Multiwavelength monitoring and X-ray brightening of Be X-ray binary PSR J2032+4127/MT91 213 on its approach to periastron

DOE PAGES

Ho, Wynn C. G.; Ng, C. -Y.; Lyne, Andrew G.; ...

2016-09-22

The radio and gamma-ray pulsar PSR J2032+4127 was recently found to be in a decades-long orbit with the Be star MT91 213, with the pulsar moving rapidly towards periastron. This binary shares many similar characteristics with the previously unique binary system PSR B1259-63/LS 2883. Here in this paper, we describe radio, X-ray, and optical monitoring of PSR J2032+4127/MT91 213. Our extended orbital phase coverage in radio, supplemented with Fermi LAT gamma-ray data, allows us to update and refine the orbital period to 45–50 yr and time of periastron passage to 2017 November. We analyse archival and recent Chandra and Swiftmore » observations and show that PSR J2032+4127/MT91 213 is now brighter in X-rays by a factor of ~70 since 2002 and ~20 since 2010. While the pulsar is still far from periastron, this increase in X-rays is possibly due to collisions between pulsar and Be star winds. Optical observations of the Hα emission line of the Be star suggest that the size of its circumstellar disc may be varying by ~2 over time-scales as short as 1–2 months. In conclusion, multiwavelength monitoring of PSR J2032+4127/MT91 213 will continue through periastron passage, and the system should present an interesting test case and comparison to PSR B1259-63/LS 2883.« less

Tidal tearing of circumstellar disks in Be/X-ray and gamma-ray binaries

NASA Astrophysics Data System (ADS)

Okazaki, Atsuo T.

2017-11-01

About one half of high-mass X-ray binaries host a Be star [an OB star with a viscous decretion (slowly outflowing) disk]. These Be/X-ray binaries exhibit two types of X-ray outbursts (Stella et al. 1986), normal X-ray outbursts (L X~1036-37 erg s-1) and occasional giant X-ray outbursts (L X > 1037 erg s-1). The origin of giant X-ray outbursts is unknown. On the other hand, a half of gamma-ray binaries have a Be star as the optical counterpart. One of these systems [LS I +61 303 (P orb = 26.5 d)] shows the superorbital (1,667 d) modulation in radio through X-ray bands. No consensus has been obtained for its origin. In this paper, we study a possibility that both phenomena are caused by a long-term, cyclic evolution of a highly misaligned Be disk under the influence of a compact object, by performing 3D hydrodynamic simulations. We find that the Be disk cyclically evolves in mildly eccentric, short-period systems. Each cycle consists of the following stages: 1) As the Be disk grows with time, the initially circular disk becomes eccentric by the Kozai-Lidov mechanism. 2) At some point, the disk is tidally torn off near the base and starts precession. 3) Due to precession, a gap opens between the disk base and mass ejection region, which allows the formation of a new disk in the stellar equatorial plane (see Figure 1). 4) The newly formed disk finally replaces the precessing old disk. Such a cyclic disk evolution has interesting implications for the long-term behavior of high energy emission in Be/X-ray and gamma-ray binaries.

Fermi LAT Observations of LS I +61 303: First Detection of an Orbital Modulation in GeV Gamma Rays

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

Abdo, A.A.; /Federal City Coll. /Naval Research Lab, Wash., D.C.; Ackermann, M.

This Letter presents the first results from the observations of LS I +61{sup o}303 using Large Area Telescope data from the Fermi Gamma-Ray Space Telescope between 2008 August and 2009 March. Our results indicate variability that is consistent with the binary period, with the emission being modulated at 26.6 {+-} 0.5 days. This constitutes the first detection of orbital periodicity in high-energy gamma rays (20 MeV-100 GeV, HE). The light curve is characterized by a broad peak after periastron, as well as a smaller peak just before apastron. The spectrum is best represented by a power law with an exponentialmore » cutoff, yielding an overall flux above 100 MeV of 0.82 {+-} 0.03(stat) {+-} 0.07(syst) 10{sup -6} ph cm{sup -2} s{sup -1}, with a cutoff at 6.3 {+-} 1.1(stat) {+-} 0.4(syst) GeV and photon index {Gamma} = 2.21 {+-} 0.04(stat) {+-} 0.06(syst). There is no significant spectral change with orbital phase. The phase of maximum emission, close to periastron, hints at inverse Compton scattering as the main radiation mechanism. However, previous very high-energy gamma ray (>100 GeV, VHE) observations by MAGIC and VERITAS show peak emission close to apastron. This and the energy cutoff seen with Fermi suggest that the link between HE and VHE gamma rays is nontrivial.« less

Fermi LAT Observations of LS 5039

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

Abdo, A.A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.

The first results from observations of the high-mass X-ray binary LS 5039 using the Fermi Gamma-ray Space Telescope data between 2008 August and 2009 June are presented. Our results indicate variability that is consistent with the binary period, with the emission being modulated with a period of 3.903 {+-} 0.005 days; the first detection of this modulation at GeV energies. The light curve is characterized by a broad peak around superior conjunction in agreement with inverse Compton scattering models. The spectrum is represented by a power law with an exponential cutoff, yielding an overall flux (100 MeV-300 GeV) of 4.9more » {+-} 0.5(stat) {+-} 1.8(syst) x 10{sup -7} photon cm{sup -2} s{sup -1}, with a cutoff at 2.1 {+-} 0.3(stat) {+-} 1.1(syst) GeV and photon index {Gamma} = 1.9 {+-} 0.1(stat) {+-} 0.3(syst). The spectrum is observed to vary with orbital phase, specifically between inferior and superior conjunction. We suggest that the presence of a cutoff in the spectrum may be indicative of magnetospheric emission similar to the emission seen in many pulsars by Fermi.« less

Gamma-ray flare activity from PSR B1259-63 during 2014 Periastron Passage and comparison to its 2010 passage

DOE PAGES

Caliandro, G. A.; Cheung, C. C.; Li, J.; ...

2015-09-22

PSR B1259–63/LS 2883 is a gamma-ray binary system containing a radio pulsar in a highly elliptical ~3.4-year orbit around a Be star. In its 2010 periastron passage, multiwavelength emission from radio to TeV was observed, as well as an unexpected GeV flare measured by the Fermi Large Area Telescope (LAT). We report the results of LAT monitoring of PSR B1259–63 during its most recent 2014 periastron passage. We also compare the gamma-ray behavior in this periastron with the former in 2010 and find that PSR B1259–63 shows a recurrent GeV flare. Furthermore, the similarities and differences in the phenomenology ofmore » both periastron passages are discussed.« less

GAMMA-RAY FLARE ACTIVITY FROM PSR B1259–63 DURING 2014 PERIASTRON PASSAGE AND COMPARISON TO ITS 2010 PASSAGE

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

Caliandro, G. A.; Cheung, C. C.; Wood, K. S.

2015-09-20

PSR B1259–63/LS 2883 is a gamma-ray binary system containing a radio pulsar in a highly elliptical ∼3.4-year orbit around a Be star. In its 2010 periastron passage, multiwavelength emission from radio to TeV was observed, as well as an unexpected GeV flare measured by the Fermi Large Area Telescope (LAT). Here, we report the results of LAT monitoring of PSR B1259–63 during its most recent 2014 periastron passage. We compare the gamma-ray behavior in this periastron with the former in 2010 and find that PSR B1259–63 shows a recurrent GeV flare. The similarities and differences in the phenomenology of bothmore » periastron passages are discussed.« less

The 2017 Periastron Passage of PSR B1259-63 in Gamma-rays and X-rays

NASA Astrophysics Data System (ADS)

Wood, Kent S.; Johnson, Tyrel; Ray, Paul S.; Kerr, Matthew T.; Chernyakova, Masha; Fermi LAT Collaboration

2018-01-01

PSR B1259‑ 63 is a 48-ms radio pulsar in a highly eccentric 3.4-yr orbit with a Be star LS 2883. While the pulsed emission has been detected only in radio, un-pulsed radio, X-ray and gamma-ray emission are regularly observed from the binary system around the periastron. It is likely that the collision of the pulsar wind with the anisotropic wind of the Be star plays a crucial role in the generation of the observed non-thermal emission. The spectral energy distribution observed near periastron peaks in GeV gamma-rays, reaching maximum flux several weeks past periastron. In September 2017 it is being observed for a third periastron passage by the Fermi satellite. Here we present first results of the 2017 multi-wavelength campaign. The 2017 observations are compared to the two previous cycles, and used to test current models. Until recently there was no similar source known in the Galaxy but now a near-twin to it, PSR J2032+4127 , (Pspin=143 ms, Porbit ~50 yr, detectable radio to gamma rays) has been found, and is also undergoing periastron passage in Nov 2017. Gamma-ray and X-ray phenomena in the two sources are compared and discussed. These objects may represent a transitional phase, with possible later phases being accreting pulsars, and eventually perhaps NS-BH or NS-NS binary systems. Portions of this research performed at the US Naval Research Laboratory are sponsored by NASA DPR S-15633-Y.

Fermi LAT Observations of LS I +61°303: First Detection of an Orbital Modulation in GeV Gamma Rays

DOE PAGES

Abdo, A. A.; Ackermann, M.; Ajello, M.; ...

2009-08-10

This paper presents the first results from the observations of LS I +61°303 using Large Area Telescope data from the Fermi Gamma-Ray Space Telescope between 2008 August and 2009 March. Our results indicate variability that is consistent with the binary period, with the emission being modulated at 26.6 ± 0.5 days. This constitutes the first detection of orbital periodicity in high-energy gamma rays (20 MeV-100 GeV, HE). The light curve is characterized by a broad peak after periastron, as well as a smaller peak just before apastron. The spectrum is best represented by a power law with an exponential cutoff,more » yielding an overall flux above 100 MeV of 0.82 ± 0.03(stat) ± 0.07(syst) 10 –6 ph cm –2 s –1, with a cutoff at 6.3 ± 1.1(stat) ± 0.4(syst) GeV and photon index Γ = 2.21 ± 0.04(stat) ± 0.06(syst). There is no significant spectral change with orbital phase. The phase of maximum emission, close to periastron, hints at inverse Compton scattering as the main radiation mechanism. However, previous very high-energy gamma ray (>100 GeV, VHE) observations by MAGIC and VERITAS show peak emission close to apastron. Finally, this and the energy cutoff seen with Fermi suggest that the link between HE and VHE gamma rays is nontrivial.« less

Gamma–Gamma Absorption in the γ-ray Binary System PSR B1259-63/LS 2883

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

Sushch, Iurii; Van Soelen, Brian, E-mail: iurii.sushch@desy.de, E-mail: vansoelenb@ufs.ac.za

2017-03-10

The observed TeV light curve from the γ -ray binary PSR B1259-63/LS 2883 shows a decrease in the flux at periastron that has not been fully explained by emission mechanisms alone. This observed decrease can, however, be explained by γγ absorption due to the stellar and disk photons. We calculate the γγ absorption in PSR B1259-63/LS 2883 taking into account photons from both the circumstellar disk and star, assuming that the γ -rays originate at the position of the pulsar. The γγ absorption due to the circumstellar disk photons produces a ≈14% decrease in the flux, and there is amore » total decrease of ≈52% (>1 TeV) within a few days before periastron, accompanied by a hardening of the γ -ray photon index. While the γγ absorption alone is not sufficient to explain the full complexity of the H.E.S.S. γ -ray light curve, it results in a significant decrease in the predicted flux, which is coincident with the observed decrease. In addition, we have calculated an upper limit on the γγ absorption, assuming that the emission is produced at the apex of the bow shock. Future observations with CTA during the 2021 periastron passage may be able to confine the location of the emission based on the degree of γγ absorption, as well as measure the hardening of the spectrum around periastron.« less

Periodic Emission from the Gamma-ray Binary 1FGL J1018.6-5856

NASA Technical Reports Server (NTRS)

Celic, O.; Corbet, R. H. D.; Donato, D.; Ferrara, E. C.; Gehrels, N.; Harding, A. K.; Hays, E.; McEnery, J. E.; Thompson, D. J.; Troja, E.

2012-01-01

Gamma-ray binaries are stellar systems containing a neutron star or black hole with gamma-ray emission produced by an interaction between the components. These systems are rare, even though binary evolution models predict dozens in our Galaxy. A search for gamma-ray binaries with the Fermi Large Area Telescope (LAT) shows that IFGL JI018.6-5856 exhibits intensity and spectral modulation with a 16.6 day period. We identified a variable X-ray counterpart, which shows a sharp maximum coinciding with maximum gamma-ray emission, as well as an 06V f) star optical counterpart and a radio counterpart that is also apparently modulated on the orbital period. IFGL J1018.6-5856 is thus a gamma-ray binary, and its detection suggests the presence of other fainter binaries in the Galaxy.

Periodic emission from the gamma-ray binary 1FGL J1018.6-5856.

PubMed

Fermi LAT Collaboration; Ackermann, M; Ajello, M; Ballet, J; Barbiellini, G; Bastieri, D; Belfiore, A; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Cavazzuti, E; Cecchi, C; Çelik, Ö; Charles, E; Chaty, S; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Corbel, S; Corbet, R H D; Cutini, S; de Luca, A; den Hartog, P R; de Palma, F; Dermer, C D; Digel, S W; do Couto e Silva, E; Donato, D; Drell, P S; Drlica-Wagner, A; Dubois, R; Dubus, G; Favuzzi, C; Fegan, S J; Ferrara, E C; Focke, W B; Fortin, P; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Grove, J E; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hill, A B; Hughes, R E; Jóhannesson, G; Johnson, A S; Johnson, T J; Kamae, T; Katagiri, H; Kataoka, J; Kerr, M; Knödlseder, J; Kuss, M; Lande, J; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Mazziotta, M N; McEnery, J E; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Naumann-Godo, M; Norris, J P; Nuss, E; Ohno, M; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ozaki, M; Paneque, D; Parent, D; Pesce-Rollins, M; Pierbattista, M; Piron, F; Pivato, G; Porter, T A; Rainò, S; Rando, R; Razzano, M; Reimer, A; Reimer, O; Ritz, S; Romani, R W; Roth, M; Saz Parkinson, P M; Sgrò, C; Siskind, E J; Spandre, G; Spinelli, P; Suson, D J; Takahashi, H; Tanaka, T; Thayer, J G; Thayer, J B; Thompson, D J; Tibaldo, L; Tinivella, M; Torres, D F; Tosti, G; Troja, E; Uchiyama, Y; Usher, T L; Vandenbroucke, J; Vianello, G; Vitale, V; Waite, A P; Winer, B L; Wood, K S; Wood, M; Yang, Z; Zimmer, S; Coe, M J; Di Mille, F; Edwards, P G; Filipović, M D; Payne, J L; Stevens, J; Torres, M A P

2012-01-13

Gamma-ray binaries are stellar systems containing a neutron star or black hole, with gamma-ray emission produced by an interaction between the components. These systems are rare, even though binary evolution models predict dozens in our Galaxy. A search for gamma-ray binaries with the Fermi Large Area Telescope (LAT) shows that 1FGL J1018.6-5856 exhibits intensity and spectral modulation with a 16.6-day period. We identified a variable x-ray counterpart, which shows a sharp maximum coinciding with maximum gamma-ray emission, as well as an O6V((f)) star optical counterpart and a radio counterpart that is also apparently modulated on the orbital period. 1FGL J1018.6-5856 is thus a gamma-ray binary, and its detection suggests the presence of other fainter binaries in the Galaxy.

Periodic Emission from the Gamma-Ray Binary 1FGL J1018.6-5856

NASA Technical Reports Server (NTRS)

2012-01-01

Gamma-ray binaries are stellar systems containing a neutron star or black hole, with gamma-ray emission produced by an interaction between the components. These systems are rare, even though binary evolution models predict dozens in our Galaxy, A search for gamma-ray binaries with the Fermi Large Area Telescope (LAT) shows that 1FGL ]1018.6-5856 exhibits intensity and spectral modulation with a 16.6 day period. We identified a variable x-ray counterpart, which shows a sharp maximum coinciding with maximum gamma-ray emission, as well as an O6V((f)) star optical counterpart and a radio counterpart that is also apparently modulated on the orbital period. 1FGL ]1018.6-5856 is thus a gamma-ray binary, and its detection suggests the presence of other fainter binaries in the Galaxy.

Post-periastron behavior of PSR J2032+4127/MT91 213: Outburst, jet, and winds

NASA Astrophysics Data System (ADS)

Ho, Wynn

2017-09-01

We propose 6x30 ks observations of the radio/gamma-ray pulsar PSR J2032+4127 and its companion Be-star MT91 213. This nearby pulsar is in a 49 yr orbit and will reach periastron 2017 November 13, when it will undergo an outburst if it accretes from a disk that surrounds the Be star. Our proposed observations allow us to (1) track the X-ray lightcurve and measure cooling of the neutron star crust, thus probing fundamental physics in extreme regimes. Irrespective of the outburst, our observations allow us to track (2) jet formation and (3) emission from the colliding winds of the two stars, thus serving as an important comparison to the only other gamma-ray pulsar in a Be-binary PSR B1259-63/LS 2883. These objectives require the long-term, high spatial resolution capabilities of Chandra.

LS 5039 - the counterpart of the unidentified MeV source GRO J1823-12

NASA Astrophysics Data System (ADS)

Collmar, W.; Zhang, S.

2014-05-01

Context. The COMPTEL experiment on CGRO observed the γ-ray sky at energies from 0.75 MeV to 30 MeV between April 1991 and June 2000. COMPTEL detected many γ-ray sources, among them an unidentified one labeled GRO J1823-12. It is located near l/b = 17.5°/-0.5° and positionally consistent with the prominent γ-ray binary LS 5039. Aims: LS 5039 was established as a γ-ray source at TeV energies by HESS and at GeV energies by Fermi/LAT during recent years, whose γ-ray radiation is modulated along its binary orbit. Given this new information we reanalyzed the COMPTEL data of GRO J1823-12 including an orbital-resolved analysis. Methods: We applied the standard methods, proper event selections and data binning with subsequent maximum-likelihood deconvolution, to analyze the COMPTEL data. In addition we developed a tool for selecting and binning the COMPTEL data in a phase-resolved manner. We present the orbit-averaged, as well as orbit-resolved MeV analyses, light curves, and spectra, and put them into a multifrequency context. Results: The COMPTEL data show a significant MeV source, which is positionally consistent with LS 5039, but also with other closeby Fermi/LAT sources. The orbit-resolved analysis provides strong evidence, at about the 3σ level, that the MeV flux of GRO J1823-12 is modulated along the binary orbit of about 3.9 days of LS 5039. We show that at MeV energies, the source is brighter at the orbital part around the inferior conjunction than at the part of the superior conjunction, so it is in phase with X-rays and TeV γ-rays, but in anti-phase with GeV γ-rays. The high-energy spectral energy distribution (X-rays to TeV γ-rays) shows the high-energy emission maximum of LS 5039 at MeV energies. Conclusions: We conclude that the COMPTEL source GRO J1823-12 is the counterpart of the microquasar LS 5039, at least for the majority of its MeV emission. The COMPTEL fluxes, put into multifrequency perspective, provide new constraints on the modeling of the high-energy emission pattern of the γ-ray binary LS 5039. Table 1 is available in electronic form at http://www.aanda.org

A MAGNETAR-LIKE EVENT FROM LS I +61 Degree-Sign 303 AND ITS NATURE AS A GAMMA-RAY BINARY

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

Torres, Diego F.; Rea, Nanda; Esposito, Paolo

2012-01-10

We report on the Swift Burst Alert Telescope detection of a short burst from the direction of the TeV binary LS I +61 Degree-Sign 303, resembling those generally labeled as magnetar-like. We show that it is likely that the short burst was indeed originating from LS I +61 Degree-Sign 303 (although we cannot totally exclude the improbable presence of a far-away, line-of-sight magnetar) and that it is a different phenomenon with respect to the previously observed ks-long flares from this system. Accepting the hypothesis that LS I +61 Degree-Sign 303 is the first magnetar detected in a binary system, wemore » study those implications. We find that a magnetar-composed LS I +61 Degree-Sign 303 system would most likely be (i.e., for the usual magnetar parameters and mass-loss rate) subject to a flip-flop behavior, from a rotationally powered regime (in the apastron) to a propeller regime (in the periastron) along each of the LS I +61 Degree-Sign 303 eccentric orbital motion. We prove that, unlike near an apastron, where an interwind shock can lead to the normally observed LS I +61 Degree-Sign 303 behavior, during TeV emission the periastron propeller is expected to efficiently accelerate particles only to sub-TeV energies. This flip-flop scenario would explain the system's behavior when a recurrent TeV emission only appears near the apastron, the anti-correlation of the GeV and TeV emission, and the long-term TeV variability (which seems correlated to LS I +61 Degree-Sign 303's super-orbital period), including the appearance of a low TeV state. Finally, we qualitatively put the multi-wavelength phenomenology into the context of our proposed model and make some predictions for further testing.« less

Periodic Emission from the Gamma-Ray Binary 1FGL J1018.6-5856

DOE PAGES

Ackermann, M.

2012-01-12

Gamma-ray binaries are stellar systems containing a neutron star or black hole with gamma-ray emission produced by an interaction between the components. These systems are rare, even though binary evolution models predict dozens in our Galaxy. A search for gamma-ray binaries with the Fermi Large Area Telescope (LAT) shows that 1FGL J1018.6-5856 exhibits intensity and spectral modulation with a 16.6 day period. We identified a variable X-ray counterpart, which shows a sharp maximum coinciding with maximum gamma-ray emission, as well as an O6V((f)) star optical counterpart and a radio counterpart that is also apparently modulated on the orbital period. 1FGLmore » J1018.6-5856 is thus a gamma-ray binary, and its detection suggests the presence of other fainter binaries in the Galaxy.« less

Sizing up the population of gamma-ray binaries

NASA Astrophysics Data System (ADS)

Dubus, Guillaume; Guillard, Nicolas; Petrucci, Pierre-Olivier; Martin, Pierrick

2017-12-01

Context. Gamma-ray binaries are thought to be composed of a young pulsar in orbit around a massive O or Be star with their gamma-ray emission powered by pulsar spin-down. The number of such systems in our Galaxy is not known. Aims: We aim to estimate the total number of gamma-ray binaries in our Galaxy and to evaluate the prospects for new detections in the GeV and TeV energy range, taking into account that their gamma-ray emission is modulated on the orbital period. Methods: We modelled the population of gamma-ray binaries and evaluated the fraction of detected systems in surveys with the Fermi-LAT (GeV), H.E.S.S., HAWC and CTA (TeV) using observation-based and synthetic template light curves. Results: The detected fraction depends more on the orbit-average flux than on the light-curve shape. Our best estimate for the number of gamma-ray binaries is 101-52+89 systems. A handful of discoveries are expected by pursuing the Fermi-LAT survey. Discoveries in TeV surveys are less likely. However, this depends on the relative amounts of power emitted in GeV and TeV domains. There could be as many as ≈ 200 HESS J0632+057-like systems with a high ratio of TeV to GeV emission compared to other gamma-ray binaries. Statistics allow for as many as three discoveries in five years of HAWC observations and five discoveries in the first two years of the CTA Galactic Plane survey. Conclusions: We favour continued Fermi-LAT observations over ground-based TeV surveys to find new gamma-ray binaries. Gamma-ray observations are most sensitive to short orbital period systems with a high spin-down pulsar power. Radio pulsar surveys (SKA) are likely to be more efficient in detecting long orbital period systems, providing a complementary probe into the gamma-ray binary population.

FERMI/LAT Observations of LS 5039

DOE PAGES

Abdo, A. A.; Ackermann, M.; Ajello, M.; ...

2009-10-30

The first results from observations of the high-mass X-ray binary LS 5039 using the Fermi Gamma-ray Space Telescope data between 2008 August and 2009 June are presented. In this report, our results indicate variability that is consistent with the binary period, with the emission being modulated with a period of 3.903 ± 0.005 days; the first detection of this modulation at GeV energies. The light curve is characterized by a broad peak around superior conjunction in agreement with inverse Compton scattering models. The spectrum is represented by a power law with an exponential cutoff, yielding an overall flux (100 MeV-300more » GeV) of 4.9 ± 0.5(stat) ± 1.8(syst) ×10 –7 photon cm –2 s –1, with a cutoff at 2.1 ± 0.3(stat) ± 1.1(syst) GeV and photon index Γ = 1.9 ± 0.1(stat) ± 0.3(syst). The spectrum is observed to vary with orbital phase, specifically between inferior and superior conjunction. Lastly, we suggest that the presence of a cutoff in the spectrum may be indicative of magnetospheric emission similar to the emission seen in many pulsars by Fermi.« less

Gamma-Ray Astronomy Technology Needs

NASA Technical Reports Server (NTRS)

Gehrels, N.; Cannizzo, J. K.

2012-01-01

In recent decades gamma-ray observations have become a valuable tool for studying the universe. Progress made in diverse 8re1lS such as gamma-ray bursts (GRBs), nucleosynthesis, and active galactic nuclei (AGNs) has complimented and enriched our astrophysical understanding in many ways. We present an overview of current and future planned space y-ray missions and discussion technology needs for- the next generation of space gamma-ray instruments.

The Gamma-ray Sky with Fermi

NASA Technical Reports Server (NTRS)

Thompson, David

2012-01-01

Gamma rays reveal extreme, nonthermal conditions in the Universe. The Fermi Gamma-ray Space Telescope has been exploring the gamma-ray sky for more than four years, enabling a search for powerful transients like gamma-ray bursts, novae, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as dark matter annihilation. Some results include a stringent limit on Lorentz invariance derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge gamma-ray structure associated with the center of our galaxy, surprising behavior from some gamma-ray binary systems, and a possible constraint on some WIMP models for dark matter.

The Gamma-ray Universe through Fermi

NASA Technical Reports Server (NTRS)

Thompson, David J.

2012-01-01

Gamma rays, the most powerful form of light, reveal extreme conditions in the Universe. The Fermi Gamma-ray Space Telescope and its smaller cousin AGILE have been exploring the gamma-ray sky for several years, enabling a search for powerful transients like gamma-ray bursts, novae, solar flares, and flaring active galactic nuclei, as well as long-term studies including pulsars, binary systems, supernova remnants, and searches for predicted sources of gamma rays such as dark matter annihilation. Some results include a stringent limit on Lorentz invariance derived from a gamma-ray burst, unexpected gamma-ray variability from the Crab Nebula, a huge ga.nuna-ray structure associated with the center of our galaxy, surprising behavior from some gamma-ray binary systems, and a possible constraint on some WIMP models for dark matter.

POSSIBLE CHANGES OF STATE AND RELEVANT TIMESCALES FOR A NEUTRON STAR IN LS I +61 Degree-Sign 303

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

Papitto, A.; Torres, D. F.; Rea, N.

2012-09-10

The properties of the short, energetic bursts recently observed from the {gamma}-ray binary LS I +61 Degree-Sign 303 are typical of those showed by high magnetic field neutron stars (NSs) and thus provide a strong indication in favor of a NS being the compact object in the system. Here, we discuss the transitions among the states accessible to a NS in a system like LS I +61 Degree-Sign 303, such as the ejector, propeller, and accretor phases, depending on the NS spin period, magnetic field, and rate of mass captured. We show how the observed bolometric luminosity ({approx}> few Multiplication-Signmore » 10{sup 35} erg s{sup -1}) and its broadband spectral distribution indicate that the compact object is most probably close to the transition between working as an ejector all along its orbit and being powered by the propeller effect when it is close to the orbit periastron, in a so-called flip-flop state. By assessing the torques acting onto the compact object in the various states, we follow the spin evolution of the system, evaluating the time spent by the system in each of them. Even taking into account the constraint set by the observed {gamma}-ray luminosity, we found that the total age of the system is compatible with being Almost-Equal-To 5-10 kyr, comparable to the typical spin-down ages of high-field NSs. The results obtained are discussed in the context of the various evolutionary stages expected for a NS with a high-mass companion.« less

A luminous gamma-ray binary in the large magellanic cloud

DOE PAGES

Corbet, R. H. D.; Chomiuk, L.; Coe, M. J.; ...

2016-09-27

Gamma-ray binaries consist of a neutron star or a black hole interacting with a normal star to produce gamma-ray emission that dominates the radiative output of the system. Previously, only a handful of such systems have been discovered, all within our Galaxy. We report the discovery of a luminous gamma-ray binary in the Large Magellanic Cloud, found with the Fermi Large Area Telescope (LAT), from a search for periodic modulation in all sources in the third Fermi LAT catalog. This is the first such system to be found outside the Milky Way. Furthermore, the system has an orbital period ofmore » 10.3 days, and is associated with a massive O5III star located in the supernova remnant DEM L241, previously identified as the candidate high-mass X-ray binary (HMXB) CXOU J053600.0–673507. X-ray and radio emission are also modulated on the 10.3 day period, but are in anti-phase with the gamma-ray modulation. Optical radial velocity measurements suggest that the system contains a neutron star. The source is significantly more luminous than similar sources in the Milky Way, at radio, optical, X-ray, and gamma-ray wavelengths. The detection of this extra-galactic system, but no new Galactic systems, raises the possibility that the predicted number of gamma-ray binaries in our Galaxy has been overestimated, and that HMXBs may be born containing relatively slowly rotating neutron stars.« less

Low-mass X-ray binaries and gamma-ray bursts

NASA Technical Reports Server (NTRS)

Lasota, J. P.; Frank, J.; King, A. R.

1992-01-01

More than twenty years after their discovery, the nature of gamma-ray burst sources (GRBs) remains mysterious. The results from BATSE experiment aboard the Compton Observatory show however that most of the sources of gamma-ray bursts cannot be distributed in the galactic disc. The possibility that a small fraction of sites of gamma-ray bursts is of galactic disc origin cannot however be excluded. We point out that large numbers of neutron-star binaries with orbital periods of 10 hr and M dwarf companions of mass 0.2-0.3 solar mass are a natural result of the evolution of low-mass X-ray binaries (LMXBs). The numbers and physical properties of these systems suggest that some gamma-ray burst sources may be identified with this endpoint of LMXB evolution. We suggest an observational test of this hypothesis.

What Can Simbol-X Do for Gamma-ray Binaries?

NASA Astrophysics Data System (ADS)

Cerutti, B.; Dubus, G.; Henri, G.; Hill, A. B.; Szostek, A.

2009-05-01

Gamma-ray binaries have been uncovered as a new class of Galactic objects in the very high energy sky (>100 GeV). The three systems known today have hard X-ray spectra (photon index ~1.5), extended radio emission and a high luminosity in gamma-rays. Recent monitoring campaigns of LSI +61°303 in X-rays have confirmed variability in these systems and revealed a spectral hardening with increasing flux. In a generic one-zone leptonic model, the cooling of relativistic electrons accounts for the main spectral and temporal features observed at high energy. Persistent hard X-ray emission is expected to extend well beyond 10 keV. We explain how Simbol-X will constrain the existing models in connection with Fermi Space Telescope measurements. Because of its unprecedented sensitivity in hard X-rays, Simbol-X will also play a role in the discovery of new gamma-ray binaries, giving new insights into the evolution of compact binaries.

Modulated high-energy gamma-ray emission from the microquasar Cygnus X-3.

PubMed

Abdo, A A; Ackermann, M; Ajello, M; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Celik, O; Chaty, S; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Corbel, S; Corbet, R; Dermer, C D; de Palma, F; Digel, S W; do Couto e Silva, E; Drell, P S; Dubois, R; Dubus, G; Dumora, D; Farnier, C; Favuzzi, C; Fegan, S J; Focke, W B; Fortin, P; Frailis, M; Fusco, P; Gargano, F; Gehrels, N; Germani, S; Giavitto, G; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hill, A B; Hjalmarsdotter, L; Horan, D; Hughes, R E; Jackson, M S; Jóhannesson, G; Johnson, A S; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kawai, N; Kerr, M; Knödlseder, J; Kocian, M L; Koerding, E; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Marchand, L; Marelli, M; Max-Moerbeck, W; Mazziotta, M N; McColl, N; McEnery, J E; Meurer, C; Michelson, P F; Migliari, S; Mitthumsiri, W; Mizuno, T; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Omodei, N; Ong, R A; Ormes, J F; Paneque, D; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piron, F; Pooley, G; Porter, T A; Pottschmidt, K; Rainò, S; Rando, R; Ray, P S; Razzano, M; Rea, N; Readhead, A; Reimer, A; Reimer, O; Richards, J L; Rochester, L S; Rodriguez, J; Rodriguez, A Y; Romani, R W; Ryde, F; Sadrozinski, H F-W; Sander, A; Saz Parkinson, P M; Sgrò, C; Siskind, E J; Smith, D A; Smith, P D; Spinelli, P; Starck, J-L; Stevenson, M; Strickman, M S; Suson, D J; Takahashi, H; Tanaka, T; Thayer, J B; Thompson, D J; Tibaldo, L; Tomsick, J A; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Vasileiou, V; Vilchez, N; Vitale, V; Waite, A P; Wang, P; Wilms, J; Winer, B L; Wood, K S; Ylinen, T; Ziegler, M

2009-12-11

Microquasars are accreting black holes or neutron stars in binary systems with associated relativistic jets. Despite their frequent outburst activity, they have never been unambiguously detected emitting high-energy gamma rays. The Fermi Large Area Telescope (LAT) has detected a variable high-energy source coinciding with the position of the x-ray binary and microquasar Cygnus X-3. Its identification with Cygnus X-3 is secured by the detection of its orbital period in gamma rays, as well as the correlation of the LAT flux with radio emission from the relativistic jets of Cygnus X-3. The gamma-ray emission probably originates from within the binary system, opening new areas in which to study the formation of relativistic jets.

A Gamma-Ray Burst Model Via Compressional Heating of Binary Neutron Stars

NASA Astrophysics Data System (ADS)

Salmonson, J. D.; Wilson, J. R.; Mathews, G. J.

1998-12-01

We present a model for gamma-ray bursts based on the compression of neutron stars in close binary systems. General relativistic (GR) simulations of close neutron star binaries have found compression of the neutron stars estimated to produce 1053 ergs of thermal neutrinos on a timescale of seconds. The hot neutron stars will emit neutrino pairs which will partially recombine to form 1051 to 1052 ergs of electron-positron (e^-e^+) pair plasma. GR hydrodynamic computational modeling of the e^-e^+ plasma flow and recombination yield a gamma-ray burst in good agreement with general characteristics (duration ~10 seconds, spectrum peak energy ~100 keV, total energy ~1051 ergs) of many observed gamma-ray bursts.

Modeling X-ray and gamma-ray emission in the intrabinary shock of pulsar binaries

NASA Astrophysics Data System (ADS)

An, H.

2017-10-01

We present broadband SED and light curve, and a wind interaction model for the gamma-ray binary 1FGL J1018.6-5856 (J1018) which exhibits double peaks in the X-ray light curve. Assuming that the X-ray to low-energy gamma-ray emission is produced by synchrotron radiation and high-energy gamma rays by inverse Compton scattering in the intrabinary shock (IBS), we model the broadband SED and light curve of J1018 using a two-component model having slow electrons in the shock and fast bulk-accelerated electrons at the skin of the shock. The model explains the broadband SED and light curve of J1018 qualitatively well. In particular, modeling the synchrotron emission constrains the orbital geometry. We discuss potential use of the model for other pulsar binaries.

Gamma rays from hidden millisecond pulsars

NASA Technical Reports Server (NTRS)

Tavani, Marco

1992-01-01

The properties were studied of a new class of gamma ray sources consisting of millisecond pulsars totally or partially surrounded by evaporating material from irradiated companion stars. Hidden millisecond pulsars offer a unique possibility to study gamma ray, optical and radio emission from vaporizing binaries. The relevance of this class of binaries for GRO observations and interpretation of COS-B data is emphasized.

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

Corbet, R. H. D.; Chomiuk, L.; Strader, J.

Gamma-ray binaries consist of a neutron star or a black hole interacting with a normal star to produce gamma-ray emission that dominates the radiative output of the system. Only a handful of such systems have been previously discovered, all within our Galaxy. Here, we report the discovery of a luminous gamma-ray binary in the Large Magellanic Cloud, found with the Fermi Large Area Telescope (LAT), from a search for periodic modulation in all sources in the third Fermi LAT catalog. This is the first such system to be found outside the Milky Way. The system has an orbital period ofmore » 10.3 days, and is associated with a massive O5III star located in the supernova remnant DEM L241, previously identified as the candidate high-mass X-ray binary (HMXB) CXOU J053600.0–673507. X-ray and radio emission are also modulated on the 10.3 day period, but are in anti-phase with the gamma-ray modulation. Optical radial velocity measurements suggest that the system contains a neutron star. The source is significantly more luminous than similar sources in the Milky Way, at radio, optical, X-ray, and gamma-ray wavelengths. The detection of this extra-galactic system, but no new Galactic systems, raises the possibility that the predicted number of gamma-ray binaries in our Galaxy has been overestimated, and that HMXBs may be born containing relatively slowly rotating neutron stars.« less

A New Approach to the GeV Flare of PSR B1259-63/LS2883

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

Yi, Shu-Xu; Cheng, K. S., E-mail: yishuxu@hku.hk, E-mail: hrspksc@hku.hk

2017-08-01

PSR B1259-63/LS2883 is a binary system composed of a pulsar and a Be star. The Be star has an equatorial circumstellar disk (CD). The Fermi satellite discovered unexpected gamma-ray flares around 30 days after the last two periastron passages. The origin of the flares remains puzzling. In this work, we explore the possibility that the GeV flares are consequences of inverse Compton scattering of soft photons by the pulsar wind. The soft photons are from an accretion disk around the pulsar, which is composed of the matter from the CD captured by the pulsar’s gravity at disk-crossing before the periastron.more » At the other disk-crossing after the periastron, the density of the CD is not high enough, so accretion is prevented by the pulsar wind shock. This model can reproduce the observed spectrum energy distributions and light curves satisfactorily.« less

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

Takata, J.; Tam, P. H. T.; Ng, C. W.

PSR J2032+4127 is a radio-loud gamma-ray-emitting pulsar; it is orbiting around a high-mass Be type star with a very long orbital period of 25–50 years, and is approaching periastron, which will occur in late 2017/early 2018. This system comprises a young pulsar and a Be type star, which is similar to the so-called gamma-ray binary PSR B1259–63/LS2883. It is expected therefore that PSR J2032+4127 shows an enhancement of high-energy emission caused by the interaction between the pulsar wind and Be wind/disk around periastron. Ho et al. recently reported a rapid increase in the X-ray flux from this system. In thismore » paper, we also confirm a rapid increase in the X-ray flux along the orbit, while the GeV flux shows no significant change. We discuss the high-energy emissions from the shock caused by the pulsar wind and stellar wind interaction and examine the properties of the pulsar wind in this binary system. We argue that the rate of increase of the X-ray flux observed by Swift indicates (1) a variation of the momentum ratio of the two-wind interaction region along the orbit, or (2) an evolution of the magnetization parameter of the pulsar wind with the radial distance from the pulsar. We also discuss the pulsar wind/Be disk interaction at the periastron passage, and propose the possibility of formation of an accretion disk around the pulsar. We model high-energy emissions through the inverse-Compton scattering process of the cold-relativistic pulsar wind off soft photons from the accretion disk.« less

The 4U 0115+63: Another energetic gamma ray binary pulsar

NASA Technical Reports Server (NTRS)

Chadwick, P. M.; Dipper, N. A.; Dowthwaite, J. C.; Kirkman, I. W.; Mccomb, T. J. L.; Orford, K. J.; Turver, K. E.

1985-01-01

Following the discovery of Her X-1 as a source of pulsed 1000 Gev X-rays, a search for emission from an X-ray binary containing a pulsar with similar values of period, period derivative and luminosity was successful. The sporadic X-ray binary 4U 0115-63 has been observed, with probability 2.5 x 10 to the minus 6 power ergs/s to emit 1000 GeV gamma-rays with a time averaged energy flux of 6 to 10 to the 35th power.

Simultaneous long-term monitoring of LS I +61°303 by OVRO and Fermi-LAT

NASA Astrophysics Data System (ADS)

Jaron, Frédéric; Massi, Maria; Kiehlmann, Sebastian; Hovatta, Talvikki

2018-07-01

Previous long-term monitorings of the γ-ray-loud X-ray binary LS I +61°303 have revealed the presence of a long-term modulation of ˜4.5 yr. After 9 yr of simultaneous monitoring of LS I +61°303 by the Owens Valley Radio Observatory and the Fermi-LAT, two cycles of the long-term period are now available. Here we perform timing analysis on the radio and the γ-ray light curves. We confirm the presence of previously detected periodicities at both radio and GeV γ-ray wavelengths. Moreover, we discover an offset of the long-term modulation between radio and γ-ray data which could imply different locations of the radio (15 GHz) and GeV emission along the precessing jet.

Binary Orbits as the Driver of Gamma-Ray Emission and Mass Ejection in Classical Novae

NASA Technical Reports Server (NTRS)

Chomiuk, Laura; Linford, Justin D.; Yang, Jun; O'Brien, T. J.; Paragi, Zsolt; Mioduszewski, Amy J.; Beswick, R. J.; Cheung, C. C.; Mukai, Koji; Nelson, Thomas

2014-01-01

Classical novae are the most common astrophysical thermonuclear explosions, occurring on the surfaces of white dwarf stars accreting gas from companions in binary star systems. Novae typically expel about 10 (sup -4) solar masses of material at velocities exceeding 1,000 kilometers per second.However, the mechanism of mass ejection in novae is poorly understood, and could be dominated by the impulsive flash of thermonuclear energy, prolonged optically thick winds or binary interaction with the nova envelope. Classical novae are now routinely detected at giga-electronvolt gamma-ray wavelengths, suggesting that relativistic particles are accelerated by strong shocks in the ejecta. Here we report high-resolution radio imaging of the gamma-ray-emitting nova V959 Mon. We find that its ejecta were shaped by the motion of the binary system: some gas was expelled rapidly along the poles as a wind from the white dwarf, while denser material drifted out along the equatorial plane, propelled by orbital motion..At the interface between the equatorial and polar regions, we observe synchrotron emission indicative of shocks and relativistic particle acceleration, thereby pinpointing the location of gamma-ray production. Binary shaping of the nova ejecta and associated internal shocks are expected to be widespread among novae, explaining why many novae are gamma-ray emitters.

HESS J1844-030: A New Gamma-Ray Binary?

NASA Astrophysics Data System (ADS)

McCall, Hannah; Errando, Manel

2018-01-01

Gamma-ray binaries are comprised of a massive, main-sequence star orbiting a neutron star or black hole that generates bright gamma-ray emission. Only six of these systems have been discovered. Here we report on a candidate stellar-binary system associated with the unidentified gamma-ray source HESS J1844-030, whose detection was revealed in the H.E.S.S. galactic plane survey. Analysis of 60 ks of archival Chandra data and over 100 ks of XMM-Newton data reveal a spatially associated X-ray counterpart to this TeV-emitting source (E>1012 eV), CXO J1845-031. The X-ray spectra derived from these exposures yields column density absorption in the range nH = (0.4 - 0.7) x 1022 cm-2, which is below the total galactic value for that part of the sky, indicating that the source is galactic. The flux from CXO J1845-031 increases with a factor of up to 2.5 in a 60 day timescale, providing solid evidence for flux variability at a confidence level exceeding 7 standard deviations. The point-like nature of the source, the flux variability of the nearby X-ray counterpart, and the low column density absorption are all indicative of a binary system. Once confirmed, HESS J1844-030 would represent only the seventh known gamma-ray binary, providing valuable data to advance our understanding of the physics of pulsars and stellar winds and testing high-energy astrophysical processes at timescales not present in other classes of objects.

1FGL J1417.7-4407: A Likely Gamma-Ray Bright Binary with A Massive Neutron Star and A Giant Secondary

NASA Technical Reports Server (NTRS)

Strader, Jay; Chomiuk, Laura; Cheung, C. C.; Sand, David J.; Donato, Davide; Corbet, Robin H. D.; Koeppe, Dana; Edwards, Philip G.; Stevens, Jamie; Petrov, Leonid

2015-01-01

We present multiwavelength observations of the persistent Fermi-Large Area Telescope unidentified gamma-ray source 1FGL J1417.7-4407, showing it is likely to be associated with a newly discovered X-ray binary containing a massive neutron star (nearly 2 solar mass) and a approximately 0.35 solar mass giant secondary with a 5.4 day period. SOAR optical spectroscopy at a range of orbital phases reveals variable double-peaked H alpha emission, consistent with the presence of an accretion disk. The lack of radio emission and evidence for a disk suggests the gamma-ray emission is unlikely to originate in a pulsar magnetosphere, but could instead be associated with a pulsar wind, relativistic jet, or could be due to synchrotron self-Compton at the disk-magnetosphere boundary. Assuming a wind or jet, the high ratio of gamma- ray to X-ray luminosity (approximately 20) suggests efficient production of gamma-rays, perhaps due to the giant companion. The system appears to be a low-mass X-ray binary that has not yet completed the pulsar recycling process. This system is a good candidate to monitor for a future transition between accretion-powered and rotational-powered states, but in the context of a giant secondary.

Research in astrophysical processes

NASA Technical Reports Server (NTRS)

Ruderman, Malvin A.

1994-01-01

Work completed under this grant is summarized in the following areas:(1) radio pulsar turn on and evaporation of companions in very low mass x-ray binaries and in binary radio pulsar systems; (2) effects of magnetospheric pair production on the radiation from gamma-ray pulsars; (3) radiation transfer in the atmosphere of an illuminated companion star; (4) evaporation of millisecond pulsar companions;(5) formation of planets around pulsars; (6) gamma-ray bursts; (7) quasi-periodic oscillations in low mass x-ray binaries; (8) origin of high mass x-ray binaries, runaway OB stars, and the lower mass cutoff for core collapse supernovae; (9) dynamics of planetary atmospheres; (10) two point closure modeling of stationary, forced turbulence; (11) models for the general circulation of Saturn; and (12) compressible convection in stellar interiors.

Gamma rays from pulsar wind shock acceleration

NASA Technical Reports Server (NTRS)

Harding, Alice K.

1990-01-01

A shock forming in the wind of relativistic electron-positron pairs from a pulsar, as a result of confinement by surrounding material, could convert part of the pulsar spin-down luminosity to high energy particles through first order Fermi acceleration. High energy protons could be produced by this mechanism both in supernova remnants and in binary systems containing pulsars. The pion-decay gamma-rays resulting from interaction of accelerated protons with surrounding target material in such sources might be observable above 70 MeV with EGRET (Energetic Gamma-Ray Experimental Telescope) and above 100 GeV with ground-based detectors. Acceleration of protons and expected gamma-ray fluxes from SN1987A, Cyg X-3 type sources and binary pulsars are discussed.

Constraints on Short, Hard Gamma-Ray Burst Beaming Angles from Gravitational Wave Observations

NASA Astrophysics Data System (ADS)

Williams, D.; Clark, J. A.; Williamson, A. R.; Heng, I. S.

2018-05-01

The first detection of a binary neutron star merger, GW170817, and an associated short gamma-ray burst confirmed that neutron star mergers are responsible for at least some of these bursts. The prompt gamma-ray emission from these events is thought to be highly relativistically beamed. We present a method for inferring limits on the extent of this beaming by comparing the number of short gamma-ray bursts (SGRBs) observed electromagnetically with the number of neutron star binary mergers detected in gravitational waves. We demonstrate that an observing run comparable to the expected Advanced LIGO (aLIGO) 2016–2017 run would be capable of placing limits on the beaming angle of approximately θ \\in (2\\buildrel{\\circ}\\over{.} 88,14\\buildrel{\\circ}\\over{.} 15), given one binary neutron star detection, under the assumption that all mergers produce a gamma-ray burst, and that SGRBs occur at an illustrative rate of {{ \\mathcal R }}grb}=10 {Gpc}}-3 {yr}}-1. We anticipate that after a year of observations with aLIGO at design sensitivity in 2020, these constraints will improve to θ \\in (8\\buildrel{\\circ}\\over{.} 10,14\\buildrel{\\circ}\\over{.} 95), under the same efficiency and SGRB rate assumptions.

Highlights of GeV Gamma-Ray Astronomy

NASA Technical Reports Server (NTRS)

Thompson, David J.

2010-01-01

Because high-energy gamma rays are primarily produced by high-energy particle interactions, the gamma-ray survey of the sky by the Fermi Gamma-ray Space Telescope offers a view of sites of cosmic ray production and interactions. Gamma-ray bursts, pulsars, pulsar wind nebulae, binary sources, and Active Galactic Nuclei are all phenomena that reveal particle acceleration through their gamma-ray emission. Diffuse Galactic gamma radiation, Solar System gamma-ray sources, and energetic radiation from supernova remnants are likely tracers of high-energy particle interactions with matter and photon fields. This paper will present a broad overview of the constantly changing sky seen with the Large Area Telescope (LAT) on the Fermi spacecraft.

Fermi GBM: Highlights from the First Year

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.

2009-01-01

The Fermi Gamma ray Burst Monitor is an all-sky instrument sensitive to photons from about 8 keV to 40 MeV. I will summarize highlights from the first year, including triggered observations of gamma ray bursts, soft gamma ray repeaters, and terrestrial gamma flashes, and observations in the continuous data of X-ray binaries and accreting X-ray pulsars. GBM provides complementary observations to Swift/BAT, observing many of the same sources, but over a wider energy range.

