fissioned secondary asteroid impacting the primary asteroid, solar gravitational perturbations, and mutual body tides. These results emphasize the importance of the initial component size distribution and configuration within the parent asteroid. NEAs may go through multiple binary cycles and many YORP-induced rotational fissions during their approximately 10 Myr lifetime in the inner Solar System. Rotational fission and the ensuing dynamics are responsible for all NEA systems including the most commonly observed synchronous binaries.
Search for Gravitational Waves from Low Mass Compact Binary Coalescence in LIGO's Sixth Science Run and Virgo's Science Runs 2 and 3

NASA Technical Reports Server (NTRS)

Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.;

2012-01-01

We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009, and October 20. 2010. We searched for signals from binaries with total mass between 2 and 25 Stellar Mass; this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass. including the results from previous LIGO and Virgo observations. The cumulative 90% confidence rate upper limits of the binary coalescence of binary neutron star, neutron star-black hole, and binary black hole systems are 1.3 x 10(exp -4), 3.1 x 10(exp -5), and 6.4 x 10(exp -6)/cu Mpc/yr, respectively. These upper limits are up to a factor 1.4 lower than previously derived limits. We also report on results from a blind injection challenge.

Search for gravitational waves from low mass compact binary coalescence in LIGO's sixth science run and Virgo's science runs 2 and 3

NASA Astrophysics Data System (ADS)

Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Agathos, M.; Ajith, P.; Allen, B.; Allen, G. S.; Amador Ceron, E.; Amariutei, D.; Amin, R. S.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Arain, M. A.; Araya, M. C.; Aston, S. M.; Astone, P.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P.; Ballardin, G.; Ballmer, S.; Barker, D.; Barone, F.; Barr, B.; Barriga, P.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Basti, A.; Batch, J.; Bauchrowitz, J.; Bauer, Th. S.; Bebronne, M.; Behnke, B.; Beker, M. G.; Bell, A. S.; Belletoile, A.; Belopolski, I.; Benacquista, M.; Berliner, J. M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biswas, R.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Blom, M.; Bock, O.; Bodiya, T. P.; Bogan, C.; Bondarescu, R.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, S.; Bosi, L.; Bouhou, B.; Braccini, S.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Breyer, J.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Brummit, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burguet–Castell, J.; Burmeister, O.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Calloni, E.; Camp, J. B.; Campsie, P.; Cannizzo, J.; Cannon, K.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chaibi, O.; Chalermsongsak, T.; Chalkley, E.; Charlton, P.; Chassande-Mottin, E.; Chelkowski, S.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H.; Christensen, N.; Chua, S. S. Y.; Chung, C. T. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, D. E.; Clark, J.; Clayton, J. H.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, A.; Conte, R.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M.; Coulon, J.-P.; Couvares, P.; Coward, D. M.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Cutler, R. M.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daudert, B.; Daveloza, H.; Davier, M.; Davies, G.; Daw, E. J.; Day, R.; Dayanga, T.; De Rosa, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; Del Pozzo, W.; del Prete, M.; Dent, T.; Dergachev, V.; DeRosa, R.; DeSalvo, R.; Dhurandhar, S.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Paolo Emilio, M.; Di Virgilio, A.; Díaz, M.; Dietz, A.; DiGuglielmo, J.; Donovan, F.; Dooley, K. L.; Dorsher, S.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dumas, J.-C.; Dwyer, S.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Endrőczi, G.; Engel, R.; Etzel, T.; Evans, K.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Farr, W.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Ferrante, I.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Flanigan, M.; Foley, S.; Forsi, E.; Forte, L. A.; Fotopoulos, N.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fulda, P. J.; Fyffe, M.; Galimberti, M.; Gammaitoni, L.; Ganija, M. R.; Garcia, J.; Garofoli, J. A.; Garufi, F.; Gáspár, M. E.; Gemme, G.; Geng, R.; Genin, E.; Gennai, A.; Gergely, L. Á.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gill, C.; Goetz, E.; Goggin, L. M.; González, G.; Gorodetsky, M. L.; Goßler, S.; Gouaty, R.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Gray, N.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Greverie, C.; Grosso, R.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gupta, R.; Gustafson, E. K.; Gustafson, R.; Ha, T.; Hage, B.; Hallam, J. M.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Hardt, A.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hartman, M. T.; Haughian, K.; Hayama, K.; Hayau, J.-F.; Heefner, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hendry, M. A.; Heng, I. S.; Heptonstall, A. W.; Herrera, V.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Hong, T.; Hooper, S.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Izumi, K.; Jacobson, M.; Jang, H.; Jaranowski, P.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kamaretsos, I.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kells, W.; Keppel, D. G.; Keresztes, Z.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, B.; Kim, C.; Kim, D.; Kim, H.; Kim, K.; Kim, N.; Kim, Y.-M.; King, P. J.; Kinsey, M.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kokeyama, K.; Kondrashov, V.; Kopparapu, R.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, R.; Kwee, P.; Lam, P. K.; Landry, M.; Lang, M.; Lantz, B.; Lastzka, N.; Lawrie, C.; Lazzarini, A.; Leaci, P.; Lee, C. H.; Lee, H. M.; Leindecker, N.; Leong, J. R.; Leonor, I.; Leroy, N.; Letendre, N.; Li, J.; Li, T. G. F.; Liguori, N.; Lindquist, P. E.; Lockerbie, N. A.; Lodhia, D.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Luan, J.; Lubinski, M.; Lück, H.; Lundgren, A. P.; Macdonald, E.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Mageswaran, M.; Mailand, K.; Majorana, E.; Maksimovic, I.; Man, N.; Mandel, I.; Mandic, V.; Mantovani, M.; Marandi, A.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Masserot, A.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McKechan, D. J. A.; Meadors, G. D.; Mehmet, M.; Meier, T.; Melatos, A.; Melissinos, A. C.; Mendell, G.; Menendez, D.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Michel, C.; Milano, L.; Miller, J.; Minenkov, Y.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Miyakawa, O.; Moe, B.; Moesta, P.; Mohan, M.; Mohanty, S. D.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morgia, A.; Mori, T.; Mosca, S.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Müller-Ebhardt, H.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nash, T.; Naticchioni, L.; Nawrodt, R.; Necula, V.; Nelson, J.; Newton, G.; Nishizawa, A.; Nocera, F.; Nolting, D.; Nuttall, L.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Oldenburg, R. G.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Page, A.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patel, P.; Pedraza, M.; Peiris, P.; Pekowsky, L.; Penn, S.; Peralta, C.; Perreca, A.; Persichetti, G.; Phelps, M.; Pickenpack, M.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Plissi, M. V.; Poggiani, R.; Pöld, J.; Postiglione, F.; Prato, M.; Predoi, V.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Quetschke, V.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Rakhmanov, M.; Ramet, C. R.; Rankins, B.; Rapagnani, P.; Raymond, V.; Re, V.; Redwine, K.; Reed, C. M.; Reed, T.; Regimbau, T.; Reid, S.; Reitze, D. H.; Ricci, F.; Riesen, R.; Riles, K.; Robertson, N. A.; Robinet, F.; Robinson, C.; Robinson, E. L.; Rocchi, A.; Roddy, S.; Rodriguez, C.; Rodruck, M.; Rolland, L.; Rollins, J.; Romano, J. D.; Romano, R.; Romie, J. H.; Rosińska, D.; Röver, C.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Ryll, H.; Sainathan, P.; Sakosky, M.; Salemi, F.; Samblowski, A.; Sammut, L.; Sancho de la Jordana, L.; Sandberg, V.; Sankar, S.; Sannibale, V.; Santamaría, L.; Santiago-Prieto, I.; Santostasi, G.; Sassolas, B.; Sathyaprakash, B. S.; Sato, S.; Saulson, P. R.; Savage, R. L.; Schilling, R.; Schlamminger, S.; Schnabel, R.; Schofield, R. M. S.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Searle, A. C.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sergeev, A.; Shaddock, D. A.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sibley, A.; Siemens, X.; Sigg, D.; Singer, A.; Singer, L.; Sintes, A. M.; Skelton, G.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, N. D.; Smith, R. J. E.; Somiya, K.; Sorazu, B.; Soto, J.; Speirits, F. C.; Sperandio, L.; Stefszky, M.; Stein, A. J.; Steinert, E.; Steinlechner, J.; Steinlechner, S.; Steplewski, S.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S.; Stroeer, A. S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sung, M.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Taffarello, L.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, J. R.; Taylor, R.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Thüring, A.; Titsler, C.; Tokmakov, K. V.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C.; Torrie, C. I.; Tournefier, E.; Travasso, F.; Traylor, G.; Trias, M.; Tseng, K.; Tucker, E.; Ugolini, D.; Urbanek, K.; Vahlbruch, H.; Vajente, G.; Vallisneri, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van Veggel, A. A.; Vass, S.; Vasuth, M.; Vaulin, R.; Vavoulidis, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Veltkamp, C.; Verkindt, D.; Vetrano, F.; Viceré, A.; Villar, A. E.; Vinet, J.-Y.; Vitale, S.; Vitale, S.; Vocca, H.; Vorvick, C.; Vyatchanin, S. P.; Wade, A.; Waldman, S. J.; Wallace, L.; Wan, Y.; Wang, X.; Wang, Z.; Wanner, A.; Ward, R. L.; Was, M.; Wei, P.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wen, S.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D.; Whiting, B. F.; Wilkinson, C.; Willems, P. A.; Williams, H. R.; Williams, L.; Willke, B.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Wooley, R.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yamamoto, K.; Yang, H.; Yeaton-Massey, D.; Yoshida, S.; Yu, P.; Yvert, M.; Zadroźny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, F.; Zhang, L.; Zhang, W.; Zhang, Z.; Zhao, C.; Zotov, N.; Zucker, M. E.; Zweizig, J.

2012-04-01

We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009, and October 20, 2010. We searched for signals from binaries with total mass between 2 and 25M⊙; this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass, including the results from previous LIGO and Virgo observations. The cumulative 90% confidence rate upper limits of the binary coalescence of binary neutron star, neutron star-black hole, and binary black hole systems are 1.3×10-4, 3.1×10-5, and 6.4×10-6Mpc-3yr-1, respectively. These upper limits are up to a factor 1.4 lower than previously derived limits. We also report on results from a blind injection challenge.
MOA-2008-BLG-379Lb: A massive planet from a high magnification event with a faint source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, D.; Sumi, T.; Fukagawa, M.

2014-01-10

We report on the analysis of the high microlensing event MOA-2008-BLG-379, which has a strong microlensing anomaly at its peak due to a massive planet with a mass ratio of q = 6.9 × 10{sup –3}. Because the faint source star crosses the large resonant caustic, the planetary signal dominates the light curve. This is unusual for planetary microlensing events, and as a result, the planetary nature of this light curve was not immediately noticed. The planetary nature of the event was found when the Microlensing Observations in Astrophysics (MOA) Collaboration conducted a systematic study of binary microlensing events previouslymore » identified by the MOA alert system. We have conducted a Bayesian analysis based on a standard Galactic model to estimate the physical parameters of the lens system. This yields a host star mass of M{sub L}=3.3{sub −1.2}{sup +1.7} M{sub ⊙} orbited by a planet of mass m{sub P}=0.56{sub −0.27}{sup +0.24} M{sub Jup} at an orbital separation of a=3.3{sub −1.2}{sup +1.3} AU at a distance of D{sub L}=4.1{sub −1.9}{sup +1.7} kpc. The faint source magnitude of I {sub S} = 21.30 and relatively high lens-source relative proper motion of μ{sub rel} = 7.6 ± 1.6 mas yr{sup –1} imply that high angular resolution adaptive optics or Hubble Space Telescope observations are likely to be able to detect the source star, which would determine the masses and distance of the planet and its host star.« less
Spitzer Observations of OGLE-2015-BLG-1212 Reveal a New Path toward Breaking Strong Microlens Degeneracies

NASA Technical Reports Server (NTRS)

Bozza, V.; Shvartzvald, Y.; Udalski, A.; Novati, S.Calchi; Bond, I. A.; Han, C.; Hundertmark, M.; Poleski, R.; Pawlak, M.; Szymanski, M. K.;

2016-01-01

Spitzer microlensing parallax observations of OGLE-2015-BLG-1212 decisively break a degeneracy between planetary and binary solutions that is somewhat ambiguous when only ground-based data are considered. Only eight viable models survive out of an initial set of 32 local minima in the parameter space. These models clearly indicate that the lens is a stellar binary system possibly located within the bulge of our Galaxy, ruling out the planetary alternative. We argue that several types of discrete degeneracies can be broken via such space-based parallax observations.

A Microlensing Analysis of the Central Engine in the Lensed Quasar WFI J2033-4723

NASA Astrophysics Data System (ADS)

Hyer, Gregory Edward; Morgan, Christopher; Bonvin, Vivien; Courbin, Fredric; Kochanek, Christopher; Falco, Emilio

2018-01-01

We report a detection of uncorrelated variability in 12 season optical light curves of the gravitationally lensed quasar WFI J2033-4723 from the 1.3m SMARTS telescope at CTIO and the 1.5m EULER telescope in La Silla. We analyzed this variability using the Monte Carlo technique of Kochanek (2004) to yield the first measurement of the size of this quasar’s accretion disk.
Topics in the Detection of Gravitational Waves from Compact Binary Inspirals

NASA Astrophysics Data System (ADS)

Kapadia, Shasvath Jagat

Orbiting compact binaries - such as binary black holes, binary neutron stars and neutron star-black hole binaries - are among the most promising sources of gravitational waves observable by ground-based interferometric detectors. Despite numerous sophisticated engineering techniques, the gravitational wave signals will be buried deep within noise generated by various instrumental and environmental processes, and need to be extracted via a signal processing technique referred to as matched filtering. Matched filtering requires large banks of signal templates that are faithful representations of the true gravitational waveforms produced by astrophysical binaries. The accurate and efficient production of templates is thus crucial to the success of signal processing and data analysis. To that end, the dissertation presents a numerical technique that calibrates existing analytical (Post-Newtonian) waveforms, which are relatively inexpensive, to more accurate fiducial waveforms that are computationally expensive to generate. The resulting waveform family is significantly more accurate than the analytical waveforms, without incurring additional computational costs of production. Certain kinds of transient background noise artefacts, called "glitches'', can masquerade as gravitational wave signals for short durations and throw-off the matched-filter algorithm. Identifying glitches from true gravitational wave signals is a highly non-trivial exercise in data analysis which has been attempted with varying degrees of success. We present here a machine-learning based approach that exploits the various attributes of glitches and signals within detector data to provide a classification scheme that is a significant improvement over previous methods. The dissertation concludes by investigating the possibility of detecting a non-linear DC imprint, called the Christodoulou memory, produced in the arms of ground-based interferometers by the recently detected gravitational waves. The memory, which is even smaller in amplitude than the primary (detected) gravitational waves, will almost certainly not be seen in the current detection event. Nevertheless, future space-based detectors will likely be sensitive enough to observe the memory.
Discovery and Characterization of a Caustic Crossing Microlensing Event in the Small Magellanic Cloud

NASA Astrophysics Data System (ADS)

Alcock, C.; Allsman, R. A.; Alves, D.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Drake, A. J.; Freeman, K. C.; Griest, K.; King, L. J.; Lehner, M. J.; Marshall, S. L.; Minniti, D.; Peterson, B. A.; Pratt, M. R.; Quinn, P. J.; Rhie, S. H.; Rodgers, A. W.; Stetson, P. B.; Stubbs, C. W.; Sutherland, W.; Tomaney, A.; Vandehei, T.

1999-06-01

We present photometric observations and analysis of the second microlensing event detected toward the Small Magellanic Cloud (SMC), MACHO Alert 98-SMC-1. This event was detected early enough to allow intensive observation of the light curve. These observations revealed 98-SMC-1 to be the first caustic crossing binary microlensing event toward the Magellanic Clouds to be discovered in progress. Frequent coverage of the evolving light curve allowed an accurate prediction for the date of the source crossing out of the lens caustic structure. The caustic crossing temporal width, along with the angular size of the source star, measures the proper motion of the lens with respect to the source and thus allows an estimate of the location of the lens. Lenses located in the Galactic halo would have a velocity projected to the SMC of v̂~1500 kms-1, while an SMC lens would typically have v̂~60 kms-1. The event light curve allows us to obtain a unique fit to the parameters of the binary lens and to estimate the proper motion of the lensing system. We have performed a joint fit to the MACHO/GMAN data presented here, including recent EROS data of this event from Afonso and collaborators. These joint data are sufficient to constrain the time t* for the lens to move an angle equal to the source angular radius: t*=0.116+/-0.010 days. We estimate a radius for the lensed source of R*=1.1+/-0.1 Rsolar from its unblended color and magnitude. This yields a projected velocity of v̂=76+/-10 kms-1. Only 0.12% of halo lenses would be expected to have a v̂ value at least as small as this, while 38% of SMC lenses would be expected to have v̂ as large as this. This implies that the lensing system is more likely to reside in the SMC than in the Galactic halo. Similar observations of future Magellanic Cloud microlensing events will help to determine the contribution of MACHOS to the Galaxy's dark halo.
First low-latency LIGO+Virgo search for binary inspirals and their electromagnetic counterparts

NASA Astrophysics Data System (ADS)

Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M.; Accadia, T.; Acernese, F.; Adams, C.; Adhikari, R.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Ajith, P.; Allen, B.; Amador Ceron, E.; Amariutei, D.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Arain, M. A.; Araya, M. C.; Aston, S. M.; Astone, P.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P.; Ballardin, G.; Ballmer, S.; Barayoga, J. C. B.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Basti, A.; Batch, J.; Bauchrowitz, J.; Bauer, Th. S.; Bebronne, M.; Beck, D.; Behnke, B.; Bejger, M.; Beker, M. G.; Bell, A. S.; Belletoile, A.; Belopolski, I.; Benacquista, M.; Berliner, J. M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biswas, R.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Blom, M.; Bock, O.; Bodiya, T. P.; Bogan, C.; Bondarescu, R.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, S.; Bosi, L.; Bouhou, B.; Braccini, S.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Breyer, J.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burguet-Castell, J.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Calloni, E.; Camp, J. B.; Campsie, P.; Cannizzo, J.; Cannon, K.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Carbone, L.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chaibi, O.; Chalermsongsak, T.; Charlton, P.; Chassande-Mottin, E.; Chelkowski, S.; Chen, W.; Chen, X.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Chow, J.; Christensen, N.; Chua, S. S. Y.; Chung, C. T. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, D. E.; Clark, J.; Clayton, J. H.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colacino, C. N.; Colas, J.; Colla, A.; Colombini, M.; Conte, A.; Conte, R.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M.; Coulon, J.-P.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Cutler, R. M.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daudert, B.; Daveloza, H.; Davier, M.; Daw, E. J.; Day, R.; Dayanga, T.; De Rosa, R.; DeBra, D.; Debreczeni, G.; Del Pozzo, W.; del Prete, M.; Dent, T.; Dergachev, V.; DeRosa, R.; DeSalvo, R.; Dhurandhar, S.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Emilio, M. Di Paolo; Di Virgilio, A.; Díaz, M.; Dietz, A.; Donovan, F.; Dooley, K. L.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dumas, J.-C.; Dwyer, S.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Endrőczi, G.; Engel, R.; Etzel, T.; Evans, K.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Feroz, F.; Ferrante, I.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Flanigan, M.; Foley, S.; Forsi, E.; Forte, L. A.; Fotopoulos, N.; Fournier, J.-D.; Franc, J.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fujimoto, M.-K.; Fulda, P. J.; Fyffe, M.; Gair, J.; Galimberti, M.; Gammaitoni, L.; Garcia, J.; Garufi, F.; Gáspár, M. E.; Gemme, G.; Geng, R.; Genin, E.; Gennai, A.; Gergely, L. Á.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gil-Casanova, S.; Gill, C.; Gleason, J.; Goetz, E.; Goggin, L. M.; González, G.; Gorodetsky, M. L.; Goßler, S.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Gray, N.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Greverie, C.; Grosso, R.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gupta, R.; Gustafson, E. K.; Gustafson, R.; Ha, T.; Hallam, J. M.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hartman, M. T.; Haughian, K.; Hayama, K.; Hayau, J.-F.; Heefner, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hendry, M. A.; Heng, I. S.; Heptonstall, A. W.; Herrera, V.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Holtrop, M.; Hong, T.; Hooper, S.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Izumi, K.; Jacobson, M.; James, E.; Jang, Y. J.; Jaranowski, P.; Jesse, E.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kasturi, R.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kelley, D.; Kells, W.; Keppel, D. G.; Keresztes, Z.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, B. K.; Kim, C.; Kim, H.; Kim, K.; Kim, N.; Kim, Y. M.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D.; Kranz, O.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, R.; Kwee, P.; Lam, P. K.; Landry, M.; Lantz, B.; Lastzka, N.; Lawrie, C.; Lazzarini, A.; Leaci, P.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Leong, J. R.; Leonor, I.; Leroy, N.; Letendre, N.; Li, J.; Li, T. G. F.; Liguori, N.; Lindquist, P. E.; Liu, Y.; Liu, Z.; Lockerbie, N. A.; Lodhia, D.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Luan, J.; Lubinski, M.; Lück, H.; Lundgren, A. P.; Macdonald, E.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Mageswaran, M.; Mailand, K.; Majorana, E.; Maksimovic, I.; Man, N.; Mandel, I.; Mandic, V.; Mantovani, M.; Marandi, A.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Masserot, A.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McKechan, D. J. A.; McWilliams, S.; Meadors, G. D.; Mehmet, M.; Meier, T.; Melatos, A.; Melissinos, A. C.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Michel, C.; Milano, L.; Miller, J.; Minenkov, Y.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Miyakawa, O.; Moe, B.; Mohan, M.; Mohanty, S. D.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morgia, A.; Mori, T.; Morriss, S. R.; Mosca, S.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Müller-Ebhardt, H.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nash, T.; Naticchioni, L.; Necula, V.; Nelson, J.; Neri, I.; Newton, G.; Nguyen, T.; Nishizawa, A.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E.; Nuttall, L.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Page, A.; Pagliaroli, G.; Palladino, L.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Parisi, M.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patel, P.; Pedraza, M.; Peiris, P.; Pekowsky, L.; Penn, S.; Perreca, A.; Persichetti, G.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pietka, M.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Plissi, M. V.; Poggiani, R.; Pöld, J.; Postiglione, F.; Prato, M.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Quetschke, V.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Rakhmanov, M.; Rankins, B.; Rapagnani, P.; Raymond, V.; Re, V.; Redwine, K.; Reed, C. M.; Reed, T.; Regimbau, T.; Reid, S.; Reitze, D. H.; Ricci, F.; Riesen, R.; Riles, K.; Robertson, N. A.; Robinet, F.; Robinson, C.; Robinson, E. L.; Rocchi, A.; Roddy, S.; Rodriguez, C.; Rodruck, M.; Rolland, L.; Rollins, J. G.; Romano, J. D.; Romano, R.; Romie, J. H.; Rosińska, D.; Röver, C.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sainathan, P.; Salemi, F.; Sammut, L.; Sandberg, V.; Sannibale, V.; Santamaría, L.; Santiago-Prieto, I.; Santostasi, G.; Sassolas, B.; Sathyaprakash, B. S.; Sato, S.; Saulson, P. R.; Savage, R. L.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Seifert, F.; Sellers, D.; Sentenac, D.; Sergeev, A.; Shaddock, D. A.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sibley, A.; Siemens, X.; Sigg, D.; Singer, A.; Singer, L.; Sintes, A. M.; Skelton, G. R.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Somiya, K.; Sorazu, B.; Soto, J.; Speirits, F. C.; Sperandio, L.; Stefszky, M.; Stein, A. J.; Stein, L. C.; Steinert, E.; Steinlechner, J.; Steinlechner, S.; Steplewski, S.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S. E.; Stroeer, A. S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sung, M.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Taffarello, L.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, J. R.; Taylor, R.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Thüring, A.; Tokmakov, K. V.; Tomlinson, C.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C.; Torrie, C. I.; Tournefier, E.; Travasso, F.; Traylor, G.; Tseng, K.; Ugolini, D.; Vahlbruch, H.; Vajente, G.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van Veggel, A. A.; Vass, S.; Vasuth, M.; Vaulin, R.; Vavoulidis, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Veltkamp, C.; Verkindt, D.; Vetrano, F.; Viceré, A.; Villar, A. E.; Vinet, J.-Y.; Vitale, S.; Vocca, H.; Vorvick, C.; Vyatchanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Waldman, S. J.; Wallace, L.; Wan, Y.; Wang, M.; Wang, X.; Wang, Z.; Wanner, A.; Ward, R. L.; Was, M.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Wilkinson, C.; Willems, P. A.; Williams, L.; Williams, R.; Willke, B.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Wooley, R.; Worden, J.; Yakushin, I.; Yamamoto, H.; Yamamoto, K.; Yancey, C. C.; Yang, H.; Yeaton-Massey, D.; Yoshida, S.; Yu, P.; Yvert, M.; Zadrożny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, F.; Zhang, L.; Zhang, W.; Zhao, C.; Zotov, N.; Zucker, M. E.; Zweizig, J.

2012-05-01

Aims: The detection and measurement of gravitational-waves from coalescing neutron-star binary systems is an important science goal for ground-based gravitational-wave detectors. In addition to emitting gravitational-waves at frequencies that span the most sensitive bands of the LIGO and Virgo detectors, these sources are also amongst the most likely to produce an electromagnetic counterpart to the gravitational-wave emission. A joint detection of the gravitational-wave and electromagnetic signals would provide a powerful new probe for astronomy. Methods: During the period between September 19 and October 20, 2010, the first low-latency search for gravitational-waves from binary inspirals in LIGO and Virgo data was conducted. The resulting triggers were sent to electromagnetic observatories for followup. We describe the generation and processing of the low-latency gravitational-wave triggers. The results of the electromagnetic image analysis will be described elsewhere. Results: Over the course of the science run, three gravitational-wave triggers passed all of the low-latency selection cuts. Of these, one was followed up by several of our observational partners. Analysis of the gravitational-wave data leads to an estimated false alarm rate of once every 6.4 days, falling far short of the requirement for a detection based solely on gravitational-wave data.
OGLE-III Microlensing Events and the Structure of the Galactic Bulge

NASA Astrophysics Data System (ADS)

Wyrzykowski, Łukasz; Rynkiewicz, Alicja E.; Skowron, Jan; Kozłowski, Szymon; Udalski, Andrzej; Szymański, Michał K.; Kubiak, Marcin; Soszyński, Igor; Pietrzyński, Grzegorz; Poleski, Radosław; Pietrukowicz, Paweł; Pawlak, Michał

2015-01-01

We present and study the largest and most comprehensive catalog of microlensing events ever constructed. The sample of standard microlensing events comprises 3718 unique events from 2001-2009 with 1409 events that had not been detected before in real-time by the Early Warning System of the Optical Gravitational Lensing Experiment. The search pipeline uses machine learning algorithms to help find rare phenomena among 150 million objects and to derive the detection efficiency. Applications of the catalog can be numerous, from analyzing individual events to large statistical studies of the Galactic mass, kinematics distributions, and planetary abundances. We derive maps of the mean Einstein ring crossing time of events spanning 31 deg2 toward the Galactic center and compare the observed distributions with the most recent models. We find good agreement within the observed region and we see the signature of the tilt of the bar in the microlensing data. However, the asymmetry of the mean timescales seems to rise more steeply than predicted, indicating either a somewhat different orientation of the bar or a larger bar width. The map of events with sources in the Galactic bulge shows a dependence of the mean timescale on the Galactic latitude, signaling an increasing contribution from disk lenses closer to the plane relative to the height of the disk. Our data present a perfect set for comparing and enhancing new models of the central parts of the Milky Way and creating a three-dimensional picture of the Galaxy. Based on observations obtained with the 1.3 m Warsaw telescope at the Las Campanas Observatory of the Carnegie Institution for Science.
OGLE-2003-BLG-238: Microlensing Mass Estimate of an Isolated Star

NASA Astrophysics Data System (ADS)

Jiang, Guangfei; DePoy, D. L.; Gal-Yam, A.; Gaudi, B. S.; Gould, A.; Han, C.; Lipkin, Y.; Maoz, D.; Ofek, E. O.; Park, B.-G.; Pogge, R. W.; MuFun Collaboration; Udalski, A.; Kubiak, M.; Szymański, M. K.; Szewczyk, O.; Żebruń, K.; Wyrzykowski, Ł.; Soszyński, I.; Pietrzyński, G.; OGLE Collaboration; Albrow, M. D.; Beaulieu, J.-P.; Caldwell, J. A. R.; Cassan, A.; Coutures, C.; Dominik, M.; Donatowicz, J.; Fouqué, P.; Greenhill, J.; Hill, K.; Horne, K.; Jørgensen, S. F.; Jørgensen, U. G.; Kane, S.; Kubas, D.; Martin, R.; Menzies, J.; Pollard, K. R.; Sahu, K. C.; Wambsganss, J.; Watson, R.; Williams, A.; PLANET Collaboration

2004-12-01

Microlensing is the only known direct method to measure the masses of stars that lack visible companions. In terms of microlensing observables, the mass is given by M=(c2/4G)rEθE and so requires the measurement of both the angular Einstein radius θE and the projected Einstein radius rE. Simultaneous measurement of these two parameters is extremely rare. Here we analyze OGLE-2003-BLG-238, a spectacularly bright (Imin=10.3), high-magnification (Amax=170) microlensing event. Pronounced finite-source effects permit a measurement of θE=650μas. Although the timescale of the event is only tE=38days, one can still obtain weak constraints on the microlens parallax: 4.4AU

Improvements in Gravitational-wave Sky Localization with Expanded Networks of Interferometers

NASA Astrophysics Data System (ADS)

Pankow, Chris; Chase, Eve A.; Coughlin, Scott; Zevin, Michael; Kalogera, Vassiliki

2018-02-01

A milestone of multi-messenger astronomy has been achieved with the detection of gravitational waves from a binary neutron star merger accompanied by observations of several associated electromagnetic counterparts. Joint observations can reveal details of the engines that drive the electromagnetic and gravitational-wave emission. However, locating and identifying an electromagnetic counterpart to a gravitational-wave event is heavily reliant on localization of the source through gravitational-wave information. We explore the sky localization of a simulated set of neutron star mergers as the worldwide network of gravitational-wave detectors evolves through the next decade, performing the first such study for neutron star–black hole binary sources. Currently, three detectors are observing with additional detectors in Japan and India expected to become operational in the coming years. With three detectors, we recover a median neutron star–black hole binary sky localization of 60 deg2 at the 90% credible level. As all five detectors become operational, sources can be localized to a median of 11 deg2 on the sky.
The nightmare scenario: measuring the stochastic gravitational wave background from stalling massive black hole binaries with pulsar timing arrays

NASA Astrophysics Data System (ADS)

Dvorkin, Irina; Barausse, Enrico

2017-10-01

Massive black hole binaries, formed when galaxies merge, are among the primary sources of gravitational waves targeted by ongoing pulsar timing array (PTA) experiments and the upcoming space-based Laser Interferometer Space Antenna (LISA) interferometer. However, their formation and merger rates are still highly uncertain. Recent upper limits on the stochastic gravitational wave background obtained by PTAs are starting to be in marginal tension with theoretical models for the pairing and orbital evolution of these systems. This tension can be resolved by assuming that these binaries are more eccentric or interact more strongly with the environment (gas and stars) than expected, or by accounting for possible selection biases in the construction of the theoretical models. However, another (pessimistic) possibility is that these binaries do not merge at all, but stall at large (˜pc) separations. We explore this extreme scenario by using a semi-analytic galaxy formation model including massive black holes (isolated and in binaries), and show that future generations of PTAs will detect the stochastic gravitational wave background from the massive black hole binary population within 10-15 yr of observations, even in the `nightmare scenario' in which all binaries stall at the hardening radius. Moreover, we argue that this scenario is too pessimistic, because our model predicts the existence of a subpopulation of binaries with small mass ratios (q ≲ 10-3) that should merge within a Hubble time simply as a result of gravitational wave emission. This subpopulation will be observable with large signal-to-noise ratios by future PTAs thanks to next-generation radio telescopes such as Square Kilometre Array or Five-hundred-meter Aperture Spherical Telescope, and possibly by LISA.
An axion-like scalar field environment effect on binary black hole merger

NASA Astrophysics Data System (ADS)

Yang, Qing; Ji, Li-Wei; Hu, Bin; Cao, Zhou-Jian; Cai, Rong-Gen

2018-06-01

The environment, such as an accretion disk, could modify the signal of the gravitational wave from astrophysical black hole binaries. In this article, we model the matter field around intermediate-mass binary black holes by means of an axion-like scalar field and investigate their joint evolution. In detail, we consider equal mass binary black holes surrounded by a shell of axion-like scalar field both in spherically symmetric and non-spherically symmetric cases, and with different strengths of the scalar field. Our result shows that the environmental scalar field could essentially modify the dynamics. Firstly, in the spherically symmetric case, with increase of the scalar field strength, the number of circular orbits for the binary black hole is reduced. This means that the scalar field could significantly accelerate the merger process. Secondly, once the scalar field strength exceeds a certain critical value, the scalar field could collapse into a third black hole with its mass being larger than that of the binary. Consequently, the new black hole that collapses from the environmental scalar field could accrete the binary promptly and the binary collides head-on with each other. In this process, there is almost no quadrupole signal produced, and, consequently, the gravitational wave is greatly suppressed. Thirdly, when the scalar field strength is relatively smaller than the critical value, the black hole orbit could develop eccentricity through accretion of the scalar field. Fourthly, during the initial stage of the inspiral, the gravitational attractive force from the axion-like scalar field could induce a sudden turn in the binary orbits, hence resulting in a transient wiggle in the gravitational waveform. Finally, in the non-spherical case, the scalar field could gravitationally attract the binary moving toward the center of mass for the scalar field and slow down the merger process.
A Detection Pipeline for Galactic Binaries in LISA Data

NASA Technical Reports Server (NTRS)

Littenberg, Tyson B.

2012-01-01

The Galaxy is suspected to contain hundreds of millions of binary white dwarf systems, a large fraction of which will have sufficiently small orbital period to emit gravitational radiation in band for space-based gravitational wave detectors such as the Laser Interferometer Space Antenna (LISA). LISA's main science goal is the detection of cosmological events (supermassive black hole mergers) etc.) however the gravitational signal from the galaxy will be the dominant contribution to the data - including instrumental noise - over approximately two decades in frequency. The catalogue of detectable binary systems will serve as an unparalleled means of studying the Galaxy. Furthermore, to maximize the scientific return from the mission, the data must be "cleansed" of the galactic foreground. We will present an algorithm that can accurately resolve and subtract greater than or equal to 10000 of these sources from simulated data supplied by the Mock LISA Data Challenge Task Force. Using the time evolution of the gravitational wave frequency, we will reconstruct the position of the recovered binaries and show how LISA will sample the entire compact binary population in the Galaxy.
Rapid Monte Carlo Simulation of Gravitational Wave Galaxies

NASA Astrophysics Data System (ADS)

Breivik, Katelyn; Larson, Shane L.

2015-01-01

With the detection of gravitational waves on the horizon, astrophysical catalogs produced by gravitational wave observatories can be used to characterize the populations of sources and validate different galactic population models. Efforts to simulate gravitational wave catalogs and source populations generally focus on population synthesis models that require extensive time and computational power to produce a single simulated galaxy. Monte Carlo simulations of gravitational wave source populations can also be used to generate observation catalogs from the gravitational wave source population. Monte Carlo simulations have the advantes of flexibility and speed, enabling rapid galactic realizations as a function of galactic binary parameters with less time and compuational resources required. We present a Monte Carlo method for rapid galactic simulations of gravitational wave binary populations.
The Exoplanet Microlensing Survey by the Proposed WFIRST Observatory

NASA Technical Reports Server (NTRS)

Barry, Richard; Kruk, Jeffrey; Anderson, Jay; Beaulieu, Jean-Philippe; Bennett, David P.; Catanzarite, Joseph; Cheng, Ed; Gaudi, Scott; Gehrels, Neil; Kane, Stephen;

2012-01-01

The New Worlds, New Horizons report released by the Astronomy and Astrophysics Decadal Survey Board in 2010 listed the Wide Field Infrared Survey Telescope (WFIRST) as the highest-priority large space mission for the . coming decade. This observatory will provide wide-field imaging and slitless spectroscopy at near infrared wavelengths. The scientific goals are to obtain a statistical census of exoplanets using gravitational microlensing. measure the expansion history of and the growth of structure in the Universe by multiple methods, and perform other astronomical surveys to be selected through a guest observer program. A Science Definition Team has been established to assist NASA in the development of a Design Reference Mission that accomplishes this diverse array of science programs with a single observatory. In this paper we present the current WFIRST payload concept and the expected capabilities for planet detection. The observatory. with science goals that are complimentary to the Kepler exoplanet transit mission, is designed to complete the statistical census of planetary systems in the Galaxy, from habitable Earth-mass planets to free floating planets, including analogs to all of the planets in our Solar System except Mercury. The exoplanet microlensing survey will observe for 500 days spanning 5 years. This long temporal baseline will enable the determination of the masses for most detected exoplanets down to 0.1 Earth masses.

X-ray microlensing in the quadruply lensed quasar Q2237+0305

NASA Astrophysics Data System (ADS)

Zimmer, F.; Schmidt, R. W.; Wambsganss, J.

2011-05-01

We use archival data of NASA's Chandra X-ray telescope to compile an X-ray light curve of all four images of the quadruply lensed quasar Q2237+0305 (zQ= 1.695) from 2006 January to 2007 January. We fit simulated point spread functions to the four individual quasar images using Cash's C-statistic to account for the Poissonian nature of the X-ray signal. The quasar images display strong flux variations up to a factor of ˜4 within one month. We can disentangle the intrinsic quasar variability from flux variations due to gravitational microlensing by looking at the flux ratios of the individual quasar images. Doing this, we find evidence for microlensing in image A. In particular, the time sequence of the flux ratio A/B in the X-ray regime correlates with the corresponding sequence in the optical monitoring by OGLE in the V band. The amplitudes in the X-ray light curve are larger. For the most prominent peak, the increase of the X-ray ratio A/B is larger by a factor of ˜1.6 compared to the signal in the optical. In agreement with theory and other observations of multiply-imaged quasars, this suggests that the X-ray emission region of this quasar is significantly smaller than the optical emission region.
Accuracy of inference on the physics of binary evolution from gravitational-wave observations

NASA Astrophysics Data System (ADS)

Barrett, Jim W.; Gaebel, Sebastian M.; Neijssel, Coenraad J.; Vigna-Gómez, Alejandro; Stevenson, Simon; Berry, Christopher P. L.; Farr, Will M.; Mandel, Ilya

2018-04-01

The properties of the population of merging binary black holes encode some of the uncertain physics underlying the evolution of massive stars in binaries. The binary black hole merger rate and chirp-mass distribution are being measured by ground-based gravitational-wave detectors. We consider isolated binary evolution, and explore how accurately the physical model can be constrained with such observations by applying the Fisher information matrix to the merging black hole population simulated with the rapid binary-population synthesis code COMPAS. We investigate variations in four COMPAS parameters: common-envelope efficiency, kick-velocity dispersion, and mass-loss rates during the luminous blue variable and Wolf-Rayet stellar-evolutionary phases. We find that ˜1000 observations would constrain these model parameters to a fractional accuracy of a few per cent. Given the empirically determined binary black hole merger rate, we can expect gravitational-wave observations alone to place strong constraints on the physics of stellar and binary evolution within a few years. Our approach can be extended to use other observational data sets; combining observations at different evolutionary stages will lead to a better understanding of stellar and binary physics.
Accuracy of inference on the physics of binary evolution from gravitational-wave observations

NASA Astrophysics Data System (ADS)

Barrett, Jim W.; Gaebel, Sebastian M.; Neijssel, Coenraad J.; Vigna-Gómez, Alejandro; Stevenson, Simon; Berry, Christopher P. L.; Farr, Will M.; Mandel, Ilya

2018-07-01

The properties of the population of merging binary black holes encode some of the uncertain physics underlying the evolution of massive stars in binaries. The binary black hole merger rate and chirp-mass distribution are being measured by ground-based gravitational-wave detectors. We consider isolated binary evolution, and explore how accurately the physical model can be constrained with such observations by applying the Fisher information matrix to the merging black hole population simulated with the rapid binary-population synthesis code COMPAS. We investigate variations in four COMPAS parameters: common-envelope efficiency, kick-velocity dispersion and mass-loss rates during the luminous blue variable, and Wolf-Rayet stellar-evolutionary phases. We find that ˜1000 observations would constrain these model parameters to a fractional accuracy of a few per cent. Given the empirically determined binary black hole merger rate, we can expect gravitational-wave observations alone to place strong constraints on the physics of stellar and binary evolution within a few years. Our approach can be extended to use other observational data sets; combining observations at different evolutionary stages will lead to a better understanding of stellar and binary physics.
Gravitational radiation, inspiraling binaries, and cosmology

NASA Technical Reports Server (NTRS)

Chernoff, David F.; Finn, Lee S.

1993-01-01

We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitational-wave Observatory (LIGO)-like detector. Using realistic detector noise estimates, we characterize the rate of detections as a function of a threshold SNR Rho(0), H0, and the binary 'chirp' mass. For Rho(0) = 8, H0 = 100 km/s/Mpc, and 1.4 solar mass neutron star binaries, the sample has a median redshift of 0.22. Under the same assumptions but independent of H0, a conservative rate density of coalescing binaries implies LIGO will observe about 50/yr binary inspiral events. The precision with which H0 and the deceleration parameter q0 may be determined depends on the number of observed inspirals. For fixed mass binary systems, about 100 observations with Rho(0) = 10 in the LIGO will give H0 to 10 percent in an Einstein-DeSitter cosmology, and 3000 will give q0 to 20 percent. For the conservative rate density of coalescing binaries, 100 detections with Rho(0) = 10 will require about 4 yrs.
OGLE-2016-BLG-0263Lb: Microlensing Detection of a Very Low-mass Binary Companion through a Repeating Event Channel

NASA Astrophysics Data System (ADS)

Han, C.; Udalski, A.; Gould, A.; Bond, I. A.; and; Albrow, M. D.; Chung, S.-J.; Jung, Y. K.; Ryu, Y.-H.; Shin, I.-G.; Yee, J. C.; Zhu, W.; Cha, S.-M.; Kim, S.-L.; Kim, D.-J.; Lee, C.-U.; Lee, Y.; Park, B.-G.; KMTNet Collaboration; Skowron, J.; Mróz, P.; Pietrukowicz, P.; Kozłowski, S.; Poleski, R.; Szymański, M. K.; Soszyński, I.; Ulaczyk, K.; Pawlak, M.; OGLE Collaboration; Abe, F.; Asakura, Y.; Barry, R.; Bennett, D. P.; Bhattacharya, A.; Donachie, M.; Evans, P.; Fukui, A.; Hirao, Y.; Itow, Y.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Ranc, C.; Rattenbury, N. J.; Saito, To.; Sharan, A.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Tristram, P. J.; Yamada, T.; Yamada, T.; Yonehara, A.; The MOA Collaboration

2017-10-01

We report the discovery of a planet-mass companion to the microlens OGLE-2016-BLG-0263L. Unlike most low-mass companions that were detected through perturbations to the smooth and symmetric light curves produced by the primary, the companion was discovered through the channel of a repeating event, in which the companion itself produced its own single-mass light curve after the event produced by the primary had ended. Thanks to the continuous coverage of the second peak by high-cadence surveys, the possibility of the repeating nature due to source binarity is excluded with a 96% confidence level. The mass of the companion estimated by a Bayesian analysis is {M}{{p}}={4.1}-2.5+6.5 {M}{{J}}. The projected primary-companion separation is {a}\\perp ={6.5}-1.9+1.3 au. The ratio of the separation to the snow-line distance of {a}\\perp /{a}{sl}˜ 15.4 corresponds to the region beyond Neptune, the outermost planet of the solar system. We discuss the importance of high-cadence surveys in expanding the range of microlensing detections of low-mass companions and future space-based microlensing surveys.
TCP J05074264+2447555 as a bright microlensing event due to a binary system with very low mass ratio component: hint for a new planetary system?

NASA Astrophysics Data System (ADS)

Nucita, A. A.; Licchelli, D.; De Paolis, F.; Ingrosso, G.; Strafella, F.

2017-11-01

The transient event labeled as TCP J05074264+2447555 (RA 05h07m42.64s, DEC +24°47'55.5" (J2000.0)) was first discovered by Kojima on UT 2017-10-25.688 in the Taurus region and suddenly recognized as something peculiar.
MiNDSTEp differential photometry of the gravitationally lensed quasars WFI 2033-4723 and HE 0047-1756: microlensing and a new time delay

NASA Astrophysics Data System (ADS)

Giannini, E.; Schmidt, R. W.; Wambsganss, J.; Alsubai, K.; Andersen, J. M.; Anguita, T.; Bozza, V.; Bramich, D. M.; Browne, P.; Calchi Novati, S.; Damerdji, Y.; Diehl, C.; Dodds, P.; Dominik, M.; Elyiv, A.; Fang, X.; Figuera Jaimes, R.; Finet, F.; Gerner, T.; Gu, S.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jessen-Hansen, J.; Jørgensen, U. G.; Juncher, D.; Kains, N.; Kerins, E.; Korhonen, H.; Liebig, C.; Lund, M. N.; Lundkvist, M. S.; Maier, G.; Mancini, L.; Masi, G.; Mathiasen, M.; Penny, M.; Proft, S.; Rabus, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Sahu, K.; Schäfer, S.; Schönebeck, F.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Vilela, C.; Wertz, O.; Zimmer, F.

2017-01-01

Aims: We present V and R photometry of the gravitationally lensed quasars WFI 2033-4723 and HE 0047-1756. The data were taken by the MiNDSTEp collaboration with the 1.54 m Danish telescope at the ESO La Silla observatory from 2008 to 2012. Methods: Differential photometry has been carried out using the image subtraction method as implemented in the HOTPAnTS package, additionally using GALFIT for quasar photometry. Results: The quasar WFI 2033-4723 showed brightness variations of order 0.5 mag in V and R during the campaign. The two lensed components of quasar HE 0047-1756 varied by 0.2-0.3 mag within five years. We provide, for the first time, an estimate of the time delay of component B with respect to A of Δt = (7.6 ± 1.8) days for this object. We also find evidence for a secular evolution of the magnitude difference between components A and B in both filters, which we explain as due to a long-duration microlensing event. Finally we find that both quasars WFI 2033-4723 and HE 0047-1756 become bluer when brighter, which is consistent with previous studies. Based on data collected by MiNDSTEp with the Danish 1.54 m telescope at the ESO La Silla observatory.
Measuring the Innermost Stable Circular Orbits of Supermassive Black Holes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chartas, G.; Zalesky, L.; Krawczynski, H.

We present a promising new technique, the g -distribution method, for measuring the inclination angle ( i ), the innermost stable circular orbit (ISCO), and the spin of a supermassive black hole. The g -distribution method uses measurements of the energy shifts in the relativistic iron line emitted by the accretion disk of a supermassive black hole due to microlensing by stars in a foreground galaxy relative to the g -distribution shifts predicted from microlensing caustic calculations. We apply the method to the gravitationally lensed quasars RX J1131–1231 ( z {sub s} = 0.658, z {sub l} = 0.295), QJmore » 0158–4325 ( z {sub s} = 1.294, z {sub l} = 0.317), and SDSS 1004+4112 ( z {sub s} = 1.734, z {sub l} = 0.68). For RX J1131−1231, our initial results indicate that r {sub ISCO} ≲ 8.5 gravitational radii ( r {sub g}) and i ≳ 55° (99% confidence level). We detect two shifted Fe lines in several observations, as predicted in our numerical simulations of caustic crossings. The current Δ E distribution of RX J1131–1231 is sparsely sampled, but further X-ray monitoring of RX J1131–1231 and other lensed quasars will provide improved constraints on the inclination angles, ISCO radii, and spins of the black holes of distant quasars.« less
Gravitational radiation from binary systems in alternative metric theories of gravity - Dipole radiation and the binary pulsar

NASA Technical Reports Server (NTRS)

Will, C. M.

1977-01-01

The generation of gravitational radiation in several currently viable metric theories of gravitation (Brans-Dicke, Rosen, Ni, and Lightman-Lee) is analyzed, and it is shown that these theories predict the emission of dipole gravitational radiation from systems containing gravitationally bound objects. In the binary system PSR 1913 + 16, this radiation results in a secular change in the orbital period of the system with a nominal magnitude of 3 parts in 100,000 per year. The size of the effect is proportional to the reduced mass of the system, to the square of the difference in (self-gravitational energy)/(mass) between the two components of the system, and to a parameter, xi, whose value varies from theory to theory. In general relativity xi equals 0, in Rosen's (1973) theory xi equals -20/3, and in Ni's (1973) theory xi equals -400/3. The current upper limit on such a secular period change is one part in 1 million per year. It is shown that further observations of the binary system that tighten this limit and that establish the masses of the components and the identity of the companion may provide a crucial test of otherwise viable alternatives to general relativity.
The gravitational-optical methods for examination of the hypothesis about galaxies and antigalaxies in the Universe

NASA Astrophysics Data System (ADS)

Gribov, I. A.; Trigger, S. A.

2018-01-01

The optical-gravitational methods for distinction between photons and antiphotons (galaxies, emitting photons and antigalaxies, emitting antiphotons) in the proposed hypothesis of totally gravitationally neutral (TGN)-Universe are considered. These methods are based on the extension of the earlier proposed the gravitationally neutral Universe concept, including now gravitational neutrality of vacuum. This concept contains (i) enlarged unbroken baryon-like, charge, parity and time and full ±M gr gravitational symmetries between all massive elementary particles-antiparticles, including (ia) ordinary matter (OM)-ordinary antimatter (OAM), (ib) dark matter (DM)-dark antimatter (DAM) and (ii) the resulting gravitational repulsion between equally presented (OM+DM)-galactic and (OAM+DAM)-antigalactic clusters, what spatially isolates and preserves their mutual annihilations in the large-scale TGN-Universe. It is assumed the gravitational balance not only between positive and negative gravitational masses of elementary particles and antiparticles, but also between all massless fields of the quantum field theory (QFT), including the opposite gravitational properties of photons and antiphotons, etc, realizing the totally gravitationally neutral vacuum in the QFT. These photons and antiphotons could be distinguishable optically-gravitationally, if one can observe a massive, deviating OM-star or a deviating (OM+DM)-galaxy from our galactic group, moving fast enough on the heavenly sphere, crossing the line directed to spatially separated far-remote galactic clusters (with the visible OM-markers, emitting photons) or antigalactic cluster (with the visible OAM-markers, emitting antiphotons). The deviations and gravitational microlensing with temporarily increased or decreased brightness of their OM and OAM rays will be opposite, indicating the galaxies and antigalaxies in the Universe.
Theory-Agnostic Constraints on Black-Hole Dipole Radiation with Multiband Gravitational-Wave Astrophysics.

PubMed

Barausse, Enrico; Yunes, Nicolás; Chamberlain, Katie

2016-06-17

The aLIGO detection of the black-hole binary GW150914 opens a new era for probing extreme gravity. Many gravity theories predict the emission of dipole gravitational radiation by binaries. This is excluded to high accuracy in binary pulsars, but entire classes of theories predict this effect predominantly (or only) in binaries involving black holes. Joint observations of GW150914-like systems by aLIGO and eLISA will improve bounds on dipole emission from black-hole binaries by 6 orders of magnitude relative to current constraints, provided that eLISA is not dramatically descoped.
Gravitational wave discovery and characterization of the binary neutron star inspiral GW170817

NASA Astrophysics Data System (ADS)

Littenberg, Tyson; LIGO Scientific Collaboration and Virgo Collaboration

2018-01-01

On August 17, 2017 the Advanced LIGO and Advanced Virgo gravitational-wave detectors observed a binary neutron star inspiral. The source, GW170817, was the closest, loudest, and best localized gravitational-wave observation to date and was part of the spectacular multi-messenger observing campaign including the associated gamma-ray burst, a transient counterpart discovered in the optical, and late-time X-ray and radio emission. This talk will overview the discovery of GW170817 and what has been learned about the source from the gravitational-wave observations.
Gravitational-wave astronomy: delivering on the promises

NASA Astrophysics Data System (ADS)

Schutz, B. F.

2018-05-01

Now that LIGO and Virgo have begun to detect gravitational-wave events with regularity, the field of gravitational-wave astronomy is beginning to realize its promise. Binary black holes and, very recently, binary neutron stars have been observed, and we are already learning much from them. The future, with improved sensitivity, more detectors and detectors like LISA in different frequency bands, has even more promise to open a completely hidden side of the Universe to our exploration. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.
Gravitational-Wave Luminosity of Binary Neutron Stars Mergers

NASA Astrophysics Data System (ADS)

Zappa, Francesco; Bernuzzi, Sebastiano; Radice, David; Perego, Albino; Dietrich, Tim

2018-03-01

We study the gravitational-wave peak luminosity and radiated energy of quasicircular neutron star mergers using a large sample of numerical relativity simulations with different binary parameters and input physics. The peak luminosity for all the binaries can be described in terms of the mass ratio and of the leading-order post-Newtonian tidal parameter solely. The mergers resulting in a prompt collapse to black hole have the largest peak luminosities. However, the largest amount of energy per unit mass is radiated by mergers that produce a hypermassive neutron star or a massive neutron star remnant. We quantify the gravitational-wave luminosity of binary neutron star merger events, and set upper limits on the radiated energy and the remnant angular momentum from these events. We find that there is an empirical universal relation connecting the total gravitational radiation and the angular momentum of the remnant. Our results constrain the final spin of the remnant black hole and also indicate that stable neutron star remnant forms with super-Keplerian angular momentum.

Gravitational-Wave Luminosity of Binary Neutron Stars Mergers.

PubMed

Zappa, Francesco; Bernuzzi, Sebastiano; Radice, David; Perego, Albino; Dietrich, Tim

2018-03-16

We study the gravitational-wave peak luminosity and radiated energy of quasicircular neutron star mergers using a large sample of numerical relativity simulations with different binary parameters and input physics. The peak luminosity for all the binaries can be described in terms of the mass ratio and of the leading-order post-Newtonian tidal parameter solely. The mergers resulting in a prompt collapse to black hole have the largest peak luminosities. However, the largest amount of energy per unit mass is radiated by mergers that produce a hypermassive neutron star or a massive neutron star remnant. We quantify the gravitational-wave luminosity of binary neutron star merger events, and set upper limits on the radiated energy and the remnant angular momentum from these events. We find that there is an empirical universal relation connecting the total gravitational radiation and the angular momentum of the remnant. Our results constrain the final spin of the remnant black hole and also indicate that stable neutron star remnant forms with super-Keplerian angular momentum.
The binary progenitors of short and long GRBs and their gravitational-wave emission

NASA Astrophysics Data System (ADS)

Rueda, J. A.; Ruffini, R.; Rodriguez, J. F.; Muccino, M.; Aimuratov, Y.; Barres de Almeida, U.; Becerra, L.; Bianco, C. L.; Cherubini, C.; Filippi, S.; Kovacevic, M.; Moradi, R.; Pisani, G. B.; Wang, Y.