NuSTAR Hard X-Ray Observation of the Gamma-Ray Binary Candidate HESS J1832-093

NASA Astrophysics Data System (ADS)

Mori, Kaya; Gotthelf, E. V.; Hailey, Charles J.; Hord, Ben J.; de Oña Wilhelmi, Emma; Rahoui, Farid; Tomsick, John A.; Zhang, Shuo; Hong, Jaesub; Garvin, Amani M.; Boggs, Steven E.; Christensen, Finn E.; Craig, William W.; Harrison, Fiona A.; Stern, Daniel; Zhang, William W.

2017-10-01

We present a hard X-ray observation of the TeV gamma-ray binary candidate HESS J1832-093, which is coincident with the supernova remnant G22.7-0.2, using the Nuclear Spectroscopic Telescope Array. Non-thermal X-ray emission from XMMU J183245-0921539, the X-ray source associated with HESS J1832-093, is detected up to ˜30 keV and is well-described by an absorbed power-law model with a best-fit photon index {{Γ }}=1.5+/- 0.1. A re-analysis of archival Chandra and XMM-Newton data finds that the long-term X-ray flux increase of XMMU J183245-0921539 is {50}-20+40 % (90% C.L.), much less than previously reported. A search for a pulsar spin period or binary orbit modulation yields no significant signal to a pulse fraction limit of {f}p< 19 % in the range 4 ms < P< 40 ks. No red noise is detected in the FFT power spectrum to suggest active accretion from a binary system. While further evidence is required, we argue that the X-ray and gamma-ray properties of XMMU J183245-0921539 are most consistent with a non-accreting binary generating synchrotron X-rays from particle acceleration in the shock formed as a result of the pulsar and stellar wind collision. We also report on three nearby hard X-ray sources, one of which may be associated with diffuse emission from a fast-moving supernova fragment interacting with a dense molecular cloud.

Multiwavelength observations of the binary system PSR B1259-63/LS 2883 around the 2010-2011 periastron passage

DOE PAGES

Chernyakova, M.; Abdo, A. A.; Neronov, A.; ...

2014-01-30

Here, we report on broad multiwavelength observations of the 2010–2011 periastron passage of the γ-ray loud binary system PSR B1259-63. High-resolution interferometric radio observations establish extended radio emission trailing the position of the pulsar. Observations with the FermiGamma-ray Space Telescope reveal GeV γ-ray flaring activity of the system, reaching the spin-down luminosity of the pulsar, around 30 d after periastron. Furthermore, there are no clear signatures of variability at radio, X-ray and TeV energies at the time of the GeV flare. Variability around periastron in the Hα emission line, can be interpreted as the gravitational interaction between the pulsar andmore » the circumstellar disc. The equivalent width of the Hα grows from a few days before periastron until a few days later, and decreases again between 18 and 46 d after periastron. In near-infrared we observe the similar decrease of the equivalent width of Brγ line between the 40th and 117th day after the periastron. For the idealized disc, the variability of the Hα line represents the variability of the mass and size of the disc. Finally, we discuss possible physical relations between the state of the disc and GeV emission under assumption that GeV flare is directly related to the decrease of the disc size.« less

Fermi Gamma-Ray Space Telescope: Highlights of the GeV Sky

NASA Technical Reports Server (NTRS)

Thomspon, D. J.

2011-01-01

Because high-energy gamma rays can be produced by processes that also produce neutrinos. the gamma-ray survey of the sky by the Fermi Gamma-ray Space Telescope offers a view of potenl ial targds for neutrino observations. Gamma-ray bursts. active galactic nuclei, and supernova remnants are all sites where hadronic, neutrino-producing interactions are plausible. Pulsars, pulsar wind nebulae, and binary sources are all phenomena that reveal leptonic particle acceleration through their gamma-ray emission. \\Vhile important to gamma-ray astrophysics. such sources are of less interest to neutrino studies. This talk will present a broad overview of the constantly changing sky seen with the Large Area Telescope (LAT) on the Fermi spacecraft.

Acceleration by pulsar winds in binary systems

NASA Technical Reports Server (NTRS)

Harding, Alice K.; Gaisser, T. K.

1990-01-01

In the absence of accretion torques, a pulsar in a binary system will spin down due to electromagnetic dipole radiation and the spin-down power will drive a wind of relativistic electron-positron pairs. Winds from pulsars with short periods will prevent any subsequent accretion but may be confined by the companion star atmosphere, wind, or magnetosphere to form a standing shock. The authors investigate the possibility of particle acceleration at such a pulsar wind shock and the production of very high energy (VHE) and ultra high energy (UHE) gamma rays from interactions of accelerated protons in the companion star's wind or atmosphere. They find that in close binaries containing active pulsars, protons will be shock accelerated to a maximum energy dependent on the pulsar spin-down luminosity. If a significant fraction of the spin-down power goes into particle acceleration, these systems should be sources of VHE and possibly UHE gamma rays. The authors discuss the application of the pulsar wind model to binary sources such as Cygnus X-3, as well as the possibility of observing VHE gamma-rays from known binary radio pulsar systems.

High-entropy fireballs and jets in gamma-ray burst sources

NASA Technical Reports Server (NTRS)

Meszaros, P.; Rees, M. J.

1992-01-01

Two mechanisms whereby compact coalescing binaries can produce relatively 'clean' fireballs via neutrino-antineutrino annihilation are proposed. Preejected mass due to tidal heating will collimate the fireball into jets. The resulting anisotropic gamma-ray emission can be efficient and intense enough to provide an acceptable model for gamma-ray bursts, if these originate at cosmological distances.

TeV Gamma-Ray Observations of the Binary Neutron Star Merger GW170817 with H.E.S.S.

NASA Astrophysics Data System (ADS)

Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Angüner, E. O.; Arakawa, M.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bonnefoy, S.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Büchele, M.; Bulik, T.; Capasso, M.; Caroff, S.; Carosi, A.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Colafrancesco, S.; Condon, B.; Conrad, J.; Davids, I. D.; Decock, J.; Deil, C.; Devin, J.; deWilt, P.; Dirson, L.; Djannati-Ataï, A.; Donath, A.; O'C. Drury, L.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Emery, G.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Funk, S.; Füssling, M.; Gabici, S.; Gallant, Y. A.; Garrigoux, T.; Gaté, F.; Giavitto, G.; Giebels, B.; Glawion, D.; Glicenstein, J. F.; Gottschall, D.; Grondin, M.-H.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holch, T. L.; Holler, M.; Horns, D.; Ivascenko, A.; Iwasaki, H.; Jacholkowska, A.; Jamrozy, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katsuragawa, M.; Katz, U.; Kerszberg, D.; Khangulyan, D.; Khélifi, B.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Malyshev, D.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; Nakashima, S.; de Naurois, M.; Ndiyavala, H.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poireau, V.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Rauth, R.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Rinchiuso, L.; Romoli, C.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Saito, S.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seglar-Arroyo, M.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Shiningayamwe, K.; Simoni, R.; Sol, H.; Spanier, F.; Spir-Jacob, M.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Steppa, C.; Sushch, I.; Takahashi, T.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tsirou, M.; Tsuji, N.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zaborov, D.; Zacharias, M.; Zanin, R.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Zorn, J.; Zywucka, N.; H. E. S. S. Collaboration

2017-12-01

We search for high-energy gamma-ray emission from the binary neutron star merger GW170817 with the H.E.S.S. Imaging Air Cherenkov Telescopes. The observations presented here have been obtained starting only 5.3 hr after GW170817. The H.E.S.S. target selection identified regions of high probability to find a counterpart of the gravitational-wave event. The first of these regions contained the counterpart SSS17a that has been identified in the optical range several hours after our observations. We can therefore present the first data obtained by a ground-based pointing instrument on this object. A subsequent monitoring campaign with the H.E.S.S. telescopes extended over several days, covering timescales from 0.22 to 5.2 days and energy ranges between 270 {GeV} to 8.55 {TeV}. No significant gamma-ray emission has been found. The derived upper limits on the very-high-energy gamma-ray flux for the first time constrain non-thermal, high-energy emission following the merger of a confirmed binary neutron star system.

Ultra high energy gamma rays, cosmic rays and neutrinos from accreting degenerate stars

NASA Technical Reports Server (NTRS)

Brecher, K.; Chanmugam, G.

1985-01-01

Super-Eddington accretion for a recently proposed unipolar induction model of cosmic ray acceleration in accreting binary star systems containing magnetic white dwarfs or neutron stars is considered. For sufficiently high accretion rates and low magnetic fields, the model can account for: (1) acceleration of cosmic ray nuclei up to energies of 10 to the 19th power eV; (2) production of more or less normal solar cosmic ray composition; (3) the bulk of cosmic rays observed with energies above 1 TeV, and probably even down to somewhat lower energies as well; and (4) possibly the observed antiproton cosmic ray flux. It can also account for the high ultra high energy (UHE) gamma ray flux observed from several accreting binary systems (including Cygnus X-3), while allowing the possibility of an even higher neutrino flux from these sources, with L sub nu/L sub gamma is approximately 100.

Enhanced high-energy gamma-ray emission from the microquasar Cygnus X-3 detected by Fermi/LAT

NASA Astrophysics Data System (ADS)

Loh, Alan; Corbel, Stephane

2017-02-01

Following the recent decrease of the hard X-ray emission from the high-mass X-ray binary Cygnus X-3 as seen by the Swift/Burst Alert Telescope (https://swift.gsfc.nasa.gov/results/transients/CygX-3/), the Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed significant gamma-ray emission originating from the microquasar.

Hour time-scale QPOs in the X-ray and radio emission of LS I +61°303

NASA Astrophysics Data System (ADS)

Nösel, S.; Sharma, R.; Massi, M.; Cimò, G.; Chernyakova, M.

2018-05-01

LS I +61°303 is an X-ray binary with a radio outburst every ˜27 d. Previous studies of the stellar system revealed radio microflares superimposed on the large radio outburst. We present here new radio observations of LS I +61°303 at 2.2 GHz with the Westerbork Synthesis Radio Telescope (WSRT). Using various timing analysis methods, we find significant quasi-periodic oscillations (QPOs) of 55 min stable over the duration of 4 d. We also use archival data obtained from the Suzaku satellite at X-ray wavelengths. We report here for the first time significant X-ray QPOs of about 2 h present over the time span of 21 h. We compare our results with the previously reported QPO observations and we conclude that the QPOs seem to be associated with the radio outburst, independent of the amplitude of the outburst. Finally, the different QPO time-scales are discussed in the context of magnetic reconnection.

Observational constraints on the inter-binary stellar flare hypothesis for the gamma-ray bursts

NASA Astrophysics Data System (ADS)

Rao, A. R.; Vahia, M. N.

1994-01-01

The Gamma Ray Observatory/Burst and Transient Source Experiment (GRO/BATSE) results on the Gamma Ray Bursts (GRBs) have given an internally consistent set of observations of about 260 GRBs which have been released for analysis by the BATSE team. Using this database we investigate our earlier suggestion (Vahia and Rao, 1988) that GRBs are inter-binary stellar flares from a group of objects classified as Magnetically Active Stellar Systems (MASS) which includes flare stars, RS CVn binaries and cataclysmic variables. We show that there exists an observationally consistent parameter space for the number density, scale height and flare luminosity of MASS which explains the complete log(N) - log(P) distribution of GRBs as also the observed isotropic distribution. We further use this model to predict anisotropy in the GRB distribution at intermediate luminosities. We make definite predictions under the stellar flare hypothesis that can be tested in the near future.

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.

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.

Binary millisecond pulsar discovery via gamma-ray pulsations.

PubMed

Pletsch, H J; Guillemot, L; Fehrmann, H; Allen, B; Kramer, M; Aulbert, C; Ackermann, M; Ajello, M; de Angelis, A; Atwood, W B; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Borgland, A W; Bottacini, E; Brandt, T J; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Casandjian, J M; Cecchi, C; Çelik, Ö; Charles, E; Chaves, R C G; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cutini, S; D'Ammando, F; Dermer, C D; Digel, S W; Drell, P S; Drlica-Wagner, A; Dubois, R; Dumora, D; Favuzzi, C; Ferrara, E C; Franckowiak, A; Fukazawa, Y; Fusco, P; Gargano, F; Gehrels, N; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guiriec, S; Hadasch, D; Hanabata, Y; Harding, A K; den Hartog, P R; Hayashida, M; Hays, E; Hill, A B; Hou, X; Hughes, R E; Jóhannesson, G; Jackson, M S; Jogler, T; Johnson, A S; Johnson, W N; Kataoka, J; Kerr, M; Knödlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Massaro, F; Mayer, M; Mazziotta, M N; McEnery, J E; Mehault, J; Michelson, P F; Mitthumsiri, W; Mizuno, T; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Nemmen, R; Nuss, E; Ohno, M; Ohsugi, T; Omodei, N; Orienti, M; Orlando, E; de Palma, F; Paneque, D; Perkins, J S; Piron, F; Pivato, G; Porter, T A; Rainò, S; Rando, R; Ray, P S; Razzano, M; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Romani, R W; Romoli, C; Sanchez, D A; Saz Parkinson, P M; Schulz, A; Sgrò, C; do Couto e Silva, E; Siskind, E J; Smith, D A; Spandre, G; Spinelli, P; Suson, D J; Takahashi, H; Tanaka, T; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Tinivella, M; Troja, E; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Waite, A P; Winer, B L; Wood, K S; Wood, M; Yang, Z; Zimmer, S

2012-12-07

Millisecond pulsars, old neutron stars spun up by accreting matter from a companion star, can reach high rotation rates of hundreds of revolutions per second. Until now, all such "recycled" rotation-powered pulsars have been detected by their spin-modulated radio emission. In a computing-intensive blind search of gamma-ray data from the Fermi Large Area Telescope (with partial constraints from optical data), we detected a 2.5-millisecond pulsar, PSR J1311-3430. This unambiguously explains a formerly unidentified gamma-ray source that had been a decade-long enigma, confirming previous conjectures. The pulsar is in a circular orbit with an orbital period of only 93 minutes, the shortest of any spin-powered pulsar binary ever found.

On the possible gamma-ray burst-gravitational wave association in GW150914

NASA Astrophysics Data System (ADS)

Janiuk, Agnieszka; Bejger, M.; Charzyński, S.; Sukova, P.

2017-02-01

Data from the Fermi Gamma-ray Burst Monitor satellite observatory suggested that the recently discovered gravitational wave source, a pair of two coalescing black holes, was related to a gamma-ray burst. The observed high-energy electromagnetic radiation (above 50 keV) originated from a weak transient source and lasted for about 1 s. Its localization is consistent with the direction to GW150914. We speculate about the possible scenario for the formation of a gamma-ray burst accompanied by the gravitational-wave signal. Our model invokes a tight binary system consisting of a massive star and a black hole which leads to the triggering of a collapse of the star's nucleus, the formation of a second black hole, and finally to the binary black hole merger. For the most-likely configuration of the binary spin vectors with respect to the orbital angular momentum in the GW150914 event, the recoil speed (kick velocity) acquired by the final black hole through gravitational wave emission is of the order of a few hundred km/s and this might be sufficient to get it closer to the envelope of surrounding material and capture a small fraction of matter from the remnant of the host star. The gamma-ray burst is produced by the accretion of this remnant matter onto the final black hole. The moderate spin of the final black hole suggests that the gamma-ray burst jet is powered by weak neutrino emission rather than the Blandford-Znajek mechanism, and hence explains the low power available for the observed GRB signal.

TeV Gamma-Ray Observations of the Binary Neutron Star Merger GW170817 with H.E.S.S.

DOE PAGES

Abdalla, H.; Abramowski, A.; Aharonian, F.; ...

2017-11-22

Here, we search for high-energy gamma-ray emission from the binary neutron star merger GW170817 with the H.E.S.S. Imaging Air Cherenkov Telescopes. The observations presented here have been obtained starting only 5.3 hr after GW170817. The H.E.S.S. target selection identified regions of high probability to find a counterpart of the gravitational-wave event. The first of these regions contained the counterpart SSS17a that has been identified in the optical range several hours after our observations. We can therefore present the first data obtained by a ground-based pointing instrument on this object. A subsequent monitoring campaign with the H.E.S.S. telescopes extended over several days, covering timescales from 0.22 to 5.2 days and energy ranges betweenmore » $$270\\,\\mathrm{GeV}$$ to $$8.55\\,\\mathrm{TeV}$$. No significant gamma-ray emission has been found. The derived upper limits on the very-high-energy gamma-ray flux for the first time constrain non-thermal, high-energy emission following the merger of a confirmed binary neutron star system.« less

TeV Gamma-Ray Observations of the Binary Neutron Star Merger GW170817 with H.E.S.S.

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

Abdalla, H.; Abramowski, A.; Aharonian, F.

Here, we search for high-energy gamma-ray emission from the binary neutron star merger GW170817 with the H.E.S.S. Imaging Air Cherenkov Telescopes. The observations presented here have been obtained starting only 5.3 hr after GW170817. The H.E.S.S. target selection identified regions of high probability to find a counterpart of the gravitational-wave event. The first of these regions contained the counterpart SSS17a that has been identified in the optical range several hours after our observations. We can therefore present the first data obtained by a ground-based pointing instrument on this object. A subsequent monitoring campaign with the H.E.S.S. telescopes extended over several days, covering timescales from 0.22 to 5.2 days and energy ranges betweenmore » $$270\\,\\mathrm{GeV}$$ to $$8.55\\,\\mathrm{TeV}$$. No significant gamma-ray emission has been found. The derived upper limits on the very-high-energy gamma-ray flux for the first time constrain non-thermal, high-energy emission following the merger of a confirmed binary neutron star system.« less

Light curve and SED modeling of the gamma-ray binary 1FGL J1018.6–5856: Constraints on the orbital geometry and relativistic flow

DOE PAGES

An, Hongjun; Romani, Roger W.

2017-04-04

We present broadband spectral energy distributions and light curves of the gamma-ray binary 1FGL J1018.6–5856 measured in the X-ray and the gamma-ray bands. We find that the orbital modulation in the low-energy gamma-ray band is similar to that in the X-ray band, suggesting a common spectral component. However, above a GeV the orbital light curve changes significantly. We suggest that the GeV band contains significant flux from a pulsar magnetosphere, while the X-ray to TeV light curves are dominated by synchrotron and Compton emission from an intrabinary shock (IBS). We find that a simple one-zone model is inadequate to explainmore » the IBS emission, but that beamed Synchrotron-self Compton radiation from adiabatically accelerated plasma in the shocked pulsar wind can reproduce the complex multiband light curves, including the variable X-ray spike coincident with the gamma-ray maximum. Furthermore, the model requires an inclination of ~50° and an orbital eccentricity of ~0.35, consistent with the limited constraints from existing optical observations. This picture motivates searches for pulsations from the energetic young pulsar powering the wind shock.« less

Light curve and SED modeling of the gamma-ray binary 1FGL J1018.6–5856: Constraints on the orbital geometry and relativistic flow

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

An, Hongjun; Romani, Roger W.

We present broadband spectral energy distributions and light curves of the gamma-ray binary 1FGL J1018.6–5856 measured in the X-ray and the gamma-ray bands. We find that the orbital modulation in the low-energy gamma-ray band is similar to that in the X-ray band, suggesting a common spectral component. However, above a GeV the orbital light curve changes significantly. We suggest that the GeV band contains significant flux from a pulsar magnetosphere, while the X-ray to TeV light curves are dominated by synchrotron and Compton emission from an intrabinary shock (IBS). We find that a simple one-zone model is inadequate to explainmore » the IBS emission, but that beamed Synchrotron-self Compton radiation from adiabatically accelerated plasma in the shocked pulsar wind can reproduce the complex multiband light curves, including the variable X-ray spike coincident with the gamma-ray maximum. Furthermore, the model requires an inclination of ~50° and an orbital eccentricity of ~0.35, consistent with the limited constraints from existing optical observations. This picture motivates searches for pulsations from the energetic young pulsar powering the wind shock.« less

Light Curve and SED Modeling of the Gamma-Ray Binary 1FGL J1018.6–5856: Constraints on the Orbital Geometry and Relativistic Flow

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

An, Hongjun; Romani, Roger W., E-mail: hjan@chungbuk.ac.kr

We present broadband spectral energy distributions and light curves of the gamma-ray binary 1FGL J1018.6−5856 measured in the X-ray and the gamma-ray bands. We find that the orbital modulation in the low-energy gamma-ray band is similar to that in the X-ray band, suggesting a common spectral component. However, above a GeV the orbital light curve changes significantly. We suggest that the GeV band contains significant flux from a pulsar magnetosphere, while the X-ray to TeV light curves are dominated by synchrotron and Compton emission from an intrabinary shock (IBS). We find that a simple one-zone model is inadequate to explainmore » the IBS emission, but that beamed Synchrotron-self Compton radiation from adiabatically accelerated plasma in the shocked pulsar wind can reproduce the complex multiband light curves, including the variable X-ray spike coincident with the gamma-ray maximum. The model requires an inclination of ∼50° and an orbital eccentricity of ∼0.35, consistent with the limited constraints from existing optical observations. This picture motivates searches for pulsations from the energetic young pulsar powering the wind shock.« less

The Orbit of the Gamma-Ray Binary 1FGL J1018.6−5856

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

Monageng, I. M.; McBride, V. A.; Kniazev, A. Y.

2017-09-20

Gamma-ray binaries are a small subclass of the high mass X-ray binary population that exhibit emission across the whole electromagnetic spectrum. We present the radial velocities of 1FGL J1018.6−5856 based on the observations obtained with the Southern African Large Telescope. We combine our measurements with those published in the literature to get a broad phase coverage. The mass function obtained supports a neutron star compact object, although a black hole mass is possible for the very low inclination angles. The improved phase coverage allows constraints to be placed on the orbital eccentricity ( e = 0.31 ± 0.16), which agreesmore » with the estimates from the high-energy data.« less

Multiwavelength Challenges in the Fermi Era

NASA Technical Reports Server (NTRS)

Thompson, D. J.

2010-01-01

The gamma-ray surveys of the sky by AGILE and the Fermi Gamma-ray Space Telescope offer both opportunities and challenges for multiwavelength and multi-messenger studies. Gamma-ray bursts, pulsars, binary sources, flaring Active Galactic Nuclei, and Galactic transient sources are all phenomena that can best be studied with a wide variety of instruments simultaneously or contemporaneously. From the gamma-ray side, a principal challenge is the latency from the time of an astrophysical event to the recognition of this event in the data. Obtaining quick and complete multiwavelength coverage of gamma-ray sources of interest can be difficult both in terms of logistics and in terms of generating scientific interest.

Evidence for a massive stellar black hole in x ray Nova Muscae

NASA Technical Reports Server (NTRS)

Chen, Wan; Gehrels, Neil; Cheng, F. H.

1992-01-01

We present evidence that the X-ray Nova Muscae system contains a massive, greater than 10 M solarmass, black hole. A recently measured photometric binary mass function gives the black hole mass for this system as a function of orbital inclination angle. From the spectral redshift and width of the positron annihilation gamma-ray line observed by GRANAT/SIGMA, we find the accretion disk inclination angle to be 22 deg plus or minus 18 deg. Assuming the accretion disk lies in the orbital plane of the system, the black hole mass is found to have a lower limit of 14 M solar mass although statistics are poor. This is supported by spectral modeling of combined optical/UV/x-ray/gamma-ray data and by a new Nova Muscae distance limit we derive of greater than 3 kpc. The large mass for this black hole and the high binary mass ratio it implies (greater than 20) raise a serious challenge to theoretical models of the formation and evolution of massive binaries. The gamma-ray line technique introduced here can give tight constraints on orbital parameters when high-sensitivity line measurements are made by such missions as GRO.

High-energy variability of the Pulsar binary PSR J1311-3430

NASA Astrophysics Data System (ADS)

An, Hongjun; Fermi-LAT Collaboration

2018-01-01

We present analysis results of high-energy observations of the extreme mass-ratio black-widow millisecond pulsar binary PSR J1311-3430. Our studies in the UV, X-ray, and gamma-ray bands confirm the orbital modulation in the gamma-ray band as suggested previously. In addition, we find that the modulation is stronger in the high-energy band. In the lower-energy UV and X-ray bands, we detect flares which were observed previously and attributed to magnetic activities. We find that the optical flares are associated with the X-ray flares, suggesting common origin. We explore possible connections of the variabilities with the intrabinary shock (IBS) and magnetic activity on the low mass companion.

NASA Goddard Space Flight Center, on Behalf of the Fermi Large Area Telescope Collaboration

NASA Technical Reports Server (NTRS)

Thompson, David J.

2010-01-01

Because high-energy gamma rays can be produced by processes that also produce neutrinos, the gamma-ray survey of the sky by the Fermi (Gamma-ray Space Telescope offers a view of potential targets for neutrino observations. Gamma-ray bursts. Active Galactic Nuclei, and supernova remnants are all sites where hadronic, neutrino-producing interactions are plausible. Pulsars, pulsar wind nebulae, and binary sources are all phenomena that reveal leptonic particle acceleration through their gamma-ray emission. While important to gamma-ray astrophysics, such sources are of less interest to neutrino studies. This talk will present a broad overview of the constantly changing sky seen with the Large Area Telescope (LAT)on the Fermi spacecraft.

Low mass X-ray binaries in the Inner Galaxy: implications for millisecond pulsars and the GeV excess

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

Haggard, Daryl; Heinke, Craig; Hooper, Dan

2017-05-01

If millisecond pulsars (MSPs) are responsible for the excess gamma-ray emission observed from the region surrounding the Galactic Center, the same region should also contain a large population of low-mass X-ray binaries (LMXBs). In this study, we compile and utilize a sizable catalog of LMXBs observed in the the Milky Way's globular cluster system and in the Inner Galaxy, as well as the gamma-ray emission observed from globular clusters, to estimate the flux of gamma rays predicted from MSPs in the Inner Galaxy. From this comparison, we conclude that only up to ∼ 4-23% of the observed gamma-ray excess ismore » likely to originate from MSPs. This result is consistent with, and more robust than, previous estimates which utilized smaller samples of both globular clusters and LMXBs. If MSPs had been responsible for the entirety of the observed excess, INTEGRAL should have detected ∼ 10{sup 3} LMXBs from within a 10{sup o} radius around the Galactic Center, whereas only 42 LMXBs (and 46 additional LMXB candidates) have been observed.« less

Low mass X-ray binaries in the Inner Galaxy: implications for millisecond pulsars and the GeV excess

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

Haggard, Daryl; Heinke, Craig; Hooper, Dan

2017-05-01

If millisecond pulsars (MSPs) are responsible for the excess gamma-ray emission observed from the region surrounding the Galactic Center, the same region should also contain a large population of low-mass X-ray binaries (LMXBs). In this study, we compile and utilize a sizable catalog of LMXBs observed in the the Milky Way's globular cluster system and in the Inner Galaxy, as well as the gamma-ray emission observed from globular clusters, to estimate the flux of gamma rays predicted from MSPs in the Inner Galaxy. From this comparison, we conclude that only up tomore » $$\\sim$$4-23% of the observed gamma-ray excess is likely to originate from MSPs. This result is consistent with, and more robust than, previous estimates which utilized smaller samples of both globular clusters and LMXBs. If MSPs had been responsible for the entirety of the observed excess, INTEGRAL should have detected $$\\sim$$10^3$ LMXBs from within a $$10^{\\circ}$$ radius around the Galactic Center, whereas only 42 LMXBs (and 46 additional LMXB candidates) have been observed.« less

Very high energy gamma-ray binary stars.

PubMed

Lamb, R C; Weekes, T C

1987-12-11

One of the major astronomical discoveries of the last two decades was the detection of luminous x-ray binary star systems in which gravitational energy from accretion is released by the emission of x-ray photons, which have energies in the range of 0.1 to 10 kiloelectron volts. Recent observations have shown that some of these binary sources also emit photons in the energy range of 10(12) electron volts and above. Such sources contain a rotating neutron star that is accreting matter from a companion. Techniques to detect such radiation are ground-based, simple, and inexpensive. Four binary sources (Hercules X-1, 4U0115+63, Vela X-1, and Cygnus X-3) have been observed by at least two independent groups. Although the discovery of such very high energy "gamma-ray binaries" was not theoretically anticipated, models have now been proposed that attempt to explain the behavior of one or more of the sources. The implications of these observations is that a significant portion of the more energetic cosmic rays observed on Earth may arise from the action of similar sources within the galaxy during the past few million years.

Gamma Rays at Very High Energies

NASA Astrophysics Data System (ADS)

Aharonian, Felix

This chapter presents the elaborated lecture notes on Gamma Rays at Very High Energies given by Felix Aharonian at the 40th Saas-Fee Advanced Course on "Astrophysics at Very High Energies". Any coherent description and interpretation of phenomena related to gammarays requires deep knowledge of many disciplines of physics like nuclear and particle physics, quantum and classical electrodynamics, special and general relativity, plasma physics, magnetohydrodynamics, etc. After giving an introduction to gamma-ray astronomy the author discusses the astrophysical potential of ground-based detectors, radiation mechanisms, supernova remnants and origin of the galactic cosmic rays, TeV emission of young supernova remnants, gamma-emission from the Galactic center, pulsars, pulsar winds, pulsar wind nebulae, and gamma-ray loud binaries.

Long-Term Monitoring Of The High-Energy γ-Ray Emission From Ls I +61°303 And Ls 5039

DOE PAGES

Hadasch, D.; Torres, D. F.; Tanaka, T.; ...

2012-03-22

The Fermi Large Area Telescope (LAT) reported the first definitive GeV detections of the binaries LS I +61°303 and LS 5039 in the first year after its launch in 2008 June. These detections were unambiguous as a consequence of the reduced positional uncertainty and the detection of modulated γ-ray emission on the corresponding orbital periods. An analysis of new data from the LAT, comprising 30 months of observations, identifies a change in the γ-ray behavior of LS I +61°303. An increase in flux is detected in 2009 March and a steady decline in the orbital flux modulation is observed. Significantmore » emission up to 30 GeV is detected by the LAT; prior data sets led to upper limits only. Contemporaneous TeV observations no longer detected the source, or found it—in one orbit—close to periastron, far from the phases at which the source previously appeared at TeV energies. The detailed numerical simulations and models that exist within the literature do not predict or explain many of these features now observed at GeV and TeV energies. New ideas and models are needed to fully explain and understand this behavior. A detailed phase-resolved analysis of the spectral characterization of LS I +61°303 in the GeV regime ascribes a power law with an exponential cutoff spectrum along each analyzed portion of the system's orbit. The on-source exposure of LS 5039 is also substantially increased with respect to our prior publication. In this case, whereas the general γ-ray properties remain consistent, the increased statistics of the current data set allows for a deeper investigation of its orbital and spectral evolution.« less

Fermi Establishes Classical Novae as a Distinct Class of Gamma-ray Sources

NASA Technical Reports Server (NTRS)

Ackermann, M.; Ajello, M.; Albert, A.; Baldini, L.; Ballet, J.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.;

Prospects for joint observations of gravitational waves and gamma rays from merging neutron star binaries

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

Patricelli, B.; Razzano, M.; Fidecaro, F.

The detection of the events GW150914 and GW151226, both consistent with the merger of a binary black hole system (BBH), opened the era of gravitational wave (GW) astronomy. Besides BBHs, the most promising GW sources are the coalescences of binary systems formed by two neutron stars or a neutron star and a black hole. These mergers are thought to be connected with short Gamma Ray Bursts (GRBs), therefore combined observations of GW and electromagnetic (EM) signals could definitively probe this association. We present a detailed study on the expectations for joint GW and high-energy EM observations of coalescences of binarymore » systems of neutron stars with Advanced Virgo and LIGO and with the Fermi gamma-ray telescope. To this scope, we designed a dedicated Montecarlo simulation pipeline for the multimessenger emission and detection by GW and gamma-ray instruments, considering the evolution of the GW detector sensitivities. We show that the expected rate of joint detection is low during the Advanced Virgo and Advanced LIGO 2016–2017 run; however, as the interferometers approach their final design sensitivities, the rate will increase by ∼ a factor of ten. Future joint observations will help to constrain the association between short GRBs and binary systems and to solve the puzzle of the progenitors of GWs. Comparison of the joint detection rate with the ones predicted in this paper will help to constrain the geometry of the GRB jet.« less

Binary Millisecond Pulsar Discovery via Gamma-Ray Pulsations

DOE PAGES

Pletsch, H. J.; Guillemot, L.; Fehrmann, H.; ...

2012-12-07

We present that millisecond pulsars, old neutron stars spun up by accreting matter from a companion star, can reach high rotation rates of hundreds of revolutions per second. Until now, all such “recycled” rotation-powered pulsars have been detected by their spin-modulated radio emission. In a computing-intensive blind search of gamma-ray data from the Fermi Large Area Telescope (with partial constraints from optical data), we detected a 2.5-millisecond pulsar, PSR J1311-3430. This unambiguously explains a formerly unidentified gamma-ray source that had been a decade-long enigma, confirming previous conjectures. Lastly, the pulsar is in a circular orbit with an orbital period ofmore » only 93 minutes, the shortest of any spin-powered pulsar binary ever found.« less

The Firework of Electromagnetic Counterparts from GW170817

NASA Astrophysics Data System (ADS)

Siegel, Daniel

2018-01-01

The gravitational-wave signal of the binary neutron star merger GW170817 was followed by a firework of electromagnetic transients across the entire electromagnetic spectrum. The gamma-ray emission has provided strong evidence for the association of short gamma-ray bursts (SGRBs) with binary neutron star mergers and the ultraviolet, optical, and near-infrared emission is consistent with a kilonova indicative of the formation of heavy elements in the merger ejecta by the rapid neutron capture process (r-process). In this talk, I will discuss and review theoretical scenarios to interpret the gamma-ray, X-ray, and radio observations. I will present recent results from general-relativistic magnetohydrodynamic simulations and discuss possible scenarios and mass ejection mechanisms that can give rise to the observed kilonova features. In particular, I will argue that massive winds from neutrino-cooled post-merger accretion disks most likely synthesized the heavy r-process elements in GW170817.

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.

STELLAR ENCOUNTER RATE IN GALACTIC GLOBULAR CLUSTERS

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

Bahramian, Arash; Heinke, Craig O.; Sivakoff, Gregory R.

2013-04-01

The high stellar densities in the cores of globular clusters cause significant stellar interactions. These stellar interactions can produce close binary mass-transferring systems involving compact objects and their progeny, such as X-ray binaries and radio millisecond pulsars. Comparing the numbers of these systems and interaction rates in different clusters drives our understanding of how cluster parameters affect the production of close binaries. In this paper we estimate stellar encounter rates ({Gamma}) for 124 Galactic globular clusters based on observational data as opposed to the methods previously employed, which assumed 'King-model' profiles for all clusters. By deprojecting cluster surface brightness profilesmore » to estimate luminosity density profiles, we treat 'King-model' and 'core-collapsed' clusters in the same way. In addition, we use Monte Carlo simulations to investigate the effects of uncertainties in various observational parameters (distance, reddening, surface brightness) on {Gamma}, producing the first catalog of globular cluster stellar encounter rates with estimated errors. Comparing our results with published observations of likely products of stellar interactions (numbers of X-ray binaries, numbers of radio millisecond pulsars, and {gamma}-ray luminosity) we find both clear correlations and some differences with published results.« less

HIGH-ENERGY OBSERVATIONS OF PSR B1259–63/LS 2883 THROUGH THE 2014 PERIASTRON PASSAGE: CONNECTING X-RAYS TO THE GeV FLARE

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

Tam, P. H. T.; Li, K. L.; Kong, A. K. H.

2015-01-01

The binary system PSR B1259–63/LS 2883 is well sampled in radio, X-rays, and TeV γ-rays, and shows orbital-phase-dependent variability in these frequencies. The first detection of GeV γ-rays from the system was made around the 2010 periastron passage. In this Letter, we present an analysis of X-ray and γ-ray data obtained by the Swift/XRT, NuSTAR/FPM, and Fermi/LAT, through the recent periastron passage which occurred on 2014 May 4. While PSR B1259–63/LS 2883 was not detected by the Large Area Telescope before and during this passage, we show that the GeV flares occurred at a similar orbital phase as in earlymore » 2011, thus establishing the repetitive nature of the post-periastron GeV flares. Multiple flares each lasting for a few days have been observed and short-term variability is seen as well. We also found X-ray flux variation contemporaneous with the GeV flare for the first time. Strong evidence of the keV-to-GeV connection came from the broadband high-energy spectra, which we interpret as synchrotron radiation from the shocked pulsar wind.« less

Probing the X-ray Emission from the Massive Star Cluster Westerlund 2

NASA Astrophysics Data System (ADS)

Lopez, Laura

2017-09-01

We propose a 300 ks Chandra ACIS-I observation of the massive star cluster Westerlund 2 (Wd2). This region is teeming with high-energy emission from a variety of sources: colliding wind binaries, OB and Wolf-Rayet stars, two young pulsars, and an unidentified source of very high-energy (VHE) gamma-rays. Our Chandra program is designed to achieve several goals: 1) to take a complete census of Wd2 X-ray point sources and monitor variability; 2) to probe the conditions of the colliding winds in the binary WR 20a; 3) to search for an X-ray counterpart of the VHE gamma-rays; 4) to identify diffuse X-ray emission; 5) to compare results to other massive star clusters observed by Chandra. Only Chandra has the spatial resolution and sensitivity necessary for our proposed analyses.

Six New Millisecond Pulsars From Arecibo Searches Of Fermi Gamma-Ray Sources

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

Cromartie, H. T.; Camilo, F.; Kerr, M.

2016-02-25

We have discovered six radio millisecond pulsars (MSPs) in a search with the Arecibo telescope of 34 unidentified gamma-ray sources from the Fermi Large Area Telescope (LAT) 4-year point source catalog. Among the 34 sources, we also detected two MSPs previously discovered elsewhere. Each source was observed at a center frequency of 327 MHz, typically at three epochs with individual integration times of 15 minutes. The new MSP spin periods range from 1.99 to 4.66 ms. Five of the six pulsars are in interacting compact binaries (period ≤ 8.1 hr), while the sixth is a more typical neutron star-white dwarfmore » binary with an 83-day orbital period. This is a higher proportion of interacting binaries than for equivalent Fermi-LAT searches elsewhere. The reason is that Arecibo’s large gain afforded us the opportunity to limit integration times to 15 minutes, which significantly increased our sensitivity to these highly accelerated systems. Seventeen of the remaining 26 gamma-ray sources are still categorized as strong MSP candidates, and will be re-searched.« less

SIX NEW MILLISECOND PULSARS FROM ARECIBO SEARCHES OF FERMI GAMMA-RAY SOURCES

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

Cromartie, H. T.; Camilo, F.; Kerr, M.

2016-03-01

We have discovered six radio millisecond pulsars (MSPs) in a search with the Arecibo telescope of 34 unidentified gamma-ray sources from the Fermi Large Area Telescope (LAT) four year point source catalog. Among the 34 sources, we also detected two MSPs previously discovered elsewhere. Each source was observed at a center frequency of 327 MHz, typically at three epochs with individual integration times of 15 minutes. The new MSP spin periods range from 1.99 to 4.66 ms. Five of the six pulsars are in interacting compact binaries (period ≤ 8.1 hr), while the sixth is a more typical neutron star-whitemore » dwarf binary with an 83 day orbital period. This is a higher proportion of interacting binaries than for equivalent Fermi-LAT searches elsewhere. The reason is that Arecibo's large gain afforded us the opportunity to limit integration times to 15 minutes, which significantly increased our sensitivity to these highly accelerated systems. Seventeen of the remaining 26 gamma-ray sources are still categorized as strong MSP candidates, and will be re-searched.« less

Tidal heating and mass loss in neutron star binaries - Implications for gamma-ray burst models

NASA Technical Reports Server (NTRS)

Meszaros, P.; Rees, M. J.

1992-01-01

A neutron star in a close binary orbit around another neutron star (or stellar-mass black hole) spirals inward owing to gravitational radiation. We discuss the effects of tidal dissipation during this process. Tidal energy dissipated in the neutron star's core escapes mainly as neutrinos, but heating of the crust, and outward diffusion of photons, blows off the outer layers of the star. This photon-driven mass loss precedes the final coalescence. The presence of this eject material impedes the escape of gamma-rays created via neutrino interactions. If an e(+) - e(-) fireball, created in the late stages of coalescence, were loaded with (or surrounded by) material with the mean column density of the ejecta, it could not be an efficient source of gamma-rays. Models for cosmologically distant gamma-rays burst that involve neutron stars must therefore be anisotropic, so that the fireball expands preferentially in directions where the column density of previously blown-off material is far below the spherically averaged value which we have calculated. Some possible 'scenarios' along these lines are briefly discussed.

GeV Detection of HESS J0632+057

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

Li, Jian; Torres, Diego F.; Wilhelmi, Emma de Oña

2017-09-10

HESS J0632+057 is the only gamma-ray binary that has been detected at TeV energies, but not at GeV energies yet. Based on nearly nine years of Fermi Large Area Telescope (LAT) Pass 8 data, we report here on a deep search for the gamma-ray emission from HESS J0632+057 in the 0.1–300 GeV energy range. We find a previously unknown gamma-ray source, Fermi J0632.6+0548, spatially coincident with HESS J0632+057. The measured flux of Fermi J0632.6+0548 is consistent with the previous flux upper limit on HESS J0632+057 and shows variability that can be related to the HESS J0632+057 orbital phase. We proposemore » that Fermi J0632.6+0548 is the GeV counterpart of HESS J0632+057. Considering the Very High Energy spectrum of HESS J0632+057, a possible spectral turnover above 10 GeV may exist in Fermi J0632.6+0548, as appears to be common in other established gamma-ray binaries.« less

A black hole-white dwarf compact binary model for long gamma-ray bursts without supernova association

NASA Astrophysics Data System (ADS)

Dong, Yi-Ze; Gu, Wei-Min; Liu, Tong; Wang, Junfeng

2018-03-01

Gamma-ray bursts (GRBs) are luminous and violent phenomena in the Universe. Traditionally, long GRBs are expected to be produced by the collapse of massive stars and associated with supernovae. However, some low-redshift long GRBs have no detection of supernova association, such as GRBs 060505, 060614, and 111005A. It is hard to classify these events convincingly according to usual classifications, and the lack of the supernova implies a non-massive star origin. We propose a new path to produce long GRBs without supernova association, the unstable and extremely violent accretion in a contact binary system consisting of a stellar-mass black hole and a white dwarf, which fills an important gap in compact binary evolution.

Binary interaction dominates the evolution of massive stars.

PubMed

Sana, H; de Mink, S E; de Koter, A; Langer, N; Evans, C J; Gieles, M; Gosset, E; Izzard, R G; Le Bouquin, J-B; Schneider, F R N

2012-07-27

The presence of a nearby companion alters the evolution of massive stars in binary systems, leading to phenomena such as stellar mergers, x-ray binaries, and gamma-ray bursts. Unambiguous constraints on the fraction of massive stars affected by binary interaction were lacking. We simultaneously measured all relevant binary characteristics in a sample of Galactic massive O stars and quantified the frequency and nature of binary interactions. More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases. These numbers greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations of massive stars and their supernovae.

Gamma rays as probe of fission and quasi-fission dynamics in the reaction 32S + 197Au near the Coulomb barrier

NASA Astrophysics Data System (ADS)

Pulcini, A.; Vardaci, E.; Kozulin, E.; Ashaduzzaman, M.; Borcea, C.; Bracco, A.; Brambilla, S.; Calinescu, S.; Camera, F.; Ciemala, M.; de Canditiis, B.; Dorvaux, O.; Harca, I. M.; Itkis, I.; Kirakosyan, V. V.; Knyazheva, G.; Kozulina, N.; Kolesov, I. V.; La Rana, G.; Maj, A.; Matea, I.; Novikov, K.; Petrone, C.; Quero, D.; Rath, P.; Saveleva, E.; Schmitt, C.; Sposito, G.; Stezowski, O.; Trzaska, W. H.; Wilson, J.

2018-05-01

Compound nucleus fission and quasi-fission are both binary decay channels whose common properties make the experimental separation between them difficult. A way to achieve this separation could be to probe the angular momentum of the binary fragments. This can be done detecting gamma rays in coincidence with the two fragments. As a case study, the reaction 32S + 197Au near the Coulomb barrier has been performed at the Tandem ALTO facility at IPN ORSAY. ORGAM and PARIS, two different gamma detectors arrays, are coupled with the CORSET detector, a two-arm time-of-flight spectrometer. TOF-TOF data were analyzed to reconstruct the mass-energy distribution of the primary fragments coupled with gamma multiplicity and spectroscopic analysis. Preliminary results of will be shown.

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.

Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory

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

Albert, A.; André, M.; Anghinolfi, M.

The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV–EeV energy range using the Antares, IceCube, and Pierre Auger Observatories. No neutrinos directionally coincidentmore » with the source were detected within ±500 s around the merger time. Additionally, no MeV neutrino burst signal was detected coincident with the merger. We further carried out an extended search in the direction of the source for high-energy neutrinos within the 14 day period following the merger, but found no evidence of emission. We used these results to probe dissipation mechanisms in relativistic outflows driven by the binary neutron star merger. The non-detection is consistent with model predictions of short GRBs observed at a large off-axis angle.« less

Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory

DOE PAGES

Albert, A.; André, M.; Anghinolfi, M.; ...

2017-11-29

The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV–EeV energy range using the Antares, IceCube, and Pierre Auger Observatories. No neutrinos directionally coincidentmore » with the source were detected within ±500 s around the merger time. Additionally, no MeV neutrino burst signal was detected coincident with the merger. We further carried out an extended search in the direction of the source for high-energy neutrinos within the 14 day period following the merger, but found no evidence of emission. We used these results to probe dissipation mechanisms in relativistic outflows driven by the binary neutron star merger. The non-detection is consistent with model predictions of short GRBs observed at a large off-axis angle.« less

Search for High-energy Neutrinos from Binary Neutron Star Merger GW170817 with ANTARES, IceCube, and the Pierre Auger Observatory

NASA Astrophysics Data System (ADS)

Albert, A.; André, M.; Anghinolfi, M.; Ardid, M.; Aubert, J.-J.; Aublin, J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Belhorma, B.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M. C.; Brânzaş, H.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Cherkaoui El Moursli, R.; Chiarusi, T.; Circella, M.; Coelho, J. A. B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Díaz, A. F.; Deschamps, A.; De Bonis, G.; Distefano, C.; Di Palma, I.; Domi, A.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; El Khayati, N.; Elsässer, D.; Enzenhöfer, A.; Ettahiri, A.; Fassi, F.; Felis, I.; Fusco, L. A.; Gay, P.; Giordano, V.; Glotin, H.; Grégoire, T.; Ruiz, R. Gracia; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernández-Rey, J. J.; Hößl, J.; Hofestädt, J.; Illuminati, G.; James, C. W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Lotze, M.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J. A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Navas, S.; Nezri, E.; Organokov, M.; Păvălaş, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Sánchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schüssler, F.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Turpin, D.; Tönnis, C.; Vallage, B.; Van Elewyck, V.; Versari, F.; Vivolo, D.; Vizzoca, A.; Wilms, J.; Zornoza, J. D.; Zúñiga, J.; ANTARES Collaboration; Aartsen, M. G.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Samarai, I. Al; Altmann, D.; Andeen, K.; Anderson, T.; Ansseau, I.; Anton, G.; Argüelles, C.; Auffenberg, J.; Axani, S.; Bagherpour, H.; Bai, X.; Barron, J. P.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; BenZvi, S.; Berley, D.; Bernardini, E.; Besson, D. Z.; Binder, G.; Bindig, D.; Blaufuss, E.; Blot, S.; Bohm, C.; Börner, M.; Bos, F.; Bose, D.; Böser, S.; Botner, O.; Bourbeau, E.; Bourbeau, J.; Bradascio, F.; Braun, J.; Brayeur, L.; Brenzke, M.; Bretz, H.-P.; Bron, S.; Brostean-Kaiser, J.; Burgman, A.; Carver, T.; Casey, J.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Clark, K.; Classen, L.; Coenders, S.; Collin, G. H.; Conrad, J. M.; Cowen, D. F.; Cross, R.; Day, M.; de André, J. P. A. M.; De Clercq, C.; DeLaunay, J. J.; Dembinski, H.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; di Lorenzo, V.; Dujmovic, H.; Dumm, J. P.; Dunkman, M.; Dvorak, E.; Eberhardt, B.; Ehrhardt, T.; Eichmann, B.; Eller, P.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Felde, J.; Filimonov, K.; Finley, C.; Flis, S.; Franckowiak, A.; Friedman, E.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Giang, W.; Glauch, T.; Glüsenkamp, T.; Goldschmidt, A.; Gonzalez, J. G.; Grant, D.; Griffith, Z.; Haack, C.; Hallgren, A.; Halzen, F.; Hanson, K.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Hokanson-Fasig, B.; Hoshina, K.; Huang, F.; Huber, M.; Hultqvist, K.; Hünnefeld, M.; In, S.; Ishihara, A.; Jacobi, E.; Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, B. J. P.; Kalaczynski, P.; Kang, W.; Kappes, A.; Karg, T.; Karle, A.; Katz, U.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kheirandish, A.; Kim, J.; Kim, M.; Kintscher, T.; Kiryluk, J.; Kittler, T.; Klein, S. 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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, 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.; 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

2017-12-01

The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV–EeV energy range using the ANTARES, IceCube, and Pierre Auger Observatories. No neutrinos directionally coincident with the source were detected within ±500 s around the merger time. Additionally, no MeV neutrino burst signal was detected coincident with the merger. We further carried out an extended search in the direction of the source for high-energy neutrinos within the 14 day period following the merger, but found no evidence of emission. We used these results to probe dissipation mechanisms in relativistic outflows driven by the binary neutron star merger. The non-detection is consistent with model predictions of short GRBs observed at a large off-axis angle.