2018-01-01

We have sub-classified short and long-duration gamma-ray bursts (GRBs) into seven families according to the binary nature of their progenitors. Short GRBs are produced in mergers of neutron-star binaries (NS-NS) or neutron star-black hole binaries (NS-BH). Long GRBs are produced via the induced gravitational collapse (IGC) scenario occurring in a tight binary system composed of a carbon-oxygen core (COcore) and a NS companion. The COcore explodes as type Ic supernova (SN) leading to a hypercritical accretion process onto the NS: if the accretion is sufficiently high the NS reaches the critical mass and collapses forming a BH, otherwise a massive NS is formed. Therefore long GRBs can lead either to NS-BH or to NS-NS binaries depending on the entity of the accretion. We discuss for the above compact-object binaries: 1) the role of the NS structure and the nuclear equation of state; 2) the occurrence rates obtained from X and gamma-rays observations; 3) the predicted annual number of detections by the Advanced LIGO interferometer of their gravitational-wave emission.
GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Afrough, M.; Agarwal, B.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allen, G.; Allocca, A.; Altin, P. A.; Amato, A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Angelova, S. V.; Antier, S.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Atallah, D. V.; Aufmuth, P.; Aulbert, C.; AultONeal, K.; Austin, C.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Bae, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Banagiri, S.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barkett, K.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bawaj, M.; Bayley, J. C.; Bazzan, M.; Bécsy, B.; Beer, C.; Bejger, M.; Belahcene, I.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Bero, J. J.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Biscoveanu, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackman, J.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bode, N.; Boer, M.; Bogaert, G.; Bohe, A.; Bondu, F.; Bonilla, E.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bossie, K.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Bustillo, J. Calderón; Callister, T. A.; Calloni, E.; Camp, J. B.; Canepa, M.; Canizares, P.; Cannon, K. C.; Cao, H.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Carney, M. F.; Diaz, J. Casanueva; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerdá-Durán, P.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chase, E.; Chassande-Mottin, E.; Chatterjee, D.; Cheeseboro, B. D.; Chen, H. Y.; Chen, X.; Chen, Y.; Cheng, H.-P.; Chia, H.; Chincarini, A.; Chiummo, A.; Chmiel, T.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, A. J. K.; Chua, S.; Chung, A. K. W.; Chung, S.; Ciani, G.; Ciolfi, R.; Cirelli, C. E.; Cirone, A.; Clara, F.; Clark, J. A.; Clearwater, P.; Cleva, F.; Cocchieri, C.; Coccia, E.; Cohadon, P.-F.; Cohen, D.; Colla, A.; Collette, C. G.; Cominsky, L. R.; Constancio, M.; Conti, L.; Cooper, S. J.; Corban, P.; Corbitt, T. R.; Cordero-Carrión, I.; Corley, K. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Covas, P. B.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cullen, T. J.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Dálya, G.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davis, D.; Daw, E. J.; Day, B.; De, S.; DeBra, D.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Demos, N.; Denker, T.; Dent, T.; De Pietri, R.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; De Rossi, C.; DeSalvo, R.; de Varona, O.; Devenson, J.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Renzo, F.; Doctor, Z.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dorrington, I.; Douglas, R.; Dovale Álvarez, M.; Downes, T. P.; Drago, M.; Dreissigacker, C.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dupej, P.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Eisenstein, R. A.; Essick, R. C.; Estevez, D.; Etienne, Z. B.; Etzel, T.; Evans, M.; Evans, T. M.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E. J.; Favata, M.; Fays, M.; Fee, C.; Fehrmann, H.; Feicht, J.; Fejer, M. M.; Fernandez-Galiana, A.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Finstad, D.; Fiori, I.; Fiorucci, D.; Fishbach, M.; Fisher, R. P.; Fitz-Axen, M.; Flaminio, R.; Fletcher, M.; Fong, H.; Font, J. A.; Forsyth, P. W. F.; Forsyth, S. S.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fries, E. M.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H.; Gadre, B. U.; Gaebel, S. M.; Gair, J. R.; Gammaitoni, L.; Ganija, M. R.; Gaonkar, S. G.; Garcia-Quiros, C.; Garufi, F.; Gateley, B.; Gaudio, S.; Gaur, G.; Gayathri, V.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, D.; George, J.; Gergely, L.; Germain, V.; Ghonge, S.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glover, L.; Goetz, E.; Goetz, R.; Gomes, S.; Goncharov, B.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Gretarsson, E. M.; Groot, P.; Grote, H.; Grunewald, S.; Gruning, P.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Halim, O.; Hall, B. R.; Hall, E. D.; Hamilton, E. Z.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hannuksela, O. A.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hinderer, T.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Horst, C.; Hough, J.; Houston, E. A.; Howell, E. J.; Hreibi, A.; Hu, Y. M.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Inta, R.; Intini, G.; Isa, H. N.; Isac, J.-M.; Isi, M.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Junker, J.; Kalaghatgi, C. V.; Kalogera, V.; Kamai, B.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katolik, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kawabe, K.; Kéfélian, F.; Keitel, D.; Kemball, A. J.; Kennedy, R.; Kent, C.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J. C.; Kim, K.; Kim, W.; Kim, W. S.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kinley-Hanlon, M.; Kirchhoff, R.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Knowles, T. D.; Koch, P.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Krämer, C.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, P.; Kumar, R.; Kumar, S.; Kuo, L.; Kutynia, A.; Kwang, S.; Lackey, B. D.; Lai, K. H.; Landry, M.; Lang, R. N.; Lange, J.; Lantz, B.; Lanza, R. K.; Lartaux-Vollard, A.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, H. W.; Lee, K.; Lehmann, J.; Lenon, A.; Leonardi, M.; Leroy, N.; Letendre, N.; Levin, Y.; Li, T. G. F.; Linker, S. D.; Littenberg, T. B.; Liu, J.; Lo, R. K. L.; Lockerbie, N. A.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C. O.; Lovelace, G.; Lück, H.; Lumaca, D.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macas, R.; Macfoy, S.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña Hernandez, I.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markakis, C.; Markosyan, A. S.; Markowitz, A.; Maros, E.; Marquina, A.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Mason, K.; Massera, E.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matas, A.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McCuller, L.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McNeill, L.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Mejuto-Villa, E.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, B. B.; Miller, J.; Millhouse, M.; Milovich-Goff, M. C.; Minazzoli, O.; Minenkov, Y.; Ming, J.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moffa, D.; Moggi, A.; Mogushi, K.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Muñiz, E. A.; Muratore, M.; Murray, P. G.; Napier, K.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Neilson, J.; Nelemans, G.; Nelson, T. J. N.; Nery, M.; Neunzert, A.; Nevin, L.; Newport, J. M.; Newton, G.; Ng, K. K. Y.; Nguyen, T. T.; Nichols, D.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Noack, A.; Nocera, F.; Nolting, D.; North, C.; Nuttall, L. K.; Oberling, J.; O'Dea, G. D.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Okada, M. A.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; Ormiston, R.; Ortega, L. F.; O'Shaughnessy, R.; Ossokine, S.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pace, A. E.; Page, J.; Page, M. A.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, Howard; Pan, Huang-Wei; Pang, B.; Pang, P. T. H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Parida, A.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patil, M.; Patricelli, B.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perez, C. J.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pirello, M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Porter, E. K.; Post, A.; Powell, J.; Prasad, J.; Pratt, J. W. W.; Pratten, G.; Predoi, V.; Prestegard, T.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rajbhandari, B.; Rakhmanov, M.; Ramirez, K. E.; Ramos-Buades, A.; Rapagnani, P.; Raymond, V.; Razzano, M.; Read, J.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Ren, W.; Reyes, S. D.; Ricci, F.; Ricker, P. M.; Rieger, S.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romel, C. L.; Romie, J. H.; Rosińska, D.; Ross, M. P.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Rutins, G.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sampson, L. M.; Sanchez, E. J.; Sanchez, L. E.; Sanchis-Gual, N.; Sandberg, V.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Scheel, M.; Scheuer, J.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schulte, B. W.; Schutz, B. F.; Schwalbe, S. G.; Scott, J.; Scott, S. M.; Seidel, E.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D. A.; Shaffer, T. J.; Shah, A. A.; Shahriar, M. S.; Shaner, M. B.; Shao, L.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, L. P.; Singh, A.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, B.; Smith, J. R.; Smith, R. J. E.; Somala, S.; Son, E. J.; Sonnenberg, J. A.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Spencer, A. P.; Srivastava, A. K.; Staats, K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stevenson, S. P.; Stone, R.; Stops, D. J.; Strain, K. A.; Stratta, G.; Strigin, S. E.; Strunk, A.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Suresh, J.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Tait, S. C.; Talbot, C.; Talukder, D.; Tanner, D. B.; Tápai, M.; Taracchini, A.; Tasson, J. D.; Taylor, J. A.; Taylor, R.; Tewari, S. V.; Theeg, T.; Thies, F.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tonelli, M.; Tornasi, Z.; Torres-Forné, A.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trinastic, J.; Tringali, M. C.; Trozzo, L.; Tsang, K. W.; Tse, M.; Tso, R.; Tsukada, L.; Tsuna, D.; Tuyenbayev, D.; Ueno, K.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Varma, V.; Vass, S.; Vasúth, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Venugopalan, G.; Verkindt, D.; Vetrano, F.; Viceré, A.; Viets, A. D.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walet, R.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, J. Z.; Wang, W. H.; Wang, Y. F.; Ward, R. L.; Warner, J.; Was, M.; Watchi, J.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessel, E. K.; Weßels, P.; Westerweck, J.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Whittle, C.; Wilken, D.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Wofford, J.; Wong, K. W. K.; Worden, J.; Wright, J. L.; Wu, D. S.; Wysocki, D. M.; Xiao, S.; Yamamoto, H.; Yancey, C. C.; Yang, L.; Yap, M. J.; Yazback, M.; Yu, Hang; Yu, Haocun; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zelenova, T.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, T.; Zhang, Y.-H.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, S. J.; Zhu, X. J.; Zucker, M. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2018-03-01

The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude ΩGW(f =25 Hz )=1. 8-1.3+2.7×10-9 with 90% confidence, compared with ΩGW(f =25 Hz )=1. 1-0.7+1.2×10-9 from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.
The first gravitational-wave source from the isolated evolution of two stars in the 40-100 solar mass range.

PubMed

Belczynski, Krzysztof; Holz, Daniel E; Bulik, Tomasz; O'Shaughnessy, Richard

2016-06-23

The merger of two massive (about 30 solar masses) black holes has been detected in gravitational waves. This discovery validates recent predictions that massive binary black holes would constitute the first detection. Previous calculations, however, have not sampled the relevant binary-black-hole progenitors--massive, low-metallicity binary stars--with sufficient accuracy nor included sufficiently realistic physics to enable robust predictions to better than several orders of magnitude. Here we report high-precision numerical simulations of the formation of binary black holes via the evolution of isolated binary stars, providing a framework within which to interpret the first gravitational-wave source, GW150914, and to predict the properties of subsequent binary-black-hole gravitational-wave events. Our models imply that these events form in an environment in which the metallicity is less than ten per cent of solar metallicity, and involve stars with initial masses of 40-100 solar masses that interact through mass transfer and a common-envelope phase. These progenitor stars probably formed either about 2 billion years or, with a smaller probability, 11 billion years after the Big Bang. Most binary black holes form without supernova explosions, and their spins are nearly unchanged since birth, but do not have to be parallel. The classical field formation of binary black holes we propose, with low natal kicks (the velocity of the black hole at birth) and restricted common-envelope evolution, produces approximately 40 times more binary-black-holes mergers than do dynamical formation channels involving globular clusters; our predicted detection rate of these mergers is comparable to that from homogeneous evolution channels. Our calculations predict detections of about 1,000 black-hole mergers per year with total masses of 20-80 solar masses once second-generation ground-based gravitational-wave observatories reach full sensitivity.
The first gravitational-wave source from the isolated evolution of two stars in the 40-100 solar mass range

NASA Astrophysics Data System (ADS)

Belczynski, Krzysztof; Holz, Daniel E.; Bulik, Tomasz; O'Shaughnessy, Richard

2016-06-01

The merger of two massive (about 30 solar masses) black holes has been detected in gravitational waves. This discovery validates recent predictions that massive binary black holes would constitute the first detection. Previous calculations, however, have not sampled the relevant binary-black-hole progenitors—massive, low-metallicity binary stars—with sufficient accuracy nor included sufficiently realistic physics to enable robust predictions to better than several orders of magnitude. Here we report high-precision numerical simulations of the formation of binary black holes via the evolution of isolated binary stars, providing a framework within which to interpret the first gravitational-wave source, GW150914, and to predict the properties of subsequent binary-black-hole gravitational-wave events. Our models imply that these events form in an environment in which the metallicity is less than ten per cent of solar metallicity, and involve stars with initial masses of 40-100 solar masses that interact through mass transfer and a common-envelope phase. These progenitor stars probably formed either about 2 billion years or, with a smaller probability, 11 billion years after the Big Bang. Most binary black holes form without supernova explosions, and their spins are nearly unchanged since birth, but do not have to be parallel. The classical field formation of binary black holes we propose, with low natal kicks (the velocity of the black hole at birth) and restricted common-envelope evolution, produces approximately 40 times more binary-black-holes mergers than do dynamical formation channels involving globular clusters; our predicted detection rate of these mergers is comparable to that from homogeneous evolution channels. Our calculations predict detections of about 1,000 black-hole mergers per year with total masses of 20-80 solar masses once second-generation ground-based gravitational-wave observatories reach full sensitivity.
Interferometry in the era of time-domain astronomy

NASA Astrophysics Data System (ADS)

Schaefer, Gail H.; Cassan, Arnaud; Gallenne, Alexandre; Roettenbacher, Rachael M.; Schneider, Jean

2018-04-01

The physical nature of time variable objects is often inferred from photometric light-curves and spectroscopic variations. Long-baseline optical interferometry has the power to resolve the spatial structure of time variable sources directly in order to measure their physical properties and test the physics of the underlying models. Recent interferometric studies of variable objects include measuring the angular expansion and spatial structure during the early stages of novae outbursts, studying the transits and tidal distortions of the components in eclipsing and interacting binaries, measuring the radial pulsations in Cepheid variables, monitoring changes in the circumstellar discs around rapidly rotating massive stars, and imaging starspots. Future applications include measuring the image size and centroid displacements in gravitational microlensing events, and imaging the transits of exoplanets. Ongoing and upcoming photometric surveys will dramatically increase the number of time-variable objects detected each year, providing many potential targets to observe interferometrically. For short-lived transient events, it is critical for interferometric arrays to have the flexibility to respond rapidly to targets of opportunity and optimize the selection of baselines and beam combiners to provide the necessary resolution and sensitivity to resolve the source as its brightness and size change. We discuss the science opportunities made possible by resolving variable sources using long baseline optical interferometry.
Mutual gravitational potential, force, and torque of a homogeneous polyhedron and an extended body: an application to binary asteroids

NASA Astrophysics Data System (ADS)

Shi, Yu; Wang, Yue; Xu, Shijie

2017-11-01

Binary systems are quite common within the populations of near-Earth asteroids, main-belt asteroids, and Kuiper belt asteroids. The dynamics of binary systems, which can be modeled as the full two-body problem, is a fundamental problem for their evolution and the design of relevant space missions. This paper proposes a new shape-based model for the mutual gravitational potential of binary asteroids, differing from prior approaches such as inertia integrals, spherical harmonics, or symmetric trace-free tensors. One asteroid is modeled as a homogeneous polyhedron, while the other is modeled as an extended rigid body with arbitrary mass distribution. Since the potential of the polyhedron is precisely described in a closed form, the mutual gravitational potential can be formulated as a volume integral over the extended body. By using Taylor expansion, the mutual potential is then derived in terms of inertia integrals of the extended body, derivatives of the polyhedron's potential, and the relative location and orientation between the two bodies. The gravitational forces and torques acting on the two bodies described in the body-fixed frame of the polyhedron are derived in the form of a second-order expansion. The gravitational model is then used to simulate the evolution of the binary asteroid (66391) 1999 KW4, and compared with previous results in the literature.
Detecting binary neutron star systems with spin in advanced gravitational-wave detectors

NASA Astrophysics Data System (ADS)

Brown, Duncan A.; Harry, Ian; Lundgren, Andrew; Nitz, Alexander H.

2012-10-01

The detection of gravitational waves from binary neutron stars is a major goal of the gravitational-wave observatories Advanced LIGO and Advanced Virgo. Previous searches for binary neutron stars with LIGO and Virgo neglected the component stars’ angular momentum (spin). We demonstrate that neglecting spin in matched-filter searches causes advanced detectors to lose more than 3% of the possible signal-to-noise ratio for 59% (6%) of sources, assuming that neutron star dimensionless spins, cJ/GM2, are uniformly distributed with magnitudes between 0 and 0.4 (0.05) and that the neutron stars have isotropically distributed spin orientations. We present a new method for constructing template banks for gravitational-wave searches for systems with spin. We present a new metric in a parameter space in which the template placement metric is globally flat. This new method can create template banks of signals with nonzero spins that are (anti-)aligned with the orbital angular momentum. We show that this search loses more than 3% of the maximum signal-to-noise for only 9% (0.2%) of binary neutron star sources with dimensionless spins between 0 and 0.4 (0.05) and isotropic spin orientations. Use of this template bank will prevent selection bias in gravitational-wave searches and allow a more accurate exploration of the distribution of spins in binary neutron stars.
First all-sky search for continuous gravitational waves from unknown sources in binary systems

NASA Astrophysics Data System (ADS)

Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Accadia, T.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Agathos, M.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Andersen, M.; Anderson, R.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Austin, L.; Aylott, B. E.; Babak, S.; Baker, P. T.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauchrowitz, J.; Bauer, Th. S.; Behnke, B.; Bejger, M.; Beker, M. G.; Belczynski, C.; Bell, A. S.; Bell, C.; Bergmann, G.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bloemen, S.; Blom, M.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; Bosi, L.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brückner, F.; Buchman, S.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burman, R.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Calderón Bustillo, J.; Calloni, E.; Camp, J. B.; Campsie, P.; Cannon, K. C.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Carbone, L.; Caride, S.; Castiglia, A.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Celerier, C.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, X.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Chow, J.; Christensen, N.; Chu, Q.; Chua, S. S. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C.; Colombini, M.; Cominsky, L.; Constancio, M.; Conte, A.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corpuz, A.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coughlin, S.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Dal Canton, T.; Damjanic, M.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; Dayanga, T.; Debreczeni, G.; Degallaix, J.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Donath, A.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dossa, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Effler, A.; Eggenstein, H.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Endrőczi, G.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Feroz, F.; Ferrante, I.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gair, J.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, C.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grover, K.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Hammer, D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Hooper, S.; Hopkins, P.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hu, Y.; Huerta, E.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Iyer, B. R.; Izumi, K.; Jacobson, M.; James, E.; Jang, H.; Jaranowski, P.; Ji, Y.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karlen, J.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Keiser, G. M.; Keitel, D.; Kelley, D. B.; Kells, W.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, C.; Kim, K.; Kim, N.; Kim, N. G.; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kline, J.; Koehlenbeck, S.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kremin, A.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, A.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Kwee, P.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J.; Leonardi, M.; Leong, J. R.; Le Roux, A.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B.; Lewis, J.; Li, T. G. F.; Libbrecht, K.; Libson, A.; Lin, A. C.; Littenberg, T. B.; Litvine, V.; Lockerbie, N. A.; Lockett, V.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Lubinski, M. J.; Lück, H.; Luijten, E.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macarthur, J.; Macdonald, E. P.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-Sandoval, F.; Mageswaran, M.; Maglione, C.; Mailand, K.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Manca, G. M.; Mandel, I.; Mandic, V.; Mangano, V.; Mangini, N.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Martinelli, L.; Martynov, D.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McLin, K.; Meacher, D.; Meadors, G. 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J.; Padilla, C.; Pai, A.; Palashov, O.; Palomba, C.; Pan, H.; Pan, Y.; Pankow, C.; Paoletti, F.; Paoletti, R.; Papa, M. A.; Paris, H.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Pedraza, M.; Penn, S.; Perreca, A.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J.; Poggiani, R.; Poteomkin, A.; Powell, J.; Prasad, J.; Premachandra, S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Qin, J.; Quetschke, V.; Quintero, E.; Quiroga, G.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Raja, S.; Rajalakshmi, G.; Rakhmanov, M.; Ramet, C.; Ramirez, K.; Rapagnani, P.; Raymond, V.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Reid, S.; Reitze, D. H.; Rhoades, E.; Ricci, F.; Riles, K.; Robertson, N. A.; Robinet, F.; Rocchi, A.; Rodruck, M.; Rolland, L.; Rollins, J. G.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J. R.; Sannibale, V.; Santiago-Prieto, I.; Saracco, E.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R.; Scheuer, J.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siellez, K.; Siemens, X.; Sigg, D.; Simakov, D.; Singer, A.; Singer, L.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Son, E. J.; Sorazu, B.; Souradeep, T.; Sperandio, L.; Staley, A.; Stebbins, J.; Steinlechner, J.; Steinlechner, S.; Stephens, B. C.; Steplewski, S.; Stevenson, S.; Stone, R.; Stops, D.; Strain, K. A.; Straniero, N.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, R.; ter Braack, A. P. M.; Thirugnanasambandam, M. P.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Toncelli, A.; Tonelli, M.; Torre, O.; Torres, C. V.; Torrie, C. I.; Travasso, F.; Traylor, G.; Tse, M.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Urbanek, K.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Putten, S.; van der Sluys, M. V.; van Heijningen, J.; van Veggel, A. A.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Verma, S. S.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vousden, W. D.; Vyachanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Walker, M.; Wallace, L.; Wang, M.; Wang, X.; Ward, R. L.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Williams, K.; Williams, L.; Williams, R.; Williams, T.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yang, Z.; Yoshida, S.; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, Fan; Zhang, L.; Zhao, C.; Zhu, X. J.; Zucker, M. E.; Zuraw, S.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2014-09-01

We present the first results of an all-sky search for continuous gravitational waves from unknown spinning neutron stars in binary systems using LIGO and Virgo data. Using a specially developed analysis program, the TwoSpect algorithm, the search was carried out on data from the sixth LIGO science run and the second and third Virgo science runs. The search covers a range of frequencies from 20 Hz to 520 Hz, a range of orbital periods from 2 to ˜2,254 h and a frequency- and period-dependent range of frequency modulation depths from 0.277 to 100 mHz. This corresponds to a range of projected semimajor axes of the orbit from ˜0.6×10-3 ls to ˜6,500 ls assuming the orbit of the binary is circular. While no plausible candidate gravitational wave events survive the pipeline, upper limits are set on the analyzed data. The most sensitive 95% confidence upper limit obtained on gravitational wave strain is 2.3×10-24 at 217 Hz, assuming the source waves are circularly polarized. Although this search has been optimized for circular binary orbits, the upper limits obtained remain valid for orbital eccentricities as large as 0.9. In addition, upper limits are placed on continuous gravitational wave emission from the low-mass x-ray binary Scorpius X-1 between 20 Hz and 57.25 Hz.
A Bayesian approach to multi-messenger astronomy: identification of gravitational-wave host galaxies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, XiLong; Messenger, Christopher; Heng, Ik Siong

We present a general framework for incorporating astrophysical information into Bayesian parameter estimation techniques used by gravitational wave data analysis to facilitate multi-messenger astronomy. Since the progenitors of transient gravitational wave events, such as compact binary coalescences, are likely to be associated with a host galaxy, improvements to the source sky location estimates through the use of host galaxy information are explored. To demonstrate how host galaxy properties can be included, we simulate a population of compact binary coalescences and show that for ∼8.5% of simulations within 200 Mpc, the top 10 most likely galaxies account for a ∼50% ofmore » the total probability of hosting a gravitational wave source. The true gravitational wave source host galaxy is in the top 10 galaxy candidates ∼10% of the time. Furthermore, we show that by including host galaxy information, a better estimate of the inclination angle of a compact binary gravitational wave source can be obtained. We also demonstrate the flexibility of our method by incorporating the use of either the B or K band into our analysis.« less
Upper Limits on the Stochastic Gravitational-Wave Background from Advanced LIGO's First Observing Run

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Beer, C.; Bejger, M.; Belahcene, I.; Belgin, M.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Biscoveanu, A. S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackman, J.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Boer, M.; Bogaert, G.; Bohe, A.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T. A.; Calloni, E.; Camp, J. B.; Campbell, W.; Canepa, M.; Cannon, K. C.; Cao, H.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, H.-P.; Chincarini, A.; Chiummo, A.; Chmiel, T.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, A. J. K.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Cocchieri, C.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conti, L.; Cooper, S. J.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, E.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Covas, P. B.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cullen, T. J.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Davis, D.; Daw, E. J.; Day, B.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devenson, J.; Devine, R. C.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Doctor, Z.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dorrington, I.; Douglas, R.; Dovale Álvarez, M.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Essick, R. C.; Etienne, Z.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E. J.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fernández Galiana, A.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fong, H.; Forsyth, S. S.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fries, E. M.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H.; Gadre, B. U.; Gaebel, S. M.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gayathri, V.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghonge, S.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Junker, J.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kéfélian, F.; Keitel, D.; Kelley, D. B.; Kennedy, R.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J. C.; Kim, Whansun; Kim, W.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kirchhoff, R.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koch, P.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Krämer, C.; Kringel, V.; Królak, A.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lang, R. N.; Lange, J.; Lantz, B.; Lanza, R. K.; Lartaux-Vollard, A.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lehmann, J.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Liu, J.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lovelace, G.; Lück, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macfoy, S.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matas, A.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGrath, C.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Muniz, E. A. M.; Murray, P. G.; Mytidis, A.; Napier, K.; Nardecchia, I.; Naticchioni, L.; Nelemans, G.; Nelson, T. J. 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J.; Venkateswara, K.; Venugopalan, G.; Verkindt, D.; Vetrano, F.; Viceré, A.; Viets, A. D.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Watchi, J.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Whittle, C.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, Hang; Yu, Haocun; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, T.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, S. J.; Zhu, X. J.; Zucker, M. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2017-03-01

A wide variety of astrophysical and cosmological sources are expected to contribute to a stochastic gravitational-wave background. Following the observations of GW150914 and GW151226, the rate and mass of coalescing binary black holes appear to be greater than many previous expectations. As a result, the stochastic background from unresolved compact binary coalescences is expected to be particularly loud. We perform a search for the isotropic stochastic gravitational-wave background using data from Advanced Laser Interferometer Gravitational Wave Observatory's (aLIGO) first observing run. The data display no evidence of a stochastic gravitational-wave signal. We constrain the dimensionless energy density of gravitational waves to be Ω0<1.7 ×10-7 with 95% confidence, assuming a flat energy density spectrum in the most sensitive part of the LIGO band (20-86 Hz). This is a factor of ˜33 times more sensitive than previous measurements. We also constrain arbitrary power-law spectra. Finally, we investigate the implications of this search for the background of binary black holes using an astrophysical model for the background.
Upper Limits on the Stochastic Gravitational-Wave Background from Advanced LIGO's First Observing Run.

PubMed

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McIntyre, G; McIver, J; McManus, D J; McRae, T; McWilliams, S T; Meacher, D; Meadors, G D; Meidam, J; Melatos, A; Mendell, G; Mendoza-Gandara, D; Mercer, R A; Merilh, E L; Merzougui, M; Meshkov, S; Messenger, C; Messick, C; Metzdorff, R; Meyers, P M; Mezzani, F; Miao, H; Michel, C; Middleton, H; Mikhailov, E E; Milano, L; Miller, A L; Miller, A; Miller, B B; Miller, J; Millhouse, M; Minenkov, Y; Ming, J; Mirshekari, S; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moggi, A; Mohan, M; Mohapatra, S R P; Montani, M; Moore, B C; Moore, C J; Moraru, D; Moreno, G; Morriss, S R; Mours, B; Mow-Lowry, C M; Mueller, G; Muir, A W; Mukherjee, Arunava; Mukherjee, D; Mukherjee, S; Mukund, N; Mullavey, A; Munch, J; Muniz, E A M; Murray, P G; Mytidis, A; Napier, K; Nardecchia, I; Naticchioni, L; Nelemans, G; Nelson, T J N; Neri, M; Nery, M; Neunzert, A; Newport, J M; Newton, G; Nguyen, T T; Nielsen, A B; Nissanke, S; Nitz, A; Noack, A; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Oberling, J; Ochsner, E; Oelker, E; Ogin, G H; Oh, J J; Oh, S H; Ohme, F; Oliver, M; Oppermann, P; Oram, Richard J; O'Reilly, B; O'Shaughnessy, R; Ottaway, D J; Overmier, H; Owen, B J; Pace, A E; Page, J; Pai, A; Pai, S A; Palamos, J R; Palashov, O; Palomba, C; Pal-Singh, A; Pan, H; Pankow, C; Pannarale, F; Pant, B C; Paoletti, F; Paoli, A; Papa, M A; Paris, H R; Parker, W; Pascucci, D; Pasqualetti, A; Passaquieti, R; Passuello, D; Patricelli, B; Pearlstone, B L; Pedraza, M; Pedurand, R; Pekowsky, L; Pele, A; Penn, S; Perez, C J; Perreca, A; Perri, L M; Pfeiffer, H P; Phelps, M; Piccinni, O J; Pichot, M; Piergiovanni, F; Pierro, V; Pillant, G; Pinard, L; Pinto, I M; Pitkin, M; Poe, M; Poggiani, R; Popolizio, P; Post, A; Powell, J; Prasad, J; Pratt, J W W; Predoi, V; Prestegard, T; Prijatelj, M; Principe, M; Privitera, S; Prodi, G A; Prokhorov, L G; Puncken, O; Punturo, M; Puppo, P; Pürrer, M; Qi, H; Qin, J; Qiu, S; Quetschke, V; Quintero, E A; Quitzow-James, R; Raab, F J; Rabeling, D S; Radkins, H; Raffai, P; Raja, S; Rajan, C; Rakhmanov, M; Rapagnani, P; Raymond, V; Razzano, M; Re, V; Read, J; Regimbau, T; Rei, L; Reid, S; Reitze, D H; Rew, H; Reyes, S D; Rhoades, E; Ricci, F; Riles, K; Rizzo, M; Robertson, N A; Robie, R; Robinet, F; Rocchi, A; Rolland, L; Rollins, J G; Roma, V J; Romano, J D; Romano, R; Romie, J H; Rosińska, D; Rowan, S; Rüdiger, A; Ruggi, P; Ryan, K; Sachdev, S; Sadecki, T; Sadeghian, L; Sakellariadou, M; Salconi, L; Saleem, M; Salemi, F; Samajdar, A; Sammut, L; Sampson, L M; Sanchez, E J; Sandberg, V; Sanders, J R; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Sauter, O; Savage, R L; Sawadsky, A; Schale, P; Scheuer, J; Schlassa, S; Schmidt, E; Schmidt, J; Schmidt, P; Schnabel, R; Schofield, R M S; Schönbeck, A; Schreiber, E; Schuette, D; Schutz, B F; Schwalbe, S G; Scott, J; Scott, S M; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Setyawati, Y; Shaddock, D A; Shaffer, T J; Shahriar, M S; Shapiro, B; Shawhan, P; Sheperd, A; Shoemaker, D H; Shoemaker, D M; Siellez, K; Siemens, X; Sieniawska, M; Sigg, D; Silva, A D; Singer, A; Singer, L P; Singh, A; Singh, R; Singhal, A; Sintes, A M; Slagmolen, B J J; Smith, B; Smith, J R; Smith, R J E; Son, E J; Sorazu, B; Sorrentino, F; Souradeep, T; Spencer, A P; Srivastava, A K; Staley, A; Steinke, M; Steinlechner, J; Steinlechner, S; Steinmeyer, D; Stephens, B C; Stevenson, S P; Stone, R; Strain, K A; Straniero, N; Stratta, G; Strigin, S E; Sturani, R; Stuver, A L; Summerscales, T Z; Sun, L; Sunil, S; Sutton, P J; Swinkels, B L; Szczepańczyk, M J; Tacca, M; Talukder, D; Tanner, D B; Tao, D; Tápai, M; Taracchini, A; Taylor, R; Theeg, T; Thomas, E G; Thomas, M; Thomas, P; Thorne, K A; Thrane, E; Tippens, T; Tiwari, S; Tiwari, V; Tokmakov, K V; Toland, K; Tomlinson, C; Tonelli, M; Tornasi, Z; Torrie, C I; Töyrä, D; Travasso, F; Traylor, G; Trifirò, D; Trinastic, J; Tringali, M C; Trozzo, L; Tse, M; Tso, R; Turconi, M; Tuyenbayev, D; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; van Bakel, N; van Beuzekom, M; van den Brand, J F J; Van Den Broeck, C; Vander-Hyde, D C; van der Schaaf, L; van Heijningen, J V; van Veggel, A A; Vardaro, M; Varma, V; Vass, S; Vasúth, M; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Venugopalan, G; Verkindt, D; Vetrano, F; Viceré, A; Viets, A D; Vinciguerra, S; Vine, D J; Vinet, J-Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Voss, D V; Vousden, W D; Vyatchanin, S P; Wade, A R; Wade, L E; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, G; Wang, H; Wang, M; Wang, Y; Ward, R L; Warner, J; Was, M; Watchi, J; Weaver, B; Wei, L-W; Weinert, M; Weinstein, A J; Weiss, R; Wen, L; Weßels, P; Westphal, T; Wette, K; Whelan, J T; Whiting, B F; Whittle, C; Williams, D; Williams, R D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M H; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Woehler, J; Worden, J; Wright, J L; Wu, D S; Wu, G; Yam, W; Yamamoto, H; Yancey, C C; Yap, M J; Yu, Hang; Yu, Haocun; Yvert, M; Zadrożny, A; Zangrando, L; Zanolin, M; Zendri, J-P; Zevin, M; Zhang, L; Zhang, M; Zhang, T; Zhang, Y; Zhao, C; Zhou, M; Zhou, Z; Zhu, S J; Zhu, X J; Zucker, M E; Zweizig, J

2017-03-24

A wide variety of astrophysical and cosmological sources are expected to contribute to a stochastic gravitational-wave background. Following the observations of GW150914 and GW151226, the rate and mass of coalescing binary black holes appear to be greater than many previous expectations. As a result, the stochastic background from unresolved compact binary coalescences is expected to be particularly loud. We perform a search for the isotropic stochastic gravitational-wave background using data from Advanced Laser Interferometer Gravitational Wave Observatory's (aLIGO) first observing run. The data display no evidence of a stochastic gravitational-wave signal. We constrain the dimensionless energy density of gravitational waves to be Ω_{0}<1.7×10^{-7} with 95% confidence, assuming a flat energy density spectrum in the most sensitive part of the LIGO band (20-86 Hz). This is a factor of ∼33 times more sensitive than previous measurements. We also constrain arbitrary power-law spectra. Finally, we investigate the implications of this search for the background of binary black holes using an astrophysical model for the background.
Numerical relativity simulations of precessing binary neutron star mergers

NASA Astrophysics Data System (ADS)

Dietrich, Tim; Bernuzzi, Sebastiano; Brügmann, Bernd; Ujevic, Maximiliano; Tichy, Wolfgang

2018-03-01

We present the first set of numerical relativity simulations of binary neutron mergers that include spin precession effects and are evolved with multiple resolutions. Our simulations employ consistent initial data in general relativity with different spin configurations and dimensionless spin magnitudes ˜0.1 . They start at a gravitational-wave frequency of ˜392 Hz and cover more than 1 precession period and about 15 orbits up to merger. We discuss the spin precession dynamics by analyzing coordinate trajectories, quasilocal spin measurements, and energetics, by comparing spin aligned, antialigned, and irrotational configurations. Gravitational waveforms from different spin configuration are compared by calculating the mismatch between pairs of waveforms in the late inspiral. We find that precession effects are not distinguishable from nonprecessing configurations with aligned spins for approximately face-on binaries, while the latter are distinguishable from nonspinning configurations. Spin precession effects are instead clearly visible for approximately edge-on binaries. For the parameters considered here, precession does not significantly affect the characteristic postmerger gravitational-wave frequencies nor the mass ejection. Our results pave the way for the modeling of spin precession effects in the gravitational waveform from binary neutron star events.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Sánchez-Salcedo, F. J.; Chametla, Raul O., E-mail: jsanchez@astro.unam.mx

Using time-dependent linear theory, we investigate the morphology of the gravitational wake induced by a binary, whose center of mass moves at velocity V{sub cm} against a uniform background of gas. For simplicity, we assume that the components of the binary are on circular orbits about their common center of mass. The consequences of dynamical friction is twofold. First, gas dynamical friction may drag the center of mass of the binary and cause the binary to migrate. Second, drag forces also induce a braking torque, which causes the orbits of the components of the binary to shrink. We compute themore » drag forces acting on one component of the binary due to the gravitational interaction with its own wake. We show that the dynamical friction force responsible for decelerating the center of mass of the binary is smaller than it is in the point-mass case because of the loss of gravitational focusing. We show that the braking internal torque depends on the Mach numbers of each binary component about their center of mass, and also on the Mach number of the center of mass of the binary. In general, the internal torque decreases with increasing the velocity of the binary relative to the ambient gas cloud. However, this is not always the case. We also mention the relevance of our results to the period distribution of binaries.« less
Spin memory effect for compact binaries in the post-Newtonian approximation

NASA Astrophysics Data System (ADS)

Nichols, David A.

2017-04-01

The spin memory effect is a recently predicted relativistic phenomenon in asymptotically flat spacetimes that become nonradiative infinitely far in the past and future. Between these early and late times, the magnetic-parity part of the time integral of the gravitational-wave strain can undergo a nonzero change; this difference is the spin memory effect. Families of freely falling observers around an isolated source can measure this effect, in principle, and fluxes of angular momentum per unit solid angle (or changes in superspin charges) generate the effect. The spin memory effect had not been computed explicitly for astrophysical sources of gravitational waves, such as compact binaries. In this paper, we compute the spin memory in terms of a set of radiative multipole moments of the gravitational-wave strain. The result of this calculation allows us to establish the following results about the spin memory: (i) We find that the accumulation of the spin memory behaves in a qualitatively different way from that of the displacement memory effect for nonspinning, quasicircular compact binaries in the post-Newtonian approximation: the spin memory undergoes a large secular growth over the duration of the inspiral, whereas for the displacement effect this increase is small. (ii) The rate at which the spin memory grows is equivalent to a nonlinear, but nonoscillatory and nonhereditary effect in the gravitational waveform that had been previously calculated for nonspinning, quasicircular compact binaries. (iii) This rate of buildup of the spin memory could potentially be detected by future gravitational-wave detectors by carefully combining the measured waveforms from hundreds of gravitational-wave detections of compact binaries.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Sajadian, Sedighe; Hundertmark, Markus, E-mail: s.sajadian@cc.iut.ac.ir

A close-in giant planetary (CGP) system has a net polarization signal whose value varies depending on the orbital phase of the planet. This polarization signal is either caused by the stellar occultation or by reflected starlight from the surface of the orbiting planet. When the CGP system is located in the Galactic bulge, its polarization signal becomes too weak to be measured directly. One method for detecting and characterizing these weak polarization signatures due to distant CGP systems is gravitational microlensing. In this work, we focus on potential polarimetric observations of highly magnified microlensing events of CGP systems. When themore » lens is passing directly in front of the source star with its planetary companion, the polarimetric signature caused by the transiting planet is magnified. As a result, some distinct features in the polarimetry and light curves are produced. In the same way, microlensing amplifies the reflection-induced polarization signal. While the planet-induced perturbations are magnified whenever these polarimetric or photometric deviations vanish for a moment, the corresponding magnification factor of the polarization component(s) is related to the planet itself. Finding these exact times in the planet-induced perturbations helps us to characterize the planet. In order to evaluate the observability of such systems through polarimetric or photometric observations of high-magnification microlensing events, we simulate these events by considering confirmed CGP systems as their source stars and conclude that the efficiency for detecting the planet-induced signal with the state-of-the-art polarimetric instrument (FORS2/VLT) is less than 0.1%. Consequently, these planet-induced polarimetry perturbations can likely be detected under favorable conditions by the high-resolution and short-cadence polarimeters of the next generation.« less
Optimal survey strategies and predicted planet yields for the Korean microlensing telescope network

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, Calen B.; Gaudi, B. Scott; Skowron, Jan

2014-10-10

The Korean Microlensing Telescope Network (KMTNet) will consist of three 1.6 m telescopes each with a 4 deg{sup 2} field of view (FoV) and will be dedicated to monitoring the Galactic Bulge to detect exoplanets via gravitational microlensing. KMTNet's combination of aperture size, FoV, cadence, and longitudinal coverage will provide a unique opportunity to probe exoplanet demographics in an unbiased way. Here we present simulations that optimize the observing strategy for and predict the planetary yields of KMTNet. We find preferences for four target fields located in the central Bulge and an exposure time of t {sub exp} = 120more » s, leading to the detection of ∼2200 microlensing events per year. We estimate the planet detection rates for planets with mass and separation across the ranges 0.1 ≤ M{sub p} /M {sub ⊕} ≤ 1000 and 0.4 ≤ a/AU ≤ 16, respectively. Normalizing these rates to the cool-planet mass function of Cassan et al., we predict KMTNet will be approximately uniformly sensitive to planets with mass 5 ≤ M{sub p} /M {sub ⊕} ≤ 1000 and will detect ∼20 planets per year per dex in mass across that range. For lower-mass planets with mass 0.1 ≤ M{sub p} /M {sub ⊕} < 5, we predict KMTNet will detect ∼10 planets per year. We also compute the yields KMTNet will obtain for free-floating planets (FFPs) and predict KMTNet will detect ∼1 Earth-mass FFP per year, assuming an underlying population of one such planet per star in the Galaxy. Lastly, we investigate the dependence of these detection rates on the number of observatories, the photometric precision limit, and optimistic assumptions regarding seeing, throughput, and flux measurement uncertainties.« less
Approximation methods in gravitational-radiation theory

NASA Technical Reports Server (NTRS)

Will, C. M.

1986-01-01

The observation of gravitational-radiation damping in the binary pulsar PSR 1913 + 16 and the ongoing experimental search for gravitational waves of extraterrestrial origin have made the theory of gravitational radiation an active branch of classical general relativity. In calculations of gravitational radiation, approximation methods play a crucial role. Recent developments are summarized in two areas in which approximations are important: (a) the quadrupole approxiamtion, which determines the energy flux and the radiation reaction forces in weak-field, slow-motion, source-within-the-near-zone systems such as the binary pulsar; and (b) the normal modes of oscillation of black holes, where the Wentzel-Kramers-Brillouin approximation gives accurate estimates of the complex frequencies of the modes.
Gravitational-wave astronomy: delivering on the promises.

PubMed

Schutz, B F

2018-05-28

Now that LIGO and Virgo have begun to detect gravitational-wave events with regularity, the field of gravitational-wave astronomy is beginning to realize its promise. Binary black holes and, very recently, binary neutron stars have been observed, and we are already learning much from them. The future, with improved sensitivity, more detectors and detectors like LISA in different frequency bands, has even more promise to open a completely hidden side of the Universe to our exploration.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).
Black hole binaries in galactic nuclei and gravitational wave sources

NASA Astrophysics Data System (ADS)

Hong, Jongsuk; Lee, Hyung Mok

2015-03-01

Stellar black hole (BH) binaries are one of the most promising gravitational wave (GW) sources for GW detection by the ground-based detectors. Nuclear star clusters (NCs) located at the centre of galaxies are known to harbour massive black holes (MBHs) and to be bounded by a gravitational potential by other galactic components such as the galactic bulge. Such an environment of NCs provides a favourable conditions for the BH-BH binary formation by the gravitational radiation capture due to the high BH number density and velocity dispersion. We carried out detailed numerical study of the formation of BH binaries in the NCs using a series of N-body simulations for equal-mass cases. There is no mass segregation introduced. We have derived scaling relations of the binary formation rate with the velocity dispersion of the stellar system beyond the radius of influence and made estimates of the rate of formation of BH binaries per unit comoving volume and thus expected detection rate by integrating the binary formation rate over galaxy population within the detection distance of the advanced detectors. We find that the overall formation rates for BH-BH binaries per NC is ˜10-10 yr-1 for the Milky Way-like galaxies and weakly dependent on the mass of MBH as Γ ∝ M_MBH^{3/28}. We estimate the detection rate of 0.02-14 yr-1 for advanced LIGO/Virgo considering several factors such as the dynamical evolution of NCs, the variance of the number density of stars and the mass range of MBH giving uncertainties.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruiter, Ashley J.; Belczynski, Krzysztof; Benacquista, Matthew

Double white dwarfs (WDs) are expected to be a source of confusion-limited noise for the future gravitational wave observatory LISA. In a specific frequency range, this 'foreground noise' is predicted to rise above the instrumental noise and hinder the detection of other types of signals, e.g., gravitational waves arising from stellar-mass objects inspiraling into massive black holes. In many previous studies, only detached populations of compact object binaries have been considered in estimating the LISA gravitational wave foreground signal. Here, we investigate the influence of compact object detached and Roche-Lobe overflow (RLOF) Galactic binaries on the shape and strength ofmore » the LISA signal. Since >99% of remnant binaries that have orbital periods within the LISA sensitivity range are WD binaries, we consider only these binaries when calculating the LISA signal. We find that the contribution of RLOF binaries to the foreground noise is negligible at low frequencies, but becomes significant at higher frequencies, pushing the frequency at which the foreground noise drops below the instrumental noise to >6 mHz. We find that it is important to consider the population of mass-transferring binaries in order to obtain an accurate assessment of the foreground noise on the LISA data stream. However, we estimate that there still exists a sizeable number ({approx}11,300) of Galactic double WD binaries that will have a signal-to-noise ratio >5, and thus will be potentially resolvable with LISA. We present the LISA gravitational wave signal from the Galactic population of WD binaries, show the most important formation channels contributing to the LISA disk and bulge populations, and discuss the implications of these new findings.« less
Low-Frequency Gravitational Radiation from Coalescing Massive Black Hole Binaries in Hierarchical Cosmologies

NASA Astrophysics Data System (ADS)

Sesana, Alberto; Haardt, Francesco; Madau, Piero; Volonteri, Marta

2004-08-01

We compute the expected low-frequency gravitational wave signal from coalescing massive black hole (MBH) binaries at the center of galaxies in a hierarchical structure formation scenario in which seed holes of intermediate mass form far up in the dark halo ``merger tree.'' The merger history of dark matter halos and associated MBHs is followed via cosmological Monte Carlo realizations of the merger hierarchy from redshift z=20 to the present in a ΛCDM cosmology. MBHs get incorporated through halo mergers into larger and larger structures, sink to the center because of dynamical friction against the dark matter background, accrete cold material in the merger remnant, and form MBH binary systems. Stellar dynamical (three-body) interactions cause the hardening of the binary at large separations, while gravitational wave emission takes over at small radii and leads to the final coalescence of the pair. A simple scheme is applied in which the ``loss cone'' is constantly refilled and a constant stellar density core forms because of the ejection of stars by the shrinking binary. The integrated emission from inspiraling MBH binaries at all redshifts is computed in the quadrupole approximation and results in a gravitational wave background (GWB) with a well-defined shape that reflects the different mechanisms driving the late orbital evolution. The characteristic strain spectrum has the standard hc(f)~f-2/3 behavior only in the range f=10-9to10-6 Hz. At lower frequencies the orbital decay of MBH binaries is driven by the ejection of background stars (``gravitational slingshot''), and the strain amplitude increases with frequency, hc(f)~f. In this range the GWB is dominated by 109-1010 Msolar MBH pairs coalescing at 0<~z<~2. At higher frequencies, f>10-6Hz, the strain amplitude, as steep as hc(f)~f-1.3, is shaped by the convolution of last stable circular orbit emission by lighter binaries (102-107 Msolar) populating galaxy halos at all redshifts. We discuss the observability of inspiraling MBH binaries by a low-frequency gravitational wave experiment such as the planned Laser Interferometer Space Antenna (LISA). Over a 3 yr observing period LISA should resolve this GWB into discrete sources, detecting ~60 (~250) individual events above an S/N=5 (S/N=1) confidence level.
A new direction for dark matter research: intermediate-mass compact halo objects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapline, George F.; Frampton, Paul H., E-mail: george.chapline@gmail.com, E-mail: paul.h.frampton@gmail.com

2016-11-01

The failure to find evidence for elementary particles that could serve as the constituents of dark matter brings to mind suggestions that dark matter might consist of massive compact objects (MACHOs). In particular, it has recently been argued that MACHOs with masses > 15 M {sub ⊙} may have been prolifically produced at the onset of the big bang. Although a variety of astrophysical signatures for primordial MACHOs with masses in this range have been discussed in the literature, we favor a strategy that uses the potential for magnification of stars outside our galaxy due to gravitational microlensing of thesemore » stars by MACHOs in the halo of our galaxy. We point out that the effect of the motion of the Earth on the shape of the micro-lensing brightening curves provides a promising approach to testing over the course of next several years the hypothesis that dark matter consists of massive compact objects.« less
Fast computation of quadrupole and hexadecapole approximations in microlensing with a single point-source evaluation

NASA Astrophysics Data System (ADS)

Cassan, Arnaud

2017-07-01

The exoplanet detection rate from gravitational microlensing has grown significantly in recent years thanks to a great enhancement of resources and improved observational strategy. Current observatories include ground-based wide-field and/or robotic world-wide networks of telescopes, as well as space-based observatories such as satellites Spitzer or Kepler/K2. This results in a large quantity of data to be processed and analysed, which is a challenge for modelling codes because of the complexity of the parameter space to be explored and the intensive computations required to evaluate the models. In this work, I present a method that allows to compute the quadrupole and hexadecapole approximations of the finite-source magnification with more efficiency than previously available codes, with routines about six times and four times faster, respectively. The quadrupole takes just about twice the time of a point-source evaluation, which advocates for generalizing its use to large portions of the light curves. The corresponding routines are available as open-source python codes.
Opto-mechanical analysis of nonlinear elastomer membrane deformation under hydraulic pressure for variable-focus liquid-filled microlenses.

PubMed

Choi, Seung Tae; Son, Byeong Soo; Seo, Gye Won; Park, Si-Young; Lee, Kyung-Sick

2014-03-10

Nonlinear large deformation of a transparent elastomer membrane under hydraulic pressure was analyzed to investigate its optical performance for a variable-focus liquid-filled membrane microlens. In most membrane microlenses, actuators control the hydraulic pressure of optical fluid so that the elastomer membrane together with the internal optical fluid changes its shape, which alters the light path of the microlens to adapt its optical power. A fluid-structure interaction simulation was performed to estimate the transient behavior of the microlens under the operation of electroactive polymer actuators, demonstrating that the viscosity of the optical fluid successfully stabilizes the fluctuations within a fairly short period of time during dynamic operations. Axisymmetric nonlinear plate theory was used to calculate the deformation profile of the membrane under hydrostatic pressure, with which optical characteristics of the membrane microlens were estimated. The effects of gravitation and viscoelastic behavior of the elastomer membrane on the optical performance of the membrane microlens were also evaluated with finite element analysis.
Baryonic Dark Matter: The Results from Microlensing Surveys

NASA Astrophysics Data System (ADS)

Alcock, Charles; Allsman, Robyn A.; Alves, David; Axelrod, Tim S.; Becker, Andrew C.; Bennett, David; Cook, Kem H.; Drake, Andrew J.; Freeman, Ken C.; Griest, Kim; Lehner, Matt; Marshall, Stuart; Minniti, Dante; Peterson, Bruce; Pratt, Mark; Quinn, Peter; Rodgers, Alex; Stubbs, Chris; Sutherland, Will; Tomaney, Austin; Vandehei, Thor; Welch, Doug L.

Baryonic material can exist in several dark forms: ``planets," brown dwarfs, very old degenerate dwarf stars, and neutron stars. (Black holes are frequently added to this list, even though a black hole has no baryon number.) These objects, most of which emit some light but at levels below present day detection thresholds, are collectively known as Machos. Several groups have exploited the gravitational microlens signature to search for Machos in the dark halo of the Milky Way. Over 200 microlensing events have been reported (most by the MACHO Project, which uses the Great Melbourne Telescope near this conference site), of which about 20 are toward the Magellanic Clouds. The most straightforward interpretation of the results is that Machos make up between 20% and 100% of the dark matter in the halo, and that these objects weigh about 0.5 msun. Objects of substellar mass do not comprise much of the dark matter. Many alternative interpretations of these results have been proposed. We will discuss strategies for resolving the differences among these competing explanations.
First Higher-Multipole Model of Gravitational Waves from Spinning and Coalescing Black-Hole Binaries

NASA Astrophysics Data System (ADS)

London, Lionel; Khan, Sebastian; Fauchon-Jones, Edward; García, Cecilio; Hannam, Mark; Husa, Sascha; Jiménez-Forteza, Xisco; Kalaghatgi, Chinmay; Ohme, Frank; Pannarale, Francesco

2018-04-01

Gravitational-wave observations of binary black holes currently rely on theoretical models that predict the dominant multipoles (ℓ=2 ,|m |=2 ) of the radiation during inspiral, merger, and ringdown. We introduce a simple method to include the subdominant multipoles to binary black hole gravitational waveforms, given a frequency-domain model for the dominant multipoles. The amplitude and phase of the original model are appropriately stretched and rescaled using post-Newtonian results (for the inspiral), perturbation theory (for the ringdown), and a smooth transition between the two. No additional tuning to numerical-relativity simulations is required. We apply a variant of this method to the nonprecessing PhenomD model. The result, PhenomHM, constitutes the first higher-multipole model of spinning and coalescing black-hole binaries, and currently includes the (ℓ,|m |)=(2 ,2 ),(3 ,3 ),(4 ,4 ),(2 ,1 ),(3 ,2 ),(4 ,3 ) radiative moments. Comparisons with numerical-relativity waveforms demonstrate that PhenomHM is more accurate than dominant-multipole-only models for all binary configurations, and typically improves the measurement of binary properties.
First Higher-Multipole Model of Gravitational Waves from Spinning and Coalescing Black-Hole Binaries.

PubMed

London, Lionel; Khan, Sebastian; Fauchon-Jones, Edward; García, Cecilio; Hannam, Mark; Husa, Sascha; Jiménez-Forteza, Xisco; Kalaghatgi, Chinmay; Ohme, Frank; Pannarale, Francesco

2018-04-20

Gravitational-wave observations of binary black holes currently rely on theoretical models that predict the dominant multipoles (ℓ=2,|m|=2) of the radiation during inspiral, merger, and ringdown. We introduce a simple method to include the subdominant multipoles to binary black hole gravitational waveforms, given a frequency-domain model for the dominant multipoles. The amplitude and phase of the original model are appropriately stretched and rescaled using post-Newtonian results (for the inspiral), perturbation theory (for the ringdown), and a smooth transition between the two. No additional tuning to numerical-relativity simulations is required. We apply a variant of this method to the nonprecessing PhenomD model. The result, PhenomHM, constitutes the first higher-multipole model of spinning and coalescing black-hole binaries, and currently includes the (ℓ,|m|)=(2,2),(3,3),(4,4),(2,1),(3,2),(4,3) radiative moments. Comparisons with numerical-relativity waveforms demonstrate that PhenomHM is more accurate than dominant-multipole-only models for all binary configurations, and typically improves the measurement of binary properties.
Search for Open binaries in the Southern Celestial Hemisphere using SPM4

NASA Astrophysics Data System (ADS)

Dávila, E.; Vieira, K.; Rosales, K.

2018-01-01

Open binaries' weak gravitational binding makes them vulnerable to any perturbation, turning them into excellent probes of the gravitational field where they are located. Currently there are only a few hundreds known or suspected open binaries, therefore a search for more of these systems is highly encouraging by looking for pairs of stars with common proper motions in an extensive, deep, and high quality astrometric catalog such as the SPM4 (Girard et al. 2011).
GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences.

PubMed

Abbott, B P; Abbott, R; Abbott, T D; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V B; Affeldt, C; Afrough, M; Agarwal, B; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Aiello, L; Ain, A; Ajith, P; Allen, B; Allen, G; Allocca, A; Altin, P A; Amato, A; Ananyeva, A; Anderson, S B; Anderson, W G; Angelova, S V; Antier, S; Appert, S; Arai, K; Araya, M C; Areeda, J S; Arnaud, N; Arun, K G; Ascenzi, S; Ashton, G; Ast, M; Aston, S M; Astone, P; Atallah, D V; Aufmuth, P; Aulbert, C; AultONeal, K; Austin, C; Avila-Alvarez, A; Babak, S; Bacon, P; Bader, M K M; Bae, S; Baker, P T; Baldaccini, F; Ballardin, G; Ballmer, S W; Banagiri, S; Barayoga, J C; Barclay, S E; Barish, B C; Barker, D; Barkett, K; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barta, D; Bartlett, J; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Bawaj, M; Bayley, J C; Bazzan, M; Bécsy, B; Beer, C; Bejger, M; Belahcene, I; Bell, A S; Berger, B K; Bergmann, G; Bero, J J; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Billman, C R; Birch, J; Birney, R; Birnholtz, O; Biscans, S; Biscoveanu, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blackman, J; Blair, C D; Blair, D G; Blair, R M; Bloemen, S; Bock, O; Bode, N; Boer, M; Bogaert, G; Bohe, A; Bondu, F; Bonilla, E; Bonnand, R; Boom, B A; Bork, R; Boschi, V; Bose, S; Bossie, K; Bouffanais, Y; Bozzi, A; Bradaschia, C; Brady, P R; Branchesi, M; Brau, J E; Briant, T; Brillet, A; Brinkmann, M; Brisson, V; Brockill, P; Broida, J E; Brooks, A F; Brown, D A; Brown, D D; Brunett, S; Buchanan, C C; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Byer, R L; Cabero, M; Cadonati, L; Cagnoli, G; Cahillane, C; Bustillo, J Calderón; Callister, T A; Calloni, E; Camp, J B; Canepa, M; Canizares, P; Cannon, K C; Cao, H; Cao, J; Capano, C D; Capocasa, E; Carbognani, F; Caride, S; Carney, M F; Diaz, J Casanueva; Casentini, C; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C B; Cerdá-Durán, P; Cerretani, G; Cesarini, E; Chamberlin, S J; Chan, M; Chao, S; Charlton, P; Chase, E; Chassande-Mottin, E; Chatterjee, D; Cheeseboro, B D; Chen, H Y; Chen, X; Chen, Y; Cheng, H-P; Chia, H; Chincarini, A; Chiummo, A; Chmiel, T; Cho, H S; Cho, M; Chow, J H; Christensen, N; Chu, Q; Chua, A J K; Chua, S; Chung, A K W; Chung, S; Ciani, G; Ciolfi, R; Cirelli, C E; Cirone, A; Clara, F; Clark, J A; Clearwater, P; Cleva, F; Cocchieri, C; Coccia, E; Cohadon, P-F; Cohen, D; Colla, A; Collette, C G; Cominsky, L R; Constancio, M; Conti, L; Cooper, S J; Corban, P; Corbitt, T R; Cordero-Carrión, I; Corley, K R; Cornish, N; Corsi, A; Cortese, S; Costa, C A; Coughlin, M W; Coughlin, S B; Coulon, J-P; Countryman, S T; Couvares, P; Covas, P B; Cowan, E E; Coward, D M; Cowart, M J; Coyne, D C; Coyne, R; Creighton, J D E; Creighton, T D; Cripe, J; Crowder, S G; Cullen, T J; Cumming, A; Cunningham, L; Cuoco, E; Dal Canton, T; Dálya, G; Danilishin, S L; D'Antonio, S; Danzmann, K; Dasgupta, A; Da Silva Costa, C F; Dattilo, V; Dave, I; Davier, M; Davis, D; Daw, E J; Day, B; De, S; DeBra, D; Degallaix, J; De Laurentis, M; Deléglise, S; Del Pozzo, W; Demos, N; Denker, T; Dent, T; De Pietri, R; Dergachev, V; De Rosa, R; DeRosa, R T; De Rossi, C; DeSalvo, R; de Varona, O; Devenson, J; Dhurandhar, S; Díaz, M C; Di Fiore, L; Di Giovanni, M; Di Girolamo, T; Di Lieto, A; Di Pace, S; Di Palma, I; Di Renzo, F; Doctor, Z; Dolique, V; Donovan, F; Dooley, K L; Doravari, S; Dorrington, I; Douglas, R; Dovale Álvarez, M; Downes, T P; Drago, M; Dreissigacker, C; Driggers, J C; Du, Z; Ducrot, M; Dupej, P; Dwyer, S E; Edo, T B; Edwards, M C; Effler, A; Eggenstein, H-B; Ehrens, P; Eichholz, J; Eikenberry, S S; Eisenstein, R A; Essick, R C; Estevez, D; Etienne, Z B; Etzel, T; Evans, M; Evans, T M; Factourovich, M; Fafone, V; Fair, H; Fairhurst, S; Fan, X; Farinon, S; Farr, B; Farr, W M; Fauchon-Jones, E J; Favata, M; Fays, M; Fee, C; Fehrmann, H; Feicht, J; Fejer, M M; Fernandez-Galiana, A; Ferrante, I; Ferreira, E C; Ferrini, F; Fidecaro, F; Finstad, D; Fiori, I; Fiorucci, D; Fishbach, M; Fisher, R P; Fitz-Axen, M; Flaminio, R; Fletcher, M; Fong, H; Font, J A; Forsyth, P W F; Forsyth, S S; Fournier, J-D; Frasca, S; Frasconi, F; Frei, Z; Freise, A; Frey, R; Frey, V; Fries, E M; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gabbard, H; Gadre, B U; Gaebel, S M; Gair, J R; Gammaitoni, L; Ganija, M R; Gaonkar, S G; Garcia-Quiros, C; Garufi, F; Gateley, B; Gaudio, S; Gaur, G; Gayathri, V; Gehrels, N; Gemme, G; Genin, E; Gennai, A; George, D; George, J; Gergely, L; Germain, V; Ghonge, S; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, K; Glover, L; Goetz, E; Goetz, R; Gomes, S; Goncharov, B; González, G; Gonzalez Castro, J M; Gopakumar, A; Gorodetsky, M L; Gossan, S E; Gosselin, M; Gouaty, R; Grado, A; Graef, C; Granata, M; Grant, A; Gras, S; Gray, C; Greco, G; Green, A C; Gretarsson, E M; Groot, P; Grote, H; Grunewald, S; Gruning, P; Guidi, G M; Guo, X; Gupta, A; Gupta, M K; Gushwa, K E; Gustafson, E K; Gustafson, R; Halim, O; Hall, B R; Hall, E D; Hamilton, E Z; Hammond, G; Haney, M; Hanke, M M; Hanks, J; Hanna, C; Hannam, M D; Hannuksela, O A; Hanson, J; Hardwick, T; Harms, J; Harry, G M; Harry, I W; Hart, M J; Haster, C-J; Haughian, K; Healy, J; Heidmann, A; Heintze, M C; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Hennig, J; Heptonstall, A W; Heurs, M; Hild, S; Hinderer, T; Hoak, D; Hofman, D; Holt, K; Holz, D E; Hopkins, P; Horst, C; Hough, J; Houston, E A; Howell, E J; Hreibi, A; Hu, Y M; Huerta, E A; Huet, D; Hughey, B; Husa, S; Huttner, S H; Huynh-Dinh, T; Indik, N; Inta, R; Intini, G; Isa, H N; Isac, J-M; Isi, M; Iyer, B R; Izumi, K; Jacqmin, T; Jani, K; Jaranowski, P; Jawahar, S; Jiménez-Forteza, F; Johnson, W W; Jones, D I; Jones, R; Jonker, R J G; Ju, L; Junker, J; Kalaghatgi, C V; Kalogera, V; Kamai, B; Kandhasamy, S; Kang, G; Kanner, J B; Kapadia, S J; Karki, S; Karvinen, K S; Kasprzack, M; Katolik, M; Katsavounidis, E; Katzman, W; Kaufer, S; Kawabe, K; Kéfélian, F; Keitel, D; Kemball, A J; Kennedy, R; Kent, C; Key, J S; Khalili, F Y; Khan, I; Khan, S; Khan, Z; Khazanov, E A; Kijbunchoo, N; Kim, Chunglee; Kim, J C; Kim, K; Kim, W; Kim, W S; Kim, Y-M; Kimbrell, S J; King, E J; King, P J; Kinley-Hanlon, M; Kirchhoff, R; Kissel, J S; Kleybolte, L; Klimenko, S; Knowles, T D; Koch, P; Koehlenbeck, S M; Koley, S; Kondrashov, V; Kontos, A; Korobko, M; Korth, W Z; Kowalska, I; Kozak, D B; Krämer, C; Kringel, V; Krishnan, B; Królak, A; Kuehn, G; Kumar, P; Kumar, R; Kumar, S; Kuo, L; Kutynia, A; Kwang, S; Lackey, B D; Lai, K H; Landry, M; Lang, R N; Lange, J; Lantz, B; Lanza, R K; Lartaux-Vollard, A; Lasky, P D; Laxen, M; Lazzarini, A; Lazzaro, C; Leaci, P; Leavey, S; Lee, C H; Lee, H K; Lee, H M; Lee, H W; Lee, K; Lehmann, J; Lenon, A; Leonardi, M; Leroy, N; Letendre, N; Levin, Y; Li, T G F; Linker, S D; Littenberg, T B; Liu, J; Lo, R K L; Lockerbie, N A; London, L T; Lord, J E; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J D; Lousto, C O; Lovelace, G; Lück, H; Lumaca, D; Lundgren, A P; Lynch, R; Ma, Y; Macas, R; Macfoy, S; Machenschalk, B; MacInnis, M; Macleod, D M; Magaña Hernandez, I; Magaña-Sandoval, F; Magaña Zertuche, L; Magee, R M; Majorana, E; Maksimovic, I; Man, N; Mandic, V; Mangano, V; Mansell, G L; Manske, M; Mantovani, M; Marchesoni, F; Marion, F; Márka, S; Márka, Z; Markakis, C; Markosyan, A S; Markowitz, A; Maros, E; Marquina, A; Martelli, F; Martellini, L; Martin, I W; Martin, R M; Martynov, D V; Mason, K; Massera, E; Masserot, A; Massinger, T J; Masso-Reid, M; Mastrogiovanni, S; Matas, A; Matichard, F; Matone, L; Mavalvala, N; Mazumder, N; McCarthy, R; McClelland, D E; McCormick, S; McCuller, L; McGuire, S C; McIntyre, G; McIver, J; McManus, D J; McNeill, L; McRae, T; McWilliams, S T; Meacher, D; Meadors, G D; Mehmet, M; Meidam, J; Mejuto-Villa, E; Melatos, A; Mendell, G; Mercer, R A; Merilh, E L; Merzougui, M; Meshkov, S; Messenger, C; Messick, C; Metzdorff, R; Meyers, P M; Miao, H; Michel, C; Middleton, H; Mikhailov, E E; Milano, L; Miller, A L; Miller, B B; Miller, J; Millhouse, M; Milovich-Goff, M C; Minazzoli, O; Minenkov, Y; Ming, J; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moffa, D; Moggi, A; Mogushi, K; Mohan, M; Mohapatra, S R P; Montani, M; Moore, C J; Moraru, D; Moreno, G; Morriss, S R; Mours, B; Mow-Lowry, C M; Mueller, G; Muir, A W; Mukherjee, Arunava; Mukherjee, D; Mukherjee, S; Mukund, N; Mullavey, A; Munch, J; Muñiz, E A; Muratore, M; Murray, P G; Napier, K; Nardecchia, I; Naticchioni, L; Nayak, R K; Neilson, J; Nelemans, G; Nelson, T J N; Nery, M; Neunzert, A; Nevin, L; Newport, J M; Newton, G; Ng, K K Y; Nguyen, T T; Nichols, D; Nielsen, A B; Nissanke, S; Nitz, A; Noack, A; Nocera, F; Nolting, D; North, C; Nuttall, L K; Oberling, J; O'Dea, G D; Ogin, G H; Oh, J J; Oh, S H; Ohme, F; Okada, M A; Oliver, M; Oppermann, P; Oram, Richard J; O'Reilly, B; Ormiston, R; Ortega, L F; O'Shaughnessy, R; Ossokine, S; Ottaway, D J; Overmier, H; Owen, B J; Pace, A E; Page, J; Page, M A; Pai, A; Pai, S A; Palamos, J R; Palashov, O; Palomba, C; Pal-Singh, A; Pan, Howard; Pan, Huang-Wei; Pang, B; Pang, P T H; Pankow, C; Pannarale, F; Pant, B C; Paoletti, F; Paoli, A; Papa, M A; Parida, A; Parker, W; Pascucci, D; Pasqualetti, A; Passaquieti, R; Passuello, D; Patil, M; Patricelli, B; Pearlstone, B L; Pedraza, M; Pedurand, R; Pekowsky, L; Pele, A; Penn, S; Perez, C J; Perreca, A; Perri, L M; Pfeiffer, H P; Phelps, M; Piccinni, O J; Pichot, M; Piergiovanni, F; Pierro, V; Pillant, G; Pinard, L; Pinto, I M; Pirello, M; Pitkin, M; Poe, M; Poggiani, R; Popolizio, P; Porter, E K; Post, A; Powell, J; Prasad, J; Pratt, J W W; Pratten, G; Predoi, V; Prestegard, T; Prijatelj, M; Principe, M; Privitera, S; Prodi, G A; Prokhorov, L G; Puncken, O; Punturo, M; Puppo, P; Pürrer, M; Qi, H; Quetschke, V; Quintero, E A; Quitzow-James, R; Raab, F J; Rabeling, D S; Radkins, H; Raffai, P; Raja, S; Rajan, C; Rajbhandari, B; Rakhmanov, M; Ramirez, K E; Ramos-Buades, A; Rapagnani, P; Raymond, V; Razzano, M; Read, J; Regimbau, T; Rei, L; Reid, S; Reitze, D H; Ren, W; Reyes, S D; Ricci, F; Ricker, P M; Rieger, S; Riles, K; Rizzo, M; Robertson, N A; Robie, R; Robinet, F; Rocchi, A; Rolland, L; Rollins, J G; Roma, V J; Romano, J D; Romano, R; Romel, C L; Romie, J H; Rosińska, D; Ross, M P; Rowan, S; Rüdiger, A; Ruggi, P; Rutins, G; Ryan, K; Sachdev, S; Sadecki, T; Sadeghian, L; Sakellariadou, M; Salconi, L; Saleem, M; Salemi, F; Samajdar, A; Sammut, L; Sampson, L M; Sanchez, E J; Sanchez, L E; Sanchis-Gual, N; Sandberg, V; Sanders, J R; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Sauter, O; Savage, R L; Sawadsky, A; Schale, P; Scheel, M; Scheuer, J; Schmidt, J; Schmidt, P; Schnabel, R; Schofield, R M S; Schönbeck, A; Schreiber, E; Schuette, D; Schulte, B W; Schutz, B F; Schwalbe, S G; Scott, J; Scott, S M; Seidel, E; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Shaddock, D A; Shaffer, T J; Shah, A A; Shahriar, M S; Shaner, M B; Shao, L; Shapiro, B; Shawhan, P; Sheperd, A; Shoemaker, D H; Shoemaker, D M; Siellez, K; Siemens, X; Sieniawska, M; Sigg, D; Silva, A D; Singer, L P; Singh, A; Singhal, A; Sintes, A M; Slagmolen, B J J; Smith, B; Smith, J R; Smith, R J E; Somala, S; Son, E J; Sonnenberg, J A; Sorazu, B; Sorrentino, F; Souradeep, T; Spencer, A P; Srivastava, A K; Staats, K; Staley, A; Steinke, M; Steinlechner, J; Steinlechner, S; Steinmeyer, D; Stevenson, S P; Stone, R; Stops, D J; Strain, K A; Stratta, G; Strigin, S E; Strunk, A; Sturani, R; Stuver, A L; Summerscales, T Z; Sun, L; Sunil, S; Suresh, J; Sutton, P J; Swinkels, B L; Szczepańczyk, M J; Tacca, M; Tait, S C; Talbot, C; Talukder, D; Tanner, D B; Tápai, M; Taracchini, A; Tasson, J D; Taylor, J A; Taylor, R; Tewari, S V; Theeg, T; Thies, F; Thomas, E G; Thomas, M; Thomas, P; Thorne, K A; Thrane, E; Tiwari, S; Tiwari, V; Tokmakov, K V; Toland, K; Tonelli, M; Tornasi, Z; Torres-Forné, A; Torrie, C I; Töyrä, D; Travasso, F; Traylor, G; Trinastic, J; Tringali, M C; Trozzo, L; Tsang, K W; Tse, M; Tso, R; Tsukada, L; Tsuna, D; Tuyenbayev, D; Ueno, K; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; van Bakel, N; van Beuzekom, M; van den Brand, J F J; Van Den Broeck, C; Vander-Hyde, D C; van der Schaaf, L; van Heijningen, J V; van Veggel, A A; Vardaro, M; Varma, V; Vass, S; Vasúth, M; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Venugopalan, G; Verkindt, D; Vetrano, F; Viceré, A; Viets, A D; Vinciguerra, S; Vine, D J; Vinet, J-Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Vyatchanin, S P; Wade, A R; Wade, L E; Wade, M; Walet, R; Walker, M; Wallace, L; Walsh, S; Wang, G; Wang, H; Wang, J Z; Wang, W H; Wang, Y F; Ward, R L; Warner, J; Was, M; Watchi, J; Weaver, B; Wei, L-W; Weinert, M; Weinstein, A J; Weiss, R; Wen, L; Wessel, E K; Weßels, P; Westerweck, J; Westphal, T; Wette, K; Whelan, J T; Whiting, B F; Whittle, C; Wilken, D; Williams, D; Williams, R D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M H; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Woehler, J; Wofford, J; Wong, K W K; Worden, J; Wright, J L; Wu, D S; Wysocki, D M; Xiao, S; Yamamoto, H; Yancey, C C; Yang, L; Yap, M J; Yazback, M; Yu, Hang; Yu, Haocun; Yvert, M; Zadrożny, A; Zanolin, M; Zelenova, T; Zendri, J-P; Zevin, M; Zhang, L; Zhang, M; Zhang, T; Zhang, Y-H; Zhao, C; Zhou, M; Zhou, Z; Zhu, S J; Zhu, X J; Zucker, M E; Zweizig, J

2018-03-02

The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude Ω_{GW}(f=25 Hz)=1.8_{-1.3}^{+2.7}×10^{-9} with 90% confidence, compared with Ω_{GW}(f=25 Hz)=1.1_{-0.7}^{+1.2}×10^{-9} from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.
Estimating gravitational radiation from super-emitting compact binary systems

NASA Astrophysics Data System (ADS)

Hanna, Chad; Johnson, Matthew C.; Lehner, Luis

2017-06-01

Binary black hole mergers are among the most violent events in the Universe, leading to extreme warping of spacetime and copious emission of gravitational radiation. Even though black holes are the most compact objects they are not necessarily the most efficient emitters of gravitational radiation in binary systems. The final black hole resulting from a binary black hole merger retains a significant fraction of the premerger orbital energy and angular momentum. A nonvacuum system can in principle shed more of this energy than a black hole merger of equivalent mass. We study these super-emitters through a toy model that accounts for the possibility that the merger creates a compact object that retains a long-lived time-varying quadrupole moment. This toy model may capture the merger of (low mass) neutron stars, but it may also be used to consider more exotic compact binaries. We hope that this toy model can serve as a guide to more rigorous numerical investigations into these systems.
VLT Spectra "Resolve" a Stellar Disk at 25,000 Light-Years Distance

NASA Astrophysics Data System (ADS)

2001-04-01

Unique Observations of a Microlensing Event Summary Like our Sun, stars are large gaseous spheres. However, while we are able to perceive the Sun's disk, all other stars are so far away that they normally appear as points of light . Only specialized observing techniques, like interferometry [1], are able to "resolve" the images of nearby stars and to show them as extended balls of fire. But opportunities may sometimes arise that allow amazing observational feats in this field . Indeed, an international team of astronomers [2] has just "resolved" a single, normal star some 25,000 light years away , or about 1.6 billion times more distant than the Sun [3], by taking advantage of a multiple microlensing event . During such a rare event, the light from the remote star is amplified by the gravity of a faint object that passes in front of it, as seen from the Earth . In fact, this gravitational lens acts as a magnifying glass that focusses different parts of the star's image at different times. Using the FORS1 multi-mode instrument at the 8.2-m VLT ANTU telescope on Paranal during a microlensing event, the team was able to obtain detailed spectra of the different parts of the remote star. In doing so, they managed to probe its gaseous atmosphere at different depths. This is the first time that it has been possible to obtain detailed, spatially resolved spectra across the full face of a normal star other than the Sun [4]. PR Photo 16a/01 : The light-curve of Microlensing Event EROS-BLG-2000-5 . PR Photo 16b/01 : The sky area of EROS-BLG-2000-5. PR Photo 16c/01 : A VLT spectrum of EROS-BLG-2000-5. PR Photo 16d/01 : The observed change of the H-alpha line strength of EROS-BLG-2000-5. A many-faceted success story The following story is about a most unusual astronomical observation and also shows how modern astrophysics works . It combines the study of stellar atmospheres with the intricate optical effects produced by the gravitational field of a binary star in the Milky Way. The successful outcome was dependent on diligent observers in various regions of the world and ultimately on the critical timing of spectral observations with the ESO Very Large Telescope (VLT) at the Paranal Observatory in Chile. Thanks to the effective collaboration among the scientists and a certain measure of good luck, unique data were obtained that are now providing fundamental new insights into stellar astrophysics. The face of a star Distant stars appear as small points of light, even to the largest telescopes on Earth. They are simply too far away to be "resolved" by normal telescopes, and no information can therefore be obtained about what the stellar surfaces look like. This is a fundamental obstacle to the detailed study of stars other than the Sun. We know, however, that the disk of a star does not present itself as a uniform surface. As is the case of the Sun that exhibits variable structures like sunspots (in particular at the time of the present solar maximum), other stars may also have "star-spots" . Another general feature of solar and stellar disks is that they appear fainter towards the periphery. This phenomenon is known as "limb darkening" and is actually a matter of the viewing angle. When we look towards the middle of the solar disk, we see into rather deep and hot layers of its atmosphere. Contrarily, when we view the very edge of the solar disk, we only see the upper, cooler and dimmer parts. Thus, by looking at different areas of its disk, we are able to probe different depths of the solar atmosphere. This in turn permits to determine the structure (temperature, pressure, chemical composition, etc.) of the upper layers of the Sun. For more distant stars, however, their disks appear much too small for this kind of detailed observation. Despite much instrumental progress, therefore, fundamental observational information about stars is still lacking, especially for stars different from the Sun. This is one of the main reasons why the astronomers are thrilled by a new series of spectra from the FORS1 multi-mode instrument at the 8.2-m VLT ANTU telescope at Paranal. They "resolve" for the first time the surface of a normal star some 25,000 light-years away. This amazing observational feat has been possible with some help from a natural "magnifying glass". The road leading to this remarkable result is an instructive and interesting one. Gravitational microlensing ESO PR Photo 16a/01 ESO PR Photo 16a/01 [Preview - JPEG: 361 x 400 pix - 34k] [Normal - JPEG: 721 x 800 pix - 83k] [Hi-Res - JPEG: 2705 x 3000 pix - 536k] Caption : Schematic representation of the lightcurve of the EROS-BLG-2000-5 microlensing event. It represents the changing brightness of a background star, as its light is being amplified by a binary gravitational lens that passes the line-of-sight from the Earth to the star. The ordinate indicates the factor by which the intensity increases during the various phases of the lensing event, as compared to the normal brightness of the star. The moment of the second "caustic crossing" is indicated, during which the image of the star is substantially brighter. Spectral observations were made with the VLT at the times indicated by arrows. For details, see the text. The light from a distant star is affected by the gravity of the objects it passes on its way to us. This effect was predicted by Albert Einstein early last century and observationally confirmed in 1919 when a solar eclipse allowed the study of stars close to the line of sight of the Sun. Accurate positional measurements showed that the light from those remote stars was bent by the Sun's gravitational field. However, the light may not only be deflected, it can also be amplified . In that case, the massive object works like a giant "magnifying lens" that concentrates the light from the distant source. Effects of gravitational optics in space were first observed in 1979. When produced by extended, very heavy clusters of galaxies, they may take the form of large, spectacular arcs and well-separated multiple images, cf. ESO PR Photos 46d/98 and 46f/98 . Less massive lenses, however, produce images with extensions that are too small to be distinguished directly. Such "microlensing" effects occur when a compact body (usually a Milky Way star moving in its galactic orbit) passes almost directly between the observer and a luminous background object (usually also a star). One then sees that the brightness of that object rises and falls as the lens passes across the line-of-sight. The observed light intensity is described by a so-called "light curve", cf. PR Photo 16a/01 . Normally, the lensing object is a faint low-mass star, one of the most common objects in the Milky Way. Microlensing events ESO PR Photo 16b/01 ESO PR Photo 16b/01 [Preview - JPEG: 346 x 400 pix - 44k] [Normal - JPEG: 692 x 800 pix - 112k] [Hi-Res - JPEG: 2596 x 3000 pix - 584k] Caption : A photo of the sky area around the microlensing event EROS-BLG-2000-5 (indicated, near the centre) that is described in this Press Release. Technical information about this photo is available below. In most cases, these low-mass stars are too faint to be directly observed. This is especially so in crowded sky fields in which there are many much brighter stars - including the luminous giant stars that are monitored for microlensing effects. However, the gravity of a low-mass star is strong enough to produce a lensing effect if the geometrical alignment is sufficiently precise. This happens rarely, but by looking at a large number of background stars, it has been possible to detect a fair number of microlensing events during the past few years. International collaborations like Experience pour la Recherche d'Objets Sombres (EROS) , Optical Gravitational Lensing Experiment (OGLE) and Microlensing Observations in Astrophysics (MOA) scan the skies continuously for such microlensing events which typically last from a few weeks to some months. When a star is found to brighten in a way that looks like what is expected from microlensing, they send electronic alerts to other teams like Probing Lensing Anomalies NETwork (PLANET) and Microlensing Planet Search Project (MPS) who then intensively monitor the possible lensing events. One of the main goals of these research programmes is to search for "dark matter" . Indeed, microlensing effects are excellent tools for learning more about this mysterious component of the Universe, as they provide information about lensing objects that otherwise are too faint to be observed. However, microlensing events may also provide very useful information about the background object (the "source"), the light of which is amplified and magnified . When more light is available, more detailed (e.g., spectroscopic) observations can be made. In particular, on rare occasions, it can also help to "resolve" the surface of a distant star. Using distorted lenses If the lensing object is multiple , e.g., a binary star or a star with a planet, the gravitational lens will give rise to interesting phenomena. Whenever the gravitational fields from the two (or more) objects "co-operate", the lensing effect may become distorted and/or unusually strong. Depending on the exact geometry of the lens, i.e. the momentary, relative positions in the sky of the lensing objects and the background object, it is possible that the background source may at some moment be very sharply magnified . In fact, this effect may be so "sharp", that the light from a certain area of the extremely small, apparent disk of a distant star is enhanced much more than that from other areas of the disk. If so, the stellar light registered by the terrestrial telescope will come mainly from that particular area . From optical terminology, such an event is referred to as a "caustic crossing" . However, the exact circumstances are difficult and complex to calculate. The light curve during a lensing event depends on the relative motions of the involved objects or, in other words, on exactly how the distorting and magnifying glass (the lensing object), as seen from the Earth, moves across the background object. In this context, binary lenses are particularly interesting. Not only can they very efficiently enhance the brightness of the source, but there will also be two "caustic crossings" and two associated light maxima. This implies that once the first crossing/maximum has passed, it may be possible to predict when and how the source will be magnified a second time. In that case, the astronomers will have time to prepare for detailed observations at the moment of the second caustic crossing. In particular, this may then include spectroscopic observations that can reveal the structure of the background star. The May 2000 microlensing event ESO PR Photo 16c/01 ESO PR Photo 16c/01 [Preview - JPEG: 400 x 278 pix - 31k] [Normal - JPEG: 800 x 555 pix - 78k] [Hi-Res - JPEG: 3000 x 2081 pix - 528k] Caption : PR Photo 16c/01 shows a spectrum of EROS-BLG-2000-5 , obtained with the FORS1 multi-mode instrument at the 8.2-m VLT ANTU telescope at Paranal on June 25, 2000, before the second caustic crossing described in the text. A small part of the spectrum around the H-alpha line at wavelength 656.2 nm is enlarged in the insert. On 5 May 2000, the EROS group announced an apparently normal microlensing event in a direction a few degrees from the Galactic Centre ( PR Photo 16b/00 ). The brightness of the background star was rising and the PLANET team began to monitor it during its regular operations. About one month later, on 8 June 2000, the MPS team noticed that the event, now designated EROS-BLG-2000-5 , was undergoing an unexpected, sudden and significant brightening. PLANET observers immediately turned their full attention to it, monitoring it continuously from five different observing sites located at suitable longitudes around the Earth. The light curve changed dramatically while the source went through a first caustic crossing ( PR Photo 16a/00 ). On 10 June 2000, the PLANET team alerted the community that this particular event was indeed due to a multiple lens , thus indicating that another light maximum would follow at the second caustic crossing. While continuing to monitor the light curve in order to predict the timing of this second event, the PLANET team contacted ESO with an urgent request to carry out a novel set of observations. The astronomers called attention to the unique possibility of performing detailed spectral observations during the second caustic crossing that could provide information about the chemistry of the stellar atmosphere of the magnified star . ESO concurred and within a day, their observing proposal was granted "Director's Discretionary Time" with the FORS1 spectrograph on the 8.2-m VLT ANTU telescope at the appropriate moment. Some spectra were taken of the background star while it was still magnified, cf. PR Photo 16c/00 , but had not yet made the second caustic crossing. The star was now identified as a cool giant star , located some 25,000 light-years away [3] in the general direction of the Galactic Centre (in the "Galactic Bulge"). Then the team waited. Their predictions indicated that the second caustic crossing might last unusually long, several days rather than a more normal 10-20 hours. The observing plan was therefore changed to ensure that spectra could be taken on four consecutive nights ( PR Photo 16a/00 ) during this caustic crossing. The light curve would then first brighten, and then drop dramatically. During the four nights, the lens would successively magnify different areas of the disk of the cool giant star while "the gravitational magnifying glass slowly moved across it" , as seen from the VLT. First it would mostly be the light from the cool limb of the star that would be amplified, then the hotter middle of the disk, and finally the other, also cooler limb. The VLT observations ESO PR Photo 16d/01 ESO PR Photo 16d/01 [Preview - JPEG: 400 x 270 pix - 28k] [Normal - JPEG: 800 x 540 pix - 63k] [Hi-Res - JPEG: 3000 x 2025 pix - 416k] Caption : The red points are the nightly averages of the strength of the H-alpha absorption line as measured before (point to the left) and during the second caustic crossing. The fully drawn lines represent the expected change, according to two different simulations of the event. The models agree with the data in their general form, but differ on the last night when the trailing limb was crossing the caustic. The two simulations shown differ in their assumptions about the geometry of the event; further data and modeling are now refining these assumptions so that a more quantitative comparison can be made. On each of the four nights beginning on July 4, 5, 6 and 7, 2000, ESO astronomers at Paranal performed two hours of service observations according to the detailed planning of the microlensing team. Spectra were successfully taken of the giant star with the multi-mode FORS1 instrument at the 8.2-m VLT ANTU telescope at the moment of the second caustic crossing. The magnitude was about I=13 at the brightness peak, dropping about 2 magnitudes towards the end of the period ( PR Photo 16a/01 ). In a first scientific assessment of these unique spectra, the team concentrated on an absorption line in the red spectral region (the "H-alpha" line) that is produced by hydrogen in the stellar atmosphere. They found a clear change in the strength of this line of the source star during the four nights ( PR Photo 16d/01 ). No such variations were seen in the spectra of neighbouring stars that were observed simultaneously, providing a secure check that the observed changes are real. The astronomers then went on to interpret this change. For this they performed various simulations by means of a computer model of the atmosphere of the cool giant star, applying the expected effects of the lensing and then comparing with the observed spectra. The expected changes in the strength of the H-alpha absorption line during the crossing from two simple simulations are plotted as lines over the observed data in PR Photo 16d/01 . The observed changes of the H-alpha line during the caustic crossing agree well with the model calculations . During this event, the microlens magnifies successive areas of the stellar disk particularly strongly. To begin with, the light from the relatively cool, leading limb of the star dominates the registered spectrum - and here the absorption line strength drops slightly, exactly as expected. It then becomes stronger as the hotter areas near the middle of the disk "come into focus" and then again decreases when the cooler trailing limb is strongly magnified. This is the first time that this effect has ever been measured for all phases of a caustic crossing. More to come More quantitative predictions of the modeling will now be carried out, refining the geometry of the caustic crossing and involving many more spectral lines. This will allow a sophisticated tomographic analysis of the atmosphere of this star. For this, the detailed brightness measurements that were collected from over two thousand observations of EROS-BLG-2000-5 by PLANET observers in Tasmania, Western Australia, South Africa, Chile and the United States will be of great help in determining better the exact geometry of the event. In due time, the VLT spectra data will then make it possible to test directly the best models of stellar atmospheres now devised by astronomers. Observations like these are very important because they allow detailed investigation of a stellar atmosphere other than that of the Sun. It is remarkable that this is based on the "resolution" of the disk of a star over 25000 light-years away, i.e. about 1.6 billion times more distant than our own Sun [4]. More information Further detailed information is available at the PLANET website and in a research paper ( "H-alpha Equivalent Width Variations across the Face of a Microlensed K Giant in the Galactic Bulge" ) that appeared in the April 1, 2001 issue of the "Astrophysical Journal" (available on the web at ApJL 550, L173 or astro-ph0011380). Notes [1] Note the recent ESO Press Release 06/01 about the VLT Interferometer. Observations of binary stars that undergo eclipses from time to time also allow indirect studies of the surfaces of the two components; such objects, however, influence each other and cannot be characterized as "normal" stars. [2] The team (the PLANET collaboration) consists of Michael Albrow , Kailash C. Sahu (Space Telescope Science Institute, Baltimore, MD, USA) Jin H. An (Dept. of Astronomy, Ohio State University, Columbus, OH, USA), Jean-Philippe Beaulieu (Institut d'Astrophysique de Paris, France), John A. R. Caldwell , John W. Menzies , Pierre Vermaak (South African Astronomical Observatory, Cape Town, South Africa), Martin Dominik , Penny D. Sackett (Kapteyn Astronomical Institute, Groningen, The Netherlands) , John Greenhill , Kym Hill , Stephen Kane , Robert Watson (University of Tasmania, Hobart, Tasmania, Australia), Ralph Martin , Andrew Williams (Perth Observatory, Australia), Karen Pollard (Physics Dept., Gettysburg College, PA, USA) and Peter H. Hauschildt (Dept. of Physics and Astronomy & Center for Simulational Physics, University of Georgia, Athens, GA, USA). [3] The distance to the Sun is 149.6 million kilometres; 25,000 light-years = 240,000,000,000,000,000 kilometres. 1 billion = 1000 million. [4] The diameter of the cool giant star is approx. 15 million km (about ten times that of the Sun). At the indicated distance, 25,000 light-years, this corresponds to a very small angle, about 10 micro-arcsec. This is equal to the angle subtended by a human hair (diameter 50 microns = 0.05 mm) at a distance of 1000 km. Technical information about the photos PR Photo 16b/01 shows a 0.25-sec acquisition exposure of EROS-BLG-2000-5 , obtained with VLT ANTU + FORS1 in order to set up the spectrograph slit for the subsequent spectral exposures. The filter was Bessell-I (wavelength about 900 nm) and the field measures about 2 x 2 arcmin 2. North is up and East is left. The FORS1 spectrum shown in PR Photo 16c/01 is a composite of 300-sec exposures taken with with the 600B (spectral interval 390 - 580 nm), 600R (538 - 753 nm) and 600I (705 - 918 nm) gratings; the insert covers a 10 nm wide region near H-alpha.
Formation of the first three gravitational-wave observations through isolated binary evolution

PubMed Central

Stevenson, Simon; Vigna-Gómez, Alejandro; Mandel, Ilya; Barrett, Jim W.; Neijssel, Coenraad J.; Perkins, David; de Mink, Selma E.

2017-01-01

During its first four months of taking data, Advanced LIGO has detected gravitational waves from two binary black hole mergers, GW150914 and GW151226, along with the statistically less significant binary black hole merger candidate LVT151012. Here we use the rapid binary population synthesis code COMPAS to show that all three events can be explained by a single evolutionary channel—classical isolated binary evolution via mass transfer including a common envelope phase. We show all three events could have formed in low-metallicity environments (Z=0.001) from progenitor binaries with typical total masses ≳160M⊙, ≳60M⊙ and ≳90M⊙, for GW150914, GW151226 and LVT151012, respectively. PMID:28378739
Merging Black Holes and Gravitational Waves

NASA Technical Reports Server (NTRS)

Centrella, Joan

2009-01-01

This talk will focus on simulations of binary black hole mergers and the gravitational wave signals they produce. Applications to gravitational wave detection with LISA, and electronagnetic counterparts, will be highlighted.
Mathematics of gravitational lensing: multiple imaging and magnification

NASA Astrophysics Data System (ADS)

Petters, A. O.; Werner, M. C.

2010-09-01

The mathematical theory of gravitational lensing has revealed many generic and global properties. Beginning with multiple imaging, we review Morse-theoretic image counting formulas and lower bound results, and complex-algebraic upper bounds in the case of single and multiple lens planes. We discuss recent advances in the mathematics of stochastic lensing, discussing a general formula for the global expected number of minimum lensed images as well as asymptotic formulas for the probability densities of the microlensing random time delay functions, random lensing maps, and random shear, and an asymptotic expression for the global expected number of micro-minima. Multiple imaging in optical geometry and a spacetime setting are treated. We review global magnification relation results for model-dependent scenarios and cover recent developments on universal local magnification relations for higher order caustics.
Direct detection of a microlens in the Milky Way.

PubMed

Alcock, C; Allsman, R A; Alves, D R; Axelrod, T S; Becker, A C; Bennett, D P; Cook, K H; Drake, A J; Freeman, K C; Geha, M; Griest, K; Keller, S C; Lehner, M J; Marshall, S L; Minniti, D; Nelson, C A; Peterson, B A; Popowski, P; Pratt, M R; Quinn, P J; Stubbs, C W; Sutherland, W; Tomaney, A B; Vandehei, T; Welch, D

2001-12-06

The nature of dark matter remains mysterious, with luminous material accounting for at most approximately 25 per cent of the baryons in the Universe. We accordingly undertook a survey looking for the microlensing of stars in the Large Magellanic Cloud (LMC) to determine the fraction of Galactic dark matter contained in massive compact halo objects (MACHOs). The presence of the dark matter would be revealed by gravitational lensing of the light from an LMC star as the foreground dark matter moves across the line of sight. The duration of the lensing event is the key observable parameter, but gives non-unique solutions when attempting to estimate the mass, distance and transverse velocity of the lens. The survey results to date indicate that between 8 and 50 per cent of the baryonic mass of the Galactic halo is in the form of MACHOs (ref. 3), but removing the degeneracy by identifying a lensing object would tighten the constraints on the mass in MACHOs. Here we report a direct image of a microlens, revealing it to be a nearby low-mass star in the disk of the Milky Way. This is consistent with the expected frequency of nearby stars acting as lenses, and demonstrates a direct determination of a lens mass from a microlensing event. Complete solutions such as this for halo microlensing events will probe directly the nature of the MACHOs.
Optical eigenmodes for illumination & imaging

NASA Astrophysics Data System (ADS)

Kosmeier, Sebastian

Gravitational Microlensing, as a technique for detecting Extrasolar Planets, is recognised for its potential in discovering small-mass planets similar to Earth, at a distance of a few Astronomical Units from their host stars. However, analysing the data from microlensing events (which statistically rarely reveal planets) is complex and requires continued and intensive use of various networks of telescopes working together in order to observe the phenomenon. As such the techniques are constantly being developed and refined; this project outlines some steps of the careful analysis required to model an event and ensure the best quality data is used in the fitting. A quantitative investigation into increasing the quality of the original photometric data available from any microlensing event demonstrates that 'lucky imaging' can lead to a marked improvement in the signal to noise ratio of images over standard imaging techniques, which could result in more accurate models and thus the calculation of more accurate planetary parameters. In addition, a simulation illustrating the effects of atmospheric turbulence on exposures was created, and expanded upon to give an approximation of the lucky imaging technique. This further demonstrated the advantages of lucky images which are shown to potentially approach the quality of those expected from diffraction limited photometry. The simulation may be further developed for potential future use as a 'theoretical lucky imager' in our research group, capable of producing and analysing synthetic exposures through customisable conditions.
Gravitational waveforms for neutron star binaries from binary black hole simulations

NASA Astrophysics Data System (ADS)

Barkett, Kevin; Scheel, Mark; Haas, Roland; Ott, Christian; Bernuzzi, Sebastiano; Brown, Duncan; Szilagyi, Bela; Kaplan, Jeffrey; Lippuner, Jonas; Muhlberger, Curran; Foucart, Francois; Duez, Matthew

2016-03-01

Gravitational waves from binary neutron star (BNS) and black-hole/neutron star (BHNS) inspirals are primary sources for detection by the Advanced Laser Interferometer Gravitational-Wave Observatory. The tidal forces acting on the neutron stars induce changes in the phase evolution of the gravitational waveform, and these changes can be used to constrain the nuclear equation of state. Current methods of generating BNS and BHNS waveforms rely on either computationally challenging full 3D hydrodynamical simulations or approximate analytic solutions. We introduce a new method for computing inspiral waveforms for BNS/BHNS systems by adding the post-Newtonian (PN) tidal effects to full numerical simulations of binary black holes (BBHs), effectively replacing the non-tidal terms in the PN expansion with BBH results. Comparing a waveform generated with this method against a full hydrodynamical simulation of a BNS inspiral yields a phase difference of < 1 radian over ~ 15 orbits. The numerical phase accuracy required of BNS simulations to measure the accuracy of the method we present here is estimated as a function of the tidal deformability parameter λ.
Gravitational waveforms for neutron star binaries from binary black hole simulations

NASA Astrophysics Data System (ADS)

Barkett, Kevin; Scheel, Mark A.; Haas, Roland; Ott, Christian D.; Bernuzzi, Sebastiano; Brown, Duncan A.; Szilágyi, Béla; Kaplan, Jeffrey D.; Lippuner, Jonas; Muhlberger, Curran D.; Foucart, Francois; Duez, Matthew D.

2016-02-01

Gravitational waves from binary neutron star (BNS) and black hole/neutron star (BHNS) inspirals are primary sources for detection by the Advanced Laser Interferometer Gravitational-Wave Observatory. The tidal forces acting on the neutron stars induce changes in the phase evolution of the gravitational waveform, and these changes can be used to constrain the nuclear equation of state. Current methods of generating BNS and BHNS waveforms rely on either computationally challenging full 3D hydrodynamical simulations or approximate analytic solutions. We introduce a new method for computing inspiral waveforms for BNS/BHNS systems by adding the post-Newtonian (PN) tidal effects to full numerical simulations of binary black holes (BBHs), effectively replacing the nontidal terms in the PN expansion with BBH results. Comparing a waveform generated with this method against a full hydrodynamical simulation of a BNS inspiral yields a phase difference of <1 radian over ˜15 orbits. The numerical phase accuracy required of BNS simulations to measure the accuracy of the method we present here is estimated as a function of the tidal deformability parameter λ .
Gravitational radiation from compact binary systems in screened modified gravity

NASA Astrophysics Data System (ADS)

Zhang, Xing; Liu, Tan; Zhao, Wen

2017-05-01

Screened modified gravity (SMG) is a kind of scalar-tensor theory with screening mechanisms, which can suppress the fifth force in dense regions and allow theories to evade the solar system and laboratory tests. In this paper, we investigate how the screening mechanisms in SMG affect the gravitational radiation damping effects, calculate in detail the rate of the energy loss due to the emission of tensor and scalar gravitational radiations, and derive their contributions to the change in the orbital period of the binary system. We find that the scalar radiation depends on the screened parameters and the propagation speed of scalar waves, and the scalar dipole radiation dominates the orbital decay of the binary system. For strongly self-gravitating bodies, all effects of scalar sector are strongly suppressed by the screening mechanisms in SMG. By comparing our results to observations of binary system PSR J 1738 +0333 , we place the stringent constraints on the screening mechanisms in SMG. As an application of these results, we focus on three specific models of SMG (chameleon, symmetron, and dilaton), and derive the constraints on the model parameters, respectively.

Constraints on Horndeski theory using the observations of Nordtvedt effect, Shapiro time delay and binary pulsars

NASA Astrophysics Data System (ADS)

Hou, Shaoqi; Gong, Yungui

2018-03-01

Alternative theories of gravity not only modify the polarization contents of the gravitational wave, but also affect the motions of the stars and the energy radiated away via the gravitational radiation. These aspects leave imprints in the observational data, which enables the test of general relativity and its alternatives. In this work, the Nordtvedt effect and the Shapiro time delay are calculated in order to constrain Horndeski theory using the observations of lunar laser ranging experiments and Cassini time-delay data. The effective stress-energy tensor is also obtained using the method of Isaacson. Gravitational wave radiation of a binary system is calculated, and the change of the period of a binary system is deduced for the elliptical orbit. These results can be used to set constraints on Horndeski theory with the observations of binary systems, such as PSR J1738 + 0333. Constraints have been obtained for some subclasses of Horndeski theory, in particular, those satisfying the gravitational wave speed limits from GW170817 and GRB 170817A.
Binary Black Holes, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Centrella, Joan

2007-01-01

Massive black hole (MBH) binaries are found at the centers of most galaxies. MBH mergers trace galaxy mergers and are strong sources of gravitational waves. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities. causing them to crash well before the black hole:, in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This presentation shows how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. Focus is on the recent advances that that reveal these waveforms, and the potential for discoveries that arises when these sources are observed by LIGO and LISA.
Modelling Gravitational Radiation from Binary Black Holes

NASA Technical Reports Server (NTRS)

Centrella, Joan

2006-01-01

The final merger and coalescence of binary black holes is a key source of strong gravitational waves for the LISA mission. Observing these systems will allow us to probe the formation of cosmic structure to high redshifts and test general relativity directly in the strong-field, dynamical regime. Recently, major breakthroughs have been made in modeling black hole mergers using numerical relativity. This talk will survey these exciting developments, focusing on the gravitational waveforms and the recoil kicks produced from non-equal mass mergers.
Black Hole Mergers in Galactic Nuclei Induced by the Eccentric Kozai–Lidov Effect

NASA Astrophysics Data System (ADS)

Hoang, Bao-Minh; Naoz, Smadar; Kocsis, Bence; Rasio, Frederic A.; Dosopoulou, Fani

2018-04-01

Nuclear star clusters around a central massive black hole (MBH) are expected to be abundant in stellar black hole (BH) remnants and BH–BH binaries. These binaries form a hierarchical triple system with the central MBH, and gravitational perturbations from the MBH can cause high-eccentricity excitation in the BH–BH binary orbit. During this process, the eccentricity may approach unity, and the pericenter distance may become sufficiently small so that gravitational-wave emission drives the BH–BH binary to merge. In this work, we construct a simple proof-of-concept model for this process, and specifically, we study the eccentric Kozai–Lidov mechanism in unequal-mass, soft BH–BH binaries. Our model is based on a set of Monte Carlo simulations for BH–BH binaries in galactic nuclei, taking into account quadrupole- and octupole-level secular perturbations, general relativistic precession, and gravitational-wave emission. For a typical steady-state number of BH–BH binaries, our model predicts a total merger rate of ∼1–3 {Gpc} ‑3 {yr} ‑1, depending on the assumed density profile in the nucleus. Thus, our mechanism could potentially compete with other dynamical formation processes for merging BH–BH binaries, such as the interactions of stellar BHs in globular clusters or in nuclear star clusters without an MBH.
Tests of general relativity from gravitational wave observations of binary black holes

NASA Astrophysics Data System (ADS)

Del Pozzo, Walter

2017-01-01

Gravitational waves emitted during the coalescence of compact binary systems carry a wealth of information about the merging objects, the remnant object as well as their interaction with space-time. The description of the dynamics of such systems is based on solutions of the theory of general relativity. For any given physical configuration of masses, spins and orbital motion, general relativity predicts the dynamical evolution of the binary system as well as the corresponding gravitational wave signal. During the coalescence of extremely compact objects such as binary black holes, the typical curvature and velocity at play are such that, from the observation of the gravitational wave signal, we can access the most extreme dynamical regimes of gravity. In such conditions, we can test our understanding of gravity by looking for potential departures between the solutions of general relativity and the actual dynamics of space-time. The LIGO observations GW150914 and GW151226 provided wonderful testing grounds for general relativity in the, up to now unaccessible, strong-field dynamical regime of gravity. During my talk, I will review and discuss several of the tests that have been devised to detect violations of the predictions of general relativity from the observation of gravitational waves from coalescing binary systems. The discussion will be based on the results of the analysis of GW150914 and GW151226. Finally, I will conclude by discussing some of the future prospects of extending the current state-of-the-art methodologies to further aspects of general relativity.
Are some BL Lacs artefacts of gravitational lensing?

PubMed

Ostriker, J P; Vietri, M

1990-03-01

WE suggested in 1985 that a significant fraction of BL Lacertae objects, a kind of lineless quasar, seen in nearby galaxies are in fact images, gravitationally lensed and substantially amplified by stars in the nearby galaxy, of background objects, optically violent variable (OVV) quasars at redshifts z > 1 (ref. 1). This hypothesis was made on the basis of certain general similarities between BL Lacs and O Ws, but for two recently observed BL Lacs(2,3) a strong case can be made that the accompanying elliptical galaxy is a foreground object. In addition, we argue that the distribution of BL Lac redshifts is hard to understand without gravitational lensing, unless we happen to be at a very local maximum of the spatial cosmic distribution of BL Lacs. Our analysis also indicates that the galaxies whose stars are likely to act as microlenses will be found in two peaks, one nearby, with redshift 0.05-0.10, and the other near the distant quasar.
Gamma-ray-burst beaming and gravitational-wave observations.

PubMed

Chen, Hsin-Yu; Holz, Daniel E

2013-11-01

Using the observed rate of short-duration gamma-ray bursts (GRBs) it is possible to make predictions for the detectable rate of compact binary coalescences in gravitational-wave detectors. We show that the nondetection of mergers in the existing LIGO/Virgo data constrains the beaming angles and progenitor masses of gamma-ray bursts, although these limits are fully consistent with existing expectations. We make predictions for the rate of events in future networks of gravitational-wave observatories, finding that the first detection of a neutron-star-neutron-star binary coalescence associated with the progenitors of short GRBs is likely to happen within the first 16 months of observation, even in the case of only two observatories (e.g., LIGO-Hanford and LIGO-Livingston) operating at intermediate sensitivities (e.g., advanced LIGO design sensitivity, but without signal recycling mirrors), and assuming a conservative distribution of beaming angles (e.g., all GRBs beamed within θ(j) = 30°). Less conservative assumptions reduce the waiting time until first detection to a period of weeks to months, with an event detection rate of >/~10/yr. Alternatively, the compact binary coalescence model of short GRBs can be ruled out if a binary is not seen within the first two years of operation of a LIGO-Hanford, LIGO-Livingston, and Virgo network at advanced design sensitivity. We also demonstrate that the gravitational wave detection rate of GRB triggered sources (i.e., those seen first in gamma rays) is lower than the rate of untriggered events (i.e., those seen only in gravitational waves) if θ(j)≲30°, independent of the noise curve, network configuration, and observed GRB rate. The first detection in gravitational waves of a binary GRB progenitor is therefore unlikely to be associated with the observation of a GRB.
Reducing the number of templates for aligned-spin compact binary coalescence gravitational wave searches using metric-agnostic template nudging

NASA Astrophysics Data System (ADS)

Indik, Nathaniel; Fehrmann, Henning; Harke, Franz; Krishnan, Badri; Nielsen, Alex B.

2018-06-01

Efficient multidimensional template placement is crucial in computationally intensive matched-filtering searches for gravitational waves (GWs). Here, we implement the neighboring cell algorithm (NCA) to improve the detection volume of an existing compact binary coalescence (CBC) template bank. This algorithm has already been successfully applied for a binary millisecond pulsar search in data from the Fermi satellite. It repositions templates from overdense regions to underdense regions and reduces the number of templates that would have been required by a stochastic method to achieve the same detection volume. Our method is readily generalizable to other CBC parameter spaces. Here we apply this method to the aligned-single-spin neutron star-black hole binary coalescence inspiral-merger-ringdown gravitational wave parameter space. We show that the template nudging algorithm can attain the equivalent effectualness of the stochastic method with 12% fewer templates.
Eccentric, nonspinning, inspiral, Gaussian-process merger approximant for the detection and characterization of eccentric binary black hole mergers

NASA Astrophysics Data System (ADS)

Huerta, E. A.; Moore, C. J.; Kumar, Prayush; George, Daniel; Chua, Alvin J. K.; Haas, Roland; Wessel, Erik; Johnson, Daniel; Glennon, Derek; Rebei, Adam; Holgado, A. Miguel; Gair, Jonathan R.; Pfeiffer, Harald P.

2018-01-01

We present ENIGMA, a time domain, inspiral-merger-ringdown waveform model that describes nonspinning binary black holes systems that evolve on moderately eccentric orbits. The inspiral evolution is described using a consistent combination of post-Newtonian theory, self-force and black hole perturbation theory. Assuming eccentric binaries that circularize prior to coalescence, we smoothly match the eccentric inspiral with a stand-alone, quasicircular merger, which is constructed using machine learning algorithms that are trained with quasicircular numerical relativity waveforms. We show that ENIGMA reproduces with excellent accuracy the dynamics of quasicircular compact binaries. We validate ENIGMA using a set of Einstein Toolkit eccentric numerical relativity waveforms, which describe eccentric binary black hole mergers with mass-ratios between 1 ≤q ≤5.5 , and eccentricities e0≲0.2 ten orbits before merger. We use this model to explore in detail the physics that can be extracted with moderately eccentric, nonspinning binary black hole mergers. In particular, we use ENIGMA to show that the gravitational wave transients GW150914, GW151226, GW170104, GW170814 and GW170608 can be effectively recovered with spinning, quasicircular templates if the eccentricity of these events at a gravitational wave frequency of 10 Hz satisfies e0≤{0.175 ,0.125 ,0.175 ,0.175 ,0.125 }, respectively. We show that if these systems have eccentricities e0˜0.1 at a gravitational wave frequency of 10 Hz, they can be misclassified as quasicircular binaries due to parameter space degeneracies between eccentricity and spin corrections. Using our catalog of eccentric numerical relativity simulations, we discuss the importance of including higher-order waveform multipoles in gravitational wave searches of eccentric binary black hole mergers.
The Formation and Gravitational-wave Detection of Massive Stellar Black Hole Binaries

NASA Astrophysics Data System (ADS)

Belczynski, Krzysztof; Buonanno, Alessandra; Cantiello, Matteo; Fryer, Chris L.; Holz, Daniel E.; Mandel, Ilya; Miller, M. Coleman; Walczak, Marek

2014-07-01

If binaries consisting of two ~100 M ⊙ black holes exist, they would serve as extraordinarily powerful gravitational-wave sources, detectable to redshifts of z ~ 2 with the advanced LIGO/Virgo ground-based detectors. Large uncertainties about the evolution of massive stars preclude definitive rate predictions for mergers of these massive black holes. We show that rates as high as hundreds of detections per year, or as low as no detections whatsoever, are both possible. It was thought that the only way to produce these massive binaries was via dynamical interactions in dense stellar systems. This view has been challenged by the recent discovery of several >~ 150 M ⊙ stars in the R136 region of the Large Magellanic Cloud. Current models predict that when stars of this mass leave the main sequence, their expansion is insufficient to allow common envelope evolution to efficiently reduce the orbital separation. The resulting black hole-black hole binary remains too wide to be able to coalesce within a Hubble time. If this assessment is correct, isolated very massive binaries do not evolve to be gravitational-wave sources. However, other formation channels exist. For example, the high multiplicity of massive stars, and their common formation in relatively dense stellar associations, opens up dynamical channels for massive black hole mergers (e.g., via Kozai cycles or repeated binary-single interactions). We identify key physical factors that shape the population of very massive black hole-black hole binaries. Advanced gravitational-wave detectors will provide important constraints on the formation and evolution of very massive stars.
Binary Black Holes, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Centrella, Joan

2007-01-01

This viewgraph presentation reviews the massive black hole (MBH) binaries that are found at the center of most galaxies, "astronomical messenger", gravitational waves (GW), and the use of numerical relativity understand the features of these phenomena. The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity.. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Gravitational waves from rotating neutron stars and compact binary systems

NASA Astrophysics Data System (ADS)

Wade, Leslie E., IV

It is widely anticipated that the first direct detections of gravitational waves will be made by advanced gravitational-wave detectors, such as the two Laser Interferometer Gravitational-wave Observatories (LIGO) and the Virgo interferometer. In preparation for the advanced detector era, I have worked on both detection and post-detection efforts involving two gravitational wave sources: isolated rotating neutron stars (NSs) and compact binary coalescences (CBCs). My dissertation includes three main research projects: 1) a population synthesis study assessing the detectability of isolated NSs, 2) a CBC search for intermediate-mass black-hole binaries (IMBHBs), and 3) new methods for directly measuring the neutron-star (NS) equation of state (EOS). Direct detections of gravitational waves will enrich our current astrophysical knowledge. One such contribution will be through population synthesis of isolated NSs. My collaborators and I show that advanced gravitational-wave detectors can be used to constrain the properties of the Galactic NS population. Gravitational wave detections can also shine light on a currently mysterious astrophysical object: intermediate mass black holes. In developing the IMBHB search, we performed a mock data challenge where signals with total masses up to a few hundred solar masses were injected into recolored data from LIGO's sixth science run. Since this is the first time a matched filter search has been developed to search for IMBHBs, I discuss what was learned during the mock data challenge and how we plan to improve the search going forward. The final aspect of my dissertation focuses on important post-detection science. I present results for a new method of directly measuring the NS EOS. This is done by estimating the parameters of a 4-piece polytropic EOS model that matches theoretical EOS candidates to a few percent. We show that advanced detectors will be capable of measuring the NS radius to within a kilometer for stars with canonical masses. However, this can only be accomplished with binary NS waveform models that are accurate to the rich EOS physics that happens near merger. We show that the waveforms typically used to model binary NS systems result in unavoidable systematic error that can significantly bias the estimation of the NS EOS.
Gravitational Waves and Multi-Messenger Astronomy

NASA Technical Reports Server (NTRS)

Centrella, Joan M.

2010-01-01

Gravitational waves are produced by a wide variety of sources throughout the cosmos, including the mergers of black hole and neutron star binaries/compact objects spiraling into central black holes in galactic nuclei, close compact binaries/and phase transitions and quantum fluctuations in the early universe. Observing these signals can bring new, and often very precise, information about their sources across vast stretches of cosmic time. In this talk we will focus on thee opening of this gravitational-wave window on the universe, highlighting new opportunities for discovery and multi-messenger astronomy.
The Lagrange Points in a Binary Black Hole System: Applications to Electromagnetic Signatures

NASA Technical Reports Server (NTRS)

Schnittman, Jeremy

2010-01-01

We study the stability and evolution of the Lagrange points L_4 and L-5 in a black hole (BH) binary system, including gravitational radiation. We find that gas and stars can be shepherded in with the BH system until the final moments before merger, providing the fuel for a bright electromagnetic counterpart to a gravitational wave signal. Other astrophysical signatures include the ejection of hyper-velocity stars, gravitational collapse of globular clusters, and the periodic shift of narrow emission lines in AGN.
GW150914: Implications for the Stochastic Gravitational-Wave Background from Binary Black Holes

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Bustillo, J. Calderón; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Diaz, J. Casanueva; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Baiardi, L. Cerboni; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Canton, T. Dal; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; DeRosa, R. T.; De Rosa, R.; DeSalvo, R.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gatto, A.; Gaur, G.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Castro, J. M. Gonzalez; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Haris, K.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, C.; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Logue, J.; Lombardi, A. L.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Phelps, M.; Piccinni, O.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2016-04-01

The LIGO detection of the gravitational wave transient GW150914, from the inspiral and merger of two black holes with masses ≳30 M⊙, suggests a population of binary black holes with relatively high mass. This observation implies that the stochastic gravitational-wave background from binary black holes, created from the incoherent superposition of all the merging binaries in the Universe, could be higher than previously expected. Using the properties of GW150914, we estimate the energy density of such a background from binary black holes. In the most sensitive part of the Advanced LIGO and Advanced Virgo band for stochastic backgrounds (near 25 Hz), we predict ΩGW(f =25 Hz )=1. 1-0.9+2.7×10-9 with 90% confidence. This prediction is robustly demonstrated for a variety of formation scenarios with different parameters. The differences between models are small compared to the statistical uncertainty arising from the currently poorly constrained local coalescence rate. We conclude that this background is potentially measurable by the Advanced LIGO and Advanced Virgo detectors operating at their projected final sensitivity.
GW150914: Implications for the Stochastic Gravitational-Wave Background from Binary Black Holes.

PubMed

Abbott, B P; Abbott, R; Abbott, T D; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V B; Affeldt, C; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Aiello, L; Ain, A; Ajith, P; Allen, B; Allocca, A; Altin, P A; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C C; Areeda, J S; Arnaud, N; Arun, K G; Ascenzi, S; Ashton, G; Ast, M; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Babak, S; Bacon, P; Bader, M K M; Baker, P T; Baldaccini, F; Ballardin, G; Ballmer, S W; Barayoga, J C; Barclay, S E; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barta, D; Bartlett, J; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Baune, C; Bavigadda, V; Bazzan, M; Behnke, B; Bejger, M; Bell, A S; Bell, C J; Berger, B K; Bergman, J; Bergmann, G; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Birch, J; Birney, R; Biscans, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; 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Drago, M; Drever, R W P; Driggers, J C; Du, Z; Ducrot, M; Dwyer, S E; Edo, T B; Edwards, M C; Effler, A; Eggenstein, H-B; Ehrens, P; Eichholz, J; Eikenberry, S S; Engels, W; Essick, R C; Etzel, T; Evans, M; Evans, T M; Everett, R; Factourovich, M; Fafone, V; Fair, H; Fairhurst, S; Fan, X; Fang, Q; Farinon, S; Farr, B; Farr, W M; Favata, M; Fays, M; Fehrmann, H; Fejer, M M; Ferrante, I; Ferreira, E C; Ferrini, F; Fidecaro, F; Fiori, I; Fiorucci, D; Fisher, R P; Flaminio, R; Fletcher, M; Fournier, J-D; Franco, S; Frasca, S; Frasconi, F; Frei, Z; Freise, A; Frey, R; Frey, V; Fricke, T T; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gabbard, H A G; Gair, J R; Gammaitoni, L; Gaonkar, S G; Garufi, F; Gatto, A; Gaur, G; Gehrels, N; Gemme, G; Gendre, B; Genin, E; Gennai, A; George, J; Gergely, L; Germain, V; Ghosh, Archisman; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, K; Glaefke, A; Goetz, E; Goetz, R; Gondan, L; González, G; Castro, J M Gonzalez; Gopakumar, A; Gordon, N A; Gorodetsky, M L; 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Wade, A R; Wade, L E; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, G; Wang, H; Wang, M; Wang, X; Wang, Y; Ward, R L; Warner, J; Was, M; Weaver, B; Wei, L-W; Weinert, M; Weinstein, A J; Weiss, R; Welborn, T; Wen, L; Weßels, P; Westphal, T; Wette, K; Whelan, J T; White, D J; Whiting, B F; Williams, R D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M H; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Worden, J; Wright, J L; Wu, G; Yablon, J; Yam, W; Yamamoto, H; Yancey, C C; Yap, M J; Yu, H; Yvert, M; Zadrożny, A; Zangrando, L; Zanolin, M; Zendri, J-P; Zevin, M; Zhang, F; Zhang, L; Zhang, M; Zhang, Y; Zhao, C; Zhou, M; Zhou, Z; Zhu, X J; Zucker, M E; Zuraw, S E; Zweizig, J

2016-04-01

The LIGO detection of the gravitational wave transient GW150914, from the inspiral and merger of two black holes with masses ≳30M_{⊙}, suggests a population of binary black holes with relatively high mass. This observation implies that the stochastic gravitational-wave background from binary black holes, created from the incoherent superposition of all the merging binaries in the Universe, could be higher than previously expected. Using the properties of GW150914, we estimate the energy density of such a background from binary black holes. In the most sensitive part of the Advanced LIGO and Advanced Virgo band for stochastic backgrounds (near 25 Hz), we predict Ω_{GW}(f=25 Hz)=1.1_{-0.9}^{+2.7}×10^{-9} with 90% confidence. This prediction is robustly demonstrated for a variety of formation scenarios with different parameters. The differences between models are small compared to the statistical uncertainty arising from the currently poorly constrained local coalescence rate. We conclude that this background is potentially measurable by the Advanced LIGO and Advanced Virgo detectors operating at their projected final sensitivity.
Improved Bounds on Violation of the Strong Equivalence Principle

NASA Technical Reports Server (NTRS)

Arzoumanian, Z.