Soft X-ray Absorption Edges in LMXBs

NASA Technical Reports Server (NTRS)

2004-01-01

The XMM observation of LMC X-2 is part of our program to study X-ray absorption in the interstellar medium (ISM). This program includes a variety of bright X-ray binaries in the Galaxy as well as the Magellanic Clouds (LMC and SMC). LMC X-2 is located near the heart of the LMC. Its very soft X-ray spectrum is used to determine abundance and ionization fractions of neutral and lowly ionized oxygen of the ISM in the LMC. The RGS spectrum so far allowed us to determine the O-edge value to be for atomic O, the EW of O-I in the ls-2p resonance absorption line, and the same for O-II. The current study is still ongoing in conjunction with other low absorption sources like Sco X-1 and the recently observed X-ray binary 4U 1957+11.

Discovery of an Unidentified Fermi Object as a Black Widow-Like Millisecond Pulsar

NASA Technical Reports Server (NTRS)

Kong, A. K. H.; Huang, R. H. H.; Cheng, K. S.; Takata, J.; Yatsu, Y.; Cheung, C. C.; Donato, D.; Lin, L. C. C.; Kataoka, J.; Takahashi, Y.;

Ground-based very high energy gamma ray astronomy: Observational highlights

NASA Technical Reports Server (NTRS)

Turver, K. E.

1986-01-01

It is now more than 20 years since the first ground based gamma ray experiments involving atmospheric Cerenkov radiation were undertaken. The present highlights in observational ground-based very high energy (VHE) gamma ray astronomy and the optimism about an interesting future for the field follow progress in these areas: (1) the detection at increased levels of confidence of an enlarged number of sources so that at present claims were made for the detection, at the 4 to 5 sd level of significance, of 8 point sources; (2) the replication of the claimed detections with, for the first time, confirmation of the nature and detail of the emission; and (3) the extension of gamma ray astronomy to the ultra high energy (UHE) domain. The pattern, if any, to emerge from the list of sources claimed so far is that X-ray binary sources appear to be copious emitters of gamma rays over at least 4 decades of energy. These X-ray sources which behave as VHE and UHE gamma ray emitters are examined.

Gamma-ray bursts as the death throes of massive binary stars

NASA Technical Reports Server (NTRS)

Narayan, Ramesh; Paczynski, Bohdan; Piran, Tsvi

1992-01-01

We propose that gamma-ray bursts are created in the mergers of double neutron star binaries and black hole neutron star binaries at cosmological distances. Two different processes provide the electromagnetic energy for the bursts: neutrino-antineutrino annihilation into electron-position pairs during the merger, and magnetic flares generated by the Parker instability in a postmerger differentially rotating disk. In both cases, an optically thick fireball of size less than or approximately equal to 100 km is initially created, which expands ultrarelativistically to large radii before radiating. The scenario is only qualitative at this time, but it eliminates many previous objections to the cosmological merger model. The strongest bursts should be found close to, but not at the centers of, galaxies at redshifts of order 0.1, and should be accompanied by bursts of gravitational radiation from the spiraling-in binary which could be detected by LIGO.

Low-mass X-ray binary evolution and the origin of millisecond pulsars

NASA Technical Reports Server (NTRS)

Frank, Juhan; King, Andrew R.; Lasota, Jean-Pierre

1992-01-01

The evolution of low-mass X-ray binaries (LMXBs) is considered. It is shown that X-ray irradiation of the companion stars causes these systems to undergo episodes of rapid mass transfer followed by detached phases. The systems are visible as bright X-ray binaries only for a short part of each cycle, so that their space density must be considerably larger than previously estimated. This removes the difficulty in regarding LMXBs as the progenitors of low-mass binary pulsars. The low-accretion-rate phase of the cycle with the soft X-ray transients is identified. It is shown that 3 hr is likely to be the minimum orbital period for LMXBs with main-sequence companions and it is suggested that the evolutionary endpoint for many LMXBs may be systems which are the sites of gamma-ray bursts.

Six millisecond pulsars detected by the Fermi Large Area Telescope and the radio/gamma-ray connection of millisecond pulsars

DOE PAGES

Espinoza, C. M.; Guillemot, L.; Celik, O.; ...

2013-01-25

In this work, we report on the discovery of gamma-ray pulsations from five millisecond pulsars (MSPs) using the Fermi Large Area Telescope (LAT) and timing ephemerides provided by various radio observatories. We also present confirmation of the gamma-ray pulsations from a sixth source, PSR J2051-0827. Five of these six MSPs are in binary systems: PSRs J1713+0747, J1741+1351, J1600-3053 and the two black widow binary pulsars PSRs J0610-2100 and J2051-0827. The only isolated MSP is the nearby PSR J1024-0719, which is also known to emit X-rays. We present X-ray observations in the direction of PSRs J1600-3053 and J2051-0827. While PSR J2051-0827more » is firmly detected, we can only give upper limits for the X-ray flux of PSR J1600-3053. There are no dedicated X-ray observations available for the other three objects. The MSPs mentioned above, together with most of the MSPs detected by Fermi, are used to put together a sample of 30 gamma-ray MSPs. This sample is used to study the morphology and phase connection of radio and gamma-ray pulse profiles. We show that MSPs with pulsed gamma-ray emission which is phase-aligned with the radio emission present the steepest radio spectra and the largest magnetic fields at the light cylinder among all MSPs. Also, we observe a trend towards very low, or undetectable, radio linear polarization levels. These properties could be attributed to caustic radio emission produced at a range of different altitudes in the magnetosphere. In conclusion, we note that most of these characteristics are also observed in the Crab pulsar, the only other radio pulsar known to exhibit phase-aligned radio and gamma-ray emission.« less

An MS-DOS-based program for analyzing plutonium gamma-ray spectra

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

Ruhter, W.D.; Buckley, W.M.

1989-09-07

A plutonium gamma-ray analysis system that operates on MS-DOS-based computers has been developed for the International Atomic Energy Agency (IAEA) to perform in-field analysis of plutonium gamma-ray spectra for plutonium isotopics. The program titled IAEAPU consists of three separate applications: a data-transfer application for transferring spectral data from a CICERO multichannel analyzer to a binary data file, a data-analysis application to analyze plutonium gamma-ray spectra, for plutonium isotopic ratios and weight percents of total plutonium, and a data-quality assurance application to check spectral data for proper data-acquisition setup and performance. Volume 3 contains the software listings for these applications.

Search for gamma-ray emission from AE Aquarii with seven year of Fermi LAT observations

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

Li, Jian; Torres, Diego F.; Rea, Nanda

2016-11-14

AE Aquarii (AE Aqr) is a cataclysmic binary hosting one of the fastest rotating (more » $${P}_{\\mathrm{spin}}$$ = 33.08 s) white dwarfs (WDs) known. Based on seven years of Fermi Large Area Telescope (LAT) Pass 8 data, we report on a deep search for gamma-ray emission from AE Aqr. When using X-ray observations from ASCA, XMM-Newton, Chandra, Swift, Suzaku, and NuSTAR, spanning 20 years, we substantially extend and improve the spin ephemeris of AE Aqr. Using this ephemeris, we searched for gamma-ray pulsations at the spin period of the WD. We detected no gamma-ray pulsations above 3σ significance. Neither phase-averaged gamma-ray emission nor gamma-ray variability of AE Aqr is detected by Fermi LAT. We also impose the most restrictive upper limit to the gamma-ray flux from AE Aqr to date: $$1.3\\times {10}^{-12}$$ erg cm -2 s -1 in the 100 MeV–300 GeV energy range, providing constraints on models.« less

How gravitational-wave observations can shape the gamma-ray burst paradigm

NASA Astrophysics Data System (ADS)

Bartos, I.; Brady, P.; Márka, S.

2013-06-01

By reaching through shrouding blastwaves, efficiently discovering off-axis events and probing the central engine at work, gravitational wave (GW) observations will soon revolutionize the study of gamma-ray bursts. Already, analyses of GW data targeting gamma-ray bursts have helped constrain the central engines of selected events. Advanced GW detectors with significantly improved sensitivities are under construction. After outlining the GW emission mechanisms from gamma-ray burst progenitors (binary coalescences, stellar core collapses, magnetars and others) that may be detectable with advanced detectors, we review how GWs will improve our understanding of gamma-ray burst central engines, their astrophysical formation channels and the prospects and methods for different search strategies. We place special emphasis on multimessenger searches. To achieve the most scientific benefit, GW, electromagnetic and neutrino observations should be combined to provide greater discriminating power and science reach.

A hydrodynamics-informed, radiation model for HESS J0632+057 from radio to gamma rays

NASA Astrophysics Data System (ADS)

Barkov, Maxim V.; Bosch-Ramon, Valenti

2018-06-01

Relativistic hydrodynamical simulations of the eccentric gamma-ray binary HESS J0632+057 show that the energy of a putative pulsar wind should accumulate in the binary surroundings between periastron and apastron, being released by fast advection close to apastron. To assess whether this could lead to a maximum of the non-thermal emission before apastron, we derive simple prescriptions for the non-thermal energy content, the radiation efficiency, and the impact of energy losses on non-thermal particles, in the simulated hydrodynamical flow. These prescriptions are used to estimate the non-thermal emission in radio, X-rays, GeV, and TeV, from the shocked pulsar wind in a binary system simulated using a simplified 3-dimensional scheme for several orbital cycles. Lightcurves at different wavelengths are derived, together with synthetic radio images for different orbital phases. The dominant peak in the computed lightcurves is broad and appears close to, but before, apastron. This peak is followed by a quasi-plateau shape, and a minor peak only in gamma rays right after periastron. The radio maps show ejection of radio blobs before apastron in the periastron-apastron direction. The results show that a scenario with a highly eccentric high-mass binary hosting a young pulsar can explain the general phenomenology of HESS J0632+057: despite its simplicity, the adopted approach yields predictions that are robust at a semi-quantitative level and consistent with multiwavelength observations.

Gamma-rays from the binary system containing PSR J2032+4127 during its periastron passage

NASA Astrophysics Data System (ADS)

Bednarek, Włodek; Banasiński, Piotr; Sitarek, Julian

2018-01-01

The energetic pulsar, PSR J2032+4127, has recently been discovered in the direction of the unidentified HEGRA TeV γ-ray source (TeV J2032+4130). It is proposed that this pulsar forms a binary system with the Be type star, MT91 213, expected to reach periastron late in 2017. We performed detailed calculations of the γ-ray emission produced close to the binary system’s periastron passage by applying a simple geometrical model. Electrons accelerated at the collision region of pulsar and stellar winds initiate anisotropic inverse Compton {e}+/- pair cascades by scattering soft radiation from the massive companion. The γ-ray spectra, from such a comptonization process, are compared with the measurements of the extended TeV γ-ray emission from the HEGRA TeV γ-ray source. We discuss conditions within the binary system, at the periastron passage of the pulsar, for which the γ-ray emission from the binary can overcome the extended, steady TeV γ-ray emission from the HEGRA TeV γ-ray source.

FERMI STUDY OF 5–300 GeV EMISSION FROM THE HIGH-MASS PULSAR BINARY PSR B1259-63/LS 2883

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

Xing, Yi; Wang, Zhongxiang; Takata, Jumpei

2016-09-01

We report the results from our detailed analysis of the Fermi Large Area Telescope data for the pulsar binary PSR B1259−63/LS 2883. During the GeV flares that occurred when the pulsar was in the periastron passages, we have detected a 5–300 GeV component at ≃5 σ in emission from the binary. The detection verifies the presence of the component that has been marginally found in previous studies of the binary. Furthermore, we have discovered that this component was marginally present even in the quiescent state of the binary, specifically the mean anomaly phase 0.7–0.9. The component can be described bymore » a power law with a photon index Γ ∼ 1.4, and the flux in the flares is approximately one order of magnitude higher than that in quiescence. We discuss the origin of this component. It likely arises from the inverse-Compton process: due to the interaction between the winds from the pulsar and its massive companion, high-energy particles from the shock scatter the seed photons from the companion to GeV/TeV energies. Based on this scenario, model fits to the broad-band X-ray to TeV spectra of the binary in the flaring and quiescent states are provided.« less

GBM Observations of Be X-Ray Binary Outbursts

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.; Finger, M. H.; Jenke, P. A.

2014-01-01

Since 2008 we have been monitoring accreting pulsars using the Gamma ray Burst Monitor (GBM) on Fermi. This monitoring program includes daily blind full sky searches for previously unknown or previously quiescent pulsars and source specific analysis to track the frequency evolution of all detected pulsars. To date we have detected outbursts from 23 transient accreting pulsars, including 21 confirmed or likely Be/X-ray binaries. I will describe our techniques and highlight results for selected pulsars.

On the Rate and on the Gravitational Wave Emission of Short and Long GRBs

NASA Astrophysics Data System (ADS)

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

2018-05-01

On the ground of the large number of gamma-ray bursts (GRBs) detected with cosmological redshift, we classified GRBs in seven subclasses, all with binary progenitors which emit gravitational waves (GWs). Each binary is composed of combinations of carbon–oxygen cores (COcore), neutron stars (NSs), black holes (BHs), and white dwarfs (WDs). The long bursts, traditionally assumed to originate from a BH with an ultrarelativistic jetted emission, not emitting GWs, have been subclassified as (I) X-ray flashes (XRFs), (II) binary-driven hypernovae (BdHNe), and (III) BH–supernovae (BH–SNe). They are framed within the induced gravitational collapse paradigm with a progenitor COcore–NS/BH binary. The SN explosion of the COcore triggers an accretion process onto the NS/BH. If the accretion does not lead the NS to its critical mass, an XRF occurs, while when the BH is present or formed by accretion, a BdHN occurs. When the binaries are not disrupted, XRFs lead to NS–NS and BdHNe lead to NS–BH. The short bursts, originating in NS–NS, are subclassified as (IV) short gamma-ray flashes (S-GRFs) and (V) short GRBs (S-GRBs), the latter when a BH is formed. There are (VI) ultrashort GRBs (U-GRBs) and (VII) gamma-ray flashes (GRFs) formed in NS–BH and NS–WD, respectively. We use the occurrence rate and GW emission of these subclasses to assess their detectability by Advanced LIGO-Virgo, eLISA, and resonant bars. We discuss the consequences of our results in view of the announcement of the LIGO/Virgo Collaboration of the source GW 170817 as being originated by an NS–NS.

A NuSTAR Observation of the Gamma-Ray Emitting Millisecond Pulsar PSR J1723–2837

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

Kong, A. K. H.; Hui, C. Y.; Takata, J.

We report on the first NuSTAR observation of the gamma-ray emitting millisecond pulsar binary PSR J1723–2837. X-ray radiation up to 79 keV is clearly detected, and the simultaneous NuSTAR and Swift spectrum is well described by an absorbed power law with a photon index of ∼1.3. We also find X-ray modulations in the 3–10, 10–20, 20–79, and 3–79 keV bands at the 14.8 hr binary orbital period. All of these are entirely consistent with previous X-ray observations below 10 keV. This new hard X-ray observation of PSR J1723–2837 provides strong evidence that the X-rays are from the intrabinary shock viamore » an interaction between the pulsar wind and the outflow from the companion star. We discuss how the NuSTAR observation constrains the physical parameters of the intrabinary shock model.« less

MOXE: An X-ray all-sky monitor for Soviet Spectrum-X-Gamma Mission

NASA Technical Reports Server (NTRS)

Priedhorsky, W.; Fenimore, E. E.; Moss, C. E.; Kelley, R. L.; Holt, S. S.

1989-01-01

A Monitoring Monitoring X-Ray Equipment (MOXE) is being developed for the Soviet Spectrum-X-Gamma Mission. MOXE is an X-ray all-sky monitor based on array of pinhole cameras, to be provided via a collaboration between Goddard Space Flight Center and Los Alamos National Laboratory. The objectives are to alert other observers on Spectrum-X-Gamma and other platforms of interesting transient activity, and to synoptically monitor the X-ray sky and study long-term changes in X-ray binaries. MOXE will be sensitive to sources as faint as 2 milliCrab (5 sigma) in 1 day, and cover the 2 to 20 KeV band.

Three years of Transients with Fermi GBM

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.

2012-01-01

The Gamma-ray Burst Monitor (GBM) is an all-sky monitoring instrument, sensitive between 8 keV and 40 MeV, with a primary objective of supporting the Large Area Telescope (LAT) in observations of Gamma-Ray Bursts (GRBs). Both instruments are part of the Fermi Gamma-ray Space Telescope. Together, the GBM and LAT instruments have provided ground-breaking measurements of GRBs that have, after 10 years of focus on GRB afterglows, inspired renewed interest in the prompt emission phase of GRBs and the physical mechanisms that fuel them. In addition to GRB science, GBM has made significant contributions to the astrophysics of galactic transient sources including long-term variations in the Crab nebula, spin state transitions in accretion powered pulsars, state transitions in black hole X-ray binaries, and unprecedented time-resolved spectral studies of soft gamma-ray repeater bursts. Closer to home, GBM also contributes to solar flare and terrestrial gamma flash science.

Fast transient X-rays and gamma ray bursts - Are they stellar flares?

NASA Astrophysics Data System (ADS)

Rao, A. R.; Vahia, M. N.

Short period transient X-ray emissions (FTX) have been observed from several sources in the sky and the largest single group of objects identified with such sources are active stars: flare stars, and RS CVn binaries. The study of the number, source and flux distribution of the fast transient X-ray sources shows that all the FTX emission can be treated as flares in the interbinary regions of active stars. It is suggested that the FTX emission is a common feature of the gamma ray bursts (GRBs). The evidence for the similarity between the hard X-ray flares and GRBs is discussed, and the possibility that the gamma ray bursts are the impulsive precursors of FTX originating from active stars with large scale magnetic activity is examined.

Sigma observations of the low mass X-ray binaries of the galactic bulge

NASA Technical Reports Server (NTRS)

Goldwurm, A.; Denis, M.; Paul, J.; Faisse, S.; Roques, J. P.; Bouchet, L.; Vedrenne, G.; Mandrou, P.; Sunyaev, R.; Churazov, E.

1995-01-01

The soft gamma-ray telescope (35-1300 keV) SIGMA aboard the high energy GRANAT space observatory has been monitoring the Galactic Bulge region for more than 2000 h of effective time since March 1990. In the resulting average 35-75 keV image we detected ten sources at a level of greater than 5 standard deviations, 6 of which can be identified with low mass X-ray binaries (LMXB). Among them, one is the 1993 X-ray nova in Ophiuchus (GRS 1726-249), one is an X-ray pulsar (GX 1+4), two are associated with X-ray bursters (GX 354-0 and A 1742-294) and two with bursting X-ray binaries in the globular clusters Terzan 2 and Terzan 1. Their spectral and long term variability behavior as measured by SIGMMA are presented and discussed.

Five New Millisecond Pulsars from a Radio Survey of 14 Unidentified Fermi-LAT Gamma-Ray Sources

NASA Technical Reports Server (NTRS)

Kerr, M.; Camilo, F.; Johnson, T. J.; Ferrara, E. C.; Guillemot, L.; Harding, A. K.; Hessels, J.; Johnson, S.; Keith, M.; Kramer, M.;

All-Sky Monitoring with the Fermi Gamma Ray Burst Monitor

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.

2010-01-01

We are currently monitoring the transient hard X-ray/soft gamma ray sky using the Gamma Ray Burst Monitor (GBM) on-board Fermi. The twelve GBM NaI detectors span 8 keV to 1MeV, while the two GBM BGO detectors span about 150 keV to 40 MeV. With GBM, we detect transient events on multiple timescales. Brief events, such as Gamma Ray Bursts, Solar flares, and magnetar bursts are detected with on-board triggers. On longer timescales, we use the Earth occultation technique to monitor a number of sources, including X-ray binaries, AGN, and solar flaring activity. To date we have detected 7 sources above 100 keV. Transient activity from accretion-powered pulsars is monitored using epoch-folding techniques. With GBM we track the pulsed flux and frequency for a number of pulsars. We will present highlights of GBM observations on various timescales.

GRB 111005A at z = 0.0133 and the Prospect of Establishing Long-Short GRB/GW Association

NASA Astrophysics Data System (ADS)

Wang, Yuan-Zhu; Huang, Yong-Jia; Liang, Yun-Feng; Li, Xiang; Jin, Zhi-Ping; Zhang, Fu-Wen; Zou, Yuan-Chuan; Fan, Yi-Zhong; Wei, Da-Ming

2017-12-01

GRB 111005A, a long-duration gamma-ray burst (GRB) that occurred within a metal-rich environment that lacks massive stars with {M}{ZAMS}≥slant 15 {M}⊙ , is not coincident with supernova emission down to a stringent limit and thus should be classified as a “long-short” GRB (lsGRB; also known as an SN-less long GRB or hybrid GRB), like GRB 060505 and GRB 060614. In this work, we show that in the neutron star merger model the non-detection of the optical/infrared emission of GRB 111005A requires sub-relativistic neutron-rich ejecta with a mass of ≤slant 0.01 {M}⊙ , which is (significantly) less massive than that of GRB 130603B, GRB 060614, GRB 050709, and GRB 170817A. The lsGRBs are found to have a high rate density and the neutron star merger origin model can be unambiguously tested by the joint observations of the second-generation gravitational-wave (GW) detectors and the full-sky gamma-ray monitors such as Fermi-GBM and the proposed GECAM. If no lsGRB/GW association is observed in the 2020s, alternative scenarios have to be systematically investigated. With the detailed environmental information achievable for the nearby events, a novel kind of merger or explosion origin may be identified.

High-Energy Electromagnetic Offline Follow-Up of Ligo-Virgo Gravitational-Wave Binary Coalescence Candidate Events

NASA Technical Reports Server (NTRS)

Blackburn, L.; Briggs, M. S.; Camp, J.; Christensen, N.; Connaughton, V.; Jenke, P.; Remillard, R. A.; Veitch, J.

2015-01-01

We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterparts in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15-20 percent.

HIGH-ENERGY ELECTROMAGNETIC OFFLINE FOLLOW-UP OF LIGO-VIRGO GRAVITATIONAL-WAVE BINARY COALESCENCE CANDIDATE EVENTS

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

Blackburn, L.; Camp, J.; Briggs, M. S.

2015-03-15

We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterpartsmore » in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15–20%.« less

Extreme particle acceleration in the microquasar Cygnus X-3.

PubMed

Tavani, M; Bulgarelli, A; Piano, G; Sabatini, S; Striani, E; Evangelista, Y; Trois, A; Pooley, G; Trushkin, S; Nizhelskij, N A; McCollough, M; Koljonen, K I I; Pucella, G; Giuliani, A; Chen, A W; Costa, E; Vittorini, V; Trifoglio, M; Gianotti, F; Argan, A; Barbiellini, G; Caraveo, P; Cattaneo, P W; Cocco, V; Contessi, T; D'Ammando, F; Del Monte, E; De Paris, G; Di Cocco, G; Di Persio, G; Donnarumma, I; Feroci, M; Ferrari, A; Fuschino, F; Galli, M; Labanti, C; Lapshov, I; Lazzarotto, F; Lipari, P; Longo, F; Mattaini, E; Marisaldi, M; Mastropietro, M; Mauri, A; Mereghetti, S; Morelli, E; Morselli, A; Pacciani, L; Pellizzoni, A; Perotti, F; Picozza, P; Pilia, M; Prest, M; Rapisarda, M; Rappoldi, A; Rossi, E; Rubini, A; Scalise, E; Soffitta, P; Vallazza, E; Vercellone, S; Zambra, A; Zanello, D; Pittori, C; Verrecchia, F; Giommi, P; Colafrancesco, S; Santolamazza, P; Antonelli, A; Salotti, L

2009-12-03

Super-massive black holes in active galaxies can accelerate particles to relativistic energies, producing jets with associated gamma-ray emission. Galactic 'microquasars', which are binary systems consisting of a neutron star or stellar-mass black hole accreting gas from a companion star, also produce relativistic jets, generally together with radio flares. Apart from an isolated event detected in Cygnus X-1, there has hitherto been no systematic evidence for the acceleration of particles to gigaelectronvolt or higher energies in a microquasar, with the consequence that we are as yet unsure about the mechanism of jet energization. Here we report four gamma-ray flares with energies above 100 MeV from the microquasar Cygnus X-3 (an exceptional X-ray binary that sporadically produces radio jets). There is a clear pattern of temporal correlations between the gamma-ray flares and transitional spectral states of the radio-frequency and X-ray emission. Particle acceleration occurred a few days before radio-jet ejections for two of the four flares, meaning that the process of jet formation implies the production of very energetic particles. In Cygnus X-3, particle energies during the flares can be thousands of times higher than during quiescent states.

Discovery of a Hand X-Ray Source, SAX J0635+0533, in the Error Box of the Gamma-Ray Source 2EG J0635+0521

NASA Technical Reports Server (NTRS)

Kaaret, P.; Piraino, S.; Halpern, Jules P.; Eracleous, M.; Oliversen, Ronald (Technical Monitor)

2001-01-01

We have discovered an X-ray source, SAX J0635+0533, with a hard spectrum within the error box of the GeV gamma-ray source in Monoceros, 2EG J0635+0521. The unabsorbed flux from the source is 1.2 x 10(exp -11) ergs /sq cm s in the 2-10 keV band. The X-ray spectrum is consistent with a simple power-law model with absorption. The photon index is 1.50 +/- 0.08, and we detect emission out to 40 keV. Optical observations identify a counterpart with a V magnitude of 12.8. The counterpart has broad emission lines and the colors of an early B-type star. If the identification of the X-ray/optical source with the gamma-ray source is correct, then the source would be a gamma-ray-emitting X-ray binary.

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. 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.; 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.; Nanda Kumar, D.; 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.; 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.

Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A

DOE PAGES

Abbott, B. P.; Abbott, R.; Abbott, T. D.; ...

2017-10-16

On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance ismore » $$5.0\\times {10}^{-8}$$. We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of $$(+1.74\\pm 0.05)\\,{\\rm{s}}$$ between GRB 170817A and GW170817 to: (i) constrain the difference between the speed of gravity and the speed of light to be between $$-3\\times {10}^{-15}$$ and $$+7\\times {10}^{-16}$$ times the speed of light, (ii) place new bounds on the violation of Lorentz invariance, (iii) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1–1.4 per year during the 2018–2019 observing run and 0.3–1.7 per year at design sensitivity.« less

Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A

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.; Aloy, M. 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. R.; Constancio, M., Jr.; 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.; 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.; 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, 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.; 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; Burns, E.; Veres, P.; Kocevski, D.; Racusin, J.; Goldstein, A.; Connaughton, V.; Briggs, M. S.; Blackburn, L.; Hamburg, R.; Hui, C. M.; von Kienlin, A.; McEnery, J.; Preece, R. D.; Wilson-Hodge, C. A.; Bissaldi, E.; Cleveland, W. H.; Gibby, M. H.; Giles, M. M.; Kippen, R. M.; McBreen, S.; Meegan, C. A.; Paciesas, W. S.; Poolakkil, S.; Roberts, O. J.; Stanbro, M.; Gamma-ray Burst Monitor, (Fermi; Savchenko, V.; Ferrigno, C.; Kuulkers, E.; Bazzano, A.; Bozzo, E.; Brandt, S.; Chenevez, J.; Courvoisier, T. J.-L.; Diehl, R.; Domingo, A.; Hanlon, L.; Jourdain, E.; Laurent, P.; Lebrun, F.; Lutovinov, A.; Mereghetti, S.; Natalucci, L.; Rodi, J.; Roques, J.-P.; Sunyaev, R.; Ubertini, P.; (INTEGRAL

2017-10-01

On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance is 5.0× {10}-8. We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of (+1.74+/- 0.05) {{s}} between GRB 170817A and GW170817 to: (I) constrain the difference between the speed of gravity and the speed of light to be between -3× {10}-15 and +7× {10}-16 times the speed of light, (II) place new bounds on the violation of Lorentz invariance, (III) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1-1.4 per year during the 2018-2019 observing run and 0.3-1.7 per year at design sensitivity.

Gravitational Waves and Gamma-Rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A

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

Abbott, B. P.; Abbott, R.; Abbott, T. D.

On 2017 August 17, the gravitational-wave event GW170817 was observed by the Advanced LIGO and Virgo detectors, and the gamma-ray burst (GRB) GRB 170817A was observed independently by the Fermi Gamma-ray Burst Monitor, and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory. The probability of the near-simultaneous temporal and spatial observation of GRB 170817A and GW170817 occurring by chance ismore » $$5.0\\times {10}^{-8}$$. We therefore confirm binary neutron star mergers as a progenitor of short GRBs. The association of GW170817 and GRB 170817A provides new insight into fundamental physics and the origin of short GRBs. We use the observed time delay of $$(+1.74\\pm 0.05)\\,{\\rm{s}}$$ between GRB 170817A and GW170817 to: (i) constrain the difference between the speed of gravity and the speed of light to be between $$-3\\times {10}^{-15}$$ and $$+7\\times {10}^{-16}$$ times the speed of light, (ii) place new bounds on the violation of Lorentz invariance, (iii) present a new test of the equivalence principle by constraining the Shapiro delay between gravitational and electromagnetic radiation. We also use the time delay to constrain the size and bulk Lorentz factor of the region emitting the gamma-rays. GRB 170817A is the closest short GRB with a known distance, but is between 2 and 6 orders of magnitude less energetic than other bursts with measured redshift. A new generation of gamma-ray detectors, and subthreshold searches in existing detectors, will be essential to detect similar short bursts at greater distances. Finally, we predict a joint detection rate for the Fermi Gamma-ray Burst Monitor and the Advanced LIGO and Virgo detectors of 0.1–1.4 per year during the 2018–2019 observing run and 0.3–1.7 per year at design sensitivity.« less

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

Valle, Massimo Della; International Center for Relativistic Astrophysics Network, Piazzale della Repubblica 10, I-65122, Pescara

I’ll review the status of the Supernova/Gamma-Ray Burst connection. Several pieces of evidence suggest that long duration Gamma-ray Bursts are associated with bright SNe-Ic. However recent works suggest that GRBs might be produced in tight binary systems composed of a massive carbon-oxygen cores and a neutron star companion. Current estimates of the SN and GRB rates yield a ratio GRB/SNe-Ibc in the range ∼ 0.4% − 3%.

X-ray Follow-ups of XSS J12270-4859: A Low-mass X-ray Binary with Gamma-ray Fermi-LAT Association

NASA Technical Reports Server (NTRS)

deMartino, D.; Belloni, T.; Falanga, M.; Papitto, A.; Motta, S.; Pellizzoni, A.; Evangelista, Y.; Piano, G.; Masetti, N.; Mouchet, M.;

Accretion states in X-ray binaries and their connection to GeV emission

NASA Astrophysics Data System (ADS)

Koerding, Elmar

Accretion onto compact objects is intrinsically a multi-wavelength phenomenon: it shows emis-sion components visible from the radio to GeV bands. In X-ray binaries one can well observe the evolution of a single source under changes of the accretion rate and thus study the interplay between the different emission components.I will introduce the phenomenology of X-ray bina-ries and their accretion states and present our current understanding of the interplay between the optically thin and optically thick part of the accretion flow and the jet.The recent detection of the Fermi Large Area Telescope of a variable high-energy source coinciding with the position of the x-ray binary Cygnus X-3 will be presented. Its identification with Cygnus X-3 has been secured by the detection of its orbital period in gamma rays, as well as the correlation of the LAT flux with radio emission from the relativistic jets of Cygnus X-3. This will be interpreted in the context of the accretion states of the X-ray binary.

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.

Three Millisecond Pulsars in Fermi LAT Unassociated Bright Sources

NASA Technical Reports Server (NTRS)

Ransom, S. M.; Ray, P. S.; Camilo, F.; Roberts, M. S. E.; Celik, O.; Wolff, M. T.; Cheung, C. C.; Kerr, M.; Pennucci, T.; DeCesar, M. E.;

Supernova remnants and pulsar wind nebulae with Imaging Atmospheric Cherenkov Telescopes (IACTs)

NASA Astrophysics Data System (ADS)

Eger, Peter

2015-08-01

The observation of very-high-energy (VHE, E > 100 GeV) gamma rays is an excellent tool to study the most energetic and violent environments in the Galaxy. This energy range is only accessible with ground-based instruments such as Imaging Atmospheric Cherenkov Telescopes (IACTs) that reconstruct the energy and direction of the primary gamma ray by observing the Cherenkov light from the induced extended air showers in Earths atmosphere. The main goals of Galactic VHE gamma-ray science are the identification of individual sources of cosmic rays (CRs), such as supernova remnants (SNRs), and the study of other extreme astrophysical objects at the highest energies, such as gamma-ray binaries and pulsar wind nebulae (PWNe). One of the main challenges is the discrimination between leptonic and hadronic gamma-ray production channels. To that end, the gamma-ray signal from each individual source needs to be brought into context with the multi-wavelength environment of the astrophysical object in question, particularly with observations tracing the density of the surrounding interstellar medium, or synchrotron radiation from relativistic electrons. In this review presented at the European Cosmic Ray Symposium 2014 (ECRS2014), the most recent developments in the field of Galactic VHE gamma-ray science are highlighted, with particular emphasis on SNRs and PWNe.

Fermi Gamma-Ray Space Telescope Science Overview

NASA Technical Reports Server (NTRS)

Thompson, David J.

2010-01-01

After more than 2 years of science operations, the Fermi Gamma-ray Space Telescope continues to survey the high-energy sky on a daily basis. In addition to the more than 1400 sources found in the first Fermi Large Area Telescope Catalog (I FGL), new results continue to emerge. Some of these are: (1) Large-scale diffuse emission suggests possible activity from the Galactic Center region in the past; (2) a gamma-ray nova was found, indicating particle acceleration in this binary system; and (3) the Crab Nebula, long thought to be a steady source, has varied in the energy ranges seen by both Fermi instruments.

Polarized Gamma-Ray Emission from the Galactic Black Hole Cygnus X-1

NASA Technical Reports Server (NTRS)

Laurent, P.; Rodriquez, J.; Wilms, J.; Bel, M. Cadolle; Pottschmidt, K.; Grinberg, V.

2011-01-01

Because of their inherently high flux allowing the detection of clear signals, black hole X-ray binaries are interesting candidates for polarization studies, even if no polarization signals have been observed from them before. Such measurements would provide further detailed insight into these sources' emission mechanisms. We measured the polarization of the gamma-ray emission from the black hole binary system Cygnus X-I with the INTEGRAL/IBIS telescope. Spectral modeling ofthe data reveals two emission mechanisms: The 250-400 keY data are consistent with emission dominated by Compton scattering on thermal electrons and are weakly polarized. The second spectral component seen in the 400keV-2MeV band is by contrast strongly polarized, revealing that the MeV emission is probably related to the jet first detected in the radio band.

Yet Another Model for the Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Leonard, P. J. T.

2000-05-01

We consider whether a gamma-ray burst can result from a merger between a neutron star and a massive main-sequence star in a binary system following a supernova explosion. The scenario for how this can happen is outlined in Leonard, Hills & Dewey 1994, ApJ, 423, L19-L22. The initially more massive star in a massive binary system evolves and undergoes core collapse to produce a neutron star and supernova. Since the outer layers of the originally more massive star have been transferred to the other star, then the supernova may be hydrogen deficient. The newly-formed neutron star receives a random kick during the explosion. In a small fraction of the cases, the kick has the appropriate direction and amplitude to remove most of the orbital angular momentum of the post-supernova binary system. The result is an orbit with a pericenter smaller than the radius of the non-exploding star. The neutron star rather quickly becomes embedded in the other star, and sinks to its center, giving the envelope of the merged object a lot of rotational angular momentum in the process. Leonard, Hills & Dewey estimate the rate of this process in the Galaxy to be 0.06 per square kpc per Myr for secondaries more massive than 15 solar masses. The fate of the merged object has been the source of much speculation, and we shall assume that a collapsar-like scenario results. That is, the neutron star experiences runaway accretion, collapses into a black hole, which continues to accrete, and produces a pair of jets that bore their way out of the merged object. Observers who lie in the direction of either jet will see a gamma-ray burst. Roughly 1% of supernovae in massive binary systems result in neutron stars quickly becoming embedded in the secondaries, and of those which produce black holes, only 1% would be observable as gamma-ray bursts, if the jets are beamed into 1% of the sky.

Distribution of compact object mergers around galaxies

NASA Astrophysics Data System (ADS)

Bulik, T.; Belczyński, K.; Zbijewski, W.

1999-09-01

Compact object mergers are one of the favoured models of gamma ray bursts (GRB). Using a binary population synthesis code we calculate properties of the population of compact object binaries; e.g. lifetimes and velocities. We then propagate them in galactic potentials and find their distribution in relation to the host.

Multiwavelength observations of the TeV binary LS I +61° 303 with Veritas, Fermi-LAT, and Swift/xrt during a TeV outburst

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

Aliu, E.; Archambault, S.; Behera, B.

2013-12-10

We present the results of a multiwavelength observational campaign on the TeV binary system LS I +61° 303 with the VERITAS telescope array (>200 GeV), Fermi-LAT (0.3-300 GeV), and Swift/XRT (2-10 keV). The data were taken from 2011 December through 2012 January and show a strong detection in all three wavebands. During this period VERITAS obtained 24.9 hr of quality selected livetime data in which LS I +61° 303 was detected at a statistical significance of 11.9σ. These TeV observations show evidence for nightly variability in the TeV regime at a post-trial significance of 3.6σ. The combination of the simultaneouslymore » obtained TeV and X-ray fluxes do not demonstrate any evidence for a correlation between emission in the two bands. For the first time since the launch of the Fermi satellite in 2008, this TeV detection allows the construction of a detailed MeV-TeV spectral energy distribution from LS I +61° 303. This spectrum shows a distinct cutoff in emission near 4 GeV, with emission seen by the VERITAS observations following a simple power-law above 200 GeV. This feature in the spectrum of LS I +61° 303, obtained from overlapping observations with Fermi-LAT and VERITAS, may indicate that there are two distinct populations of accelerated particles producing the GeV and TeV emission.« less

Wind-jet interaction in high-mass X-ray binaries

NASA Astrophysics Data System (ADS)

Zdziarski, Andrzej

2016-07-01

Jets in high-mass X-ray binaries can strongly interact with the stellar wind from the donor. The interaction leads, in particular, to formation of recollimation shocks. The shocks can then accelerate electrons in the jet and lead to enhanced emission, observable in the radio and gamma-ray bands. DooSoo, Zdziarski & Heinz (2016) have formulated a condition on the maximum jet power (as a function of the jet velocity and wind rate and velocity) at which such shocks form. This criterion can explain the large difference in the radio and gamma-ray loudness between Cyg X-1 and Cyg X-3. The orbital modulation of radio emission observed in Cyg X-1 and Cyg X-3 allows a measurement of the location of the height along the jet where the bulk of emission at a given frequency occurs. Strong absorption of X-rays in the wind of Cyg X-3 is required to account for properties of the correlation of the radio emission with soft and hard X-rays. That absorption can also account for the unusual spectral and timing X-ray properties of this source.

A new NIST primary standardization of 18F.

PubMed

Fitzgerald, R; Zimmerman, B E; Bergeron, D E; Cessna, J C; Pibida, L; Moreira, D S

2014-02-01

A new primary standardization of (18)F by NIST is reported. The standard is based on live-timed beta-gamma anticoincidence counting with confirmatory measurements by three other methods: (i) liquid scintillation (LS) counting using CIEMAT/NIST (3)H efficiency tracing; (ii) triple-to-double coincidence ratio (TDCR) counting; and (iii) NaI integral counting and HPGe γ-ray spectrometry. The results are reported as calibration factors for NIST-maintained ionization chambers (including some "dose calibrators"). The LS-based methods reveal evidence for cocktail instability for one LS cocktail. Using an ionization chamber to link this work with previous NIST results, the new value differs from the previous reports by about 4%, but appears to be in good agreement with the key comparison reference value (KCRV) of 2005. © 2013 Published by Elsevier Ltd.

A population of gamma-ray millisecond pulsars seen with the Fermi Large Area Telescope.

PubMed

Abdo, A A; Ackermann, M; Ajello, M; Atwood, W B; Axelsson, M; Baldini, L; Ballet, J; Barbiellini, G; Baring, M G; Bastieri, D; Baughman, B M; Bechtol, K; Bellazzini, R; Berenji, B; Bignami, G F; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Burnett, T H; Caliandro, G A; Cameron, R A; Camilo, F; Caraveo, P A; Carlson, P; Casandjian, J M; Cecchi, C; Celik, O; Charles, E; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cognard, I; Cohen-Tanugi, J; Cominsky, L R; Conrad, J; Corbet, R; Cutini, S; Dermer, C D; Desvignes, G; de Angelis, A; de Luca, A; de Palma, F; Digel, S W; Dormody, M; do Couto e Silva, E; Drell, P S; Dubois, R; Dumora, D; Edmonds, Y; Farnier, C; Favuzzi, C; Fegan, S J; Focke, W B; Frailis, M; Freire, P C C; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giebels, B; Giglietto, N; Giordano, F; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M H; Grove, J E; Guillemot, L; Guiriec, S; Hanabata, Y; Harding, A K; Hayashida, M; Hays, E; Hobbs, G; Hughes, R E; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Johnston, S; Kamae, T; Katagiri, H; Kataoka, J; Kawai, N; Kerr, M; Knödlseder, J; Kocian, M L; Kramer, M; Kuss, M; Lande, J; Latronico, L; Lemoine-Goumard, M; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Madejski, G M; Makeev, A; Manchester, R N; Marelli, M; Mazziotta, M N; McConville, W; McEnery, J E; McLaughlin, M A; Meurer, C; Michelson, P F; Mitthumsiri, W; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nolan, P L; Norris, J P; Nuss, E; Ohsugi, T; Omodei, N; Orlando, E; Ormes, J F; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piron, F; Porter, T A; Rainò, S; Rando, R; Ransom, S M; Ray, P S; Razzano, M; Rea, N; Reimer, A; Reimer, O; Reposeur, T; Ritz, S; Rochester, L S; Rodriguez, A Y; Romani, R W; Roth, M; Ryde, F; Sadrozinski, H F W; Sanchez, D; Sander, A; Saz Parkinson, P M; Scargle, J D; Schalk, T L; Sgrò, C; Siskind, E J; Smith, D A; Smith, P D; Spandre, G; Spinelli, P; Stappers, B W; Starck, J L; Striani, E; Strickman, M S; Suson, D J; Tajima, H; Takahashi, H; Tanaka, T; Thayer, J B; Thayer, J G; Theureau, G; Thompson, D J; Thorsett, S E; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Van Etten, A; Vasileiou, V; Venter, C; Vilchez, N; Vitale, V; Waite, A P; Wallace, E; Wang, P; Watters, K; Webb, N; Weltevrede, P; Winer, B L; Wood, K S; Ylinen, T; Ziegler, M

2009-08-14

Pulsars are born with subsecond spin periods and slow by electromagnetic braking for several tens of millions of years, when detectable radiation ceases. A second life can occur for neutron stars in binary systems. They can acquire mass and angular momentum from their companions, to be spun up to millisecond periods and begin radiating again. We searched Fermi Large Area Telescope data for pulsations from all known millisecond pulsars (MSPs) outside of globular clusters, using rotation parameters from radio telescopes. Strong gamma-ray pulsations were detected for eight MSPs. The gamma-ray pulse profiles and spectral properties resemble those of young gamma-ray pulsars. The basic emission mechanism seems to be the same for MSPs and young pulsars, with the emission originating in regions far from the neutron star surface.

All-Sky Earth Occultation Observations with the Fermi Gamma-Ray Burst Monitor

NASA Technical Reports Server (NTRS)

Wilson-Hodge, C. A.; Beklen, E.; Bhat, P. N.; Briggs, M.; Camero-Arranz, A.; Case, G.; Jenke, P.; Chaplin, V.; Cherry, M.; Connaughton, V.;

The little-studied cluster Berkeley 90. I. LS III +46 11: a very massive O3.5 If* + O3.5 If* binary

NASA Astrophysics Data System (ADS)

Maíz Apellániz, J.; Negueruela, I.; Barbá, R. H.; Walborn, N. R.; Pellerin, A.; Simón-Díaz, S.; Sota, A.; Marco, A.; Alonso-Santiago, J.; Sanchez Bermudez, J.; Gamen, R. C.; Lorenzo, J.

2015-07-01

Context. It appears that most (if not all) massive stars are born in multiple systems. At the same time, the most massive binaries are hard to find owing to their low numbers throughout the Galaxy and the implied large distances and extinctions. Aims: We want to study LS III +46 11, identified in this paper as a very massive binary; another nearby massive system, LS III +46 12; and the surrounding stellar cluster, Berkeley 90. Methods: Most of the data used in this paper are multi-epoch high S/N optical spectra, although we also use Lucky Imaging and archival photometry. The spectra are reduced with dedicated pipelines and processed with our own software, such as a spectroscopic-orbit code, CHORIZOS, and MGB. Results: LS III +46 11 is identified as a new very early O-type spectroscopic binary [O3.5 If* + O3.5 If*] and LS III +46 12 as another early O-type system [O4.5 V((f))]. We measure a 97.2-day period for LS III +46 11 and derive minimum masses of 38.80 ± 0.83 M⊙ and 35.60 ± 0.77 M⊙ for its two stars. We measure the extinction to both stars, estimate the distance, search for optical companions, and study the surrounding cluster. In doing so, a variable extinction is found as well as discrepant results for the distance. We discuss possible explanations and suggest that LS III +46 12 may be a hidden binary system where the companion is currently undetected.

Probing massive stars around gamma-ray burst progenitors

NASA Astrophysics Data System (ADS)

Lu, Wenbin; Kumar, Pawan; Smoot, George F.

2015-10-01

Long gamma-ray bursts (GRBs) are produced by ultra-relativistic jets launched from core collapse of massive stars. Most massive stars form in binaries and/or in star clusters, which means that there may be a significant external photon field (EPF) around the GRB progenitor. We calculate the inverse-Compton scattering of EPF by the hot electrons in the GRB jet. Three possible cases of EPF are considered: the progenitor is (I) in a massive binary system, (II) surrounded by a Wolf-Rayet-star wind and (III) in a dense star cluster. Typical luminosities of 1046-1050 erg s-1 in the 1-100 GeV band are expected, depending on the stellar luminosity, binary separation (I), wind mass-loss rate (II), stellar number density (III), etc. We calculate the light curve and spectrum in each case, taking fully into account the equal-arrival time surfaces and possible pair-production absorption with the prompt γ-rays. Observations can put constraints on the existence of such EPFs (and hence on the nature of GRB progenitors) and on the radius where the jet internal dissipation process accelerates electrons.

Current Topics in Gamma-Ray Astrophysics

PubMed Central

Mathews, Grant J.; Maronetti, P.; Salmonson, Jay; Wilson, J. R.

2000-01-01

This paper reports on recent progress toward unraveling the origin of gamma-ray bursts. It is concluded that neutron-star binaries are one of the few remaining candidates. A model is proposed based upon general relativistic hydrodynamic studies which indicate a new physical process by which to power a gamma-ray burst. Relativistically driven compression, heating, and collapse of the individual neutron stars can occur many seconds before inspiral and merger. This compression may produce a neutrino burst of ∼1053 ergs lasting several seconds. The associated thermal neutrino emission produces an e+–e − pair plasma by vv¯ annihilation. We show first results of a simulated burst which produces ∼1051 erg in γ rays of the correct spectral and temporal properties. PMID:27551592

Current Topics in Gamma-Ray Astrophysics.

PubMed

Mathews, G J; Maronetti, P; Salmonson, J; Wilson, J R

2000-01-01

This paper reports on recent progress toward unraveling the origin of gamma-ray bursts. It is concluded that neutron-star binaries are one of the few remaining candidates. A model is proposed based upon general relativistic hydrodynamic studies which indicate a new physical process by which to power a gamma-ray burst. Relativistically driven compression, heating, and collapse of the individual neutron stars can occur many seconds before inspiral and merger. This compression may produce a neutrino burst of ∼10(53) ergs lasting several seconds. The associated thermal neutrino emission produces an e (+)-e (-) pair plasma by [Formula: see text] annihilation. We show first results of a simulated burst which produces ∼10(51) erg in γ rays of the correct spectral and temporal properties.

Hercules X-1: Pulsed gamma-rays detected above 150 GeV

NASA Technical Reports Server (NTRS)

Cawley, M. F.; Fegan, D. J.; Gibbs, K. G.; Gorham, P. W.; Kenny, S.; Lamb, R. C.; Liebing, D. F.; Porter, N. A.; Stenger, V. J.; Weekes, T. C.

1985-01-01

The 1.24 second binary pulsar Her X-1, first observed in X-rays in 1971 by UHURU has now been seen as a sporadic gamma ray source from 1 TeV up to at least 500 TeV. In addition, reprocessed optical and infrared pulses are seen from the companion star HZ Herculis. Thus measurements of the Her X-1/HZ Herculis system span 15 decades in energy, rivaling both the Crab pulsar and Cygnus X-3 in this respect for a discrete galactic source.

GLAST Science Across Wavelengths

NASA Astrophysics Data System (ADS)

Blandford, R. D.