2002-01-01

I describe a unique, 20-year-long timing program for the binary pulsar B0655+64, the stalwart control experiment for measurements of gravitational radiation damping in relativistic neutron-star binaries. Observed limits on evolution of the B0655+64 orbit provide new bounds on the existence of dipolar gravitational radiation, and hence on violation of the Strong Equivalence Principle.
Probing small-scale structure in galaxies with strong gravitational lensing

NASA Astrophysics Data System (ADS)

Congdon, Arthur Benjamin

We use gravitational lensing to study the small-scale distribution of matter in galaxies. First, we examine galaxies and their dark matter halos. Roughly half of all observed four-image quasar lenses have image flux ratios that differ from the values predicted by simple lens potentials. We show that smooth departures from elliptical symmetry fail to explain anomalous radio fluxes, strengthening the case for dark matter substructure. Our results have important implications for the "missing satellites'' problem. We then consider how time delays between lensed images can be used to identify lens galaxies containing small-scale structure. We derive an analytic relation for the time delay between the close pair of images in a "fold'' lens, and perform Monte Carlo simulations to investigate the utility of time delays for probing small- scale structure in realistic lens populations. We compare our numerical predictions with systems that have measured time delays and discover two anomalous lenses. Next, we consider microlensing, where stars in the lens galaxy perturb image magnifications. This is relevant at optical wavelengths, where the size of the lensed source is comparable to the Einstein radius of a typical star. Our simulations of negative-parity images show that raising the fraction of dark matter relative to stars increases image flux variability for small sources, and decreases it for large sources. This suggests that quasar accretion disks and broad-emission-line regions may respond differently to microlensing. We also consider extended sources with a range of ellipticities, which has relevance to a population of inclined accretion disks. Depending on their orientation, more elongated sources lead to more rapid variability, which may complicate the interpretation of microlensing light curves. Finally, we consider prospects for observing strong lensing by the supermassive black hole at the center of the Milky Way, Sgr A*. Assuming a black hole on the million- solar-mass scale, we predict that the probability of observing strong lensing of a background star is roughly 56%. We also consider how lensing by Sgr A* could be used to test general relativity against alternative theories, concluding that microarcsecond resolution would make this possible.
Gravitational self-force meets the post-Newtonian approximation in extreme-mass ratio inspiral of binary black holes

NASA Astrophysics Data System (ADS)

Detweiler, Steven

2010-02-01

Post-Newtonian analysis, numerical relativity and, now, perturbation-based gravitational self-force analysis are all being used to describe various aspects of black hole binary systems. Recent comparisons between self-force analysis, with m1m2, and post-Newtonian analysis, with v/c 1 show excellent agreement in their common domain of validity. This lends credence to the two very different regularization procedures which are invoked in these approximations. When self-force analysis is able to create gravitational waveforms from extreme mass-ratio inspiral, then unprecedented cross cultural comparisons of these three distinct approaches to understanding gravitational waves will reveal the strengths and weaknesses of each. )
Matching Matched Filtering with Deep Networks for Gravitational-Wave Astronomy

NASA Astrophysics Data System (ADS)

Gabbard, Hunter; Williams, Michael; Hayes, Fergus; Messenger, Chris

2018-04-01

We report on the construction of a deep convolutional neural network that can reproduce the sensitivity of a matched-filtering search for binary black hole gravitational-wave signals. The standard method for the detection of well-modeled transient gravitational-wave signals is matched filtering. We use only whitened time series of measured gravitational-wave strain as an input, and we train and test on simulated binary black hole signals in synthetic Gaussian noise representative of Advanced LIGO sensitivity. We show that our network can classify signal from noise with a performance that emulates that of match filtering applied to the same data sets when considering the sensitivity defined by receiver-operator characteristics.

Matching Matched Filtering with Deep Networks for Gravitational-Wave Astronomy.

PubMed

Gabbard, Hunter; Williams, Michael; Hayes, Fergus; Messenger, Chris

2018-04-06

We report on the construction of a deep convolutional neural network that can reproduce the sensitivity of a matched-filtering search for binary black hole gravitational-wave signals. The standard method for the detection of well-modeled transient gravitational-wave signals is matched filtering. We use only whitened time series of measured gravitational-wave strain as an input, and we train and test on simulated binary black hole signals in synthetic Gaussian noise representative of Advanced LIGO sensitivity. We show that our network can classify signal from noise with a performance that emulates that of match filtering applied to the same data sets when considering the sensitivity defined by receiver-operator characteristics.
Observing the dynamics of supermassive black hole binaries with pulsar timing arrays.

PubMed

Mingarelli, C M F; Grover, K; Sidery, T; Smith, R J E; Vecchio, A

2012-08-24

Pulsar timing arrays are a prime tool to study unexplored astrophysical regimes with gravitational waves. Here, we show that the detection of gravitational radiation from individually resolvable supermassive black hole binary systems can yield direct information about the masses and spins of the black holes, provided that the gravitational-wave-induced timing fluctuations both at the pulsar and at Earth are detected. This in turn provides a map of the nonlinear dynamics of the gravitational field and a new avenue to tackle open problems in astrophysics connected to the formation and evolution of supermassive black holes. We discuss the potential, the challenges, and the limitations of these observations.
The Optical Gravitational Lensing Experiment. BVI Maps of Dense Stellar Regions. III. The Galactic Bulge

NASA Astrophysics Data System (ADS)

Udalski, A.; Szymanski, M.; Kubiak, M.; Pietrzynski, G.; Soszynski, I.; Wozniak, P.; Zebrun, K.; Szewczyk, O.; Wyrzykowski, L.

2002-09-01

We present the VI photometric maps of the Galactic bulge. They contain VI photometry and astrometry of about 30 million stars from 49 fields of 0.225 square degree each in the Galactic center region. The data were collected during the second phase of the OGLE microlensing project. We discuss the accuracy of data and present color-magnitude diagrams of selected fields observed by OGLE in the Galactic bulge. The VI maps of the Galactic bulge are accessible electronically for the astronomical community from the OGLE Internet archive.
Results of the GstLAL Search for Compact Binary Mergers in Advanced LIGO's First Observing Run

NASA Astrophysics Data System (ADS)

Lang, Ryan; LIGO Scientific Collaboration; Virgo Collaboration Collaboration

2017-01-01

Advanced LIGO's first observing period ended in January 2016. We discuss the GstLAL matched-filter search over this data set for gravitational waves from compact binary objects with total mass up to 100 solar masses. In particular, we discuss the recovery of the unambiguous gravitational wave signals GW150914 and GW151226, as well as the possible third signal LVT151012. Additionally, we discuss the constraints we can place on binary-neutron-star and neutron-star-black-hole system merger rates.
Effects of Neutron-Star Dynamic Tides on Gravitational Waveforms within the Effective-One-Body Approach

NASA Astrophysics Data System (ADS)

Hinderer, Tanja; Taracchini, Andrea; Foucart, Francois; Buonanno, Alessandra; Steinhoff, Jan; Duez, Matthew; Kidder, Lawrence E.; Pfeiffer, Harald P.; Scheel, Mark A.; Szilagyi, Bela; Hotokezaka, Kenta; Kyutoku, Koutarou; Shibata, Masaru; Carpenter, Cory W.

2016-05-01

Extracting the unique information on ultradense nuclear matter from the gravitational waves emitted by merging neutron-star binaries requires robust theoretical models of the signal. We develop a novel effective-one-body waveform model that includes, for the first time, dynamic (instead of only adiabatic) tides of the neutron star as well as the merger signal for neutron-star-black-hole binaries. We demonstrate the importance of the dynamic tides by comparing our model against new numerical-relativity simulations of nonspinning neutron-star-black-hole binaries spanning more than 24 gravitational-wave cycles, and to other existing numerical simulations for double neutron-star systems. Furthermore, we derive an effective description that makes explicit the dependence of matter effects on two key parameters: tidal deformability and fundamental oscillation frequency.
Effects of Neutron-Star Dynamic Tides on Gravitational Waveforms within the Effective-One-Body Approach.

PubMed

Hinderer, Tanja; Taracchini, Andrea; Foucart, Francois; Buonanno, Alessandra; Steinhoff, Jan; Duez, Matthew; Kidder, Lawrence E; Pfeiffer, Harald P; Scheel, Mark A; Szilagyi, Bela; Hotokezaka, Kenta; Kyutoku, Koutarou; Shibata, Masaru; Carpenter, Cory W

2016-05-06

Extracting the unique information on ultradense nuclear matter from the gravitational waves emitted by merging neutron-star binaries requires robust theoretical models of the signal. We develop a novel effective-one-body waveform model that includes, for the first time, dynamic (instead of only adiabatic) tides of the neutron star as well as the merger signal for neutron-star-black-hole binaries. We demonstrate the importance of the dynamic tides by comparing our model against new numerical-relativity simulations of nonspinning neutron-star-black-hole binaries spanning more than 24 gravitational-wave cycles, and to other existing numerical simulations for double neutron-star systems. Furthermore, we derive an effective description that makes explicit the dependence of matter effects on two key parameters: tidal deformability and fundamental oscillation frequency.
Matter effects on LIGO/Virgo searches for gravitational waves from merging neutron stars

NASA Astrophysics Data System (ADS)

Cullen, Torrey; Harry, Ian; Read, Jocelyn; Flynn, Eric

2017-12-01

Gravitational waves from merging neutron stars are expected to be observed in the next five years. We explore the potential impact of matter effects on gravitational waves from merging double neutron-star binaries. If neutron star binaries exist with chirp masses less than roughly one solar mass and typical neutron-star radii are larger than roughly 14 km, or if neutron-star radii are larger than 15-16 km for the chirp masses of galactic neutron-star binaries, then matter will have a significant impact on the effectiveness of a point-particle-based search at Advanced LIGO design sensitivity (roughly 5% additional loss of signals). In a configuration typical of LIGO’s first observing run, extreme matter effects lead to up to 10% potential loss in the most extreme cases.
Gravitational-Wave Tests of General Relativity with Ground-Based Detectors and Pulsar-Timing Arrays.

PubMed

Yunes, Nicolás; Siemens, Xavier

2013-01-01

This review is focused on tests of Einstein's theory of general relativity with gravitational waves that are detectable by ground-based interferometers and pulsar-timing experiments. Einstein's theory has been greatly constrained in the quasi-linear, quasi-stationary regime, where gravity is weak and velocities are small. Gravitational waves will allow us to probe a complimentary, yet previously unexplored regime: the non-linear and dynamical strong-field regime . Such a regime is, for example, applicable to compact binaries coalescing, where characteristic velocities can reach fifty percent the speed of light and gravitational fields are large and dynamical. This review begins with the theoretical basis and the predicted gravitational-wave observables of modified gravity theories. The review continues with a brief description of the detectors, including both gravitational-wave interferometers and pulsar-timing arrays, leading to a discussion of the data analysis formalism that is applicable for such tests. The review ends with a discussion of gravitational-wave tests for compact binary systems.
Gravitational Waveforms in the Early Inspiral of Binary Black Hole Systems

NASA Astrophysics Data System (ADS)

Barkett, Kevin; Kumar, Prayush; Bhagwat, Swetha; Brown, Duncan; Scheel, Mark; Szilagyi, Bela; Simulating eXtreme Spacetimes Collaboration

2015-04-01

The inspiral, merger and ringdown of compact object binaries are important targets for gravitational wave detection by aLIGO. Detection and parameter estimation will require long, accurate waveforms for comparison. There are a number of analytical models for generating gravitational waveforms for these systems, but the only way to ensure their consistency and correctness is by comparing with numerical relativity simulations that cover many inspiral orbits. We've simulated a number of binary black hole systems with mass ratio 7 and a moderate, aligned spin on the larger black hole. We have attached these numerical waveforms to analytical waveform models to generate long hybrid gravitational waveforms that span the entire aLIGO frequency band. We analyze the robustness of these hybrid waveforms and measure the faithfulness of different hybrids with each other to obtain an estimate on how long future numerical simulations need to be in order to ensure that waveforms are accurate enough for use by aLIGO.
Black-hole kicks from numerical-relativity surrogate models

NASA Astrophysics Data System (ADS)

Gerosa, Davide; Hébert, François; Stein, Leo C.

2018-05-01

Binary black holes radiate linear momentum in gravitational waves as they merge. Recoils imparted to the black-hole remnant can reach thousands of km /s , thus ejecting black holes from their host galaxies. We exploit recent advances in gravitational waveform modeling to quickly and reliably extract recoils imparted to generic, precessing, black-hole binaries. Our procedure uses a numerical-relativity surrogate model to obtain the gravitational waveform given a set of binary parameters; then, from this waveform we directly integrate the gravitational-wave linear momentum flux. This entirely bypasses the need for fitting formulas which are typically used to model black-hole recoils in astrophysical contexts. We provide a thorough exploration of the black-hole kick phenomenology in the parameter space, summarizing and extending previous numerical results on the topic. Our extraction procedure is made publicly available as a module for the Python programming language named surrkick. Kick evaluations take ˜0.1 s on a standard off-the-shelf machine, thus making our code ideal to be ported to large-scale astrophysical studies.
Observing gravitational-wave transient GW150914 with minimal assumptions

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackburn, L.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chatterji, S.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Clark, M.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; DeRosa, R. T.; De Rosa, R.; DeSalvo, R.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gatto, A.; Gaur, G.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Haas, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hinder, I.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, C.; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinsey, M.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Laguna, P.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Logue, J.; Lombardi, A. L.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Page, J.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Phelps, M.; Piccinni, O.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2016-06-01

The gravitational-wave signal GW150914 was first identified on September 14, 2015, by searches for short-duration gravitational-wave transients. These searches identify time-correlated transients in multiple detectors with minimal assumptions about the signal morphology, allowing them to be sensitive to gravitational waves emitted by a wide range of sources including binary black hole mergers. Over the observational period from September 12 to October 20, 2015, these transient searches were sensitive to binary black hole mergers similar to GW150914 to an average distance of ˜600 Mpc . In this paper, we describe the analyses that first detected GW150914 as well as the parameter estimation and waveform reconstruction techniques that initially identified GW150914 as the merger of two black holes. We find that the reconstructed waveform is consistent with the signal from a binary black hole merger with a chirp mass of ˜30 M⊙ and a total mass before merger of ˜70 M⊙ in the detector frame.
Binary Black Holes, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Centrella, John

2007-01-01

The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GE0600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, data analysis, and astrophysics.
Black-Hole Binaries, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Kelly, Bernard J.; Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.

2010-01-01

Understanding the predictions of general relativity for the dynamical interactions of two black holes has been a long-standing unsolved problem in theoretical physics. Black-hole mergers are monumental astrophysical events ' releasing tremendous amounts of energy in the form of gravitational radiation ' and are key sources for both ground- and spacebased gravitational wave detectors. The black-hole merger dynamics and the resulting gravitational waveforms can only he calculated through numerical simulations of Einstein's equations of general relativity. For many years, numerical relativists attempting to model these mergers encountered a host of problems, causing their codes to crash after just a fraction of a binary orbit cnuld be simulated. Recently ' however, a series of dramatic advances in numerical relativity has ' for the first time, allowed stable / robust black hole merger simulations. We chronicle this remarkable progress in the rapidly maturing field of numerical relativity, and the new understanding of black-hole binary dynamics that is emerging. We also discuss important applications of these fundamental physics results to astrophysics, to gravitationalwave astronomy, and in other areas.
The formation and gravitational-wave detection of massive stellar black hole binaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belczynski, Krzysztof; Walczak, Marek; Buonanno, Alessandra

2014-07-10

If binaries consisting of two ∼100 M{sub ☉} black holes exist, they would serve as extraordinarily powerful gravitational-wave sources, detectable to redshifts of z ∼ 2 with the advanced LIGO/Virgo ground-based detectors. Large uncertainties about the evolution of massive stars preclude definitive rate predictions for mergers of these massive black holes. We show that rates as high as hundreds of detections per year, or as low as no detections whatsoever, are both possible. It was thought that the only way to produce these massive binaries was via dynamical interactions in dense stellar systems. This view has been challenged by themore » recent discovery of several ≳ 150 M{sub ☉} stars in the R136 region of the Large Magellanic Cloud. Current models predict that when stars of this mass leave the main sequence, their expansion is insufficient to allow common envelope evolution to efficiently reduce the orbital separation. The resulting black hole-black hole binary remains too wide to be able to coalesce within a Hubble time. If this assessment is correct, isolated very massive binaries do not evolve to be gravitational-wave sources. However, other formation channels exist. For example, the high multiplicity of massive stars, and their common formation in relatively dense stellar associations, opens up dynamical channels for massive black hole mergers (e.g., via Kozai cycles or repeated binary-single interactions). We identify key physical factors that shape the population of very massive black hole-black hole binaries. Advanced gravitational-wave detectors will provide important constraints on the formation and evolution of very massive stars.« less
HYPERCRITICAL ACCRETION, INDUCED GRAVITATIONAL COLLAPSE, AND BINARY-DRIVEN HYPERNOVAE

DOE PAGES

Fryer, Chris L.; Rueda, Jorge A.; Ruffini, Remo

2014-09-16

We successfully, applied the induced gravitational collapse (IGC) paradigm to the explanation of GRB-SNe. The progenitor is a tight binary system composed of a CO core and a NS companion. Furthermore, the explosion of the SN leads to hypercritical accretion onto the NS companion, which reaches the critical mass, gravitationally collapsing to a BH with consequent emission of the GRB. The first estimates of this process were based on a simplified model of the binary parameters and the Bondi-Hoyle-Lyttleton accretion rate. We present the first full numerical simulations of the IGC process. We simulate the core-collapse, the SN explosion, andmore » the hydrodynamic evolution of the accreting material falling into the Bondi-Hoyle surface of the NS. For appropriate binary parameters, the IGC occurs in short timescale 102–103 s due to the combined action of photon trapping and neutrino cooling near the NS surface. We also address the observational features of this process.« less
Detecting gravity waves from binary black holes

NASA Technical Reports Server (NTRS)

Wahlquist, Hugo D.

1989-01-01

One of the most attractive possible sources of strong gravitational waves would be a binary system comprising massive black holes (BH). The gravitational radiation from a binary is an elliptically polarized, periodic wave which could be observed continuously - or at intervals whenever a detector was available. This continuity of the signal is certainly appealing compared to waiting for individual pulses from infrequent random events. It also has the advantage over pulses that continued observation can increase the signal-to-noise ratio almost indefinitely. Furthermore, this system is dynamically simple; the theory of the generation of the radiation is unambiguous; all characteristics of the signal can be precisely related to the dynamical parameters of the source. The current situation is that while there is no observational evidence as yet for the existence of massive binary BH, their formation is theoretically plausible, and within certain coupled constraints of mass and location, their existence cannot be observationally excluded. Detecting gravitational waves from these objects might be the first observational proof of their existence.
Einstein's Gift: Stellar Mass Black Holes in the LIGO Era

NASA Astrophysics Data System (ADS)

Cadonati, Laura; Georgia Institute of Technology, LIGO-Virgo Collaboration

2017-01-01

The discovery of gravitational waves from the coalescence of black hole binary systems in LIGO has provided the first evidence for heavy stellar mass black holes. In this talk, I will review the observational evidence for black holes in LIGO data, its astrophysical implications and the plans for the near and long term future of ground based gravitational wave detection of black hole binary coalescences.
surrkick: Black-hole kicks from numerical-relativity surrogate models

NASA Astrophysics Data System (ADS)

Gerosa, Davide; Hébert, François; Stein, Leo C.

2018-04-01

surrkick quickly and reliably extract recoils imparted to generic, precessing, black hole binaries. It uses a numerical-relativity surrogate model to obtain the gravitational waveform given a set of binary parameters, and from this waveform directly integrates the gravitational-wave linear momentum flux. This entirely bypasses the need of fitting formulae which are typically used to model black-hole recoils in astrophysical contexts.
Primordial black holes—perspectives in gravitational wave astronomy

NASA Astrophysics Data System (ADS)

Sasaki, Misao; Suyama, Teruaki; Tanaka, Takahiro; Yokoyama, Shuichiro

2018-03-01

This article reviews current understanding of primordial black holes (PBHs), with particular focus on those massive examples (≳ 1015~g ) which remain at the present epoch, not having evaporated through Hawking radiation. With the detection of gravitational waves by LIGO, we have gained a completely novel observational tool to search for PBHs, complementary to those using electromagnetic waves. Taking the perspective that gravitational-wave astronomy will make significant progress in the coming decades, the purpose of this article is to give a comprehensive review covering a wide range of topics on PBHs. After discussing PBH formation, as well as several inflation models leading to PBH production, we summarize various existing and future observational constraints. We then present topics on formation of PBH binaries, gravitational waves from PBH binaries, and various observational tests of PBHs using gravitational waves.
Distinguishing black-hole spin-orbit resonances by their gravitational-wave signatures

NASA Astrophysics Data System (ADS)

Gerosa, Davide; O'Shaughnessy, Richard; Kesden, Michael; Berti, Emanuele; Sperhake, Ulrich

2014-06-01

If binary black holes form following the successive core collapses of sufficiently massive binary stars, precessional dynamics may align their spins, Smathvariant="bold">1 and Smathvariant="bold">2, and the orbital angular momentum L into a plane in which they jointly precess about the total angular momentum J. These spin orientations are known as spin-orbit resonances since S1, S2, and L all precess at the same frequency to maintain their planar configuration. Two families of such spin-orbit resonances exist, differentiated by whether the components of the two spins in the orbital plane are either aligned or antialigned. The fraction of binary black holes in each family is determined by the stellar evolution of their progenitors, so if gravitational-wave detectors could measure this fraction they could provide important insights into astrophysical formation scenarios for binary black holes. In this paper, we show that even under the conservative assumption that binary black holes are observed along the direction of J (where precession-induced modulations to the gravitational waveforms are minimized), the waveforms of many members of each resonant family can be distinguished from all members of the other family in events with signal-to-noise ratios ρ ≃10, typical of those expected for the first detections with Advanced LIGO and Virgo. We hope that our preliminary findings inspire a greater appreciation of the capability of gravitational-wave detectors to constrain stellar astrophysics and stimulate further studies of the distinguishability of spin-orbit resonant families in more expanded regions of binary black-hole parameter space.

Getting a Kick Out of Numerical Relativity

NASA Technical Reports Server (NTRS)

2006-01-01

Operating ground-based gravitational wave detectors and a planned instrument in space are bringing about the new field of gravitational wave astronomy. A prime source for any of these observatories is the merger of a system of two black holes. Brought together by copious losses of gravitational-wave energy, these systems merge in a burst of energy with a peak power exceeding any electromagnetic source. Observations of these sources will generate a wealth of astrophysical information, and may provide an unparalleled probe of strong-field gravitational physics, but a full interpretation of the observations will require detailed predictions from General Relativity. I will discuss recent advances in numerical simulations of binary black hole systems which are generating dramatic progress in understanding binary black hole mergers. Recent achievements include the first simulations of binary black hole systems through several orbits and merger, leading to detailed predictions for the final portion of the gravitational radiation waveforms from equal-mass mergers. For unequal-mass mergers, it has recently become possible to measure the impulsive kick imparted to the final black hole, by the asymmetry of the merger radiation. These first results announce an accelerating wave of progress soon to come from the energetic field of numerical relativity.
Speeding up low-mass planetary microlensing simulations and modeling: The caustic region of influence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Penny, Matthew T., E-mail: penny@astronomy.ohio-state.edu

2014-08-01

Extensive simulations of planetary microlensing are necessary both before and after a survey is conducted: before to design and optimize the survey and after to understand its detection efficiency. The major bottleneck in such computations is the computation of light curves. However, for low-mass planets, most of these computations are wasteful, as most light curves do not contain detectable planetary signatures. In this paper, I develop a parameterization of the binary microlens that is conducive to avoiding light curve computations. I empirically find analytic expressions describing the limits of the parameter space that contain the vast majority of low-mass planetmore » detections. Through a large-scale simulation, I measure the (in)completeness of the parameterization and the speed-up it is possible to achieve. For Earth-mass planets in a wide range of orbits, it is possible to speed up simulations by a factor of ∼30-125 (depending on the survey's annual duty-cycle) at the cost of missing ∼1% of detections (which is actually a smaller loss than for the arbitrary parameter limits typically applied in microlensing simulations). The benefits of the parameterization probably outweigh the costs for planets below 100 M{sub ⊕}. For planets at the sensitivity limit of AFTA-WFIRST, simulation speed-ups of a factor ∼1000 or more are possible.« less
Binary black holes, gravitational waves, and numerical relativity

NASA Astrophysics Data System (ADS)

Centrella, Joan M.; Baker, John G.; Boggs, William D.; Kelly, Bernard J.; McWilliams, Sean T.; van Meter, James R.

2007-07-01

The final merger of comparable mass binary black holes produces an intense burst of gravitational radiation and is one of the strongest sources for both ground-based and space-based gravitational wave detectors. Since the merger occurs in the strong-field dynamical regime of general relativity, numerical relativity simulations of the full Einstein equations in 3-D are required to calculate the resulting gravitational dynamics and waveforms. While this problem has been pursued for more than 30 years, the numerical codes have long been plagued by various instabilities and, overall, progress was incremental. Recently, however, dramatic breakthrough have occurred, resulting in robust simulations of merging black holes. In this paper, we examine these developments and the exciting new results that are emerging.
Binary Black Hole Mergers in the First Advanced LIGO Observing Run

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Bejger, M.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fenyvesi, E.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fong, H.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gaebel, S.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gehrels, N.; Gemme, G.; Geng, P.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hamilton, H.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jian, L.; Jiménez-Forteza, F.; Johnson, W. W.; Johnson-McDaniel, N. K.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chi-Woong; Kim, Chunglee; Kim, J.; Kim, K.; Kim, N.; Kim, W.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Lewis, J. B.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C.; Lück, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Nedkova, K.; Nelemans, G.; Nelson, T. J. N.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pan, Y.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Porter, E.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O. E. S.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Setyawati, Y.; Shaddock, D. A.; Shaffer, T.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stevenson, S.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tomlinson, C.; Tonelli, M.; Tornasi, Z.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2016-10-01

The first observational run of the Advanced LIGO detectors, from September 12, 2015 to January 19, 2016, saw the first detections of gravitational waves from binary black hole mergers. In this paper, we present full results from a search for binary black hole merger signals with total masses up to 100 M⊙ and detailed implications from our observations of these systems. Our search, based on general-relativistic models of gravitational-wave signals from binary black hole systems, unambiguously identified two signals, GW150914 and GW151226, with a significance of greater than 5 σ over the observing period. It also identified a third possible signal, LVT151012, with substantially lower significance and with an 87% probability of being of astrophysical origin. We provide detailed estimates of the parameters of the observed systems. Both GW150914 and GW151226 provide an unprecedented opportunity to study the two-body motion of a compact-object binary in the large velocity, highly nonlinear regime. We do not observe any deviations from general relativity, and we place improved empirical bounds on several high-order post-Newtonian coefficients. From our observations, we infer stellar-mass binary black hole merger rates lying in the range 9 - 240 Gpc-3 yr-1 . These observations are beginning to inform astrophysical predictions of binary black hole formation rates and indicate that future observing runs of the Advanced detector network will yield many more gravitational-wave detections.
Gravitational Wave Astrophysics in the Mid-band: progenitors and advanced localizations of Advanced LIGO/Virgo binary-merger events

NASA Astrophysics Data System (ADS)

Cheung, Chi C. Teddy; Hogan, Jason; Graham, Peter; Kasevich, Mark; Rajendran, Surjeet; Saif, Babak; Kerr, Matthew T.; Lovellette, Michael; Wood, Kent S.; Michelson, Peter; MAGIS Team

2018-01-01

We consider the scientific potential of gravitational wave (GW) observations in the ~30 mHz to 3 Hz frequency range with the Mid-band Atomic Gravitational-wave Interferometric Sensor (MAGIS). MAGIS is a probe-class space-mission concept, using an atom-based gravitational wave detector, that will provide all-sky strain sensitivities of ~10^-21 sqrt(Hz) and better (1-year) in the GW-frequency mid-band between the LISA/L3 detector (planned 2034 launch) and ground-based Advanced LIGO/Virgo interferometers. Primary gravitational wave astrophysics science in the mid-band include GW observations of the binary black hole population discovered by Advanced LIGO/Virgo at higher-frequencies, prior to their merger stage. For such systems, MAGIS will observe the binaries in their inspiral phase, where system parameters such as eccentricities are most easily constrained, and will provide advanced, degree-scale localizations that would enable electromagnetic observations of possible precursor emission 1-week to 1-month prior to their mergers as well as prompt post-merger transient emission. Joint GW-observations with MAGIS and Advanced LIGO/Virgo covering all stages of binary coalescence will further reduce uncertainties in the GW- localizations and distances, and will be powerful paired with galaxy catalogs, to enable unique galaxy counterpart identifications in the case black hole binary mergers are completely absent of detectable electromagnetic precursor or transient signals. These possibilities for MAGIS extend to neutron star binary systems (black hole - neutron star, neutron star - neutron star), and mid-band prospects for such systems will also be considered.The MAGIS team is a collaboration between institutes in the U.S. including Stanford, AOSense, Harvard, NASA/GSFC, NASA/JPL, NIST, NRL, and UC Berkeley, and international partners at Birmingham, Bordeaux, CNRS, Dusseldorf, Ecole Normale Superieure, Florence, Hannover, and Ulm University.
Gravitational wave searches for aligned-spin binary neutron stars using nonspinning templates

NASA Astrophysics Data System (ADS)

Cho, Hee-Suk; Lee, Chang-Hwan

2018-01-01

We study gravitational wave searches for merging binary neutron stars (NSs). We use nonspinning template waveforms towards the signals emitted from aligned-spin NS-NS binaries, in which the spins of the NSs are aligned with the orbital angular momentum. We use the TaylorF2 waveform model, which can generate inspiral waveforms emitted from aligned-spin compact binaries. We employ the single effective spin parameter χeff to represent the effect of two component spins (χ1, χ2) on the wave function. For a target system, we choose a binary consisting of the same component masses of 1.4 M ⊙ and consider the spins up to χ i = 0.4. We investigate fitting factors of the nonspinning templates to evaluate their efficiency in gravitational wave searches for the aligned-spin NS-NS binaries. We find that the templates can achieve the fitting factors exceeding 0.97 only for the signals in the range of -0.2 ≲ χeff ≲ 0. Therefore, we demonstrate the necessity of using aligned-spin templates not to lose the signals outside that range. We also show how much the recovered total mass can be biased from the true value depending on the spin of the signal.
Detectability of gravitational waves from binary black holes: Impact of precession and higher modes

NASA Astrophysics Data System (ADS)

Calderón Bustillo, Juan; Laguna, Pablo; Shoemaker, Deirdre

2017-05-01

Gravitational wave templates used in current searches for binary black holes omit the effects of precession of the orbital plane and higher-order modes. While this omission seems not to impact the detection of sources having mass ratios and spins similar to those of GW150914, even for total masses M >200 M⊙ , we show that it can cause large fractional losses of sensitive volume for binaries with mass ratio q ≥4 and M >100 M⊙, measured in the detector frame. For the highest precessing cases, this is true even when the source is face-on to the detector. Quantitatively, we show that the aforementioned omission can lead to fractional losses of sensitive volume of ˜15 %, reaching >25 % for the worst cases studied. Loss estimates are obtained by evaluating the effectualness of the SEOBNRv2-ROM double spin model, currently used in binary black hole searches, towards gravitational wave signals from precessing binaries computed by means of numerical relativity. We conclude that, for sources with q ≥4 , a reliable search for binary black holes heavier than M >100 M⊙ needs to consider the effects of higher-order modes and precession. The latter seems especially necessary when Advanced LIGO reaches its design sensitivity.
Dynamical Formation Signatures of Black Hole Binaries in the First Detected Mergers by LIGO

NASA Astrophysics Data System (ADS)

O'Leary, Ryan M.; Meiron, Yohai; Kocsis, Bence

2016-06-01

The dynamical formation of stellar-mass black hole-black hole binaries has long been a promising source of gravitational waves for the Laser Interferometer Gravitational-Wave Observatory (LIGO). Mass segregation, gravitational focusing, and multibody dynamical interactions naturally increase the interaction rate between the most massive black holes in dense stellar systems, eventually leading them to merge. We find that dynamical interactions, particularly three-body binary formation, enhance the merger rate of black hole binaries with total mass M tot roughly as \\propto {M}{{tot}}β , with β ≳ 4. We find that this relation holds mostly independently of the initial mass function, but the exact value depends on the degree of mass segregation. The detection rate of such massive black hole binaries is only further enhanced by LIGO’s greater sensitivity to massive black hole binaries with M tot ≲ 80 {M}⊙ . We find that for power-law BH mass functions dN/dM ∝ M -α with α ≤ 2, LIGO is most likely to detect black hole binaries with a mass twice that of the maximum initial black hole mass and a mass ratio near one. Repeated mergers of black holes inside the cluster result in about ˜5% of mergers being observed between two and three times the maximum initial black hole mass. Using these relations, one may be able to invert the observed distribution to the initial mass function with multiple detections of merging black hole binaries.
Massive Black-Hole Binary Mergers: Dynamics, Environments & Expected Detections

NASA Astrophysics Data System (ADS)

Kelley, Luke Zoltan

2018-05-01

This thesis studies the populations and dynamics of massive black-hole binaries and their mergers, and explores the implications for electromagnetic and gravitational-wave signals that will be detected in the near future. Massive black-holes (MBH) reside in the centers of galaxies, and when galaxies merge, their MBH interact and often pair together. We base our study on the populations of MBH and galaxies from the `Illustris' cosmological hydrodynamic simulations. The bulk of the binary merger dynamics, however, are unresolved in cosmological simulations. We implement a suite of comprehensive physical models for the merger process, like dynamical friction and gravitational wave emission, which are added in post-processing. Contrary to many previous studies, we find that the most massive binaries with near equal-mass companions are the most efficient at coalescing; though the process still typically takes gigayears.From the data produced by these MBH binary populations and their dynamics, we calculate the expected gravitational wave (GW) signals: both the stochastic, GW background of countless unresolved sources, and the GW foreground of individually resolvable binaries which resound above the noise. Ongoing experiments, called pulsar timing arrays, are sensitive to both of these types of signals. We find that, while the current lack of detections is unsurprising, both the background and foreground will plausibly be detected in the next decade. Unlike previous studies which have predicted the foreground to be significantly harder to detect than the background, we find their typical amplitudes are comparable.With traditional electromagnetic observations, there has also been a dearth of confirmed detections of MBH binary systems. We use our binaries, combined with models of emission from accreting MBH systems, to make predictions for the occurrence rate of systems observable using photometric, periodic-variability surveys. These variables should be detectable in current surveys, and indeed, we expect many candidates recently identified to be true binaries - though a significant fraction are likely false positives. Overall, this thesis finds the science of MBH binaries at an exciting cusp: just before incredible breakthroughs in observations, both electromagnetically and in the new age of gravitational wave astrophysics.
Sensitivity of gravitational wave searches to the full signal of intermediate-mass black hole binaries during the first observing run of Advanced LIGO

NASA Astrophysics Data System (ADS)

Calderón Bustillo, Juan; Salemi, Francesco; Dal Canton, Tito; Jani, Karan P.

2018-01-01

The sensitivity of gravitational wave searches for binary black holes is estimated via the injection and posterior recovery of simulated gravitational wave signals in the detector data streams. When a search reports no detections, the estimated sensitivity is then used to place upper limits on the coalescence rate of the target source. In order to obtain correct sensitivity and rate estimates, the injected waveforms must be faithful representations of the real signals. Up to date, however, injected waveforms have neglected radiation modes of order higher than the quadrupole, potentially biasing sensitivity and coalescence rate estimates. In particular, higher-order modes are known to have a large impact in the gravitational waves emitted by intermediate-mass black holes binaries. In this work, we evaluate the impact of this approximation in the context of two search algorithms run by the LIGO Scientific Collaboration in their search for intermediate-mass black hole binaries in the O1 LIGO Science Run data: a matched filter-based pipeline and a coherent unmodeled one. To this end, we estimate the sensitivity of both searches to simulated signals for nonspinning binaries including and omitting higher-order modes. We find that omission of higher-order modes leads to biases in the sensitivity estimates which depend on the masses of the binary, the search algorithm, and the required level of significance for detection. In addition, we compare the sensitivity of the two search algorithms across the studied parameter space. We conclude that the most recent LIGO-Virgo upper limits on the rate of coalescence of intermediate-mass black hole binaries are conservative for the case of highly asymmetric binaries. However, the tightest upper limits, placed for nearly equal-mass sources, remain unchanged due to the small contribution of higher modes to the corresponding sources.
GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Afrough, M.; Agarwal, B.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allen, G.; Allocca, A.; Altin, P. A.; Amato, A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Angelova, S. V.; Antier, S.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Atallah, D. V.; Aufmuth, P.; Aulbert, C.; AultONeal, K.; Austin, C.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Bae, S.; Bailes, M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Banagiri, S.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barkett, K.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Barthelmy, S. D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bawaj, M.; Bayley, J. C.; Bazzan, M.; Bécsy, B.; Beer, C.; Bejger, M.; Belahcene, I.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Bernuzzi, S.; Bero, J. J.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Biscoveanu, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackman, J.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bode, N.; Boer, M.; Bogaert, G.; Bohe, A.; Bondu, F.; Bonilla, E.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bossie, K.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T. A.; Calloni, E.; Camp, J. B.; Canepa, M.; Canizares, P.; Cannon, K. C.; Cao, H.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Carney, M. F.; Carullo, G.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerdá-Durán, P.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chase, E.; Chassande-Mottin, E.; Chatterjee, D.; Chatziioannou, K.; Cheeseboro, B. D.; Chen, H. Y.; Chen, X.; Chen, Y.; Cheng, H.-P.; Chia, H.; Chincarini, A.; Chiummo, A.; Chmiel, T.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, A. J. K.; Chua, S.; Chung, A. K. W.; Chung, S.; Ciani, G.; Ciolfi, R.; Cirelli, C. E.; Cirone, A.; Clara, F.; Clark, J. A.; Clearwater, P.; Cleva, F.; Cocchieri, C.; Coccia, E.; Cohadon, P.-F.; Cohen, D.; Colla, A.; Collette, C. G.; Cominsky, L. R.; Constancio, M.; Conti, L.; Cooper, S. J.; Corban, P.; Corbitt, T. R.; Cordero-Carrión, I.; Corley, K. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Covas, P. B.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cullen, T. J.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Dálya, G.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davis, D.; Daw, E. J.; Day, B.; De, S.; DeBra, D.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Demos, N.; Denker, T.; Dent, T.; De Pietri, R.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; De Rossi, C.; DeSalvo, R.; de Varona, O.; Devenson, J.; Dhurandhar, S.; Díaz, M. C.; Dietrich, T.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Renzo, F.; Doctor, Z.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dorrington, I.; Douglas, R.; Dovale Álvarez, M.; Downes, T. P.; Drago, M.; Dreissigacker, C.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dudi, R.; Dupej, P.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Eisenstein, R. A.; Essick, R. C.; Estevez, D.; Etienne, Z. B.; Etzel, T.; Evans, M.; Evans, T. M.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E. J.; Favata, M.; Fays, M.; Fee, C.; Fehrmann, H.; Feicht, J.; Fejer, M. M.; Fernandez-Galiana, A.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Finstad, D.; Fiori, I.; Fiorucci, D.; Fishbach, M.; Fisher, R. P.; Fitz-Axen, M.; Flaminio, R.; Fletcher, M.; Fong, H.; Font, J. A.; Forsyth, P. W. F.; Forsyth, S. S.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fries, E. M.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H.; Gadre, B. U.; Gaebel, S. M.; Gair, J. R.; Gammaitoni, L.; Ganija, M. R.; Gaonkar, S. G.; Garcia-Quiros, C.; Garufi, F.; Gateley, B.; Gaudio, S.; Gaur, G.; Gayathri, V.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, D.; George, J.; Gergely, L.; Germain, V.; Ghonge, S.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glover, L.; Goetz, E.; Goetz, R.; Gomes, S.; Goncharov, B.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Gretarsson, E. M.; Groot, P.; Grote, H.; Grunewald, S.; Gruning, P.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Halim, O.; Hall, B. R.; Hall, E. D.; Hamilton, E. Z.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hannuksela, O. A.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hinderer, T.; Ho, W. C. G.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Horst, C.; Hough, J.; Houston, E. A.; Howell, E. J.; Hreibi, A.; Hu, Y. M.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Inta, R.; Intini, G.; Isa, H. N.; Isac, J.-M.; Isi, M.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Johnson-McDaniel, N. K.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Junker, J.; Kalaghatgi, C. V.; Kalogera, V.; Kamai, B.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Kastaun, W.; Katolik, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kawabe, K.; Kéfélian, F.; Keitel, D.; Kemball, A. J.; Kennedy, R.; Kent, C.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J. C.; Kim, K.; Kim, W.; Kim, W. S.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kinley-Hanlon, M.; Kirchhoff, R.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Knowles, T. D.; Koch, P.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Krämer, C.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, P.; Kumar, R.; Kumar, S.; Kuo, L.; Kutynia, A.; Kwang, S.; Lackey, B. D.; Lai, K. H.; Landry, M.; Lang, R. N.; Lange, J.; Lantz, B.; Lanza, R. K.; Larson, S. L.; Lartaux-Vollard, A.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, H. W.; Lee, K.; Lehmann, J.; Lenon, A.; Leon, E.; Leonardi, M.; Leroy, N.; Letendre, N.; Levin, Y.; Li, T. G. F.; Linker, S. D.; Littenberg, T. B.; Liu, J.; Liu, X.; Lo, R. K. L.; Lockerbie, N. A.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C. O.; Lovelace, G.; Lück, H.; Lumaca, D.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macas, R.; Macfoy, S.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña Hernandez, I.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markakis, C.; Markosyan, A. S.; Markowitz, A.; Maros, E.; Marquina, A.; Marsh, P.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Massera, E.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matas, A.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McCuller, L.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McNeill, L.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Mejuto-Villa, E.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, B. B.; Miller, J.; Millhouse, M.; Milovich-Goff, M. C.; Minazzoli, O.; Minenkov, Y.; Ming, J.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moffa, D.; Moggi, A.; Mogushi, K.; Mohan, M.; Mohapatra, S. R. P.; Molina, I.; Montani, M.; Moore, C. J.; Moraru, D.; Moreno, G.; Morisaki, S.; Morriss, S. R.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Muñiz, E. A.; Muratore, M.; Murray, P. G.; Nagar, A.; Napier, K.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Neilson, J.; Nelemans, G.; Nelson, T. J. N.; Nery, M.; Neunzert, A.; Nevin, L.; Newport, J. M.; Newton, G.; Ng, K. K. Y.; Nguyen, P.; Nguyen, T. T.; Nichols, D.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Noack, A.; Nocera, F.; Nolting, D.; North, C.; Nuttall, L. K.; Oberling, J.; O'Dea, G. D.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Okada, M. A.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; Ormiston, R.; Ortega, L. F.; O'Shaughnessy, R.; Ossokine, S.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pace, A. E.; Page, J.; Page, M. A.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, Howard; Pan, Huang-Wei; Pang, B.; Pang, P. T. H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Parida, A.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patil, M.; Patricelli, B.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perez, C. J.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pirello, M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Porter, E. K.; Post, A.; Powell, J.; Prasad, J.; Pratt, J. W. W.; Pratten, G.; Predoi, V.; Prestegard, T.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rajbhandari, B.; Rakhmanov, M.; Ramirez, K. E.; Ramos-Buades, A.; Rapagnani, P.; Raymond, V.; Razzano, M.; Read, J.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Ren, W.; Reyes, S. D.; Ricci, F.; Ricker, P. M.; Rieger, S.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romel, C. L.; Romie, J. H.; Rosińska, D.; Ross, M. P.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Rutins, G.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sampson, L. M.; Sanchez, E. J.; Sanchez, L. E.; Sanchis-Gual, N.; Sandberg, V.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Scheel, M.; Scheuer, J.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schulte, B. W.; Schutz, B. F.; Schwalbe, S. G.; Scott, J.; Scott, S. M.; Seidel, E.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D. A.; Shaffer, T. J.; Shah, A. A.; Shahriar, M. S.; Shaner, M. B.; Shao, L.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, L. P.; Singh, A.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, B.; Smith, J. R.; Smith, R. J. E.; Somala, S.; Son, E. J.; Sonnenberg, J. A.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Spencer, A. P.; Srivastava, A. K.; Staats, K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stevenson, S. P.; Stone, R.; Stops, D. J.; Strain, K. A.; Stratta, G.; Strigin, S. E.; Strunk, A.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Suresh, J.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Tait, S. C.; Talbot, C.; Talukder, D.; Tanner, D. B.; Tápai, M.; Taracchini, A.; Tasson, J. D.; Taylor, J. A.; Taylor, R.; Tewari, S. V.; Theeg, T.; Thies, F.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tonelli, M.; Tornasi, Z.; Torres-Forné, A.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trinastic, J.; Tringali, M. C.; Trozzo, L.; Tsang, K. W.; Tse, M.; Tso, R.; Tsukada, L.; Tsuna, D.; Tuyenbayev, D.; Ueno, K.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Varma, V.; Vass, S.; Vasúth, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Venugopalan, G.; Verkindt, D.; Vetrano, F.; Viceré, A.; Viets, A. D.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walet, R.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, J. Z.; Wang, W. H.; Wang, Y. F.; Ward, R. L.; Warner, J.; Was, M.; Watchi, J.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessel, E. K.; Weßels, P.; Westerweck, J.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; Whiting, B. F.; Whittle, C.; Wilken, D.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Wofford, J.; Wong, K. W. K.; Worden, J.; Wright, J. L.; Wu, D. S.; Wysocki, D. M.; Xiao, S.; Yamamoto, H.; Yancey, C. C.; Yang, L.; Yap, M. J.; Yazback, M.; Yu, Hang; Yu, Haocun; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zelenova, T.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, T.; Zhang, Y.-H.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, S. J.; Zhu, X. J.; Zimmerman, A. B.; Zucker, M. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2017-10-01

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0 ×104 years . We infer the component masses of the binary to be between 0.86 and 2.26 M⊙ , in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17 - 1.60 M⊙ , with the total mass of the system 2.7 4-0.01+0.04M⊙ . The source was localized within a sky region of 28 deg2 (90% probability) and had a luminosity distance of 4 0-14+8 Mpc , the closest and most precisely localized gravitational-wave signal yet. The association with the γ -ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ -ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.
1974: the discovery of the first binary pulsar

NASA Astrophysics Data System (ADS)

Damour, Thibault

2015-06-01

The 1974 discovery, by Russell A Hulse and Joseph H Taylor, of the first binary pulsar, PSR B1913+16, opened up new possibilities for the study of relativistic gravity. PSR B1913+16, as well as several other binary pulsars, provided direct observational proof that gravity propagates at the velocity of light and has a quadrupolar structure. Binary pulsars also provided accurate tests of the strong-field regime of relativistic gravity. General relativity has passed all of the binary pulsar tests with flying colors. The discovery of binary pulsars also had very important consequences for astrophysics, leading to accurate measurement of neutron star masses, improved understanding of the possible evolution scenarios for the co-evolution of binary stars, and proof of the existence of binary neutron stars emitting gravitational waves for hundreds of millions of years, before coalescing in catastrophic events radiating intense gravitational wave signals, and probably also leading to important emissions of electromagnetic radiation and neutrinos. This article reviews the history of the discovery of the first binary pulsar, and describes both its immediate impact and its longer-term effect on theoretical and experimental studies of relativistic gravity.
Bi-lobed Shape of Comet 67P from a Collapsed Binary

NASA Astrophysics Data System (ADS)

Nesvorný, David; Parker, Joel; Vokrouhlický, David

2018-06-01

The Rosetta spacecraft observations revealed that the nucleus of comet 67P/Churyumov–Gerasimenko consists of two similarly sized lobes connected by a narrow neck. Here, we evaluate the possibility that 67P is a collapsed binary. We assume that the progenitor of 67P was a binary and consider various physical mechanisms that could have brought the binary components together, including small-scale impacts and gravitational encounters with planets. We find that 67P could be a primordial body (i.e., not a collisional fragment) if the outer planetesimal disk lasted ≲10 Myr before it was dispersed by migrating Neptune. The probability of binary collapse by impact is ≃30% for tightly bound binaries. Most km-class binaries become collisionally dissolved. Roughly 10% of the surviving binaries later evolve to become contact binaries during the disk dispersal, when bodies suffer gravitational encounters with Neptune. Overall, the processes described in this work do not seem to be efficient enough to explain the large fraction (∼67%) of bi-lobed cometary nuclei inferred from spacecraft imaging.
Parameter Estimation for Compact Binaries with Ground-Based Gravitational-Wave Observations Using the LALInference

NASA Technical Reports Server (NTRS)

Veitch, J.; Raymond, V.; Farr, B.; Farr, W.; Graff, P.; Vitale, S.; Aylott, B.; Blackburn, K.; Christensen, N.; Coughlin, M.

2015-01-01

The Advanced LIGO and Advanced Virgo gravitational wave (GW) detectors will begin operation in the coming years, with compact binary coalescence events a likely source for the first detections. The gravitational waveforms emitted directly encode information about the sources, including the masses and spins of the compact objects. Recovering the physical parameters of the sources from the GW observations is a key analysis task. This work describes the LALInference software library for Bayesian parameter estimation of compact binary signals, which builds on several previous methods to provide a well-tested toolkit which has already been used for several studies. We show that our implementation is able to correctly recover the parameters of compact binary signals from simulated data from the advanced GW detectors. We demonstrate this with a detailed comparison on three compact binary systems: a binary neutron star (BNS), a neutron star - black hole binary (NSBH) and a binary black hole (BBH), where we show a cross-comparison of results obtained using three independent sampling algorithms. These systems were analysed with non-spinning, aligned spin and generic spin configurations respectively, showing that consistent results can be obtained even with the full 15-dimensional parameter space of the generic spin configurations. We also demonstrate statistically that the Bayesian credible intervals we recover correspond to frequentist confidence intervals under correct prior assumptions by analysing a set of 100 signals drawn from the prior. We discuss the computational cost of these algorithms, and describe the general and problem-specific sampling techniques we have used to improve the efficiency of sampling the compact binary coalescence (CBC) parameter space.
Extreme gravity tests with gravitational waves from compact binary coalescences: (II) ringdown

NASA Astrophysics Data System (ADS)

Berti, Emanuele; Yagi, Kent; Yang, Huan; Yunes, Nicolás

2018-05-01

The LIGO/Virgo detections of binary black hole mergers marked a watershed moment in astronomy, ushering in the era of precision tests of Kerr dynamics. We review theoretical and experimental challenges that must be overcome to carry out black hole spectroscopy with present and future gravitational wave detectors. Among other topics, we discuss quasinormal mode excitation in binary mergers, astrophysical event rates, tests of black hole dynamics in modified theories of gravity, parameterized "post-Kerr" ringdown tests, exotic compact objects, and proposed data analysis methods to improve spectroscopic tests of Kerr dynamics by stacking multiple events.
Characterizing Black Hole Mergers

NASA Technical Reports Server (NTRS)

Baker, John; Boggs, William Darian; Kelly, Bernard

2010-01-01

Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.
Accuracy of Estimating Highly Eccentric Binary Black Hole Parameters with Gravitational-wave Detections

NASA Astrophysics Data System (ADS)

Gondán, László; Kocsis, Bence; Raffai, Péter; Frei, Zsolt

2018-03-01

Mergers of stellar-mass black holes on highly eccentric orbits are among the targets for ground-based gravitational-wave detectors, including LIGO, VIRGO, and KAGRA. These sources may commonly form through gravitational-wave emission in high-velocity dispersion systems or through the secular Kozai–Lidov mechanism in triple systems. Gravitational waves carry information about the binaries’ orbital parameters and source location. Using the Fisher matrix technique, we determine the measurement accuracy with which the LIGO–VIRGO–KAGRA network could measure the source parameters of eccentric binaries using a matched filtering search of the repeated burst and eccentric inspiral phases of the waveform. We account for general relativistic precession and the evolution of the orbital eccentricity and frequency during the inspiral. We find that the signal-to-noise ratio and the parameter measurement accuracy may be significantly higher for eccentric sources than for circular sources. This increase is sensitive to the initial pericenter distance, the initial eccentricity, and the component masses. For instance, compared to a 30 {M}ȯ –30 {M}ȯ non-spinning circular binary, the chirp mass and sky-localization accuracy can improve by a factor of ∼129 (38) and ∼2 (11) for an initially highly eccentric binary assuming an initial pericenter distance of 20 M tot (10 M tot).
Bayesian model-emulation of stochastic gravitational-wave spectra for probes of the final-parsec problem with pulsar-timing arrays

NASA Astrophysics Data System (ADS)

Taylor, Stephen R.; Simon, Joseph; Sampson, Laura

2017-01-01

The final parsec of supermassive black-hole binary evolution is subject to the complex interplay of stellar loss-cone scattering, circumbinary disk accretion, and gravitational-wave emission, with binary eccentricity affected by all of these. The strain spectrum of gravitational-waves in the pulsar-timing band thus encodes rich information about the binary population's response to these various environmental mechanisms. Current spectral models have heretofore followed basic analytic prescriptions, and attempt to investigate these final-parsec mechanisms in an indirect fashion. Here we describe a new technique to directly probe the environmental properties of supermassive black-hole binaries through "Bayesian model-emulation". We perform black-hole binary population synthesis simulations at a restricted set of environmental parameter combinations, compute the strain spectra from these, then train a Gaussian process to learn the shape of the spectrum at any point in parameter space. We describe this technique, demonstrate its efficacy with a program of simulated datasets, then illustrate its power by directly constraining final-parsec physics in a Bayesian analysis of the NANOGrav 5-year dataset. The technique is fast, flexible, and robust.
Bayesian model-emulation of stochastic gravitational-wave spectra for probes of the final-parsec problem with pulsar-timing arrays

NASA Astrophysics Data System (ADS)

Taylor, Stephen; Simon, Joseph; Sampson, Laura

2017-01-01

The final parsec of supermassive black-hole binary evolution is subject to the complex interplay of stellar loss-cone scattering, circumbinary disk accretion, and gravitational-wave emission, with binary eccentricity affected by all of these. The strain spectrum of gravitational-waves in the pulsar-timing band thus encodes rich information about the binary population's response to these various environmental mechanisms. Current spectral models have heretofore followed basic analytic prescriptions, and attempt to investigate these final-parsec mechanisms in an indirect fashion. Here we describe a new technique to directly probe the environmental properties of supermassive black-hole binaries through ``Bayesian model-emulation''. We perform black-hole binary population synthesis simulations at a restricted set of environmental parameter combinations, compute the strain spectra from these, then train a Gaussian process to learn the shape of spectrum at any point in parameter space. We describe this technique, demonstrate its efficacy with a program of simulated datasets, then illustrate its power by directly constraining final-parsec physics in a Bayesian analysis of the NANOGrav 5-year dataset. The technique is fast, flexible, and robust.
Discovery of the First Quadruple Gravitationally Lensed Quasar Candidate with Pan-STARRS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berghea, C. T.; Nelson, George J.; Dudik, R. P.

We report the serendipitous discovery of the first gravitationally lensed quasar candidate from Pan-STARRS. The grizy images reveal four point-like images with magnitudes between 14.9 and 18.1 mag. The colors of the point sources are similar, and they are more consistent with quasars than with stars or galaxies. The lensing galaxy is detected in the izy bands, with an inferred photometric redshift of ∼0.6, lower than that of the point sources. We successfully model the system with a singular isothermal ellipsoid with shear, using the relative positions of the five objects as constraints. While the brightness ranking of the pointmore » sources is consistent with that of the model, we find discrepancies between the model-predicted and observed fluxes, likely due to microlensing by stars and millilensing due to the dark matter substructure. In order to fully confirm the gravitational lens nature of this system and add it to the small but growing number of the powerful probes of cosmology and astrophysics represented by quadruply lensed quasars, we require further spectroscopy and high-resolution imaging.« less

Possible role of magnetic reconnection in the electromagnetic counterpart of binary black hole merger

NASA Astrophysics Data System (ADS)

Fraschetti, F.

2018-04-01

We propose a qualitative scenario to interpret the argued association between the direct measurement of the gravitational wave event GW150914 by Laser Interferometer Gravitational Wave Observatory (LIGO)-Virgo collaborations and the hard X-ray transient detected by Fermi-Gamma-ray Burst Monitor (GBM) 0.4 sec after. In a binary system of two gravitationally collapsing objects with a non-vanishing electric charge, the compenetration of the two magnetospheres occurring during the coalescence, through magnetic reconnection, produces a highly collimated relativistic outflow that becomes optically thin and shines in the GBM field of view. We propose that this process should be expected as a commonplace in the future joint gravitational/electromagnetic detections and, in case of neutron star-neutron star merger event, might lead to detectable X- or γ-ray precursors to, or transients associated with, the gravitational bursts.
Black Hole Kicks as New Gravitational Wave Observables.

PubMed

Gerosa, Davide; Moore, Christopher J

2016-07-01

Generic black hole binaries radiate gravitational waves anisotropically, imparting a recoil, or kick, velocity to the merger remnant. If a component of the kick along the line of sight is present, gravitational waves emitted during the final orbits and merger will be gradually Doppler shifted as the kick builds up. We develop a simple prescription to capture this effect in existing waveform models, showing that future gravitational wave experiments will be able to perform direct measurements, not only of the black hole kick velocity, but also of its accumulation profile. In particular, the eLISA space mission will measure supermassive black hole kick velocities as low as ∼500 km s^{-1}, which are expected to be a common outcome of black hole binary coalescence following galaxy mergers. Black hole kicks thus constitute a promising new observable in the growing field of gravitational wave astronomy.
Observation of Gravitational Waves from a Binary Black Hole Merger

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Arain, M. A.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Belczynski, C.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Bustillo, J. Calderón; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Baiardi, L. Cerboni; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cruise, A. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; DeRosa, R. T.; De Rosa, R.; DeSalvo, R.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fong, H.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gatto, A.; Gaur, G.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Gleason, J. R.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Castro, J. M. Gonzalez; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Greenhalgh, R. J. S.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heefner, J.; Heidmann, A.; Heintze, M. C.; Heinzel, G.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacobson, M. B.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Johnson-McDaniel, N. K.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Keppel, D. G.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, C.; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Koranda, S.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Kwee, P.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Logue, J.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C. O.; Lovelace, G.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pan, Y.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J. H.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Ramet, C. R.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sampson, L. M.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, G. H.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shaffer, T.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, M. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stevenson, S. P.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Waldman, S. J.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, H.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Willems, P. A.; Williams, L.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yakushin, I.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2016-02-01

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 ×10-21. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1 σ . The source lies at a luminosity distance of 41 0-180+160 Mpc corresponding to a redshift z =0.0 9-0.04+0.03 . In the source frame, the initial black hole masses are 3 6-4+5M⊙ and 2 9-4+4M⊙ , and the final black hole mass is 6 2-4+4M⊙ , with 3. 0-0.5+0.5M⊙ c2 radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.
Observation of Gravitational Waves from a Binary Black Hole Merger

NASA Technical Reports Server (NTRS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Camp, Jordan B.;

2016-01-01

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 x 10(exp -21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ring down of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1 Sigma. The source lies at a luminosity distance of 410(+160/-180) Mpc corresponding to a redshift z = 0.09(+0.03/-0.04). In the source frame, the initial black hole masses are 36(+5/-4) Mass compared to the sun, and 29(+4/-4) Mass compared to the sun, and the final black hole mass is 62(+4/-4) Mass compared to the sun, with 3.0(+0.5/-0.5)sq c radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.

Observation of Gravitational Waves from a Binary Black Hole Merger.