2006-12-01

The GLAST satellites is almost guaranteed to revolutionize GeV gamma ray astronomy because of the great discoveries that are being made at hard X-ray energy by the Suzaku and Swift satellites and in the TeV range using the H.E.S.S. and Magic telescopes. Unidentified EGRET sources are likely to be identified and new and fainter sources will be found. Known classes of sources blazars, pulsars, gamma ray bursts, supernova remnants, binary X-ray sources and so on will be monitored in much greater detail. Finally, there is the need to limit or even detect dark matter through its annihilation signature. The science that will emerge from GLAST will be determined in large measure by the effort that is put into multiwavelength observing. This will require significant commitments of observing time for monitoring pulsar arrival times, measuring faint galaxy spectra, detecting GeV gamma rays gamma ray bursts and so on. In this talk I will attempt to summarize current thinking on the GLAST multi-wavelength observing program and propose some new approaches.

VizieR Online Data Catalog: Hα observations of LSI+61 303 (Zamanov+, 2013)

NASA Astrophysics Data System (ADS)

Zamanov, R.; Stoyanov, K.; Marti, J.; Tomov, N. A.; Belcheva, G.; Luque-Escamilla, P. L.; Latev, G.

2013-09-01

Optical spectroscopic observations of the Hα emission line (137 spectra obtained during the period of September 1998 - January 2013) are presented for the the radio- and gamma-ray-emitting Be/X-ray binary LSI+61 303. (2 data files).

2FGL J1311.7-3429 JOINS THE BLACK WIDOW CLUB

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

Romani, Roger W.

2012-08-01

We have found an optical/X-ray counterpart candidate for the bright, but presently unidentified, Fermi source 2FGL J1311.7-3429. This counterpart undergoes large-amplitude quasi-sinusoidal optical modulation with a 1.56 hr (5626 s) period. The modulated flux is blue at peak, with T{sub eff} Almost-Equal-To 14, 000 K, and redder at minimum. Superimposed on this variation are dramatic optical flares. Archival X-ray data suggest modest binary modulation, but no eclipse. With the {gamma}-ray properties, this appears to be another black-widow-type millisecond pulsar. If confirmation pulses can be found in the GeV data, this binary will have the shortest orbital period of any knownmore » spin-powered pulsar. The flares may be magnetic events on the rapidly rotating companion or shocks in the companion-stripping wind. While this may be a radio-quiet millisecond pulsar, we show that such objects are a small subset of the {gamma}-ray pulsar population.« less

Observations of short-duration gamma-ray bursts

NASA Astrophysics Data System (ADS)

Pozanenko, Alexei; Volnova, Alina; Tungalag, Namkhai; Elenin, Leonid; Molotov, Igor; Voropaev, Victor; Schmalz, Sergey

2014-09-01

Gamma-ray bursts (GRB) are the most powerful cosmological catastrophes in the Universe, with energy releases of 1048 - 1053 erg within a few tens of seconds. It is widely believed that progenitors of the short-duration class of GRB can be merging relativistic binary systems such as a neutron star (NS) and a black hole (BH) or NS-NS. We review the physics of GRBs, their phenomenological properties and observational evidence of GRBs, emphasizing optical observations of GRBs from Mongolia.

Discovery of two millisecond pulsars in Fermi sources with the Nancay Radio Telescope

DOE PAGES

Cognard, I.; Guillemot, L.; Johnson, Tyrel J.; ...

2011-04-14

Here, we report the discovery of two millisecond pulsars in a search for radio pulsations at the positions of Fermi-Large Area Telescope sources with no previously known counterparts, using the Nançay Radio Telescope. The two millisecond pulsars, PSRs J2017+0603 and J2302+4442, have rotational periods of 2.896 and 5.192 ms and are both in binary systems with low-eccentricity orbits and orbital periods of 2.2 and 125.9 days, respectively, suggesting long recycling processes. Gamma-ray pulsations were subsequently detected for both objects, indicating that they power the associated Fermi sources in which they were found. The gamma-ray light curves and spectral properties aremore » similar to those of previously detected gamma-ray millisecond pulsars. Detailed modeling of the observed radio and gamma-ray light curves shows that the gamma-ray emission seems to originate at high altitudes in their magnetospheres. Additionally, X-ray observations revealed the presence of an X-ray source at the position of PSR J2302+4442, consistent with thermal emission from a neutron star. These discoveries along with the numerous detections of radio-loud millisecond pulsars in gamma rays suggest that many Fermi sources with no known counterpart could be unknown millisecond pulsars.« less

Variability of the symbiotic X-ray binary GX 1+4. Enhanced activity near periastron passage

NASA Astrophysics Data System (ADS)

Iłkiewicz, Krystian; Mikołajewska, Joanna; Monard, Berto

2017-05-01

Context. GX 1+4 belongs to a rare class of X-ray binaries with red giant donors, symbiotic X-ray binaries. It has a history of complicated variability on multiple timescales in the optical light and X-rays. The nature of this variability remains poorly understood. Aims: We aim to study variability of GX 1+4 on long timescale in X-ray and optical bands. Methods: We took X-ray observations from the INTEGRAL Soft Gamma-Ray Imager and RXTE All Sky Monitor. Optical observations were made with the INTEGRAL Optical Monitoring Camera. Results: The variability of GX 1+4 both in optical light and hard X-ray emission (>17 keV) is dominated by 50-70 d quasi-periodic changes. The amplitude of this variability is highest during the periastron passage, while during the potential neutron star eclipse the system is always at minimum. This confirms the 1161 d orbital period that has had been proposed for the system based on radial velocity curve. Neither the quasi-periodic variability or the orbital period are detected in soft X-ray emission (1.3-12.2 keV), where the binary shows no apparent periodicity.

Recognition of compact astrophysical objects

NASA Technical Reports Server (NTRS)

Ogelman, H. (Editor); Rothschild, R. (Editor)

1977-01-01

NASA's Laboratory for High Energy Astrophysics and the Dept. of Physics and Astrophysics at the Univ. of Md. collaberated on a graduate level course with this title. This publication is an edited version of notes used as the course text. Topics include stellar evolution, pulsars, binary stars, X-ray signatures, gamma ray sources, and temporal analysis of X-ray data.

Can comet clouds around neutron stars explain gamma-ray bursts?

NASA Technical Reports Server (NTRS)

Tremaine, S.; Zytkow, A. N.

1986-01-01

The proposal of Harwit and Salpeter (1973) that gamma-ray bursts are due to impacts of comets onto neutron stars is examined further. It is assumed that most stars are formed with comet clouds similar to the Oort comet cloud which surrounds the sun, and it is suggested that there are at least four mechanisms by wich neutron stars may be formed while retaining their comet clouds: a spherically symmetric supernova explosion in an isolated star, accretion-induced collapse of a white dwarf in a cataclysmic variable with a very low mass secondary, accretion-induced collapse of a white dwarf in a wide binary with a low-mass giant companion, and coalescence of a close binary composed of two white dwarfs. Estimates are given of the cometary impact rates for such systems. It is suggested that if the wide binary scenario is correct, optical bursts may arise from the impact of comets onto the white dwarf remnant of the giant companion.

High-energy radiation from the relativistic jet of Cygnus X-3

NASA Astrophysics Data System (ADS)

Cerutti, B.; Dubus, G.; Henri, G.

2010-12-01

Cygnus X-3 is an accreting high-mass X-ray binary composed of a Wolf-Rayet star and an unknown compact object, possibly a black hole. The gamma-ray space telescope Fermi found definitive evidence that high-energy emission is produced in this system. We propose a scenario to explain the GeV gamma-ray emission in Cygnus X-3. In this model, energetic electron-positron pairs are accelerated at a specific location in the relativistic jet, possibly related to a recollimation shock, and upscatter the stellar photons to high energies. The comparison with Fermi observations shows that the jet should be inclined close to the line of sight and pairs should not be located within the system. Energetically speaking, a massive compact object is favored. We report also on our investigations of the gamma-ray absorption of GeV photons with the radiation emitted by a standard accretion disk in Cygnus X-3. This study shows that the gamma-ray source should not lie too close to the compact object.

FIVE NEW MILLISECOND PULSARS FROM A RADIO SURVEY OF 14 UNIDENTIFIED FERMI-LAT GAMMA-RAY SOURCES

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

Kerr, M.; Camilo, F.; Johnson, T. J.

2012-03-20

We have discovered five millisecond pulsars (MSPs) in a survey of 14 unidentified Fermi Large Area Telescope sources in the southern sky using the Parkes radio telescope. PSRs J0101-6422, J1514-4946, and J1902-5105 reside in binaries, while PSRs J1658-5324 and J1747-4036 are isolated. Using an ephemeris derived from timing observations of PSR J0101-6422 (P = 2.57 ms, DM = 12 pc cm{sup -3}), we have detected {gamma}-ray pulsations and measured its proper motion. Its {gamma}-ray spectrum (a power law of {Gamma} = 0.9 with a cutoff at 1.6 GeV) and efficiency are typical of other MSPs, but its radio and {gamma}-raymore » light curves challenge simple geometric models of emission. The high success rate of this survey-enabled by selecting {gamma}-ray sources based on their detailed spectral characteristics-and other similarly successful searches indicate that a substantial fraction of the local population of MSPs may soon be known.« less

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.

Swift J181723.1-164300 is likely a new bursting neutron star low-mass X-ray binary

NASA Astrophysics Data System (ADS)

Parikh, Aastha; Wijnands, Rudy; Degenaar, Nathalie; Altamirano, Diego

2017-08-01

On 28 July 2017 Swift/BAT triggered (#00765081) on an event corresponding to a previously unknown source (Barthelmy et al. 2017, GCN #21369, #21385). Its properties suggested it was likely a Galactic source and not a gamma-ray burst.

Discovery of gamma-ray pulsations from the transitional redback PSR J1227-4853

DOE PAGES

Johnson, Tyrel J.; Ray, Paul S.; Roy, Jayanta; ...

2015-06-10

Here, the 1.69 ms spin period of PSR J1227–4853 was recently discovered in radio observations of the low-mass X-ray binary XSS J12270–4859 following the announcement of a possible transition to a rotation-powered millisecond pulsar state, inferred from decreases in optical, X-ray, and gamma-ray flux from the source. We report the detection of significant (5σ) gamma-ray pulsations after the transition, at the known spin period, using ~1 year of data from the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The gamma-ray light curve of PSR J1227–4853 can be fit by one broad peak, which occurs at nearlymore » the same phase as the main peak in the 1.4 GHz radio profile. The partial alignment of light-curve peaks in different wavebands suggests that at least some of the radio emission may originate at high altitude in the pulsar magnetosphere, in extended regions co-located with the gamma-ray emission site. We folded the LAT data at the orbital period, both pre- and post-transition, but find no evidence for significant modulation of the gamma-ray flux. Analysis of the gamma-ray flux over the mission suggests an approximate transition time of 2012 November 30. Continued study of the pulsed emission and monitoring of PSR J1227–4853, and other known redback systems, for subsequent flux changes will increase our knowledge of the pulsar emission mechanism and transitioning systems.« less

Upper Limits on the Rates of Binary Neutron Star and Neutron Star-Black Hole Mergers 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.; 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., Jr.; 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.; 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.; 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.; 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.; 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.; 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.; 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. 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.; Perri, L. M.; 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.; 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, 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.; 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.; 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

2016-12-01

We report here the non-detection of gravitational waves from the merger of binary-neutron star systems and neutron star-black hole systems during the first observing run of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO). In particular, we searched for gravitational-wave signals from binary-neutron star systems with component masses \\in [1,3] {M}⊙ and component dimensionless spins <0.05. We also searched for neutron star-black hole systems with the same neutron star parameters, black hole mass \\in [2,99] {M}⊙ , and no restriction on the black hole spin magnitude. We assess the sensitivity of the two LIGO detectors to these systems and find that they could have detected the merger of binary-neutron star systems with component mass distributions of 1.35 ± 0.13 M ⊙ at a volume-weighted average distance of ˜70 Mpc, and for neutron star-black hole systems with neutron star masses of 1.4 M ⊙ and black hole masses of at least 5 M ⊙, a volume-weighted average distance of at least ˜110 Mpc. From this we constrain with 90% confidence the merger rate to be less than 12,600 Gpc-3 yr-1 for binary-neutron star systems and less than 3600 Gpc-3 yr-1 for neutron star-black hole systems. We discuss the astrophysical implications of these results, which we find to be in conflict with only the most optimistic predictions. However, we find that if no detection of neutron star-binary mergers is made in the next two Advanced LIGO and Advanced Virgo observing runs we would place significant constraints on the merger rates. Finally, assuming a rate of {10}-7+20 Gpc-3 yr-1, short gamma-ray bursts beamed toward the Earth, and assuming that all short gamma-ray bursts have binary-neutron star (neutron star-black hole) progenitors, we can use our 90% confidence rate upper limits to constrain the beaming angle of the gamma-ray burst to be greater than 2\\buildrel{\\circ}\\over{.} {3}-1.1+1.7 (4\\buildrel{\\circ}\\over{.} {3}-1.9+3.1).

Gamma-ray bursts at high and very high energies

NASA Astrophysics Data System (ADS)

Piron, Frédéric

2016-06-01

Gamma-Ray Bursts (GRBs) are extra-galactic and extremely energetic transient emissions of gamma rays, which are thought to be associated with the death of massive stars or the merger of compact objects in binary systems. Their huge luminosities involve the presence of a newborn stellar-mass black hole emitting a relativistic collimated outflow, which accelerates particles and produces non-thermal emissions from the radio domain to the highest energies. In this article, I review recent progresses in the understanding of GRB jet physics above 100 MeV, based on Fermi observations of bright GRBs. I discuss the physical implications of these observations and their impact on GRB modeling, and I present some prospects for GRB observation at very high energies in the near future.

High-energy Emission from Nonrelativistic Radiative Shocks: Application to Gamma-Ray Novae

NASA Astrophysics Data System (ADS)

Vurm, Indrek; Metzger, Brian D.

2018-01-01

The observation of GeV gamma-rays from novae by Fermi/LAT demonstrates that the nonrelativistic radiative shocks in these systems can accelerate particles to energies of at least ∼10 GeV. The low-energy extension of the same nonthermal particle distribution inevitably gives rise to emission in the hard X-ray band. Above ≳ 10 {keV}, this radiation can escape the system without significant absorption/attenuation, and can potentially be detected by NuSTAR. We present theoretical models for hard X-ray and gamma-ray emission from radiative shocks in both leptonic and hadronic scenarios, accounting for the rapid evolution of the downstream properties due to the fast cooling of thermal plasma. We find that due to strong Coulomb losses, only a fraction of {10}-4{--}{10}-3 of the gamma-ray luminosity is radiated in the NuSTAR band; nevertheless, this emission could be detectable simultaneously with the LAT emission in bright gamma-ray novae with a ∼50 ks exposure. The spectral slope in hard X-rays is α ≈ 0 for typical nova parameters, thus serving as a testable prediction of the model. Our work demonstrates how combined hard X-ray and gamma-ray observations can be used to constrain properties of the nova outflow (velocity, density, and mass outflow rate) and particle acceleration at the shock. A very low X-ray to gamma-ray luminosity ratio ({L}{{X}}/{L}γ ≲ 5× {10}-4) would disfavor leptonic models for the gamma-ray emission. Our model can also be applied to other astrophysical environments with radiative shocks, including SNe IIn and colliding winds in massive star binaries.

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

Johnson, Tyrel J.; Ray, Paul S.; Roy, Jayanta

Here, the 1.69 ms spin period of PSR J1227–4853 was recently discovered in radio observations of the low-mass X-ray binary XSS J12270–4859 following the announcement of a possible transition to a rotation-powered millisecond pulsar state, inferred from decreases in optical, X-ray, and gamma-ray flux from the source. We report the detection of significant (5σ) gamma-ray pulsations after the transition, at the known spin period, using ~1 year of data from the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The gamma-ray light curve of PSR J1227–4853 can be fit by one broad peak, which occurs at nearlymore » the same phase as the main peak in the 1.4 GHz radio profile. The partial alignment of light-curve peaks in different wavebands suggests that at least some of the radio emission may originate at high altitude in the pulsar magnetosphere, in extended regions co-located with the gamma-ray emission site. We folded the LAT data at the orbital period, both pre- and post-transition, but find no evidence for significant modulation of the gamma-ray flux. Analysis of the gamma-ray flux over the mission suggests an approximate transition time of 2012 November 30. Continued study of the pulsed emission and monitoring of PSR J1227–4853, and other known redback systems, for subsequent flux changes will increase our knowledge of the pulsar emission mechanism and transitioning systems.« less

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

Johnson, T. J.; Ray, P. S.; Cheung, C. C.

The 1.69 ms spin period of PSR J1227−4853 was recently discovered in radio observations of the low-mass X-ray binary XSS J12270−4859 following the announcement of a possible transition to a rotation-powered millisecond pulsar state, inferred from decreases in optical, X-ray, and gamma-ray flux from the source. We report the detection of significant (5σ) gamma-ray pulsations after the transition, at the known spin period, using ∼1 year of data from the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The gamma-ray light curve of PSR J1227−4853 can be fit by one broad peak, which occurs at nearly themore » same phase as the main peak in the 1.4 GHz radio profile. The partial alignment of light-curve peaks in different wavebands suggests that at least some of the radio emission may originate at high altitude in the pulsar magnetosphere, in extended regions co-located with the gamma-ray emission site. We folded the LAT data at the orbital period, both pre- and post-transition, but find no evidence for significant modulation of the gamma-ray flux. Analysis of the gamma-ray flux over the mission suggests an approximate transition time of 2012 November 30. Continued study of the pulsed emission and monitoring of PSR J1227−4853, and other known redback systems, for subsequent flux changes will increase our knowledge of the pulsar emission mechanism and transitioning systems.« less

New O-C Observations for 150 Algols: Insight to the Origins of Period Shifts

NASA Astrophysics Data System (ADS)

Hoffman, D. I.; Harrison, T. E.; McNamara, B. J.; Vestrand, W. T.

2005-12-01

Many eclipsing binaries of type Algol, RS CVn, and W UMa have observed orbital period shifts. Of these, many show both increasing and decreasing period shifts. Two leading explanations for these shifts are third body effects and magnetic activity changing the oblateness of the secondary, though neither one can explain all of the observed period oscillations. The first-generation Robotic Optical Transient Search Experiment (ROTSE-I) based in Los Alamos, NM, was primarily designed to look for the optical counterparts to gamma-ray bursts as well as searching for other optical transients not detected in gamma-rays. The telescope, consisting of four 200mm camera lenses, can image the entire northern sky twice in a night, which is a very useful tool in monitoring relatively bright eclipsing binaries for period shifts. The public data release from ROTSE-I, the Northern Sky Variability Survey (NSVS), spans one year of data stating in April, 1999. O-C data for 150 eclipsing binaries are presented using the NSVS data. We revisit work by Borkovits and Hegedüs on some third body candidates in several eclipsing binary systems using recent AAVSO and NSVS data. Some unusual light curves of eclipsing binaries produced from NSVS data is presented and discussed.

Anatomy of a cosmic-ray neutrino source and the Cygnus X-3 system

NASA Technical Reports Server (NTRS)

Stecker, F. W.; Harding, A. K.; Barnard, J. J.

1985-01-01

The effects of an intense beam of ultra-high energy cosmic rays from a compact object in the Cygnus X-3 binary system hitting the companion star, and of the subsequent production of secondary neutrinos, are examined. A maximum allowable beam luminosity of about 10 to the 42nd erg/s is found for a system containing a 1-10 solar mass main sequence target star. The proton beam must heat a relatively small area of the target star to satisfy observational constraints on the resulting stellar wind. With such a model, the neutrino to gamma-ray flux ratio of about 1000 can result from a combination of gamma-ray absorption and a large neutrino to gamma-ray duty cycle ratio. It is found that the high density of the atmosphere resulting from compression by the beam leads to pion cascading and a neutrino spectrum peaking at 1-10 GeV energies.

The Fermi-GBM Three-year X-Ray Burst Catalog

NASA Astrophysics Data System (ADS)

Jenke, P. A.; Linares, M.; Connaughton, V.; Beklen, E.; Camero-Arranz, A.; Finger, M. H.; Wilson-Hodge, C. A.

2016-08-01

The Fermi Gamma-ray Burst Monitor (GBM) is an all-sky gamma-ray monitor well known in the gamma-ray burst (GRB) community. Although GBM excels in detecting the hard, bright extragalactic GRBs, its sensitivity above 8 keV and its all-sky view make it an excellent instrument for the detection of rare, short-lived Galactic transients. In 2010 March, we initiated a systematic search for transients using GBM data. We conclude this phase of the search by presenting a three-year catalog of 1084 X-ray bursts. Using spectral analysis, location, and spatial distributions we classified the 1084 events into 752 thermonuclear X-ray bursts, 267 transient events from accretion flares and X-ray pulses, and 65 untriggered gamma-ray bursts. All thermonuclear bursts have peak blackbody temperatures broadly consistent with photospheric radius expansion (PRE) bursts. We find an average rate of 1.4 PRE bursts per day, integrated over all Galactic bursters within about 10 kpc. These include 33 and 10 bursts from the ultra-compact X-ray binaries 4U 0614+09 and 2S 0918-549, respectively. We discuss these recurrence times and estimate the total mass ejected by PRE bursts in our Galaxy.

Keck spectroscopy of millisecond pulsar J2215+5135: a moderate-M

DOE PAGES

Romani, Roger W.; Graham, Melissa L.; Filippenko, Alexei V.; ...

2015-08-07

We present Keck spectroscopic measurements of the millisecond pulsar binary J2215+5135. These data indicate a neutron-star (NS) massmore » $${M}_{\\mathrm{NS}}=1.6\\;{M}_{\\odot }$$, much less than previously estimated. The pulsar heats the companion face to $${T}_{D}\\approx 9000$$ K; the large heating efficiency may be mediated by the intrabinary shock dominating the X-ray light curve. At the best-fit inclination i = 88 $$^o\\atop{.}$$ 8, the pulsar should be eclipsed. Here, we find weak evidence for such eclipses in the pulsed gamma-rays; an improved radio ephemeris allows use of up to five times more Fermi-Large Area Telescope gamma-ray photons for a definitive test of this picture. If confirmed, the gamma-ray eclipse provides a novel probe of the dense companion wind and the pulsar magnetosphere.« less

Gamma-ray emission concurrent with the nova in the symbiotic binary V407 Cygni.

PubMed

Abdo, A A; Ackermann, M; Ajello, M; Atwood, W B; Baldini, L; Ballet, J; Barbiellini, G; Bastieri, D; Bechtol, K; Bellazzini, R; Berenji, B; Blandford, R D; Bloom, E D; Bonamente, E; Borgland, A W; Bouvier, A; Brandt, T J; Bregeon, J; Brez, A; Brigida, M; Bruel, P; Buehler, R; Burnett, T H; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Carrigan, S; Casandjian, J M; Cecchi, C; Celik, O; Charles, E; Chaty, S; Chekhtman, A; Cheung, C C; Chiang, J; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Corbel, S; Corbet, R; DeCesar, M E; den Hartog, P R; Dermer, C D; de Palma, F; Digel, S W; Donato, D; do Couto e Silva, E; Drell, P S; Dubois, R; Dubus, G; Dumora, D; Favuzzi, C; Fegan, S J; Ferrara, E C; Fortin, P; Frailis, M; Fuhrmann, L; Fukazawa, Y; Funk, S; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Germani, S; Giglietto, N; Giordano, F; Giroletti, M; Glanzman, T; Godfrey, G; Grenier, I A; Grondin, M-H; Grove, J E; Guiriec, S; Hadasch, D; Harding, A K; Hayashida, M; Hays, E; Healey, S E; Hill, A B; Horan, D; Hughes, R E; Itoh, R; Jean, P; Jóhannesson, G; Johnson, A S; Johnson, R P; Johnson, T J; Johnson, W N; Kamae, T; Katagiri, H; Kataoka, J; Kerr, M; Knödlseder, J; Koerding, E; Kuss, M; Lande, J; Latronico, L; Lee, S-H; Lemoine-Goumard, M; Garde, M Llena; Longo, F; Loparco, F; Lott, B; Lovellette, M N; Lubrano, P; Makeev, A; Mazziotta, M N; McConville, W; McEnery, J E; Mehault, J; Michelson, P F; Mizuno, T; Moiseev, A A; Monte, C; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nakamori, T; Naumann-Godo, M; Nestoras, I; Nolan, P L; Norris, J P; Nuss, E; Ohno, M; Ohsugi, T; Okumura, A; Omodei, N; Orlando, E; Ormes, J F; Ozaki, M; Paneque, D; Panetta, J H; Parent, D; Pelassa, V; Pepe, M; Pesce-Rollins, M; Piron, F; Porter, T A; Rainò, S; Rando, R; Ray, P S; Razzano, M; Razzaque, S; Rea, N; Reimer, A; Reimer, O; Reposeur, T; Ripken, J; Ritz, S; Romani, R W; Roth, M; Sadrozinski, H F-W; Sander, A; Parkinson, P M Saz; Scargle, J D; Schinzel, F K; Sgrò, C; Shaw, M S; Siskind, E J; Smith, D A; Smith, P D; Sokolovsky, K V; Spandre, G; Spinelli, P; Stawarz, Ł; Strickman, M S; Suson, D J; Takahashi, H; Takahashi, T; Tanaka, T; Tanaka, Y; Thayer, J B; Thayer, J G; Thompson, D J; Tibaldo, L; Torres, D F; Tosti, G; Tramacere, A; Uchiyama, Y; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vilchez, N; Vitale, V; Waite, A P; Wallace, E; Wang, P; Winer, B L; Wolff, M T; Wood, K S; Yang, Z; Ylinen, T; Ziegler, M; Maehara, H; Nishiyama, K; Kabashima, F; Bach, U; Bower, G C; Falcone, A; Forster, J R; Henden, A; Kawabata, K S; Koubsky, P; Mukai, K; Nelson, T; Oates, S R; Sakimoto, K; Sasada, M; Shenavrin, V I; Shore, S N; Skinner, G K; Sokoloski, J; Stroh, M; Tatarnikov, A M; Uemura, M; Wahlgren, G M; Yamanaka, M

2010-08-13

Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here, we report the Fermi Large Area Telescope detection of variable gamma-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particles can be accelerated effectively to produce pi(0) decay gamma-rays from proton-proton interactions. Emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.

The Animated Gamma-ray Sky Revealed by the Fermi Gamma-ray Space Telescope

ScienceCinema

Isabelle Grenier

2018-04-17

The Fermi Gamma-ray Space Telescope has been observing the sky in gamma-rays since August 2008.  In addition to breakthrough capabilities in energy coverage (20 MeV-300 GeV) and angular resolution, the wide field of view of the Large Area Telescope enables observations of 20% of the sky at any instant, and of the whole sky every three hours. It has revealed a very animated sky with bright gamma-ray bursts flashing and vanishing in minutes, powerful active galactic nuclei flaring over hours and days, many pulsars twinkling in the Milky Way, and X-ray binaries shimmering along their orbit. Most of these variable sources had not been seen by the Fermi predecessor, EGRET, and the wealth of new data already brings important clues to the origin of the high-energy emission and particles powered by the compact objects. The telescope also brings crisp images of the bright gamma-ray emission produced by cosmic-ray interactions in the interstellar medium, thus allowing to measure the cosmic nuclei and electron spectra across the Galaxy, to weigh interstellar clouds, in particular in the dark-gas phase. The telescope sensitivity at high energy will soon provide useful constraints on dark-matter annihilations in a variety of environments. I will review the current results and future prospects of the Fermi mission.

Parkes radio searches of Fermi gamma-ray sources and millisecond pulsar discoveries

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

Camilo, F.; Kerr, M.; Ray, P. S.

In a search with the Parkes radio telescope of 56 unidentified Fermi-Large Area Telescope (LAT) gamma-ray sources, we have detected 11 millisecond pulsars (MSPs), 10 of them discoveries, of which five were reported by Kerr et al. We did not detect radio pulsations from six other pulsars now known in these sources. We also describe the completed survey, which included multiple observations of many targets conducted to minimize the impact of interstellar scintillation, acceleration effects in binary systems, and eclipses. We consider that 23 of the 39 remaining sources may still be viable pulsar candidates. Furthermore, we present timing solutions and polarimetry for five of the MSPs and gamma-ray pulsations for PSR J1903–7051 (pulsations for five others were reported in the second Fermi-LAT catalog of gamma-ray pulsars). Two of the new MSPs are isolated and five are inmore » $$\\gt 1$$ day circular orbits with 0.2–0.3 $${M}_{\\odot }$$ presumed white dwarf companions. PSR J0955–6150, in a 24 day orbit with a $$\\approx 0.25$$ $${M}_{\\odot }$$ companion but eccentricity of 0.11, belongs to a recently identified class of eccentric MSPs. PSR J1036–8317 is in an 8 hr binary with a $$\\gt 0.14$$ $${M}_{\\odot }$$ companion that is probably a white dwarf. PSR J1946–5403 is in a 3 hr orbit with a $$\\gt 0.02$$ $${M}_{\\odot }$$ companion with no evidence of radio eclipses.« less

Parkes radio searches of Fermi gamma-ray sources and millisecond pulsar discoveries

DOE PAGES

Camilo, F.; Kerr, M.; Ray, P. S.; ...

2015-09-02

In a search with the Parkes radio telescope of 56 unidentified Fermi-Large Area Telescope (LAT) gamma-ray sources, we have detected 11 millisecond pulsars (MSPs), 10 of them discoveries, of which five were reported by Kerr et al. We did not detect radio pulsations from six other pulsars now known in these sources. We also describe the completed survey, which included multiple observations of many targets conducted to minimize the impact of interstellar scintillation, acceleration effects in binary systems, and eclipses. We consider that 23 of the 39 remaining sources may still be viable pulsar candidates. Furthermore, we present timing solutions and polarimetry for five of the MSPs and gamma-ray pulsations for PSR J1903–7051 (pulsations for five others were reported in the second Fermi-LAT catalog of gamma-ray pulsars). Two of the new MSPs are isolated and five are inmore » $$\\gt 1$$ day circular orbits with 0.2–0.3 $${M}_{\\odot }$$ presumed white dwarf companions. PSR J0955–6150, in a 24 day orbit with a $$\\approx 0.25$$ $${M}_{\\odot }$$ companion but eccentricity of 0.11, belongs to a recently identified class of eccentric MSPs. PSR J1036–8317 is in an 8 hr binary with a $$\\gt 0.14$$ $${M}_{\\odot }$$ companion that is probably a white dwarf. PSR J1946–5403 is in a 3 hr orbit with a $$\\gt 0.02$$ $${M}_{\\odot }$$ companion with no evidence of radio eclipses.« less

A DEEP CHANDRA OBSERVATION OF THE WOLF-RAYET + BLACK HOLE BINARY NGC 300 X-1

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

Binder, B.; Williams, B. F.; Anderson, S. F.

We have obtained a 63 ks Chandra ACIS-I observation of the Wolf-Rayet + black hole binary NGC 300 X-1. We measure rapid low-amplitude variability in the 0.35-8 keV light curve. The power density spectrum has a power-law index {gamma} = 1.02 {+-} 0.15 consistent with an accreting black hole in a steep power-law state. When compared to previous studies of NGC 300 X-1 performed with XMM-Newton, we find the source at the low end of the previously measured 0.3-10 keV luminosity. The spectrum of NGC 300 X-1 is dominated by a power law ({Gamma} = 2.0 {+-} 0.3) with amore » contribution at low energies by a thermal component. We estimate the 0.3-10 keV luminosity to be 2.6{sup +0.8}{sub -1.0} Multiplication-Sign 10{sup 38} erg s{sup -1}. The timing and spectroscopic properties of NGC 300 X-1 are consistent with being in a steep power-law state, similar to earlier observations performed with XMM-Newton. We additionally compare our observations to known high-mass X-ray binaries and ultraluminous X-ray sources, and find the properties of NGC 300 X-1 are most consistent with black hole high-mass X-ray binaries.« less

Central Engine Memory of Gamma-Ray Bursts and Soft Gamma-Ray Repeaters

NASA Astrophysics Data System (ADS)

Zhang, Bin-Bin; Zhang, Bing; Castro-Tirado, Alberto J.

2016-04-01

Gamma-ray bursts (GRBs) are bursts of γ-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that the central engine of at least some GRBs carries “memory” of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in soft gamma-ray repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, and suggest a common physical mechanism behind GRBs and SGRs, which points toward a magnetar central engine of GRBs.

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.

Compact Binary Progenitors of Short Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Giacomazzo, Bruno; Perna, Rosalba; Rezzolla, Luciano; Troja, Eleonora; Lazzati, Davide

2013-01-01

In recent years, detailed observations and accurate numerical simulations have provided support to the idea that mergers of compact binaries containing either two neutron stars (NSs) or an NS and a black hole (BH) may constitute the central engine of short gamma-ray bursts (SGRBs). The merger of such compact binaries is expected to lead to the production of a spinning BH surrounded by an accreting torus. Several mechanisms can extract energy from this system and power the SGRBs. Here we connect observations and numerical simulations of compact binary mergers, and use the current sample of SGRBs with measured energies to constrain the mass of their powering tori. By comparing the masses of the tori with the results of fully general-relativistic simulations, we are able to infer the properties of the binary progenitors that yield SGRBs. By assuming a constant efficiency in converting torus mass into jet energy epsilon(sub jet) = 10%, we find that most of the tori have masses smaller than 0.01 Solar M, favoring "high-mass" binary NSs mergers, i.e., binaries with total masses approx >1.5 the maximum mass of an isolated NS. This has important consequences for the gravitational wave signals that may be detected in association with SGRBs, since "high-mass" systems do not form a long-lived hypermassive NS after the merger. While NS-BH systems cannot be excluded to be the engine of at least some of the SGRBs, the BH would need to have an initial spin of approx. 0.9 or higher.

High-Mass Stars in the Centers of Young Dense Clusters: Mass Segregation, Binary Mergers and Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Zinnecker, H.

We start by discussing dense, young star-clusters, particularly the 30 Doradus cluster with its core R136. The question of mass segregation and core collapse of the massive stars is addressed. Analytical estimates of relaxation times and collision times predict that the central N=10 subsystem of massive stars in the R136 core will evolve dynamically in such a way and fast enough (i.e. within their main-sequence lifetime of a few Myr) that a dominant massive binary system is formed whose orbit will shrink to a point where merging of the components appears inevitable. The merger product will be spinning rapidly, and we put forward the idea that this rare and very massive object might be the perfect precursor of a gamma-ray burst (collapsar).

An interpretation of the narrow positron annihilation feature from X-ray nova Muscae 1991

NASA Technical Reports Server (NTRS)

Chen, Wan; Gehrels, Neil; Cheng, F. H.

1993-01-01

The physical mechanism responsible for the narrow redshifted positron annihilation gamma-ray line from the X-ray nova Muscae 1991 is studied. The orbital inclination angle of the system is estimated and its black hole mass is constrained under the assumptions that the annihilation line centroid redshift is purely gravitational and that the line width is due to the combined effect of temperature broadening and disk rotation. The large black hole mass lower limit of 8 solar and the high binary mass ratio it implies raise a serious challenge to theoretical models of the formation and evolution of massive binaries.

Time dependent radiation spectra from jets of microquasars

NASA Astrophysics Data System (ADS)

Gupta, Swati

X-ray binary systems in our galaxy exhibiting relativistic jets (microquasars) present one of the most recent additions to the field of high energy astrophysics. Jet models of high energy emission from these sources have created significant interest lately with detailed spectral and timing studies of the X-ray emission from microquasars, and their recent establishment as a new distinctive class of g-ray emitting sources after the detection of very - high-energy (VHE) g-rays from the microquasars LS 5039 and LS I +61° 303. This dissertation presents a study of radiation signatures from a leptonic jet model, based on time-dependent electron injection and acceleration, followed by their subsequent adiabatic and radiative cooling. The radiation mechanisms included are synchrotron, synchrotron self Compton and external Compton with soft photons provided by the companion star and the accretion disk. Compton scattering is treated both in the Thomson and the Klein-Nishina regimes, thus making the model applicable to microquasars that are candidates for VHE g-ray emission as well. An analytical solution to the electron kinetic equation is introduced for the Thomson regime treatment, while a numerical approach is adopted for the Klein-Nishina regime. Predictions regarding rapid flux and spectral variability signatures in the form of spectral hysteresis in the X-ray hardness intensity diagrams are made, which should be testable with monitoring observations using Chandra and/or XMM - Newton . Detections of such variability would help in distinguishing between various competing models for the high energy emission from these sources. Our results show that the shape and orientation of the hysteresis loops would allow identification of the dominant emission components as well as quantify physical parameters like the magnetic field, spectral index, Doppler boosting factor etc. The model is applied to available broadband observations of the two microquasars that have been very recently detected in VHE g-rays, namely LSI +61° 303 and LS 5039. In the case of LS I +61° 303, we explain the observed orbital modulation of the VHE g-ray emission solely by the geometrical effect of changes in the relative orientation of the stellar companion with respect to the compact object affecting the position and depth of the gg absorption trough. For LS 5039, our results imply that an orbital modulation of the velocity of the stellar wind in addition to gg absorption effects may be necessary to explain the orbital variability of the VHE g-ray emission.

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

Jenke, P. A.; Linares, M.; Connaughton, V.

The Fermi Gamma-ray Burst Monitor (GBM) is an all-sky gamma-ray monitor well known in the gamma-ray burst (GRB) community. Although GBM excels in detecting the hard, bright extragalactic GRBs, its sensitivity above 8 keV and its all-sky view make it an excellent instrument for the detection of rare, short-lived Galactic transients. In 2010 March, we initiated a systematic search for transients using GBM data. We conclude this phase of the search by presenting a three-year catalog of 1084 X-ray bursts. Using spectral analysis, location, and spatial distributions we classified the 1084 events into 752 thermonuclear X-ray bursts, 267 transient eventsmore » from accretion flares and X-ray pulses, and 65 untriggered gamma-ray bursts. All thermonuclear bursts have peak blackbody temperatures broadly consistent with photospheric radius expansion (PRE) bursts. We find an average rate of 1.4 PRE bursts per day, integrated over all Galactic bursters within about 10 kpc. These include 33 and 10 bursts from the ultra-compact X-ray binaries 4U 0614+09 and 2S 0918-549, respectively. We discuss these recurrence times and estimate the total mass ejected by PRE bursts in our Galaxy.« less

The afterglow of GRB 050709 and the nature of the short-hard gamma-ray bursts.

PubMed

Fox, D B; Frail, D A; Price, P A; Kulkarni, S R; Berger, E; Piran, T; Soderberg, A M; Cenko, S B; Cameron, P B; Gal-Yam, A; Kasliwal, M M; Moon, D-S; Harrison, F A; Nakar, E; Schmidt, B P; Penprase, B; Chevalier, R A; Kumar, P; Roth, K; Watson, D; Lee, B L; Shectman, S; Phillips, M M; Roth, M; McCarthy, P J; Rauch, M; Cowie, L; Peterson, B A; Rich, J; Kawai, N; Aoki, K; Kosugi, G; Totani, T; Park, H-S; MacFadyen, A; Hurley, K C

2005-10-06

The final chapter in the long-standing mystery of the gamma-ray bursts (GRBs) centres on the origin of the short-hard class of bursts, which are suspected on theoretical grounds to result from the coalescence of neutron-star or black-hole binary systems. Numerous searches for the afterglows of short-hard bursts have been made, galvanized by the revolution in our understanding of long-duration GRBs that followed the discovery in 1997 of their broadband (X-ray, optical and radio) afterglow emission. Here we present the discovery of the X-ray afterglow of a short-hard burst, GRB 050709, whose accurate position allows us to associate it unambiguously with a star-forming galaxy at redshift z = 0.160, and whose optical lightcurve definitively excludes a supernova association. Together with results from three other recent short-hard bursts, this suggests that short-hard bursts release much less energy than the long-duration GRBs. Models requiring young stellar populations, such as magnetars and collapsars, are ruled out, while coalescing degenerate binaries remain the most promising progenitor candidates.

Neutrinos from colliding wind binaries: future prospects for PINGU and ORCA

NASA Astrophysics Data System (ADS)

Becker Tjus, J.

2014-05-01

Massive stars play an important role in explaining the cosmic ray spectrum below the knee, possibly even up to the ankle, i.e. up to energies of 1015 or 1018.5 eV, respectively. In particular, Supernova Remnants are discussed as one of the main candidates to explain the cosmic ray spectrum. Even before their violent deaths, during the stars' regular life times, cosmic rays can be accelerated in wind environments. High-energy gamma-ray measurements indicate hadronic acceleration binary systems, leading to both periodic gamma-ray emission from binaries like LSI + 60 303 and continuous emission from colliding wind environments like η-Carinae. The detection of neutrinos and photons from hadronic interactions are one of the most promising methods to identify particle acceleration sites. In this paper, future prospects to detect neutrinos from colliding wind environments in massive stars are investigated. In particular, the seven most promising candidates for emission from colliding wind binaries are investigated to provide an estimate of the signal strength. The expected signal of a single source is about a factor of 5-10 below the current IceCube sensitivity and it is therefore not accessible at the moment. What is discussed in addition is future the possibility to measure low-energy neutrino sources with detectors like PINGU and ORCA: the minimum of the atmospheric neutrino flux at around 25 GeV from neutrino oscillations provides an opportunity to reduce the background and increase the significance to searches for GeV-TeV neutrino sources. This paper presents the first idea, detailed studies including the detector's effective areas will be necessary in the future to test the feasibility of such an approach.

Wind accretion in the massive X-ray binary 4U 2206+54: abnormally slow wind and a moderately eccentric orbit

NASA Astrophysics Data System (ADS)

Ribó, M.; Negueruela, I.; Blay, P.; Torrejón, J. M.; Reig, P.

2006-04-01

Massive X-ray binaries are usually classified by the properties of the donor star in classical, supergiant and Be X-ray binaries, the main difference being the mass transfer mechanism between the two components. The massive X-ray binary 4U 2206+54 does not fit in any of these groups, and deserves a detailed study to understand how the transfer of matter and the accretion on to the compact object take place. To this end we study an IUE spectrum of the donor and obtain a wind terminal velocity (v_∞) of ~350 km s-1, which is abnormally slow for its spectral type. We also analyse here more than 9 years of available RXTE/ASM data. We study the long-term X-ray variability of the source and find it to be similar to that observed in the wind-fed supergiant system Vela X-1, reinforcing the idea that 4U 2206+54 is also a wind-fed system. We find a quasi-period decreasing from ~270 to ~130 d, noticed in previous works but never studied in detail. We discuss possible scenarios for its origin and conclude that long-term quasi-periodic variations in the mass-loss rate of the primary are probably driving such variability in the measured X-ray flux. We obtain an improved orbital period of P_orb=9.5591±0.0007 d with maximum X-ray flux at MJD 51856.6±0.1. Our study of the orbital X-ray variability in the context of wind accretion suggests a moderate eccentricity around 0.15 for this binary system. Moreover, the low value of v_∞ solves the long-standing problem of the relatively high X-ray luminosity for the unevolved nature of the donor, BD +53°2790, which is probably an O9.5 V star. We note that changes in v_∞ and/or the mass-loss rate of the primary alone cannot explain the different patterns displayed by the orbital X-ray variability. We finally emphasize that 4U 2206+54, together with LS 5039, could be part of a new population of wind-fed HMXBs with main sequence donors, the natural progenitors of supergiant X-ray binaries.

An Argument for Weakly Magnetized, Slowly Rotating Progenitors of Long Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Moreno Méndez, Enrique

2014-01-01

Using binary evolution with Case-C mass transfer, the spins of several black holes (BHs) in X-ray binaries (XBs) have been predicted and confirmed (three cases) by observations. The rotational energy of these BHs is sufficient to power up long gamma-ray bursts (GRBs) and hypernovae (HNe) and still leave a Kerr BH behind. However, strong magnetic fields and/or dynamo effects in the interior of such stars deplete their cores from angular momentum preventing the formation of collapsars. Thus, even though binaries can produce Kerr BHs, most of their rotation is acquired from the stellar mantle, with a long delay between BH formation and spin up. Such binaries would not form GRBs. We study whether the conditions required to produce GRBs can be met by the progenitors of such BHs. Tidal-synchronization and Alfvén timescales are compared for magnetic fields of different intensities threading He stars. A search is made for a magnetic field range that allows tidal spin up all the way in to the stellar core but prevents its slow down during differential rotation phases. The energetics for producing a strong magnetic field during core collapse, which may allow for a GRB central engine, are also estimated. An observationally reasonable choice of parameters is found (B <~ 102 G threading a slowly rotating He star) that allows Fe cores to retain substantial angular momentum. Thus, the Case-C mass-transfer binary channel is capable of explaining long GRBs. However, the progenitors must have low initial spin and low internal magnetic field throughout their H-burning and He-burning phases.

First NICER Observations of the Enigmatic Be Star, Gamma Cassiopeiae

NASA Astrophysics Data System (ADS)

Hamaguchi, Kenji; Drake, Stephen; Corcoran, Michael; Gendreau, Keith C.; Steiner, Jack; NICER team

2018-01-01

Gamma Cassiopeiae is an enigmatic Be star with unusually hard, strong X-ray emission compared with normal main-sequence B stars (but a much lower X-ray luminosity than the classic X-ray binaries). The X-ray characteristics - hot (kT ~12 keV), thermal plasma spectrum and rapid time variations on timescales of 10-1000 sec - is reminiscent of accreting compact objects. Alternatively, its shot-like rapid variations somewhat resemble solar-type magnetic reconnection flares, so that plasma heating by the star-disk magnetic dynamo of the Be star has been proposed. A recent discovery of rapid X-ray color variations with the Suzaku X-ray observatory revealed the presence of rapidly moving absorbers in the X-ray line of sight, giving a strong constraint on the geometry of the X-ray emitting regions and absorbers.The X-ray observatory onboard ISS, NICER, has observed Gamma Cas multiple times. The large collecting area in the 0.3-10 keV band, tolerance to photon pile-ups, and decent energy resolution in particular below 1 keV, should provide excellent pieces of information on how the X-ray emission and/or absorbing column change on short timescales. We will present the first result of the gamma Cas observations made by the NICER observatory.

High energy neutrino absorption and its effects on stars in close X-ray binaries

NASA Technical Reports Server (NTRS)

Gaisser, T. K.; Stecker, F. W.

1986-01-01

The physics and astrophysics of high energy neutrino production and interactions in close X-ray binary systems are studied. These studies were stimulated by recent observations of ultrahigh energy gamma-rays and possibly other ultrahigh energy particles coming from the directions of Cygnus X-3 and other binary systems and possessing the periodicity characteristics of these systems. Systems in which a compact object, such as a neutron star, is a strong source of high energy particles which, in turn, produce photons, neutronos and other secondary particles by interactions in the atmosphere of the companion star were considered. The highest energy neutrinos are absorbed deep in the companion and the associated energy deposition may be large enough to effect its structure or lead to its ultimate disruption. This neutrino heating was evaluated, starting with a detailed numerical calculation of the hadronic cascade induced in the atmosphere of the companion star. For some theoretical models, the resulting energy deposition from neutrino absorption may be so great as to disrupt the companion star over an astronomically small timescale of the order of 10,000 years. Even if the energy deposition is smaller, it may still be high enough to alter the system substantially, perhaps leading to quenching of high energy signals from the source. Given the cosmic ray luminosities required to produce the observed gamma rays from cygnus X-3 and LMX X-4, such a situation may occur in these sources.

LFsGRB: Binary neutron star merger rate via the luminosity function of short gamma-ray bursts

NASA Astrophysics Data System (ADS)

Paul, Debdutta

2018-04-01

LFsGRB models the luminosity function (LF) of short Gamma Ray Bursts (sGRBs) by using the available catalog data of all short GRBs (sGRBs) detected till 2017 October, estimating the luminosities via pseudo-redshifts obtained from the Yonetoku correlation, and then assuming a standard delay distribution between the cosmic star formation rate and the production rate of their progenitors. The data are fit well both by exponential cutoff powerlaw and broken powerlaw models. Using the derived parameters of these models along with conservative values in the jet opening angles seen from afterglow observations, the true rate of short GRBs is derived. Assuming a short GRB is produced from each binary neutron star merger (BNSM), the rate of gravitational wave (GW) detections from these mergers are derived for the past, present and future configurations of the GW detector networks.

Mildly Recycled Pulsars at High-Energies

NASA Astrophysics Data System (ADS)

Pellizzoni, A.

2011-08-01

Mildly recyled pulsars (MRP), conventionally defined as neutron star having spin period in the 20-100 ms range and surface magnetic field <1011 Gauss, probably rise from binary systems (disrupted or not) with an intermediate or an high mass companion. Despite their relatively low spin-down energies compared to the ``fully'' recycled millisecond pulsars (arising from common low mass X-ray binaries), nearby MRPs can be detected by deep X-ray observations and by timing analysis of the very long data span provided by gamma-ray space detectors. The discovery of peculiar timing and spectral properties, possibly transitional, of the MRPs can be of the utmost importance to link different classes of neutron stars and study their evolution.

Short-Duration Gamma-Ray Burst in the Multi-Messenger Era

NASA Astrophysics Data System (ADS)

Lazzati, Davide

2016-12-01

The detection of gravitational waves (GW) from binary black hole mergers has been an historical, transformative event in physics and astronomy, heralded by most as the beginning of multi-messenger astronomy. With the increase of sensitivity over the next few years, LIGO and Virgo are predicted to detect mergers from neutron-star (NS) binaries. These are expected to be the first true multi-messenger sources, being the progenitors of short-duration gamma-ray burst (SGRB). The simultaneous detection of a gravitational, electromagnetic, and possibly neutrino signals from the same source would dramatically enhance the scientific output of each individual detection. Important details of the connection between SGRBs and NS binary mergers are however poorly known. These include the nature of the merging compact objects, their equation of state, the physics of SGRB jets - such as their Lorentz factors and opening angles, and the possibility of small temporal delays among the GW, n! eutrino, and gamma-ray signals. In view of the expected increased sensitivity of LIGO during the upcoming observing period and beyond, there is urgent need of improving our understanding of the physics of SGRBs to support the detection of GWs (and possibly neutrinos) and to develop a context in which the expected multi-messenger signal can be properly interpreted and its potential fully exploited. To achieve such goals, we propose to carry out a comprehensive study of relativistic jets from compact binary mergers, exploiting the most recent advances in numerical techniques developed within this research group. The ansatz of this study will be that within a short time after a compact merger a relativistic jet is created. Subsequently, the jet interacts with the merger environment, imprinting a signature that can be detected in the temporal and spectral properties of the prompt radiation, both in its electromagnetic and neutrino components. Analogous dynamical effects have been observed and studied extensively for long-duration GRBs. Since different progenitors produce different environments and physical conditions, the properties of the gamma-ray and neutrino signals will be a proxy to the physics of the merger and, ultimately, to the expected GW signal. We will perform a combination of state-of-the-art numerical simulations covering all different phases of the event,! including the coalescence and merger of the progenitor compact binary system, the small to large scale jet dynamics, and the radiation transfer physics leading to electromagnetic and neutrino signals. Our products will include multi messenger predictions not only for on-axis bursts, those pointing directly at earth, but also for off-axis events, those with jets that point away from our detectors. Off-axis bursts are expected to have a dim electromagnetic signature but they constitute the dominant population of LIGO detected NS binary mergers.

Fermi/LAT detection of a transient gamma-ray flare in the vicinity of the binary star DG CVn

DOE PAGES

Loh, Alan; Corbel, Stéphane; Dubus, Guillaume

2017-02-16

Solar flares are regularly detected by the Large Area Telescope (LAT) on board the Fermi satellite, however no γ-ray emission from other stellar eruptions has ever been captured. The Swift detection in 2014 April of a powerful outburst originating from DG CVn, with associated optical and radio emissions, enticed us to search for possible 0.1–100 GeV emission from this flaring nearby binary star using the Fermi/LAT. No γ-ray emission is detected from DG CVn in 2014, but we report a significant γ-ray excess in 2012 November, at a position consistent with that of the binary. There are no reports ofmore » contemporary flaring at other wavelengths from DG CVn or any other source within the error circle of the γ-ray source. As a result, we argue that the γ-ray flare is more likely to have been associated with a background blazar than with DG CVn and identify a candidate for follow-up study.« less

The Discovery of the Electromagnetic Counterpart of GW170817: Kilonova AT 2017gfo/DLT17ck

NASA Astrophysics Data System (ADS)

Valenti, Stefano; David; Sand, J.; Yang, Sheng; Cappellaro, Enrico; Tartaglia, Leonardo; Corsi, Alessandra; Jha, Saurabh W.; Reichart, Daniel E.; Haislip, Joshua; Kouprianov, Vladimir

2017-10-01

During the second observing run of the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo Interferometer, a gravitational-wave signal consistent with a binary neutron star coalescence was detected on 2017 August 17th (GW170817), quickly followed by a coincident short gamma-ray burst trigger detected by the Fermi satellite. The Distance Less Than 40 (DLT40) Mpc supernova search performed pointed follow-up observations of a sample of galaxies regularly monitored by the survey that fell within the combined LIGO+Virgo localization region and the larger Fermi gamma-ray burst error box. Here we report the discovery of a new optical transient (DLT17ck, also known as SSS17a; it has also been registered as AT 2017gfo) spatially and temporally coincident with GW170817. The photometric and spectroscopic evolution of DLT17ck is unique, with an absolute peak magnitude of M r = -15.8 ± 0.1 and an r-band decline rate of 1.1 mag day-1. This fast evolution is generically consistent with kilonova models, which have been predicted as the optical counterpart to binary neutron star coalescences. Analysis of archival DLT40 data does not show any sign of transient activity at the location of DLT17ck down to r ˜ 19 mag in the time period between 8 months and 21 days prior to GW170817. This discovery represents the beginning of a new era for multi-messenger astronomy, opening a new path by which to study and understand binary neutron star coalescences, short gamma-ray bursts, and their optical counterparts.

CENTRAL ENGINE MEMORY OF GAMMA-RAY BURSTS AND SOFT GAMMA-RAY REPEATERS

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

Zhang, Bin-Bin; Castro-Tirado, Alberto J.; Zhang, Bing, E-mail: zhang.grb@gmail.com

Gamma-ray bursts (GRBs) are bursts of γ-rays generated from relativistic jets launched from catastrophic events such as massive star core collapse or binary compact star coalescence. Previous studies suggested that GRB emission is erratic, with no noticeable memory in the central engine. Here we report a discovery that similar light curve patterns exist within individual bursts for at least some GRBs. Applying the Dynamic Time Warping method, we show that similarity of light curve patterns between pulses of a single burst or between the light curves of a GRB and its X-ray flare can be identified. This suggests that themore » central engine of at least some GRBs carries “memory” of its activities. We also show that the same technique can identify memory-like emission episodes in the flaring emission in soft gamma-ray repeaters (SGRs), which are believed to be Galactic, highly magnetized neutron stars named magnetars. Such a phenomenon challenges the standard black hole central engine models for GRBs, and suggest a common physical mechanism behind GRBs and SGRs, which points toward a magnetar central engine of GRBs.« less

High-energy Neutrino Emission from Short Gamma-Ray Bursts: Prospects for Coincident Detection with Gravitational Waves

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

Kimura, Shigeo S.; Murase, Kohta; Mészáros, Peter

We investigate current and future prospects for coincident detection of high-energy neutrinos and gravitational waves (GWs). Short gamma-ray bursts (SGRBs) are believed to originate from mergers of compact star binaries involving neutron stars. We estimate high-energy neutrino fluences from prompt emission, extended emission (EE), X-ray flares, and plateau emission, and we show that neutrino signals associated with the EE are the most promising. Assuming that the cosmic-ray loading factor is ∼10 and the Lorentz factor distribution is lognormal, we calculate the probability of neutrino detection from EE by current and future neutrino detectors, and we find that the quasi-simultaneous detectionmore » of high-energy neutrinos, gamma-rays, and GWs is possible with future instruments or even with current instruments for nearby SGRBs having EE. We also discuss stacking analyses that will also be useful with future experiments such as IceCube-Gen2.« less

All-Sky Earth Occultation Observations with the Fermi Gamma Ray Burst Monitor

NASA Technical Reports Server (NTRS)

Wilson-Hodge, C. A.; Beklen, E.; Bhat, P. N.; Briggs, M.; Camero-Arranz, A.; Case, G.; Chaplin, V.; Cherry, M.; Connaughton, V.; Finger, M.;

High Energy Follow-up Study of Gravitational Wave Transients

NASA Astrophysics Data System (ADS)

Barker, Brandon L.; Patricelli, Barbara

2018-01-01

As second-generation gravitational wave interferometers, such as Advanced Virgo and Advanced LIGO, reach their design sensitivities, a new lens into our universe will become available. Many of the most violent and energetic events in the cosmos, in particular the merger of compact objects and core collapse supernovae, are sources of gravitational waves and are also believed to be connected with Gamma Ray Bursts. Joint observations of electromagnetic and gravitational wave signals will provide an ideal opportunity to study the physics of these transient events and their progenitors. In particular, gamma ray observatories such as Fermi, coupled with precise sky lo- calization, will be crucial to observe the high energy electromagnetic counterparts to gravitational wave signals. We constructed joint binary neutron star and gamma ray burst detection rate estimates using an analysis pipeline and report on the results of this analysis.

X ray and gamma ray emission from classical nova outbursts

NASA Technical Reports Server (NTRS)

Truran, James W.; Starrfield, Sumner; Sparks, Warren M.

1992-01-01

The outbursts of classical novae are now recognized to be consequences of thermonuclear runaways proceeding in accreted hydrogen-rich shells on white dwarfs in close binary systems. For the conditions that are known to exist in these environments, it is expected that soft x-rays can be emitted, and indeed x-rays were detected from a number of novae. The circumstances for which we expect novae to produce significant x-ray fluxes and provide estimates of the luminosities and effective temperatures are described. It is also known that at the high temperatures that are known to be achieved in this explosive hydrogen-burning environment, significant production of both Na-22 and Al-26 will occur. In this context, we identify the conditions for which gamma-ray emission may be expected to result from nova outbursts.

IGR J19294+1816: a new Be-X-ray binary revealed through infrared spectroscopy

NASA Astrophysics Data System (ADS)

Rodes-Roca, J. J.; Bernabeu, G.; Magazzù, A.; Torrejón, J. M.; Solano, E.

2018-05-01

The aim of this work is to characterize the counterpart to the INTErnational Gamma-Ray Astrophysics Laboratory high-mass X-ray binary candidate IGR J19294+1816 so as to establish its true nature. We obtained H-band spectra of the selected counterpart acquired with the Near Infrared Camera and Spectrograph instrument mounted on the Telescopio Nazionale Galileo 3.5-m telescope which represents the first infrared spectrum ever taken of this source. We complement the spectral analysis with infrared photometry from UKIDSS, 2MASS, WISE, and NEOWISE data bases. We classify the mass donor as a Be star. Subsequently, we compute its distance by properly taking into account the contamination produced by the circumstellar envelope. The findings indicate that IGR J19294+1816 is a transient source with a B1Ve donor at a distance of d = 11 ± 1 kpc, and luminosities of the order of 1036-37 erg s-1, displaying the typical behaviour of a Be-X-ray binary.

Constraints on particle acceleration in SS433/W50 from MAGIC and H.E.S.S. observations

NASA Astrophysics Data System (ADS)

MAGIC Collaboration; Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Borracci, F.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Lotto, B.; de Oña Wilhelmi, E.; di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Griffiths, S.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Hughes, G.; Ishio, K.; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; López-Oramas, A.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Minev, M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Munar-Adrover, P.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Torres-Albà, N.; Treves, A.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Wu, M. H.; Zarić, D.; H.E.S.S. Collaboration; Abdalla, H.; Abramowski, A.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Andersson, T.; Angüner, E. O.; Arakawa, M.; Arrieta, M.; Aubert, P.; Backes, M.; Balzer, A.; Barnard, M.; Becherini, Y.; Becker Tjus, J.; Berge, D.; Bernhard, S.; Bernlöhr, K.; Blackwell, R.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Bregeon, J.; Brun, F.; Brun, P.; Bryan, M.; Büchele, M.; Bulik, T.; Capasso, M.; Carr, J.; Casanova, S.; Cerruti, M.; Chakraborty, N.; Chalme-Calvet, R.; Chaves, R. C. G.; Chen, A.; Chevalier, J.; Chrétien, M.; Coffaro, M.; Colafrancesco, S.; Cologna, G.; Condon, B.; Conrad, J.; Cui, Y.; Davids, I. D.; Decock, J.; Degrange, B.; Deil, C.; Devin, J.; Dewilt, P.; Dirson, L.; Djannati-Ataï, A.; Domainko, W.; Donath, A.; Drury, L. O.'c.; Dutson, K.; Dyks, J.; Edwards, T.; Egberts, K.; Eger, P.; Ernenwein, J.-P.; Eschbach, S.; Farnier, C.; Fegan, S.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Funk, S.; Füßling, M.; Gabici, S.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Gottschall, D.; Goyal, A.; Grondin, M.-H.; Hahn, J.; Haupt, M.; Hawkes, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hinton, J. A.; Hofmann, W.; Hoischen, C.; Holler, M.; Horns, D.; Ivascenko, A.; Iwasaki, H.; Jacholkowska, A.; Jamrozy, M.; Janiak, M.; Jankowsky, D.; Jankowsky, F.; Jingo, M.; Jogler, T.; Jouvin, L.; Jung-Richardt, I.; Kastendieck, M. A.; Katarzyński, K.; Katsuragawa, M.; Katz, U.; Kerszberg, D.; Khangulyan, D.; Khélifi, B.; Kieffer, M.; King, J.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Kraus, M.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lau, J.; Lees, J.-P.; Lefaucheur, J.; Lefranc, V.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Leser, E.; Lohse, T.; Lorentz, M.; Liu, R.; López-Coto, R.; Lypova, I.; Marandon, V.; Marcowith, A.; Mariaud, C.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; Meintjes, P. J.; Meyer, M.; Mitchell, A. M. W.; Moderski, R.; Mohamed, M.; Mohrmann, L.; Morå, K.; Moulin, E.; Murach, T.; Nakashima, S.; de Naurois, M.; Niederwanger, F.; Niemiec, J.; Oakes, L.; O'Brien, P.; Odaka, H.; Öttl, S.; Ohm, S.; Ostrowski, M.; Oya, I.; Padovani, M.; Panter, M.; Parsons, R. D.; Pekeur, N. W.; Pelletier, G.; Perennes, C.; Petrucci, P.-O.; Peyaud, B.; Piel, Q.; Pita, S.; Poon, H.; Prokhorov, D.; Prokoph, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Reimer, A.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Richter, S.; Rieger, F.; Romoli, C.; Rowell, G.; Rudak, B.; Rulten, C. B.; Safi-Harb, S.; Sahakian, V.; Saito, S.; Salek, D.; Sanchez, D. A.; Santangelo, A.; Sasaki, M.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwemmer, S.; Seglar-Arroyo, M.; Settimo, M.; Seyffert, A. S.; Shafi, N.; Shilon, I.; Simoni, R.; Sol, H.; Spanier, F.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stycz, K.; Sushch, I.; Takahashi, T.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tibaldo, L.; Tiziani, D.; Tluczykont, M.; Trichard, C.; Tsuji, N.; Tuffs, R.; Uchiyama, Y.; van der Walt, D. J.; van Eldik, C.; van Rensburg, C.; van Soelen, B.; Vasileiadis, G.; Veh, J.; Venter, C.; Viana, A.; Vincent, P.; Vink, J.; Voisin, F.; Völk, H. J.; Vuillaume, T.; Wadiasingh, Z.; Wagner, S. J.; Wagner, P.; Wagner, R. M.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Yang, R.; Zabalza, V.; Zaborov, D.; Zacharias, M.; Zanin, R.; Zdziarski, A. A.; Zech, A.; Zefi, F.; Ziegler, A.; Zywucka, N.

2018-04-01

Context. The large jet kinetic power and non-thermal processes occurring in the microquasar SS 433 make this source a good candidate for a very high-energy (VHE) gamma-ray emitter. Gamma-ray fluxes above the sensitivity limits of current Cherenkov telescopes have been predicted for both the central X-ray binary system and the interaction regions of SS 433 jets with the surrounding W50 nebula. Non-thermal emission at lower energies has been previously reported, indicating that efficient particle acceleration is taking place in the system. Aim. We explore the capability of SS 433 to emit VHE gamma rays during periods in which the expected flux attenuation due to periodic eclipses (Porb 13.1 days) and precession of the circumstellar disk (Ppre 162 days) periodically covering the central binary system is expected to be at its minimum. The eastern and western SS 433/W50 interaction regions are also examined using the whole data set available. We aim to constrain some theoretical models previously developed for this system with our observations. Methods: We made use of dedicated observations from the Major Atmospheric Gamma Imaging Cherenkov telescopes (MAGIC) and High Energy Spectroscopic System (H.E.S.S.) of SS 433 taken from 2006 to 2011. These observation were combined for the first time and accounted for a total effective observation time of 16.5 h, which were scheduled considering the expected phases of minimum absorption of the putative VHE emission. Gamma-ray attenuation does not affect the jet/medium interaction regions. In this case, the analysis of a larger data set amounting to 40-80 h, depending on the region, was employed. Results: No evidence of VHE gamma-ray emission either from the central binary system or from the eastern/western interaction regions was found. Upper limits were computed for the combined data set. Differential fluxes from the central system are found to be ≲ 10-12-10-13 TeV-1 cm-2 s-1 in an energy interval ranging from few × 100 GeV to few TeV. Integral flux limits down to 10-12-10-13 ph cm-2 s-1 and 10-13-10-14 ph cm-2 s-1 are obtainedat 300 and 800 GeV, respectively. Our results are used to place constraints on the particle acceleration fraction at the inner jetregions and on the physics of the jet/medium interactions. Conclusions: Our findings suggest that the fraction of the jet kinetic power that is transferred to relativistic protons must be relatively small in SS 433, qp ≤ 2.5 × 10-5, to explain the lack of TeV and neutrino emission from the central system. At the SS 433/W50 interface, the presence of magnetic fields ≳10 μG is derived assuming a synchrotron origin for the observed X-ray emission. This also implies the presence of high-energy electrons with Ee- up to 50 TeV, preventing an efficient production of gamma-ray fluxes in these interaction regions.

An argument for weakly magnetized, slowly rotating progenitors of long gamma-ray bursts

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

Moreno Méndez, Enrique, E-mail: enriquemm@astro.unam.mx

2014-01-20

Using binary evolution with Case-C mass transfer, the spins of several black holes (BHs) in X-ray binaries (XBs) have been predicted and confirmed (three cases) by observations. The rotational energy of these BHs is sufficient to power up long gamma-ray bursts (GRBs) and hypernovae (HNe) and still leave a Kerr BH behind. However, strong magnetic fields and/or dynamo effects in the interior of such stars deplete their cores from angular momentum preventing the formation of collapsars. Thus, even though binaries can produce Kerr BHs, most of their rotation is acquired from the stellar mantle, with a long delay between BHmore » formation and spin up. Such binaries would not form GRBs. We study whether the conditions required to produce GRBs can be met by the progenitors of such BHs. Tidal-synchronization and Alfvén timescales are compared for magnetic fields of different intensities threading He stars. A search is made for a magnetic field range that allows tidal spin up all the way in to the stellar core but prevents its slow down during differential rotation phases. The energetics for producing a strong magnetic field during core collapse, which may allow for a GRB central engine, are also estimated. An observationally reasonable choice of parameters is found (B ≲ 10{sup 2} G threading a slowly rotating He star) that allows Fe cores to retain substantial angular momentum. Thus, the Case-C mass-transfer binary channel is capable of explaining long GRBs. However, the progenitors must have low initial spin and low internal magnetic field throughout their H-burning and He-burning phases.« less

Pulsar simulations for the Fermi Large Area Telescope

DOE PAGES

Razzano, M.; Harding, Alice K.; Baldini, L.; ...

2009-05-21

Pulsars are among the prime targets for the Large Area Telescope (LAT) aboard the recently launched Fermi observatory. The LAT will study the gamma-ray Universe between 20 MeV and 300 GeV with unprecedented detail. Increasing numbers of gamma-ray pulsars are being firmly identified, yet their emission mechanisms are far from being understood. To better investigate and exploit the LAT capabilities for pulsar science, a set of new detailed pulsar simulation tools have been developed within the LAT collaboration. The structure of the pulsar simulator package ( PulsarSpectrum) is presented here. Starting from photon distributions in energy and phase obtained frommore » theoretical calculations or phenomenological considerations, gamma-rays are generated and their arrival times at the spacecraft are determined by taking into account effects such as barycentric effects and timing noise. Pulsars in binary systems also can be simulated given orbital parameters. As a result, we present how simulations can be used for generating a realistic set of gamma-rays as observed by the LAT, focusing on some case studies that show the performance of the LAT for pulsar observations.« less

Is magnetar a fact or fiction to us?

NASA Astrophysics Data System (ADS)

Tong, H.; Xu, R. X.

2013-03-01

The key point of studying AXPs/SGRs (anomalous X-ray pulsars/soft gamma-ray repeaters) is relevant to the energy budget. Historically, rotation was thought to be the only free energy of pulsar until the discovery of accretion power in X-ray binaries. AXPs/SGRs could be magnetars if they are magnetism-powered, but would alternatively be quark-star/fallback-disk systems if more and more observations would hardly be understood in the magnetar scenario.

GRB070610: A Curious Galactic Transient

NASA Technical Reports Server (NTRS)

Kasliwal, M. M.; Kulkrarni. S. R.; Cameron, P. B.; Nakar, E.; Ofek, E. O.; Rau, A.; Soderberg, A. M.; Campana, S.; Bloom, J. S.; Perley, D. A.;

Off-axis emission of short γ-ray bursts and the detectability of electromagnetic counterparts of gravitational-wave-detected binary mergers

NASA Astrophysics Data System (ADS)

Lazzati, Davide; Deich, Alex; Morsony, Brian J.; Workman, Jared C.

2017-10-01

We present calculations of the wide angle emission of short-duration gamma-ray bursts from compact binary merger progenitors. Such events are expected to be localized by their gravitational wave emission, fairly irrespective of the orientation of the angular momentum vector of the system, along which the gamma-ray burst outflow is expected to propagate. We show that both the prompt and afterglow emission are dim and challenging to detect for observers lying outside the cone within which the relativistic outflow is propagating. If the jet initially propagates through a baryon contaminated region surrounding the merger site, however, a hot cocoon forms around it. The cocoon subsequently expands quasi-isotropically producing its own prompt emission and external shock powered afterglow. We show that the cocoon prompt emission is detectable by Swift BAT and Fermi GBM. We also show that the cocoon afterglow peaks a few hours to a few days after the burst and is detectable for up to a few weeks at all wavelengths. The timing and brightness of the transient are however uncertain due to their dependence on unknown quantities such as the density of the ambient medium surrounding the merger site, the cocoon energy and the cocoon Lorentz factor. For a significant fraction of the gravitationally detected neutron-star-binary mergers, the cocoon afterglow could possibly be the only identifiable electromagnetic counterpart, at least at radio and X-ray frequencies.

"Short, Hard Gamma-Ray Bursts - Mystery Solved?????"

NASA Technical Reports Server (NTRS)

Parsons, A.

2006-01-01

After over a decade of speculation about the nature of short-duration hard-spectrum gamma-ray bursts (GRBs), the recent detection of afterglow emission from a small number of short bursts has provided the first physical constraints on possible progenitor models. While the discovery of afterglow emission from long GRBs was a real breakthrough linking their origin to star forming galaxies, and hence the death of massive stars, the progenitors, energetics, and environments for short gamma-ray burst events remain elusive despite a few recent localizations. Thus far, the nature of the host galaxies measured indicates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions and providing support for coalescing compact object binaries as the progenitors. On the other hand, some of the short burst afterglow observations cannot be easily explained in the coalescence scenario. These observations raise the possibility that short GRBs may have different or multiple progenitors systems. The study of the short-hard GRB afterglows has been made possible by the Swift Gamma-ray Burst Explorer, launched in November of 2004. Swift is equipped with a coded aperture gamma-ray telescope that can observe up to 2 steradians of the sky and can compute the position of a gamma-ray burst to within 2-3 arcmin in less than 10 seconds. The Swift spacecraft can slew on to this burst position without human intervention, allowing its on-board x ray and optical telescopes to study the afterglow within 2 minutes of the original GRB trigger. More Swift short burst detections and afterglow measurements are needed before we can declare that the mystery of short gamma-ray burst is solved.

A NOVEL PARADIGM FOR SHORT GAMMA-RAY BURSTS WITH EXTENDED X-RAY EMISSION

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

Rezzolla, Luciano; Kumar, Pawan

2015-04-01

The merger of a binary of neutron stars provides natural explanations for many of the features of short gamma-ray bursts (SGRBs), such as the generation of a hot torus orbiting a rapidly rotating black hole, which can then build a magnetic jet and provide the energy reservoir to launch a relativistic outflow. However, this scenario has problems explaining the recently discovered long-term and sustained X-ray emission associated with the afterglows of a subclass of SGRBs. We propose a new model that explains how an X-ray afterglow can be sustained by the product of the merger and how the X-ray emissionmore » is produced before the corresponding emission in the gamma-band, though it is observed to follow it. Overall, our paradigm combines in a novel manner a number of well-established features of the emission in SGRBs and results from simulations. Because it involves the propagation of an ultra-relativistic outflow and its interaction with a confining medium, the paradigm also highlights a unifying phenomenology between short and long GRBs.« less

Overview of MAGIC results

NASA Astrophysics Data System (ADS)

Rico, Javier; MAGIC Collaboration

2016-04-01

MAGIC is a system of two 17-m diameter Cherenkov telescopes, located at the Observatorio del Roque de los Muchachos, in the Canary island La Palma (Spain). MAGIC performs astronomical observations of gamma-ray sources in the energy range between 50 GeV and 10 TeV. The first MAGIC telescope has been operating since 2004, and in 2009 the system was completed with the second one. During 2011 and 2012 the electronics for the readout system were fully upgraded, and the camera of the first telescope replaced. After that, no major hardware interventions are foreseen in the next years, and the experiment has undertaken a final period of steady astronomical observations. MAGIC studies particle acceleration in the most violent cosmic environments, such as active galactic nuclei, gamma-ray bursts, pulsars, supernova remnants or binary systems. In addition, it addresses some fundamental questions of Physics, such as the origin of Galactic cosmic rays and the nature of dark matter. Moreover, by observing the gamma-ray emission from sources at cosmological distances, we measure the intensity and evolution of the extragalactic background radiation, and perform tests of Lorentz Invariance. In this paper I present the status and some of the latest results of the MAGIC gamma-ray telescopes.

Insight-HXMT observations of the first binary neutron star merger GW170817

NASA Astrophysics Data System (ADS)

Li, TiPei; Xiong, ShaoLin; Zhang, ShuangNan; Lu, FangJun; Song, LiMing; Cao, XueLei; Chang, Zhi; Chen, Gang; Chen, Li; Chen, TianXiang; Chen, Yong; Chen, YiBao; Chen, YuPeng; Cui, Wei; Cui, WeiWei; Deng, JingKang; Dong, YongWei; Du, YuanYuan; Fu, MinXue; Gao, GuanHua; Gao, He; Gao, Min; Ge, MingYu; Gu, YuDong; Guan, Ju; Guo, ChengCheng; Han, DaWei; Hu, Wei; Huang, Yue; Huo, Jia; Jia, ShuMei; Jiang, LuHua; Jiang, WeiChun; Jin, Jing; Jin, YongJie; Li, Bing; Li, ChengKui; Li, Gang; Li, MaoShun; Li, Wei; Li, Xian; Li, XiaoBo; Li, XuFang; Li, YanGuo; Li, ZiJian; Li, ZhengWei; Liang, XiaoHua; Liao, JinYuan; Liu, CongZhan; Liu, GuoQing; Liu, HongWei; Liu, ShaoZhen; Liu, XiaoJing; Liu, Yuan; Liu, YiNong; Lu, Bo; Lu, XueFeng; Luo, Tao; Ma, Xiang; Meng, Bin; Nang, Yi; Nie, JianYin; Ou, Ge; Qu, JinLu; Sai, Na; Sun, Liang; Tan, Yin; Tao, Lian; Tao, WenHui; Tuo, YouLi; Wang, GuoFeng; Wang, HuanYu; Wang, Juan; Wang, WenShuai; Wang, YuSa; Wen, XiangYang; Wu, BoBing; Wu, Mei; Xiao, GuangCheng; Xu, He; Xu, YuPeng; Yan, LinLi; Yang, JiaWei; Yang, Sheng; Yang, YanJi; Zhang, AiMei; Zhang, ChunLei; Zhang, ChengMo; Zhang, Fan; Zhang, HongMei; Zhang, Juan; Zhang, Qiang; Zhang, Shu; Zhang, Tong; Zhang, Wei; Zhang, WanChang; Zhang, WenZhao; Zhang, Yi; Zhang, Yue; Zhang, YiFei; Zhang, YongJie; Zhang, Zhao; Zhang, ZiLiang; Zhao, HaiSheng; Zhao, JianLing; Zhao, XiaoFan; Zheng, ShiJie; Zhu, Yue; Zhu, YuXuan; Zou, ChangLin

2018-03-01

Finding the electromagnetic (EM) counterpart of binary compact star merger, especially the binary neutron star (BNS) merger, is critically important for gravitational wave (GW) astronomy, cosmology and fundamental physics. On Aug. 17, 2017, Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart, GRB 170817A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope (HE) onboard Insight-HXMT (Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart (SSS17a/AT2017gfo) with very large collection area ( 1000 cm2) and microsecond time resolution in 0.2-5 MeV. In addition, Insight-HXMT quickly implemented a Target of Opportunity (ToO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy (0.2-5 MeV) radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817A. Meanwhile, Insight-HXMT/HE provides one of the most stringent constraints ( 10‒7 to 10‒6 erg/cm2/s) for both GRB170817A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.

Cosmological gamma-ray bursts

NASA Technical Reports Server (NTRS)

Paczynski, Bohdan

1991-01-01

The distribution in angle and flux of gamma-ray bursts indicates that the majority of gamma-ray bursters are at cosmological distances, i.e., at z of about 1. The rate is then about 10 exp -8/yr in a galaxy like the Milky Way, i.e., orders of magnitude lower than the estimated rate for collisions between neutron stars in close binary systems. The energy per burst is about 10 exp 51 ergs, assuming isotropic emission. The events appear to be less energetic and more frequent if their emission is strongly beamed. Some tests for the distance scale are discussed: a correlation between the burst's strength and its spectrum; the absorption by the Galactic gas below about 2 keV; the X-ray tails caused by forward scattering by the Galactic dust; about 1 month recurrence of some bursts caused by gravitational lensing by foreground galaxies; and a search for gamma-ray bursts in M31. The bursts appear to be a manifestation of something exotic, but conventional compact objects can provide an explanation. The best possibility is offered by a decay of a bindary composed of a spinning-stellar-mass black-hole primary and a neutron or a strange-quark star secondary. In the final phase the secondary is tidally disrupted, forms an accretion disk, and up to 10 exp 54 ergs are released. A very small fraction of this energy powers the gamma-ray burst.

Preview of the BATSE Earth Occultation Catalog of Low Energy Gamma Ray Sources

NASA Technical Reports Server (NTRS)

Harmon, B. A.; Wilson, C. A.; Fishman, G. J.; McCollough, M. L.; Robinson, C. R.; Sahi, M.; Paciesas, W. S.; Zhang, S. N.

1999-01-01

The Burst and Transient Source Experiment (BATSE) aboard the Compton Gamma Ray Observatory (CGRO) has been detecting and monitoring point sources in the high energy sky since 1991. Although BATSE is best known for gamma ray bursts, it also monitors the sky for longer-lived sources of radiation. Using the Earth occultation technique to extract flux information, a catalog is being prepared of about 150 sources potential emission in the large area detectors (20-1000 keV). The catalog will contain light curves, representative spectra, and parametric data for black hole and neutron star binaries, active galaxies, and super-nova remnants. In this preview, we present light curves for persistent and transient sources, and also show examples of what type of information can be obtained from the BATSE Earth occultation database. Options for making the data easily accessible as an "on line" WWW document are being explored.

Gamma-ray Burst and Gravitational Wave Counterpart Prospects in the MeV Band with AMEGO

NASA Astrophysics Data System (ADS)

Racusin, Judith; AMEGO Team

2018-01-01

The All-sky Medium Energy Gamma-ray Observatory (AMEGO) Probe mission concept is uniquely suited to address open questions in Gamma-ray Burst (GRB) science including the search for counterparts to gravitational-wave events. AMEGO is a wide field of view instrument (~60 deg radius) with a broad energy range (~200 keV to >10 GeV) and excellent continuum sensitivity. The sensitivity improvement will allow for probes of GRB emission mechanisms and jet composition in ways that have not been accessible with previous instruments. Potential for polarization measurement may also have profound impacts on the understanding of GRB mechanisms. AMEGO will also be an excellent facility for the search for gravitational wave counterparts to binary mergers including at least one neutron star, which are thought to produce short duration GRBs. This poster will describe how the AMEGO will advance these fields.

Nature and evolution of the eclipsing millisecond binary pulsar PSR1957 + 20

NASA Technical Reports Server (NTRS)

Kluzniak, W.; Ruderman, M.; Shaham, J.; Tavani, M.

1988-01-01

A model in which a millisecond pulsar may be able to evaporate a very light companion by a particular component of its energetic radiation is applied to the recently discovered 1.6-ms pulsar PSR1957 + 20. Pulsar turn-on in the very low-mass X-ray binary follows a stage of mass transfer dominated by an evaporative wind from the surface of the companion. The wind is driven by a large MeV gamma-ray flux powered by an accretion dynamo. That source of radiation ceases when it is replaced by that from the millisecond pulsar, which has been spun up by accretion.

EGRET upper limits to the high-energy gamma-ray emission from the millisecond pulsars in nearby globular clusters

NASA Technical Reports Server (NTRS)

Michelson, P. F.; Bertsch, D. L.; Brazier, K.; Chiang, J.; Dingus, B. L.; Fichtel, C. E.; Fierro, J.; Hartman, R. C.; Hunter, S. D.; Kanbach, G.

1994-01-01

We report upper limits to the high-energy gamma-ray emission from the millisecond pulsars (MSPs) in a number of globular clusters. The observations were done as part of an all-sky survey by the energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (CGRO) during Phase I of the CGRO mission (1991 June to 1992 November). Several theoretical models suggest that MSPs may be sources of high-energy gamma radiation emitted either as primary radiation from the pulsar magnetosphere or as secondary radiation generated by conversion into photons of a substantial part of the relativistic e(+/-) pair wind expected to flow from the pulsar. To date, no high-energy emission has been detected from an individual MSP. However, a large number of MSPs are expected in globular cluster cores where the formation rate of accreting binary systems is high. Model predictions of the total number of pulsars range in the hundreds for some clusters. These expectations have been reinforced by recent discoveries of a substantial number of radio MSPs in several clusters; for example, 11 have been found in 47 Tucanae (Manchester et al.). The EGRET observations have been used to obtain upper limits for the efficiency eta of conversion of MSP spin-down power into hard gamma rays. The upper limits are also compared with the gamma-ray fluxes predicted from theoretical models of pulsar wind emission (Tavani). The EGRET limits put significant constraints on either the emission models or the number of pulsars in the globular clusters.

LOCALIZATION AND BROADBAND FOLLOW-UP OF THE GRAVITATIONAL-WAVE TRANSIENT GW150914

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

Abbott, B. P.; Abbott, R.; Abernathy, M. R.

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize themore » follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline, and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams.« less

Localization and Broadband Follow-up of the Gravitational-wave Transient 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.; Barthelmy, S.; 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. 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.; Bustillo, J. C.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Diaz, J. C.; Casentini, C.; Caudill, S.; Cavagliá, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Baiardi, L. C.; 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., Jr.; 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, A.; 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. G.; 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, N.; Kim, N.; 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, A.; 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, R. 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.; Palliyaguru, N.; 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, 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.; 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; Allison, J.; Bannister, K.; Bell, M. E.; Chatterjee, S.; Chippendale, A. P.; Edwards, P. G.; Harvey-Smith, L.; Heywood, Ian; Hotan, A.; Indermuehle, B.; Marvil, J.; McConnell, D.; Murphy, T.; Popping, A.; Reynolds, J.; Sault, R. J.; Voronkov, M. A.; Whiting, M. T.; Australian Square Kilometer Array Pathfinder (ASKAP Collaboration); Castro-Tirado, A. J.; Cunniffe, R.; Jelínek, M.; Tello, J. C.; Oates, S. R.; Hu, Y.-D.; Kubánek, P.; Guziy, S.; Castellón, A.; García-Cerezo, A.; Muñoz, V. F.; Pérez del Pulgar, C.; Castillo-Carrión, S.; Castro Cerón, J. M.; Hudec, R.; Caballero-García, M. D.; Páta, P.; Vitek, S.; Adame, J. A.; Konig, S.; Rendón, F.; Mateo Sanguino, T. de J.; Fernández-Muñoz, R.; Yock, P. C.; Rattenbury, N.; Allen, W. H.; Querel, R.; Jeong, S.; Park, I. H.; Bai, J.; Cui, Ch.; Fan, Y.; Wang, Ch.; Hiriart, D.; Lee, W. H.; Claret, A.; Sánchez-Ramírez, R.; Pandey, S. B.; Mediavilla, T.; Sabau-Graziati, L.; BOOTES Collaboration; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Armstrong, R.; Benoit-Lévy, A.; Berger, E.; Bernstein, R. A.; Bertin, E.; Brout, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carretero, J.; Castander, F. J.; Chornock, R.; Cowperthwaite, P. S.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doctor, Z.; Drlica-Wagner, A.; Drout, M. R.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Foley, R. J.; Fong, W.-F.; Fosalba, P.; Fox, D. B.; Frieman, J.; Fryer, C. L.; Gaztanaga, E.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Herner, K.; Honscheid, K.; James, D. J.; Johnson, M. D.; Johnson, M. W. G.; Karliner, I.; Kasen, D.; Kent, S.; Kessler, R.; Kim, A. G.; Kind, M. C.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Lin, H.; Maia, M. A. G.; Margutti, R.; Marriner, J.; Martini, P.; Matheson, T.; Melchior, P.; Metzger, B. D.; Miller, C. J.; Miquel, R.; Neilsen, E.; Nichol, R. C.; Nord, B.; Nugent, P.; Ogando, R.; Petravick, D.; Plazas, A. A.; Quataert, E.; Roe, N.; Romer, A. K.; Roodman, A.; Rosell, A. C.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Scolnic, D.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, N.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Stebbins, A.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Thomas, R. C.; Tucker, D. L.; Vikram, V.; Walker, A. R.; Wechsler, R. H.; Wester, W.; Yanny, B.; Zhang, Y.; Zuntz, J.; Dark Energy Survey Collaboration; Dark Energy Camera GW-EM Collaboration; Connaughton, V.; Burns, E.; Goldstein, A.; Briggs, M. S.; Zhang, B.-B.; Hui, C. M.; Jenke, P.; Wilson-Hodge, C. A.; Bhat, P. N.; Bissaldi, E.; Cleveland, W.; Fitzpatrick, G.; Giles, M. M.; Gibby, M. H.; Greiner, J.; von Kienlin, A.; Kippen, R. M.; McBreen, S.; Mailyan, B.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Roberts, O.; Sparke, L.; Stanbro, M.; Toelge, K.; Veres, P.; Yu, H.-F.; Blackburn, L.; Fermi GBM Collaboration; Ackermann, M.; Ajello, M.; Albert, A.; Anderson, B.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Bruel, P.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caragiulo, M.; Caraveo, P. A.; Cavazzuti, E.; Charles, E.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Cohen-Tanugi, J.; Cominsky, L. R.; Costanza, F.; Cuoco, A.; D'Ammando, F.; de Palma, F.; Desiante, R.; Digel, S. W.; Di Lalla, N.; Di Mauro, M.; Di Venere, L.; Domínguez, A.; Drell, P. S.; Dubois, R.; Favuzzi, C.; Ferrara, E. C.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Green, D.; Grenier, I. A.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Harding, A. K.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Jogler, T.; Jóhannesson, G.; Johnson, A. S.; Kensei, S.; Kocevski, D.; Kuss, M.; La Mura, G.; Larsson, S.; Latronico, L.; Li, J.; Li, L.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Magill, J.; Maldera, S.; Manfreda, A.; Marelli, M.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Meyer, M.; Michelson, P. F.; Mirabal, N.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Negro, M.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.; Piron, F.; Pivato, G.; Porter, T. A.; Racusin, J. L.; Rainò, S.; Rando, R.; Razzaque, S.; Reimer, A.; Reimer, O.; Salvetti, D.; Saz Parkinson, P. M.; Sgrò, C.; Simone, D.; Siskind, E. J.; Spada, F.; Spandre, G.; Spinelli, P.; Suson, D. J.; Tajima, H.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Torres, D. F.; Troja, E.; Uchiyama, Y.; Venters, T. M.; Vianello, G.; Wood, K. S.; Wood, M.; Zhu, S.; Zimmer, S.; Fermi LAT Collaboration; Brocato, E.; Cappellaro, E.; Covino, S.; Grado, A.; Nicastro, L.; Palazzi, E.; Pian, E.; Amati, L.; Antonelli, L. A.; Capaccioli, M.; D'Avanzo, P.; D'Elia, V.; Getman, F.; Giuffrida, G.; Iannicola, G.; Limatola, L.; Lisi, M.; Marinoni, S.; Marrese, P.; Melandri, A.; Piranomonte, S.; Possenti, A.; Pulone, L.; Rossi, A.; Stamerra, A.; Stella, L.; Testa, V.; Tomasella, L.; Yang, S.; GRAvitational Wave Inaf TeAm (GRAWITA); Bazzano, A.; Bozzo, E.; Brandt, S.; Courvoisier, T. J.-L.; Ferrigno, C.; Hanlon, L.; Kuulkers, E.; Laurent, P.; Mereghetti, S.; Roques, J. P.; Savchenko, V.; Ubertini, P.; INTEGRAL Collaboration; Kasliwal, M. M.; Singer, L. P.; Cao, Y.; Duggan, G.; Kulkarni, S. R.; Bhalerao, V.; Miller, A. A.; Barlow, T.; Bellm, E.; Manulis, I.; Rana, J.; Laher, R.; Masci, F.; Surace, J.; Rebbapragada, U.; Cook, D.; Van Sistine, A.; Sesar, B.; Perley, D.; Ferreti, R.; Prince, T.; Kendrick, R.; Horesh, A.; Intermediate Palomar Transient Factory (iPTF Collaboration); Hurley, K.; Golenetskii, S. V.; Aptekar, R. L.; Frederiks, D. D.; Svinkin, D. S.; Rau, A.; von Kienlin, A.; Zhang, X.; Smith, D. M.; Cline, T.; Krimm, H.; InterPlanetary Network; Abe, F.; Doi, M.; Fujisawa, K.; Kawabata, K. S.; Morokuma, T.; Motohara, K.; Tanaka, M.; Ohta, K.; Yanagisawa, K.; Yoshida, M.; J-GEM Collaboration; Baltay, C.; Rabinowitz, D.; Ellman, N.; Rostami, S.; La Silla-QUEST Survey; Bersier, D. F.; Bode, M. F.; Collins, C. A.; Copperwheat, C. M.; Darnley, M. J.; Galloway, D. K.; Gomboc, A.; Kobayashi, S.; Mazzali, P.; Mundell, C. G.; Piascik, A. S.; Pollacco, Don; Steele, I. A.; Ulaczyk, K.; Liverpool Telescope Collaboration; Broderick, J. W.; Fender, R. P.; Jonker, P. G.; Rowlinson, A.; Stappers, B. W.; Wijers, R. A. M. J.; Low Frequency Array (LOFAR Collaboration); Lipunov, V.; Gorbovskoy, E.; Tyurina, N.; Kornilov, V.; Balanutsa, P.; Kuznetsov, A.; Buckley, D.; Rebolo, R.; Serra-Ricart, M.; Israelian, G.; Budnev, N. M.; Gress, O.; Ivanov, K.; Poleshuk, V.; Tlatov, A.; Yurkov, V.; MASTER Collaboration; Kawai, N.; Serino, M.; Negoro, H.; Nakahira, S.; Mihara, T.; Tomida, H.; Ueno, S.; Tsunemi, H.; Matsuoka, M.; MAXI Collaboration; Croft, S.; Feng, L.; Franzen, T. M. O.; Gaensler, B. M.; Johnston-Hollitt, M.; Kaplan, D. L.; Morales, M. F.; Tingay, S. J.; Wayth, R. B.; Williams, A.; Murchison Wide-field Array (MWA Collaboration); Smartt, S. J.; Chambers, K. C.; Smith, K. W.; Huber, M. E.; Young, D. R.; Wright, D. E.; Schultz, A.; Denneau, L.; Flewelling, H.; Magnier, E. A.; Primak, N.; Rest, A.; Sherstyuk, A.; Stalder, B.; Stubbs, C. W.; Tonry, J.; Waters, C.; Willman, M.; Pan-STARRS Collaboration; Olivares E., F.; Campbell, H.; Kotak, R.; Sollerman, J.; Smith, M.; Dennefeld, M.; Anderson, J. P.; Botticella, M. T.; Chen, T.-W.; Della Valle, M.; Elias-Rosa, N.; Fraser, M.; Inserra, C.; Kankare, E.; Kupfer, T.; Harmanen, J.; Galbany, L.; Le Guillou, L.; Lyman, J. D.; Maguire, K.; Mitra, A.; Nicholl, M.; Razza, A.; Terreran, G.; Valenti, S.; Gal-Yam, A.; PESSTO Collaboration; Ćwiek, A.; Ćwiok, M.; Mankiewicz, L.; Opiela, R.; Zaremba, M.; Żarnecki, A. F.; Pi of Sky Collaboration; Onken, C. A.; Scalzo, R. A.; Schmidt, B. P.; Wolf, C.; Yuan, F.; SkyMapper Collaboration; Evans, P. A.; Kennea, J. A.; Burrows, D. N.; Campana, S.; Cenko, S. B.; Giommi, P.; Marshall, F. E.; Nousek, J.; O'Brien, P.; Osborne, J. P.; Palmer, D.; Perri, M.; Siegel, M.; Tagliaferri, G.; Swift Collaboration; Klotz, A.; Turpin, D.; Laugier, R.; TAROT Collaboration; Zadko Collaboration; Algerian National Observatory Collaboration; C2PU Collaboration; Beroiz, M.; Peñuela, T.; Macri, L. M.; Oelkers, R. J.; Lambas, D. G.; Vrech, R.; Cabral, J.; Colazo, C.; Dominguez, M.; Sanchez, B.; Gurovich, S.; Lares, M.; Marshall, J. L.; DePoy, D. L.; Padilla, N.; Pereyra, N. A.; Benacquista, M.; TOROS Collaboration; Tanvir, N. R.; Wiersema, K.; Levan, A. J.; Steeghs, D.; Hjorth, J.; Fynbo, J. P. U.; Malesani, D.; Milvang-Jensen, B.; Watson, D.; Irwin, M.; Fernandez, C. G.; McMahon, R. G.; Banerji, M.; Gonzalez-Solares, E.; Schulze, S.; de Ugarte Postigo, A.; Thoene, C. C.; Cano, Z.; Rosswog, S.; VISTA Collaboration

2016-07-01

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline, and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams.

High-energy Gamma-Ray Activity from V404 Cygni Detected by AGILE during the 2015 June Outburst

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

Piano, G.; Munar-Adrover, P.; Tavani, M.

The AGILE satellite detected transient high-energy γ -ray emission from the X-ray binary V404 Cygni, during the 2015 June outburst observed in radio, optical, X-ray, and soft γ -ray frequencies. The activity was observed by AGILE in the 50–400 MeV energy band, between 2015 June 24 UT 06:00:00 and 2015 June 26 UT 06:00:00 (MJD 57197.25–57199.25), with a detection significance of ∼4.3 σ . The γ -ray detection, consistent with a contemporaneous observation by Fermi -LAT, is correlated with a bright flare observed at radio and hard X-ray frequencies, and with a strong enhancement of the 511 keV line emission,more » possibly indicating plasmoid ejections in a lepton-dominated transient jet. The AGILE observations of this binary system are compatible with a microquasar scenario in which transient jets are responsible for the high-energy γ -ray emission.« less

Identification of the High-energy Gamma-Ray Source 3FGL J1544.6-1125 as a Transitional Millisecond Pulsar Binary in an Accreting State

NASA Astrophysics Data System (ADS)

Bogdanov, Slavko; Halpern, Jules P.

2015-04-01

We present X-ray, ultraviolet, and optical observations of 1RXS J154439.4-112820, the most probable counterpart of the unassociated Fermi-LAT source 3FGL J1544.6-1125. The optical data reveal rapid variability, which is a feature of accreting systems. The X-rays exhibit large-amplitude variations in the form of fast switching (within ˜10 s) between two distinct flux levels that differ by a factor of ≈10. The detailed optical and X-ray behavior is virtually identical to that seen in the accretion-disk-dominated states of the transitional millisecond pulsar (MSP) binaries PSR J1023+0038 and XSS J12270-4859, which are also associated with γ-ray sources. Based on the available observational evidence, we conclude that 1RXS J154439.4-112820 and 3FGL J1544.6-1125 are the same object, with the X-rays arising from intermittent low-luminosity accretion onto an MSP and the γ-rays originating from an accretion-driven outflow. 1RXS J154439.4-112820 is only the fourth γ-ray-emitting low-mass X-ray binary system to be identified and is likely to sporadically undergo transformations to a non-accreting rotation-powered pulsar system.

The Discovery of the Electromagnetic Counterpart of GW170817: Kilonova AT 2017gfo/DLT17ck

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

Valenti, Stefano; Yang, Sheng; Tartaglia, Leonardo

During the second observing run of the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo Interferometer, a gravitational-wave signal consistent with a binary neutron star coalescence was detected on 2017 August 17th (GW170817), quickly followed by a coincident short gamma-ray burst trigger detected by the Fermi satellite. The Distance Less Than 40 (DLT40) Mpc supernova search performed pointed follow-up observations of a sample of galaxies regularly monitored by the survey that fell within the combined LIGO+Virgo localization region and the larger Fermi gamma-ray burst error box. Here we report the discovery of a new optical transient (DLT17ck, also known as SSS17a;more » it has also been registered as AT 2017gfo) spatially and temporally coincident with GW170817. The photometric and spectroscopic evolution of DLT17ck is unique, with an absolute peak magnitude of M {sub r} = −15.8 ± 0.1 and an r -band decline rate of 1.1 mag day{sup −1}. This fast evolution is generically consistent with kilonova models, which have been predicted as the optical counterpart to binary neutron star coalescences. Analysis of archival DLT40 data does not show any sign of transient activity at the location of DLT17ck down to r ∼ 19 mag in the time period between 8 months and 21 days prior to GW170817. This discovery represents the beginning of a new era for multi-messenger astronomy, opening a new path by which to study and understand binary neutron star coalescences, short gamma-ray bursts, and their optical counterparts.« less

A population of gamma-ray emitting globular clusters seen with the Fermi Large Area Telescope

DOE PAGES

Abdo, A. A.