PubMed

Abbott, B P; Abbott, R; Abbott, T D; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V B; Affeldt, C; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Aiello, L; Ain, A; Ajith, P; Allen, B; Allocca, A; Altin, P A; Anderson, S B; Anderson, W G; Arai, K; Arain, M A; Araya, M C; Arceneaux, C C; Areeda, J S; Arnaud, N; Arun, K G; Ascenzi, S; Ashton, G; Ast, M; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Babak, S; Bacon, P; Bader, M K M; Baker, P T; Baldaccini, F; Ballardin, G; Ballmer, S W; Barayoga, J C; Barclay, S E; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barta, D; Bartlett, J; Barton, M A; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Baune, C; Bavigadda, V; Bazzan, M; Behnke, B; Bejger, M; Belczynski, C; Bell, A S; Bell, C J; Berger, B K; Bergman, J; Bergmann, G; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Birch, J; Birney, R; Birnholtz, O; Biscans, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blair, C D; Blair, D G; Blair, R M; Bloemen, S; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bogan, C; Bohe, A; Bojtos, P; Bond, C; Bondu, F; Bonnand, R; Boom, B A; Bork, R; Boschi, V; Bose, S; Bouffanais, Y; Bozzi, A; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Brillet, A; Brinkmann, M; Brisson, V; Brockill, P; Brooks, A F; Brown, D A; Brown, D D; Brown, N M; Buchanan, C C; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Byer, R L; Cabero, M; Cadonati, L; Cagnoli, G; Cahillane, C; Calderón Bustillo, J; Callister, T; Calloni, E; Camp, J B; Cannon, K C; Cao, J; Capano, C D; Capocasa, E; Carbognani, F; Caride, S; Casanueva Diaz, J; Casentini, C; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C B; Cerboni Baiardi, L; Cerretani, G; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chan, M; Chao, S; Charlton, P; Chassande-Mottin, E; 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2016-02-12

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160) Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.
Gravitational radiation as a test of relativistic gravity

NASA Technical Reports Server (NTRS)

Will, Clifford M.

1989-01-01

Gravitational radiation can be used to test theories of gravitation. When the waves are ultimately detected directly, their speed and polarization properties can be measured and compared with predictions of alternative theories. The multipole nature of gravitational radiation was already tested in the binary pulsar, where observations of the decay of the orbit verify the quadrupole formula for gravitational radiation damping of general relativity and put strong constraints on dipole gravitational radiation predicted by many alternative theories.
Caustics of 1/r{sup n} binary gravitational lenses: from galactic haloes to exotic matter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bozza, V.; Melchiorre, C., E-mail: valboz@physics.unisa.it, E-mail: cmelchiorre@unisa.it

2016-03-01

We investigate the caustic topologies for binary gravitational lenses made up of two objects whose gravitational potential declines as 1/r{sup n}. With n<1 this corresponds to power-law dust distributions like the singular isothermal sphere. The n>1 regime can be obtained with some violations of the energy conditions, one famous example being the Ellis wormhole. Gravitational lensing provides a natural arena to distinguish and identify such exotic objects in our Universe. We find that there are still three topologies for caustics as in the standard Schwarzschild binary lens, with the main novelty coming from the secondary caustics of the close topology,more » which become huge at higher n. After drawing caustics by numerical methods, we derive a large amount of analytical formulae in all limits that are useful to provide deeper insight in the mathematics of the problem. Our study is useful to better understand the phenomenology of galaxy lensing in clusters as well as the distinct signatures of exotic matter in complex systems.« less
Sensitivity of the Advanced LIGO detectors at the beginning of gravitational wave astronomy

NASA Astrophysics Data System (ADS)

Martynov, D. V.; Hall, E. D.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Adams, C.; Adhikari, R. X.; Anderson, R. A.; Anderson, S. B.; Arai, K.; Arain, M. A.; Aston, S. M.; Austin, L.; Ballmer, S. W.; Barbet, M.; Barker, D.; Barr, B.; Barsotti, L.; Bartlett, J.; Barton, M. A.; Bartos, I.; Batch, J. C.; Bell, A. S.; Belopolski, I.; Bergman, J.; Betzwieser, J.; Billingsley, G.; Birch, J.; Biscans, S.; Biwer, C.; Black, E.; Blair, C. D.; Bogan, C.; Bork, R.; Bridges, D. O.; Brooks, A. F.; Celerier, C.; Ciani, G.; Clara, F.; Cook, D.; Countryman, S. T.; Cowart, M. J.; Coyne, D. C.; Cumming, A.; Cunningham, L.; Damjanic, M.; Dannenberg, R.; Danzmann, K.; Costa, C. F. Da Silva; Daw, E. J.; DeBra, D.; DeRosa, R. T.; DeSalvo, R.; Dooley, K. L.; Doravari, S.; Driggers, J. C.; Dwyer, S. E.; Effler, A.; Etzel, T.; Evans, M.; Evans, T. M.; Factourovich, M.; Fair, H.; Feldbaum, D.; Fisher, R. P.; Foley, S.; Frede, M.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Galdi, V.; Giaime, J. A.; Giardina, K. D.; Gleason, J. R.; Goetz, R.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Grote, H.; Guido, C. J.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hammond, G.; Hanks, J.; Hanson, J.; Hardwick, T.; Harry, G. M.; Heefner, J.; Heintze, M. C.; Heptonstall, A. W.; Hoak, D.; Hough, J.; Ivanov, A.; Izumi, K.; Jacobson, M.; James, E.; Jones, R.; Kandhasamy, S.; Karki, S.; Kasprzack, M.; Kaufer, S.; Kawabe, K.; Kells, W.; Kijbunchoo, N.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kokeyama, K.; Korth, W. Z.; Kuehn, G.; Kwee, P.; Landry, M.; Lantz, B.; Le Roux, A.; Levine, B. M.; Lewis, J. B.; Lhuillier, V.; Lockerbie, N. A.; Lormand, M.; Lubinski, M. J.; Lundgren, A. P.; MacDonald, T.; MacInnis, M.; Macleod, D. M.; Mageswaran, M.; Mailand, K.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Massinger, T. J.; Matichard, F.; Mavalvala, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McIntyre, G.; McIver, J.; Merilh, E. L.; Meyer, M. S.; Meyers, P. M.; Miller, J.; Mittleman, R.; Moreno, G.; Mueller, C. L.; Mueller, G.; Mullavey, A.; Munch, J.; Nuttall, L. K.; Oberling, J.; O'Dell, J.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; Osthelder, C.; Ottaway, D. J.; Overmier, H.; Palamos, J. R.; Paris, H. R.; Parker, W.; Patrick, Z.; Pele, A.; Penn, S.; Phelps, M.; Pickenpack, M.; Pierro, V.; Pinto, I.; Poeld, J.; Principe, M.; Prokhorov, L.; Puncken, O.; Quetschke, V.; Quintero, E. A.; Raab, F. J.; Radkins, H.; Raffai, P.; Ramet, C. R.; Reed, C. M.; Reid, S.; Reitze, D. H.; Robertson, N. A.; Rollins, J. G.; Roma, V. J.; Romie, J. H.; Rowan, S.; Ryan, K.; Sadecki, T.; Sanchez, E. J.; Sandberg, V.; Sannibale, V.; Savage, R. L.; Schofield, R. M. S.; Schultz, B.; Schwinberg, P.; Sellers, D.; Sevigny, A.; Shaddock, D. A.; Shao, Z.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sigg, D.; Slagmolen, B. J. J.; Smith, J. R.; Smith, M. R.; Smith-Lefebvre, N. D.; Sorazu, B.; Staley, A.; Stein, A. J.; Stochino, A.; Strain, K. A.; Taylor, R.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Torrie, C. I.; Traylor, G.; Vajente, G.; Valdes, G.; van Veggel, A. A.; Vargas, M.; Vecchio, A.; Veitch, P. J.; Venkateswara, K.; Vo, T.; Vorvick, C.; Waldman, S. J.; Walker, M.; Ward, R. L.; Warner, J.; Weaver, B.; Weiss, R.; Welborn, T.; Weßels, P.; Wilkinson, C.; Willems, P. A.; Williams, L.; Willke, B.; Winkelmann, L.; Wipf, C. C.; Worden, J.; Wu, G.; Yamamoto, H.; Yancey, C. C.; Yu, H.; Zhang, L.; Zucker, M. E.; Zweizig, J.

2016-06-01

The Laser Interferometer Gravitational Wave Observatory (LIGO) consists of two widely separated 4 km laser interferometers designed to detect gravitational waves from distant astrophysical sources in the frequency range from 10 Hz to 10 kHz. The first observation run of the Advanced LIGO detectors started in September 2015 and ended in January 2016. A strain sensitivity of better than 10-23/√{Hz } was achieved around 100 Hz. Understanding both the fundamental and the technical noise sources was critical for increasing the astrophysical strain sensitivity. The average distance at which coalescing binary black hole systems with individual masses of 30 M⊙ could be detected above a signal-to-noise ratio (SNR) of 8 was 1.3 Gpc, and the range for binary neutron star inspirals was about 75 Mpc. With respect to the initial detectors, the observable volume of the Universe increased by a factor 69 and 43, respectively. These improvements helped Advanced LIGO to detect the gravitational wave signal from the binary black hole coalescence, known as GW150914.
Probing the size of extra dimensions with gravitational wave astronomy

NASA Astrophysics Data System (ADS)

Yagi, Kent; Tanahashi, Norihiro; Tanaka, Takahiro

2011-04-01

In the Randall-Sundrum II braneworld model, it has been conjectured, according to the AdS/CFT correspondence, that a brane-localized black hole (BH) larger than the bulk AdS curvature scale ℓ cannot be static, and it is dual to a four-dimensional BH emitting Hawking radiation through some quantum fields. In this scenario, the number of the quantum field species is so large that this radiation changes the orbital evolution of a BH binary. We derived the correction to the gravitational waveform phase due to this effect and estimated the upper bounds on ℓ by performing Fisher analyses. We found that the Deci-Hertz Interferometer Gravitational Wave Observatory and the Big Bang Observatory (DECIGO/BBO) can give a stronger constraint than the current tabletop result by detecting gravitational waves from small mass BH/BH and BH/neutron star (NS) binaries. Furthermore, DECIGO/BBO is expected to detect 105 BH/NS binaries per year. Taking this advantage, we find that DECIGO/BBO can actually measure ℓ down to ℓ=0.33μm for a 5 yr observation if we know that binaries are circular a priori. This is about 40 times smaller than the upper bound obtained from the tabletop experiment. On the other hand, when we take eccentricities into binary parameters, the detection limit weakens to ℓ=1.5μm due to strong degeneracies between ℓ and eccentricities. We also derived the upper bound on ℓ from the expected detection number of extreme mass ratio inspirals with LISA and BH/NS binaries with DECIGO/BBO, extending the discussion made recently by McWilliams [Phys. Rev. Lett. 104, 141601 (2010)PRLTAO0031-900710.1103/PhysRevLett.104.141601]. We found that these less robust constraints are weaker than the ones from phase differences.
Visualizing, Approximating, and Understanding Black-Hole Binaries

NASA Astrophysics Data System (ADS)

Nichols, David A.

Numerical-relativity simulations of black-hole binaries and advancements in gravitational-wave detectors now make it possible to learn more about the collisions of compact astrophysical bodies. To be able to infer more about the dynamical behavior of these objects requires a fuller analysis of the connection between the dynamics of pairs of black holes and their emitted gravitational waves. The chapters of this thesis describe three approaches to learn more about the relationship between the dynamics of black-hole binaries and their gravitational waves: modeling momentum flow in binaries with the Landau-Lifshitz formalism, approximating binary dynamics near the time of merger with post-Newtonian and black-hole-perturbation theories, and visualizing spacetime curvature with tidal tendexes and frame-drag vortexes. In Chapters 2--4, my collaborators and I present a method to quantify the flow of momentum in black-hole binaries using the Landau-Lifshitz formalism. Chapter 2 reviews an intuitive version of the formalism in the first-post-Newtonian approximation that bears a strong resemblance to Maxwell's theory of electromagnetism. Chapter 3 applies this approximation to relate the simultaneous bobbing motion of rotating black holes in the superkick configuration---equal-mass black holes with their spins anti-aligned and in the orbital plane---to the flow of momentum in the spacetime, prior to the black holes' merger. Chapter 4 then uses the Landau-Lifshitz formalism to explain the dynamics of a head-on merger of spinning black holes, whose spins are anti-aligned and transverse to the infalling motion. Before they merge, the black holes move with a large, transverse, velocity, which we can explain using the post-Newtonian approximation; as the holes merge and form a single black hole, we can use the Landau-Lifshitz formalism without any approximations to connect the slowing of the final black hole to its absorbing momentum density during the merger. In Chapters 5--7, we discuss using analytical approximations, such as post-Newtonian and black-hole-perturbation theories, to gain further understanding into how gravitational waves are generated by black-hole binaries. Chapter 5 presents a way of combining post-Newtonian and black-hole-perturbation theories---which we call the hybrid method---for head-on mergers of black holes. It was able to produce gravitational waveforms and gravitational recoils that agreed well with comparable results from numerical-relativity simulations. Chapter 6 discusses a development of the hybrid model to include a radiation-reaction force, which is better suited for studying inspiralling black-hole binaries. The gravitational waveform from the hybrid method for inspiralling mergers agreed qualitatively with that from numerical-relativity simulations; when applied to the superkick configuration, it gave a simplified picture of the formation of the large black-hole kick. Chapter 7 describes an approximate method of calculating the frequencies of the ringdown gravitational waveforms of rotating black holes (quasinormal modes). The method generalizes a geometric interpretation of black-hole quasinormal modes and explains a degeneracy in the spectrum of these modes. In Chapters 8--11, we describe a new way of visualizing spacetime curvature using tools called tidal tendexes and frame-drag vortexes. This relies upon a time-space split of spacetime, which allows one to break the vacuum Riemann curvature tensor into electric and magnetic parts (symmetric, trace-free tensors that have simple physical interpretations). The regions where the eigenvalues of these tensors are large form the tendexes and vortexes of a spacetime, and the integral curves of their eigenvectors are its tendex and vortex lines, for the electric and magnetic parts, respectively. Chapter 8 provides an overview of these visualization tools and presents initial results from numerical-relativity simulations. Chapter 9 uses topological properties of vortex and tendex lines to classify properties of gravitational waves far from a source. Chapter 10 describes the formalism in more detail, and discusses the vortexes and tendexes of multipolar spacetimes in linearized gravity about flat space. The chapter helps to explain how near-zone vortexes and tendexes become gravitational waves far from a weakly gravitating, time-varying source. Chapter 11 is a detailed investigation of the vortexes and tendexes of stationary and perturbed black holes. It develops insight into how perturbations of (strongly gravitating) black holes extend from near the horizon to become gravitational waves.
Electromagnetic radiation accompanying gravitational waves from black hole binaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dolgov, A.; Postnov, K., E-mail: dolgov@fe.infn.it, E-mail: kpostnov@gmail.com

The transition of powerful gravitational waves, created by the coalescence of massive black hole binaries, into electromagnetic radiation in external magnetic fields is considered. In contrast to the previous calculations of the similar effect we study the realistic case of the gravitational radiation frequency below the plasma frequency of the surrounding medium. The gravitational waves propagating in the plasma constantly create electromagnetic radiation dragging it with them, despite the low frequency. The plasma heating by the unattenuated electromagnetic wave may be significant in hot rarefied plasma with strong magnetic field and can lead to a noticeable burst of electromagnetic radiationmore » with higher frequency. The graviton-to-photon conversion effect in plasma is discussed in the context of possible electromagnetic counterparts of GW150914 and GW170104.« less
The Final Merger of Black-Hole Binaries

NASA Technical Reports Server (NTRS)

Kelly, Bernard J.; Centrealla, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.

2010-01-01

Recent breakthroughs in the field of numerical relativity have led to dramatic progress in understanding the predictions of General Relativity for the dynamical interactions of two black holes in the regime of very strong gravitational fields. Such black-hole binaries are important astrophysical systems and are a key target of current and developing gravitational-wave detectors. The waveform signature of strong gravitational radiation emitted as the black holes fall together and merge provides a clear observable record of the process. After decades of slow progress / these mergers and the gravitational-wave signals they generate can now be routinely calculated using the methods of numerical relativity. We review recent advances in understanding the predicted physics of events and the consequent radiation, and discuss some of the impacts this new knowledge is having in various areas of astrophysics
Recent searches for continuous gravitational waves

NASA Astrophysics Data System (ADS)

Riles, Keith

2017-12-01

Gravitational wave astronomy opened dramatically in September 2015 with the LIGO discovery of a distant and massive binary black hole coalescence. The more recent discovery of a binary neutron star merger, followed by a gamma ray burst (GRB) and a kilonova, reinforces the excitement of this new era, in which we may soon see other sources of gravitational waves, including continuous, nearly monochromatic signals. Potential continuous wave (CW) sources include rapidly spinning galactic neutron stars and more exotic possibilities, such as emission from axion Bose Einstein “clouds” surrounding black holes. Recent searches in Advanced LIGO data are presented, and prospects for more sensitive future searches are discussed.
GRAVITATIONAL WAVE EXTRACTION FROM AN INSPIRALING CONFIGURATION OF MERGING BLACK HOLES

NASA Technical Reports Server (NTRS)

Baker, John G.; Centrella, Joan; Dae-Il, Choi; Koppitz, Michael; van Meter, James

2005-01-01

We present new techniques for evolving binary black hole systems which allow the accurate determination of gravitational waveforms directly from the wave zone region of the numerical simulations. Rather than excising the black hole interiors, our approach follows the "puncture" treatment of black holes, but utilizing a new gauge condition which allows the black holes to move successfully through the computational domain. We apply these techniques to an inspiraling binary, modeling the radiation generated during the final plunge and ringdown. We demonstrate convergence of the waveforms and and good conservation of mass-energy, with just over 3% of the system s mass converted to gravitational radiation.
The disruption of multiplanet systems through resonance with a binary orbit.

PubMed

Touma, Jihad R; Sridhar, S

2015-08-27

Most exoplanetary systems in binary stars are of S-type, and consist of one or more planets orbiting a primary star with a wide binary stellar companion. Planetary eccentricities and mutual inclinations can be large, perhaps forced gravitationally by the binary companion. Earlier work on single planet systems appealed to the Kozai-Lidov instability wherein a sufficiently inclined binary orbit excites large-amplitude oscillations in the planet's eccentricity and inclination. The instability, however, can be quenched by many agents that induce fast orbital precession, including mutual gravitational forces in a multiplanet system. Here we report that orbital precession, which inhibits Kozai-Lidov cycling in a multiplanet system, can become fast enough to resonate with the orbital motion of a distant binary companion. Resonant binary forcing results in dramatic outcomes ranging from the excitation of large planetary eccentricities and mutual inclinations to total disruption. Processes such as planetary migration can bring an initially non-resonant system into resonance. As it does not require special physical or initial conditions, binary resonant driving is generic and may have altered the architecture of many multiplanet systems. It can also weaken the multiplanet occurrence rate in wide binaries, and affect planet formation in close binaries.
Gravitational waves: search results, data analysis and parameter estimation: Amaldi 10 Parallel session C2.

PubMed

Astone, Pia; Weinstein, Alan; Agathos, Michalis; Bejger, Michał; Christensen, Nelson; Dent, Thomas; Graff, Philip; Klimenko, Sergey; Mazzolo, Giulio; Nishizawa, Atsushi; Robinet, Florent; Schmidt, Patricia; Smith, Rory; Veitch, John; Wade, Madeline; Aoudia, Sofiane; Bose, Sukanta; Calderon Bustillo, Juan; Canizares, Priscilla; Capano, Colin; Clark, James; Colla, Alberto; Cuoco, Elena; Da Silva Costa, Carlos; Dal Canton, Tito; Evangelista, Edgar; Goetz, Evan; Gupta, Anuradha; Hannam, Mark; Keitel, David; Lackey, Benjamin; Logue, Joshua; Mohapatra, Satyanarayan; Piergiovanni, Francesco; Privitera, Stephen; Prix, Reinhard; Pürrer, Michael; Re, Virginia; Serafinelli, Roberto; Wade, Leslie; Wen, Linqing; Wette, Karl; Whelan, John; Palomba, C; Prodi, G

The Amaldi 10 Parallel Session C2 on gravitational wave (GW) search results, data analysis and parameter estimation included three lively sessions of lectures by 13 presenters, and 34 posters. The talks and posters covered a huge range of material, including results and analysis techniques for ground-based GW detectors, targeting anticipated signals from different astrophysical sources: compact binary inspiral, merger and ringdown; GW bursts from intermediate mass binary black hole mergers, cosmic string cusps, core-collapse supernovae, and other unmodeled sources; continuous waves from spinning neutron stars; and a stochastic GW background. There was considerable emphasis on Bayesian techniques for estimating the parameters of coalescing compact binary systems from the gravitational waveforms extracted from the data from the advanced detector network. This included methods to distinguish deviations of the signals from what is expected in the context of General Relativity.
Angular velocity of gravitational radiation from precessing binaries and the corotating frame

NASA Astrophysics Data System (ADS)

Boyle, Michael

2013-05-01

This paper defines an angular velocity for time-dependent functions on the sphere and applies it to gravitational waveforms from compact binaries. Because it is geometrically meaningful and has a clear physical motivation, the angular velocity is uniquely useful in helping to solve an important—and largely ignored—problem in models of compact binaries: the inverse problem of deducing the physical parameters of a system from the gravitational waves alone. It is also used to define the corotating frame of the waveform. When decomposed in this frame, the waveform has no rotational dynamics and is therefore as slowly evolving as possible. The resulting simplifications lead to straightforward methods for accurately comparing waveforms and constructing hybrids. As formulated in this paper, the methods can be applied robustly to both precessing and nonprecessing waveforms, providing a clear, comprehensive, and consistent framework for waveform analysis. Explicit implementations of all these methods are provided in accompanying computer code.
Gravitational Waves: Search Results, Data Analysis and Parameter Estimation. Amaldi 10 Parallel Session C2

NASA Technical Reports Server (NTRS)

Astone, Pia; Weinstein, Alan; Agathos, Michalis; Bejger, Michal; Christensen, Nelson; Dent, Thomas; Graff, Philip; Klimenko, Sergey; Mazzolo, Giulio; Nishizawa, Atsushi

2015-01-01

The Amaldi 10 Parallel Session C2 on gravitational wave(GW) search results, data analysis and parameter estimation included three lively sessions of lectures by 13 presenters, and 34 posters. The talks and posters covered a huge range of material, including results and analysis techniques for ground-based GW detectors, targeting anticipated signals from different astrophysical sources: compact binary inspiral, merger and ringdown; GW bursts from intermediate mass binary black hole mergers, cosmic string cusps, core-collapse supernovae, and other unmodeled sources; continuous waves from spinning neutron stars; and a stochastic GW background. There was considerable emphasis on Bayesian techniques for estimating the parameters of coalescing compact binary systems from the gravitational waveforms extracted from the data from the advanced detector network. This included methods to distinguish deviations of the signals from what is expected in the context of General Relativity.
Gravitational waves from remnant massive neutron stars of binary neutron star merger: Viscous hydrodynamics effects

NASA Astrophysics Data System (ADS)

Shibata, Masaru; Kiuchi, Kenta

2017-06-01

Employing a simplified version of the Israel-Stewart formalism of general-relativistic shear-viscous hydrodynamics, we explore the evolution of a remnant massive neutron star of binary neutron star merger and pay special attention to the resulting gravitational waveforms. We find that for the plausible values of the so-called viscous alpha parameter of the order 10-2 the degree of the differential rotation in the remnant massive neutron star is significantly reduced in the viscous time scale, ≲5 ms . Associated with this, the degree of nonaxisymmetric deformation is also reduced quickly, and as a consequence, the amplitude of quasiperiodic gravitational waves emitted also decays in the viscous time scale. Our results indicate that for modeling the evolution of the merger remnants of binary neutron stars we would have to take into account magnetohydrodynamics effects, which in nature could provide the viscous effects.
Coincidence probabilities for spacecraft gravitational wave experiments - Massive coalescing binaries

NASA Technical Reports Server (NTRS)

Tinto, Massimo; Armstrong, J. W.

1991-01-01

Massive coalescing binary systems are candidate sources of gravitational radiation in the millihertz frequency band accessible to spacecraft Doppler tracking experiments. This paper discusses signal processing and detection probability for waves from coalescing binaries in the regime where the signal frequency increases linearly with time, i.e., 'chirp' signals. Using known noise statistics, thresholds with given false alarm probabilities are established for one- and two-spacecraft experiments. Given the threshold, the detection probability is calculated as a function of gravitational wave amplitude for both one- and two-spacecraft experiments, assuming random polarization states and under various assumptions about wave directions. This allows quantitative statements about the detection efficiency of these experiments and the utility of coincidence experiments. In particular, coincidence probabilities for two-spacecraft experiments are insensitive to the angle between the directions to the two spacecraft, indicating that near-optical experiments can be done without constraints on spacecraft trajectories.

Gravitational Waves from Stellar Black Hole Binaries and the Impact on Nearby Sun-like Stars

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lopes, Ilídio; Silk, Joseph, E-mail: ilidio.lopes@tecnico.ulisboa.pt, E-mail: silk@astro.ox.ac.uk

We investigate the impact of resonant gravitational waves on quadrupole acoustic modes of Sun-like stars located nearby stellar black hole binary systems (such as GW150914 and GW151226). We find that the stimulation of the low-overtone modes by gravitational radiation can lead to sizeable photometric amplitude variations, much larger than the predictions for amplitudes driven by turbulent convection, which in turn are consistent with the photometric amplitudes observed in most Sun-like stars. For accurate stellar evolution models, using up-to-date stellar physics, we predict photometric amplitude variations of 1–10{sup 3} ppm for a solar mass star located at a distance between 1more » au and 10 au from the black hole binary and belonging to the same multi-star system. The observation of such a phenomenon will be within the reach of the Plato mission because the telescope will observe several portions of the Milky Way, many of which are regions of high stellar density with a substantial mixed population of Sun-like stars and black hole binaries.« less
Binary Black Hole Mergers in the First Advanced LIGO Observing Run

NASA Technical Reports Server (NTRS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, F.; Camp, J. B.;

2016-01-01

The first observational run of the Advanced LIGO detectors, from September 12, 2015 to January 19, 2016, saw the first detections of gravitational waves from binary black hole mergers. In this paper we present full results from a search for binary black hole merger signals with total masses up to 100M solar mass and detailed implications from our observations of these systems. Our search, based on general-relativistic models of gravitational wave signals from binary black hole systems, unambiguously identified two signals, GW150914 and GW151226, with a significance of greater than 5 alpha over the observing period. It also identified a third possible signal, LVT151012, with substantially lower significance, which has a 87 probability of being of astrophysical origin. We provide detailed estimates of the parameters of the observed systems. Both GW150914 and GW151226 provide an unprecedented opportunity to study the two-body motion of a compact-object binary in the large velocity, highly nonlinear regime. We do not observe any deviations from general relativity, and place improved empirical bounds on several high-order post-Newtonian coefficients. From our observations we infer stellar-mass binary black hole merger rates lying in the range 9-240 Gpc-3 yr-1. These observations are beginning to inform astrophysical predictions of binary black hole formation rates, and indicate that future observing runs of the Advanced detector network will yield many more gravitational wave detections.

Black Hole Mergers in the Universe.

PubMed

Portegies Zwart SF; McMillan

2000-01-01

Mergers of black hole binaries are expected to release large amounts of energy in the form of gravitational radiation. However, binary evolution models predict merger rates that are too low to be of observational interest. In this Letter, we explore the possibility that black holes become members of close binaries via dynamical interactions with other stars in dense stellar systems. In star clusters, black holes become the most massive objects within a few tens of millions of years; dynamical relaxation then causes them to sink to the cluster core, where they form binaries. These black hole binaries become more tightly bound by superelastic encounters with other cluster members and are ultimately ejected from the cluster. The majority of escaping black hole binaries have orbital periods short enough and eccentricities high enough that the emission of gravitational radiation causes them to coalesce within a few billion years. We predict a black hole merger rate of about 1.6x10-7 yr-1 Mpc-3, implying gravity-wave detection rates substantially greater than the corresponding rates from neutron star mergers. For the first-generation Laser Interferometer Gravitational-Wave Observatory (LIGO-I), we expect about one detection during the first 2 years of operation. For its successor LIGO-II, the rate rises to roughly one detection per day. The uncertainties in these numbers are large. Event rates may drop by about an order of magnitude if the most massive clusters eject their black hole binaries early in their evolution.
Refining Binary Pulsar B1913+16's Gravitational Wave Test via a VLBI Parallax Measurement

NASA Astrophysics Data System (ADS)

Weisberg, Joel; Deller, Adam; Chatterjee, Shami; Nice, David

2018-01-01

The orbital decay of binary pulsar B1913+16 provided the first evidence of gravitational waves as predicted by General Relativity, and ruled out numerous previously viable alternative gravitational theories (e.g., Taylor & Weisberg, APJ, 253, 908, 1982). The gravitational wave emission and resulting orbital decay manifest themselves as an orbital period derivative. Subsequent observations (e.g., Weisberg and Huang 2016, APJ, 829, 55) have greatly refined the precision of the orbital period derivative measurement. The accuracy of the experiment is currently limited by our knowledge of the relative galactic accelerations of the binary and solar system barycenters, which make another contribution to the observed orbital period derivative. The magnitude of these accelerations depend on various galactic constants and on the pulsar distance.As our knowledge of the Galaxy and its motions has improved, the pulsar's distance has become the largest remaining source of uncertainty in the experiment.Therefore, we conducted a series of astrometric measurements of PSR B1913+16 with the Very Long Baseline Array. We report the pulsar parallax and distance derived from these measurements, and use them to correct our observed orbital period derivative for the above galactic acceleration term, thereby providing a more accurate test of gravitational radiation emission from the system.
GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral.

PubMed

Abbott, B P; Abbott, R; Abbott, T D; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V B; Affeldt, C; Afrough, M; Agarwal, B; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Aiello, L; Ain, A; Ajith, P; Allen, B; Allen, G; Allocca, A; Altin, P A; Amato, A; Ananyeva, A; Anderson, S B; Anderson, W G; Angelova, S V; Antier, S; Appert, S; Arai, K; Araya, M C; Areeda, J S; Arnaud, N; Arun, K G; Ascenzi, S; Ashton, G; Ast, M; Aston, S M; Astone, P; Atallah, D V; Aufmuth, P; Aulbert, C; AultONeal, K; Austin, C; Avila-Alvarez, A; Babak, S; Bacon, P; Bader, M K M; Bae, S; Bailes, M; Baker, P T; Baldaccini, F; Ballardin, G; Ballmer, S W; Banagiri, S; Barayoga, J C; Barclay, S E; Barish, B C; Barker, D; Barkett, K; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barta, D; Barthelmy, S D; Bartlett, J; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Bawaj, M; Bayley, J C; Bazzan, M; Bécsy, B; Beer, C; Bejger, M; Belahcene, I; Bell, A S; Berger, B K; Bergmann, G; Bernuzzi, S; Bero, J J; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Billman, C R; Birch, J; Birney, R; Birnholtz, O; Biscans, S; Biscoveanu, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blackman, J; Blair, C D; Blair, D G; Blair, R M; Bloemen, S; Bock, O; Bode, N; Boer, M; Bogaert, G; Bohe, A; Bondu, F; Bonilla, E; Bonnand, R; Boom, B A; Bork, R; Boschi, V; Bose, S; Bossie, K; Bouffanais, Y; Bozzi, A; Bradaschia, C; Brady, P R; Branchesi, M; Brau, J E; Briant, T; Brillet, A; Brinkmann, M; Brisson, V; Brockill, P; Broida, J E; Brooks, A F; Brown, D A; Brown, D D; Brunett, S; Buchanan, C C; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Byer, R L; Cabero, M; Cadonati, L; Cagnoli, G; Cahillane, C; Calderón Bustillo, J; Callister, T A; Calloni, E; Camp, J B; Canepa, M; Canizares, P; Cannon, K C; Cao, H; Cao, J; Capano, C D; Capocasa, E; Carbognani, F; Caride, S; Carney, M F; Carullo, G; Casanueva Diaz, J; 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2017-10-20

On August 17, 2017 at 12∶41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0×10^{4} years. We infer the component masses of the binary to be between 0.86 and 2.26 M_{⊙}, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60 M_{⊙}, with the total mass of the system 2.74_{-0.01}^{+0.04}M_{⊙}. The source was localized within a sky region of 28 deg^{2} (90% probability) and had a luminosity distance of 40_{-14}^{+8} Mpc, the closest and most precisely localized gravitational-wave signal yet. The association with the γ-ray burst GRB 170817A, detected by Fermi-GBM 1.7 s after the coalescence, corroborates the hypothesis of a neutron star merger and provides the first direct evidence of a link between these mergers and short γ-ray bursts. Subsequent identification of transient counterparts across the electromagnetic spectrum in the same location further supports the interpretation of this event as a neutron star merger. This unprecedented joint gravitational and electromagnetic observation provides insight into astrophysics, dense matter, gravitation, and cosmology.
Binary black holes' effects on electromagnetic fields.

PubMed

Palenzuela, Carlos; Anderson, Matthew; Lehner, Luis; Liebling, Steven L; Neilsen, David

2009-08-21

In addition to producing gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We here study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as a possible enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves.
Digging Deeper: Observing Primordial Gravitational Waves below the Binary-Black-Hole-Produced Stochastic Background.

PubMed

Regimbau, T; Evans, M; Christensen, N; Katsavounidis, E; Sathyaprakash, B; Vitale, S

2017-04-14

The merger rate of black hole binaries inferred from the detections in the first Advanced LIGO science run implies that a stochastic background produced by a cosmological population of mergers will likely mask the primordial gravitational wave background. Here we demonstrate that the next generation of ground-based detectors, such as the Einstein Telescope and Cosmic Explorer, will be able to observe binary black hole mergers throughout the Universe with sufficient efficiency that the confusion background can potentially be subtracted to observe the primordial background at the level of Ω_{GW}≃10^{-13} after 5 years of observation.
Supernova and Prompt Gravitational-wave Precursors to LIGO Gravitational-wave Sources and Short GRBs

NASA Astrophysics Data System (ADS)

Michaely, Erez; Perets, Hagai B.

2018-03-01

Binary black holes (BBHs) and binary neutron stars (BNSs) mergers have been recently detected through their gravitational-wave (GW) emission. A post-merger electromagnetic counterpart for the first BNS merger has been detected from seconds up to weeks after the merger. While such post-merger electromagnetic counterparts had been anticipated theoretically, far fewer electromagnetic precursors to GW sources have been proposed, and non have been observed. Here we show that a fraction of a few ×10‑3 (for a standard model) GW sources and short gamma-ray bursts (GRBs) observed by the Laser Interferometer Gravitational-wave Observatory (LIGO) could have been preceded by supernova (SN) explosions from years up to decades before the mergers. The GW sources are produced following the preceding binary evolution, the supernovae involved in the final formation of the GW source progenitors, and the natal kicks that likely accompany them. Together, these determine the orbits of surviving binaries, and hence the delay-time between the birth of the compact binary and its final merger through GW emission. We use data from binary evolution population-synthesis models to show that the delay-time distribution has a non-negligible tail of ultra-short delay-times between 1 and 100 years, thereby giving rise to potentially observable supernovae precursors to GW sources. Moreover, future LISA/DECIGO GW space-detectors will enable the detection of GW inspirals in the pre-merger stage weeks to decades before the final merger. These sources could therefore produce a unique type of promptly appearing LISA/DECIGO GW sources accompanied by coincident supernovae. The archival (and/or direct) detection of precursor (coincident) SNe with GW and/or short GRBs will provide unprecedented characterizations of the merging binaries, and their prior evolution through supernovae and natal kicks, otherwise inaccessible through other means.
Multivariate classification with random forests for gravitational wave searches of black hole binary coalescence

NASA Astrophysics Data System (ADS)

Baker, Paul T.; Caudill, Sarah; Hodge, Kari A.; Talukder, Dipongkar; Capano, Collin; Cornish, Neil J.

2015-03-01

Searches for gravitational waves produced by coalescing black hole binaries with total masses ≳25 M⊙ use matched filtering with templates of short duration. Non-Gaussian noise bursts in gravitational wave detector data can mimic short signals and limit the sensitivity of these searches. Previous searches have relied on empirically designed statistics incorporating signal-to-noise ratio and signal-based vetoes to separate gravitational wave candidates from noise candidates. We report on sensitivity improvements achieved using a multivariate candidate ranking statistic derived from a supervised machine learning algorithm. We apply the random forest of bagged decision trees technique to two separate searches in the high mass (≳25 M⊙ ) parameter space. For a search which is sensitive to gravitational waves from the inspiral, merger, and ringdown of binary black holes with total mass between 25 M⊙ and 100 M⊙ , we find sensitive volume improvements as high as 70±13%-109±11% when compared to the previously used ranking statistic. For a ringdown-only search which is sensitive to gravitational waves from the resultant perturbed intermediate mass black hole with mass roughly between 10 M⊙ and 600 M⊙ , we find sensitive volume improvements as high as 61±4%-241±12% when compared to the previously used ranking statistic. We also report how sensitivity improvements can differ depending on mass regime, mass ratio, and available data quality information. Finally, we describe the techniques used to tune and train the random forest classifier that can be generalized to its use in other searches for gravitational waves.
Is black-hole ringdown a memory of its progenitor?

PubMed

Kamaretsos, Ioannis; Hannam, Mark; Sathyaprakash, B S

2012-10-05

We perform an extensive numerical study of coalescing black-hole binaries to understand the gravitational-wave spectrum of quasinormal modes excited in the merged black hole. Remarkably, we find that the masses and spins of the progenitor are clearly encoded in the mode spectrum of the ringdown signal. Some of the mode amplitudes carry the signature of the binary's mass ratio, while others depend critically on the spins. Simulations of precessing binaries suggest that our results carry over to generic systems. Using Bayesian inference, we demonstrate that it is possible to accurately measure the mass ratio and a proper combination of spins even when the binary is itself invisible to a detector. Using a mapping of the binary masses and spins to the final black-hole spin allows us to further extract the spin components of the progenitor. Our results could have tremendous implications for gravitational astronomy by facilitating novel tests of general relativity using merging black holes.
TIME DELAY AND ACCRETION DISK SIZE MEASUREMENTS IN THE LENSED QUASAR SBS 0909+532 FROM MULTIWAVELENGTH MICROLENSING ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hainline, Laura J.; Morgan, Christopher W.; MacLeod, Chelsea L.

2013-09-01

We present three complete seasons and two half-seasons of Sloan Digital Sky Survey (SDSS) r-band photometry of the gravitationally lensed quasar SBS 0909+532 from the U.S. Naval Observatory, as well as two seasons each of SDSS g-band and r-band monitoring from the Liverpool Robotic Telescope. Using Monte Carlo simulations to simultaneously measure the system's time delay and model the r-band microlensing variability, we confirm and significantly refine the precision of the system's time delay to {Delta}t{sub AB} = 50{sub -4}{sup +2} days, where the stated uncertainties represent the bounds of the formal 1{sigma} confidence interval. There may be a conflictmore » between the time delay measurement and a lens consisting of a single galaxy. While models based on the Hubble Space Telescope astrometry and a relatively compact stellar distribution can reproduce the observed delay, the models have somewhat less dark matter than we would typically expect. We also carry out a joint analysis of the microlensing variability in the r and g bands to constrain the size of the quasar's continuum source at these wavelengths, obtaining log {l_brace}(r{sub s,r}/cm)[cos i/0.5]{sup 1/2}{r_brace} = 15.3 {+-} 0.3 and log {l_brace}(r{sub s,g}/cm)[cos i/0.5]{sup 1/2}{r_brace} = 14.8 {+-} 0.9, respectively. Our current results do not formally constrain the temperature profile of the accretion disk but are consistent with the expectations of standard thin disk theory.« less
A Likely Detection of a Two-planet System in a Low-magnification Microlensing Event

NASA Astrophysics Data System (ADS)

Suzuki, D.; Bennett, D. P.; Udalski, A.; Bond, I. A.; Sumi, T.; Han, C.; Kim, Ho-il.; Abe, F.; Asakura, Y.; Barry, R. K.; Bhattacharya, A.; Donachie, M.; Freeman, M.; Fukui, A.; Hirao, Y.; Itow, Y.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Onishi, K.; Oyokawa, H.; Ranc, C.; Rattenbury, N. J.; Saito, To.; Sharan, A.; Sullivan, D. J.; Tristram, P. J.; Yonehara, A.; MOA Collaboration; Poleski, R.; Mróz, P.; Skowron, J.; Szymański, M. K.; Soszyński, I.; Kozłowski, S.; Pietrukowicz, P.; Wyrzykowski, Ł.; Ulaczyk, K.; OGLE Collaboration

2018-06-01

We report on the analysis of a microlensing event, OGLE-2014-BLG-1722, that showed two distinct short-term anomalies. The best-fit model to the observed light curves shows that the two anomalies are explained with two planetary mass ratio companions to the primary lens. Although a binary-source model is also able to explain the second anomaly, it is marginally ruled out by 3.1σ. The two-planet model indicates that the first anomaly was caused by planet “b” with a mass ratio of q=({4.5}-0.6+0.7)× {10}-4 and projected separation in units of the Einstein radius, s = 0.753 ± 0.004. The second anomaly reveals planet “c” with a mass ratio of {q}2=({7.0}-1.7+2.3)× {10}-4 with Δχ 2 ∼ 170 compared to the single-planet model. Its separation has two degenerated solutions: the separation of planet c is s 2 = 0.84 ± 0.03 and 1.37 ± 0.04 for the close and wide models, respectively. Unfortunately, this event does not show clear finite-source and microlensing parallax effects; thus, we estimated the physical parameters of the lens system from Bayesian analysis. This gives the masses of planets b and c as {m}{{b}}={56}-33+51 and {m}{{c}}={85}-51+86 {M}\\oplus , respectively, and they orbit a late-type star with a mass of {M}host} ={0.40}-0.24+0.36 {M}ȯ located at {D}{{L}}={6.4}-1.8+1.3 {kpc} from us. The projected distances between the host and planets are {r}\\perp ,{{b}}=1.5+/- 0.6 {au} for planet b and {r}\\perp ,{{c}}={1.7}-0.6+0.7 {au} and {r}\\perp ,{{c}}={2.7}-1.0+1.1 {au} for the close and wide models of planet c. If the two-planet model is true, then this is the third multiple-planet system detected using the microlensing method and the first multiple-planet system detected in low-magnification events, which are dominant in the microlensing survey data. The occurrence rate of multiple cold gas giant systems is estimated using the two such detections and a simple extrapolation of the survey sensitivity of the 6 yr MOA microlensing survey combined with the 4 yr μFUN detection efficiency. It is estimated that 6% ± 2% of stars host two cold giant planets.
Testing the Binary Black Hole Nature of a Compact Binary Coalescence

NASA Astrophysics Data System (ADS)

Krishnendu, N. V.; Arun, K. G.; Mishra, Chandra Kant

2017-09-01

We propose a novel method to test the binary black hole nature of compact binaries detectable by gravitational wave (GW) interferometers and, hence, constrain the parameter space of other exotic compact objects. The spirit of the test lies in the "no-hair" conjecture for black holes where all properties of a Kerr black hole are characterized by its mass and spin. The method relies on observationally measuring the quadrupole moments of the compact binary constituents induced due to their spins. If the compact object is a Kerr black hole (BH), its quadrupole moment is expressible solely in terms of its mass and spin. Otherwise, the quadrupole moment can depend on additional parameters (such as the equation of state of the object). The higher order spin effects in phase and amplitude of a gravitational waveform, which explicitly contains the spin-induced quadrupole moments of compact objects, hence, uniquely encode the nature of the compact binary. Thus, we argue that an independent measurement of the spin-induced quadrupole moment of the compact binaries from GW observations can provide a unique way to distinguish binary BH systems from binaries consisting of exotic compact objects.
Testing the Binary Black Hole Nature of a Compact Binary Coalescence.

PubMed

Krishnendu, N V; Arun, K G; Mishra, Chandra Kant

2017-09-01

We propose a novel method to test the binary black hole nature of compact binaries detectable by gravitational wave (GW) interferometers and, hence, constrain the parameter space of other exotic compact objects. The spirit of the test lies in the "no-hair" conjecture for black holes where all properties of a Kerr black hole are characterized by its mass and spin. The method relies on observationally measuring the quadrupole moments of the compact binary constituents induced due to their spins. If the compact object is a Kerr black hole (BH), its quadrupole moment is expressible solely in terms of its mass and spin. Otherwise, the quadrupole moment can depend on additional parameters (such as the equation of state of the object). The higher order spin effects in phase and amplitude of a gravitational waveform, which explicitly contains the spin-induced quadrupole moments of compact objects, hence, uniquely encode the nature of the compact binary. Thus, we argue that an independent measurement of the spin-induced quadrupole moment of the compact binaries from GW observations can provide a unique way to distinguish binary BH systems from binaries consisting of exotic compact objects.
The first gravitational-wave burst GW150914, as predicted by the scenario machine

NASA Astrophysics Data System (ADS)

Lipunov, V. M.; Kornilov, V.; Gorbovskoy, E.; Tiurina, N.; Balanutsa, P.; Kuznetsov, A.

2017-02-01

The Advanced LIGO observatory recently reported (Abbott et al., 2016a) the first direct detection of gravitational waves predicted by Einstein (1916). The detection of this event was predicted in 1997 on the basis of the Scenario Machine population synthesis calculations (Lipunov et al., 1997b) Now we discuss the parameters of binary black holes and event rates predicted by different scenarios of binary evolution. We give a simple explanation of the big difference between detected black hole masses and the mean black hole masses observed in of X-ray Nova systems. The proximity of the masses of the components of GW150914 is in good agreement with the observed initial mass ratio distribution in massive binary systems, as is used in Scenario Machine calculations for massive binaries.
Probing the Milky Way electron density using multi-messenger astronomy

NASA Astrophysics Data System (ADS)

Breivik, Katelyn; Larson, Shane

2015-04-01

Multi-messenger observations of ultra-compact binaries in both gravitational waves and electromagnetic radiation supply highly complementary information, providing new ways of characterizing the internal dynamics of these systems, as well as new probes of the galaxy itself. Electron density models, used in pulsar distance measurements via the electron dispersion measure, are currently not well constrained. Simultaneous radio and gravitational wave observations of pulsars in binaries provide a method of measuring the average electron density along the line of sight to the pulsar, thus giving a new method for constraining current electron density models. We present this method and assess its viability with simulations of the compact binary component of the Milky Way using the public domain binary evolution code, BSE. This work is supported by NASA Award NNX13AM10G.
Parameter estimation method that directly compares gravitational wave observations to numerical relativity

NASA Astrophysics Data System (ADS)

Lange, J.; O'Shaughnessy, R.; Boyle, M.; Calderón Bustillo, J.; Campanelli, M.; Chu, T.; Clark, J. A.; Demos, N.; Fong, H.; Healy, J.; Hemberger, D. A.; Hinder, I.; Jani, K.; Khamesra, B.; Kidder, L. E.; Kumar, P.; Laguna, P.; Lousto, C. O.; Lovelace, G.; Ossokine, S.; Pfeiffer, H.; Scheel, M. A.; Shoemaker, D. M.; Szilagyi, B.; Teukolsky, S.; Zlochower, Y.

2017-11-01

We present and assess a Bayesian method to interpret gravitational wave signals from binary black holes. Our method directly compares gravitational wave data to numerical relativity (NR) simulations. In this study, we present a detailed investigation of the systematic and statistical parameter estimation errors of this method. This procedure bypasses approximations used in semianalytical models for compact binary coalescence. In this work, we use the full posterior parameter distribution for only generic nonprecessing binaries, drawing inferences away from the set of NR simulations used, via interpolation of a single scalar quantity (the marginalized log likelihood, ln L ) evaluated by comparing data to nonprecessing binary black hole simulations. We also compare the data to generic simulations, and discuss the effectiveness of this procedure for generic sources. We specifically assess the impact of higher order modes, repeating our interpretation with both l ≤2 as well as l ≤3 harmonic modes. Using the l ≤3 higher modes, we gain more information from the signal and can better constrain the parameters of the gravitational wave signal. We assess and quantify several sources of systematic error that our procedure could introduce, including simulation resolution and duration; most are negligible. We show through examples that our method can recover the parameters for equal mass, zero spin, GW150914-like, and unequal mass, precessing spin sources. Our study of this new parameter estimation method demonstrates that we can quantify and understand the systematic and statistical error. This method allows us to use higher order modes from numerical relativity simulations to better constrain the black hole binary parameters.
Hidden-sector Spectroscopy with Gravitational Waves from Binary Neutron Stars

NASA Astrophysics Data System (ADS)

Croon, Djuna; Nelson, Ann E.; Sun, Chen; Walker, Devin G. E.; Xianyu, Zhong-Zhi

2018-05-01

We show that neutron star (NS) binaries can be ideal laboratories to probe hidden sectors with a long-range force. In particular, it is possible for gravitational wave (GW) detectors such as LIGO and Virgo to resolve the correction of waveforms from ultralight dark gauge bosons coupled to NSs. We observe that the interaction of the hidden sector affects both the GW frequency and amplitude in a way that cannot be fitted by pure gravity.
Searching for the full symphony of black hole binary mergers

NASA Astrophysics Data System (ADS)

Harry, Ian; Bustillo, Juan Calderón; Nitz, Alex

2018-01-01

Current searches for the gravitational-wave signature of compact binary mergers rely on matched-filtering data from interferometric observatories with sets of modeled gravitational waveforms. These searches currently use model waveforms that do not include the higher-order mode content of the gravitational-wave signal. Higher-order modes are important for many compact binary mergers and their omission reduces the sensitivity to such sources. In this work we explore the sensitivity loss incurred from omitting higher-order modes. We present a new method for searching for compact binary mergers using waveforms that include higher-order mode effects, and evaluate the sensitivity increase that using our new method would allow. We find that, when evaluating sensitivity at a constant rate-of-false alarm, and when including the fact that signal-consistency tests can reject some signals that include higher-order mode content, we observe a sensitivity increase of up to a factor of 2 in volume for high mass ratio, high total-mass systems. For systems with equal mass, or with total mass ˜50 M⊙, we see more modest sensitivity increases, <10 %, which indicates that the existing search is already performing well. Our new search method is also directly applicable in searches for generic compact binaries.
Detecting Lorentz Violations with Gravitational Waves From Black Hole Binaries

NASA Astrophysics Data System (ADS)

Sotiriou, Thomas P.

2018-01-01

Gravitational wave observations have been used to test Lorentz symmetry by looking for dispersive effects that are caused by higher order corrections to the dispersion relation. In this Letter I argue on general grounds that, when such corrections are present, there will also be a scalar excitation. Hence, a smoking-gun observation of Lorentz symmetry breaking would be the direct detection of scalar waves that travel at a speed other than the speed of the standard gravitational wave polarizations or the speed of light. Interestingly, in known Lorentz-breaking gravity theories the difference between the speeds of scalar and tensor waves is virtually unconstrained, whereas the difference between the latter and the speed of light is already severely constrained by the coincident detection of gravitational waves and gamma rays from a binary neutron star merger.

An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi -GBM Detection of GRB 170817A

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldstein, A.; Roberts, O. J.; Connaughton, V.

On 2017 August 17 at 12:41:06 UTC the Fermi Gamma-ray Burst Monitor (GBM) detected and triggered on the short gamma-ray burst (GRB) 170817A. Approximately 1.7 s prior to this GRB, the Laser Interferometer Gravitational-wave Observatory triggered on a binary compact merger candidate associated with the GRB. This is the first unambiguous coincident observation of gravitational waves and electromagnetic radiation from a single astrophysical source and marks the start of gravitational-wave multi-messenger astronomy. We report the GBM observations and analysis of this ordinary short GRB, which extraordinarily confirms that at least some short GRBs are produced by binary compact mergers.
Constraining Modified Theories of Gravity with Gravitational-Wave Stochastic Backgrounds

NASA Astrophysics Data System (ADS)

Maselli, Andrea; Marassi, Stefania; Ferrari, Valeria; Kokkotas, Kostas; Schneider, Raffaella

2016-08-01

The direct discovery of gravitational waves has finally opened a new observational window on our Universe, suggesting that the population of coalescing binary black holes is larger than previously expected. These sources produce an unresolved background of gravitational waves, potentially observable by ground-based interferometers. In this Letter we investigate how modified theories of gravity, modeled using the parametrized post-Einsteinian formalism, affect the expected signal, and analyze the detectability of the resulting stochastic background by current and future ground-based interferometers. We find the constraints that Advanced LIGO would be able to set on modified theories, showing that they may significantly improve the current bounds obtained from astrophysical observations of binary pulsars.
An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A

NASA Astrophysics Data System (ADS)

Goldstein, A.; Veres, P.; Burns, E.; Briggs, M. S.; Hamburg, R.; Kocevski, D.; Wilson-Hodge, C. A.; Preece, R. D.; Poolakkil, S.; Roberts, O. J.; Hui, C. M.; Connaughton, V.; Racusin, J.; von Kienlin, A.; Dal Canton, T.; Christensen, N.; Littenberg, T.; Siellez, K.; Blackburn, L.; Broida, J.; Bissaldi, E.; Cleveland, W. H.; Gibby, M. H.; Giles, M. M.; Kippen, R. M.; McBreen, S.; McEnery, J.; Meegan, C. A.; Paciesas, W. S.; Stanbro, M.

2017-10-01

On 2017 August 17 at 12:41:06 UTC the Fermi Gamma-ray Burst Monitor (GBM) detected and triggered on the short gamma-ray burst (GRB) 170817A. Approximately 1.7 s prior to this GRB, the Laser Interferometer Gravitational-wave Observatory triggered on a binary compact merger candidate associated with the GRB. This is the first unambiguous coincident observation of gravitational waves and electromagnetic radiation from a single astrophysical source and marks the start of gravitational-wave multi-messenger astronomy. We report the GBM observations and analysis of this ordinary short GRB, which extraordinarily confirms that at least some short GRBs are produced by binary compact mergers.
Cosmological perturbation effects on gravitational-wave luminosity distance estimates

NASA Astrophysics Data System (ADS)

Bertacca, Daniele; Raccanelli, Alvise; Bartolo, Nicola; Matarrese, Sabino

2018-06-01

Waveforms of gravitational waves provide information about a variety of parameters for the binary system merging. However, standard calculations have been performed assuming a FLRW universe with no perturbations. In reality this assumption should be dropped: we show that the inclusion of cosmological perturbations translates into corrections to the estimate of astrophysical parameters derived for the merging binary systems. We compute corrections to the estimate of the luminosity distance due to velocity, volume, lensing and gravitational potential effects. Our results show that the amplitude of the corrections will be negligible for current instruments, mildly important for experiments like the planned DECIGO, and very important for future ones such as the Big Bang Observer.
Characterizing Lenses and Lensed Stars of High-magnification Single-lens Gravitational Microlensing Events with Lenses Passing over Source Stars

NASA Astrophysics Data System (ADS)

Choi, J.-Y.; Shin, I.-G.; Park, S.-Y.; Han, C.; Gould, A.; Sumi, T.; Udalski, A.; Beaulieu, J.-P.; Street, R.; Dominik, M.; Allen, W.; Almeida, L. A.; Bos, M.; Christie, G. W.; Depoy, D. L.; Dong, S.; Drummond, J.; Gal-Yam, A.; Gaudi, B. S.; Henderson, C. B.; Hung, L.-W.; Jablonski, F.; Janczak, J.; Lee, C.-U.; Mallia, F.; Maury, A.; McCormick, J.; McGregor, D.; Monard, L. A. G.; Moorhouse, D.; Muñoz, J. A.; Natusch, T.; Nelson, C.; Park, B.-G.; Pogge, R. W.; "TG" Tan, T.-G.; Thornley, G.; Yee, J. C.; μFUN Collaboration; Abe, F.; Barnard, E.; Baudry, J.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Freeman, M.; Fukui, A.; Furusawa, K.; Hayashi, F.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Kobara, S.; Korpela, A.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Nagaya, M.; Nishimoto, K.; Ohnishi, K.; Okumura, T.; Omori, K.; Perrott, Y. C.; Rattenbury, N.; Saito, To.; Skuljan, L.; Sullivan, D. J.; Suzuki, D.; Suzuki, K.; Sweatman, W. L.; Takino, S.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Poleski, R.; Ulaczyk, K.; Wyrzykowski, Ł.; Kozłowski, S.; Pietrukowicz, P.; OGLE Collaboration; Albrow, M. D.; Bachelet, E.; Batista, V.; Bennett, C. S.; Bowens-Rubin, R.; Brillant, S.; Cassan, A.; Cole, A.; Corrales, E.; Coutures, Ch.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Fouqué, P.; Greenhill, J.; Kane, S. R.; Menzies, J.; Sahu, K. C.; Wambsganss, J.; Williams, A.; Zub, M.; PLANET Collaboration; Allan, A.; Bramich, D. M.; Browne, P.; Clay, N.; Fraser, S.; Horne, K.; Kains, N.; Mottram, C.; Snodgrass, C.; Steele, I.; Tsapras, Y.; RoboNet Collaboration; Alsubai, K. A.; Bozza, V.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Finet, F.; Gerner, T.; Glitrup, M.; Grundahl, F.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hundertmark, M.; Jørgensen, U. G.; Kerins, E.; Liebig, C.; Maier, G.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Proft, S.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Schäfer, S.; Schönebeck, F.; Skottfelt, J.; Surdej, J.; Southworth, J.; Zimmer, F.; MiNDSTEp Consortium

2012-05-01

We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of θE ~ 0.08 mas combined with the short timescale of t E ~ 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of ~0.84 M ⊙ is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio.
Planetary mass function and planetary systems

NASA Astrophysics Data System (ADS)

Dominik, M.

2011-02-01

With planets orbiting stars, a planetary mass function should not be seen as a low-mass extension of the stellar mass function, but a proper formalism needs to take care of the fact that the statistical properties of planet populations are linked to the properties of their respective host stars. This can be accounted for by describing planet populations by means of a differential planetary mass-radius-orbit function, which together with the fraction of stars with given properties that are orbited by planets and the stellar mass function allows the derivation of all statistics for any considered sample. These fundamental functions provide a framework for comparing statistics that result from different observing techniques and campaigns which all have their very specific selection procedures and detection efficiencies. Moreover, recent results both from gravitational microlensing campaigns and radial-velocity surveys of stars indicate that planets tend to cluster in systems rather than being the lonely child of their respective parent star. While planetary multiplicity in an observed system becomes obvious with the detection of several planets, its quantitative assessment however comes with the challenge to exclude the presence of further planets. Current exoplanet samples begin to give us first hints at the population statistics, whereas pictures of planet parameter space in its full complexity call for samples that are 2-4 orders of magnitude larger. In order to derive meaningful statistics, however, planet detection campaigns need to be designed in such a way that well-defined fully deterministic target selection, monitoring and detection criteria are applied. The probabilistic nature of gravitational microlensing makes this technique an illustrative example of all the encountered challenges and uncertainties.
Gravitational lensing in modified Newtonian dynamics

NASA Astrophysics Data System (ADS)

Mortlock, Daniel J.; Turner, Edwin L.