2010-11-24

Context. Globular clusters with their large populations of millisecond pulsars (MSPs) are believed to be potential emitters of high-energy gamma-ray emission. The observation of this emission provides a powerful tool to assess the millisecond pulsar population of a cluster, is essential for understanding the importance of binary systems for the evolution of globular clusters, and provides complementary insights into magnetospheric emission processes. Aims. Our goal is to constrain the millisecond pulsar populations in globular clusters from analysis of gamma-ray observations. Methods. We use 546 days of continuous sky-survey observations obtained with the Large Area Telescope aboard the Fermi Gamma-ray Spacemore » Telescope to study the gamma-ray emission towards 13 globular clusters. Results. Steady point-like high-energy gamma-ray emission has been significantly detected towards 8 globular clusters. Five of them (47 Tucanae, Omega Cen, NGC 6388, Terzan 5, and M 28) show hard spectral power indices (0.7 < Γ < 1.4) and clear evidence for an exponential cut-off in the range 1.0 - 2.6 GeV, which is the characteristic signature of magnetospheric emission from MSPs. Three of them (M 62, NGC 6440 and NGC 6652) also show hard spectral indices (1.0 < Γ < 1.7), however the presence of an exponential cut-off can not be unambiguously established. Three of them (Omega Cen, NGC 6388, NGC 6652) have no known radio or X-ray MSPs yet still exhibit MSP spectral properties. From the observed gamma-ray luminosities, we estimate the total number of MSPs that is expected to be present in these globular clusters. We show that our estimates of the MSP population correlate with the stellar encounter rate and we estimate 2600 - 4700 MSPs in Galactic globular clusters, commensurate with previous estimates. Conclusions. The observation of high-energy gamma-ray emission from globular clusters thus provides a reliable independent method to assess their millisecond pulsar populations.« less

Black-hole binaries as relics of gamma-ray burst/hypernova explosions

NASA Astrophysics Data System (ADS)

Moreno Mendez, Enrique

The Collapsar model, in which a fast-spinning massive star collapses into a Kerr black hole, has become the standard model to explain long-soft gamma-ray bursts and hypernova explosions (GRB/HN). However, stars massive enough (those with ZAMS mass ≳ (18--20) M⊙ ) to produce these events evolve through a path that loses too much angular momentum to produce a central engine capable of delivering the necessary energy. In this work I suggest that the soft X-ray transient sources are the remnants of GRBs/HNe. Binaries in which the massive primary star evolves a carbon-oxygen burning core, then start to transfer material to the secondary star (Case C mass transfer), causing the orbit to decay until a common-envelope phase sets in. The secondary spirals in, further narrowing the orbit of the binary and removing the hydrogen envelope of the primary star. Eventually the primary star becomes tidally locked and spins up, acquiring enough rotational energy to power up a GRB/HN explosion. The central engine producing the GRB/HN event is the Kerr black hole acting through the Blandford-Znajek mechanism. This model can explain not only the long-soft GRBs, but also the subluminous bursts (which comprise ˜ 97% of the total), the long-soft bursts and the short-hard bursts (in a neutron star, black hole merger). Because of our binary evolution through Case C mass transfer, it turns out that for the subluminous and cosmological bursts, the angular momentum O is proportional to m3/2D , where mD is the mass of the donor (secondary star). This binary evolution model has a great advantage over the Woosley Collapsar model; one can "dial" the donor mass in order to obtain whatever angular momentum is needed to drive the explosion. Population syntheses show that there are enough binaries to account for the progenitors of all known classes of GRBs.

A search for non-triggered events in the BATSE data base

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

Kommers, J. M.; Lewin, W. H. G.; Kouveliotou, C.

1998-05-16

The archival data from BATSE permit a search for transients that did not activate the onboard burst trigger. Examples of such non-triggered events include faint gamma-ray bursts (GRBs), emission from soft gamma-ray repeaters (SGRs), and bursts and flares from X-ray binaries. A GRB may fail to trigger onboard because it is too faint, because it occurs while the onboard trigger is disabled, or because it biases the onboard background estimation. We describe a search of the BATSE archival data that is sensitive to GRBs with peak fluxes fainter by a factor of {approx}2 than those detected with the onboard burstmore » trigger (on the 1.024 s time scale)« less

CdZnTe detector for hard x-ray and low energy gamma-ray focusing telescope

NASA Astrophysics Data System (ADS)

Natalucci, L.; Alvarez, J. M.; Barriere, N.; Caroli, E.; Curado da Silva, R. M.; Del Sordo, S.; Di Cosimo, S.; Frutti, M.; Hernanz, M.; Lozano, M.; Quadrini, E.; Pellegrini, G.; Stephen, J. B.; Ubertini, P.; Uslenghi, M. C.; Zoglauer, A.

2008-07-01

The science drivers for a new generation soft gamma-ray mission are naturally focused on the detailed study of the acceleration mechanisms in a variety of cosmic sources. Through the development of high energy optics in the energy energy range 0.05-1 MeV it will be possible to achieve a sensitivity about two orders of magnitude better than the currently operating gamma-ray telescopes. This will open a window for deep studies of many classes of sources: from Galactic X-ray binaries to magnetars, from supernova remnants to Galaxy clusters, from AGNs (Seyfert, blazars, QSO) to the determination of the origin of the hard X-/gamma-ray cosmic background, from the study of antimatter to that of the dark matter. In order to achieve the needed performance, a detector with mm spatial resolution and very high peak efficiency is needed. The instrumental characteristics of this device could eventually allow to detect polarization in a number of objects including pulsars, GRBs and bright AGNs. In this work we focus on the characteristics of the focal plane detector, based on CZT or CdTe semiconductor sensors arranged in multiple planes and viewed by a side detector to enhance gamma-ray absorption in the Compton regime. We report the preliminary results of an optimization study based on simulations and laboratory tests, as prosecution of the former design studies of the GRI mission which constitute the heritage of this activity.

VizieR Online Data Catalog: Short GRBs with Fermi GBM and Swift BAT (Burns+, 2016)

NASA Astrophysics Data System (ADS)

Burns, E.; Connaughton, V.; Zhang, B.-B.; Lien, A.; Briggs, M. S.; Goldstein, A.; Pelassa, V.; Troja, E.

2018-01-01

Compact binary system mergers are expected to generate gravitational radiation detectable by ground-based interferometers. A subset of these, the merger of a neutron star with another neutron star or a black hole, are also the most popular model for the production of short gamma-ray bursts (GRBs). The Swift Burst Alert Telescope (BAT) and the Fermi Gamma-ray Burst Monitor (GBM) trigger on short GRBs (SGRBs) at rates that reflect their relative sky exposures, with the BAT detecting 10 per year compared to about 45 for GBM. We examine the SGRB populations detected by Swift BAT and Fermi GBM. (4 data files).

The First Unambiguous Electromagnetic Counterpart to a Gravitational-Wave Signal: GRB 170817A and GW170817

NASA Astrophysics Data System (ADS)

Goldstein, Adam

2018-01-01

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 2 s prior to this GRB, the LIGO 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 short GRB and the joint science that results from this discovery.

Fermi GBM Observations During the Second Observing Run of LIGO/Virgo

NASA Astrophysics Data System (ADS)

Goldstein, Adam; Fermi-GBM

2018-01-01

The Fermi Gamma-ray Burst Monitor (GBM) is a prolific detector of gamma-ray bursts (GRBs) and detects more short duration GRBs than any other instrument currently in operation. Short GRBs are thought to be associated with the mergers of binary neutron star systems (or neutron star-black hole systems), and are therefore considered likely counterparts to gravitational-wave detections from LIGO/Virgo. We report on the GBM observations during the second observing run of LIGO/Virgo and detail the physical and astrophysical insights that might be gleaned from a joint detection of a short GRB and a gravitational-wave source.

Understanding the Progenitors of Short Gamma-Ray Bursts via their Host Galaxies: A Pilot Study

NASA Astrophysics Data System (ADS)

Cenko, S. Brad

2014-08-01

While massive star core-collapse is known to power long-duration gamma-ray bursts (GRBs), the origin of short GRBs remains unconfirmed. Studies of the host galaxies of short GRBs provide critical constraints on their progenitors, particularly if (as expected) short GRBs result from the neutron star mergers. Here we request deep Keck/LRIS imaging of short GRBs lacking securely identified hosts. By constraining the fraction of events that appear to have been 'kicked' out of their host galaxy in a more unbiased manner than past efforts, we aim to infer fundamental properties about the formation and evolution of binary neutron star systems.

UHE particle production in close binary systems

NASA Technical Reports Server (NTRS)

Hillas, A. M.

1985-01-01

Cygnus X-3 appears to generate so much power in the form of charged particles of up to approx 10 to the 17th power eV that the galaxy may need approx 1 such source on average to maintain its flux of ultra high energy cosmic rays. Accreting gas must supply the energy, and in a surprisingly ordered form, if it is correct to use a Vest-rand-Eichler model for radiation of gammas, modified by the introduction of an accretion wake. Certain relationships between 10 to the 12th power eV and 10 to the 15th power gamma rays are expected.

The BATSE Earth Occultation Catalog of Low Energy Gamma Ray Sources

NASA Technical Reports Server (NTRS)

Harmon, B. A.; WilsonHodge, C. A.; Fishman, G. J.; Paciesas, W.

2002-01-01

The Burst and Transient Source Experiment (BATSE), aboard the Compton Gamma Ray Observatory (CGRO), provided a record of the hard X-ray/low energy gamma ray sky between April 1991 and June 2000. During that time, a catalog of known sources was derived from existing catalogs such as HEAO A-4, as well as new transient sources discovered with BATSE and other X-ray monitors operating in the CGRO era. The Earth Occultation Technique was used to monitor a combination of these sources, mostly galactic, totaling to about 175 objects. The catalog will present the global properties of these sources and their probability of detection (> 10 mCrab, 20-100 keV) with BATSE. Systematic errors due to unknown sources or background components are included. Cursory analyses to search for new transients (35-80 mCrab in the 20-100 keV band) and super-orbital periods in known binary sources are also presented. Whole mission light curves and associated data production/analysis tools are being delivered to the HEASARC for public use.

The BATSE Earth Occultation Catalog of Low Energy Gamma-Ray Sources

NASA Technical Reports Server (NTRS)

Harmon, B. A.; Wilson-Hodge, C. A.; Fishman, G. J.; Paciesas, W. S.; Zhang, S. N.; Finger, M. H.; Connaughton, V.; Koshut, T. M.; Henze, W.; McCollough, M. L.

2004-01-01

The Burst and Transient Source Experiment (BATSE),aboard the COmptOn Gamma Ray Observatory (CGRO), provided a record of the hard X-ray/low energy gamma ray sky between April 1991 and June 2000. During that time, a catalog of known sources was derived from existing catalogs such as HEAO A-4 (Levine et al. 19841, as well as new transient sources discovered with RATSE and other X-ray monitors operating in the CGRO era. The Earth Occultation Technique (Harmon et al. 2001, astro-ph/0109069) was used to monitor a combination of these sources, mostly galactic, totaling about 175 objects. The catalog will present the global properties of these sources and their probability of detection (>lO mCrab, 20-100 keV) with BATSE. Systematic errors due to unknown sources or background components are included. Cursory analyses to search for new transients (35-80 mCrab in the 20-100 keV band) and super-orbital periods in known binary sources are also presented. Whole mission light curves and associated data production/analysis tools are being delivered to the HEASARC for public use.

Predicting supernova associated to gamma-ray burst 130427a

NASA Astrophysics Data System (ADS)

Wang, Y.; Ruffini, R.; Kovacevic, M.; Bianco, C. L.; Enderli, M.; Muccino, M.; Penacchioni, A. V.; Pisani, G. B.; Rueda, J. A.

2015-07-01

Binary systems constituted by a neutron star and a massive star are not rare in the universe. The Induced Gravitational Gamma-ray Burst (IGC) paradigm interprets Gamma-ray bursts as the outcome of a neutron star that collapses into a black hole due to the accretion of the ejecta coming from its companion massive star that underwent a supernova event. GRB 130427A is one of the most luminous GRBs ever observed, of which isotropic energy exceeds 1054 erg. And it is within one of the few GRBs obtained optical, X-ray and GeV spectra simultaneously for hundreds of seconds, which provides an unique opportunity so far to understand the multi-wavelength observation within the IGC paradigm, our data analysis found low Lorentz factor blackbody emission in the Episode 3 and its X-ray light curve overlaps typical IGC Golden Sample, which comply to the IGC mechanisms. We consider these findings as clues of GRB 130427A belonging to the IGC GRBs. We predicted on GCN the emergence of a supernova on May 2, 2013, which was later successfully detected on May 13, 2013.

7th International Fermi Symposium

NASA Astrophysics Data System (ADS)

2017-10-01

The two Fermi instruments have been surveying the high-energy sky since August 2008. The Large Area Telescope (LAT) has discovered more than three thousand gamma-ray sources and many new source classes, bringing the importance of gamma-ray astrophysics to an ever-broadening community. The LAT catalog includes supernova remnants, pulsar wind nebulae, pulsars, binary systems, novae, several classes of active galaxies, starburst galaxies, normal galaxies, and a large number of unidentified sources. Continuous monitoring of the high-energy gamma-ray sky has uncovered numerous outbursts from a wide range of transients. Fermi LAT's study of diffuse gamma-ray emission in our Galaxy revealed giant bubbles, as well as an excess of gamma-rays from the Galactic center region, both observations have become exciting puzzles for the astrophysics community. The direct measurement of a harder-than- expected cosmic-ray electron spectrum may imply the presence of nearby cosmic-ray accelerators. LAT data have provided stringent constraints on new phenomena such as supersymmetric dark-matter annihilations as well as tests of fundamental physics. The full reprocessing of the entire mission dataset with Pass 8 includes improved event reconstruction, a wider energy range, better energy measurements, and significantly increased effective area, all them boosting the discovery potential and the ability to do precision observations with LAT. The Gamma-ray Burst Monitor (GBM) continues to be a prolific detector of gamma-ray transients: magnetars, solar flares, terrestrial gamma-ray flashes and gamma-ray bursts at keV to MeV energies, complementing the higher energy LAT observations of those sources in addition to providing valuable science return in their own right. All gamma-ray data are made immediately available at the Fermi Science Support Center (http://fermi.gsfc.nasa.gov/ssc). These publicly available data and Fermi analysis tools have enabled a large number of important studies. We especially encourage guest investigators worldwide to participate in this symposium to share results and to learn about upcoming opportunities. This meeting will focus on the new scientific investigations and results enabled by Fermi, the mission and instrument characteristics, future opportunities, coordinated observations and analysis techniques. In particular, we also encourage discussion of future prospects/science with Fermi in preparation for the upcoming NASA senior review. Details on the 7th International Fermi Symposium can be found here: https://events.mpe.mpg.de/Fermi2017

Very High Energy Emission from the Binary System Cyg X-3

NASA Astrophysics Data System (ADS)

Sinitsyna, V. G.; Sinitsyna, V. Yu.

2018-03-01

Cyg X-3 is actively studied in the entire range of the electromagnetic spectrum from the radio band to ultrahigh energies. Based on the detection of ultrahigh-energy gamma-ray emission, it has been suggested that Cyg X-3 could be one of the most powerful sources of charged cosmic-ray particles in the Galaxy. We present the results of long-term observations of the Cygnus X-3 region at energies 800 GeV-100 TeV by the SHALON mirror Cherenkov telescope. In 1995 the SHALON observations revealed a new Galactic source of very high energy gamma-ray emission coincident in its coordinates with the microquasar Cyg X-3. To reliably identify the detected source with Cyg X-3, an analysis has been performed and an orbital period of 4.8 h has been found, which is a signature of Cyg X-3. A series of flares in Cyg X-3 at energies >800 GeV and their correlation with the activity in the X-ray and radio bands have been observed. The results obtained in a wide energy range for Cyg X-3, including those during the periods of relativistic jet events, are needed to find the connection and to understand the different components of an accreting binary system.

Gamma Ray Bursts and the Birth of Black Holes

NASA Technical Reports Server (NTRS)

Gehrels, Neil

2009-01-01

Black holes have been predicted since the 1940's from solutions of Einstein's general relativity field equation. There is strong evidence of their existence from astronomical observations, but their origin has remained an open question of great interest. Gamma-ray bursts may the clue. They are powerful explosions, visible to high redshift, and appear to be the birth cries of black holes. The Swift and Fermi missions are two powerful NASA observatories currently in orbit that are discovering how gamma-ray bursts work. Evidence is building that the long and short duration subcategories of GRBs have very different origins: massive star core collapse to a black hole for long bursts and binary neutron star coalescence to a black hole for short bursts. The similarity to Type II and Ia supernovae originating from young and old stellar progenitors is striking. Bursts are tremendously luminous and are providing a new tool to study the high redshift universe. One Swift burst at z=8.3 is the most distant object known in the universe. The talk will present the latest gamma-ray burst results from Swift and Fermi and will highlight what they are teaching us about black holes and jet outflows.

Observing the Non-Thermal Universe with the Highest Energy Photons

NASA Astrophysics Data System (ADS)

Dingus, Brenda L.; HAWC, VERITAS, CTA

2016-01-01

Astrophysical sources of relativistic particles radiate gamma rays to such high energies that they can be detected from the ground. The existence of high energy gamma rays implies that even higher energy particles are being accelerated placing strong constraints on these non-thermal accelerators. Within our galaxy, TeV gamma rays have been detected from supernova remnants, pulsar wind nebula, x-ray binaries and some yet to be identified sources in the Galactic plane. In addition, these gamma rays have sufficient energy to be attenuated by the interaction with infrared photons producing an electron-positron pair. Thus the spectrum of gamma rays can also constrain the infrared photon density, which for distant extragalactic sources is a direct probe of cosmology. The known extragalactic TeV sources are primarily the blazer class of active galactic nuclei. And TeV gamma rays might even be produced by annihilating dark matter.The US currently supports two ground-based gamma-ray observatories—HAWC and VERITAS—and NSF is developing a prototype for the international Cherenkov Telescope Array (CTA) observatory. The HAWC (High Altitude Water Cherenkov) observatory just began operation of the full detector in March 2015 and with its wide field of view scans ~2/3 of the sky each day for TeV sources. VERITAS (Very EneRgetic Imaging Telescope Array System) is an array of four imaging atmospheric Cherenkov telescopes that follows individual sources to produce lightcurves and spectra from 85 GeV to > 30 TeV. The combination of both a survey and pointed observatory is very complementary with a broad scientific reach that includes the study of extragalactic and Galactic objects as well as the search for astrophysical signatures of dark matter and the measurement of cosmic rays. I will present the current view of the TeV sky and the latest results from HAWC and VERITAS as well as plans for CTA.

SPECTRAL STATE EVOLUTION OF 4U 1820-30: THE STABILITY OF THE SPECTRAL INDEX OF THE COMPTONIZATION TAIL

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

Titarchuk, Lev; Frontera, Filippo; Seifina, Elena, E-mail: titarchuk@fe.infn.it, E-mail: lev@milkyway.gsfc.nasa.gov, E-mail: frontera@fe.infn.it, E-mail: seif@sai.msu.ru

We analyze the X-ray spectra and their timing properties of the compact X-ray binary 4U 1820-30. We establish spectral transitions in this source seen with BeppoSAX and the Rossi X-ray Timing Explorer (RXTE). During the RXTE observations (1996-2009), the source was in the soft state approximately {approx}75% of the time making the lower banana and upper banana transitions combined with long-term low-high state transitions. We reveal that all of the X-ray spectra of 4U 1820-30 are fit by a combination of a thermal (Blackbody) component, a Comptonization component (COMPTB), and a Gaussian-line component. Thus, using this spectral analysis, we findmore » that the photon power-law index {Gamma} of the Comptonization component is almost unchangeable ({Gamma} {approx} 2), while the electron temperature kT{sub e} changes from 2.9 to 21 keV during these spectral events. We also establish that for these spectral events the normalization of the COMPTB component (which is proportional to the mass accretion rate M-dot ) increases by a factor of eight when kT{sub e} decreases from 21 keV to 2.9 keV. Previously, this index stability effect was also found analyzing X-ray data for the Z-source GX 340+0 and for the atolls 4U 1728-34 and GX 3+1. Thus, we can suggest that this spectral stability property is a spectral signature of an accreting neutron star source. On the other hand, in a black hole binary {Gamma} monotonically increases with M-dot and ultimately its value saturates at large M-dot .« less

Early X-Ray Flares in GRBs

NASA Astrophysics Data System (ADS)

Ruffini, R.; Wang, Y.; Aimuratov, Y.; Barres de Almeida, U.; Becerra, L.; Bianco, C. L.; Chen, Y. C.; Karlica, M.; Kovacevic, M.; Li, L.; Melon Fuksman, J. D.; Moradi, R.; Muccino, M.; Penacchioni, A. V.; Pisani, G. B.; Primorac, D.; Rueda, J. A.; Shakeri, S.; Vereshchagin, G. V.; Xue, S.-S.

2018-01-01

We analyze the early X-ray flares in the GRB “flare–plateau–afterglow” (FPA) phase observed by Swift-XRT. The FPA occurs only in one of the seven GRB subclasses: the binary-driven hypernovae (BdHNe). This subclass consists of long GRBs with a carbon–oxygen core and a neutron star (NS) binary companion as progenitors. The hypercritical accretion of the supernova (SN) ejecta onto the NS can lead to the gravitational collapse of the NS into a black hole. Consequently, one can observe a GRB emission with isotropic energy {E}{iso}≳ {10}52 erg, as well as the associated GeV emission and the FPA phase. Previous work had shown that gamma-ray spikes in the prompt emission occur at ∼ {10}15{--}{10}17 cm with Lorentz Gamma factors {{Γ }}∼ {10}2{--}{10}3. Using a novel data analysis, we show that the time of occurrence, duration, luminosity, and total energy of the X-ray flares correlate with E iso. A crucial feature is the observation of thermal emission in the X-ray flares that we show occurs at radii ∼1012 cm with {{Γ }}≲ 4. These model-independent observations cannot be explained by the “fireball” model, which postulates synchrotron and inverse-Compton radiation from a single ultrarelativistic jetted emission extending from the prompt to the late afterglow and GeV emission phases. We show that in BdHNe a collision between the GRB and the SN ejecta occurs at ≃1010 cm, reaching transparency at ∼1012 cm with {{Γ }}≲ 4. The agreement between the thermal emission observations and these theoretically derived values validates our model and opens the possibility of testing each BdHN episode with the corresponding Lorentz Gamma factor.

An origin for short gamma-ray bursts unassociated with current star formation.

PubMed

Barthelmy, S D; Chincarini, G; Burrows, D N; Gehrels, N; Covino, S; Moretti, A; Romano, P; O'Brien, P T; Sarazin, C L; Kouveliotou, C; Goad, M; Vaughan, S; Tagliaferri, G; Zhang, B; Antonelli, L A; Campana, S; Cummings, J R; D'Avanzo, P; Davies, M B; Giommi, P; Grupe, D; Kaneko, Y; Kennea, J A; King, A; Kobayashi, S; Melandri, A; Meszaros, P; Nousek, J A; Patel, S; Sakamoto, T; Wijers, R A M J

2005-12-15

Two short (< 2 s) gamma-ray bursts (GRBs) have recently been localized and fading afterglow counterparts detected. The combination of these two results left unclear the nature of the host galaxies of the bursts, because one was a star-forming dwarf, while the other was probably an elliptical galaxy. Here we report the X-ray localization of a short burst (GRB 050724) with unusual gamma-ray and X-ray properties. The X-ray afterglow lies off the centre of an elliptical galaxy at a redshift of z = 0.258 (ref. 5), coincident with the position determined by ground-based optical and radio observations. The low level of star formation typical for elliptical galaxies makes it unlikely that the burst originated in a supernova explosion. A supernova origin was also ruled out for GRB 050709 (refs 3, 31), even though that burst took place in a galaxy with current star formation. The isotropic energy for the short bursts is 2-3 orders of magnitude lower than that for the long bursts. Our results therefore suggest that an alternative source of bursts--the coalescence of binary systems of neutron stars or a neutron star-black hole pair--are the progenitors of short bursts.

IDENTIFICATION OF THE HIGH-ENERGY GAMMA-RAY SOURCE 3FGL J1544.6–1125 AS A TRANSITIONAL MILLISECOND PULSAR BINARY IN AN ACCRETING STATE

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

Bogdanov, Slavko; Halpern, Jules P.

We present X-ray, ultraviolet, and optical observations of 1RXS J154439.4–112820, the most probable counterpart of the unassociated Fermi-LAT source 3FGL J1544.6–1125. The optical data reveal rapid variability, which is a feature of accreting systems. The X-rays exhibit large-amplitude variations in the form of fast switching (within ∼10 s) between two distinct flux levels that differ by a factor of ≈10. The detailed optical and X-ray behavior is virtually identical to that seen in the accretion-disk-dominated states of the transitional millisecond pulsar (MSP) binaries PSR J1023+0038 and XSS J12270–4859, which are also associated with γ-ray sources. Based on the available observationalmore » evidence, we conclude that 1RXS J154439.4–112820 and 3FGL J1544.6–1125 are the same object, with the X-rays arising from intermittent low-luminosity accretion onto an MSP and the γ-rays originating from an accretion-driven outflow. 1RXS J154439.4–112820 is only the fourth γ-ray-emitting low-mass X-ray binary system to be identified and is likely to sporadically undergo transformations to a non-accreting rotation-powered pulsar system.« less

Localization and broadband follow-up of the gravitational-wave transient GW150914

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

Abbott, B. P.

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize themore » follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Furthermore, detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams.« less

Localization and broadband follow-up of the gravitational-wave transient GW150914

DOE PAGES

Abbott, B. P.

2016-07-20

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimates of the time, significance, and sky location of the event were shared with 63 teams of observers covering radio, optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter we describe the low-latency analysis of the GW data and present the sky localization of the first observed compact binary merger. We summarize themore » follow-up observations reported by 25 teams via private Gamma-ray Coordinates Network circulars, giving an overview of the participating facilities, the GW sky localization coverage, the timeline and depth of the observations. As this event turned out to be a binary black hole merger, there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadband campaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broad capabilities of the transient astronomy community and the observing strategies that have been developed to pursue neutron star binary merger events. Furthermore, detailed investigations of the EM data and results of the EM follow-up campaign are being disseminated in papers by the individual teams.« less

Gamma-ray follow-up studies on η Carinae

DOE PAGES

Reitberger, K.; Reimer, O.; Reimer, A.; ...

2012-08-01

Observations of high-energy γ-rays recently revealed a persistent source in spatial coincidence with the binary system η Carinae. Since modulation of the observed γ-ray flux on orbital time scales has not been reported so far, an unambiguous identification was hitherto not possible. In particular, the observations made by the Fermi Large Area Telescope (LAT) posed additional questions regarding the actual emission scenario. Analyses show two energetically distinct components in the γ-ray spectrum, which are best described by an exponentially cutoff power-law function (CPL) at energies below 10 GeV and a power-law (PL) component dominant at higher energies. The increased exposuremore » in conjunction with the improved instrumental response functions of the LAT now allow us to perform a more detailed investigation of location, spectral shape, and flux time history of the observed γ-ray emission. Furthermore, we detect a weak but regular flux decrease over time. This can be understood and interpreted in a colliding-wind binary scenario for orbital modulation of the γ-ray emission. We find that the spectral shape of the γ-ray signal agrees with a single emitting particle population in combination with significant absorption by γ-γ pair production. We are able to report on the first unambiguous detection of GeV γ-ray emission from a colliding-wind massive star binary. By studying the correlation of the flux decrease with the orbital separation of the binary components allows us to predict the behaviour up to the next periastron passage in 2014.« less

Dynamical Models for High-Energy Emission from Massive Stars

NASA Astrophysics Data System (ADS)

Owocki, Stanley %FAA(University of Delaware)

Massive stars are prominent sources of X-rays and gamma-rays detected by both targeted and survey observations from orbiting telescopes like Chandra, XMM/Newton, RXTE, and Fermi. Such high-energy emissions represent key probes of the dynamics of massive-star mass loss, and their penetration through many magnitudes of visible interstellar extinction makes them effective beacons of massive stars in distant reaches of the Galaxy, and in young, active star-forming regions. The project proposed here will develop a comprehensive theoretical framework for interpreting both surveys and targeted observations of high-energy emission from massive stars. It will build on our team's extensive experience in both theoretical models and observational analyses for three key types of emission mechanisms in the stellar wind outflows of these stars, namely: 1) Embedded Wind Shocks (EWS) arising from internal instabilities in the wind driving; 2) shocks in Colliding Wind Binary (CWB) systems; and 3) High-Mass X-ray Binaries (HMXB) systems with interaction between massive-star wind with a compact companion (neutron star or black hole). Taking advantage of commonalities in the treatment of radiative driving, hydrodynamics, shock heating and cooling, and radiation transport, we will develop radiation hydrodynamical models for the key observational signatures like energy distribution, emission line spectrum, and variability, with an emphasis on how these can be used in affiliated analyses of both surveys like the recent Chandra mapping of the Carina association, and targeted observations of galactic X-ray and gamma-ray sources associated with each of the above specific model types. The promises of new clumping-insensitive diagnostics of mass loss rates, and the connection to mass transfer and binarity, all have broad relevance for understanding the origin, evolution, and fate of massive stars, in concert with elements of NASA's Strategic Subgoal 3D. Building on our team's expertise, the project emphasizes training of a new generation of students and post-doctoral researchers to model and analyze observations by current and future NASA X-ray and gamma-ray observatories.

INTEGRAL and XMM-Newton observations of the puzzling binary system LSI +61 303

NASA Astrophysics Data System (ADS)

Chernyakova, Masha; Neronov, A.; Walter, R.

LSI +61° 303 is one of the few X-ray binaries with Be star companion from which both radio and high-energy gamma-ray emission have been observed. We present XMM-Newton and INTE- GRAL observations which reveal variability of the X-ray spectral index of the system. The X-ray spectrum is hard (photon index Γ ≃ 1.5) during the orbital phases of both high and low X-ray flux. However, the spectrum softens at the moment of transition from high to low X-ray state. The spectrum of the system in the hard X-ray band does not reveal the presence of a cut-off (or, at least a spectral break) at 10-60 keV energies, expected if the compact object is an accreting neu- tron star. The observed spectrum and spectral variability can be explained if the compact object in the system is a rotation powered pulsar. In this case the recently found X-ray spectral variability of the system on the several kiloseconds time scale can be explained by the clumpy structure of the Be star disk.

Gravitational wave: gamma-ray burst connections.

PubMed

Hough, Jim

2007-05-15

After 35 years of experimental research, we are rapidly approaching the point at which gravitational waves (GWs) from astrophysical sources may be directly detected by the long-baseline detectors LIGO (USA), GEO 600 (Germany/UK), VIRGO (Italy/France) and TAMA 300 (Japan), which are now in or coming into operation.A promising source of GWs is the coalescence of compact binary systems, events which are now believed to be the origin of short gamma-ray bursts (GRBs). In this paper, a brief review of the state of the art in detector development and exploitation will be given, with particular relevance to a search for signals associated with GRBs, and plans for the future will be discussed.

Fermi LAT Detection of a GeV Gamma-Ray Flare from the Be-Pulsar Binary System PSR B1259-63 with Rapid Variability

NASA Astrophysics Data System (ADS)

Johnson, T. J.; Wood, K. S.; Ray, P. S.; Ferrara, E. C.; Kerr, M. T.; Cheung, C. C.

2017-11-01

Using data from the Large Area Telescope (LAT), one of the two instruments on board the Fermi Gamma-ray Space Telescope, we have detected a > 100 MeV flare from PSR B1259-63 over the time interval 2017-11-02 01:47:25 UTC to 2017-11-03 06:29:13 UTC with a significance of approximately 10 sigma, a preliminary photon flux (from 100 MeV to 300 GeV) of (3.1 +/- 0.4) x 10^-6 ph/cm^2/s, and a power-law photon index of 2.6 +/- 0.1, quoted uncertainties are statistical only.

Gamma-ray burst models.

PubMed

King, Andrew

2007-05-15

I consider various possibilities for making gamma-ray bursts, particularly from close binaries. In addition to the much-studied neutron star+neutron star and black hole+neutron star cases usually considered good candidates for short-duration bursts, there are also other possibilities. In particular, neutron star+massive white dwarf has several desirable features. These systems are likely to produce long-duration gamma-ray bursts (GRBs), in some cases definitely without an accompanying supernova, as observed recently. This class of burst would have a strong correlation with star formation and occur close to the host galaxy. However, rare members of the class need not be near star-forming regions and could have any type of host galaxy. Thus, a long-duration burst far from any star-forming region would also be a signature of this class. Estimates based on the existence of a known progenitor suggest that this type of GRB may be quite common, in agreement with the fact that the absence of a supernova can only be established in nearby bursts.

Introduction: recent developments in the study of gamma-ray bursts.

PubMed

Wells, Alan; Wijers, Ralph A M J; Rees, Martin J

2007-05-15

Gamma-ray bursts (GRBs) are immensely powerful explosions, originating at cosmological distances, whose outbursts persist for durations ranging from milliseconds to tens of seconds or more. In these brief moments, the explosions radiate more energy than the Sun will release in its entire 10Gyr lifetime. Current theories attribute these phenomena to the final collapse of a massive star, or the coalescence of a binary system induced by gravity wave emission. New results from Swift and related programmes offer fresh understanding of the physics of GRBs, and of the local environments and host galaxies of burst progenitors. Bursts found at very high red shifts are new tools for exploring the intergalactic medium, the first stars and the earliest stages of galaxy formation. This Royal Society Discussion Meeting has brought together leading figures in the field, together with young researchers and students, to discuss and review the latest results from NASA's Swift Gamma-ray Burst Observatory and elsewhere, and to examine their impact on current understanding of the observed phenomena.

All-Sky Monitoring of Variable Sources with Fermi GBM

NASA Technical Reports Server (NTRS)

Wilson-Hodge, Colleen A.; Finger, Mark; Camero-Arranz, Ascension; Becklen, Elif; Jenke, Peter; Cpe. K/ K/; Steele, Iain; Case, Gary; Cherry, Mike; Rodi, James;

An experimental study of energy dependence of saturation thickness of multiply scattered gamma rays in binary alloys

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

Singh, Gurvinderjit; Singh, Bhajan, E-mail: bhajan2k1@yahoo.co.in; Sandhu, B. S.

2015-08-28

The present measurements are carried out to investigate the multiple scattering of 662 keV gamma photons emerging from targets of binary alloys (brass and soldering material). The scattered photons are detected by 51 mm × 51 mm NaI(Tl) scintillation detector whose response unscrambling converting the observed pulse–height distribution to a true photon energy spectrum, is obtained with the help of 10 × 10 inverse response matrix. The numbers of multiply scattered events, having same energy as in the singly scattered distribution, first increases with target thickness and then saturate. The application of response function of scintillation detector does not result in anymore » change of measured saturation thickness. Monte Carlo calculation supports the present experimental results.« less

Superorbital Periodic Modulation in Wind-Accretion High-Mass X-Ray Binaries from Swift Burst Alert Telescope Observations

NASA Technical Reports Server (NTRS)

Corbet, Robin H. D.; Krimm, Hans A.

2013-01-01

We report the discovery using data from the Swift-Burst Alert Telescope (BAT) of superorbital modulation in the wind-accretion supergiant high-mass X-ray binaries 4U 1909+07 (= X 1908+075), IGR J16418-4532, and IGR J16479-4514. Together with already known superorbital periodicities in 2S 0114+650 and IGR J16493-4348, the systems exhibit a monotonic relationship between superorbital and orbital periods. These systems include both supergiant fast X-ray transients and classical supergiant systems, and have a range of inclination angles. This suggests an underlying physical mechanism which is connected to the orbital period. In addition to these sources with clear detections of superorbital periods, IGR J16393-4643 (= AX J16390.4-4642) is identified as a system that may have superorbital modulation due to the coincidence of low-amplitude peaks in power spectra derived from BAT, Rossi X-Ray Timing Explorer Proportional Counter Array, and International Gamma-Ray Astrophysics Laboratory light curves. 1E 1145.1-6141 may also be worthy of further attention due to the amount of low-frequency modulation of its light curve. However, we find that the presence of superorbital modulation is not a universal feature of wind-accretion supergiant X-ray binaries.

Sentinel lymph node detection in early stage cervical cancer: a prospective study comparing preoperative lymphoscintigraphy, intraoperative gamma probe, and blue dye.

PubMed

Kara, P Pelin; Ayhan, Ali; Caner, Biray; Gültekin, Murat; Ugur, Omer; Bozkurt, M Fani; Usubutun, Alp

2008-07-01

The objective of this prospective study was to determine the feasibility of sentinel lymph node (SLN) detection in patients with cervical cancer using lymphoscintigraphy (LS), gamma probe, and blue dye. A total of 32 patients with early stage cervical cancer (FIGO IA2-IIA) who were treated with total abdominal hysterectomy and bilateral pelvic and paraortic lymphadenectomy underwent SLN biopsy. LS was performed on all the patients following the injection of 74 MBq technetium-99m-nanocolloid pericervically. The first appearing persistent focal accumulation on either dynamic or static images of LS was considered to be an SLN. Blue dye was injected just prior to surgical incision in 16 patients (50%) at the same locations as the radioactive isotope injection. During the operation, blue-stained node(s) were excised as SLNs. For gamma probe, a lymph node was accepted as an SLN, if its ex vivo radioactive counts were at least 10-fold above background radioactivity. SLNs, which were negative by routine hematoxylin and eosin (H&E) examination, were histopathologically reevaluated for the presence of micrometastases by step sectioning and immunohistochemical staining with pancytokeratin. At least one SLN was identified for each patient by gamma probe. Intraoperative gamma probe was the most sensitive method with a technical success rate of SLN detection of 100% (32/32), followed by LS 87.5% (28/32) and blue dye 68.8% (11/16), respectively. The average number of SLNs per patient detected by gamma probe was 2.09 (range 1-5). The localizations of the SLNs were external iliac 47.8%, obturatory 32.8%, common iliac 9%, paraaortic 4.4%, and paracervical 6%. Micrometastases, not detected by routine H&E were found by immunohistochemistry in one patient. On the basis of the histopathological analysis, the negative predictive value for predicting metastases was 100%, and there were no false-negative results. Preoperative LS with radiocolloids, intraoperative lymphatic mapping with blue dye and gamma probe are all feasible methods comparable with each other for SLN detection in early stage cervical cancer patients, but gamma probe is the most useful method in terms of technical success.

Short gamma-ray bursts and gravitational-wave observations from eccentric compact binaries

NASA Astrophysics Data System (ADS)

Tan, Wei-Wei; Fan, Xi-Long; Wang, F. Y.

2018-03-01

Mergers of compact binaries, such as binary neutron stars (BNSs), neutron star-black hole binaries (NSBHs) and binary black holes (BBHs), are expected to be the best candidates for sources of gravitational waves (GWs) and the leading theoretical models for short gamma-ray bursts (SGRBs). Based on observations of SGRBs, we can derive the merger rates of these compact binaries and study stochastic GW backgrounds (SGWBs) or the co-detection rates of GWs associated with SGRBs (GW-SGRBs). Before that, however, the most important thing is to derive the GW spectrum from a single GW source. Usually, a GW spectrum from a circular-orbit binary is assumed. However, observations of the large spatial offsets of SGRBs from their host galaxies imply that SGRB progenitors may be formed by dynamical processes and will merge with residual eccentricities (er). The orbital eccentricity has an important effect on GW spectra and therefore on the SGWB and GW-SGRB co-detection rate. Our results show that the power spectra of SGWBs from eccentric compact binaries are greatly suppressed at low frequencies (e.g. f ≲ 1 Hz). In particular, SGWBs from binaries with high residual eccentricities (e.g. er ≳ 0.1 for BNSs) will be hard to detect (above the detection frequency of ˜ 100 Hz). Regarding the co-detection rates of GW-SGRB events, they could be ˜1.4 times higher than the circular case within some particular ranges of er (e.g. 0.01 ≲ er ≲ 0.1 for BBHs), but greatly reduced for high residual eccentricities (e.g. er > 0.1 for BNSs). In general, BBH progenitors produce 200 and 10 times higher GW-SGRB events than BNS and NSBH progenitors, respectively. Therefore, binaries with low residual eccentricities (e.g. 0.001 ≲ er ≲ 0.1) and high total masses will be easier to detect by Advanced LIGO (aLIGO). However, only a small fraction of BBHs can be SGRB progenitors (if they can produce SGRBs), because the predicted GW-SGRB event rate (60˜100 per year) is too high compared with recent observations, unless they merge with high residual eccentricities (e.g. er > 0.7).

Multi-messenger Observations of a Binary Neutron Star Merger

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

Abbott, B. P.; Abbott, R.; Abbott, T. D.

Here, on 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay ofmore » $$\\sim 1.7\\,{\\rm{s}}$$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg 2 at a luminosity distance of $${40}_{-8}^{+8}$$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $$\\,{M}_{\\odot }$$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $$\\sim 40\\,{\\rm{Mpc}}$$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position $$\\sim 9$$ and $$\\sim 16$$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.« less

Multi-messenger Observations of a Binary Neutron Star Merger

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.; 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.; 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. R.; Constancio, M., Jr.; 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.; 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.; Griswold, B.; 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.; 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.; 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.; Marsh, P.; 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, 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.; Price, L. R.; 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. 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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.; 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; Wilson-Hodge, C. A.; Bissaldi, E.; Blackburn, L.; Briggs, M. S.; Burns, E.; Cleveland, W. H.; Connaughton, V.; Gibby, M. H.; Giles, M. 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P.; OzGrav; (Deeper, DWF; Wider; program, Faster; AST3; CAASTRO Collaborations; Tanvir, N. R.; Levan, A. J.; Cano, Z.; de Ugarte-Postigo, A.; González-Fernández, C.; Greiner, J.; Hjorth, J.; Irwin, M.; Krühler, T.; Mandel, I.; Milvang-Jensen, B.; O'Brien, P.; Rol, E.; Rosetti, S.; Rosswog, S.; Rowlinson, A.; Steeghs, D. T. H.; Thöne, C. C.; Ulaczyk, K.; Watson, D.; Bruun, S. H.; Cutter, R.; Figuera Jaimes, R.; Fujii, Y. I.; Fruchter, A. S.; Gompertz, B.; Jakobsson, P.; Hodosan, G.; Jèrgensen, U. G.; Kangas, T.; Kann, D. A.; Rabus, M.; Schrøder, S. L.; Stanway, E. R.; Wijers, R. A. M. J.; The VINROUGE Collaboration; Lipunov, V. M.; Gorbovskoy, E. S.; Kornilov, V. G.; Tyurina, N. V.; Balanutsa, P. V.; Kuznetsov, A. S.; Vlasenko, D. M.; Podesta, R. C.; Lopez, C.; Podesta, F.; Levato, H. O.; Saffe, C.; Mallamaci, C. C.; Budnev, N. M.; Gress, O. A.; Kuvshinov, D. A.; Gorbunov, I. A.; Vladimirov, V. V.; Zimnukhov, D. S.; Gabovich, A. V.; Yurkov, V. V.; Sergienko, Yu. P.; Rebolo, R.; Serra-Ricart, M.; Tlatov, A. G.; Ishmuhametova, Yu. V.; MASTER Collaboration; Abe, F.; Aoki, K.; Aoki, W.; Asakura, Y.; Baar, S.; Barway, S.; Bond, I. A.; Doi, M.; Finet, F.; Fujiyoshi, T.; Furusawa, H.; Honda, S.; Itoh, R.; Kanda, N.; Kawabata, K. S.; Kawabata, M.; Kim, J. H.; Koshida, S.; Kuroda, D.; Lee, C.-H.; Liu, W.; Matsubayashi, K.; Miyazaki, S.; Morihana, K.; Morokuma, T.; Motohara, K.; Murata, K. L.; Nagai, H.; Nagashima, H.; Nagayama, T.; Nakaoka, T.; Nakata, F.; Ohsawa, R.; Ohshima, T.; Ohta, K.; Okita, H.; Saito, T.; Saito, Y.; Sako, S.; Sekiguchi, Y.; Sumi, T.; Tajitsu, A.; Takahashi, J.; Takayama, M.; Tamura, Y.; Tanaka, I.; Tanaka, M.; Terai, T.; Tominaga, N.; Tristram, P. J.; Uemura, M.; Utsumi, Y.; Yamaguchi, M. S.; Yasuda, N.; Yoshida, M.; Zenko, T.; J-GEM; Adams, S. M.; Anupama, G. C.; Bally, J.; Barway, S.; Bellm, E.; Blagorodnova, N.; Cannella, C.; Chandra, P.; Chatterjee, D.; Clarke, T. E.; Cobb, B. E.; Cook, D. O.; Copperwheat, C.; De, K.; Emery, S. W. K.; Feindt, U.; Foster, K.; Fox, O. D.; Frail, D. A.; Fremling, C.; Frohmaier, C.; Garcia, J. A.; Ghosh, S.; Giacintucci, S.; Goobar, A.; Gottlieb, O.; Grefenstette, B. W.; Hallinan, G.; Harrison, F.; Heida, M.; Helou, G.; Ho, A. Y. Q.; Horesh, A.; Hotokezaka, K.; Ip, W.-H.; Itoh, R.; Jacobs, Bob; Jencson, J. E.; Kasen, D.; Kasliwal, M. M.; Kassim, N. E.; Kim, H.; Kiran, B. S.; Kuin, N. P. M.; Kulkarni, S. R.; Kupfer, T.; Lau, R. M.; Madsen, K.; Mazzali, P. A.; Miller, A. A.; Miyasaka, H.; Mooley, K.; Myers, S. T.; Nakar, E.; Ngeow, C.-C.; Nugent, P.; Ofek, E. O.; Palliyaguru, N.; Pavana, M.; Perley, D. A.; Peters, W. M.; Pike, S.; Piran, T.; Qi, H.; Quimby, R. M.; Rana, J.; Rosswog, S.; Rusu, F.; Sadler, E. M.; Van Sistine, A.; Sollerman, J.; Xu, Y.; Yan, L.; Yatsu, Y.; Yu, P.-C.; Zhang, C.; Zhao, W.; GROWTH; JAGWAR; Caltech-NRAO; TTU-NRAO; NuSTAR Collaborations; Chambers, K. C.; Huber, M. E.; Schultz, A. S. B.; Bulger, J.; Flewelling, H.; Magnier, E. A.; Lowe, T. B.; Wainscoat, R. J.; Waters, C.; Willman, M.; Pan-STARRS; Ebisawa, K.; Hanyu, C.; Harita, S.; Hashimoto, T.; Hidaka, K.; Hori, T.; Ishikawa, M.; Isobe, N.; Iwakiri, W.; Kawai, H.; Kawai, N.; Kawamuro, T.; Kawase, T.; Kitaoka, Y.; Makishima, K.; Matsuoka, M.; Mihara, T.; Morita, T.; Morita, K.; Nakahira, S.; Nakajima, M.; Nakamura, Y.; Negoro, H.; Oda, S.; Sakamaki, A.; Sasaki, R.; Serino, M.; Shidatsu, M.; Shimomukai, R.; Sugawara, Y.; Sugita, S.; Sugizaki, M.; Tachibana, Y.; Takao, Y.; Tanimoto, A.; Tomida, H.; Tsuboi, Y.; Tsunemi, H.; Ueda, Y.; Ueno, S.; Yamada, S.; Yamaoka, K.; Yamauchi, M.; Yatabe, F.; Yoneyama, T.; Yoshii, T.; The MAXI Team; Coward, D. M.; Crisp, H.; Macpherson, D.; Andreoni, I.; Laugier, R.; Noysena, K.; Klotz, A.; Gendre, B.; Thierry, P.; Turpin, D.; Consortium, TZAC; Im, M.; Choi, C.; Kim, J.; Yoon, Y.; Lim, G.; Lee, S.-K.; Lee, C.-U.; Kim, S.-L.; Ko, S.-W.; Joe, J.; Kwon, M.-K.; Kim, P.-J.; Lim, S.-K.; Choi, J.-S.; KU Collaboration; Fynbo, J. P. U.; Malesani, D.; Xu, D.; Optical Telescope, Nordic; Smartt, S. J.; Jerkstrand, A.; Kankare, E.; Sim, S. A.; Fraser, M.; Inserra, C.; Maguire, K.; Leloudas, G.; Magee, M.; Shingles, L. J.; Smith, K. W.; Young, D. R.; Kotak, R.; Gal-Yam, A.; Lyman, J. D.; Homan, D. S.; Agliozzo, C.; Anderson, J. P.; Angus, C. R.; Ashall, C.; Barbarino, C.; Bauer, F. E.; Berton, M.; Botticella, M. T.; Bulla, M.; Cannizzaro, G.; Cartier, R.; Cikota, A.; Clark, P.; De Cia, A.; Della Valle, M.; Dennefeld, M.; Dessart, L.; Dimitriadis, G.; Elias-Rosa, N.; Firth, R. E.; Flörs, A.; Frohmaier, C.; Galbany, L.; González-Gaitán, S.; Gromadzki, M.; Gutiérrez, C. P.; Hamanowicz, A.; Harmanen, J.; Heintz, K. E.; Hernandez, M.-S.; Hodgkin, S. T.; Hook, I. M.; Izzo, L.; James, P. A.; Jonker, P. G.; Kerzendorf, W. E.; Kostrzewa-Rutkowska, Z.; Kromer, M.; Kuncarayakti, H.; Lawrence, A.; Manulis, I.; Mattila, S.; McBrien, O.; Müller, A.; Nordin, J.; O'Neill, D.; Onori, F.; Palmerio, J. T.; Pastorello, A.; Patat, F.; Pignata, G.; Podsiadlowski, P.; Razza, A.; Reynolds, T.; Roy, R.; Ruiter, A. J.; Rybicki, K. A.; Salmon, L.; Pumo, M. L.; Prentice, S. J.; Seitenzahl, I. R.; Smith, M.; Sollerman, J.; Sullivan, M.; Szegedi, H.; Taddia, F.; Taubenberger, S.; Terreran, G.; Van Soelen, B.; Vos, J.; Walton, N. A.; Wright, D. E.; Wyrzykowski, Ł.; Yaron, O.; pre="(">ePESSTO,

2017-10-01

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient's position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta. Any correspondence should be addressed to .

Multi-messenger Observations of a Binary Neutron Star Merger

DOE PAGES

Abbott, B. P.; Abbott, R.; Abbott, T. D.; ...

2017-10-16

Here, on 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay ofmore » $$\\sim 1.7\\,{\\rm{s}}$$ with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg 2 at a luminosity distance of $${40}_{-8}^{+8}$$ Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 $$\\,{M}_{\\odot }$$. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at $$\\sim 40\\,{\\rm{Mpc}}$$) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position $$\\sim 9$$ and $$\\sim 16$$ days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.« less

Adsorption of sophorolipid biosurfactants on their own and mixed with sodium dodecyl benzene sulfonate, at the air/water interface.

PubMed

Chen, Minglei; Dong, Chuchuan; Penfold, Jeff; Thomas, Robert K; Smyth, Thomas J P; Perfumo, Amedea; Marchant, Roger; Banat, Ibrahim M; Stevenson, Paul; Parry, Alyn; Tucker, Ian; Campbell, Richard A

2011-07-19

The adsorption of the lactonic (LS) and acidic (AS) forms of sophorolipid and their mixtures with the anionic surfactant sodium dodecyl benzene sulfonate (LAS) has been measured at the air/water interface by neutron reflectivity, NR. The AS and LS sophorolipids adsorb with Langmuir-like adsorption isotherms. The more hydrophobic LS is more surface active than the AS, with a lower critical micellar concentration, CMC, and stronger surface adsorption, with an area/molecule ∼70 Å(2) compared with 85 Å(2) for the AS. The acidic sophorolipid shows a maximum in its adsorption at the CMC which appears to be associated with a mixture of different isomeric forms. The binary LS/AS and LS/LAS mixtures show a strong surface partitioning in favor of the more surface active and hydrophobic LS component but are nevertheless consistent with ideal mixing at the interface. In contrast, the surface composition of the AS/LAS mixture is much closer to the solution composition, but the surface mixing is nonideal and can be accounted for by regular solution theory, RST. In the AS/LS/LAS ternary mixtures, the surface adsorption is dominated by the sophorolipid, and especially the LS component, in a way that is not consistent with the observations for the binary mixtures. The extreme partitioning in favor of the sophorolipid for the LAS/LS/AS (1:2) mixtures is attributed to a reduction in the packing constraints at the surface due to the AS component. Measurements of the surface structure reveal a compact monolayer for LS and a narrow solvent region for LS, LS/AS, and LS/LAS mixtures, consistent with the more hydrophobic nature of the LS component. The results highlight the importance of the relative packing constraints on the adsorption of multicomponent mixtures, and the impact of the lactonic form of the sophorolipid on the adsorption of the sophorolipid/LAS mixtures.

Searching for Short GRBs in Soft Gamma Rays with INTEGRAL/PICsIT

NASA Astrophysics Data System (ADS)

Rodi, James; Bazzano, Angela; Ubertini, Pietro; Natalucci, Lorenzo; Savchenko, V.; Kuulkers, E.; Ferrigno, Carlo; Bozzo, Enrico; Brandt, Soren; Chenevez, Jerome; Courvoisier, T. J.-L.; Diehl, R.; Domingo, A.; Hanlon, L.; Jourdain, E.; von Kienlin, A.; Laurent, P.; Lebrun, F.; Lutovinov, A.; Martin-Carrillo, A.; Mereghetti, S.; Roques, J.-P.; Sunyaev, R.

2018-01-01

With gravitational wave (GW) detections by the LIGO/Virgo collaboration over the past several years, there is heightened interest in gamma-ray bursts (GRBs), especially “short” GRBs (T90 <2s). The high-energy PICsIT detector (~0.2 – 10 MeV) on-board the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL) is able to observe sources out to approximately 70° off-axis, making it essentially a soft gamma-ray, all-sky monitor for impulsive events, such as SGRBs. Because SGRBs typically have hard spectra with peak energies of a few hundred keV, PICsIT with its ~ 3000 cm2 collecting area is able to provide spectral information about these sources at soft gamma-ray energies.We have begun a study of PICsIT data for faint SGRBs similar to the one associated with the binary neutron star (BNS) merger GW 170817, and also are preparing for future GW triggers by developing a real-time burst analysis for PICsIT. Searching the PICsIT data for significant excesses during ~30 min-long pointings containing times of SGRBs, we have been able to differentiate between SGRBs and spurious events. Also, this work allows us to assess what fraction of reported SGRBs have been detected by PICsIT, which can be used to provide an estimate of the number of GW BNS events seen by PICsIT during the next LIGO/Virgo observing run starting in Fall 2018.

The BATSE Earth Occultation Catalog of Low Energy Gamma Ray Sources

NASA Technical Reports Server (NTRS)

Harmon, B. A.; Wilson-Hodge, C. A.; Fishman, G. J.; Paciesas, W. S.; Zhang, S. N.; Finger, M. H.; Connaughton, V.; Koshut, T. M.; Henze, W.; McCollough, M. L.;

High-Energy Astrophysics. American and Soviet Perspectives

NASA Technical Reports Server (NTRS)

Lewin, Walter H. G. (Editor); Clark, George W. (Editor); Sunyaev, Rashid A. (Editor); Trivers, Kathleen Kearney (Editor); Abramson, David M. (Editor)

1991-01-01

The proceedings of the American-Soviet high energy astrophysics workshop, which was held at the Institute for Space Research in Moscow and the Abastumani Laboratory and Observatory in the republic of Georgia from June 18 to July 1, 1989, is presented. Topics discussed at the workshop include the inflationary universe; the large scale structure of the universe, the diffuse x-ray background; gravitational lenses, quasars, and active galactic nuclei (AGNs); infrared galaxies (results from IRAS); Supernova 1987A; millisecond radio pulsars; quasi-periodic oscillations in the x-ray flux of low mass X-ray binaries; and gamma ray bursts.

Late evolution of very low mass X-ray binaries sustained by radiation from their primaries

NASA Technical Reports Server (NTRS)

Ruderman, M.; Shaham, J.; Tavani, M.; Eichler, D.

1989-01-01

The accretion-powered radiation from the X-ray pulsar system Her X-1 (McCray et al. 1982) is studied. The changes in the soft X-ray and gamma-ray flux and in the accompanying electron-positron wind are discussed. These are believed to be associated with the inward movement of the inner edge of the accretion disk corresponding to the boundary with the neutron star's corotating magnetosphere (Alfven radius). LMXB evolution which is self-sustained by secondary winds intercepting the radiation emitted near an LMXB neutron star is investigated as well.

Prognostic indicators of poor short-term outcome of physiotherapy intervention in women with stress urinary incontinence.

PubMed

Hendriks, Erik J M; Kessels, Alfons G H; de Vet, Henrica C W; Bernards, Arnold T M; de Bie, Rob A

2010-03-01

To identify prognostic indicators independently associated with poor outcome of physiotherapy intervention in women with primary or recurrent stress urinary incontinence (stress UI). A prospective cohort study was performed in physiotherapy practices in primary care to identify prognostic indicators 12 weeks after initiation of physiotherapy intervention. Patients were referred by general practitioners or urogynecologists. Risk factors for stress UI were examined as potential prognostic indicators of poor outcome. The primary outcomes were defined as poor outcome on the binary Leakage Severity scale (LS scale) and the binary global perceived effectiveness (GPE) score. Two hundred sixty-seven women, with a mean age of 47.7 (SD = 8.3), with stress UI for at least 6 months were included. At 12 weeks, 43% and 59% of the women were considered recovered on the binary LS scale and the binary GPE score, respectively. Prognostic indicators associated with poor outcome included 11 indicators based on the binary LS scale and 8 based on the binary GPE score. The prognostic indicators shared by both models show that poor recovery was associated with women with severe stress UI, POP-Q stage > II, poor outcome of physiotherapy intervention for a previous UI episode, prolonged second stage of labor, BMI > 30, high psychological distress, and poor physical health. This study provides robust evidence of clinically meaningful prognostic indicators of poor short-term outcome. These findings need to be confirmed by replication studies. (c) 2009 Wiley-Liss, Inc.

Gamma-ray timing of redback PSR J2339-0533: Hints for gravitational quadrupole moment changes

DOE PAGES

Pletsch, Holger J.; Clark, Colin J.

2015-06-25

Here, we present the results of precision gamma-ray timing measurements of the binary millisecond pulsar PSR J2339–0533, an irradiating system of the "redback" type, using data from the Fermi Large Area Telescope. We describe an optimized analysis method to determine a long-term phase-coherent timing solution spanning more than six years, including a measured eccentricity of the binary orbit and constraints on the proper motion of the system. A major result of this timing analysis is the discovery of an extreme variation of the nominal 4.6 hr orbital periodmore » $${P}_{\\mathrm{orb}}$$ over time, showing alternating epochs of decrease and increase. We inferred a cyclic modulation of $${P}_{\\mathrm{orb}}$$ with an approximate cycle duration of 4.2 yr and a modulation amplitude of $${\\rm{\\Delta }}{P}_{\\mathrm{orb}}/{P}_{\\mathrm{orb}}=2.3\\times {10}^{-7}$$. Considering different possible physical causes, the observed orbital-period modulation most likely results from a variable gravitational quadrupole moment of the companion star due to cyclic magnetic activity in its convective zone.« less

CGRO Guest Investigator Program

NASA Technical Reports Server (NTRS)

Begelman, Mitchell C.

1997-01-01

The following are highlights from the research supported by this grant: (1) Theory of gamma-ray blazars: We studied the theory of gamma-ray blazars, being among the first investigators to propose that the GeV emission arises from Comptonization of diffuse radiation surrounding the jet, rather than from the synchrotron-self-Compton mechanism. In related work, we uncovered possible connections between the mechanisms of gamma-ray blazars and those of intraday radio variability, and have conducted a general study of the role of Compton radiation drag on the dynamics of relativistic jets. (2) A Nonlinear Monte Carlo code for gamma-ray spectrum formation: We developed, tested, and applied the first Nonlinear Monte Carlo (NLMC) code for simulating gamma-ray production and transfer under much more general (and realistic) conditions than are accessible with other techniques. The present version of the code is designed to simulate conditions thought to be present in active galactic nuclei and certain types of X-ray binaries, and includes the physics needed to model thermal and nonthermal electron-positron pair cascades. Unlike traditional Monte-Carlo techniques, our method can accurately handle highly non-linear systems in which the radiation and particle backgrounds must be determined self-consistently and in which the particle energies span many orders of magnitude. Unlike models based on kinetic equations, our code can handle arbitrary source geometries and relativistic kinematic effects In its first important application following testing, we showed that popular semi-analytic accretion disk corona models for Seyfert spectra are seriously in error, and demonstrated how the spectra can be simulated if the disk is sparsely covered by localized 'flares'.

Outflows from black hole hyperaccretion systems: short and long-short gamma-ray bursts and `quasi-supernovae'

NASA Astrophysics Data System (ADS)

Song, Cui-Ying; Liu, Tong; Li, Ang

2018-06-01

The detections of some long gamma-ray bursts (LGRBs) relevant to mergers of neutron star (NS)-NS or black hole (BH)-NS, as well as some short gamma-ray bursts (SGRBs) probably produced by collapsars, muddle the boundary of two categories of gamma-ray bursts (GRBs). In both cases, a plausible candidate of central engine is a BH surrounded by a hyperaccretion disc with strong outflows, launching relativistic jets driven by Blandford-Znajek mechanism. In the framework of compact binary mergers, we test the applicability of the BH hyperaccretion inflow-outflow model on powering observed GRBs. We find that, for a low outflow ratio, ˜ 50 per cent, post-merger hyperaccretion processes could power not only all SGRBs but also most of LGRBs. Some LGRBs might originate from merger events in the BH hyperaccretion scenario, at least on the energy requirement. Moreover, kilonovae might be produced by neutron-rich outflows, and their luminosities and time-scales significantly depend on the outflow strengths. GRBs and their associated kilonovae are competitive with each other on the disc mass and total energy budgets. The stronger the outflow, the more similar the characteristics of kilonovae to supernovae (SNe). This kind of `nova' might be called `quasi-SN'.

BurstCube: A CubeSat for Gravitational Wave Counterparts

NASA Astrophysics Data System (ADS)

Perkins, Jeremy S.; Racusin, Judith; Briggs, Michael; de Nolfo, Georgia; Caputo, Regina; Krizmanic, John; McEnery, Julie E.; Shawhan, Peter; Morris, David; Connaughton, Valerie; Kocevski, Dan; Wilson-Hodge, Colleen A.; Hui, Michelle; Mitchell, Lee; McBreen, Sheila

2018-01-01

We present BurstCube, a novel CubeSat that will detect and localize Gamma-ray Bursts (GRBs). BurstCube is a selected mission that will detect long GRBs, attributed to the collapse of massive stars, short GRBs (sGRBs), resulting from binary neutron star mergers, as well as other gamma-ray transients in the energy range 10-1000 keV. sGRBs are of particular interest because they are predicted to be the counterparts of gravitational wave (GW) sources soon to be detectable by LIGO/Virgo. BurstCube contains 4 CsI scintillators coupled with arrays of compact low-power Silicon photomultipliers (SiPMs) on a 6U Dellingr bus, a flagship modular platform that is easily modifiable for a variety of 6U CubeSat architectures. BurstCube will complement existing facilities such as Swift and Fermi in the short term, and provide a means for GRB detection, localization, and characterization in the interim time before the next generation future gamma-ray mission flies, as well as space-qualify SiPMs and test technologies for future use on larger gamma-ray missions. The ultimate configuration of BurstCube is to have a set of ~10 BurstCubes to provide all-sky coverage to GRBs for substantially lower cost than a full-scale mission.

GX 3+1: The Stability of Spectral Index as a Function of Mass Accretion Rate

NASA Technical Reports Server (NTRS)

Seifana, Elena; Titarchuk, Lev

2012-01-01

We present an analysis of the spectral and timing properties observed in X-rays from neutron star (NS) binary GX 3+1 (4U 1744-26) during long-term transitions between the faint and bright phases superimposed on short-term transitions between lower banana (LB) and upper banana (UB) branches in terms of its color-color diagram, We analyze all observations of this source obtained with the Rossi X-ray Timing Explorer and BeppoSAX satellites, We find that the X-ray broadband energy spectra during these spectral transitions can be adequately reproduced by a composition of a low-temperature blackbody component, a Comptonized component (COMPTB), and Gaussian component We argue that the electron temperature kTe of the Compton cloud monotonically increases from 2.3 keY to 4.5 keY, when GX 3+1 makes a transition from UB to LB. We also detect an evolution of noise components (a very low frequency noise and a high-frequency noise) during these LB-UB transitions. Using a disk seed photon normalization of COMPTB, which is proportional to the mass accretion rate, we find that the photon power-law index Gamma is almost constant (Gamma = 2.00 +/- 0.02) when mass accretion rate changes by factor four. In addition, we find that the emergent spectrum is dominated by the strong Comptonized component We interpret this quasi-stability of the index Gamma and a particular form of the spectrum in the framework of a model in which the energy release in the transition layer located between the accretion disk and NS surface dominates that in the disk. Moreover, this index stability effect now established for GX 3+ I was previously found in the atoll source 4U 1728-34 and suggested for a number of other low-mass X-ray NS binaries. This intrinsic behavior of NSs, in particular for atoll sources, is fundamentally different from that seen in black hole binary sources where the index monotonically increases during spectral transition from the low state to the high state and then finally saturates at high values of mass accretion rate.

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.

X-ray observations of AM Herculis from OSO 8

NASA Technical Reports Server (NTRS)

Coe, M. J.; Dennis, B. R.; Dolan, J. F.; Crannell, C. J.; Frost, K. J.; Orwig, I. E.

1979-01-01

X-ray observations of the white dwarf binary system AM Herculis in the range 2 to 250 keV, taken by OSO 8, are presented and compared with balloon and Ariel 5 measurements. The composite spectrum of the 2 to 40 and 20 to 250 keV fluxes determined by the proportional counter and the high energy scintillation spectrometer, respectively, on board the satellite is shown averaged over the entire binary cycle. Variations in spectral shape and intensity between the OSO 8 results and balloon measurements taken 10 to 20 days apart are observed. Results indicate the presence of a spectral break at about 15 keV on some occasions, similar to that seen in Her X-1, however presumably caused by a different mechanism than in the neutron star. It is also considered unlikely that the gamma-ray tail observed by Ariel 5 existed during OSO 8 observations.

Design and Tests of the Hard X-Ray Polarimeter X-Calibur

NASA Technical Reports Server (NTRS)

Beilicke, M.; Binns, W. R.; Buckley, J.; Cowsik, R.; Dowkontt, P.; Garson, A.; Guo, Q.; Israel, M. H.; Lee, K.; Krawczynski, H.;

Design and Tests of the Hard X-Ray Polarimeter X-Calibur

NASA Technical Reports Server (NTRS)

Beilicke, M.; Baring, M. G.; Barthelmy, S.; Binns, W. R.; Buckley, J.; Cowsik, R.; Dowkontt, P.; Garson, A.; Guo, Q.; Haba, Y.;

Observations of accreting pulsars

NASA Technical Reports Server (NTRS)

Prince, Thomas A.; Bildsten, Lars; Chakrabarty, Deepto; Wilson, Robert B.; Finger, Mark H.

1994-01-01

We discuss recent observations of accreting binary pulsars with the all-sky BATSE instrument on the Compton Gamma Ray Observatory. BATSE has detected and studied nearly half of the known accreting pulsar systems. Continuous timing studies over a two-year period have yielded accurate orbital parameters for 9 of these systems, as well as new insights into long-term accretion torque histories.

GRB/GW Association: Long-Short GRB Candidates, Time Lag, Measuring Gravitational Wave Velocity, and Testing Einstein’s Equivalence Principle

NASA Astrophysics Data System (ADS)

Li, Xiang; Hu, Yi-Ming; Fan, Yi-Zhong; Wei, Da-Ming

2016-08-01

Short-duration gamma-ray bursts (SGRBs) are widely believed to be powered by the mergers of compact binaries, such as binary neutron stars or possibly neutron star-black hole binaries. Though the prospect of detecting SGRBs with gravitational wave (GW) signals by the advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)/VIRGO network is promising, no known SGRB has been found within the expected advanced LIGO/VIRGO sensitivity range for binary neutron star systems. We find, however, that the two long-short GRBs (GRB 060505 and GRB 060614) may be within the horizon of advanced GW detectors. In the upcoming era of GW astronomy, the merger origin of some long-short GRBs, as favored by the macronova signature displayed in GRB 060614, can be unambiguously tested. The model-dependent time lags between the merger and the onset of the prompt emission of the GRB are estimated. The comparison of such time lags between model predictions and the real data expected in the era of the GW astronomy would be helpful in revealing the physical processes taking place at the central engine (including the launch of the relativistic outflow, the emergence of the outflow from the dense material ejected during the merger, and the radiation of gamma rays). We also show that the speed of GWs, with or without a simultaneous test of Einstein’s equivalence principle, can be directly measured to an accuracy of ˜ 3× {10}-8 {cm} {{{s}}}-1 or even better in the advanced LIGO/VIRGO era.

LONG-TERM OPTICAL STUDIES OF THE BE/X-RAY BINARY RX J0440.9+4431/LS V+44 17

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

Yan, Jingzhi; Zhang, Peng; Liu, Wei

2016-04-15

We present the spectroscopic and photometric observations on the Be/X-ray binary RX J0440.9+4431 from 2001 to 2014. The short-term and long-term variability of the Hα line profile indicates that one-armed global oscillations existed in the circumstellar disk. Several positive and negative correlations between the V-band brightness and the Hα intensity were found from the long-term photometric and spectroscopic observations. We suggest that the monotonic increase of the V-band brightness and the Hα brightness between our 2005 and 2007 observations might be the result of a continuous mass ejection from the central Be star, while the negative correlation in 2007–2010 should bemore » caused by the cessation of mass loss from the Be star just before the decline in V-band brightness began (around our 2007 observations). With the extension of the ejection material, the largest circumstellar disk during the last two decades has been observed in our 2010 observations with an equivalent width of approximately −12.88 Å, which corresponds to a circumstellar disk with a size of 12.9 times the radius of the central Be star. Three consecutive X-ray outbursts peaking around MJD 55293, 55444, and 55591 might be connected with the largest circumstellar disk around the Be star. We also use the orbital motion of the neutron star as a probe to constrain the structure of the circumstellar disk and estimate the eccentricity of the binary system to be ≥0.4. After three years of the Hα intensity decline after the X-ray outbursts, a new circumstellar disk was being formed around the Be star after our 2013 observations.« less

The Advanced Gamma-ray Imaging System (AGIS): Next-generation Cherenkov telescopes array.

NASA Astrophysics Data System (ADS)

Vassiliev, Vladimir; AGIS Collaboration

2010-03-01

AGIS is a concept for a next-generation ground-based gamma-ray observatory in the energy range from 50 GeV to 200 TeV. AGIS is being designed to have significantly improved sensitivity, angular resolution, and reliability of operation relative to the present generation instruments such as VERITAS and H.E.S.S. The novel technologies of AGIS are expected to enable great advances in the understanding of the populations and physics of sources of high-energy gamma rays in the Milky Way (e.g. SNR, X-ray binaries, dense molecular clouds) and outside the Galaxy (e.g. AGN, GRBs, galaxy clusters, and star-forming galaxies). AGIS will complement and extend the results now being obtained in the GeV range with the Fermi mission providing wide energy coverage, superior angular resolution, and sensitivity to variability on short time scales. AGIS will be a key instrument for identifying and characterizing Fermi LAT sources. In this submission we outline the status of the development of AGIS project, design concept, and principal technologies. As illustrations of the scientific capabilities of AGIS, we review its potential to indirectly search for dark matter and measure cosmological magnetic fields.

Fermi-LAT upper limits on gamma-ray emission from colliding wind binaries

DOE PAGES

Werner, Michael; Reimer, O.; Reimer, A.; ...

2013-07-09

Here, colliding wind binaries (CWBs) are thought to give rise to a plethora of physical processes including acceleration and interaction of relativistic particles. Observation of synchrotron radiation in the radio band confirms there is a relativistic electron population in CWBs. Accordingly, CWBs have been suspected sources of high-energy γ-ray emission since the COS-B era. Theoretical models exist that characterize the underlying physical processes leading to particle acceleration and quantitatively predict the non-thermal energy emission observable at Earth. Furthermore, we strive to find evidence of γ-ray emission from a sample of seven CWB systems: WR 11, WR 70, WR 125, WRmore » 137, WR 140, WR 146, and WR 147. Theoretical modelling identified these systems as the most favourable candidates for emitting γ-rays. We make a comparison with existing γ-ray flux predictions and investigate possible constraints. We used 24 months of data from the Large Area Telescope (LAT) on-board the Fermi Gamma Ray Space Telescope to perform a dedicated likelihood analysis of CWBs in the LAT energy range. As a result, we find no evidence of γ-ray emission from any of the studied CWB systems and determine corresponding flux upper limits. For some CWBs the interplay of orbital and stellar parameters renders the Fermi-LAT data not sensitive enough to constrain the parameter space of the emission models. In the cases of WR140 and WR147, the Fermi -LAT upper limits appear to rule out some model predictions entirely and constrain theoretical models over a significant parameter space. A comparison of our findings to the CWB η Car is made.« less

GRB 060313: A New Paradigm for Short-Hard Bursts?

NASA Astrophysics Data System (ADS)

Roming, Peter W. A.; Vanden Berk, Daniel; Pal'shin, Valentin; Pagani, Claudio; Norris, Jay; Kumar, Pawan; Krimm, Hans; Holland, Stephen T.; Gronwall, Caryl; Blustin, Alex J.; Zhang, Bing; Schady, Patricia; Sakamoto, Takanori; Osborne, Julian P.; Nousek, John A.; Marshall, Frank E.; Mészáros, Peter; Golenetskii, Sergey V.; Gehrels, Neil; Frederiks, Dmitry D.; Campana, Sergio; Burrows, David N.; Boyd, Patricia T.; Barthelmy, Scott; Aptekar, R. L.

2006-11-01

We report the simultaneous observations of the prompt emission in the gamma-ray and hard X-ray bands by the Swift BAT and the Konus-Wind instruments of the short-hard burst, GRB 060313. The observations reveal multiple peaks in both the gamma-ray and hard X-ray bands suggesting a highly variable outflow from the central explosion. We also describe the early-time observations of the X-ray and UV/optical afterglows by the Swift XRT and UVOT instruments. The combination of the X-ray and UV/optical observations provides the most comprehensive light curves to date of a short-hard burst at such an early epoch. The afterglows exhibit complex structure with different decay indices and flaring. This behavior can be explained by the combination of a structured jet, radiative loss of energy, and decreasing microphysics parameters occurring in a circumburst medium with densities varying by a factor of approximately two on a length scale of 1017 cm. These density variations are normally associated with the environment of a massive star and inhomogeneities in its windy medium. However, the mean density of the observed medium (n~10-4 cm3) is much less than that expected for a massive star. Although the collapse of a massive star as the origin of GRB 060313 is unlikely, the merger of a compact binary also poses problems for explaining the behavior of this burst. Two possible suggestions for explaining this scenario are that some short bursts may arise from a mechanism that does not invoke the conventional compact binary model, or that soft late-time central engine activity is producing UV/optical but no X-ray flaring.

The Burst and Transient Source Experiment (BATSE) Earth Occultation Catalog of Low-Energy Gamma-Ray Sources

NASA Technical Reports Server (NTRS)

Harmon, B. A.; Wilson, C. A.; Fishman, G. J.; Connaughton, V.; Henze, W.; Paciesas, W. S.; Finger, M. H.; McCollough, M. L.; Sahi, M.; Peterson, B.

2004-01-01

The Burst and Transient Source Experiment (BATSE), aboard the Compton Gamma Ray Observatory (CGRO), provided a record of the low-energy gamma-ray sky (approx. 20-1000 keV) between 1991 April and 2000 May (9.1 yr). BATSE monitored the high-energy sky using the Earth occultation technique (EOT) for point sources whose emission extended for times on the order of the CGRO orbital period (approx. 92 min) or greater. Using the EOT to extract flux information, a catalog of sources using data from the BATSE Large Area Detectors has been prepared. The first part of the catalog consists of results from the all-sky monitoring of 58 sources, mostly Galactic, with intrinsic variability on timescales of hours to years. For these sources, we have included tables of flux and spectral data, and outburst times for transients. Light curves (or flux histories) have been placed on the World Wide Web. We then performed a deep sampling of these 58 objects, plus a selection of 121 more objects, combining data from the entire 9.1 yr BATSE data set. Source types considered were primarily accreting binaries, but a small number of representative active galaxies, X-ray-emitting stars, and supernova remnants were also included. The sample represents a compilation of sources monitored and/or discovered with BATSE and other high-energy instruments between 1991 and 2000, known sources taken from the HEAO 1 A-4 and Macomb & Gehrels catalogs. The deep sample results include definite detections of 83 objects and possible detections of 36 additional objects. The definite detections spanned three classes of sources: accreting black hole and neutron star binaries, active galaxies, and Supernova remnants. The average fluxes measured for the fourth class, the X-ray emitting stars, were below the confidence limit for definite detection.

INTEGRAL Observations of the Enigmatic Be Stars (gamma) Cassiopeiae and HD 110432

NASA Technical Reports Server (NTRS)

Sturner, S. J.; Shrader, C. R.

2007-01-01

We present the results of a hard X-ray study of the Be stars gamma Cassiopeiae and HD 110432 based on observations made with the INTEGRAL observatory. These stars are known to be moderately strong, X-ray sources (L(sub x) approx. equal to = 10(sup 32)-10(sup 33) erg per second). These values are at the extreme high end of the known luminosity distribution for active coronal systems, but several orders of magnitude below typical X-ray binaries. The hard X-ray spectra for these systems are quite similar. They can be well fitted by either optically thin thermal plasma models with kT = 12.5 - 14 keV or a cutoff powerlaw + gaussian line model with photon indices in the 1.3 - 1.5 range and a line energy of 6.7 keV. The 20-50 keV light curves show no evidence for flaring and no significant evidence for periodic variability. It has been proposed that the X-ray emission is due to either accretion onto a white dwarf companion or magnetic activity near the surface of the Be star. We discuss in detail the pros and cons of each scenario towards explaining our spectral and temporal results. Given that both thermal and nonthermal models fit the data equally well, we cannot use the spectra to delineate between these two scenarios. Recent observations indicate that gamma Cas has a approx. 1 solar mass companion in a 203.59 day orbit. This is consistent with the white dwarf - Be star binary model but the lack of periodic modulation of the flux on this timescale calls this conclusion into question. On the other hand the lack of flaring activity may rule against the magnetic activity model. We discuss advances in observations and theory that need to be made to resolve the origin of these systems.

Evolution of an electron-positron plasma produced by induced gravitational collapse in binary-driven hypernovae

NASA Astrophysics Data System (ADS)

Melon Fuksman, J. D.; Becerra, L.; Bianco, C. L.; Karlica, M.; Kovacevic, M.; Moradi, R.; Muccino, M.; Pisani, G. B.; Primorac, D.; Rueda, J. A.; Ruffini, R.; Vereshchagin, G. V.; Wang, Y.

2018-01-01

The binary-driven hypernova (BdHN) model has been introduced in the past years, to explain a subfamily of gamma-ray bursts (GRBs) with energies Eiso ≥ 1052 erg associated with type Ic supernovae. Such BdHNe have as progenitor a tight binary system composed of a carbon-oxigen (CO) core and a neutron star undergoing an induced gravitational collapse to a black hole, triggered by the CO core explosion as a supernova (SN). This collapse produces an optically-thick e+e- plasma, which expands and impacts onto the SN ejecta. This process is here considered as a candidate for the production of X-ray flares, which are frequently observed following the prompt emission of GRBs. In this work we follow the evolution of the e+e- plasma as it interacts with the SN ejecta, by solving the equations of relativistic hydrodynamics numerically. Our results are compatible with the Lorentz factors estimated for the sources that produce the flares, of typically Γ ≲ 4.

Interferon-gamma inducible protein-10 as a potential biomarker in localized scleroderma.

PubMed

Magee, Kelsey E; Kelsey, Christina E; Kurzinski, Katherine L; Ho, Jonhan; Mlakar, Logan R; Feghali-Bostwick, Carol A; Torok, Kathryn S

2013-01-01

The purpose of this study was to evaluate the presence and levels of interferon-gamma inducible protein-10 (IP-10) in the plasma and skin of pediatric localized scleroderma (LS) patients compared to those of healthy pediatric controls and to determine if IP-10 levels correlate to clinical disease activity measures. The presence of IP-10 in the plasma was analyzed using a Luminex panel in 69 pediatric patients with LS and compared to 71 healthy pediatric controls. Of these patients, five had available skin biopsy specimens with concurrent clinical and serological data during the active disease phase, which were used to analyze the presence and location of IP-10 in the skin by immunohistochemistry (IHC). IP-10 levels were significantly elevated in the plasma of LS patients compared to that of healthy controls and correlated to clinical disease activity measures in LS. Immunohistochemistry staining of IP-10 was present in the dermal infiltrate of LS patients and was similar to that found in psoriasis skin specimens, the positive disease control. Elevation of IP-10 levels in the plasma compared to those of healthy controls and the presence of IP-10 staining in the affected skin of LS patients indicates that IP-10 is a potential biomarker in LS. Furthermore, significant elevation of IP-10 in LS patients with active versus inactive disease and correlations between IP-10 levels and standardized disease outcome measures of activity in LS strongly suggest that IP-10 may be a biomarker for disease activity in LS.

Interferon-gamma inducible protein-10 as a potential biomarker in localized scleroderma

PubMed Central

2013-01-01

Introduction The purpose of this study was to evaluate the presence and levels of interferon-gamma inducible protein-10 (IP-10) in the plasma and skin of pediatric localized scleroderma (LS) patients compared to those of healthy pediatric controls and to determine if IP-10 levels correlate to clinical disease activity measures. Methods The presence of IP-10 in the plasma was analyzed using a Luminex panel in 69 pediatric patients with LS and compared to 71 healthy pediatric controls. Of these patients, five had available skin biopsy specimens with concurrent clinical and serological data during the active disease phase, which were used to analyze the presence and location of IP-10 in the skin by immunohistochemistry (IHC). Results IP-10 levels were significantly elevated in the plasma of LS patients compared to that of healthy controls and correlated to clinical disease activity measures in LS. Immunohistochemistry staining of IP-10 was present in the dermal infiltrate of LS patients and was similar to that found in psoriasis skin specimens, the positive disease control. Conclusions Elevation of IP-10 levels in the plasma compared to those of healthy controls and the presence of IP-10 staining in the affected skin of LS patients indicates that IP-10 is a potential biomarker in LS. Furthermore, significant elevation of IP-10 in LS patients with active versus inactive disease and correlations between IP-10 levels and standardized disease outcome measures of activity in LS strongly suggest that IP-10 may be a biomarker for disease activity in LS. PMID:24499523

Discovery of the short gamma-ray burst GRB 050709.

PubMed

Villasenor, J S; Lamb, D Q; Ricker, G R; Atteia, J-L; Kawai, N; Butler, N; Nakagawa, Y; Jernigan, J G; Boer, M; Crew, G B; Donaghy, T Q; Doty, J; Fenimore, E E; Galassi, M; Graziani, C; Hurley, K; Levine, A; Martel, F; Matsuoka, M; Olive, J-F; Prigozhin, G; Sakamoto, T; Shirasaki, Y; Suzuki, M; Tamagawa, T; Vanderspek, R; Woosley, S E; Yoshida, A; Braga, J; Manchanda, R; Pizzichini, G; Takagishi, K; Yamauchi, M

2005-10-06

Gamma-ray bursts (GRBs) fall into two classes: short-hard and long-soft bursts. The latter are now known to have X-ray and optical afterglows, to occur at cosmological distances in star-forming galaxies, and to be associated with the explosion of massive stars. In contrast, the distance scale, the energy scale and the progenitors of the short bursts have remained a mystery. Here we report the discovery of a short-hard burst whose accurate localization has led to follow-up observations that have identified the X-ray afterglow and (for the first time) the optical afterglow of a short-hard burst; this in turn led to the identification of the host galaxy of the burst as a late-type galaxy at z = 0.16 (ref. 10). These results show that at least some short-hard bursts occur at cosmological distances in the outskirts of galaxies, and are likely to be caused by the merging of compact binaries.

Poynting-Flux-Driven Bubbles and Shocks Around Merging Neutron Star Binaries

NASA Astrophysics Data System (ADS)

Medvedev, M. V.; Loeb, A.

2013-04-01

Merging binaries of compact relativistic objects are thought to be progenitors of short gamma-ray bursts. Because of the strong magnetic field of one or both binary members and high orbital frequencies, these binaries are strong sources of energy in the form of Poynting flux. The steady injection of energy by the binary forms a bubble filled with matter with the relativistic equation of state, which pushes on the surrounding plasma and can drive a shock wave in it. Unlike the Sedov-von Neumann-Taylor blast wave solution for a point-like explosion, the shock wave here is continuously driven by the ever-increasing pressure inside the bubble. We calculate from the first principles the dynamics and evolution of the bubble and the shock surrounding it, demonstrate that it exhibits finite time singularity and find the corresponding analytical solution. We predict that such binaries can be observed as radio sources a few hours before and after the merger.

Swope Supernova Survey 2017a (SSS17a), the optical counterpart to a gravitational wave source.

PubMed

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

2017-12-22

On 17 August 2017, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo interferometer detected gravitational waves (GWs) emanating from a binary neutron star merger, GW170817. Nearly simultaneously, the Fermi and INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory) telescopes detected a gamma-ray transient, GRB 170817A. At 10.9 hours after the GW trigger, we discovered a transient and fading optical source, Swope Supernova Survey 2017a (SSS17a), coincident with GW170817. SSS17a is located in NGC 4993, an S0 galaxy at a distance of 40 megaparsecs. The precise location of GW170817 provides an opportunity to probe the nature of these cataclysmic events by combining electromagnetic and GW observations. Copyright © 2017, American Association for the Advancement of Science.

Topological and morphological analysis of gamma rays irradiated chitosan-poly (vinyl alcohol) blends using atomic force microscopy

NASA Astrophysics Data System (ADS)

Bhatt, Rinkesh; Bisen, D. S.; Bajpai, R.; Bajpai, A. K.

2017-04-01

In the present communication, binary blends of poly (vinyl alcohol) (PVA) and chitosan (CS) were prepared by solution cast method and the roughness parameters of PVA, native CS and CS-PVA blend films were determined using atomic force microscopy (AFM). Moreover, the changes in the morphology of the samples were also investigated after irradiation of gamma rays at absorbed dose of 1 Mrad and 10 Mrad for the scanning areas of 5×5 μm2, 10×10 μm2 and 20×20 μm2. Amplitude, statistical and spatial parameters, including line, 3D and 2D image profiles of the experimental surfaces were examined and compared to un-irradiated samples. For gamma irradiated CS-PVA blends the larger waviness over the surface was found as compared to un-irradiated CS-PVA blends but the values of average roughness for both the films were found almost same. The coefficient of skewness was positive for gamma irradiated CS-PVA blends which revealed the presence of more peaks than valleys on the blend surfaces.

The afterglow and elliptical host galaxy of the short gamma-ray burst GRB 050724.

PubMed

Berger, E; Price, P A; Cenko, S B; Gal-Yam, A; Soderberg, A M; Kasliwal, M; Leonard, D C; Cameron, P B; Frail, D A; Kulkarni, S R; Murphy, D C; Krzeminski, W; Piran, T; Lee, B L; Roth, K C; Moon, D-S; Fox, D B; Harrison, F A; Persson, S E; Schmidt, B P; Penprase, B E; Rich, J; Peterson, B A; Cowie, L L

2005-12-15

Despite a rich phenomenology, gamma-ray bursts (GRBs) are divided into two classes based on their duration and spectral hardness--the long-soft and the short-hard bursts. The discovery of afterglow emission from long GRBs was a watershed event, pinpointing their origin to star-forming galaxies, and hence the death of massive stars, and indicating an energy release of about 10(51) erg. While theoretical arguments suggest that short GRBs are produced in the coalescence of binary compact objects (neutron stars or black holes), the progenitors, energetics and environments of these events remain elusive despite recent localizations. Here we report the discovery of the first radio afterglow from the short burst GRB 050724, which unambiguously associates it with an elliptical galaxy at a redshift z = 0.257. We show that the burst is powered by the same relativistic fireball mechanism as long GRBs, with the ejecta possibly collimated in jets, but that the total energy release is 10-1,000 times smaller. More importantly, the nature of the host galaxy demonstrates that short GRBs arise from an old (> 1 Gyr) stellar population, strengthening earlier suggestions and providing support for coalescing compact object binaries as the progenitors.

Giant Rapid X-ray Flares in Extragalactic Globular Clusters

NASA Astrophysics Data System (ADS)

Irwin, Jimmy

2018-01-01

There is only one known class of non-destructive, highly energetic astrophysical object in the Universe whose energy emission varies by more than a factor of 100 on time scales of less than a minute -- soft gamma repeaters/anomalous X-ray pulsars, whose flares are believed to be caused by the energy release from the cracking of a neutron star's surface by very strong magnetic fields. All other known violent, rapid explosions, including gamma-ray bursts and supernovae, are believed to destroy the object in the process. Here, we report the discovery of a second class of non-destructive, highly energetic rapidly flaring X-ray object located within two nearby galaxies with fundamentally different properties than soft gamma repeaters/anomalous X-ray pulsars. One source is located within a suspected globular cluster of the host galaxy and flared one time, while the other source is located in either a globular cluster of the host galaxy or the core of a stripped dwarf companion galaxy that flared on six occasions over a seven year time span. When not flaring, the sources appear as normal accreting neutron star or black hole X-ray binaries, indicating that the flare event does not significantly disrupt the host system. While the nature of these sources is still unclear, the discovery of these sources in decade-old archival Chandra X-ray Observatory data illustrates the under-utilization of X-ray timing as a means to discover new classes of explosive events in the Universe.

Discovery of the VHE gamma-ray source HESS J1832-093 in the vicinity of SNR G22.7-0.2

NASA Astrophysics Data System (ADS)

HESS Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Ait Benkhali, F.; Akhperjanian, A. G.; Angüner, E.; Anton, G.; Balenderan, S.; Balzer, A.; Barnacka, A.; Becherini, Y.; Becker Tjus, J.; Bernlöhr, K.; Birsin, E.; Bissaldi, E.; Biteau, J.; Böttcher, M.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Chalme-Calvet, R.; Chaves, R. C. G.; Cheesebrough, A.; Chrétien, M.; Clapson, A.-C.; Colafrancesco, S.; Cologna, G.; Conrad, J.; Couturier, C.; Cui, Y.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; deWilt, P.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Edwards, T.; Egberts, K.; Eger, P.; Espigat, P.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fernandez, D.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gajdus, M.; Gallant, Y. A.; Garrigoux, T.; Giavitto, G.; Giebels, B.; Glicenstein, J. F.; Grondin, M.-H.; Grudzińska, M.; Häffner, S.; Hahn, J.; Harris, J.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hervet, O.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; Jahn, C.; Jamrozy, M.; Janiak, M.; Jankowsky, F.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Khélifi, B.; Kieffer, M.; Klepser, S.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Kolitzus, D.; Komin, Nu.; Kosack, K.; Krakau, S.; Krayzel, F.; Krüger, P. P.; Laffon, H.; Lamanna, G.; Lefaucheur, J.; Lemière, A.; Lemoine-Goumard, M.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Marx, R.; Maurin, G.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Méhault, J.; Meintjes, P. J.; Menzler, U.; Meyer, M.; Moderski, R.; Mohamed, M.; Moulin, E.; Murach, T.; Naumann, C. L.; de Naurois, M.; Niemiec, J.; Nolan, S. J.; Oakes, L.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Parsons, R. D.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Perez, J.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Poon, H.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raab, S.; Raue, M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Rob, L.; Romoli, C.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schüssler, F.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sol, H.; Spengler, G.; Spies, F.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Tavernier, T.; Taylor, A. M.; Terrier, R.; Tluczykont, M.; Trichard, C.; Valerius, K.; van Eldik, C.; van Soelen, B.; Vasileiadis, G.; Venter, C.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorster, M.; Vuillaume, T.; Wagner, S. J.; Wagner, P.; Ward, M.; Weidinger, M.; Weitzel, Q.; White, R.; Wierzcholska, A.; Willmann, P.; Wörnlein, A.; Wouters, D.; Zabalza, V.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.

2015-01-01

The region around the supernova remnant (SNR) W41 contains several TeV sources and has prompted the HESS Collaboration to perform deep observations of this field of view. This resulted in the discovery of the new very high energy (VHE) source HESS J1832-093, at the position {RA=18^h 32^m 50^s ± 3^s_{stat} ± 2^s_{syst}}, {Dec=-9*deg;22'36" ± 32"}_{stat} ± 20^' '}_{syst} (J2000)}, spatially coincident with a part of the radio shell of the neighbouring remnant G22.7-0.2. The photon spectrum is well described by a power law of index Γ = 2.6 ± 0.3stat ± 0.1syst and a normalization at 1 TeV of Φ _0=(4.8 ± 0.8_stat± 1.0_syst) × 10^{-13} cm ^{-2} s^{-1} TeV^{-1}. The location of the gamma-ray emission on the edge of the SNR rim first suggested a signature of escaping cosmic rays illuminating a nearby molecular cloud. Then a dedicated XMM-Newton observation led to the discovery of a new X-ray point source spatially coincident with the TeV excess. Two other scenarios were hence proposed to identify the nature of HESS J1832-093. Gamma-rays from inverse Compton radiation in the framework of a pulsar wind nebula scenario or the possibility of gamma-ray production within a binary system are therefore also considered. Deeper multiwavelength observations will help to shed new light on this intriguing VHE source.

INTEGRAL Detection of the First Prompt Gamma-Ray Signal Coincident with the Gravitational-wave Event GW170817

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

Savchenko, V.; Ferrigno, C.; Bozzo, E.

We report the INTernational Gamma-ray Astrophysics Laboratory ( INTEGRAL ) detection of the short gamma-ray burst GRB 170817A (discovered by Fermi -GBM) with a signal-to-noise ratio of 4.6, and, for the first time, its association with the gravitational waves (GWs) from binary neutron star (BNS) merging event GW170817 detected by the LIGO and Virgo observatories. The significance of association between the gamma-ray burst observed by INTEGRAL and GW170817 is 3.2σ, while the association between the Fermi -GBM and INTEGRAL detections is 4.2σ. GRB 170817A was detected by the SPI-ACS instrument about 2 s after the end of the GW event.more » We measure a fluence of (1.4 ± 0.4 ± 0.6) × 10{sup −7} erg cm{sup −2} (75–2000 keV), where, respectively, the statistical error is given at the 1σ confidence level, and the systematic error corresponds to the uncertainty in the spectral model and instrument response. We also report on the pointed follow-up observations carried out by INTEGRAL , starting 19.5 hr after the event, and lasting for 5.4 days. We provide a stringent upper limit on any electromagnetic signal in a very broad energy range, from 3 keV to 8 MeV, constraining the soft gamma-ray afterglow flux to <7.1 × 10{sup −11} erg cm{sup −2} s{sup −1} (80–300 keV). Exploiting the unique capabilities of INTEGRAL , we constrained the gamma-ray line emission from radioactive decays that are expected to be the principal source of the energy behind a kilonova event following a BNS coalescence. Finally, we put a stringent upper limit on any delayed bursting activity, for example, from a newly formed magnetar.« less

GAMMA-RAY OBSERVATIONS OF CYGNUS X-1 ABOVE 100 MeV IN THE HARD AND SOFT STATES

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

Sabatini, S.; Tavani, M.; Del Santo, M.

2013-04-01

We present the results of multi-year gamma-ray observations by the AGILE satellite of the black hole binary system Cygnus X-1. In a previous investigation we focused on gamma-ray observations of Cygnus X-1 in the hard state during the period mid-2007/2009. Here we present the results of the gamma-ray monitoring of Cygnus X-1 during the period 2010/mid-2012 which includes a remarkably prolonged 'soft state' phase (2010 June-2011 May). Previous 1-10 MeV observations of Cyg X-1 in this state hinted at a possible existence of a non-thermal particle component with substantial modifications of the Comptonized emission from the inner accretion disk. Ourmore » AGILE data, averaged over the mid-2010/mid-2011 soft state of Cygnus X-1, provide a significant upper limit for gamma-ray emission above 100 MeV of F{sub soft} < 20 Multiplication-Sign 10{sup -8} photons cm{sup -2} s{sup -1} , excluding the existence of prominent non-thermal emission above 100 MeV during the soft state of Cygnus X-1. We discuss theoretical implications of our findings in the context of high-energy emission models of black hole accretion. We also discuss possible gamma-ray flares detected by AGILE. In addition to a previously reported episode observed by AGILE in 2009 October during the hard state, we report a weak but important candidate for enhanced emission which occurred at the end of 2010 June (2010 June 30 10:00-2010 July 2 10:00 UT) exactly coinciding with a hard-to-soft state transition and before an anomalous radio flare. An appendix summarizes all previous high-energy observations and possible detections of Cygnus X-1 above 1 MeV.« less

Long-term variability of dust optical depths on Mars during MY24-MY32 and their impact on subtropical lower ionosphere: Climatology, modeling, and observations

NASA Astrophysics Data System (ADS)

Sheel, Varun; Haider, S. A.

2016-08-01

Dust optical depths (τ) for nine Martian years (MY24-MY32) in the subtropical region (25-35°S) have been used to classify distinct dust scenarios. These data are based on observations at 9.3 µm from the Mars Global Surveyor and Mars Odyssey missions and encompass the regional dust storms which occur every year around solar longitude (Ls) ~ 220° and the two major dust storms of MY25 and MY28. Constrained by these observations and the Mars Climate Sounder observations of detached dust layers, we estimate altitude profiles of dust concentrations. We discuss the characteristics of dust aerosol particles of different size between 0.2 and 3.0 µm by assuming a modified gamma distribution. We then use a comprehensive ion-dust model to calculate ion densities and conductivities in the lower ionosphere of Mars in the absence of dust storm at τ = 0.1 and Ls = 150° and for three dust storm periods viz., (1) major dust storm at τ = 1.7 and Ls = 210°, (2) major dust storm at τ = 1.2 and Ls = 280°, and (3) regional dust storm at τ = 0.5 and Ls = 220°. The model with 12 neutral species considers galactic cosmic rays as a source of ionization. Results show that the density of the dominant hydrated cluster ions and the electrical conductivity are reduced by an order of magnitude near the surface for a few months until the dust storm settles down to its normal condition.