2001-10-01

Modified Newtonian dynamics (MOND) is an alternative theory of gravity that aims to explain large-scale dynamics without recourse to any form of dark matter. However, the theory is incomplete, lacking a relativistic counterpart, and so makes no definite predictions about gravitational lensing. The most obvious form that MONDian lensing might take is that photons experience twice the deflection of massive particles moving at the speed of light, as in general relativity (GR). In such a theory there is no general thin-lens approximation (although one can be made for spherically symmetric deflectors), but the three-dimensional acceleration of photons is in the same direction as the relativistic acceleration would be. In regimes where the deflector can reasonably be approximated as a single point-mass (specifically low-optical depth microlensing and weak galaxy-galaxy lensing), this naive formulation is consistent with observations. Forthcoming galaxy-galaxy lensing data and the possibility of cosmological microlensing have the potential to distinguish unambiguously between GR and MOND. Some tests can also be performed with extended deflectors, for example by using surface brightness measurements of lens galaxies to model quasar lenses, although the breakdown of the thin-lens approximation allows an extra degree of freedom. None the less, it seems unlikely that simple ellipsoidal galaxies can satisfy both constraints. Furthermore, the low-density universe implied by MOND must be completely dominated by the cosmological constant (to fit microwave background observations), and such models are at odds with the low frequency of quasar lenses. These conflicts might be resolved by a fully consistent relativistic extension to MOND; the alternative is that MOND is not an accurate description of the Universe.
Simulating Gravitational Wave Emission from Massive Black Hole Binaries

NASA Technical Reports Server (NTRS)

Centrella, Joan

2008-01-01

The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. In the past few years, this situation has changed dramatically, with a series of amazing breakthroughs. This talk will focus on the recent advances that are revealing these waveforms. highlighting their astrophysical consequences and the dramatic new potential for discovery that arises when merging black holes will be observed using gravitational waves.
Gravitational waves from neutron stars and asteroseismology.

PubMed

Ho, Wynn C G

2018-05-28

Neutron stars are born in the supernova explosion of massive stars. Neutron stars rotate as stably as atomic clocks and possess densities exceeding that of atomic nuclei and magnetic fields millions to billions of times stronger than those created in laboratories on the Earth. The physical properties of neutron stars are determined by many areas of fundamental physics, and detection of gravitational waves can provide invaluable insights into our understanding of these areas. Here, we describe some of the physics and astrophysics of neutron stars and how traditional electromagnetic wave observations provide clues to the sorts of gravitational waves we expect from these stars. We pay particular attention to neutron star fluid oscillations, examining their impact on electromagnetic and gravitational wave observations when these stars are in a wide binary or isolated system, then during binary inspiral right before merger, and finally at times soon after merger.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).
Gravitational waves from neutron stars and asteroseismology

NASA Astrophysics Data System (ADS)

Ho, Wynn C. G.

2018-05-01

Neutron stars are born in the supernova explosion of massive stars. Neutron stars rotate as stably as atomic clocks and possess densities exceeding that of atomic nuclei and magnetic fields millions to billions of times stronger than those created in laboratories on the Earth. The physical properties of neutron stars are determined by many areas of fundamental physics, and detection of gravitational waves can provide invaluable insights into our understanding of these areas. Here, we describe some of the physics and astrophysics of neutron stars and how traditional electromagnetic wave observations provide clues to the sorts of gravitational waves we expect from these stars. We pay particular attention to neutron star fluid oscillations, examining their impact on electromagnetic and gravitational wave observations when these stars are in a wide binary or isolated system, then during binary inspiral right before merger, and finally at times soon after merger. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.
Using LISA to Learn How Pairs of Black Holes Formed

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-11-01

Artists impression of the European Space Agencys Laser Interferometer Space Antenna, currently planned for a 2034 launch. [NASA]How are black-hole binaries built? Observations of gravitational waves from these systems made using the European Space Agencys upcoming mission, the Laser Interferometer Space Antenna (LISA) may be able to reveal their origins.Formation ChannelsThere are two primary placeswhere stellar-mass black-hole binaries are thought to form:In isolation in the galactic field, as the components of a stellar binary independently evolve into black holes but remain bound to each other.In dense stellar environments like globular clusters, where the high density of already-formed black holes can cause a pair to dynamically interact and form a binary before being ejected from the cluster.Can we differentiate between these origins based on future detections of gravitational waves from black-hole binaries? A team of scientists led by Katelyn Breivik (CIERA, Northwestern University) thinks that we can!The gravitational-wave spectrum and how we detect it (click for a closer look!). While ground-based interferometers like LIGO detect black-hole binaries in the final moments before merger, LISAs lower frequency band will allow it to detect binaries earlier in their inspiral. [NASA Goddard SFC]Differentiation by EccentricityBreivik and collaborators believe that the key clue is the binarys eccentricity. Gravitational-wave emission will eventually circularize all black-hole binaries during their inspiral. But in the first formation scenario, binary evolution processes like tidal circularization and mass transfer will reduce the binarys eccentricity early on whereas in the second scenario, the binaries that form in globular clusters may retain eccentricity in their orbits long enough that we can detect it.Ground-based interferometers wont be up to this task; by the time the binary orbits shrink enough to evolve into the LIGO frequency band, the orbits wont have measurable eccentricity anymore. But the upcoming space-based LISA mission, which will operate in a lower frequency band, might be able to pick up this signature.To determine if LISA can pull it off, Breivik and collaborators simulate two populations of binary black holes: one evolved in isolation in galactic fields, and the other formed dynamically in globular clusters and then ejected. The authors then explore the evolution of these populations masses and eccentricities as their orbits narrow into the LISA-detectable frequency band.Eccentricity evolution tracks as a function of gravitational-wave frequency for black-hole binaries formed in dynamical scenarios (black) and in isolation (blue for those with a common-envelope episode, green for those without). Eccentricities above 10-2 are measurable for all binaries; those above 10-3 are measurable for 90%. LISAs frequency band is shown in grey. [Breivik et al. 2016]Separating PopulationsBreivik and collaborators find that LISA will be able to make several important distinctions. First, if LISA detects binary black holes with eccentricities of e 0.01 at frequencies above 10-2 Hz, we can be fairly certainthat these originated from dynamical processes in dense stellar environments.For binary black holes detected with eccentricities of e 0.01 at lower frequencies, they could either have formed in dense stellar environments or they could have formed in isolation. Based on this studys results, however, those with measurable eccentricities that formed in isolation mostlikely originated from a common-envelope formation. Measuring eccentricities of such systems in the future could provide constraints on the physics of how this formation mechanism works.Though the field of gravitational-wave astronomy is only just beginning, its future is promising! Theoretical studies like this one will help us to extracta greater understanding from the observations we can expect down the road.BonusCheck out this beautiful simulationfrom Northwestern Visualization and Carl Rodriguez (a co-author on the above study) that shows what the formation of a binary black hole in a globular cluster might look like!http://aasnova.org/wp-content/uploads/2016/11/accelerated_nbody_hd.mp4CitationKatelyn Breivik et al 2016 ApJL 830 L18. doi:10.3847/2041-8205/830/1/L18
Radio crickets: chirping jets from black hole binaries entering their gravitational wave inspiral

NASA Astrophysics Data System (ADS)

Kulkarni, Girish; Loeb, Abraham

2016-03-01

We study a novel electromagnetic signature of supermassive black hole (BH) binaries whose inspiral starts being dominated by gravitational wave (GW) emission. Recent simulations suggest that the binary's member BHs can continue to accrete gas from the circumbinary accretion disc in this phase of the binary's evolution, all the way until coalescence. If one of the binary members produces a radio jet as a result of accretion, the jet precesses along a biconical surface due to the binary's orbital motion. When the binary enters the GW phase of its evolution, the opening angle widens, the jet exhibits milliarcsecond-scale wiggles, and the conical surface of jet precession is twisted due to apparent superluminal motion. The rapidly increasing orbital velocity of the binary gives the jet an appearance of a `chirp'. This helical chirping morphology of the jet can be used to infer the binary parameters. For binaries with mass 107-1010 M⊙ at redshifts z < 0.5, monitoring these features in current and archival data will place a lower limit on sources that could be detected by Evolved Laser Interferometer Space Antenna and Pulsar Timing Arrays. In the future, microarcsecond interferometry with the Square Kilometre Array will increase the potential usefulness of this technique.
PROSPECTS FOR CHARACTERIZING HOST STARS OF THE PLANETARY SYSTEM DETECTIONS PREDICTED FOR THE KOREAN MICROLENSING TELESCOPE NETWORK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henderson, Calen B., E-mail: henderson@astronomy.ohio-state.edu

2015-02-10

I investigate the possibility of constraining the flux of the lens (i.e., host star) for the types of planetary systems the Korean Microlensing Telescope Network is predicted to find. I examine the potential to obtain lens flux measurements by (1) imaging the lens once it is spatially resolved from the source, (2) measuring the elongation of the point-spread function of the microlensing target (lens+source) when the lens and source are still unresolved, and (3) taking prompt follow-up photometry. In each case I simulate the observing programs for a representative example of current ground-based adaptive optics (AO) facilities (specifically NACO onmore » the Very Large Telescope), future ground-based AO facilities (GMTIFS on the Giant Magellan Telescope, GMT), and future space telescopes (NIRCAM on the James Webb Space Telescope, JWST). Given the predicted distribution of relative lens-source proper motions, I find that the lens flux could be measured to a precision of σ{sub H{sub ℓ}}≤0.1 for ≳60% of planet detections ≥5 yr after each microlensing event for a simulated observing program using GMT, which images resolved lenses. NIRCAM on JWST would be able to carry out equivalently high-precision measurements for ∼28% of events Δt = 10 yr after each event by imaging resolved lenses. I also explore the effects various blend components would have on the mass derived from prompt follow-up photometry, including companions to the lens, companions to the source, and unassociated interloping stars. I find that undetected blend stars would cause catastrophic failures (i.e., >50% fractional uncertainty in the inferred lens mass) for ≲ (16 · f {sub bin})% of planet detections, where f {sub bin} is the binary fraction, with the majority of these failures occurring for host stars with mass ≲0.3 M {sub ☉}.« less
Exploring Sources of Gravitational Waves From Star Cluster Dynamics

NASA Astrophysics Data System (ADS)

Fuhrman, Joshua; Geller, Aaron M.; Rodriguez, Carl L.; Rasio, Frederic A.

2017-01-01

The recent detection of ripples in space-time by the Laser Interferometer Gravitational-wave Observatory (LIGO) has ushered in the age of gravitational wave astronomy. Binary black hole systems formed in the center of modest star clusters offer a possible gravitational wave source detectable by the LIGO or Laser Interferometer Space Antennae (LISA) collaborations. We simulate clusters containing 1-40K objects using direct integration from a customized version of NBODY6++GPU. We identify Binary Black Hole (BBH) objects of interest by an inspiral time sufficiently less than the age of the universe such that their coalescence might be detectable. Such objects are tracked through time within our N-body simulations to characterize the role of dynamics in the evolution of the BBH system using member exchanges and large orbital eccentricity changes as indicators of dynamic’s influence. We produce 41 BBH system candidates for detection by LIGO, all of which are dynamically formed. We observe several trends in the production of these potential BBH LIGO sources: a low-N cutoff in initial cluster size between 1-5K objects, high eccentricity oscillations, and the frequent formation of stable triple systems with the BBH as the inner binary.
Binary Black Holes, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Centrella, Joan

2008-01-01

The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields. We need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Binary Black Holes, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Centrella, Joan

2008-01-01

The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities. causing them to crash well before the black hole:, in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Binary Black Holes, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Centrella, Joan

2008-01-01

The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Binary Black Holes, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Centrella, Joan

2009-01-01

The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Binary Black Holes, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Centrella, Joan

2007-01-01

The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA
Binary Black Holes, Gravitational Waves, and Numerical Relativity

NASA Technical Reports Server (NTRS)

Centrella, Joan

2007-01-01

The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simutation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.

Extreme gravity tests with gravitational waves from compact binary coalescences: (I) inspiral-merger

NASA Astrophysics Data System (ADS)

Berti, Emanuele; Yagi, Kent; Yunes, Nicolás

2018-04-01

The observation of the inspiral and merger of compact binaries by the LIGO/Virgo collaboration ushered in a new era in the study of strong-field gravity. We review current and future tests of strong gravity and of the Kerr paradigm with gravitational-wave interferometers, both within a theory-agnostic framework (the parametrized post-Einsteinian formalism) and in the context of specific modified theories of gravity (scalar-tensor, Einstein-dilaton-Gauss-Bonnet, dynamical Chern-Simons, Lorentz-violating, and extra dimensional theories). In this contribution we focus on (i) the information carried by the inspiral radiation, and (ii) recent progress in numerical simulations of compact binary mergers in modified gravity.
OGLE-2013-BLG-0132Lb and OGLE-2013-BLG-1721Lb: Two Saturn-mass Planets Discovered around M-dwarfs

NASA Astrophysics Data System (ADS)

Mróz, Przemek; Udalski, A.; Bond, I. A.; Skowron, J.; Sumi, T.; Han, C.; Szymański, M. K.; Soszyński, I.; Poleski, R.; Pietrukowicz, P.; Kozłowski, S.; Wyrzykowski, Ł.; Ulaczyk, K.; OGLE Collaboration; Abe, F.; Asakura, Y.; Barry, R. K.; Bennett, D. P.; Bhattacharya, A.; Donachie, M.; Evans, P.; Fukui, A.; Hirao, Y.; Itow, Y.; Koshimoto, N.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Ranc, C.; Rattenbury, N. J.; Saito, To.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yamada, T.; Yamada, T.; Yonehara, A.; The MOA Collaboration

2017-11-01

We present the discovery of two planetary systems consisting of a Saturn-mass planet orbiting an M-dwarf, which were detected in faint microlensing events OGLE-2013-BLG-0132 and OGLE-2013-BLG-1721. The planetary anomalies were covered with high cadence by Optical Gravitational Lensing Experiment (OGLE) and Microlensing Observations in Astrophysics (MOA) photometric surveys. The light curve modeling indicates that the planet-to-host mass ratios are (5.15+/- 0.28)× {10}-4 and (13.18+/- 0.72)× {10}-4, respectively. Both events were too short and too faint to measure a reliable parallax signal and hence the lens mass. We therefore used a Bayesian analysis to estimate the masses of both planets: {0.29}-0.13+0.16 {M}{Jup} (OGLE-2013-BLG-0132Lb) and {0.64}-0.31+0.35 {M}{Jup} (OGLE-2013-BLG-1721Lb). Thanks to a high relative proper motion, OGLE-2013-BLG-0132 is a promising candidate for the high-resolution imaging follow-up. Both planets belong to an increasing sample of sub-Jupiter-mass planets orbiting M-dwarfs beyond the snow line.
REVIEWS OF TOPICAL PROBLEMS: Gravitational wave astronomy: in anticipation of first sources to be detected

NASA Astrophysics Data System (ADS)

Grishchuk, Leonid P.; Lipunov, V. M.; Postnov, Konstantin A.; Prokhorov, Mikhail E.; Sathyaprakash, B. S.

2001-01-01

The first generation of long-baseline laser interferometric detectors of gravitational waves will start collecting data in 2001 - 2003. We carefully analyse their planned performance and compare it with the expected strengths of astrophysical sources. The scientific importance of the anticipated discovery of various gravitational wave signals and the reliability of theoretical predictions are taken into account in our analysis. We try to be conservative in evaluating both the theoretical uncertainties in the parameters of the source and the prospects of its detection. Upon considering many possible sources, we place our emphasis on (i) inspiraling binaries consisting of stellar mass black holes and (ii) relic gravitational waves. We conclude that inspiraling binary black holes are likely to be detected by the early ground-based interferometers first. We estimate that the first interferometers will see 2 - 3 events per year from black hole binaries with component masses of 10 - 15M\\odot, with a signal-to-noise ratio of about 3, in a network of detectors consisting of GEO, VIRGO and two LIGOs. It appears that other possible sources, including coalescing neutron stars, are unlikely to be detected by the early instruments. We also argue that relic gravitational waves may be discovered by space-based interferometers in the frequency interval 2 × 10-3 - 10-2 Hz, at a signal-to-noise ratio level of about 3.
Eccentric Black Hole Gravitational-wave Capture Sources in Galactic Nuclei: Distribution of Binary Parameters

NASA Astrophysics Data System (ADS)

Gondán, László; Kocsis, Bence; Raffai, Péter; Frei, Zsolt

2018-06-01

Mergers of binary black holes on eccentric orbits are among the targets for second-generation ground-based gravitational-wave detectors. These sources may commonly form in galactic nuclei due to gravitational-wave emission during close flyby events of single objects. We determine the distributions of initial orbital parameters for a population of these gravitational-wave sources. Our results show that the initial dimensionless pericenter distance systematically decreases with the binary component masses and the mass of the central supermassive black hole, and its distribution depends sensitively on the highest possible black hole mass in the nuclear star cluster. For a multi-mass black hole population with masses between 5 {M}ȯ and 80 {M}ȯ , we find that between ∼43–69% (68–94%) of 30 {M}ȯ –30 {M}ȯ (10 M ⊙–10 M ⊙) sources have an eccentricity greater than 0.1 when the gravitational-wave signal reaches 10 Hz, but less than ∼10% of the sources with binary component masses less than 30 {M}ȯ remain eccentric at this level near the last stable orbit (LSO). The eccentricity at LSO is typically between 0.005–0.05 for the lower-mass BHs, and 0.1–0.2 for the highest-mass BHs. Thus, due to the limited low-frequency sensitivity, the six currently known quasicircular LIGO/Virgo sources could still be compatible with this originally highly eccentric source population. However, at the design sensitivity of these instruments, the measurement of the eccentricity and mass distribution of merger events may be a useful diagnostic to identify the fraction of GW sources formed in this channel.
Evidence for Orbital Decay of RX J1914.4+2456: Gravitational Radiation and the Nature of the X-Ray Emission

NASA Technical Reports Server (NTRS)

Strohmayer, Tod E.; White, Nicholas E. (Technical Monitor)

2002-01-01

RX J1914.4+2456 is a candidate double-degenerate binary (AM CVn) with a putative 569 s orbital period. If this identification is correct, then it has one of the shortest binary orbital periods known, and gravitational radiation should drive the orbital evolution and mass transfer if the binary is semi-detached. Here we report the results of a coherent timing study of the archival ROSAT data for RX J1914.4+2456. We performed a phase coherent timing analysis using all five ROSAT observations spanning a four-year period. We demonstrate that all the data can be phase connected, and we show that the 1.756 mHz orbital frequency is increasing at a rate of 1.5 +/- 0.4 x 10(exp -17) Hz/s consistent with the expected loss of angular momentum from the binary system via gravitational radiation. In addition to providing evidence for the emission of gravitational waves, our measurement of the orbital v(dot) constrains models for the X-ray emission and the nature of the secondary. If stable mass accretion drives the X-ray flux, then a positive v(dot) is inconsistent with a degenerate donor. A helium burning dwarf is compatible if indeed such systems can have periods as short as that of RX J1914.4+2456, an open theoretical question. Our measurement of a positive v(dot) is consistent with the unipolar induction model of Wu et al. which does not require accretion to drive the X-ray flux. We discuss how future timing measurements of RX J1914.4+2456 (and systems like it) with for example, Chandra and XMM-Newton, can provide a unique probe of the interaction between mass loss and gravitational radiation. We also discuss the importance of such measurements in the context of gravitational wave detection from space, such as is expected in the future with the LISA mission.
Directed searches for continuous gravitational waves from spinning neutron stars in binary systems

NASA Astrophysics Data System (ADS)

Meadors, Grant David

2014-09-01

Gravitational wave detectors such as the Laser Interferometer Gravitational-wave Observatory (LIGO) seek to observe ripples in space predicted by General Relativity. Black holes, neutron stars, supernovae, the Big Bang and other sources can radiate gravitational waves. Original contributions to the LIGO effort are presented in this thesis: feedforward filtering, directed binary neutron star searches for continuous waves, and scientific outreach and education, as well as advances in quantum optical squeezing. Feedforward filtering removes extraneous noise from servo-controlled instruments. Filtering of the last science run, S6, improves LIGO's astrophysical range (+4.14% H1, +3.60% L1: +12% volume) after subtracting noise from auxiliary length control channels. This thesis shows how filtering enhances the scientific sensitivity of LIGO's data set during and after S6. Techniques for non-stationarity and verifying calibration and integrity may apply to Advanced LIGO. Squeezing is planned for future interferometers to exceed the standard quantum limit on noise from electromagnetic vacuum fluctuations; this thesis discusses the integration of a prototype squeezer at LIGO Hanford Observatory and impact on astrophysical sensitivity. Continuous gravitational waves may be emitted by neutron stars in low-mass X-ray binary systems such as Scorpius X-1. The TwoSpect directed binary search is designed to detect these waves. TwoSpect is the most sensitive of 4 methods in simulated data, projecting an upper limit of 4.23e-25 in strain, given a year-long data set at an Advanced LIGO design sensitivity of 4e-24 Hz. (-1/2). TwoSpect is also used on real S6 data to set 95% confidence upper limits (40 Hz to 2040 Hz) on strain from Scorpius X-1. A millisecond pulsar, X-ray transient J1751-305, is similarly considered. Search enhancements for Advanced LIGO are proposed. Advanced LIGO and fellow interferometers should detect gravitational waves in the coming decade. Methods in these thesis will benefit both the instrumental and analytical sides of observation.
The nature of spherical collapse and a study of black hole dynamics

NASA Astrophysics Data System (ADS)

Nampalliwar, Sourabh

Gravitational waves and singularities are two of the most significant predictions of General Relativity. Binary systems are the most promising sources of gravitational waves that are expected to be detected with the current ground-based and upcoming space-based gravitational wave detectors. During the merger of binary compact objects, an important stage is the plunge. A small part of the gravitational waveform, it marks the end of early inspiral and determines the quasinormal ringing (QNR) of the final product of the merger. It is also the part of the waveform where most of the gravitational energy is released. But, unlike early inspiral and late ringdown, it is poorly understood in terms of phenomenology. This thesis introduces a novel approach combining the Fourier domain Green's function in the particle perturbation approximation and a simple model to understand this crucial stage. The resulting understanding is successful in explaining QNR for a Schwarzschild black hole and opens a new approach to understanding binary inspiral. It holds the promise of a much improved understanding, and improved efficiency in making astrophysical estimates of gravitational wave source strength. Singularities are known to be the ultimate fate of all massive stars undergoing gravitational collapse. The cosmic censorship hypothesis predicts that all these singularities are generically covered by event horizons, i.e., all collapsing stars, if they result in a singularity, end up as black holes. Although several theoretical examples of non-hidden (naked) singularities have been found, the question of the genericity of naked singularities is far from settled. This thesis presents a study of the causal structure of spherically symmetric models of dust collapse and its perturbations to investigate the genericity of naked singularities.
Accuracy of Binary Black Hole waveforms for Advanced LIGO searches

NASA Astrophysics Data System (ADS)

Kumar, Prayush; Barkett, Kevin; Bhagwat, Swetha; Chu, Tony; Fong, Heather; Brown, Duncan; Pfeiffer, Harald; Scheel, Mark; Szilagyi, Bela

2015-04-01

Coalescing binaries of compact objects are flagship sources for the first direct detection of gravitational waves with LIGO-Virgo observatories. Matched-filtering based detection searches aimed at binaries of black holes will use aligned spin waveforms as filters, and their efficiency hinges on the accuracy of the underlying waveform models. A number of gravitational waveform models are available in literature, e.g. the Effective-One-Body, Phenomenological, and traditional post-Newtonian ones. While Numerical Relativity (NR) simulations provide for the most accurate modeling of gravitational radiation from compact binaries, their computational cost limits their application in large scale searches. In this talk we assess the accuracy of waveform models in two regions of parameter space, which have only been explored cursorily in the past: the high mass-ratio regime as well as the comparable mass-ratio + high spin regime.s Using the SpEC code, six q = 7 simulations with aligned-spins and lasting 60 orbits, and tens of q ∈ [1,3] simulations with high black hole spins were performed. We use them to study the accuracy and intrinsic parameter biases of different waveform families, and assess their viability for Advanced LIGO searches.
Samurai project: Verifying the consistency of black-hole-binary waveforms for gravitational-wave detection

NASA Astrophysics Data System (ADS)

Hannam, Mark; Husa, Sascha; Baker, John G.; Boyle, Michael; Brügmann, Bernd; Chu, Tony; Dorband, Nils; Herrmann, Frank; Hinder, Ian; Kelly, Bernard J.; Kidder, Lawrence E.; Laguna, Pablo; Matthews, Keith D.; van Meter, James R.; Pfeiffer, Harald P.; Pollney, Denis; Reisswig, Christian; Scheel, Mark A.; Shoemaker, Deirdre

2009-04-01

We quantify the consistency of numerical-relativity black-hole-binary waveforms for use in gravitational-wave (GW) searches with current and planned ground-based detectors. We compare previously published results for the (ℓ=2,|m|=2) mode of the gravitational waves from an equal-mass nonspinning binary, calculated by five numerical codes. We focus on the 1000M (about six orbits, or 12 GW cycles) before the peak of the GW amplitude and the subsequent ringdown. We find that the phase and amplitude agree within each code’s uncertainty estimates. The mismatch between the (ℓ=2,|m|=2) modes is better than 10-3 for binary masses above 60M⊙ with respect to the Enhanced LIGO detector noise curve, and for masses above 180M⊙ with respect to Advanced LIGO, Virgo, and Advanced Virgo. Between the waveforms with the best agreement, the mismatch is below 2×10-4. We find that the waveforms would be indistinguishable in all ground-based detectors (and for the masses we consider) if detected with a signal-to-noise ratio of less than ≈14, or less than ≈25 in the best cases.
Electromagnetic evidence that SSS17a is the result of a binary neutron star merger

NASA Astrophysics Data System (ADS)

Kilpatrick, C. D.; Foley, R. J.; Kasen, D.; Murguia-Berthier, A.; Ramirez-Ruiz, E.; Coulter, D. A.; Drout, M. R.; Piro, A. L.; Shappee, B. J.; Boutsia, K.; Contreras, C.; Di Mille, F.; Madore, B. F.; Morrell, N.; Pan, Y.-C.; Prochaska, J. X.; Rest, A.; Rojas-Bravo, C.; Siebert, M. R.; Simon, J. D.; Ulloa, N.

2017-12-01

Eleven hours after the detection of gravitational wave source GW170817 by the Laser Interferometer Gravitational-Wave Observatory and Virgo Interferometers, an associated optical transient, SSS17a, was identified in the galaxy NGC 4993. Although the gravitational wave data indicate that GW170817 is consistent with the merger of two compact objects, the electromagnetic observations provide independent constraints on the nature of that system. We synthesize the optical to near-infrared photometry and spectroscopy of SSS17a collected by the One-Meter Two-Hemisphere collaboration, finding that SSS17a is unlike other known transients. The source is best described by theoretical models of a kilonova consisting of radioactive elements produced by rapid neutron capture (the r-process). We conclude that SSS17a was the result of a binary neutron star merger, reinforcing the gravitational wave result.
Black Hole Mergers and Gravitational Waves: Opening the New Frontier

NASA Technical Reports Server (NTRS)

Centrella, Joan

2012-01-01

The final merger of two black holes produces a powerful burst of gravitational waves, emitting more energy than all the stars in the observable universe combined. Since these mergers take place in the regime of strong dynamical gravity, computing the gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For more than 30 years, scientists tried to simulate these mergers using the methods of numerical relativity. The resulting computer codes were plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. In the past several years, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will highlight these breakthroughs and the resulting 'gold rush' of new results that is revealing the dynamics of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.
Electromagnetic evidence that SSS17a is the result of a binary neutron star merger.

PubMed

Kilpatrick, C D; Foley, R J; Kasen, D; Murguia-Berthier, A; Ramirez-Ruiz, E; Coulter, D A; Drout, M R; Piro, A L; Shappee, B J; Boutsia, K; Contreras, C; Di Mille, F; Madore, B F; Morrell, N; Pan, Y-C; Prochaska, J X; Rest, A; Rojas-Bravo, C; Siebert, M R; Simon, J D; Ulloa, N

2017-12-22

Eleven hours after the detection of gravitational wave source GW170817 by the Laser Interferometer Gravitational-Wave Observatory and Virgo Interferometers, an associated optical transient, SSS17a, was identified in the galaxy NGC 4993. Although the gravitational wave data indicate that GW170817 is consistent with the merger of two compact objects, the electromagnetic observations provide independent constraints on the nature of that system. We synthesize the optical to near-infrared photometry and spectroscopy of SSS17a collected by the One-Meter Two-Hemisphere collaboration, finding that SSS17a is unlike other known transients. The source is best described by theoretical models of a kilonova consisting of radioactive elements produced by rapid neutron capture (the r-process). We conclude that SSS17a was the result of a binary neutron star merger, reinforcing the gravitational wave result. Copyright © 2017, American Association for the Advancement of Science.
Tidal interactions of inspiraling compact binaries

NASA Technical Reports Server (NTRS)

Bildsten, Lars; Cutler, Curt

1992-01-01

We discuss the tidal interaction in neutron star-neutron star and neutron star-black hole binaries and argue that they will not be tidally locked during the gravitational inspiral. More specifically, we show that, for inspiraling neutron stars of mass greater than about 1.2 solar mass, the shortest possible tidal synchronization time exceeds the gravitational decay time, so that the neutron star cannot be tidally locked prior to tidal disruption, regardless of its internal viscosity. For smaller mass neutron stars, an implausibly large kinematic viscosity - nearly the speed of light times the stellar radius - is required for tidal locking. We also argue that the mass transfer which occurs when the neutron star reaches the tidal radius will be unstable in neutron star-black hole binaries, and the instability will destroy the neutron star in a few orbital periods. The implications of our work for the detection of these sources by LIGO and other gravitational wave observatories and for the gamma-ray burst scenarios of Paczynski (1986, 1991) are discussed.
Distinguishing short duration noise transients in LIGO data to improve the PyCBC search for gravitational waves from high mass binary black hole mergers

NASA Astrophysics Data System (ADS)

Nitz, Alexander H.

2018-02-01

‘Blip glitches’ are a type of short duration transient noise in LIGO data. The cause for the majority of these is currently unknown. Short duration transient noise creates challenges for searches of the highest mass binary black hole systems, as standard methods of applying signal consistency, which look for consistency in the accumulated signal-to-noise of the candidate event, are unable to distinguish many blip glitches from short duration gravitational-wave signals due to similarities in their time and frequency evolution. We demonstrate a straightforward method, employed during Advanced LIGO’s second observing run, including the period of joint observation with the Virgo observatory, to separate the majority of this transient noise from potential gravitational-wave sources. This yields a ∼20% improvement in the detection rate of high mass binary black hole mergers (> 60 Mȯ ) for the PyCBC analysis.
Consistency of Post-Newtonian Waveforms with Numerical Relativity

NASA Technical Reports Server (NTRS)

Baker, John G.; vanMeter, James R.; McWilliams, Sean T.; Centrella, Joan; Kelly, Bernard J.

2007-01-01

General relativity predicts the gravitational radiation signatures of mergers of compact binaries,such as coalescing binary black hole systems. Derivations of waveform predictions for such systems are required for optimal scientific analysis of observational gravitational wave data, and have so far been achieved primarily with the aid of the post-Newtonian (PN) approximation. The quaIity of this treatment is unclear, however, for the important late inspiral portion. We derive late-inspiral wave forms via a complementary approach, direct numerical simulation of Einstein's equations, which has recently matured sufficiently for such applications. We compare waveform phasing from simulations covering the last approximately 14 cycles of gravitational radiation from an equal-mass binary system of nonspinning black holes with corresponding 3PN and 3.5PN waveforms. We find phasing agreement consistent with internal error estimates based in either approach, at the level of one radian over approximately 10 cycles. The result suggests that PN waveforms for this system are effective roughly until the system reaches its last stable orbit just prior to the final merger.
Inferring the post-merger gravitational wave emission from binary neutron star coalescences

NASA Astrophysics Data System (ADS)

Chatziioannou, Katerina; Clark, James Alexander; Bauswein, Andreas; Millhouse, Margaret; Littenberg, Tyson B.; Cornish, Neil

2017-12-01

We present a robust method to characterize the gravitational wave emission from the remnant of a neutron star coalescence. Our approach makes only minimal assumptions about the morphology of the signal and provides a full posterior probability distribution of the underlying waveform. We apply our method on simulated data from a network of advanced ground-based detectors and demonstrate the gravitational wave signal reconstruction. We study the reconstruction quality for different binary configurations and equations of state for the colliding neutron stars. We show how our method can be used to constrain the yet-uncertain equation of state of neutron star matter. The constraints on the equation of state we derive are complementary to measurements of the tidal deformation of the colliding neutron stars during the late inspiral phase. In the case of nondetection of a post-merger signal following a binary neutron star inspiral, we show that we can place upper limits on the energy emitted.
Consistency of Post-Newtonian Waveforms with Numerical Relativity

NASA Technical Reports Server (NTRS)

Baker, John G.; vanMeter, James R.; McWilliams, Sean T.; Cewntrella, Joan; Kelly, Bernard J.

2006-01-01

General relativity predicts the gravitational radiation signatures of mergers of compact binaries, such as coalescing binary black hole systems. Derivations of waveform predictions for such systems are required for optimal scientific analysis of observational gravitational wave data, and have so far been achieved primarily with the aid of the post-Newtonian (PN) approximation. The quality of this treatment is unclear, however, for the important late inspiral portion. We derive late-inspiral waveforms via a complementary approach, direct numerical simulation of Einstein's equations, which has recently matured sufficiently for such applications. We compare waveform phasing from simulations covering the last approximately 14 cycles of gravitational radiation from an equal-mass binary system of nonspinning black holes with the corresponding 3PN and 3.5PN orbital phasing. We find agreement consistent with internal error estimates based on either approach at the level of one radian over approximately 10 cycles. The result suggests that PN waveforms for this system are effective roughly until the system reaches its last stable orbit just prior to the final merger/
Binary Black Hole Mergers, Gravitational Waves, and LISA

NASA Technical Reports Server (NTRS)

Centrella, Joan; Baker, J.; Boggs, W.; Kelly, B.; McWilliams, S.; vanMeter, J.

2008-01-01

The final merger of comparable mass binary black holes is expected to be the strongest source of gravitational waves for LISA. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. We will present the results of new simulations of black hole mergers with unequal masses and spins, focusing on the gravitational waves emitted and the accompanying astrophysical "kicks." The magnitude of these kicks has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters.
Binary Black Holes: Mergers, Dynamics, and Waveforms

NASA Astrophysics Data System (ADS)

Centrella, Joan

2007-04-01

The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, data analysis, and astrophysics.
The expected spins of gravitational wave sources with isolated field binary progenitors

NASA Astrophysics Data System (ADS)

Zaldarriaga, Matias; Kushnir, Doron; Kollmeier, Juna A.

2018-01-01

We explore the consequences of dynamical evolution of field binaries composed of a primary black hole (BH) and a Wolf-Rayet (WR) star in the context of gravitational wave (GW) source progenitors. We argue, from general considerations, that the spin of the WR-descendent BH will be maximal in a significant number of cases due to dynamical effects. In other cases, the spin should reflect the natal spin of the primary BH which is currently theoretically unconstrained. We argue that the three currently published LIGO systems (GW150914, GW151226, LVT151012) suggest that this spin is small. The resultant effective spin distribution of gravitational wave sources should thus be bi-model if this classic GW progenitor channel is indeed dominant. While this is consistent with the LIGO detections thus far, it is in contrast to the three best-measured high-mass X-ray binary (HMXB) systems. A comparison of the spin distribution of HMXBs and GW sources should ultimately reveal whether or not these systems arise from similar astrophysical channels.

Bondi-Hoyle-Lyttleton Accretion onto Binaries

NASA Astrophysics Data System (ADS)

Antoni, Andrea; MacLeod, Morgan; Ramírez-Ruiz, Enrico

2018-01-01

Binary stars are not rare. While only close binary stars will eventually interact with one another, even the widest binary systems interact with their gaseous surroundings. The rates of accretion and the gaseous drag forces arising in these interactions are the key to understanding how these systems evolve. This poster examines accretion flows around a binary system moving supersonically through a background gas. We perform three-dimensional hydrodynamic simulations of Bondi-Hoyle-Lyttleton accretion using the adaptive mesh refinement code FLASH. We simulate a range of values of semi-major axis of the orbit relative to the gravitational focusing impact parameter of the pair. On large scales, gas is gravitationally focused by the center-of-mass of the binary, leading to dynamical friction drag and to the accretion of mass and momentum. On smaller scales, the orbital motion imprints itself on the gas. Notably, the magnitude and direction of the forces acting on the binary inherit this orbital dependence. The long-term evolution of the binary is determined by the timescales for accretion, slow down of the center-of-mass, and decay of the orbit. We use our simulations to measure these timescales and to establish a hierarchy between them. In general, our simulations indicate that binaries moving through gaseous media will slow down before the orbit decays.
Obituary: Bohdan Paczynski, 1940-2007

NASA Astrophysics Data System (ADS)

Spergel, David

2007-12-01

Bohdan Paczynski, Lyman Spitzer, Jr. Professor of Astrophysics, died at home in Princeton, New Jersey, on April 19, 2007. Born in Wilno, Poland (now Vilnius, Lithuania) on February 8, 1940, Paczynski's first encounter with astronomy was in 1954 when he visited Warsaw Astronomical Observatory in Ostrowok. Soon after his visit, he began a program of observing variable stars that led to his publishing his first paper, "Minima of Eclipsing Variables in 1954-56" at age 18. The study of binary star evolution would be a life-long interest. His highly cited 1971 review paper on "Evolutionary Processes in Close Binary Systems" still provides our framework for understanding binary stars. In his final year, Pacyznsk returned to his beloved variable stars and coauthored a paper with Warsaw University Observatory colleagues on "A Model of AW UMa," which has just appeared in Monthly Notices of the Royal Astronomical Society. In 1957, Pacyznski began studies at Warsaw University, where he worked with Stefan Piotrowski. After completing his Master's Degree, he traveled to the United States to become a night assistant at Lick Observatory. After his year in California, he returned to Poland to defend his PhD thesis in 1964 and to marry Hania Adamska, his lifelong companion. During the subsequent decade, Pacyznski's work had a profound impact on our understanding of stellar evolution. In between 1965 and 1967, Paczynski wrote a series of papers, "Evolution of Close Binaries I-V", that describe how nearby neighbors alter the evolution of stars. These papers were the basis for his doctor habilatus, a higher degree remarkably earned at age 27. He then spent a year as a Fellow at the University of Colorado's Joint Institute for Laboratory Astrophysics. Primarily during his year in Boulder, he developed "The Paczynski Code". Using this code, Paczynski wrote a series of papers that showed that the cores of stars between 3 and 7 times the mass of the Sun converge to similar behavior. These stars end their life as planetary nebulae and leave behind cooling white dwarfs. This code was made publicly available and was widely used by the international community. The code is still in circulation—most recently, it was made available as a CD in Carl Hansen, et al's 2004 book on Stellar Interiors. In 1969, Paczynski returned to the Institute of Astronomy as an assistant professor. He would be promoted to associate in 1974 and to professor in 1979. In the late 1970s and early 1980s, Paczynski and his collaborators wrote a number of influential papers on the properties of accretion disks around black holes. These papers showed that geometrically thick disks of gas could radiate at super-Eddington rates. These "polish donut" models are important tools in our understanding of quasars and accreting X-ray sources. In December 1981, martial law was declared in Poland. Paczynski and his family were visiting the California Institute of Technology at the time, where he was spending the year as a Fairchild Fellow. Faced with the decaying political situation in Poland, Pacynski decided to stay in the United States. He quickly received offers from many leading universities. In 1982, he joined the Princeton faculty as a Professor in the Department of Astrophysical Sciences. In 1989, Paczynski became the first Lyman Spitzer, Jr. Professor of Theoretical Astrophysics. While not able to visit Poland until the collapse of communism in 1989, Paczynski invited many of his Polish colleagues to visit Princeton and the USA. Throughout his career, he was a vital link between US and Polish astronomy and was an important mentor for many Polish and US astronomers. At Princeton, Pacynski's interests turned to gravitational lensing and its astrophysical applications. The nature of the dark matter that makes up more than 80% of the mass of our Galaxy is one of the great mysteries of astronomy and physics. Many astronomers suspected that low mass stars could be the dark matter. Paczynski recognized that these stars would act as foreground gravitational lenses and amplify the light from background stars. In a subsequent paper with Princeton graduate student Shude Mao, Paczynski noted that planets would produce a distinctive microlensing signal. Paczynski's gravitational-lensing papers inspired a host of projects that used large CCDs to study the variable universe. Working with colleagues at Warsaw University and the Carnegie Institution, Paczynski and his Optical Gravitational Lensing Experiment (OGLE) collaborators detected the first microlensing events towards the galactic bulge. While the microlensing surveys detected the expected number of events when looking toward the galactic center, very few events were seen in the direction of the Magellanic Clouds. This low event rate implies that "Jupiters" or low mass stars do not make up most of the mass of our Galaxy and strengthens the case that a new subatomic particle makes up most of the dark matter. Last year, the OGLE collaboration produced its most dramatic result: the first detection of terrestrial planets around another star. Searches using other techniques have only been able to detect Jupiter-like planets and have not been sensitive enough to detect rocky planets like our own Earth. By following up on OGLE detections in nearly real time with other telescopes, Paczynski and his collaborators made a major step along the path towards find a planet like Earth around a nearby star. Their initial results imply they are common and that many nearby stars harbor rocky planets. OGLE's variability survey has also uncovered a host of exciting astronomical objects. OGLE discoveries include transiting planets, RR Lyrae stars, and eclipsing binaries. Paczynski recognized the potential value of eclipsing binaries for establishing the distance scale and for testing stellar models. Paczysnki was a very early, persistent, and effective advocate of the idea that Gamma Ray Bursts were extragalactic. This idea ran counter to conventional wisdom and implied that the energy released in gamma-ray bursts greatly exceeded the energy released in optical light in supernova explosions. Many high-energy astrophysicists found Paczynski's proposal absurd; however, Paczynski emphasized that the astronomical evidence all pointed towards these powerful explosions coming from outside our Galaxy. With improved data from a new generation of high-energy satellites, observers were able to confirm the extragalactic nature of gamma-ray bursts. Paczynski's heresy has become our firmly established understanding. The astronomy community recognized Bohdan Paczynski with many honors and awards. The American Astronomical Society awarded him the Heinemann Prize and its highest honor, the Russell Prize in 2006. The Royal Astronomical Society recognized his contributions with the Eddington Medal (1987), the George Darwin Lectureship (1996), and its Gold Medal (1999). He won the Astronomical Society of Pacific's Bruce Gold Medal (2002). He was a member of the Polish Academy of Sciences and a foreign member of both the National Academy of Sciences and the Royal Academy of Sciences. Diagnosed three years ago with inoperable brain cancer, Paczynski bravely fought on and continued his intellectual activities. With his life prolonged by an experimental treatment, he spent his valuable time with his family, his students, and his colleagues. He continued to be a regular presence at department coffee, where he offered wise and witty insights into a wide range of topics in astrophysics. Paczynski is survived by his wife, Hanka, his daughter, Agnieszka, his son, Martin, and a grandchild. Paczynski was generous with his time and his thoughts, and colleagues and students sought his scientific insight and personal wisdom. His good spirits during his final struggle was an inspiration to all around him. His conduct as a scientist and as a human being was distinguished by unfailing politeness, good sense, and personal integrity. I would like to thank Bruce Draine and Jeremiah Ostriker for their assistance in writing this obituary. The photograph is by Robert P. Matthews, Princeton University (1989).
Dependence of Microlensing on Source Size and Lens Mass

NASA Astrophysics Data System (ADS)

Congdon, A. B.; Keeton, C. R.

2007-11-01

In gravitational lensed quasars, the magnification of an image depends on the configuration of stars in the lensing galaxy. We study the statistics of the magnification distribution for random star fields. The width of the distribution characterizes the amount by which the observed magnification is likely to differ from models in which the mass is smoothly distributed. We use numerical simulations to explore how the width of the magnification distribution depends on the mass function of stars, and on the size of the source quasar. We then propose a semi-analytic model to describe the distribution width for different source sizes and stellar mass functions.
Distinguishing boson stars from black holes and neutron stars from tidal interactions in inspiraling binary systems

NASA Astrophysics Data System (ADS)

Sennett, Noah; Hinderer, Tanja; Steinhoff, Jan; Buonanno, Alessandra; Ossokine, Serguei

2017-07-01

Binary systems containing boson stars—self-gravitating configurations of a complex scalar field—can potentially mimic black holes or neutron stars as gravitational-wave sources. We investigate the extent to which tidal effects in the gravitational-wave signal can be used to discriminate between these standard sources and boson stars. We consider spherically symmetric boson stars within two classes of scalar self-interactions: an effective-field-theoretically motivated quartic potential and a solitonic potential constructed to produce very compact stars. We compute the tidal deformability parameter characterizing the dominant tidal imprint in the gravitational-wave signals for a large span of the parameter space of each boson star model, covering the entire space in the quartic case, and an extensive portion of interest in the solitonic case. We find that the tidal deformability for boson stars with a quartic self-interaction is bounded below by Λmin≈280 and for those with a solitonic interaction by Λmin≈1.3 . We summarize our results as ready-to-use fits for practical applications. Employing a Fisher matrix analysis, we estimate the precision with which Advanced LIGO and third-generation detectors can measure these tidal parameters using the inspiral portion of the signal. We discuss a novel strategy to improve the distinguishability between black holes/neutrons stars and boson stars by combining tidal deformability measurements of each compact object in a binary system, thereby eliminating the scaling ambiguities in each boson star model. Our analysis shows that current-generation detectors can potentially distinguish boson stars with quartic potentials from black holes, as well as from neutron-star binaries if they have either a large total mass or a large (asymmetric) mass ratio. Discriminating solitonic boson stars from black holes using only tidal effects during the inspiral will be difficult with Advanced LIGO, but third-generation detectors should be able to distinguish between binary black holes and these binary boson stars.
Modeling the Complete Gravitational Wave Spectrum of Neutron Star Mergers.

PubMed

Bernuzzi, Sebastiano; Dietrich, Tim; Nagar, Alessandro

2015-08-28

In the context of neutron star mergers, we study the gravitational wave spectrum of the merger remnant using numerical relativity simulations. Postmerger spectra are characterized by a main peak frequency f2 related to the particular structure and dynamics of the remnant hot hypermassive neutron star. We show that f(2) is correlated with the tidal coupling constant κ(2)^T that characterizes the binary tidal interactions during the late-inspiral merger. The relation f(2)(κ(2)^T) depends very weakly on the binary total mass, mass ratio, equation of state, and thermal effects. This observation opens up the possibility of developing a model of the gravitational spectrum of every merger unifying the late-inspiral and postmerger descriptions.
The confrontation between general relativity and experiment

NASA Technical Reports Server (NTRS)

Will, C. M.

1980-01-01

Experiments that test the foundations of gravitation theory in terms of the Einstein equivalence principle are discussed along with solar system tests of general relativity at the post-Newtonian level. These include classical (light-deflection, time delay and perihelion shift) tests as well as tests of the strong equivalence principle. The binary pulsar is discussed as an extra-solar-system gravitational testing ground, and attention is given to the multipolarity of the waves and the amount of radiation damping. The mass function, periastron shift, redshift-Doppler parameter and rate of change of the orbit period (Pb) of the binary pulsar are also considered, and it is suggested that the measurement of Pb represents the first observation of the effects of gravitational radiation.
The late inspiral of supermassive black hole binaries with circumbinary gas discs in the LISA band

NASA Astrophysics Data System (ADS)

Tang, Yike; Haiman, Zoltán; MacFadyen, Andrew

2018-05-01

We present the results of 2D, moving-mesh, viscous hydrodynamical simulations of an accretion disc around a merging supermassive black hole binary (SMBHB). The simulation is pseudo-Newtonian, with the BHs modelled as point masses with a Paczynski-Wiita potential, and includes viscous heating, shock heating, and radiative cooling. We follow the gravitational inspiral of an equal-mass binary with a component mass Mbh = 106 M⊙ from an initial separation of 60rg (where rg ≡ GMbh/c2 is the gravitational radius) to the merger. We find that a central, low-density cavity forms around the binary, as in previous work, but that the BHs capture gas from the circumbinary disc and accrete efficiently via their own minidiscs, well after their inspiral outpaces the viscous evolution of the disc. The system remains luminous, displaying strong periodicity at twice the binary orbital frequency throughout the entire inspiral process, all the way to the merger. In the soft X-ray band, the thermal emission is dominated by the inner edge of the circumbinary disc with especially clear periodicity in the early inspiral. By comparison, harder X-ray emission is dominated by the minidiscs, and the light curve is initially more noisy but develops a clear periodicity in the late inspiral stage. This variability pattern should help identify the electromagnetic counterparts of SMBHBs detected by the space-based gravitational-wave detector LISA.
MONTE CARLO POPULATION SYNTHESIS OF POST-COMMON-ENVELOPE WHITE DWARF BINARIES AND TYPE Ia SUPERNOVA RATE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ablimit, Iminhaji; Maeda, Keiichi; Li, Xiang-Dong

Binary population synthesis (BPS) studies provide a comprehensive way to understand the evolution of binaries and their end products. Close white dwarf (WD) binaries have crucial characteristics for examining the influence of unresolved physical parameters on binary evolution. In this paper, we perform Monte Carlo BPS simulations, investigating the population of WD/main-sequence (WD/MS) binaries and double WD binaries using a publicly available binary star evolution code under 37 different assumptions for key physical processes and binary initial conditions. We considered different combinations of the binding energy parameter ( λ {sub g}: considering gravitational energy only; λ {sub b}: considering bothmore » gravitational energy and internal energy; and λ {sub e}: considering gravitational energy, internal energy, and entropy of the envelope, with values derived from the MESA code), CE efficiency, critical mass ratio, initial primary mass function, and metallicity. We find that a larger number of post-CE WD/MS binaries in tight orbits are formed when the binding energy parameters are set by λ {sub e} than in those cases where other prescriptions are adopted. We also determine the effects of the other input parameters on the orbital periods and mass distributions of post-CE WD/MS binaries. As they contain at least one CO WD, double WD systems that evolved from WD/MS binaries may explode as type Ia supernovae (SNe Ia) via merging. In this work, we also investigate the frequency of two WD mergers and compare it to the SNe Ia rate. The calculated Galactic SNe Ia rate with λ = λ {sub e} is comparable to the observed SNe Ia rate, ∼8.2 × 10{sup 5} yr{sup 1} – ∼4 × 10{sup 3} yr{sup 1} depending on the other BPS parameters, if a DD system does not require a mass ratio higher than ∼0.8 to become an SNe Ia. On the other hand, a violent merger scenario, which requires the combined mass of two CO WDs ≥ 1.6 M {sub ⊙} and a mass ratio >0.8, results in a much lower SNe Ia rate than is observed.« less
Formation of close binary black holes merging due to gravitational-wave radiation

NASA Astrophysics Data System (ADS)

Tutukov, A. V.; Cherepashchuk, A. M.

2017-10-01

The conditions for the formation of close-binary black-hole systems merging over the Hubble time due to gravitational-wave radiation are considered in the framework of current ideas about the evolution of massive close-binary systems. The original systems whose mergers were detected by LIGO consisted of main-sequence stars with masses of 30-100 M ⊙. The preservation of the compactness of a binary black hole during the evolution of its components requires either the formation of a common envelope, probably also with a low initial abundance of metals, or the presence of a "kick"—a velocity obtained during a supernova explosion accompanied by the formation of a black hole. In principle, such a kick can explain the relatively low frequency of mergers of the components of close-binary stellar black holes, if the characteristic speed of the kick exceeds the orbital velocities of the system components during the supernova explosion. Another opportunity for the components of close-binary systems to approach each other is related to their possible motion in a dense molecular cloud.
Exploring properties of high-density matter through remnants of neutron-star mergers

NASA Astrophysics Data System (ADS)

Bauswein, Andreas; Stergioulas, Nikolaos; Janka, Hans-Thomas

2016-03-01

Remnants of neutron-star mergers are essentially massive, hot, differentially rotating neutron stars, which are initially strongly oscillating. As such they represent a unique probe for high-density matter because the oscillations are detectable via gravitational-wave measurements and are strongly dependent on the equation of state. The impact of the equation of state for instance is apparent in the frequency of the dominant oscillation mode of the remnant. For a fixed total binary mass a tight relation between the dominant postmerger oscillation frequency and the radii of nonrotating neutron stars exists. Inferring observationally the dominant postmerger frequency thus determines neutron star radii with high accuracy of the order of a few hundred meters. By considering symmetric and asymmetric binaries of the same chirp mass, we show that the knowledge of the binary mass ratio is not critical for this kind of radius measurements. We perform simulations which show that initial intrinsic neutron star rotation is unlikely to affect this method of constraining the high-density equation of state. We also summarize different possibilities about how the postmerger gravitational-wave emission can be employed to deduce the maximum mass of nonrotating neutron stars. We clarify the nature of the three most prominent features of the postmerger gravitational-wave spectrum and argue that the merger remnant can be considered to be a single, isolated, self-gravitating object that can be described by concepts of asteroseismology. We sketch how the consideration of the strength of secondary gravitational-wave peaks leads to a classification scheme of the gravitational-wave emission and postmerger dynamics. The understanding of the different mechanisms shaping the gravitational-wave signal yields a physically motivated analytic model of the gravitational-wave emission, which may form the basis for template-based gravitational-wave data analysis. We explore the observational consequences of a scenario of two families of compact stars including hadronic and quark matter stars. We find that this scenario leaves a distinctive imprint on the postmerger gravitational-wave signal. In particular, a strong discontinuity in the dominant postmerger frequency as function of the total mass will be a strong indication for two families of compact stars.
Connecting Numerical Relativity and Data Analysis of Gravitational Wave Detectors

NASA Astrophysics Data System (ADS)

Shoemaker, Deirdre; Jani, Karan; London, Lionel; Pekowsky, Larne

Gravitational waves deliver information in exquisite detail about astrophysical phenomena, among them the collision of two black holes, a system completely invisible to the eyes of electromagnetic telescopes. Models that predict gravitational wave signals from likely sources are crucial for the success of this endeavor. Modeling binary black hole sources of gravitational radiation requires solving the Einstein equations of General Relativity using powerful computer hardware and sophisticated numerical algorithms. This proceeding presents where we are in understanding ground-based gravitational waves resulting from the merger of black holes and the implications of these sources for the advent of gravitational-wave astronomy.
Statistics of Microlensing Caustic Crossings in Q 2237+0305: Peculiar Velocity of the Lens Galaxy and Accretion Disk Size

NASA Astrophysics Data System (ADS)

Mediavilla, E.; Jimenez-Vicente, J.; Muñoz, J. A.; Mediavilla, T.; Ariza, O.

2015-01-01

We use the statistics of caustic crossings induced by microlensing in the lens system Q 2237+0305 to study the lens galaxy peculiar velocity. We calculate the caustic crossing rates for a comprehensive family of stellar mass functions and find a dependence of the average number of caustic crossings with the effective transverse velocity and the average mass, < n > \\propto {veff / \\sqrt{< m > }}, equivalent to the theoretical prediction for the case of microlenses with identical masses. We explore the possibilities of the method to measure v eff using the ~12 yr of Optical Gravitational Lensing Experiment monitoring of the four images of Q 2237+0305. To determine a lower limit for v eff, we count, conservatively, a single caustic crossing for each one of the four high magnification events identified in the literature (plus one additional proposed by us) obtaining veff ≳ 240\\sqrt{< m > /0.17 M_⊙ } km s-1 at 68% of confidence. From this value and the average FWHM of the four high magnification events, we obtain a lower limit of rs ≳ 1.4 \\sqrt{< m > /0.17 M_⊙ } light-days for the radius of the source (rs = FWHM/2.35). Tentative identification of three additional caustic crossing events leads to estimates of veff≃ (493+/- 246)\\sqrt{< m > /0.17 M_⊙ } km s-1 for the effective transverse velocity and of rs ≃ (2.7+/- 1.3)\\sqrt{< m > /0.17 M_⊙ } light-days for the source size. The estimated transverse peculiar velocity of the galaxy is vt ≃ (429+/- 246)\\sqrt{< m > /0.17 M_⊙ } km s-1.
Binary Black Holes and Gravitational Waves

NASA Technical Reports Server (NTRS)

Centrella, Joan

2007-01-01

The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LIGO and LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these wave patterns. For more than 30 years, scientists have tried to compute these wave patterns. However, their computer codes have been plagued by problems that caused them to crash. This situation has changed dramatically in the past 2 years, with a series of amazing breakthroughs. This discussion examines these gravitational patterns, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. The focus is on recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by the space-based gravitational wave detector LISA.
Calculating Gravitational Wave Signature from Binary Black Hole Mergers

NASA Technical Reports Server (NTRS)

Centrella, Joan M.

2003-01-01

Calculations of the final merger stage of binary black hole evolution can only be carried out using full scale numerical relativity simulations. We review the status of these calculations, highlighting recent progress and current challenges.
Getting Astrophysical Information from LISA Data

NASA Technical Reports Server (NTRS)

Stebbins, R. T.; Bender, P. L.; Folkner, W. M.

1997-01-01

Gravitational wave signals from a large number of astrophysical sources will be present in the LISA data. Information about as many sources as possible must be estimated from time series of strain measurements. Several types of signals are expected to be present: simple periodic signals from relatively stable binary systems, chirped signals from coalescing binary systems, complex waveforms from highly relativistic binary systems, stochastic backgrounds from galactic and extragalactic binary systems and possibly stochastic backgrounds from the early Universe. The orbital motion of the LISA antenna will modulate the phase and amplitude of all these signals, except the isotropic backgrounds and thereby give information on the directions of sources. Here we describe a candidate process for disentangling the gravitational wave signals and estimating the relevant astrophysical parameters from one year of LISA data. Nearly all of the sources will be identified by searching with templates based on source parameters and directions.
Evolution of double white dwarf binaries undergoing direct-impact accretion: Implications for gravitational wave astronomy

NASA Astrophysics Data System (ADS)

Kremer, Kyle; Breivik, Katelyn; Larson, Shane L.; Kalogera, Vassiliki

2017-01-01

For close double white dwarf binaries, the mass-transfer phenomenon known as direct-impact accretion (when the mass transfer stream impacts the accretor directly rather than forming a disc) may play a pivotal role in the long-term evolution of the systems. In this analysis, we explore the long-term evolution of white dwarf binaries accreting through direct-impact and explore implications of such systems to gravitational wave astronomy. We cover a broad range of parameter space which includes initial component masses and the strength of tidal coupling, and show that these systems, which lie firmly within the LISA frequency range, show strong negative chirps which can last as long as several million years. Detections of double white dwarf systems in the direct-impact phase by detectors such as LISA would provide astronomers with unique ways of probing the physics governing close compact object binaries.
Obtaining gravitational waves from inspiral binary systems using LIGO data

NASA Astrophysics Data System (ADS)

Antelis, Javier M.; Moreno, Claudia

2017-01-01

The discovery of the astrophysical events GW150926 and GW151226 has experimentally confirmed the existence of gravitational waves (GW) and has demonstrated the existence of binary stellar-mass black hole systems. This finding marks the beginning of a new era that will reveal unexpected features of our universe. This work presents a basic insight to the fundamental theory of GW emitted by inspiral binary systems and describes the scientific and technological efforts developed to measure these waves using the interferometer-based detector called LIGO. Subsequently, the work presents a comprehensive data analysis methodology based on the matched filter algorithm, which aims to recovery GW signals emitted by inspiral binary systems of astrophysical sources. This algorithm was evaluated with freely available LIGO data containing injected GW waveforms. Results of the experiments performed to assess detection accuracy showed the recovery of 85% of the injected GW.
Rapid formation of supermassive black hole binaries in galaxy mergers with gas.

PubMed

Mayer, L; Kazantzidis, S; Madau, P; Colpi, M; Quinn, T; Wadsley, J

2007-06-29

Supermassive black holes (SMBHs) are a ubiquitous component of the nuclei of galaxies. It is normally assumed that after the merger of two massive galaxies, a SMBH binary will form, shrink because of stellar or gas dynamical processes, and ultimately coalesce by emitting a burst of gravitational waves. However, so far it has not been possible to show how two SMBHs bind during a galaxy merger with gas because of the difficulty of modeling a wide range of spatial scales. Here we report hydrodynamical simulations that track the formation of a SMBH binary down to scales of a few light years after the collision between two spiral galaxies. A massive, turbulent, nuclear gaseous disk arises as a result of the galaxy merger. The black holes form an eccentric binary in the disk in less than 1 million years as a result of the gravitational drag from the gas rather than from the stars.
Nonlinear gravitational recoil from the mergers of precessing black-hole binaries

NASA Astrophysics Data System (ADS)

Lousto, Carlos O.; Zlochower, Yosef

2013-04-01

We present results from an extensive study of 88 precessing, equal-mass black-hole binaries with large spins (83 with intrinsic spins |S→i/mi2| of 0.8 and 5 with intrinsic spins of 0.9), and use these data to model new nonlinear contributions to the gravitational recoil imparted to the merged black hole. We find a new effect, the cross kick, that enhances the recoil for partially aligned binaries beyond the hangup kick effect. This has the consequence of increasing the probabilities of recoils larger than 2000kms-1 by nearly a factor of 2, and consequently, of black holes getting ejected from galaxies, as well as the observation of large differential redshifts/blueshifts in the cores of recently merged galaxies.
Exploring stellar evolution with gravitational-wave observations

NASA Astrophysics Data System (ADS)

Dvorkin, Irina; Uzan, Jean-Philippe; Vangioni, Elisabeth; Silk, Joseph

2018-05-01

Recent detections of gravitational waves from merging binary black holes opened new possibilities to study the evolution of massive stars and black hole formation. In particular, stellar evolution models may be constrained on the basis of the differences in the predicted distribution of black hole masses and redshifts. In this work we propose a framework that combines galaxy and stellar evolution models and use it to predict the detection rates of merging binary black holes for various stellar evolution models. We discuss the prospects of constraining the shape of the time delay distribution of merging binaries using just the observed distribution of chirp masses. Finally, we consider a generic model of primordial black hole formation and discuss the possibility of distinguishing it from stellar-origin black holes.

Gravitational radiation quadrupole formula is valid for gravitationally interacting systems

NASA Technical Reports Server (NTRS)

Walker, M.; Will, C. M.

1980-01-01

An argument is presented for the validity of the quadrupole formula for gravitational radiation energy loss in the far field of nearly Newtonian (e.g., binary stellar) systems. This argument differs from earlier ones in that it determines beforehand the formal accuracy of approximation required to describe gravitationally self-interacting systems, uses the corresponding approximate equation of motion explicitly, and evaluates the appropriate asymptotic quantities by matching along the correct space-time light cones.
Revealing stellar brightness profiles by means of microlensing fold caustics

NASA Astrophysics Data System (ADS)

Dominik, M.

2004-09-01

With a handful of measurements of limb-darkening coefficients, galactic microlensing has already proven to be a powerful technique for studying atmospheres of distant stars. Survey campaigns such as OGLE-III are capable of providing ~10 suitable target stars per year that undergo microlensing events involving passages over the caustic created by a binary lens, which last from a few hours to a few days and allow us to resolve the stellar atmosphere by frequent broad-band photometry. For a caustic exit lasting 12 h and a photometric precision of 1.5 per cent, a moderate sampling interval of 30 min (corresponding to ~25-30 data points) is sufficient for providing a reliable measurement of the linear limb-darkening coefficient Γ with an uncertainty of ~8 per cent, which reduces to ~3 per cent for a reduced sampling interval of 6 min for the surroundings of the end of the caustic exit. While some additional points over the remaining parts of the light curve are highly valuable, a denser sampling in these regions provides little improvement. Unless an accuracy of less than 5 per cent is desired, limb-darkening coefficients for several filters can be obtained or observing time can be spent on other targets during the same night. The adoption of an inappropriate stellar brightness profile as well as the effect of acceleration between source and caustic yield distinguishable characteristic systematics in the model residuals. Acceleration effects are unlikely to affect the light curve significantly for most events, although a free acceleration parameter blurs the limb-darkening measurement if the passage duration cannot be accurately determined.
COSMIC probes into compact binary formation and evolution

NASA Astrophysics Data System (ADS)

Breivik, Katelyn

2018-01-01

The population of compact binaries in the galaxy represents the final state of all binaries that have lived up to the present epoch. Compact binaries present a unique opportunity to probe binary evolution since many of the interactions binaries experience can be imprinted on the compact binary population. By combining binary evolution simulations with catalogs of observable compact binary systems, we can distill the dominant physical processes that govern binary star evolution, as well as predict the abundance and variety of their end products.The next decades herald a previously unseen opportunity to study compact binaries. Multi-messenger observations from telescopes across all wavelengths and gravitational-wave observatories spanning several decades of frequency will give an unprecedented view into the structure of these systems and the composition of their components. Observations will not always be coincident and in some cases may be separated by several years, providing an avenue for simulations to better constrain binary evolution models in preparation for future observations.I will present the results of three population synthesis studies of compact binary populations carried out with the Compact Object Synthesis and Monte Carlo Investigation Code (COSMIC). I will first show how binary-black-hole formation channels can be understood with LISA observations. I will then show how the population of double white dwarfs observed with LISA and Gaia could provide a detailed view of mass transfer and accretion. Finally, I will show that Gaia could discover thousands black holes in the Milky Way through astrometric observations, yielding view into black-hole astrophysics that is complementary to and independent from both X-ray and gravitational-wave astronomy.
Sub-radian-accuracy gravitational waveforms of coalescing binary neutron stars in numerical relativity

NASA Astrophysics Data System (ADS)

Kiuchi, Kenta; Kawaguchi, Kyohei; Kyutoku, Koutarou; Sekiguchi, Yuichiro; Shibata, Masaru; Taniguchi, Keisuke

2017-10-01

Extending our previous studies, we perform high-resolution simulations of inspiraling binary neutron stars in numerical relativity. We thoroughly carry through a convergence study in our currently available computational resources with the smallest grid spacing of ≈63 - 86 meter for the neutron-star radius 10.9-13.7 km. The estimated total error in the gravitational-wave phase is of order 0.1 rad for the total phase of ≳210 rad in the last ˜15 - 16 inspiral orbits. We then compare the waveforms (without resolution extrapolation) with those calculated by the latest effective-one-body formalism (tidal SEOBv2 model referred to as TEOB model). We find that for any of our models of binary neutron stars, the waveforms calculated by the TEOB formalism agree with the numerical-relativity waveforms up to ≈3 ms before the peak of the gravitational-wave amplitude is reached: For this late inspiral stage, the total phase error is ≲0.1 rad . Although the gravitational waveforms have an inspiral-type feature for the last ˜3 ms , this stage cannot be well reproduced by the current TEOB formalism, in particular, for neutron stars with large tidal deformability (i.e., lager radius). The reason for this is described.
Hans A. Bethe Prize: Cosmic Collisions Online - Compact Binary Mergers, Gravitational Waves and Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Shapiro, Stuart

2017-01-01

Hans A. Bethe elucidated our understanding of the fundamental forces of Nature by exploring and explaining countless phenomena occurring in nuclear laboratories and in stars. With the dawn of gravitational wave astronomy we now can probe compact binary mergers - Nature's cosmic collision experiments - to deepen our understanding, especially where strong-field gravitation is involved. In addition to gravitational waves, some mergers are likely to generate observable electromagnetic and/or neutrino radiation, heralding a new era of multimessenger astronomy. Robust numerical algorithms now allow us to simulate these events in full general relativity on supercomputers. We will describe some recent magnetohydrodynamic simulations that show how binary black hole-neutron star and neutron star-neutron star mergers can launch jets, lending support to the idea that such mergers could be the engines that power short gamma-ray bursts. We will also show how the magnetorotational collapse of very massive stars to spinning black holes immersed in magnetized accretion disks can launch jets as well, reinforcing the belief that such ``collapsars'' are the progenitors of long gamma-ray bursts. Computer-generated movies highlighting some of these simulations will be shown. We gratefully acknowledge support from NSF Grants 1300903 and 1602536 and NASA Grant NNX13AH44G.
Rotating and Binary Stars in General Relativit

NASA Astrophysics Data System (ADS)

Shapiro, Stuart

The inspiral and coalescence of compact binary stars is one of the most challenging problems in theoretical astrophysics. Only recently have advances in numerical relativity made it possible to explore this topic in full general relativity (GR). The mergers of compact binaries have important consequences for the detection of gravitational waves. In addition, the coalescence of binary neutron stars (NSNSs) and binary black-hole neutron stars (BHNSs) may hold the key for resolving other astrophysical puzzles, such as the origin of short-hard gamma-ray bursts (GRBs). While simulations of these systems in full GR are now possible, only the most idealized treatments have been performed to date. More detailed physics, including magnetic fields, black hole spin, a realistic hot, nuclear equation of state and neutrino transport must be incorporated. Only then will we be able to identify reliably future sources that may be detected simultaneously in gravitational waves and as GRBs. Likewise, the coalescence of binary black holes (BHBHs) is now a solved problem in GR, but only in vacuum. Simulating the coalescence of BHBHs in the gaseous environments likely to be found in nearby galaxy cores or in merging galaxies is crucial to identifying an electromagnetic signal that might accompany the gravitational waves produced during the merger. The coalescence of a binary white dwarf-neutron star (WDNS) has only recently been treated in GR, but GR is necessary to explore tidal disruption scenarios in which the capture of WD debris by the NS may lead to catastrophic collapse. Alternatively, the NS may survive and the merger might result in the formation of pulsar planets. The stability of rotating neutron stars in these and other systems has not been fully explored in GR, and the final fate of unstable stars has not been determined in many cases, especially in the presence of magnetic fields and differential rotation. These systems will be probed observationally by current NASA instruments, such as HST, CHANDRA, SWIFT and FERMI, and by future NASA detectors, such as NuStar, ASTRO-H, GEMS, JWST, and, possibly, GEN-X and SGO (a Space-Based Gravitational-Wave Observatory). Treating all of these phenomena theoretically requires the same computational machinery: a fully relativistic code that simultaneously solves Einstein s equations for the gravitational field, Maxwell s equations for the electromagnetic field and the equations of relativistic magnetohydrodynamics for the plasma, all in three spatial dimensions plus time. Recent advances we have made in constructing such a code now make it possible for us to solve these fundamental, closely related computational problems, some for the first time.
LIGO Discovers the Merger of Two Black Holes

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-02-01

Big news: the Laser Interferometer Gravitational-Wave Observatory (LIGO) has detected its first gravitational-wave signal! Not only is the detection of this signal a major technical accomplishment and an exciting confirmation of general relativity, but it also has huge implications for black-hole astrophysics.What did LIGO see?LIGO is designed to detect the ripples in space-time created by two massive objects orbiting each other. These waves can reach observable amplitudes when a binary system consisting of two especially massive objects i.e., black holes or neutron stars reach the end of their inspiral and merge.LIGO has been unsuccessfully searching for gravitational waves since its initial operations in 2002, but a recent upgrade in its design has significantly increased its sensitivity and observational range. The first official observing run of Advanced LIGO began 18 September 2015, but the instruments were up and running in engineering mode several weeks before that. And it was in this time frame before official observing even began! that LIGO spotted its first gravitational wave signal: GW150914.One of LIGOs two detection sites, located near Hanford in eastern Washington. [LIGO]The signal, detected on 14 September, 2015, provides astronomers with a remarkable amount of information about the merger that caused it. From the detection, the LIGO team has extracted the masses of the two black holes that merged, 36+5-4 and 29+4-4 solar masses, as well as the mass of the final black hole formed by the merger, ~62 solar masses. The team also determined that the merger happened roughly a billion light-years away (at a redshift of z~0.1), and the direction of the signal was localized to an area of ~600 square degrees (roughly 1% of the sky).Why is this detection a big deal?This is the firstdirect detection of gravitational waves, providing spectacular further confirmation of Einsteins theory of general relativity. But the implications of GW150914 go far beyond this confirmation. This detection is a huge deal for astrophysics because its the first direct evidence weve had that:Heavy stellar-mass black holes exist.Weve reliably measured black holes of masses up to 1020 solar masses in X-ray binaries (binary systems in which a single neutron star or black hole accretes matter from a donor star). But this is the first proof weve found that stellar-mass black holes of 25 solar masses can form in nature.Binaries consisting of two black holes can form in nature.As well discuss shortly, there are two theorized mechanisms for the formation of these black-hole binaries. Until now, however, there was no guarantee that either of those mechanisms worked!These black-hole binaries can inspiral and merge within the age of the universe.The formation of a black-hole binary is no guarantee that it will merge on a reasonable timescale: if the binary forms with enough separation, it could take longer than the age of the universe to merge. This detection proves that black-hole binaries can form with small enough separation to merge on observable timescales.What can we learn from GW150914?Expected increase in sensitivity for LIGO/Virgo detectors is shown as a function of total system mass (x-axis) and surveyed volume (y-axis). The red star indicates the mass of GW150914. [Abbott et al. 2016]For starters, we can throw out the lower estimates we had on merger rates. This event provides a new inferred binary-black-hole merger rate for the low-redshift universe of 2400 Gpc-3 yr-1.Another interesting conclusion about this binary system is that it probably formed in a low-metallicity environment (~ 1/2 solar metallicity). We infer this based on our current understanding of massive-star winds (which drive mass loss) and their dependence on metallicity: had the environment been high-metallicity, it is unlikely that such large black holes would have been able to form.What can we learn from future gravitational-wave detections?One of the key questions wed like to answer is: how do binary black holes form? Two primary mechanisms have been proposed:A binary star system contains two stars that are each massive enough to individually collapse into a black hole. If the binary isnt disrupted during the two collapse events, this forms an isolated black-hole binary.Single black holes form in dense cluster environments and then because they are the most massive objects sink to the center of the cluster. There they form pairs through dynamical interactions.Now that were able to observe black-hole binaries through gravitational-wave detections, one way we could distinguish between the two formation mechanisms is from spin measurements. If we discover a clear preference for the misalignment of the two black holes spins, this would favor formation in clusters, where theres no reason for the original spins to be aligned.The current, single detection is not enough to provide constraints, but if we can compile a large enough sample of events, we can start to present a statistical case favoring one channel over the other.What does GW150914 mean for the future of gravitational-wave detection?The fact that Advanced LIGO detected an event even before the start of its first official observing run is certainly promising! The LIGO team estimates that the volume the detectors can probe will still increase by at least a factor of ~10 as the observing runs become more sensitive and of longer duration.Aerial view of the Virgo interferometer near Pisa, Italy. [Virgo Collaboration]In addition, LIGO is not alone in the gravitational-wave game. LIGOs counterpart in Europe, Virgo, is also undergoing design upgrades to increase its sensitivity. Within this year, Virgo should be able to take data simultaneously with LIGO, allowing for better localization of sources. And the launch of (e)LISA, ESAs planned space-based interferometer, will grant us access to a new frequency range, opening a further window to the gravitational-wave sky.The detection of GW150914 marks the dawn of a new field: observational gravitational-wave astronomy. This detection alone confirms much that was purely theory before now and given that instrument upgrades are still underway, the future of gravitational-wave detection looks incredibly promising.BonusThis awesome video (produced by SXS lensing) shows an actual simulation of the black-hole merger GW150914. Time is slowed by a factor of 100, compared to the actual merger. The two black holes of29 and 36 solar masses warp the space-time around them, causing the distorted view.CitationB.P. Abbott et al. 2016 ApJL 818 L22. doi:10.3847/2041-8205/818/2/L22
Galaxy Rotation and Rapid Supermassive Binary Coalescence

NASA Astrophysics Data System (ADS)

Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood

2015-09-01

Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolution in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.
GALAXY ROTATION AND RAPID SUPERMASSIVE BINARY COALESCENCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holley-Bockelmann, Kelly; Khan, Fazeel Mahmood, E-mail: k.holley@vanderbilt.edu

2015-09-10

Galaxy mergers usher the supermassive black hole (SMBH) in each galaxy to the center of the potential, where they form an SMBH binary. The binary orbit shrinks by ejecting stars via three-body scattering, but ample work has shown that in spherical galaxy models, the binary separation stalls after ejecting all the stars in its loss cone—this is the well-known final parsec problem. However, it has been shown that SMBH binaries in non-spherical galactic nuclei harden at a nearly constant rate until reaching the gravitational wave regime. Here we use a suite of direct N-body simulations to follow SMBH binary evolutionmore » in both corotating and counterrotating flattened galaxy models. For N > 500 K, we find that the evolution of the SMBH binary is convergent and is independent of the particle number. Rotation in general increases the hardening rate of SMBH binaries even more effectively than galaxy geometry alone. SMBH binary hardening rates are similar for co- and counterrotating galaxies. In the corotating case, the center of mass of the SMBH binary settles into an orbit that is in corotation resonance with the background rotating model, and the coalescence time is roughly a few 100 Myr faster than a non-rotating flattened model. We find that counterrotation drives SMBHs to coalesce on a nearly radial orbit promptly after forming a hard binary. We discuss the implications for gravitational wave astronomy, hypervelocity star production, and the effect on the structure of the host galaxy.« less
Searching Ultra-compact Pulsar Binaries with Abnormal Timing Behavior

NASA Astrophysics Data System (ADS)

Gong, B. P.; Li, Y. P.; Yuan, J. P.; Tian, J.; Zhang, Y. Y.; Li, D.; Jiang, B.; Li, X. D.; Wang, H. G.; Zou, Y. C.; Shao, L. J.

2018-03-01

Ultra-compact pulsar binaries are both ideal sources of gravitational radiation for gravitational wave detectors and laboratories for fundamental physics. However, the shortest orbital period of all radio pulsar binaries is currently 1.6 hr. The absence of pulsar binaries with a shorter orbital period is most likely due to technique limit. This paper points out that a tidal effect occurring on pulsar binaries with a short orbital period can perturb the orbital elements and result in a significant change in orbital modulation, which dramatically reduces the sensitivity of the acceleration searching that is widely used. Here a new search is proposed. The abnormal timing residual exhibited in a single pulse observation is simulated by a tidal effect occurring on an ultra-compact binary. The reproduction of the main features represented by the sharp peaks displayed in the abnormal timing behavior suggests that pulsars like PSR B0919+06 could be a candidate for an ultra-compact binary of an orbital period of ∼10 minutes and a companion star of a white dwarf star. The binary nature of such a candidate is further tested by (1) comparing the predicted long-term binary effect with decades of timing noise observed and (2) observing the optical counterpart of the expected companion star. Test (1) likely supports our model, while more observations are needed in test (2). Some interesting ultra-compact binaries could be found in the near future by applying such a new approach to other binary candidates.
Approaching the Post-Newtonian Regime with Numerical Relativity: A Compact-Object Binary Simulation Spanning 350 Gravitational-Wave Cycles

NASA Astrophysics Data System (ADS)

Szilágyi, Béla; Blackman, Jonathan; Buonanno, Alessandra; Taracchini, Andrea; Pfeiffer, Harald P.; Scheel, Mark A.; Chu, Tony; Kidder, Lawrence E.; Pan, Yi

2015-07-01

We present the first numerical-relativity simulation of a compact-object binary whose gravitational waveform is long enough to cover the entire frequency band of advanced gravitational-wave detectors, such as LIGO, Virgo, and KAGRA, for mass ratio 7 and total mass as low as 45.5 M⊙ . We find that effective-one-body models, either uncalibrated or calibrated against substantially shorter numerical-relativity waveforms at smaller mass ratios, reproduce our new waveform remarkably well, with a negligible loss in detection rate due to modeling error. In contrast, post-Newtonian inspiral waveforms and existing calibrated phenomenological inspiral-merger-ringdown waveforms display greater disagreement with our new simulation. The disagreement varies substantially depending on the specific post-Newtonian approximant used.
Numerical relativity reaching into post-Newtonian territory: a compact-object binary simulation spanning 350 gravitational-wave cycles

NASA Astrophysics Data System (ADS)

Scheel, Mark; Szilagyi, Bela; Blackman, Jonathan; Chu, Tony; Kidder, Lawrence; Pfeiffer, Harald; Buonanno, Alessandra; Pan, Yi; Taracchini, Andrea; SXS Collaboration

2015-04-01

We present the first numerical-relativity simulation of a compact-object binary whose gravitational waveform is long enough to cover the entire frequency band of advanced gravitational-wave detectors such as LIGO, Virgo and KAGRA, for mass ratio 7 and total mass as low as 45 . 5M⊙ . We find that effective-one-body models, either uncalibrated or calibrated against substantially shorter numerical-relativity waveforms at smaller mass ratios, reproduce our new waveform remarkably well, with a loss in detection rate due to modeling error smaller than 0 . 3 % . In contrast, post-Newtonian inspiral waveforms and existing phenomenological inspiral-merger-ringdown waveforms display much greater disagreement with our new simulation. The disagreement varies substantially depending on the specific post-Newtonian approximant used.
Approaching the Post-Newtonian Regime with Numerical Relativity: A Compact-Object Binary Simulation Spanning 350 Gravitational-Wave Cycles.

PubMed

Szilágyi, Béla; Blackman, Jonathan; Buonanno, Alessandra; Taracchini, Andrea; Pfeiffer, Harald P; Scheel, Mark A; Chu, Tony; Kidder, Lawrence E; Pan, Yi

2015-07-17

We present the first numerical-relativity simulation of a compact-object binary whose gravitational waveform is long enough to cover the entire frequency band of advanced gravitational-wave detectors, such as LIGO, Virgo, and KAGRA, for mass ratio 7 and total mass as low as 45.5M_{⊙}. We find that effective-one-body models, either uncalibrated or calibrated against substantially shorter numerical-relativity waveforms at smaller mass ratios, reproduce our new waveform remarkably well, with a negligible loss in detection rate due to modeling error. In contrast, post-Newtonian inspiral waveforms and existing calibrated phenomenological inspiral-merger-ringdown waveforms display greater disagreement with our new simulation. The disagreement varies substantially depending on the specific post-Newtonian approximant used.
Black Hole Accretion Discs on a Moving Mesh

NASA Astrophysics Data System (ADS)

Ryan, Geoffrey

2017-01-01

We present multi-dimensional numerical simulations of black hole accretion disks relevant for the production of electromagnetic counterparts to gravitational wave sources. We perform these simulations with a new general relativistic version of the moving-mesh magnetohydrodynamics code DISCO which we will present. This open-source code, GR-DISCO uses an orbiting and shearing mesh which moves with the dominant flow velocity, greatly improving the numerical accuracy of the thermodynamic variables in supersonic flows while also reducing numerical viscosity and greatly increasing computational efficiency by allowing for a larger time step. We have used GR-DISCO to study black hole accretion discs subject to gravitational torques from a binary companion, relevant for both current and future supermassive binary black hole searches and also as a possible electromagnetic precursor mechanism for LIGO events. Binary torques in these discs excite spiral shockwaves which effectively transport angular momentum in the disc and propagate through the innermost stable orbit, leading to stress corresponding to an alpha-viscosity of 10-2. We also present three-dimensional GRMHD simulations of neutrino dominated accretion flows (NDAFs) occurring after a binary neutron star merger in order to elucidate the conditions for electromagnetic transient production accompanying these gravitational waves sources expected to be detected by LIGO in the near future.
Properties of the Binary Black Hole Merger GW150914

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Carbon Baiardi, L.; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devine, C.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etienne, Z.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gaebel, S. M.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gatto, A.; Gaur, G.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Johnson-McDaniel, N. K.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, C.; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Logue, J.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C. O.; Lovelace, G.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pan, Y.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Röver, C.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stevenson, S. P.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van der Sluys, M. V.; van Heijningen, J. V.; Vañó-Viñuales, A.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; Boyle, M.; Brügamin, B.; Campanelli, M.; Clark, M.; Hamberger, D.; Kidder, L. E.; Kinsey, M.; Laguna, P.; Ossokine, S.; Scheel, M. A.; Szilagyi, B.; Teukolsky, S.; Zlochower, Y.; LIGO Scientific Collaboration; Virgo Collaboration

2016-06-01

On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a gravitational-wave transient (GW150914); we characterize the properties of the source and its parameters. The data around the time of the event were analyzed coherently across the LIGO network using a suite of accurate waveform models that describe gravitational waves from a compact binary system in general relativity. GW150914 was produced by a nearly equal mass binary black hole of masses 3 6-4+5M⊙ and 2 9-4+4M⊙ ; for each parameter we report the median value and the range of the 90% credible interval. The dimensionless spin magnitude of the more massive black hole is bound to be <0.7 (at 90% probability). The luminosity distance to the source is 41 0-180+160 Mpc , corresponding to a redshift 0.0 9-0.04+0.03 assuming standard cosmology. The source location is constrained to an annulus section of 610 deg2 , primarily in the southern hemisphere. The binary merges into a black hole of mass 6 2-4+4M⊙ and spin 0.6 7-0.07+0.05. This black hole is significantly more massive than any other inferred from electromagnetic observations in the stellar-mass regime.
Effects of data quality vetoes on a search for compact binary coalescences in Advanced LIGO’s first observing run

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Bejger, M.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D’Antonio, S.; Danzmann, K.; Darman, N. S.; Dasgupta, A.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fenyvesi, E.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. 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S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chi-Woong; Kim, Chunglee; Kim, J.; Kim, K.; Kim, N.; Kim, W.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Lewis, J. B.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Nedkova, K.; Nelemans, G.; Nelson, T. J. N.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O’Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O’Reilly, B.; O’Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. 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C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yu, H.; Yvert, M.; Zadrożny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2018-03-01

The first observing run of Advanced LIGO spanned 4 months, from 12 September 2015 to 19 January 2016, during which gravitational waves were directly detected from two binary black hole systems, namely GW150914 and GW151226. Confident detection of gravitational waves requires an understanding of instrumental transients and artifacts that can reduce the sensitivity of a search. Studies of the quality of the detector data yield insights into the cause of instrumental artifacts and data quality vetoes specific to a search are produced to mitigate the effects of problematic data. In this paper, the systematic removal of noisy data from analysis time is shown to improve the sensitivity of searches for compact binary coalescences. The output of the PyCBC pipeline, which is a python-based code package used to search for gravitational wave signals from compact binary coalescences, is used as a metric for improvement. GW150914 was a loud enough signal that removing noisy data did not improve its significance. However, the removal of data with excess noise decreased the false alarm rate of GW151226 by more than two orders of magnitude, from 1 in 770 yr to less than 1 in 186 000 yr.
Properties of the Binary Black Hole Merger GW150914

NASA Technical Reports Server (NTRS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Camp, J. B.

2016-01-01

On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a gravitational-wave transient (GW150914); we characterize the properties of the source and its parameters. The data around the time of the event were analyzed coherently across the LIGO network using a suite of accurate waveform models that describe gravitational waves from a compact binary system in general relativity. GW150914 was produced by a nearly equal mass binary black hole of masses 36(+5/-4) solar mass and 29(+4/-4) solar mass; for each parameter we report the median value and the range of the 90% credible interval. The dimensionless spin magnitude of the more massive black hole is bound to be less than 0.7 (at 90% probability). The luminosity distance to the source is 410(+160/-180) Mpc, corresponding to a redshift 0.09(+0.03/-0.04) assuming standard cosmology. The source location is constrained to an annulus section of 610 sq deg, primarily in the southern hemisphere. The binary merges into a black hole of mass 62(+4/-4) solar mass and spin 0.67(+0.05/-0.07). This black hole is significantly more massive than any other inferred from electromagnetic observations in the stellar-mass regime.
Properties of the Binary Black Hole Merger GW150914.

PubMed

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Laguna, P; Ossokine, S; Scheel, M A; Szilagyi, B; Teukolsky, S; Zlochower, Y

2016-06-17

On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a gravitational-wave transient (GW150914); we characterize the properties of the source and its parameters. The data around the time of the event were analyzed coherently across the LIGO network using a suite of accurate waveform models that describe gravitational waves from a compact binary system in general relativity. GW150914 was produced by a nearly equal mass binary black hole of masses 36_{-4}^{+5}M_{⊙} and 29_{-4}^{+4}M_{⊙}; for each parameter we report the median value and the range of the 90% credible interval. The dimensionless spin magnitude of the more massive black hole is bound to be <0.7 (at 90% probability). The luminosity distance to the source is 410_{-180}^{+160} Mpc, corresponding to a redshift 0.09_{-0.04}^{+0.03} assuming standard cosmology. The source location is constrained to an annulus section of 610 deg^{2}, primarily in the southern hemisphere. The binary merges into a black hole of mass 62_{-4}^{+4}M_{⊙} and spin 0.67_{-0.07}^{+0.05}. This black hole is significantly more massive than any other inferred from electromagnetic observations in the stellar-mass regime.
Electromagnetic chirp of a compact binary black hole: A phase template for the gravitational wave inspiral

NASA Astrophysics Data System (ADS)

Haiman, Zoltán

2017-07-01

The gravitational waves (GWs) from a binary black hole (BBH) with masses 104≲M ≲107 M⊙ can be detected with the Laser Interferometer Space Antenna (LISA) once their orbital frequency exceeds 10-4- 10-5 Hz . The binary separation at this stage is a =O (100 )Rg (gravitational radius), and the orbital speed is v /c =O (0.1 ). We argue that at this stage, the binary will be producing bright electromagnetic (EM) radiation via gas bound to the individual BHs. Both BHs will have their own photospheres in x-ray and possibly also in optical bands. Relativistic Doppler modulations and lensing effects will inevitably imprint periodic variability in the EM light curve, tracking the phase of the orbital motion, and serving as a template for the GW inspiral waveform. Advanced localization of the source by LISA weeks to months prior to merger will enable a measurement of this EM chirp by wide-field x-ray or optical instruments. A comparison of the phases of the GW and EM chirp signals will help break degeneracies between system parameters, and probe a fractional difference Δ v in the propagation speed of photons and gravitons as low as Δ v /c ≈10-17.
ALGORITHMS AND PROGRAMS FOR STRONG GRAVITATIONAL LENSING IN KERR SPACE-TIME INCLUDING POLARIZATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Bin; Maddumage, Prasad; Kantowski, Ronald

2015-05-15

Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravitymore » field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python.« less

Algorithms and Programs for Strong Gravitational Lensing In Kerr Space-time Including Polarization

NASA Astrophysics Data System (ADS)

Chen, Bin; Kantowski, Ronald; Dai, Xinyu; Baron, Eddie; Maddumage, Prasad

2015-05-01

Active galactic nuclei (AGNs) and quasars are important astrophysical objects to understand. Recently, microlensing observations have constrained the size of the quasar X-ray emission region to be of the order of 10 gravitational radii of the central supermassive black hole. For distances within a few gravitational radii, light paths are strongly bent by the strong gravity field of the central black hole. If the central black hole has nonzero angular momentum (spin), then a photon’s polarization plane will be rotated by the gravitational Faraday effect. The observed X-ray flux and polarization will then be influenced significantly by the strong gravity field near the source. Consequently, linear gravitational lensing theory is inadequate for such extreme circumstances. We present simple algorithms computing the strong lensing effects of Kerr black holes, including the effects on polarization. Our algorithms are realized in a program “KERTAP” in two versions: MATLAB and Python. The key ingredients of KERTAP are a graphic user interface, a backward ray-tracing algorithm, a polarization propagator dealing with gravitational Faraday rotation, and algorithms computing observables such as flux magnification and polarization angles. Our algorithms can be easily realized in other programming languages such as FORTRAN, C, and C++. The MATLAB version of KERTAP is parallelized using the MATLAB Parallel Computing Toolbox and the Distributed Computing Server. The Python code was sped up using Cython and supports full implementation of MPI using the “mpi4py” package. As an example, we investigate the inclination angle dependence of the observed polarization and the strong lensing magnification of AGN X-ray emission. We conclude that it is possible to perform complex numerical-relativity related computations using interpreted languages such as MATLAB and Python.
Prospects for gravitational wave astronomy with next generation large-scale pulsar timing arrays

NASA Astrophysics Data System (ADS)

Wang, Yan; Mohanty, Soumya D.

2018-02-01

Next generation radio telescopes, namely the Five-hundred-meter Aperture Spherical Telescope (FAST) and the Square Kilometer Array (SKA), will revolutionize the pulsar timing arrays (PTAs) based gravitational wave (GW) searches. We review some of the characteristics of FAST and SKA, and the resulting PTAs, that are pertinent to the detection of gravitational wave signals from individual supermassive black hole binaries.
Results from a MHz gravitational wave search using the Fermilab Holometer

NASA Astrophysics Data System (ADS)

Kamai, Brittany; Holometer Collaboration Collaboration

2017-01-01

The Fermilab Holometer, two nested 40 meter Michelson interferometers, has extended the accessible gravitational wave frequency range from kHz to a broad range of MHz frequencies. I will present results from a 130-hr campaign that measured the energy density of gravitational waves in the MHz band. Additionally, this dataset was used to place constraints on the abundance of primordial black hole binaries.
Exploring the sensitivity of next generation gravitational wave detectors

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Ackley, K.; Adams, C.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Allen, B.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arun, K. G.; Ashton, G.; Ast, M.; Aston, S. M.; Aufmuth, P.; Aulbert, C.; Babak, S.; Baker, P. T.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barr, B.; Barsotti, L.; Bartlett, J.; Bartos, I.; Bassiri, R.; Batch, J. C.; Baune, C.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Biwer, C.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bock, O.; Bogan, C.; Bohe, A.; Bond, C.; Bork, R.; Bose, S.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Brinkmann, M.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Buonanno, A.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Caride, S.; Caudill, S.; Cavaglià, M.; Cepeda, C. B.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, C.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Collette, C. G.; Cominsky, L.; Constancio, M., Jr.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Dal Canton, T.; Danilishin, S. L.; Danzmann, K.; Darman, N. S.; Dasgupta, A.; Da Silva Costa, C. F.; Dave, I.; Davies, G. S.; Daw, E. J.; De, S.; DeBra, D.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Díaz, M. C.; Di Palma, I.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fenyvesi, E.; Ferreira, E. C.; Fisher, R. P.; Fletcher, M.; Frei, Z.; Freise, A.; Frey, R.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gaonkar, S. G.; Gaur, G.; Gehrels, N.; Geng, P.; George, J.; Gergely, L.; Ghosh, Abhirup; Ghosh, Archisman; Giaime, J. A.; Giardina, K. D.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Graef, C.; Graff, P. B.; Grant, A.; Gras, S.; Gray, C.; Green, A. C.; Grote, H.; Grunewald, S.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heintze, M. C.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isi, M.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jang, H.; Jani, K.; Jawahar, S.; Jian, L.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalili, F. Y.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chi-Woong; Kim, Chunglee; Kim, J.; Kim, K.; Kim, N.; Kim, W.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kozak, D. B.; Kringel, V.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leong, J. R.; Levin, Y.; Lewis, J. B.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lormand, M.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martin, I. W.; Martynov, D. V.; Mason, K.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Meshkov, S.; Messenger, C.; Messick, C.; Meyers, P. M.; Miao, H.; Middleton, H.; Mikhailov, E. E.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Mohapatra, S. R. P.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nayak, R. K.; Nedkova, K.; Nelson, T. J. N.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nitz, A.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Perri, L. M.; Phelps, M.; Pierro, V.; Pinto, I. M.; Pitkin, M.; Poe, M.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prokhorov, L.; Puncken, O.; Pürrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rakhmanov, M.; Raymond, V.; Read, J.; Reed, C. M.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Rollins, J. G.; Roma, V. J.; Romanov, G.; Romie, J. H.; Rowan, S.; Rüdiger, A.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O. E. S.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sergeev, A.; Shaddock, D. A.; Shaffer, T.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Szczepańczyk, M. J.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tomlinson, C.; Tornasi, Z.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Traylor, G.; Trifirò, D.; Tse, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vander-Hyde, D. C.; van Veggel, A. A.; Vass, S.; Vaulin, R.; Vecchio, A.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Vinciguerra, S.; Vine, D. J.; Vitale, S.; Vo, T.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Weaver, B.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yu, H.; Zanolin, M.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; (LIGO Scientific Collaboration; Harms, J.

2017-02-01

The second-generation of gravitational-wave detectors are just starting operation, and have already yielding their first detections. Research is now concentrated on how to maximize the scientific potential of gravitational-wave astronomy. To support this effort, we present here design targets for a new generation of detectors, which will be capable of observing compact binary sources with high signal-to-noise ratio throughout the Universe.
DISTINGUISHING COMPACT BINARY POPULATION SYNTHESIS MODELS USING GRAVITATIONAL WAVE OBSERVATIONS OF COALESCING BINARY BLACK HOLES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stevenson, Simon; Ohme, Frank; Fairhurst, Stephen, E-mail: simon.stevenson@ligo.org

2015-09-01

The coalescence of compact binaries containing neutron stars or black holes is one of the most promising signals for advanced ground-based laser interferometer gravitational-wave (GW) detectors, with the first direct detections expected over the next few years. The rate of binary coalescences and the distribution of component masses is highly uncertain, and population synthesis models predict a wide range of plausible values. Poorly constrained parameters in population synthesis models correspond to poorly understood astrophysics at various stages in the evolution of massive binary stars, the progenitors of binary neutron star and binary black hole systems. These include effects such asmore » supernova kick velocities, parameters governing the energetics of common envelope evolution and the strength of stellar winds. Observing multiple binary black hole systems through GWs will allow us to infer details of the astrophysical mechanisms that lead to their formation. Here we simulate GW observations from a series of population synthesis models including the effects of known selection biases, measurement errors and cosmology. We compare the predictions arising from different models and show that we will be able to distinguish between them with observations (or the lack of them) from the early runs of the advanced LIGO and Virgo detectors. This will allow us to narrow down the large parameter space for binary evolution models.« less
Evolutionary Pathways for Asteroid Satellites

NASA Astrophysics Data System (ADS)

Jacobson, Seth Andrew

2015-08-01

The YORP-induced rotational fission hypothesis is a proposed mechanism for the creation of small asteroid binaries, which make up approximately 1/6-th of the near-Earth asteroid and small Main Belt asteroid populations. The YORP effect is a radiative torque that rotationally accelerates asteroids on timescales of thousands to millions of years. As asteroids rotationally accelerate, centrifugal accelerations on material within the body can match gravitational accelerations holding that material in place. When this occurs, that material goes into orbit. Once in orbit that material coalesces into a companion that undergoes continued dynamical evolution.Observations with radar, photometric and direct imaging techniques reveal a diverse array of small asteroid satellites. These systems can be sorted into a number of morphologies according to size, multiplicity of members, dynamical orbit and spin states, and member shapes. For instance, singly synchronous binaries have short separation distances between the two members, rapidly rotating oblate primary members, and tidally locked prolate secondary members. Other confirmed binary morphologies include doubly synchronous, tight asynchronous and wide asynchronous binaries. Related to these binary morphologies are unbound paired asteroid systems and bi-lobate contact binaries.A critical test for the YORP-induced rotational fission hypothesis is whether the binary asteroids produced evolve to the observed binary and related systems. In this talk I will review how this evolution is believed to occur according to gravitational dynamics, mutual body tides and the binary YORP effect.
TIGER: A data analysis pipeline for testing the strong-field dynamics of general relativity with gravitational wave signals from coalescing compact binaries

NASA Astrophysics Data System (ADS)

Agathos, M.; Del Pozzo, W.; Li, T. G. F.; Van Den Broeck, C.; Veitch, J.; Vitale, S.

2014-04-01

The direct detection of gravitational waves with upcoming second-generation gravitational wave observatories such as Advanced LIGO and Advanced Virgo will allow us to probe the genuinely strong-field dynamics of general relativity (GR) for the first time. We have developed a data analysis pipeline called TIGER (test infrastructure for general relativity), which uses signals from compact binary coalescences to perform a model-independent test of GR. In this paper we focus on signals from coalescing binary neutron stars, for which sufficiently accurate waveform models are already available which can be generated fast enough on a computer that they can be used in Bayesian inference. By performing numerical experiments in stationary, Gaussian noise, we show that for such systems, TIGER is robust against a number of unmodeled fundamental, astrophysical, and instrumental effects, such as differences between waveform approximants, a limited number of post-Newtonian phase contributions being known, the effects of neutron star tidal deformability on the orbital motion, neutron star spins, and instrumental calibration errors.
On the Unreasonable Effectiveness of post-Newtonian Theory in Gravitational-Wave Physics

ScienceCinema

Will, Clifford M.

2017-12-22

The first indirect detection of gravitational waves involved a binary system of neutron stars.Â In the future, the first direct detection may also involve binary systems -- inspiralling and merging binary neutron stars or black holes. This means that it is essential to understand in full detail the two-body system in general relativity, a notoriously difficult problem with a long history. Post-Newtonian approximation methods are thought to work only under slow motion and weak field conditions, while numerical solutions of Einstein's equations are thought to be limited to the final merger phase.Â Recent results have shown that post-Newtonian approximations seem to remain unreasonably valid well into the relativistic regime, while advances in numerical relativity now permit solutions for numerous orbits before merger.Â It is now possible to envision linking post-Newtonian theory and numerical relativity to obtain a complete "solution" of the general relativistic two-body problem.Â These solutions will play a central role in detecting and understanding gravitational wave signals received by interferometric observatories on Earth and in space.
Gravitational Waves from Black Hole Mergers

NASA Technical Reports Server (NTRS)

Centrella, Joan

2007-01-01

The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, data analysis, and astrophysics.
Gravitational-wave cosmography with LISA and the Hubble tension

NASA Astrophysics Data System (ADS)

Kyutoku, Koutarou; Seto, Naoki

2017-04-01

We propose that stellar-mass binary black holes like GW150914 will become a tool to explore the local Universe within ˜100 Mpc in the era of the Laser Interferometer Space Antenna (LISA). High calibration accuracy and annual motion of LISA could enable us to localize up to ≈60 binaries more accurately than the error volume of ≈100 Mpc3 without electromagnetic counterparts under moderately optimistic assumptions. This accuracy will give us a fair chance to determine the host object solely by gravitational waves. By combining the luminosity distance extracted from gravitational waves with the cosmological redshift determined from the host, the local value of the Hubble parameter will be determined up to a few % without relying on the empirically constructed distance ladder. Gravitational-wave cosmography would pave the way for resolution of the disputed Hubble tension, where the local and global measurements disagree in the value of the Hubble parameter at 3.4 σ level, which amounts to ≈9 %.
LISA Mission Concept Study, Laser Interferometer Space Antenna for the Detection and Observation of Gravitational Waves

NASA Technical Reports Server (NTRS)

Folkner, W. M.; Bender, P. L.; Stebbins, R. T.

1998-01-01

This document presents the results of a design feasibility study for LISA (Laser Interferometer Space Antenna). The goal of LISA is to detect and study low-frequency astrophysical gravitational radiation from strongly relativistic regions. Astrophysical sources potentially visible to LISA include extra-galactic massive black hole binaries at cosmological distances, binary systems composed of a compact star and a massive black hole, galactic neutron star-black hole binaries, and background radiation from the Big Bang. The LISA mission will comprise three spacecraft located five million kilometers apart forming an equilateral triangle in an Earth-trailing orbit. Fluctuations in separation between shielded test masses located within each spacecraft will be determined by optical interferometry which determines the phase shift of laser light transmitted between the test masses.
High energy radiation precursors to the collapse of black holes binaries based on resonating plasma modes

NASA Astrophysics Data System (ADS)

Coppi, B.

2018-05-01

The presence of well organized plasma structures around binary systems of collapsed objects [1,2] (black holes and neutron stars) is proposed in which processes can develop [3] leading to high energy electromagnetic radiation emission immediately before the binary collapse. The formulated theoretical model supporting this argument shows that resonating plasma collective modes can be excited in the relevant magnetized plasma structure. Accordingly, the collapse of the binary approaches, with the loss of angular momentum by emission of gravitational waves [2], the resonance conditions with vertically standing plasma density and magnetic field oscillations are met. Then, secondary plasma modes propagating along the magnetic field are envisioned to be sustained with mode-particle interactions producing the particle populations responsible for the observable electromagnetic radiation emission. Weak evidence for a precursor to the binary collapse reported in Ref. [2], has been offered by the Agile X-γ-ray observatory [4] while the August 17 (2017) event, identified first by the LIGO-Virgo detection of gravitational waves and featuring the inferred collapse of a neutron star binary, improves the evidence of such a precursor. A new set of experimental observations is needed to reassess the presented theory.
Effects of Disk Warping on the Inclination Evolution of Star-Disk-Binary Systems

NASA Astrophysics Data System (ADS)

Zanazzi, J. J.; Lai, Dong

2018-04-01

Several recent studies have suggested that circumstellar disks in young stellar binaries may be driven into misalignement with their host stars due to secular gravitational interactions between the star, disk and the binary companion. The disk in such systems is twisted/warped due to the gravitational torques from the oblate central star and the external companion. We calculate the disk warp profile, taking into account of bending wave propagation and viscosity in the disk. We show that for typical protostellar disk parameters, the disk warp is small, thereby justifying the "flat-disk" approximation adopted in previous theoretical studies. However, the viscous dissipation associated with the small disk warp/twist tends to drive the disk toward alignment with the binary or the central star. We calculate the relevant timescales for the alignment. We find the alignment is effective for sufficiently cold disks with strong external torques, especially for systems with rapidly rotating stars, but is ineffective for the majority of star-disk-binary systems. Viscous warp driven alignment may be necessary to account for the observed spin-orbit alignment in multi-planet systems if these systems are accompanied by an inclined binary companion.
Effects of disc warping on the inclination evolution of star-disc-binary systems

NASA Astrophysics Data System (ADS)

Zanazzi, J. J.; Lai, Dong

2018-07-01

Several recent studies have suggested that circumstellar discs in young stellar binaries may be driven into misalignement with their host stars due to the secular gravitational interactions between the star, disc, and the binary companion. The disc in such systems is twisted/warped due to the gravitational torques from the oblate central star and the external companion. We calculate the disc warp profile, taking into account the bending wave propagation and viscosity in the disc. We show that for typical protostellar disc parameters, the disc warp is small, thereby justifying the `flat-disc' approximation adopted in previous theoretical studies. However, the viscous dissipation associated with the small disc warp/twist tends to drive the disc towards alignment with the binary or the central star. We calculate the relevant time-scales for the alignment. We find that the alignment is effective for sufficiently cold discs with strong external torques, especially for systems with rapidly rotating stars, but is ineffective for the majority of the star-disc-binary systems. Viscous warp-driven alignment may be necessary to account for the observed spin-orbit alignment in multiplanet systems if these systems are accompanied by an inclined binary companion.
Resonant dynamics of gravitationally bound pair of binaries: the case of 1:1 resonance

NASA Astrophysics Data System (ADS)

Breiter, Slawomir; Vokrouhlický, David

2018-04-01

The work presents a study of the 1:1 resonance case in a hierarchical quadruple stellar system of the 2+2 type. The resonance appears if orbital periods of both binaries are approximately equal. It is assumed that both periods are significantly shorter than the period of principal orbit of one binary with respect to the other. In these circumstances, the problem can be treated as three independent Kepler problems perturbed by mutual gravitational interactions. By means of canonical perturbation methods, the planar problem is reduced to a secular system with 1 degree of freedom involving a resonance angle (the difference of mean longitudes of the binaries) and its conjugate momentum (involving the ratio of orbital period in one binary to the period of principal orbit). The resonant model is supplemented with short periodic perturbations expressions, and verified by the comparison with numerical integration of the original equations of motion. Estimates of the binaries periods variations indicate that the effect is rather weak, but possibly detectible if it occurs in a moderately compact system. However, the analysis of resonance capture scenarios implies that the 1:1 resonance should be exceptional amongst the 2+2 quadruples.
General relativistic dynamics of an extreme mass-ratio binary interacting with an external body

NASA Astrophysics Data System (ADS)

Yang, Huan; Casals, Marc

2017-10-01

We study the dynamics of a hierarchical three-body system in the general relativistic regime: an extreme mass-ratio inner binary under the tidal influence of an external body. The inner binary consists of a central Schwarzschild black hole and a test body moving around it. We discuss three types of tidal effects on the orbit of the test body. First, the angular momentum of the inner binary precesses around the angular momentum of the outer binary. Second, the tidal field drives a "transient resonance" when the radial and azimuthal frequencies are commensurable. In contrast with resonances driven by the gravitational self-force, this tidal-driven resonance may boost the orbital angular momentum and eccentricity (a relativistic version of the Kozai-Lidov effect). Finally, for an orbit-dynamical effect during the nonresonant phase, we calculate the correction to the innermost stable circular (mean) orbit due to the tidal interaction. Hierarchical three-body systems are potential sources for future space-based gravitational wave missions, and the tidal effects that we find could contribute significantly to their waveform.
Georgia tech catalog of gravitational waveforms

NASA Astrophysics Data System (ADS)

Jani, Karan; Healy, James; Clark, James A.; London, Lionel; Laguna, Pablo; Shoemaker, Deirdre

2016-10-01

This paper introduces a catalog of gravitational waveforms from the bank of simulations by the numerical relativity effort at Georgia Tech. Currently, the catalog consists of 452 distinct waveforms from more than 600 binary black hole simulations: 128 of the waveforms are from binaries with black hole spins aligned with the orbital angular momentum, and 324 are from precessing binary black hole systems. The waveforms from binaries with non-spinning black holes have mass-ratios q = m 1/m 2 ≤ 15, and those with precessing, spinning black holes have q ≤ 8. The waveforms expand a moderate number of orbits in the late inspiral, the burst during coalescence, and the ring-down of the final black hole. Examples of waveforms in the catalog matched against the widely used approximate models are presented. In addition, predictions of the mass and spin of the final black hole by phenomenological fits are tested against the results from the simulation bank. The role of the catalog in interpreting the GW150914 event and future massive binary black-hole search in LIGO is discussed. The Georgia Tech catalog is publicly available at einstein.gatech.edu/catalog.
Electromagnetic signature of supermassive black hole binaries that enter their gravitational-wave induced inspiral

DOE Office of Scientific and Technical Information (OSTI.GOV)

Loeb, Abraham

2010-02-15

Mergers of gas-rich galaxies lead to black hole binaries that coalesce as a result of dynamical friction on the ambient gas. Once the binary tightens to < or approx. 10{sup 3} Schwarzschild radii, its merger is driven by the emission of gravitational waves (GWs). We show that this transition occurs generically at orbital periods of {approx}1-10 years and an orbital velocity v of a few thousand km s{sup -1}, with a very weak dependence on the supply rate of gas (v{proportional_to}M{sup 1/8}). Therefore, as binaries enter their GW-dominated inspiral, they inevitably induce large periodic shifts in the broad emission linesmore » of any associated quasar(s). The probability of finding a binary in tighter configurations scales as v{sup -8} owing to their much shorter lifetimes. Narrow-band monitoring of the broad emission lines of quasars on time scales of months to decades can set a lower limit on the expected rate of GW sources for the Laser Interferometer Space Antenna.« less
DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Xian; Amaro-Seoane, Pau, E-mail: xian.chen@pku.edu.cn, E-mail: pau@ice.cat

The formation of compact stellar-mass binaries is a difficult, but interesting problem in astrophysics. There are two main formation channels: in the field via binary star evolution, or in dense stellar systems via dynamical interactions. The Laser Interferometer Gravitational-wave Observatory (LIGO) has detected black hole binaries (BHBs) via their gravitational radiation. These detections provide us with information about the physical parameters of the system. It has been claimed that when the Laser Interferometer Space Antenna (LISA) is operating, the joint observation of these binaries with LIGO will allow us to derive the channels that lead to their formation. However, wemore » show that for BHBs in dense stellar systems dynamical interactions could lead to high eccentricities such that a fraction of the relativistic mergers are not audible to LISA. A non-detection by LISA puts a lower limit of about 0.005 on the eccentricity of a BHB entering the LIGO band. On the other hand, a deci-Hertz observatory, like DECIGO or Tian Qin, would significantly enhance the chances of a joint detection and shed light on the formation channels of these binaries.« less
An Anzatz about Gravity, Cosmology, and the Pioneer Anomaly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murad, Paul

2010-01-28

The Pulsar 1913+16 binary system may represent a 'young' binary system where previously it is claimed that the dynamics are due to either a third body or a gravitational vortex. Usually a binary system's trajectory could reside in a single ellipse or circular orbit; the double ellipse implies that the 1913+16 system may be starting to degenerate into a single elliptical trajectory. This could be validated only after a considerably long time period. In a majority of binary star systems, the weights of both stars are claimed by analysis to be the same. It may be feasible that the trajectorymore » of the primary spinning star could demonstrate repulsive gravitational effects where the neutron star's high spin rate induces a repulsive gravitational source term that compensates for inertia. If true, then it provides evidence that angular momentum may be translated into linear momentum as a repulsive source that has propulsion implications. This also suggests mass differences may dictate the neutron star's spin rate as an artifact of a natural gravitational process. Moreover, the reduced matter required by the 'dark' mass hypothesis may not exist but these effects could be due to repulsive gravity residing in rotating celestial bodies.The Pioneer anomaly observed on five different deep-space spacecraft, is the appearance of a constant gravitational force directed toward the sun. Pioneer spacecraft data reveals that a vortex-like magnetic field exists emanating from the sun. The spiral arms of the Sun's magnetic vortex field may be causal to this constant acceleration. This may profoundly provide a possible experimental verification on a cosmic scale of Gertsenshtein's principle relating gravity to electromagnetism. Furthermore, the anomalous acceleration may disappear once the spacecraft passes out into a magnetic spiral furrow, which is something that needs to be observed in the future. Other effects offer an explanation from space-time geometry to the Yarkovsky thermal effects are discussed.« less

Gravitational waves from neutron star excitations in a binary inspiral

NASA Astrophysics Data System (ADS)

Parisi, Alessandro; Sturani, Riccardo

2018-02-01

In the context of a binary inspiral of mixed neutron star-black hole systems, we investigate the excitation of the neutron star oscillation modes by the orbital motion. We study generic eccentric orbits and show that tidal interaction can excite the f -mode oscillations of the star by computing the amount of energy and angular momentum deposited into the star by the orbital motion tidal forces via closed form analytic expressions. We study the f -mode oscillations of cold neutron stars using recent microscopic nuclear equations of state, and we compute their imprint into the emitted gravitational waves.
Application of graphics processing units to search pipelines for gravitational waves from coalescing binaries of compact objects

NASA Astrophysics Data System (ADS)

Chung, Shin Kee; Wen, Linqing; Blair, David; Cannon, Kipp; Datta, Amitava

2010-07-01

We report a novel application of a graphics processing unit (GPU) for the purpose of accelerating the search pipelines for gravitational waves from coalescing binaries of compact objects. A speed-up of 16-fold in total has been achieved with an NVIDIA GeForce 8800 Ultra GPU card compared with one core of a 2.5 GHz Intel Q9300 central processing unit (CPU). We show that substantial improvements are possible and discuss the reduction in CPU count required for the detection of inspiral sources afforded by the use of GPUs.
The Binary Pulsar: Gravity Waves Exist.

ERIC Educational Resources Information Center

Will, Clifford

1987-01-01

Reviews the history of pulsars generally and the 1974 discovery of the binary pulsar by Joe Taylor and Russell Hulse specifically. Details the data collection and analysis used by Taylor and Hulse. Uses this discussion as support for Albert Einstein's theory of gravitational waves. (CW)
Local constraints on cosmic string loops from photometry and pulsar timing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pshirkov, M. S.; Tuntsov, A. V.; Sternberg Astronomical Institute, M.V. Lomonosov Moscow State University, 119992

2010-04-15

We constrain the cosmological density of cosmic string loops using two observational signatures--gravitational microlensing and the Kaiser-Stebbins effect. Photometry from RXTE and CoRoT space missions and pulsar timing from Parkes Pulsar Timing Array, Arecibo and Green Bank radio telescopes allow us to probe cosmic strings in a wide range of tensions G{mu}/c{sup 2}=10{sup -16} divide 10{sup -10}. We find that pulsar timing data provide the most stringent constraints on the abundance of light strings at the level {Omega}{sub s{approx}}10{sup -3}. Future observational facilities such as the Square Kilometer Array will allow one to improve these constraints by orders of magnitude.
Search for dark matter effects on gravitational signals from neutron star mergers

NASA Astrophysics Data System (ADS)

Ellis, John; Hektor, Andi; Hütsi, Gert; Kannike, Kristjan; Marzola, Luca; Raidal, Martti; Vaskonen, Ville

2018-06-01

Motivated by the recent detection of the gravitational wave signal emitted by a binary neutron star merger, we analyse the possible impact of dark matter on such signals. We show that dark matter cores in merging neutron stars may yield an observable supplementary peak in the gravitational wave power spectral density following the merger, which could be distinguished from the features produced by the neutron components.
HUBBLE UNCOVERS MYSTERY OBJECTS IN THE DENSE CORE OF A NEARBY STAR CLUSTER

NASA Technical Reports Server (NTRS)

2002-01-01

Piercing the heart of a glittering swarm of stars, NASA's sharp-eyed Hubble Space Telescope unveils the central region of the globular cluster M22, a 12- to 14-billion-year-old grouping of stars in the constellation Sagittarius. The telescope's view of the cluster's core measures 3.3 light-years across. The stars near the cluster's core are 100,000 times more numerous than those in the Sun's neighborhood. Buried in the glow of starlight are about six 'mystery objects,' which astronomers estimate are no larger than one quarter the mass of the giant planet Jupiter, the solar system's heftiest planet. The mystery objects are too far and dim for Hubble to see directly. Instead, the orbiting observatory detected these unseen celestial bodies by looking for their gravitational effects on the light from far distant stars. In this case, the stars are far beyond the cluster in the galactic bulge, about 30,000 light-years from Earth at the center of the Milky Way Galaxy. M22 is 8,500 light-years away. The invisible objects betrayed their presence by bending the starlight gravitationally and amplifying it, a phenomenon known as microlensing. From February 22 to June 15, 1999, Hubble's Wide Field and Planetary Camera 2 looked through this central region and monitored 83,000 stars. During that time the orbiting observatory recorded six unexpectedly brief microlensing events. In each case a background star jumped in brightness for less than 20 hours before dropping back to normal. These transitory spikes in brightness mean that the object passing in front of the star must have been much smaller than a normal star. Hubble also detected one clear microlensing event. In that observation a star appeared about 10 times brighter over an 18-day span before returning to normal. Astronomers traced the leap in brightness to a dwarf star in the cluster floating in front of the background star. The inset photo shows the entire globular cluster of about 10 million stars. M22 is about 60 light-years wide. The image was taken in June 1995 by the Burrell Schmidt telescope at the Case Western Reserve University's Warner and Swasey Observatory on Kitt Peak in Arizona. This release is issued jointly by NASA and ESA. Credits for Hubble image: NASA, Kailash Sahu, Stefano Casertano, Mario Livio, Ron Gilliland (Space Telescope Science Institute), Nino Panagia (European Space Agency/Space Telescope Science Institute), Michael Albrow and Mike Potter (Space Telescope Science Institute) Credits for ground-based image: Nigel A.Sharp, REU program/AURA/NOAO/NSF
Liquid Tunable Microlenses based on MEMS techniques

PubMed Central

Zeng, Xuefeng; Jiang, Hongrui

2013-01-01

The recent rapid development in microlens technology has provided many opportunities for miniaturized optical systems, and has found a wide range of applications. Of these microlenses, tunable-focus microlenses are of special interest as their focal lengths can be tuned using micro-scale actuators integrated with the lens structure. Realization of such tunable microlens generally relies on the microelectromechanical system (MEMS) technologies. Here, we review the recent progress in tunable liquid microlenses. The underlying physics relevant to these microlenses are first discussed, followed by description of three main categories of tunable microlenses involving MEMS techniques, mechanically driven, electrically driven, and those integrated within microfluidic systems. PMID:24163480
Binary-disk interaction. II. Gap-opening criteria for unequal-mass binaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Del Valle, Luciano; Escala, Andrés, E-mail: ldelvalleb@gmail.com

We study the interaction of an unequal-mass binary with an isothermal circumbinary disk, motivated by the theoretical and observational evidence that after a major merger of gas-rich galaxies, a massive gaseous disk with a supermassive black hole binary will be formed in the nuclear region. We focus on the gravitational torques that the binary exerts on the disk and how these torques can drive the formation of a gap in the disk. This exchange of angular momentum between the binary and the disk is mainly driven by the gravitational interaction between the binary and a strong nonaxisymmetric density perturbation thatmore » is produced in the disk, in response to the presence of the binary. Using smoothed particle hydrodynamics numerical simulations, we test two gap-opening criteria, one that assumes the geometry of the density perturbation is an ellipsoid/thick spiral and another that assumes a flat spiral geometry for the density perturbation. We find that the flat spiral gap-opening criterion successfully predicts which simulations will have a gap in the disk and which will not. We also study the limiting cases predicted by the gap-opening criteria. Since the viscosity in our simulations is considerably smaller than the expected value in the nuclear regions of gas-rich merging galaxies, we conclude that in such environments the formation of a circumbinary gap is unlikely.« less
Lamb shift and the gravitational binding energy for binary black holes

NASA Astrophysics Data System (ADS)

Porto, Rafael A.

2017-07-01

We show that the correction to the gravitational binding energy for binary black holes due to the tail effect resembles the Lamb shift in the Hydrogen atom. In both cases a conservative effect arises from interactions with radiation modes, and moreover an explicit cancelation between near and far zone divergences is at work. In addition, regularization scheme-dependence may introduce "ambiguity parameters." This is remediated—within an effective field theory approach—by the implementation of the zero-bin subtraction. We illustrate the procedure explicitly for the Lamb shift, by performing an ambiguity-free derivation within the framework of nonrelativistic electrodynamics. We also derive the renormalization group equations from which we reproduce Bethe logarithm (at order αe5log αe), and likewise the contribution to the gravitational potential from the tail effect (proportional to v8log v ).
Asteroid Properties from Photometric Observations: Constraining Non-Gravitational Processes in Asteroids

NASA Astrophysics Data System (ADS)

Pravec, P.

2013-05-01

From October 2012 we run our NEOSource project on the Danish 1.54-m telescope on La Silla. The primary aim of the project is to study non-gravitational processes in asteroids near the Earth and in their source regions in the main asteroidal belt. In my talk, I will give a brief overview of our current knowledge of the asteroidal non- gravitational processes and how we study them with photometric observations. I will talk especially about binary and paired asteroids that appear to be formed by rotational fission, about detecting the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) and BYORP (binary YORP) effects of anisotropic thermal emission from asteroids that change their spins and satellite orbits, and about non-principal axis rotators (the so called "tumblers") among the smallest, super-critically rotating asteroids with sizes < 100 meters.
Binary Systems as Test-Beds of Gravity Theories

NASA Astrophysics Data System (ADS)

Damour, Thibault

The discovery of binary pulsars in 1974 [1] opened up a new testing ground for relativistic gravity. Before this discovery, the only available testing ground for relativistic gravity was the solar system. As Einstein's theory of General Relativity (GR) is one of the basic pillars of modern science, it deserves to be tested, with the highest possible accuracy, in all its aspects. In the solar sys tem, the gravitational field is slowly varying and represents only a very small deformation of a flat spacetime. As a consequence, solar system tests can only probe the quasi-stationary (non-radiative) weak-field limit of relativis tic gravity. By contrast binary systems containing compact objects (neutron stars or black holes) involve spacetime domains (inside and near the compact objects) where the gravitational field is strong. Indeed, the surface relativistic gravitational field h 00 ≈ 2 GM/c 2 R of a neutron star is of order 0.4, which is close to the one of a black hole (2GM/c 2 R = 1) and much larger than the surface gravitational fields of solar system bodies: (2GM/c 2 R)Sun ˜ 10-6, (2GM/c 2 R)Earth ˜ 10-9. In addition, the high stability of “pulsar clocks” has made it possible to monitor the dynamics of its orbital motion down to a precision allowing one to measure the small (˜ (v/c)5) orbital effects linked to the propagation of the gravitational field at the velocity of light between the pulsar and its companion.
A SEARCH FOR STELLAR-MASS BLACK HOLES VIA ASTROMETRIC MICROLENSING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, J. R.; Sinukoff, E.; Ofek, E. O.

While dozens of stellar-mass black holes (BHs) have been discovered in binary systems, isolated BHs have eluded detection. Their presence can be inferred when they lens light from a background star. We attempt to detect the astrometric lensing signatures of three photometrically identified microlensing events, OGLE-2011-BLG-0022, OGLE-2011-BLG-0125, and OGLE-2012-BLG-0169 (OB110022, OB110125, and OB120169), located toward the Galactic Bulge. These events were selected because of their long durations, which statistically favors more massive lenses. Astrometric measurements were made over one to two years using laser-guided adaptive optics observations from the W. M. Keck Observatory. Lens model parameters were first constrained bymore » the photometric light curves. The OB120169 light curve is well fit by a single-lens model, while both OB110022 and OB110125 light curves favor binary lens models. Using the photometric fits as prior information, no significant astrometric lensing signal was detected and all targets were consistent with linear motion. The significant lack of astrometric signal constrains the lens mass of OB110022 to 0.05–1.79 M {sub ⊙} in a 99.7% confidence interval, which disfavors a BH lens. Fits to OB110125 yielded a reduced Einstein crossing time and insufficient observations during the peak, so no mass limits were obtained. Two degenerate solutions exist for OB120169, which have a lens mass between 0.2–38.8 M {sub ⊙} and 0.4–39.8 M {sub ⊙} for a 99.7% confidence interval. Follow-up observations of OB120169 will further constrain the lens mass. Based on our experience, we use simulations to design optimal astrometric observing strategies and show that with more typical observing conditions the detection of BHs is feasible.« less
PALFA Discovers Neutron Stars on a Collision Course

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2018-03-01

Got any plans in 46 million years? If not, you should keep an eye out for PSR J1946+2052 around that time this upcoming merger of two neutron stars promises to be an exciting show!Survey SuccessAverage profile for PSR J1946+2052 at 1.43 GHz from a 2 hr observation from the Arecibo Observatory. [Stovall et al. 2018]It seems like we just wrote about the dearth of known double-neutron-star systems, and about how new surveys are doing their best to find more of these compact binaries. Observing these systems improves our knowledge of how pairs of evolved stars behave before they eventually spiral in, merge, and emit gravitational waves that detectors like the Laser Interferometer Gravitational-wave Observatory might observe.Todays study, led by Kevin Stovall (National Radio Astronomy Observatory), goes to show that these surveys are doing a great job so far! Yet another double-neutron-star binary, PSR J1946+2052, has now been discovered as part of the Arecibo L-Band Feed Array pulsar (PALFA) survey. This one is especially unique due to the incredible speed with which these neutron stars orbit each other and their correspondingly (relatively!) short timescale for merger.An Extreme ExampleThe PALFA survey, conducted with the enormous 305-meter radio dish at Arecibo, has thus far resulted in the discovery of 180 pulsars including two double-neutron-star systems. The most recent discovery by Stovall and collaborators brings that number up to three, for a grand total of 16 binary-neutron-star systems (confirmed and unconfirmed) known to date.The 305-m Arecibo Radio Telescope, built into the landscape at Arecibo, Puerto Rico. [NOAO/AURA/NSF/H. Schweiker/WIYN]The newest binary in this collection, PSR J1946+2052, exhibits a pulsar with a 17-millisecond spin period thatwhips around its compact companion at a terrifying rate: the binary period is just 1.88 hours. Follow-up observations with the Jansky Very Large Array and other telescopes allowed the team to identify the binarys location to high precision and establish additional parameters of the system.PSR J1946+2052 is a system of extremes. The binarys total mass is found to be 2.5 solar masses, placing it among the lightest binary-neutron-star systems known. Its orbital period is the shortest weve observed, and the two neutron stars are on track to merge in less time than any other known neutron-star binaries: in just 46 million years. When the two stars reach the final stages of their merger, the effects of the pulsars rapid spin on the gravitational-wave signal will be the largest of any such system discovered to date.More Tests of General RelativityWhat can PSR J1946+2052 do for us? This extreme system will be especially useful as a gravitational laboratory. Continued observations of PSR J1946+2052 will pin down with unprecedented precision parameters like the Einstein delay and the rate of decay of the binarys orbit due to the emission of gravitational waves, testing the predictions of general relativity to an order of magnitude higher precision than was possible before.As we expect there to be thousands of systems like PSR J1946+2052 in our galaxy alone, better understanding this binary and finding more like it continue to be important steps toward interpreting compact-object merger observations in the future.CitationK. Stovall et al 2018 ApJL 854 L22. doi:10.3847/2041-8213/aaad06
CRITICAL CURVES AND CAUSTICS OF TRIPLE-LENS MODELS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daněk, Kamil; Heyrovský, David, E-mail: kamil.danek@utf.mff.cuni.cz, E-mail: heyrovsky@utf.mff.cuni.cz

2015-06-10

Among the 25 planetary systems detected up to now by gravitational microlensing, there are two cases of a star with two planets, and two cases of a binary star with a planet. Other, yet undetected types of triple lenses include triple stars or stars with a planet with a moon. The analysis and interpretation of such events is hindered by the lack of understanding of essential characteristics of triple lenses, such as their critical curves and caustics. We present here analytical and numerical methods for mapping the critical-curve topology and caustic cusp number in the parameter space of n-point-mass lenses.more » We apply the methods to the analysis of four symmetric triple-lens models, and obtain altogether 9 different critical-curve topologies and 32 caustic structures. While these results include various generic types, they represent just a subset of all possible triple-lens critical curves and caustics. Using the analyzed models, we demonstrate interesting features of triple lenses that do not occur in two-point-mass lenses. We show an example of a lens that cannot be described by the Chang–Refsdal model in the wide limit. In the close limit we demonstrate unusual structures of primary and secondary caustic loops, and explain the conditions for their occurrence. In the planetary limit we find that the presence of a planet may lead to a whole sequence of additional caustic metamorphoses. We show that a pair of planets may change the structure of the primary caustic even when placed far from their resonant position at the Einstein radius.« less
Measuring the Binary Black Hole Mass Spectrum with an Astrophysically Motivated Parameterization

NASA Astrophysics Data System (ADS)

Talbot, Colm; Thrane, Eric

2018-04-01

Gravitational-wave detections have revealed a previously unknown population of stellar mass black holes with masses above 20 M ⊙. These observations provide a new way to test models of stellar evolution for massive stars. By considering the astrophysical processes likely to determine the shape of the binary black hole mass spectrum, we construct a parameterized model to capture key spectral features that relate gravitational-wave data to theoretical stellar astrophysics. In particular, we model the signature of pulsational pair-instability supernovae, which are expected to cause all stars with initial mass 100 M ⊙ ≲ M ≲ 150 M ⊙ to form ∼40 M ⊙ black holes. This would cause a cutoff in the black hole mass spectrum along with an excess of black holes near 40 M ⊙. We carry out a simulated data study to illustrate some of the stellar physics that can be inferred using gravitational-wave measurements of binary black holes and demonstrate several such inferences that might be made in the near future. First, we measure the minimum and maximum stellar black hole mass. Second, we infer the presence of a peak due to pair-instability supernovae. Third, we measure the distribution of black hole mass ratios. Finally, we show how inadequate models of the black hole mass spectrum lead to biased estimates of the merger rate and the amplitude of the stochastic gravitational-wave background.
Search for Gravitational Waves Associated with γ-ray Bursts Detected by the Interplanetary Network

NASA Astrophysics Data System (ADS)

Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Agathos, M.; Aggarwal, N.; Aguiar, O. D.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Andersen, M.; Anderson, R. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J. S.; Ast, S.; Aston, S. M.; Astone, P.; Aufmuth, P.; Augustus, H.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P. T.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauchrowitz, J.; Bauer, Th. S.; Baune, C.; Bavigadda, V.; Behnke, B.; Bejger, M.; Beker, M. G.; Belczynski, C.; Bell, A. S.; Bell, C.; Bergmann, G.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; Bosi, L.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brückner, F.; Buchman, S.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burman, R.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Calderón Bustillo, J.; Calloni, E.; Camp, J. B.; Campsie, P.; Cannon, K. C.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Carbone, L.; Caride, S.; Castaldi, G.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Celerier, C.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, X.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S. S. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, D. E.; Clark, J. A.; Clayton, J. H.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C.; Colombini, M.; Cominsky, L.; Constancio, M.; Conte, A.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Croce, R. P.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Cutler, C.; Dahl, K.; Dal Canton, T.; Damjanic, M.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; Dayanga, T.; DeBra, D.; Debreczeni, G.; Degallaix, J.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Dickson, J.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Dolique, V.; Dominguez, E.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Endrőczi, G.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fazi, D.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Feroz, F.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grover, K.; Grunewald, S.; Guidi, G. M.; Guido, C. J.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Ha, J.; Hall, E. D.; Hamilton, W.; Hammer, D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Holt, K.; Hopkins, P.; Horrom, T.; Hoske, D.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hu, Y.; Huerta, E.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Idrisy, A.; Ingram, D. R.; Inta, R.; Islas, G.; Isogai, T.; Ivanov, A.; Iyer, B. R.; Izumi, K.; Jacobson, M.; Jang, H.; Jaranowski, P.; Ji, Y.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karlen, J.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Keiser, G. M.; Keitel, D.; Kelley, D. B.; Kells, W.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, C.; Kim, K.; Kim, N. G.; Kim, N.; Kim, S.; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kline, J.; Koehlenbeck, S.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, A.; Kumar, D. Nanda; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Lam, P. K.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, J.; Lee, P. J.; Leonardi, M.; Leong, J. R.; Leonor, I.; Le Roux, A.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B.; Lewis, J.; Li, T. G. F.; Libbrecht, K.; Libson, A.; Lin, A. C.; Littenberg, T. B.; Lockerbie, N. A.; Lockett, V.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lopez, E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Lubinski, M. J.; Lück, H.; Lundgren, A. P.; Ma, Y.; Macdonald, E. P.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R.; Mageswaran, M.; Maglione, C.; Mailand, K.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Manca, G. M.; Mandel, I.; Mandic, V.; Mangano, V.; Mangini, N. M.; Mansell, G.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Martinelli, L.; Martynov, D.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Matichard, F.; Matone, L.; Mavalvala, N.; May, G.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McLin, K.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Meinders, M.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Mikhailov, E. E.; Milano, L.; Miller, J.; Minenkov, Y.; Mingarelli, C. M. F.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nagy, M. F.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nelemans, G.; Neri, I.; Neri, M.; Newton, G.; Nguyen, T.; Nielsen, A. B.; Nissanke, S.; Nitz, A. H.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Ochsner, E.; O'Dell, J.; Oelker, E.; Oh, J. J.; Oh, S. H.; Ohme, F.; Omar, S.; Oppermann, P.; Oram, R.; O'Reilly, B.; Ortega, W.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Palashov, O.; Palomba, C.; Pan, H.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Paris, H.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Pedraza, M.; Pele, A.; Penn, S.; Perreca, A.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J.; Poggiani, R.; Poteomkin, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qin, J.; Quetschke, V.; Quintero, E.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Raja, S.; Rajalakshmi, G.; Rakhmanov, M.; Ramet, C.; Ramirez, K.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Recchia, S.; Reed, C. M.; Regimbau, T.; Reid, S.; Reitze, D. H.; Reula, O.; Rhoades, E.; Ricci, F.; Riesen, R.; Riles, K.; Robertson, N. A.; Robinet, F.; Rocchi, A.; Roddy, S. B.; Rolland, L.; Rollins, J. G.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J. R.; Sankar, S.; Sannibale, V.; Santiago-Prieto, I.; Saracco, E.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R.; Scheuer, J.; Schilling, R.; Schilman, M.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D. A.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siellez, K.; Siemens, X.; Sigg, D.; Simakov, D.; Singer, A.; Singer, L.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Son, E. J.; Sorazu, B.; Souradeep, T.; Staley, A.; Stebbins, J.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Stephens, B. C.; Steplewski, S.; Stevenson, S.; Stone, R.; Stops, D.; Strain, K. A.; Straniero, N.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tao, J.; Tarabrin, S. P.; Taylor, R.; Tellez, G.; Thirugnanasambandam, M. P.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Travasso, F.; Traylor, G.; Tse, M.; Tshilumba, D.; Tuennermann, H.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Sluys, M. V.; van Heijningen, J.; van Veggel, A. A.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vousden, W. D.; Vyachanin, S. P.; Wade, A. R.; Wade, L.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, M.; Wang, X.; Ward, R. L.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Williams, K.; Williams, L.; Williams, R.; Williams, T. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Wolovick, N.; Worden, J.; Wu, Y.; Yablon, J.; Yakushin, I.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yoshida, S.; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, Fan; Zhang, L.; Zhao, C.; Zhu, H.; Zhu, X. J.; Zucker, M. E.; Zuraw, S.; Zweizig, J.; Aptekar, R. L.; Atteia, J. L.; Cline, T.; Connaughton, V.; Frederiks, D. D.; Golenetskii, S. V.; Hurley, K.; Krimm, H. A.; Marisaldi, M.; Pal'shin, V. D.; Palmer, D.; Svinkin, D. S.; Terada, Y.; von Kienlin, A.; LIGO Scientific Collaboration; Virgo Collaboration; IPN Collaboration

2014-07-01

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10-2M⊙c2 at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.
Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by the Interplanetary Network

NASA Technical Reports Server (NTRS)

Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Acernese, F.; Blackbum, L.; Camp, J. B.; Gehrels, N.; Graff, P. B.;

2014-01-01

We present the results of a search for gravitational waves associated with 223 gamma ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(exp-2) solar mass c(exp 2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.

Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network.

PubMed

Aasi, J; Abbott, B P; Abbott, R; Abbott, T; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Affeldt, C; Agathos, M; Aggarwal, N; Aguiar, O D; Ajith, P; Alemic, A; Allen, B; Allocca, A; Amariutei, D; Andersen, M; Anderson, R A; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C; Areeda, J S; Ast, S; Aston, S M; Astone, P; Aufmuth, P; Augustus, H; Aulbert, C; Aylott, B E; Babak, S; Baker, P T; Ballardin, G; Ballmer, S W; Barayoga, J C; Barbet, M; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barton, M A; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Bauchrowitz, J; Bauer, Th S; Baune, C; Bavigadda, V; Behnke, B; Bejger, M; Beker, M G; Belczynski, C; Bell, A S; Bell, C; Bergmann, G; Bersanetti, D; Bertolini, A; Betzwieser, J; Bilenko, I A; Billingsley, G; Birch, J; Biscans, S; Bitossi, M; Biwer, C; Bizouard, M A; Black, E; Blackburn, J K; Blackburn, L; Blair, D; Bloemen, S; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; 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Mansell, G; Mantovani, M; Marchesoni, F; Marion, F; Márka, S; Márka, Z; Markosyan, A; Maros, E; Marque, J; Martelli, F; Martin, I W; Martin, R M; Martinelli, L; Martynov, D; Marx, J N; Mason, K; Masserot, A; Massinger, T J; Matichard, F; Matone, L; Mavalvala, N; May, G; Mazumder, N; Mazzolo, G; McCarthy, R; McClelland, D E; McGuire, S C; McIntyre, G; McIver, J; McLin, K; Meacher, D; Meadors, G D; Mehmet, M; Meidam, J; Meinders, M; Melatos, A; Mendell, G; Mercer, R A; Meshkov, S; Messenger, C; Meyer, M S; Meyers, P M; Mezzani, F; Miao, H; Michel, C; Mikhailov, E E; Milano, L; Miller, J; Minenkov, Y; Mingarelli, C M F; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moe, B; Moggi, A; Mohan, M; Mohapatra, S R P; Moraru, D; Moreno, G; Morgado, N; Morriss, S R; Mossavi, K; Mours, B; Mow-Lowry, C M; Mueller, C L; Mueller, G; Mukherjee, S; Mullavey, A; Munch, J; Murphy, D; Murray, P G; Mytidis, A; Nagy, M F; Nardecchia, I; Naticchioni, L; Nayak, R K; Necula, V; Nelemans, G; Neri, I; Neri, M; Newton, G; Nguyen, T; Nielsen, A B; Nissanke, S; Nitz, A H; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Ochsner, E; O'Dell, J; Oelker, E; Oh, J J; Oh, S H; Ohme, F; Omar, S; Oppermann, P; Oram, R; O'Reilly, B; Ortega, W; O'Shaughnessy, R; Osthelder, C; Ottaway, D J; Ottens, R S; Overmier, H; Owen, B J; Padilla, C; Pai, A; Palashov, O; Palomba, C; Pan, H; Pan, Y; Pankow, C; Paoletti, F; Papa, M A; Paris, H; Pasqualetti, A; Passaquieti, R; Passuello, D; Pedraza, M; Pele, A; Penn, S; Perreca, A; Phelps, M; Pichot, M; Pickenpack, M; Piergiovanni, F; Pierro, V; Pinard, L; Pinto, I M; Pitkin, M; Poeld, J; Poggiani, R; Poteomkin, A; Powell, J; Prasad, J; Predoi, V; Premachandra, S; Prestegard, T; Price, L R; Prijatelj, M; Privitera, S; Prodi, G A; Prokhorov, L; Puncken, O; Punturo, M; Puppo, P; Pürrer, M; Qin, J; Quetschke, V; Quintero, E; Quitzow-James, R; Raab, F J; Rabeling, D S; Rácz, I; Radkins, H; Raffai, P; Raja, S; Rajalakshmi, G; Rakhmanov, M; Ramet, C; Ramirez, K; 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Vousden, W D; Vyachanin, S P; Wade, A R; Wade, L; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, M; Wang, X; Ward, R L; Was, M; Weaver, B; Wei, L-W; Weinert, M; Weinstein, A J; Weiss, R; Welborn, T; Wen, L; Wessels, P; West, M; Westphal, T; Wette, K; Whelan, J T; White, D J; Whiting, B F; Wiesner, K; Wilkinson, C; Williams, K; Williams, L; Williams, R; Williams, T D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M; Winkler, W; Wipf, C C; Wiseman, A G; Wittel, H; Woan, G; Wolovick, N; Worden, J; Wu, Y; Yablon, J; Yakushin, I; Yam, W; Yamamoto, H; Yancey, C C; Yang, H; Yoshida, S; Yvert, M; Zadrożny, A; Zanolin, M; Zendri, J-P; Zhang, Fan; Zhang, L; Zhao, C; Zhu, H; Zhu, X J; Zucker, M E; Zuraw, S; Zweizig, J; Aptekar, R L; Atteia, J L; Cline, T; Connaughton, V; Frederiks, D D; Golenetskii, S V; Hurley, K; Krimm, H A; Marisaldi, M; Pal'shin, V D; Palmer, D; Svinkin, D S; Terada, Y; von Kienlin, A

2014-07-04

We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.
Gravitational Wave Astronomy:The High Frequency Window

NASA Astrophysics Data System (ADS)

Andersson, Nils; Kokkotas, Kostas D.

As several large scale interferometers are beginning to take data at sensitivities where astrophysical sources are predicted, the direct detection of gravitational waves may well be imminent. This would (finally) open the long anticipated gravitational-wave window to our Universe, and should lead to a much improved understanding of the most violent processes imaginable; the formation of black holes and neutron stars following core collapse supernovae and the merger of compact objects at the end of binary inspiral. Over the next decade we can hope to learn much about the extreme physics associated with, in particular, neutron stars. This contribution is divided in two parts. The first part provides a text-book level introduction to gravitational radiation. The key concepts required for a discussion of gravitational-wave physics are introduced. In particular, the quadrupole formula is applied to the anticipated bread-and-butter source for detectors like LIGO, GEO600, EGO and TAMA300: inspiralling compact binaries. The second part provides a brief review of high frequency gravitational waves. In the frequency range above (say) 100 Hz, gravitational collapse, rotational instabilities and oscillations of the remnant compact objects are potentially important sources of gravitational waves. Significant and unique information concerning the various stages of collapse, the evolution of protoneutron stars and the details of the supranuclear equation of state of such objects can be drawn from careful study of the gravitational-wave signal. As the amount of exciting physics one may be able to study via the detections of gravitational waves from these sources is truly inspiring, there is strong motivation for the development of future generations of ground based detectors sensitive in the range from hundreds of Hz to several kHz.
Simulations of nearly extremal binary black holes

NASA Astrophysics Data System (ADS)

Giesler, Matthew; Scheel, Mark; Hemberger, Daniel; Lovelace, Geoffrey; Kuper, Kevin; Boyle, Michael; Szilagyi, Bela; Kidder, Lawrence; SXS Collaboration

2015-04-01

Astrophysical black holes could have nearly extremal spins; therefore, nearly extremal black holes could be among the binaries that current and future gravitational-wave observatories will detect. Predicting the gravitational waves emitted by merging black holes requires numerical-relativity simulations, but these simulations are especially challenging when one or both holes have mass m and spin S exceeding the Bowen-York limit of S /m2 = 0 . 93 . Using improved methods we simulate an unequal-mass, precessing binary black hole coalescence, where the larger black hole has S /m2 = 0 . 99 . We also use these methods to simulate a nearly extremal non-precessing binary black hole coalescence, where both black holes have S /m2 = 0 . 994 , nearly reaching the Novikov-Thorne upper bound for holes spun up by thin accretion disks. We demonstrate numerical convergence and estimate the numerical errors of the waveforms; we compare numerical waveforms from our simulations with post-Newtonian and effective-one-body waveforms; and we compare the evolution of the black-hole masses and spins with analytic predictions.

Accurate inspiral-merger-ringdown gravitational waveforms for nonspinning black-hole binaries including the effect of subdominant modes

NASA Astrophysics Data System (ADS)

Mehta, Ajit Kumar; Mishra, Chandra Kant; Varma, Vijay; Ajith, Parameswaran

2017-12-01

We present an analytical waveform family describing gravitational waves (GWs) from the inspiral, merger, and ringdown of nonspinning black-hole binaries including the effect of several nonquadrupole modes [(ℓ=2 ,m =±1 ),(ℓ=3 ,m =±3 ),(ℓ=4 ,m =±4 ) apart from (ℓ=2 ,m =±2 )]. We first construct spin-weighted spherical harmonics modes of hybrid waveforms by matching numerical-relativity simulations (with mass ratio 1-10) describing the late inspiral, merger, and ringdown of the binary with post-Newtonian/effective-one-body waveforms describing the early inspiral. An analytical waveform family is constructed in frequency domain by modeling the Fourier transform of the hybrid waveforms making use of analytical functions inspired by perturbative calculations. The resulting highly accurate, ready-to-use waveforms are highly faithful (unfaithfulness ≃10-4- 10-2 ) for observation of GWs from nonspinning black-hole binaries and are extremely inexpensive to generate.
DOE Office of Scientific and Technical Information (OSTI.GOV)

Fischetti, Sebastian; Cadonati, Laura; Mohapatra, Satyanarayan R. P.

Recent years have witnessed tremendous progress in numerical relativity and an ever improving performance of ground-based interferometric gravitational wave detectors. In preparation for the Advanced Laser Interferometer Gravitational Wave Observatory (Advanced LIGO) and a new era in gravitational wave astronomy, the numerical relativity and gravitational wave data analysis communities are collaborating to ascertain the most useful role for numerical relativity waveforms in the detection and characterization of binary black hole coalescences. In this paper, we explore the detectability of equal mass, merging black hole binaries with precessing spins and total mass M{sub T}(set-membership sign)[80,350]M{sub {center_dot}}, using numerical relativity waveforms andmore » templateless search algorithms designed for gravitational wave bursts. In particular, we present a systematic study using waveforms produced by the MayaKranc code that are added to colored, Gaussian noise and analyzed with the Omega burst search algorithm. Detection efficiency is weighed against the orientation of one of the black-hole's spin axes. We find a strong correlation between the detection efficiency and the radiated energy and angular momentum, and that the inclusion of the l=2, m={+-}1, 0 modes, at a minimum, is necessary to account for the full dynamics of precessing systems.« less
Search for gravitational wave ringdowns from perturbed intermediate mass black holes in LIGO-Virgo data from 2005-2010

NASA Astrophysics Data System (ADS)

Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Agathos, M.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Andersen, M.; Anderson, R.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Austin, L.; Aylott, B. E.; Babak, S.; Baker, P. T.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauchrowitz, J.; Bauer, Th. S.; Bavigadda, V.; Behnke, B.; Bejger, M.; Beker, M. G.; Belczynski, C.; Bell, A. S.; Bell, C.; Benacquista, M.; Bergmann, G.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; Bosi, L.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brückner, F.; Buchman, S.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Burman, R.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Bustillo, J. Calderón; Calloni, E.; Camp, J. B.; Campsie, P.; Cannon, K. C.; Canuel, B.; Cao, J.; Capano, C. D.; Carbognani, F.; Carbone, L.; Caride, S.; Castiglia, A.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Celerier, C.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, X.; Chen, Y.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Chow, J.; Christensen, N.; Chu, Q.; Chua, S. S. Y.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C.; Colombini, M.; Cominsky, L.; Constancio, M.; Conte, A.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corpuz, A.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coughlin, S.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dahl, K.; Canton, T. Dal; Damjanic, M.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dattilo, V.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; Dayanga, T.; Debreczeni, G.; Degallaix, J.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Dolique, V.; Donath, A.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dossa, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Effler, A.; Eggenstein, H.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Endrőczi, G.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Feroz, F.; Ferrante, I.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gair, J.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, C.; Gleason, J.; Goetz, E.; Goetz, R.; Goggin, L. M.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grover, K.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Hammer, D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Hooper, S.; Hopkins, P.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hu, Y.; Huerta, E.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Iyer, B. R.; Izumi, K.; Jacobson, M.; James, E.; Jang, H.; Jaranowski, P.; Ji, Y.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karlen, J.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Keiser, G. M.; Keitel, D.; Kelley, D. B.; Kells, W.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, C.; Kim, K.; Kim, N.; Kim, N. G.; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kline, J.; Koehlenbeck, S.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kremin, A.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, A.; Kumar, D. Nanda; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Kwee, P.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J.; Leonardi, M.; Leong, J. R.; Le Roux, A.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B.; Lewis, J.; Li, T. G. F.; Libbrecht, K.; Libson, A.; Lin, A. C.; Littenberg, T. B.; Litvine, V.; Lockerbie, N. A.; Lockett, V.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Lubinski, M. J.; Lück, H.; Luijten, E.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macarthur, J.; Macdonald, E. P.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-Sandoval, F.; Mageswaran, M.; Maglione, C.; Mailand, K.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Manca, G. M.; Mandel, I.; Mandic, V.; Mangano, V.; Mangini, N.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Marque, J.; Martelli, F.; Martin, I. W.; Martin, R. M.; Martinelli, L.; Martynov, D.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McLin, K.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Meinders, M.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyers, P.; Miao, H.; Michel, C.; Mikhailov, E. E.; Milano, L.; Milde, S.; Miller, J.; Minenkov, Y.; Mingarelli, C. M. F.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Moesta, P.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Morgado, N.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nagy, M. F.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nelemans, G.; Neri, I.; Neri, M.; Newton, G.; Nguyen, T.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Ochsner, E.; O'Dell, J.; Oelker, E.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oppermann, P.; O'Reilly, B.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Palashov, O.; Palomba, C.; Pan, H.; Pan, Y.; Pankow, C.; Paoletti, F.; Papa, M. A.; Paris, H.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Pedraza, M.; Penn, S.; Perreca, A.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J.; Poggiani, R.; Poteomkin, A.; Powell, J.; Prasad, J.; Premachandra, S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Qin, J.; Quetschke, V.; Quintero, E.; Quiroga, G.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Raja, S.; Rajalakshmi, G.; Rakhmanov, M.; Ramet, C.; Ramirez, K.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Recchia, S.; Reed, C. M.; Regimbau, T.; Reid, S.; Reitze, D. H.; Rhoades, E.; Ricci, F.; Riles, K.; Robertson, N. A.; Robinet, F.; Rocchi, A.; Rodruck, M.; Rolland, L.; Rollins, J. G.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J. R.; Sannibale, V.; Santiago-Prieto, I.; Saracco, E.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R.; Scheuer, J.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siellez, K.; Siemens, X.; Sigg, D.; Simakov, D.; Singer, A.; Singer, L.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Son, E. J.; Sorazu, B.; Souradeep, T.; Staley, A.; Stebbins, J.; Steinlechner, J.; Steinlechner, S.; Stephens, B. C.; Steplewski, S.; Stevenson, S.; Stone, R.; Stops, D.; Strain, K. A.; Straniero, N.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, R.; Thirugnanasambandam, M. P.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Travasso, F.; Traylor, G.; Tse, M.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Urbanek, K.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; van der Sluys, M. V.; van Heijningen, J.; van Veggel, A. A.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Verma, S. S.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vousden, W. D.; Vyachanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Walker, M.; Wallace, L.; Wang, M.; Wang, X.; Ward, R. L.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Williams, K.; Williams, L.; Williams, R.; Williams, T.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yang, Z.; Yoshida, S.; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, Fan; Zhang, L.; Zhao, C.; Zhu, X. J.; Zucker, M. E.; Zuraw, S.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration

2014-05-01

We report results from a search for gravitational waves produced by perturbed intermediate mass black holes (IMBH) in data collected by LIGO and Virgo between 2005 and 2010. The search was sensitive to astrophysical sources that produced damped sinusoid gravitational wave signals, also known as ringdowns, with frequency 50≤f0/Hz≤2000 and decay timescale 0.0001≲τ/s≲0.1 characteristic of those produced in mergers of IMBH pairs. No significant gravitational wave candidate was detected. We report upper limits on the astrophysical coalescence rates of IMBHs with total binary mass 50≤M/M⊙≤450 and component mass ratios of either 1:1 or 4:1. For systems with total mass 100≤M/M⊙≤150, we report a 90% confidence upper limit on the rate of binary IMBH mergers with nonspinning and equal mass components of 6.9×10-8 Mpc-3 yr-1. We also report a rate upper limit for ringdown waveforms from perturbed IMBHs, radiating 1% of their mass as gravitational waves in the fundamental, ℓ=m =2, oscillation mode, that is nearly three orders of magnitude more stringent than previous results.
NANOGrav Constraints on Gravitational Wave Bursts with Memory

NASA Astrophysics Data System (ADS)

Arzoumanian, Z.; Brazier, A.; Burke-Spolaor, S.; Chamberlin, S. J.; Chatterjee, S.; Christy, B.; Cordes, J. M.; Cornish, N. J.; Demorest, P. B.; Deng, X.; Dolch, T.; Ellis, J. A.; Ferdman, R. D.; Fonseca, E.; Garver-Daniels, N.; Jenet, F.; Jones, G.; Kaspi, V. M.; Koop, M.; Lam, M. T.; Lazio, T. J. W.; Levin, L.; Lommen, A. N.; Lorimer, D. R.; Luo, J.; Lynch, R. S.; Madison, D. R.; McLaughlin, M. A.; McWilliams, S. T.; Nice, D. J.; Palliyaguru, N.; Pennucci, T. T.; Ransom, S. M.; Siemens, X.; Stairs, I. H.; Stinebring, D. R.; Stovall, K.; Swiggum, J.; Vallisneri, M.; van Haasteren, R.; Wang, Y.; Zhu, W. W.; NANOGrav Collaboration

2015-09-01

Among efforts to detect gravitational radiation, pulsar timing arrays are uniquely poised to detect “memory” signatures, permanent perturbations in spacetime from highly energetic astrophysical events such as mergers of supermassive black hole binaries. The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) observes dozens of the most stable millisecond pulsars using the Arecibo and Green Bank radio telescopes in an effort to study, among other things, gravitational wave memory. We herein present the results of a search for gravitational wave bursts with memory (BWMs) using the first five years of NANOGrav observations. We develop original methods for dramatically speeding up searches for BWM signals. In the directions of the sky where our sensitivity to BWMs is best, we would detect mergers of binaries with reduced masses of {10}9 {M}⊙ out to distances of 30 Mpc; such massive mergers in the Virgo cluster would be marginally detectable. We find no evidence for BWMs. However, with our non-detection, we set upper limits on the rate at which BWMs of various amplitudes could have occurred during the time spanned by our data—e.g., BWMs with amplitudes greater than 10-13 must encounter the Earth at a rate less than 1.5 yr-1.
Binary Black Holes, Numerical Relativity, and Gravitational Waves

NASA Technical Reports Server (NTRS)

Centrella, Joan

2007-01-01

The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these wave patterns. For more than 30 years, scientists have tried to compute these wave patterns. However, their computer codes have been plagued by problems that caused them to crash. This situation has changed dramatically in the past 2 years, with a series of amazing breakthroughs. This talk will take you on this quest for these gravitational wave patterns, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LISA
Cosmic Messengers: Binary Black Holes and Gravitational Waves

NASA Technical Reports Server (NTRS)

Centrella, Joan

2007-01-01

The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein s equations of general relativity on a computer in order to calculate these wave patterns. For more than 30 years, scientists have tried to compute these wave patterns. However, their computer codes have been plagued by problems that caused them to crash. . This situation has changed dramatically in the past 2 years, with a series of amazing breakthroughs. This talk will take you on this quest for these gravitational wave patterns, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will. be observed by LISA.
Binary Black Holes and Gravitational Waves

NASA Technical Reports Server (NTRS)

Centrella, Joan

2007-01-01

The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LIGO and LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these wave patterns.
Foundations of an effective-one-body model for coalescing binaries on eccentric orbits

NASA Astrophysics Data System (ADS)

Hinderer, Tanja; Babak, Stanislav

2017-11-01

We develop the foundations of an effective-one-body (EOB) model for eccentric binary coalescences that includes the conservative dynamics, radiation reaction, and gravitational waveform modes from the inspiral and the merger-ringdown signals. Our approach uses the strategy that is commonly employed in black-hole perturbation theory: we introduce an efficient, relativistic parameterization of the dynamics that is defined by the orbital geometry and consists of a set of phase variables and quantities that evolve only due to gravitational radiation reaction. Specializing to nonspinning binaries, we derive the EOB equations of motion for the new variables and make use of the fundamental frequencies of the motion to compute the binary's radiative multipole moments that determine the gravitational waves. Our treatment has several advantages over the quasi-Keplerian approach that is often used in post-Newtonian (PN) calculations: a smaller set of variables, parameters that reflect the features of strong-field dynamics, and a greater transparency of the calculations when using the fundamental frequencies that leads to simplifications and an unambiguous orbit-averaging operation. While our description of the conservative dynamics is fully relativistic, we limit explicit derivations in the radiative sector to 1.5PN order for simplicity. This already enables us to establish methods for computing both instantaneous and hereditary contributions to the gravitational radiation in EOB coordinates that have straightforward extensions to higher PN order. The weak-field, small eccentricity limit of our results for the orbit-averaged fluxes agrees with known PN results when expressed in terms of gauge-invariant quantities. We further address considerations for the numerical implementation of the model and the completion of the waveforms to include the merger and ringdown signals, and provide illustrative results.
Electromagnetic transients as triggers in searches for gravitational waves from compact binary mergers

NASA Astrophysics Data System (ADS)

Kelley, Luke Zoltan; Mandel, Ilya; Ramirez-Ruiz, Enrico

2013-06-01

The detection of an electromagnetic transient which may originate from a binary neutron star merger can increase the probability that a given segment of data from the LIGO-Virgo ground-based gravitational-wave detector network contains a signal from a binary coalescence. Additional information contained in the electromagnetic signal, such as the sky location or distance to the source, can help rule out false alarms and thus lower the necessary threshold for a detection. Here, we develop a framework for determining how much sensitivity is added to a gravitational-wave search by triggering on an electromagnetic transient. We apply this framework to a variety of relevant electromagnetic transients, from short gamma-ray bursts (GRBs) to signatures of r-process heating to optical and radio orphan afterglows. We compute the expected rates of multimessenger observations in the advanced detector era and find that searches triggered on short GRBs—with current high-energy instruments, such as Fermi—and nucleosynthetic “kilonovae”—with future optical surveys, like the Large Synoptic Survey Telescope—can boost the number of multimessenger detections by 15% and 40%, respectively, for a binary neutron star progenitor model. Short GRB triggers offer precise merger timing but suffer from detection rates decreased by beaming and the high a priori probability that the source is outside the LIGO-Virgo sensitive volume. Isotropic kilonovae, on the other hand, could be commonly observed within the LIGO-Virgo sensitive volume with an instrument roughly an order of magnitude more sensitive than current optical surveys. We propose that the most productive strategy for making multimessenger gravitational-wave observations is using triggers from future deep, optical all-sky surveys, with characteristics comparable to the Large Synoptic Survey Telescope, which could make as many as ten such coincident observations a year.
Binary asteroid population. 2. Anisotropic distribution of orbit poles of small, inner main-belt binaries

NASA Astrophysics Data System (ADS)

Pravec, P.; Scheirich, P.; Vokrouhlický, D.; Harris, A. W.; Kušnirák, P.; Hornoch, K.; Pray, D. P.; Higgins, D.; Galád, A.; Világi, J.; Gajdoš, Š.; Kornoš, L.; Oey, J.; Husárik, M.; Cooney, W. R.; Gross, J.; Terrell, D.; Durkee, R.; Pollock, J.; Reichart, D. E.; Ivarsen, K.; Haislip, J.; LaCluyze, A.; Krugly, Yu. N.; Gaftonyuk, N.; Stephens, R. D.; Dyvig, R.; Reddy, V.; Chiorny, V.; Vaduvescu, O.; Longa-Peña, P.; Tudorica, A.; Warner, B. D.; Masi, G.; Brinsfield, J.; Gonçalves, R.; Brown, P.; Krzeminski, Z.; Gerashchenko, O.; Shevchenko, V.; Molotov, I.; Marchis, F.

2012-03-01

Our photometric observations of 18 main-belt binary systems in more than one apparition revealed a strikingly high number of 15 having positively re-observed mutual events in the return apparitions. Our simulations of the survey showed that it cannot be due to an observational selection effect and that the data strongly suggest that poles of mutual orbits between components of binary asteroids in the primary size range 3-8 km are not distributed randomly: The null hypothesis of an isotropic distribution of the orbit poles is rejected at a confidence level greater than 99.99%. Binary orbit poles concentrate at high ecliptic latitudes, within 30° of the poles of the ecliptic. We propose that the binary orbit poles oriented preferentially up/down-right are due to either of the two processes: (i) the YORP tilt of spin axes of their parent bodies toward the asymptotic states near obliquities 0° and 180° (pre-formation mechanism) or (ii) the YORP tilt of spin axes of the primary components of already formed binary systems toward the asymptotic states near obliquities 0° and 180° (post-formation mechanism). The alternative process of elimination of binaries with poles closer to the ecliptic by dynamical instability, such as the Kozai effect due to gravitational perturbations from the Sun, does not explain the observed orbit pole concentration. This is because for close binary asteroid systems, the gravitational effects of primary’s irregular shape dominate the solar-tide effect.
Hangup effect in unequal mass binary black hole mergers and further studies of their gravitational radiation and remnant properties

NASA Astrophysics Data System (ADS)

Healy, James; Lousto, Carlos O.

2018-04-01

We present the results of 74 new simulations of nonprecessing spinning black hole binaries with mass ratios q =m1/m2 in the range 1 /7 ≤q ≤1 and individual spins covering the parameter space -0.95 ≤α1 ,2≤0.95 . We supplement those runs with 107 previous simulations to study the hangup effect in black hole mergers, i.e. the delay or prompt merger of spinning holes with respect to nonspinning binaries. We perform the numerical evolution for typically the last ten orbits before the merger and down to the formation of the final remnant black hole. This allows us to study the hangup effect for unequal mass binaries leading us to identify the spin variable that controls the number of orbits before merger as S→ hu.L ^ , where S→ hu=(1 +1/2 m/2 m1 )S→ 1+(1 +1/2 m/1 m2 )S→ 2 . We also combine the total results of those 181 simulations to obtain improved fitting formulas for the remnant final black hole mass, spin and recoil velocity as well as for the peak luminosity and peak frequency of the gravitational strain, and find new correlations among them. This accurate new set of simulations enhances the number of available numerical relativity waveforms available for parameter estimation of gravitational wave observations.
Implications of PSR J0737-3039B for the Galactic NS-NS binary merger rate

NASA Astrophysics Data System (ADS)

Kim, Chunglee; Perera, Benetge Bhakthi Pranama; McLaughlin, Maura A.

2015-03-01

The Double Pulsar (PSR J0737-3039) is the only neutron star-neutron star (NS-NS) binary in which both NSs have been detectable as radio pulsars. The Double Pulsar has been assumed to dominate the Galactic NS-NS binary merger rate R_g among all known systems, solely based on the properties of the first-born, recycled pulsar (PSR J0737-3039A, or A) with an assumption for the beaming correction factor of 6. In this work, we carefully correct observational biases for the second-born, non-recycled pulsar (PSR J0737-0737B, or B) and estimate the contribution from the Double Pulsar on R_g using constraints available from both A and B. Observational constraints from the B pulsar favour a small beaming correction factor for A (˜2), which is consistent with a bipolar model. Considering known NS-NS binaries with the best observational constraints, including both A and B, we obtain R_g=21_{-14}^{+28} Myr-1 at 95 per cent confidence from our reference model. We expect the detection rate of gravitational waves from NS-NS inspirals for the advanced ground-based gravitational-wave detectors is to be 8^{+10}_{-5} yr-1 at 95 per cent confidence. Within several years, gravitational-wave detections relevant to NS-NS inspirals will provide us useful information to improve pulsar population models.
A complete waveform model for compact binaries on eccentric orbits

NASA Astrophysics Data System (ADS)

George, Daniel; Huerta, Eliu; Kumar, Prayush; Agarwal, Bhanu; Schive, Hsi-Yu; Pfeiffer, Harald; Chu, Tony; Boyle, Michael; Hemberger, Daniel; Kidder, Lawrence; Scheel, Mark; Szilagyi, Bela

2017-01-01

We present a time domain waveform model that describes the inspiral, merger and ringdown of compact binary systems whose components are non-spinning, and which evolve on orbits with low to moderate eccentricity. We show that this inspiral-merger-ringdown waveform model reproduces the effective-one-body model for black hole binaries with mass-ratios between 1 to 15 in the zero eccentricity limit over a wide range of the parameter space under consideration. We use this model to show that the gravitational wave transients GW150914 and GW151226 can be effectively recovered with template banks of quasicircular, spin-aligned waveforms if the eccentricity e0 of these systems when they enter the aLIGO band at a gravitational wave frequency of 14 Hz satisfies e0GW 150914 <= 0 . 15 and e0GW 151226 <= 0 . 1 .
Late-time X-ray signatures of compact binary mergers: potential counterparts of gravitational wave events

NASA Astrophysics Data System (ADS)

Tanvir, Nial

2017-09-01

Merging compact binaries (NS-NS or NS-BH) offer the best prospects for detection of EM signals accompanying gravitational wave (GW) events. They may be seen as bright short-GRBs (SGRBs), but this is likely to be rare due to beaming. Alternatively, more isotropic near-IR emission is predicted to result from the 'kilonova' produced by radioactive decay of neutron star ejecta. However, recent XMM observations have shown unexplained excess X-ray emission several days post-burst in two low-z SGRBs. This may indicate ongoing engine activity which both enhances the nIR emission, and crucially provides a potential new isotropic X-ray signature of compact binary mergers. We propose a detailed study of a further z<0.35 SGRB, to explore this phenomenon and inform future searches for GW counterparts.
Advances in Black-Hole Mergers: Spins and Unequal Masses

NASA Technical Reports Server (NTRS)

Kelly, Bernard

2007-01-01

The last two years have seen incredible development in numerical relativity: from fractions of an orbit, evolutions of an equal-mass binary have reached multiple orbits, and convergent gravitational waveforms have been produced from several research groups and numerical codes. We are now able to move our attention from pure numerics to astrophysics, and address scenarios relevant to current and future gravitational-wave detectors.Over the last 12 months at NASA Goddard, we have extended the accuracy of our Hahn-Dol code, and used it to move toward these goals. We have achieved high-accuracy simulations of black-hole binaries of low initial eccentricity, with enough orbits of inspiral before merger to allow us to produce hybrid waveforms that reflect accurately the entire lifetime of the BH binary. We are extending this work, looking at the effects of unequal masses and spins.
Constraining f(R) gravity in solar system, cosmology and binary pulsar systems

NASA Astrophysics Data System (ADS)

Liu, Tan; Zhang, Xing; Zhao, Wen

2018-02-01

The f (R) gravity can be cast into the form of a scalar-tensor theory, and scalar degree of freedom can be suppressed in high-density regions by the chameleon mechanism. In this article, for the general f (R) gravity, using a scalar-tensor representation with the chameleon mechanism, we calculate the parametrized post-Newtonian parameters γ and β, the effective gravitational constant Geff, and the effective cosmological constant Λeff. In addition, for the general f (R) gravity, we also calculate the rate of orbital period decay of the binary system due to gravitational radiation. Then we apply these results to specific f (R) models (Hu-Sawicki model, Tsujikawa model and Starobinsky model) and derive the constraints on the model parameters by combining the observations in solar system, cosmological scales and the binary systems.
KCTF evolution of trans-neptunian binaries: Connecting formation to observation

NASA Astrophysics Data System (ADS)

Porter, Simon B.; Grundy, William M.

2012-08-01

Recent observational surveys of trans-neptunian binary (TNB) systems have dramatically increased the number of known mutual orbits. Our Kozai Cycle Tidal Friction (KCTF) simulations of synthetic trans-neptunian binaries show that tidal dissipation in these systems can completely reshape their original orbits. Specifically, solar torques should have dramatically accelerated the semimajor axis decay and circularization timescales of primordial (or recently excited) TNBs. As a result, our initially random distribution of TNBs in our simulations evolved to have a large population of tight circular orbits. This tight circular population appears for a range of TNO physical properties, though a strong gravitational quadrupole can prevent some from fully circularizing. We introduce a stability parameter to predict the effectiveness of KCTF on a TNB orbit, and show that a number of known TNBs must have a large gravitational quadrupole to be stable.
GW170608: Observation of a 19 Solar-mass Binary Black Hole Coalescence

NASA Astrophysics Data System (ADS)

Abbott, B. P.; Abbott, R.; Abbott, T. D.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Afrough, M.; Agarwal, B.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allen, G.; Allocca, A.; Altin, P. A.; Amato, A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Angelova, S. V.; Antier, S.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Atallah, D. V.; Aufmuth, P.; Aulbert, C.; AultONeal, K.; Austin, C.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Bae, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Banagiri, S.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barkett, K.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bawaj, M.; Bayley, J. C.; Bazzan, M.; Bécsy, B.; Beer, C.; Bejger, M.; Belahcene, I.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Bero, J. J.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Biscoveanu, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackman, J.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bode, N.; Boer, M.; Bogaert, G.; Bohe, A.; Bondu, F.; Bonilla, E.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bossie, K.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T. A.; Calloni, E.; Camp, J. B.; Canepa, M.; Canizares, P.; Cannon, K. C.; Cao, H.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Carney, M. F.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerdá-Durán, P.; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chase, E.; Chassande-Mottin, E.; Chatterjee, D.; Chatziioannou, K.; Cheeseboro, B. D.; Chen, H. Y.; Chen, X.; Chen, Y.; Cheng, H.-P.; Chia, H.; Chincarini, A.; Chiummo, A.; Chmiel, T.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, A. J. K.; Chua, S.; Chung, A. K. W.; Chung, S.; Ciani, G.; Ciolfi, R.; Cirelli, C. E.; Cirone, A.; Clara, F.; Clark, J. A.; Clearwater, P.; Cleva, F.; Cocchieri, C.; Coccia, E.; Cohadon, P.-F.; Cohen, D.; Colla, A.; Collette, C. G.; Cominsky, L. 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J.; Masso-Reid, M.; Mastrogiovanni, S.; Matas, A.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McCuller, L.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McNeill, L.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Mejuto-Villa, E.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, B. B.; Miller, J.; Millhouse, M.; Milovich-Goff, M. C.; Minazzoli, O.; Minenkov, Y.; Ming, J.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moffa, D.; Moggi, A.; Mogushi, K.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. 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V.; Toland, K.; Tonelli, M.; Tornasi, Z.; Torres-Forné, A.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trinastic, J.; Tringali, M. C.; Trozzo, L.; Tsang, K. W.; Tse, M.; Tso, R.; Tsukada, L.; Tsuna, D.; Tuyenbayev, D.; Ueno, K.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Varma, V.; Vass, S.; Vasúth, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Venugopalan, G.; Verkindt, D.; Vetrano, F.; Viceré, A.; Viets, A. D.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walet, R.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, J. Z.; Wang, W. H.; Wang, Y. F.; Ward, R. L.; Warner, J.; Was, M.; Watchi, J.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessel, E. K.; Weßels, P.; Westerweck, J.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Whittle, C.; Wilken, D.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Wofford, J.; Wong, K. W. K.; Worden, J.; Wright, J. L.; Wu, D. S.; Wysocki, D. M.; Xiao, S.; Yamamoto, H.; Yancey, C. C.; Yang, L.; Yap, M. J.; Yazback, M.; Yu, Hang; Yu, Haocun; Yvert, M.; Zadrożny, A.; Zanolin, M.; Zelenova, T.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, T.; Zhang, Y.-H.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, S. J.; Zhu, X. J.; Zimmerman, A. B.; Zucker, M. E.; Zweizig, J.; (LIGO Scientific Collaboration; Virgo Collaboration

2017-12-01

On 2017 June 8 at 02:01:16.49 UTC, a gravitational-wave (GW) signal from the merger of two stellar-mass black holes was observed by the two Advanced Laser Interferometer Gravitational-Wave Observatory detectors with a network signal-to-noise ratio of 13. This system is the lightest black hole binary so far observed, with component masses of {12}-2+7 {M}ȯ and {7}-2+2 {M}ȯ (90% credible intervals). These lie in the range of measured black hole masses in low-mass X-ray binaries, thus allowing us to compare black holes detected through GWs with electromagnetic observations. The source’s luminosity distance is {340}-140+140 {Mpc}, corresponding to redshift {0.07}-0.03+0.03. We verify that the signal waveform is consistent with the predictions of general relativity.
Gravitational lensing in quasar samples

NASA Astrophysics Data System (ADS)

Claeskens, Jean-François; Surdej, Jean

The first cosmic mirage was discovered approximately 20 years ago as the double optical counterpart of a radio source. This phenomenon had been predicted some 70 years earlier as a consequence of General Relativity. We present here a summary of what we have learnt since. The applications are so numerous that we had to concentrate on a few selected aspects of this new field of research. This review is focused on strong gravitational lensing, i.e. the formation of multiple images, in QSO samples. It is intended to give the reader an up-to-date status of the observations and to present an overview of its most interesting potential applications in cosmology and astrophysics, as well as numerous important results achieved so far. The first section follows an intuitive approach to the basics of gravitational lensing and is developed in view of our interest in multiply imaged quasars. The astrophysical and cosmological applications of gravitational lensing are outlined in Sect. 2 and the most important results are presented in Sect. 5. Sections 3 and 4 are devoted to the observations. Finally, conclusions are summarized in the last section. We have tried to avoid duplication with existing (and excellent) introductions to the field of gravitational lensing. For this reason, we did not concentrate on the individual properties of specific lens models, as these are already well presented in Narayan and Bartelmann (1996) and on a more intuitive ground in Refsdal and Surdej (1994). Wambsganss (1998) proposes a broad view on gravitational lensing in astronomy; the reviews by Fort and Mellier (1994) and Hattori et al. (1999) deal with lensing by galaxy clusters; microlensing in the Galaxy and the local group is reviewed by Paczynski (1996) and a general panorama on weak lensing is given by Bartelmann and Schneider (1999) and Mellier (1999). The monograph on the theory of gravitational lensing by Schneider, Ehlers and Falco (1992) also remains a reference in the field.
Results from Binary Black Hole Simulations in Astrophysics Applications

NASA Technical Reports Server (NTRS)

Baker, John G.

2007-01-01

Present and planned gravitational wave observatories are opening a new astronomical window to the sky. A key source of gravitational waves is the merger of two black holes. The Laser Interferometer Space Antenna (LISA), in particular, is expected to observe these events with signal-to-noise ratio's in the thousands. To fully reap the scientific benefits of these observations requires a detailed understanding, based on numerical simulations, of the predictions of General Relativity for the waveform signals. New techniques for simulating binary black hole mergers, introduced two years ago, have led to dramatic advances in applied numerical simulation work. Over the last two years, numerical relativity researchers have made tremendous strides in understanding the late stages of binary black hole mergers. Simulations have been applied to test much of the basic physics of binary black hole interactions, showing robust results for merger waveform predictions, and illuminating such phenomena as spin-precession. Calculations have shown that merging systems can be kicked at up to 2500 km/s by the thrust from asymmetric emission. Recently, long lasting simulations of ten or more orbits allow tests of post-Newtonian (PN) approximation results for radiation from the last orbits of the binary's inspiral. Already, analytic waveform models based PN techniques with incorporated information from numerical simulations may be adequate for observations with current ground based observatories. As new advances in simulations continue to rapidly improve our theoretical understanding of the systems, it seems certain that high-precision predictions will be available in time for LISA and other advanced ground-based instruments. Future gravitational wave observatories are expected to make precision.

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