On the induced gravitational collapse scenario of gamma-ray bursts associated with supernovae

DOE PAGES

Becerra, L.; Bianco, C. L.; Fryer, C. L.; ...

2016-12-10

Following the induced gravitational collapse (IGC) paradigm of gamma-ray bursts (GRBs) associated with type Ib/c supernovae, we present numerical simulations of the explosion of a carbon–oxygen (CO) core in a binary system with a neutron-star (NS) companion. The supernova ejecta trigger a hypercritical accretion process onto the NS thanks to a copious neutrino emission and the trapping of photons within the accretion flow. We show that temperatures of 1–10 MeV develop near the NS surface, hence electron–positron annihilation into neutrinos becomes the main cooling channel leading to accretion rates of 10–9–more » $${10}^{-1}\\,{M}_{\\odot }$$ s–1 and neutrino luminosities of 10 43–10 52 erg s –1 (the shorter the orbital period the higher the accretion rate). We estimate the maximum orbital period, $${P}_{\\max },$$ as a function of the NS initial mass, up to which the NS companion can reach by hypercritical accretion the critical mass for gravitational collapse leading to black hole formation. We then estimate the effects of the accreting and orbiting NS companion onto a novel geometry of the supernova ejecta density profile. We present the results of a $$1.4\\times {10}^{7}$$ particle simulation which show that the NS induces accentuated asymmetries in the ejecta density around the orbital plane. We elaborate on the observables associated with the above features of the IGC process. We apply this framework to specific GRBs: we find that X-ray flashes (XRFs) and binary-driven hypernovae are produced in binaries with $$P\\gt {P}_{\\max }$$ and $$P\\lt {P}_{\\max },$$ respectively. As a result, we analyze in detail the case of XRF 060218.« less

On the Induced Gravitational Collapse Scenario of Gamma-ray Bursts Associated with Supernovae

NASA Astrophysics Data System (ADS)

Becerra, L.; Bianco, C. L.; Fryer, C. L.; Rueda, J. A.; Ruffini, R.

2016-12-01

Following the induced gravitational collapse (IGC) paradigm of gamma-ray bursts (GRBs) associated with type Ib/c supernovae, we present numerical simulations of the explosion of a carbon-oxygen (CO) core in a binary system with a neutron-star (NS) companion. The supernova ejecta trigger a hypercritical accretion process onto the NS thanks to a copious neutrino emission and the trapping of photons within the accretion flow. We show that temperatures of 1-10 MeV develop near the NS surface, hence electron-positron annihilation into neutrinos becomes the main cooling channel leading to accretion rates of 10-9-{10}-1 {M}⊙ s-1 and neutrino luminosities of 1043-1052 erg s-1 (the shorter the orbital period the higher the accretion rate). We estimate the maximum orbital period, {P}\\max , as a function of the NS initial mass, up to which the NS companion can reach by hypercritical accretion the critical mass for gravitational collapse leading to black hole formation. We then estimate the effects of the accreting and orbiting NS companion onto a novel geometry of the supernova ejecta density profile. We present the results of a 1.4× {10}7 particle simulation which show that the NS induces accentuated asymmetries in the ejecta density around the orbital plane. We elaborate on the observables associated with the above features of the IGC process. We apply this framework to specific GRBs: we find that X-ray flashes (XRFs) and binary-driven hypernovae are produced in binaries with P\\gt {P}\\max and P\\lt {P}\\max , respectively. We analyze in detail the case of XRF 060218.

Unusual Black Hole Binary LMC X-3: A Transient High-Mass X-Ray Binary That Is Almost Always On?

NASA Technical Reports Server (NTRS)

Torpin, Trevor J.; Boyd, Patricia T.; Smale, Alan P.; Valencic, Lynne A.

2017-01-01

We have analyzed a rich, multimission, multiwavelength data set from the black hole X-ray binary (BHXB) LMC X-3, covering a new anomalous low state (ALS), during which the source flux falls to an unprecedentedly low and barely detectable level, and a more normal low state. Simultaneous X-ray and UV/optical monitoring data from Swift are combined with pointed observations from the Rossi X-ray Timing Explorer (RXTE) and X-ray Multi- Mirror Mission (XMM-Newton) and light curves from the Monitor of All-Sky X-ray Image (MAXI) instrument to compare the source characteristics during the ALS with those seen during the normal low state. An XMM-Newton spectrum obtained during the ALS can be modeled using an absorbed power law with Gamma = 1.41‚+/- 0.65 and a luminosity of 7.97 x 10(exp 33) erg/s (0.6-5 keV). The Swift X-ray and UV light curves indicate an X-ray lag of approx. 8 days as LMC X-3 abruptly exits the ALS, suggesting that changes in the mass accretion rate from the donor drive the X-ray lag. The normal low state displays an asymmetric profile in which the exit occurs more quickly than the entry, with minimum X-ray flux a factor of approx. 4300 brighter than during the ALS. The UV brightness of LMC X-3 in the ALS is also fainter and less variable than during normal low states. The existence of repeated ALSs in LMC X-3, as well as a comparison with other BHXBs, implies that it is very close to the transient/persistent X-ray source dividing line. We conclude that LMC X-3 is a transient source that is almost always "on."

Imaging Polarimeter for a Sub-MeV Gamma-Ray All-sky Survey Using an Electron-tracking Compton Camera

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

Komura, S.; Takada, A.; Mizumura, Y.

2017-04-10

X-ray and gamma-ray polarimetry is a promising tool to study the geometry and the magnetic configuration of various celestial objects, such as binary black holes or gamma-ray bursts (GRBs). However, statistically significant polarizations have been detected in few of the brightest objects. Even though future polarimeters using X-ray telescopes are expected to observe weak persistent sources, there are no effective approaches to survey transient and serendipitous sources with a wide field of view (FoV). Here we present an electron-tracking Compton camera (ETCC) as a highly sensitive gamma-ray imaging polarimeter. The ETCC provides powerful background rejection and a high modulation factormore » over an FoV of up to 2 π sr thanks to its excellent imaging based on a well-defined point-spread function. Importantly, we demonstrated for the first time the stability of the modulation factor under realistic conditions of off-axis incidence and huge backgrounds using the SPring-8 polarized X-ray beam. The measured modulation factor of the ETCC was 0.65 ± 0.01 at 150 keV for an off-axis incidence with an oblique angle of 30° and was not degraded compared to the 0.58 ± 0.02 at 130 keV for on-axis incidence. These measured results are consistent with the simulation results. Consequently, we found that the satellite-ETCC proposed in Tanimori et al. would provide all-sky surveys of weak persistent sources of 13 mCrab with 10% polarization for a 10{sup 7} s exposure and over 20 GRBs down to a 6 × 10{sup −6} erg cm{sup −2} fluence and 10% polarization during a one-year observation.« less

Imaging Polarimeter for a Sub-MeV Gamma-Ray All-sky Survey Using an Electron-tracking Compton Camera

NASA Astrophysics Data System (ADS)

Komura, S.; Takada, A.; Mizumura, Y.; Miyamoto, S.; Takemura, T.; Kishimoto, T.; Kubo, H.; Kurosawa, S.; Matsuoka, Y.; Miuchi, K.; Mizumoto, T.; Nakamasu, Y.; Nakamura, K.; Oda, M.; Parker, J. D.; Sawano, T.; Sonoda, S.; Tanimori, T.; Tomono, D.; Yoshikawa, K.

2017-04-01

X-ray and gamma-ray polarimetry is a promising tool to study the geometry and the magnetic configuration of various celestial objects, such as binary black holes or gamma-ray bursts (GRBs). However, statistically significant polarizations have been detected in few of the brightest objects. Even though future polarimeters using X-ray telescopes are expected to observe weak persistent sources, there are no effective approaches to survey transient and serendipitous sources with a wide field of view (FoV). Here we present an electron-tracking Compton camera (ETCC) as a highly sensitive gamma-ray imaging polarimeter. The ETCC provides powerful background rejection and a high modulation factor over an FoV of up to 2π sr thanks to its excellent imaging based on a well-defined point-spread function. Importantly, we demonstrated for the first time the stability of the modulation factor under realistic conditions of off-axis incidence and huge backgrounds using the SPring-8 polarized X-ray beam. The measured modulation factor of the ETCC was 0.65 ± 0.01 at 150 keV for an off-axis incidence with an oblique angle of 30° and was not degraded compared to the 0.58 ± 0.02 at 130 keV for on-axis incidence. These measured results are consistent with the simulation results. Consequently, we found that the satellite-ETCC proposed in Tanimori et al. would provide all-sky surveys of weak persistent sources of 13 mCrab with 10% polarization for a 107 s exposure and over 20 GRBs down to a 6 × 10-6 erg cm-2 fluence and 10% polarization during a one-year observation.

High-energy emission from the eclipsing millisecond pulsar PSR 1957+20

NASA Technical Reports Server (NTRS)

Arons, Jonathan; Tavani, Marco

1993-01-01

The properties of the high-energy emission expected from the eclipsing millisecond pulsar system PSR 1957+20 are investigated. Emission is considered by both the relativistic shock produced by the pulsar wind in the nebula surrounding the binary and by the shock constraining the mass outflow from the companion star of PSR 1957+20. On the basis of the results of microscopic plasma physical models of relativistic shocks it is suggested that the high-energy radiation is produced in the range from X-rays to MeV gamma rays in the binary and in the range from 0.01 eV to about 40 keV in the nebula. Doppler boost of the emission in the radiating wind suggests the flux should vary on the orbital time scale, with the largest flux observed roughly coincident with the pulsar's radio eclipse.

Discovery of the Orbit of the X-ray pulsar OAO 1657-415

NASA Technical Reports Server (NTRS)

Chakrabarty, Deepto; Grunsfeld, John M.; Prince, Thomas A.; Bildsten, Lars; Finger, Mark H.; Wilson, Robert B.; Fishman, Gerald J.; Meegan, Charles A.; Paciesas, William S.

1993-01-01

Timing observations of the 38 s accreting X-ray pulsar OAO 1657-415 made with the BATSE large-area detectors on the Compton Gamma Ray Observatory have revealed a binary orbit with an X-ray eclipse by the stellar companion. From the pulsar mass function fx(M) = 11.7 +/- 0.2 solar masses and the measured eclipse half-angle theta(e) = 29.7 +/- 1.3 deg, we infer that the stellar companion is a supergiant of spectral class B0-B6. If the companion can be identified and its orbital velocity measured, the neutron star mass can be constrained. Both intrinsic spin-up and spin-down of the pulsar were measured during our observation.

High statistics search for ultrahigh energy {gamma}-ray emission from Cygnus X-3 and Hercules X-1

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

Borione, A.; Chantell, M.C.; Covault, C.E.

1997-02-01

We have carried out a high statistics (2{times}10{sup 9} events) search for ultrahigh energy {gamma}-ray emission from the x-ray binary sources Cygnus X-3 and Hercules X-1. Using data taken with the CASA-MIA detector over a five year period (1990{endash}1995), we find no evidence for steady emission from either source. The derived 90{percent} C.L. upper limit to the steady integral flux of {gamma} rays from Cygnus X-3 is {Phi}(E{gt}115TeV){lt}6.3{times}10{sup {minus}15} photons cm{sup {minus}2}sec{sup {minus}1}, and from Hercules X-1 it is {Phi}(E{gt}115TeV){lt}8.5{times}10{sup {minus}15} photonscm{sup {minus}2}sec{sup {minus}1}. These limits are more than two orders of magnitude lower than earlier claimed detections and aremore » better than recent experiments operating in the same energy range. We have also searched for transient emission on time periods of one day and 0.5 h and find no evidence for such emission from either source. The typical daily limit on the integral {gamma}-ray flux from Cygnus X-3 or Hercules X-1 is {Phi}{sub daily}(E{gt}115TeV){lt}2.0{times}10{sup {minus}13} photons cm{sup {minus}2}sec{sup {minus}1}. For Cygnus X-3, we see no evidence for emission correlated with the 4.8 h x-ray periodicity or with the occurrence of large radio flares. Unless one postulates that these sources were very active earlier and are now dormant, the limits presented here put into question the earlier results, and highlight the difficulties that possible future experiments will have in detecting {gamma}-ray signals at ultrahigh energies. {copyright} {ital 1997} {ital The American Physical Society}« less

Search for an X-ray identification of a strong gamma-ray source. [sas-3 observations

NASA Technical Reports Server (NTRS)

Lamb, R. C.

1979-01-01

X-rays from Cygnus X-3 were observed during early 1978 with the detectors of the SAS-3 satellite. These observations in conjunction with earlier UHURU and ANS data indicate that the 4.8 hr period of Cygnus X-3 is increasing at the rate of P/P = (5/1 plus or minus 1.3) x 10 to the minus 6 power/1 yr. The sign and magnitude for this change are incompatible with a rotation model for the period and are in reasonable agreement with model predictions for orbital changes associated with mass loss and transfer in a binary system.

Pulsar-irradiated stars in dense globular clusters

NASA Technical Reports Server (NTRS)

Tavani, Marco

1992-01-01

We discuss the properties of stars irradiated by millisecond pulsars in 'hard' binaries of dense globular clusters. Irradiation by a relativistic pulsar wind as in the case of the eclipsing millisecond pulsar PSR 1957+20 alter both the magnitude and color of the companion star. Some of the blue stragglers (BSs) recently discovered in dense globular clusters can be irradiated stars in binaries containing powerful millisecond pulsars. The discovery of pulsar-driven orbital modulations of BS brightness and color with periods of a few hours together with evidence for radio and/or gamma-ray emission from BS binaries would valuably contribute to the understanding of the evolution of collapsed stars in globular clusters. Pulsar-driven optical modulation of cluster stars might be the only observable effect of a new class of binary pulsars, i.e., hidden millisecond pulsars enshrouded in the evaporated material lifted off from the irradiated companion star.

The Advanced Gamma-ray Imaging System (AGIS)

NASA Astrophysics Data System (ADS)

Buckley, James

2008-04-01

We describe a concept for a ˜km^2 ground-based gamma-ray experiment (AGIS) comprised of an array of ˜100 imaging atmospheric Cherenkov telescopes achieving a sensitivity an order of magnitude better than the current generation of space or ground-based instruments in the energy range of 40 GeV to ˜100 TeV. We present the scientific drivers for AGIS including the prospects for contributions to understanding extragalactic sources such as nearby galaxies, active galaxies, galaxy clusters and GRB; galactic sources such as X-ray binaries, supernova remnants, and pulsar wind nebulae; as well as probes of fundamental physics including indirectly detecting dark matter and probing TeV-scale physics. With the current generation of atmospheric Cherenkov telescope arrays, TeV astronomy has become well established, with the number TeV gamma-ray sources now nearing 100, including many unidentified and serendipitous sources. Improvements in the instantaneous field of view, angular resolution, effective area and energy resolution of AGIS are certain to provide great scientific returns in high energy astrophysics as well as opening up new discovery space. Here we present an overview of the ongoing design studies for AGIS including the optimization of array parameters as well as an overview of the technical drivers for the observatory.

GX 3+1: THE STABILITY OF SPECTRAL INDEX AS A FUNCTION OF MASS ACCRETION RATE

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

Seifina, Elena; Titarchuk, Lev, E-mail: seif@sai.msu.ru, E-mail: titarchuk@fe.infn.it, E-mail: lev@milkyway.gsfc.nasa.gov

2012-03-10

We present an analysis of the spectral and timing properties observed in X-rays from neutron star (NS) binary GX 3+1 (4U 1744-26) during long-term transitions between the faint and bright phases superimposed on short-term transitions between lower banana (LB) and upper banana (UB) branches in terms of its color-color diagram. We analyze all observations of this source obtained with the Rossi X-ray Timing Explorer and Beppo SAX satellites. We find that the X-ray broadband energy spectra during these spectral transitions can be adequately reproduced by a composition of a low-temperature blackbody component, a Comptonized component (COMPTB), and a Gaussian component.more » We argue that the electron temperature kT{sub e} of the Compton cloud monotonically increases from 2.3 keV to 4.5 keV, when GX 3+1 makes a transition from UB to LB. We also detect an evolution of noise components (a very low frequency noise and a high-frequency noise) during these LB-UB transitions. Using a disk seed photon normalization of COMPTB, which is proportional to the mass accretion rate, we find that the photon power-law index {Gamma} is almost constant ({Gamma} = 2.00 {+-} 0.02) when mass accretion rate changes by a factor of four. In addition, we find that the emergent spectrum is dominated by the strong Comptonized component. We interpret this quasi-stability of the index {Gamma} and a particular form of the spectrum in the framework of a model in which the energy release in the transition layer located between the accretion disk and NS surface dominates that in the disk. Moreover, this index stability effect now established for GX 3+1 was previously found in the atoll source 4U 1728-34 and suggested for a number of other low-mass X-ray NS binaries (see Farinelli and Titarchuk). This intrinsic behavior of NSs, in particular for atoll sources, is fundamentally different from that seen in black hole binary sources where the index monotonically increases during spectral transition from the low state to the high state and then finally saturates at high values of mass accretion rate.« less

Search for very high-energy gamma-ray emission from the microquasar Cygnus X-1 with the MAGIC telescopes

NASA Astrophysics Data System (ADS)

Ahnen, M. L.; Ansoldi, S.; Antonelli, L. A.; Arcaro, C.; Babić, A.; Banerjee, B.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; Bednarek, W.; Bernardini, E.; Berti, A.; Bhattacharyya, W.; Biasuzzi, B.; Biland, A.; Blanch, O.; Bonnefoy, S.; Bonnoli, G.; Carosi, R.; Carosi, A.; Chatterjee, A.; Colin, P.; Colombo, E.; Contreras, J. L.; Cortina, J.; Covino, S.; Cumani, P.; da Vela, P.; Dazzi, F.; de Angelis, A.; de Lotto, B.; de Oña Wilhelmi, E.; di Pierro, F.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher Glawion, D.; Elsaesser, D.; Engelkemeier, M.; Fallah Ramazani, V.; Fernández-Barral, A.; Fidalgo, D.; Fonseca, M. V.; Font, L.; Fruck, C.; Galindo, D.; García López, R. J.; Garczarczyk, M.; Gaug, M.; Giammaria, P.; Godinović, N.; Gora, D.; Guberman, D.; Hadasch, D.; Hahn, A.; Hassan, T.; Hayashida, M.; Herrera, J.; Hose, J.; Hrupec, D.; Ishio, K.; Konno, Y.; Kubo, H.; Kushida, J.; Kuveždić, D.; Lelas, D.; Lindfors, E.; Lombardi, S.; Longo, F.; López, M.; Maggio, C.; Majumdar, P.; Makariev, M.; Maneva, G.; Manganaro, M.; Mannheim, K.; Maraschi, L.; Mariotti, M.; Martínez, M.; Mazin, D.; Menzel, U.; Minev, M.; Mirzoyan, R.; Moralejo, A.; Moreno, V.; Moretti, E.; Neustroev, V.; Niedzwiecki, A.; Nievas Rosillo, M.; Nilsson, K.; Ninci, D.; Nishijima, K.; Noda, K.; Nogués, L.; Paiano, S.; Palacio, J.; Paneque, D.; Paoletti, R.; Paredes, J. M.; Paredes-Fortuny, X.; Pedaletti, G.; Peresano, M.; Perri, L.; Persic, M.; Prada Moroni, P. G.; Prandini, E.; Puljak, I.; Garcia, J. R.; Reichardt, I.; Rhode, W.; Ribó, M.; Rico, J.; Righi, C.; Saito, T.; Satalecka, K.; Schroeder, S.; Schweizer, T.; Sitarek, J.; Šnidarić, I.; Sobczynska, D.; Stamerra, A.; Strzys, M.; Surić, T.; Takalo, L.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Torres, D. F.; Torres-Albà, N.; Treves, A.; Vanzo, G.; Vazquez Acosta, M.; Vovk, I.; Ward, J. E.; Will, M.; Zarić, D.; MAGIC Collaboration; Bosch-Ramon, V.; Pooley, G. G.; Trushkin, S. A.; Zanin, R.

2017-12-01

The microquasar Cygnus X-1 displays the two typical soft and hard X-ray states of a black hole transient. During the latter, Cygnus X-1 shows a one-sided relativistic radio-jet. Recent detection of the system in the high energy (HE; E ≳ 60 MeV) gamma-ray range with Fermi-LAT associates this emission with the outflow. Former MAGIC observations revealed a hint of flaring activity in the very high-energy (VHE; E ≳ 100 GeV) regime during this X-ray state. We analyse ∼97 h of Cygnus X-1 data taken with the MAGIC telescopes between July 2007 and October 2014. To shed light on the correlation between hard X-ray and VHE gamma rays as previously suggested, we study each main X-ray state separately. We perform an orbital phase-folded analysis to look for variability in the VHE band. Additionally, to place this variability behaviour in a multiwavelength context, we compare our results with Fermi-LAT, AGILE, Swift-BAT, MAXI, RXTE-ASM, AMI and RATAN-600 data. We do not detect Cygnus X-1 in the VHE regime. We establish upper limits for each X-ray state, assuming a power-law distribution with photon index Γ = 3.2. For steady emission in the hard and soft X-ray states, we set integral upper limits at 95 per cent confidence level for energies above 200 GeV at 2.6 × 10-12 photons cm-2 s-1 and 1.0 × 10-11 photons cm-2 s-1, respectively. We rule out steady VHE gamma-ray emission above this energy range, at the level of the MAGIC sensitivity, originating in the interaction between the relativistic jet and the surrounding medium, while the emission above this flux level produced inside the binary still remains a valid possibility.

Fermi establishes classical novae as a distinct class of gamma-ray sources

DOE PAGES

Cheung, C. C.

2014-07-31

A classical nova results from runaway thermonuclear explosions on the surface of a white dwarf that accretes matter from a low-mass main-sequence stellar companion. In 2012 and 2013, three novae were detected in γ rays and stood in contrast to the first γ-ray detected nova V407 Cygni 2010, which belongs to a rare class of symbiotic binary systems. Despite likely differences in the compositions and masses of their white dwarf progenitors, the three classical novae are similarly characterized as soft spectrum transient γ-ray sources detected over 2-3 week durations. The γ-ray detections point to unexpected high-energy particle acceleration processes linkedmore » to the mass ejection from thermonuclear explosions in an unanticipated class of Galactic γ-ray sources.« less

Discovery of Rapidly Moving Partial X-Ray Absorbers Within Cassiopeiae

NASA Technical Reports Server (NTRS)

Hamaguchi, K.; Oskinova, L.; Russell, C. M. P.; Petre, R.; Enoto, T.; Morihana, K.; Ishida, M.

2016-01-01

Gamma Cassiopeiae is an enigmatic Be star with unusually strong hard X-ray emission. The Suzaku observatory detected six rapid X-ray spectral hardening events called "softness dips" in a approx.100 ks observation in 2011. All the softness dip events show symmetric softness-ratio variations, and some of them have flat bottoms apparently due to saturation. The softness dip spectra are best described by either approx.40% or approx.70% partial covering absorption to kT approx.12 keV plasma emission by matter with a neutral hydrogen column density of approx.(2-8) ×10(exp 21)/sq cm, while the spectrum outside these dips is almost free of absorption. This result suggests the presence of two distinct X-ray-emitting spots in the gamma Cas system, perhaps on a white dwarf (WD) companion with dipole mass accretion. The partial covering absorbers may be blobs in the Be stellar wind, the Be disk, or rotating around the WD companion. Weak correlations of the softness ratios to the hard X-ray flux suggest the presence of stable plasmas at kT approx 0.9 and 5 keV, which may originate from the Be or WD winds. The formation of a Be star and WD binary system requires mass transfer between two stars; gamma Cas may have experienced such activity in the past.

X-ray diffraction and reflectivity validation of the depletion attraction in the competitive adsorption of lung surfactant and albumin.

PubMed

Stenger, Patrick C; Wu, Guohui; Miller, Chad E; Chi, Eva Y; Frey, Shelli L; Lee, Ka Yee C; Majewski, Jaroslaw; Kjaer, Kristian; Zasadzinski, Joseph A

2009-08-05

Lung surfactant (LS) and albumin compete for the air-water interface when both are present in solution. Equilibrium favors LS because it has a lower equilibrium surface pressure, but the smaller albumin is kinetically favored by faster diffusion. Albumin at the interface creates an energy barrier to subsequent LS adsorption that can be overcome by the depletion attraction induced by polyethylene glycol (PEG) in solution. A combination of grazing incidence x-ray diffraction (GIXD), x-ray reflectivity (XR), and pressure-area isotherms provides molecular-resolution information on the location and configuration of LS, albumin, and polymer. XR shows an average electron density similar to that of albumin at low surface pressures, whereas GIXD shows a heterogeneous interface with coexisting LS and albumin domains at higher surface pressures. Albumin induces a slightly larger lattice spacing and greater molecular tilt, similar in effect to a small decrease in the surface pressure. XR shows that adding PEG to the LS-albumin subphase restores the characteristic LS electron density profile at the interface, and confirms that PEG is depleted near the interface. GIXD shows the same LS Bragg peaks and Bragg rods as on a pristine interface, but with a more compact lattice corresponding to a small increase in the surface pressure. These results confirm that albumin adsorption creates a physical barrier that inhibits LS adsorption, and that PEG in the subphase generates a depletion attraction between the LS aggregates and the interface that enhances LS adsorption without substantially altering the structure or properties of the LS monolayer.

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.

Searching the Gamma-Ray Sky for Counterparts to Gravitational Wave Sources Fermi Gamma-Ray Burst Monitor and Large Area Telescope Observations of LVT151012 and GW151226

NASA Technical Reports Server (NTRS)

Racusin, J. L.; Burns, E.; Goldstein, A.; Connaughton, V.; Wilson-Hodge, C. A.; Jenke, P.; Blackburn, L.; Briggs, M. S.; Broida, J.; Camp, J.;

Searching the Gamma-Ray Sky for Counterparts to Gravitational Wave Sources: FERMI Gamma Ray Burst MONITO R and Large Area Telescope Observations of LVT151012 and GW151226

DOE PAGES

Racusin, J. L.; Burns, E.; Goldstein, A.; ...

2017-01-19

Here, we present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candidate LVT151012. At the time of the LIGO triggers on LVT151012 and GW151226, GBM was observing 68% and 83% of the localization regions, and LAT was observing 47% and 32%, respectively. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for characterizing the flux upper boundsmore » across large areas of the sky. Finally, due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, differences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914.« less

SEARCHING THE GAMMA-RAY SKY FOR COUNTERPARTS TO GRAVITATIONAL WAVE SOURCES: FERMI GAMMA-RAY BURST MONITO R AND LARGE AREA TELESCOPE OBSERVATIONS OF LVT151012 AND GW151226

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

Racusin, J. L.; Camp, J.; Singer, L.

2017-01-20

We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candidate LVT151012. At the time of the LIGO triggers on LVT151012 and GW151226, GBM was observing 68% and 83% of the localization regions, and LAT was observing 47% and 32%, respectively. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for characterizing the flux upper bounds acrossmore » large areas of the sky. Due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, differences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914.« less

Variability in the high energy gamma ray emission from Cyg X-3 over a two-year period (1983 - 1984) at E 4 x 10(11) eV

NASA Technical Reports Server (NTRS)

Cawley, M. F.; Fegan, D. J.; Gibbs, K.; Gorham, P. W.; Lamb, R. C.; Liebing, D. F.; Porter, N. A.; Stenger, V. J.; Weekes, T. C.; Williams, R. J.

1985-01-01

Cygnus X-3 is observed to emit gamma rays with energies in excess of 4 x 10 to the 11th power eV during two out of 9 observational categories over an 18 month time span. The emissions are observed at the 0.6 phase of the characteristic 4.8 hr light curve for this binary system. We estimate a peak flux at phase 0.6 of 5 x 10 to the minus 10th power photons cm-2s-1 at a software threshold of 8 x 10 to the 11th power eV for Oct/Nov 1983. A flux for the June 84 effect cannot be reliably calculated at present due to lack of Monte Carlo simulations for the energy range and spectral region. For the other 7 observational categories the observations are consistent with zero source emission. The light curve would appear to be variable on a time scale of a couple of weeks at these categories. Selection of compact images in accordance with Monte Carlo simulations combined with empirical optimization techniques have led to an enriched gamma ray light curve for the Oct/Nov 1983 data. Selection on the basis of shower orientation, however, has not led to any notable enhancement of the gamma ray content. Individual Cherenko images can be reliably sorted on an event by event basis into either proton-induced or photon-induced showers.

DO THE FERMI GAMMA-RAY BURST MONITOR AND SWIFT BURST ALERT TELESCOPE SEE THE SAME SHORT GAMMA-RAY BURSTS?

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

Burns, Eric; Briggs, Michael S.; Connaughton, Valerie

2016-02-20

Compact binary system mergers are expected to generate gravitational radiation detectable by ground-based interferometers. A subset of these, the merger of a neutron star with another neutron star or a black hole, are also the most popular model for the production of short gamma-ray bursts (GRBs). The Swift Burst Alert Telescope (BAT) and the Fermi Gamma-ray Burst Monitor (GBM) trigger on short GRBs (SGRBs) at rates that reflect their relative sky exposures, with the BAT detecting 10 per year compared to about 45 for GBM. We examine the SGRB populations detected by Swift BAT and Fermi GBM. We find thatmore » the Swift BAT triggers on weaker SGRBs than Fermi GBM, providing they occur close to the center of the BAT field of view, and that the Fermi GBM SGRB detection threshold remains flatter across its field of view. Overall, these effects combine to give the instruments the same average sensitivity, and account for the SGRBs that trigger one instrument but not the other. We do not find any evidence that the BAT and GBM are detecting significantly different populations of SGRBs. Both instruments can detect untriggered SGRBs using ground searches seeded with time and position. The detection of SGRBs below the on-board triggering sensitivities of Swift BAT and Fermi GBM increases the possibility of detecting and localizing the electromagnetic counterparts of gravitational wave (GW) events seen by the new generation of GW detectors.« less

A NuSTAR OBSERVATION OF THE GAMMA-RAY-EMITTING X-RAY BINARY AND TRANSITIONAL MILLISECOND PULSAR CANDIDATE 1RXS J154439.4–112820

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

Bogdanov, Slavko

I present a 40 ks Nuclear Spectroscopic Telescope Array observation of the recently identified low-luminosity X-ray binary and transitional millisecond pulsar (tMSP) candidate 1RXS J154439.4 112820, which is associated with the high-energy γ -ray source 3FGL J1544.6 1125. The system is detected up to ∼30 keV with an extension of the same power-law spectrum and rapid large-amplitude variability between two flux levels observed in soft X-rays. These findings provide further evidence that 1RXS J154439.4 112820 belongs to the same class of objects as the nearby bona fide tMSPs PSR J1023+0038 and XSS J12270 4859 and therefore almost certainly hosts amore » millisecond pulsar accreting at low luminosity. I also examine the long-term accretion history of 1RXS J154439.4 112820 based on archival optical, ultraviolet, X-ray, and γ -ray light curves covering approximately the past decade. Throughout this period, the source has maintained similar flux levels at all wavelengths, which is an indication that it has not experienced prolonged episodes of a non-accreting radio pulsar state but may spontaneously undergo such events in the future.« less

Spectral State Evolution of 4U 1820-30: the Stability of the Spectral Index of Comptonization Tail

NASA Technical Reports Server (NTRS)

Titarchuk, Lev G.; Seifina, Elena; Frontera, Filippo

2013-01-01

We analyze the X-ray spectra and their timing properties of the compact Xray binary 4U 1820-30. We establish spectral transitions in this source seen with BeppoSAX and the Rossi X-ray Timing Explorer (RXTE). During the RXTE observations (1996 - 2009), the source were approximately approximately 75% of its time in the soft state making the lower banana and upper banana transitions combined with long-term low-high state transitions. We reveal that all of the X-ray spectra of 4U 1820-30 are fit by a composition of a thermal (blackbody) component, a Comptonization component (COMPTB) and a Gaussian-line component. Thus using this spectral analysis we find that the photon power-law index Gamma of the Comptonization component is almost unchangeable (Gamma approximately 2) while the electron temperature kTe changes from 2.9 to 21 keV during these spectral events. We also establish that for these spectral events the normalization of COMPTB component (which is proportional to mass accretion rate ?M) increases by factor 8 when kTe decreases from 21 keV to 2.9 keV. Before this index stability effect was also found analyzing X-ray data for Z-source GX 340+0 and for atolls, 4U 1728-34, GX 3+1. Thus, we can suggest that this spectral stability property is a spectral signature of an accreting neutron star source. On the other hand in a black hole binary G monotonically increases with ?Mand ultimately its value saturates at large ?M.

Multi-wavelength studies of Redback and Black Widow pulsars

NASA Astrophysics Data System (ADS)

Mignani, Roberto; Salvetti, David; Pallanca, Cristina; Marelli, Martino; De Luca, Andrea; Belfiore, Andrea Mario

2016-07-01

The unexpected Fermi discovery of more than 70 gamma-ray milli-second pulsars (MSPs) outside globular clusters, spurred the scientific interest on these objects, and opened new horizons in MSP astronomy and on the study of the evolution of neutron stars in compact binary systems, including the ablation process of the companion star in the so-called Black Widow (BW) and Redback (RB) systems. It is thought that an important fraction of the tens of unidentified pulsar-like Fermi sources at high latitude are MSPs, yet unidentified, owing to their extremely elusive radio emission. As shown in a few recent cases, optical observations have been instrumental to spot binary MSP candidates through the discovery of periodic modulations in the flux of their putative companions. In this contribution, we report on the recent follow-ups of several candidate binary MSPs carried out with optical and X-ray facilities, e.g. GROND and XMM-Newton, Swift. This program already lead to identification of the Fermi source 3FGL 2036.6-5618 as candidate RB system, through the detection of periodic (orbital) modulation of its X/optical flux (Salvetti et al. 2015).

A short gamma-ray burst apparently associated with an elliptical galaxy at redshift z = 0.225.

PubMed

Gehrels, N; Sarazin, C L; O'Brien, P T; Zhang, B; Barbier, L; Barthelmy, S D; Blustin, A; Burrows, D N; Cannizzo, J; Cummings, J R; Goad, M; Holland, S T; Hurkett, C P; Kennea, J A; Levan, A; Markwardt, C B; Mason, K O; Meszaros, P; Page, M; Palmer, D M; Rol, E; Sakamoto, T; Willingale, R; Angelini, L; Beardmore, A; Boyd, P T; Breeveld, A; Campana, S; Chester, M M; Chincarini, G; Cominsky, L R; Cusumano, G; de Pasquale, M; Fenimore, E E; Giommi, P; Gronwall, C; Grupe, D; Hill, J E; Hinshaw, D; Hjorth, J; Hullinger, D; Hurley, K C; Klose, S; Kobayashi, S; Kouveliotou, C; Krimm, H A; Mangano, V; Marshall, F E; McGowan, K; Moretti, A; Mushotzky, R F; Nakazawa, K; Norris, J P; Nousek, J A; Osborne, J P; Page, K; Parsons, A M; Patel, S; Perri, M; Poole, T; Romano, P; Roming, P W A; Rosen, S; Sato, G; Schady, P; Smale, A P; Sollerman, J; Starling, R; Still, M; Suzuki, M; Tagliaferri, G; Takahashi, T; Tashiro, M; Tueller, J; Wells, A A; White, N E; Wijers, R A M J

2005-10-06

Gamma-ray bursts (GRBs) come in two classes: long (> 2 s), soft-spectrum bursts and short, hard events. Most progress has been made on understanding the long GRBs, which are typically observed at high redshift (z approximately 1) and found in subluminous star-forming host galaxies. They are likely to be produced in core-collapse explosions of massive stars. In contrast, no short GRB had been accurately (< 10'') and rapidly (minutes) located. Here we report the detection of the X-ray afterglow from--and the localization of--the short burst GRB 050509B. Its position on the sky is near a luminous, non-star-forming elliptical galaxy at a redshift of 0.225, which is the location one would expect if the origin of this GRB is through the merger of neutron-star or black-hole binaries. The X-ray afterglow was weak and faded below the detection limit within a few hours; no optical afterglow was detected to stringent limits, explaining the past difficulty in localizing short GRBs.

The signature of supernova ejecta in the X-ray afterglow of the gamma-ray burst 011211.

PubMed

Reeves, J N; Watson, D; Osborne, J P; Pounds, K A; O'Brien, P T; Short, A D T; Turner, M J L; Watson, M G; Mason, K O; Ehle, M; Schartel, N

2002-04-04

Now that gamma-ray bursts (GRBs) have been determined to lie at cosmological distances, their isotropic burst energies are estimated to be as high as 1054 erg (ref. 2), making them the most energetic phenomena in the Universe. The nature of the progenitors responsible for the bursts remains, however, elusive. The favoured models range from the merger of two neutron stars in a binary system to the collapse of a massive star. Spectroscopic studies of the afterglow emission could reveal details of the environment of the burst, by indicating the elements present, the speed of the outflow and an estimate of the temperature. Here we report an X-ray spectrum of the afterglow of GRB011211, which shows emission lines of magnesium, silicon, sulphur, argon, calcium and possibly nickel, arising in metal-enriched material with an outflow velocity of the order of one-tenth the speed of light. These observations strongly favour models where a supernova explosion from a massive stellar progenitor precedes the burst event and is responsible for the outflowing matter.

Neutron-Star Merger Detected By Many Eyes and Ears

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2017-10-01

Where were you on Thursday, 17 August 2017? I was in Idaho, getting ready for Monday mornings solar eclipse. What I didnt know was that, at the time, around 70 teams around the world were mobilizing to point their ground- and space-based telescopes at a single patch of sky suspected to host the first gravitational-wave-detected merger of two neutron stars.Sudden Leaps for ScienceThe masses for black holes detected through electromagnetic observations (purple), black holes measured by gravitational-wave observations (blue), neutron stars measured with electromagnetic observations (yellow), and the neutron stars that merged in GW170817 (orange). [LIGO-Virgo/Frank Elavsky/NorthwesternUniversity]The process of science is long and arduous, generally occurring at a slow plod as theorists make predictions, and observations are then used to chip away at these theories, gradually confirming or disproving them. It is rare that science progresses forward in a giant leap, with years upon years of theories confirmed in one fell swoop.14 September 2015 marked the day of one such leap, as the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected gravitational waves for the first time simultaneously verifying that black holes exist, that black-hole binaries exist, and that they can merge on observable timescales, emitting signals that directly confirm the predictions of general relativity.As it turns out, 17 August 2017 was another such day. On this day, LIGO observed a gravitational-wave signal unlike its previous black-hole detections. Instead, this was a signal consistent with the merger of two neutron stars.Artists illustrations of the stellar-merger model for short gamma-ray bursts. In the model, 1) two neutron stars inspiral, 2) they merge and produce a gamma-ray burst, 3) a small fraction of their mass is flung out and radiates as a kilonova, 4) a massive neutron star or black hole with a disk remains after the event. [NASA, ESA, and A. Feild (STScI)]What We PredictedTheoretical models describing the merger of two compact objects predict a chirping gravitational-wave signal as the objects spiral closer and closer. Unlike in a black-hole merger, however, the end of the chirp from merging neutron stars should coincide with a phenomenon known as a short gamma-ray burst: a powerful storm of energetic gamma rays produced as the objects finally collide.According to the models, these gravitational waves and gamma rays will be followed by a kilonova a transient source visible in infrared, optical, and ultraviolet which arises from radioactive decay of heavy elements formed in the collision. This source should gradually decay over a timescale of weeks.Lastly, the merger could create a powerful jet of high-energy particles, which could be visible to us in X-ray and radio wavelengths as it is emitted and interacts with its surrounding environment. We could also detect neutrinos from this outflow.What We Saw (and Didnt See)The localization of the gravitational-wave, gamma-ray, and optical signals of the neutron-star merger detected on 17 August, 2017. [Abbott et al. 2017]So what did we see on 17 August, 2017 and thereafter? Heres what was found by the army of collaborations searching in gravitational waves, electromagnetic signals across the spectrum, and neutrinos:Gravitational WavesThe gravitational-wave signature of a binary neutron-star merger was observed with all three gravitational-wave detectors currently operating as a part of the LIGO-Virgo collaboration. GW170817s signal was in the sensitivity band of these detectors for 100 seconds, arriving first at the Virgo detector in Italy, next at LIGO-Livingston in Louisiana 22 milliseconds later, and finally at LIGO-Hanford in Washington 3 milliseconds after that. These detections localized the source to a region of 31 square degrees at a relatively nearby distance of 130 million light-years, and they identified the binary components to be neutron stars.Gamma-Ray BurstThe Fermi Gamma-Ray Burst Monitor detected a short ( 2-second) gamma-ray burst, GRB170817A, which appears to have occurred 1.7 seconds after the merger indicated by the gravitational-wave signal. This source was later identified by the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) spacecraft as well.Locations of the many observatories that observed the neutron-star merger first detected on 17 August, 2017. [Abbott et al. 2017]Electromagnetic Counterpart and Host GalaxyThough they were initially foiled by the signals location (the localized region of GW170817 only became visible in Chile 10 hours after its detection), the One-Meter, Two-Hemisphere team used the Swope telescope at Las Campanas Observatory in Chile to discover an optical counterpart to the LIGO and Fermi detection, located in the early-type galaxy NGC 4993. Within an hour, five other teams had independently detected the optical source in NGC 4993, with more following after.In the subsequent hours, days, and weeks, observatories across the electromagnetic spectrum monitored the transient. The source soon faded from view in the ultraviolet and gradually reddened in the optical and infrared bands. Delayed X-ray emission was discovered 9 days after the LIGO signal, and a radio counterpart was discovered a week after that.No NeutrinosThough several neutrino observatories searched for high-energy neutrinos in the direction of NGC 4993 in the two-week period following the merger, none were detected.Summary and timeline of the observations of the neutron-star merger detected on 17 August, 2017 relative to the time tc of the gravitational-wave event. Click for a closer look. [Abbott et al. 2017]A Spectacular ConfirmationSo what do these observations tell us? Our model for neutron-star mergers appears to be remarkably successful! The associated detections of gravitational waves and electromagnetic counterparts have confirmed that merging neutron stars produce the expected gravitational-wave signal, that they are the source of gamma-ray bursts, that some of the heaviest elements in the universe are produced during the collision of these stars, and that jets of high-energy particles are created that subsequently interact with their environment.As with any interesting scientific discovery, new points of exploration have arisen we can now wonder why the gamma-ray burst was unusually weak given its close distance, for instance, or why we didnt detect any neutrinos from the outflow.In spite of our new questions, the combination of these recent discoveries provide a resounding verification of our understanding of how compact objects merge. The various signals that began on 17 August, 2017 have simultaneously confirmed a stack of carefully constructed theories that were crafted over decades to explain how seemingly unrelated electromagnetic signals might all tie together. Its a beautiful thing when science works out this well!For more information, check out the ApJL Focus Issue on this result here:Focus on The Electromagnetic Counterpart of the Neutron Star Binary Merger GW170817 CitationAbbott, B.P. et al 2017 ApJL 848 L12. doi:10.3847/2041-8213/aa91c9

Properties of Supergiant Fast X-Ray Transients as Observed by Swift

NASA Technical Reports Server (NTRS)

Romano, P.; Vercellone, S.; Krimm, H. A.; Esposito, P.; Cusumano, C.; LaParola, V.; Mangano, V.; Kennea, J. A.; Burrows, D. N.; Pagani, C.;

The exotic remnants of compact object binary mergers

NASA Astrophysics Data System (ADS)

Duez, Matthew

2017-01-01

The collision and merger of a neutron star with a black hole or another neutron star is a strong source of gravitational waves and a promising setup for the creation of bright infrared (kilonova) and gamma ray (gamma ray burst) transients. These violent events can be modeled by numerical simulations incorporating general relativity, fluid dynamics, and nuclear physics. In this talk, I will explain the findings of some of these simulations. Depending on the properties of the binary, the merger leaves a black hole, a black hole accreting matter from a torus at an incredible rate, or a massive spinning neutron star. The latter two cases are characterized by the importance of differential rotation, magnetohydrodynamic processes, and neutrino radiation. To understand these systems, I will focus on what we know of their dynamical and thermal equilibrium structure, what we know of the dynamical instabilities to which they might be prone, and what we can tentatively say about their subsequent secular evolution from outflow, magnetic, radiative, and other effects. Computer simulations are becoming ever more impressive but remain unequal to the problem at hand, so I will address the challenges still posed by small-scale magnetohydrodynamic effects and by radiation transport. The author is a member of the SXS Collaboration and acknowledges support from NSF.

X-rays and gamma-rays from accretion flows onto black holes in Seyferts and X-ray binaries

NASA Technical Reports Server (NTRS)

Zdziarski, Andrzej A.; Johnson, W. Neil; Poutanen, Juri; Magdziarz, Pawel; Gierlinski, Marek

1997-01-01

Observations and theoretical models of X-ray/gamma ray spectra of radio quiet Seyfert galaxies and Galactic black hole candidates are reviewed. The spectra from these objects share the following characteristics: an underlying power law with a high energy cutoff above 200 keV; a Compton reflection component with a Fe K alpha line, and a low energy absorption by intervening cold matter. The X-ray energy spectral index, alpha, is typically in the range between 0.8 and 1 in Seyfert spectra, and that of the hard state spectra of the black hole candidates Cygnus X-1 and GX 339-4 is typically between 0.6 and 0.8. The Compton reflection component corresponds with cold matter covering a solid angle of between 0.8pi and 2pi as seen from the X-ray source. The broadband spectra of both classes of sources are well fitted by Compton upscattering of soft photons in thermal plasma. The fits yield a thermal plasma temperature of 100 keV and the Thomson optical depth of 1. All the spectra presented are cut off before the electron rest energy 511 keV, indicating that electron/positron pair production is an important process.

HESS J1943+213: A candidate extreme BL Lacertae object

DOE PAGES

Abramowski, A.; Acero, F.; Aharonian, F.; ...

2011-03-30

In this paper, we report on a newly detected point-like source, HESS J1943+213. This source coincides with an unidentified hard X-ray source IGR J19443+2117, which was proposed to have radio and infrared counterparts. Here, we combine new H.E.S.S., Fermi/LAT and Nançay Radio Telescope observations with pre-existing non-simultaneous multi-wavelength observations of IGR J19443+2117 and discuss the likely source associations as well as the interpretation as an active galactic nucleus, a gamma-ray binary or a pulsar wind nebula.

LIGO Triggered Search for Coincidence with High Energy Photon Survey Missions

NASA Technical Reports Server (NTRS)

Camp, Jordan

2009-01-01

LIGO is about to begin a new, higher sensitivity science run, where gravitational detection is plausible. A possible candidate for detection is a compact binary merger, which would also be likely to emit a high energy electromagnetic signal. Coincident observation of the gw signal from a compact merger with an x-ray or gamma-ray signal would add considerable weight to the claim for gw detection. In this talk I will consider the possibility of using LIGO triggers with time and sky position to perform a coincident analysis of EM signals from the RXTE, SWIFT, and FERMI missions.

Merging strangeon stars

NASA Astrophysics Data System (ADS)

Lai, Xiao-Yu; Yu, Yun-Wei; Zhou, En-Ping; Li, Yun-Yang; Xu, Ren-Xin

2018-02-01

The state of supranuclear matter in compact stars remains puzzling, and it is argued that pulsars could be strangeon stars. What would happen if binary strangeon stars merge? This kind of merger could result in the formation of a hyper-massive strangeon star, accompanied by bursts of gravitational waves and electromagnetic radiation (and even a strangeon kilonova explained in the paper). The tidal polarizability of binary strangeon stars is different from that of binary neutron stars, because a strangeon star is self-bound on the surface by the fundamental strong force while a neutron star by the gravity, and their equations of state are different. Our calculation shows that the tidal polarizability of merging binary strangeon stars is favored by GW170817. Three kinds of kilonovae (i.e., of neutron, quark and strangeon) are discussed, and the light curve of the kilonova AT 2017 gfo following GW170817 could be explained by considering the decaying strangeon nuggets and remnant star spin-down. Additionally, the energy ejected to the fireball around the nascent remnant strangeon star, being manifested as a gamma-ray burst, is calculated. It is found that, after a prompt burst, an X-ray plateau could follow in a timescale of 102 ‑ 103 s. Certainly, the results could be tested also by further observational synergies between gravitational wave detectors (e.g., Advanced LIGO) and X-ray telescopes (e.g., the Chinese HXMT satellite and eXTP mission), and especially if the detected gravitational wave form is checked by peculiar equations of state provided by the numerical relativistical simulation.

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.

The 2017 Periastron Passage of PSR J2032+4127 in GeV Gamma rays

NASA Astrophysics Data System (ADS)

Johnson, Tyrel; Ray, Paul S.; Kerr, Matthew T.; Wood, Kent S.; Fermi Large Area Telescope Collaboration

2018-01-01

Pulsations from the 143 ms PSR J2032+4127 were discovered in 2008 using the Fermi Large Area Telescope (LAT) and subsequently detected in radio. Continued timing revealed it is in a wide and eccentric binary with the Be star MT91 213. With an orbital period of ~50 years, the periastron on 2017 November 13 is the only one we will observe in our lifetimes. By analogy with PSR B1259-63, a similar system, a GeV gamma-ray flare, from interactions of the Be star and pulsar winds, is expected near periastron. As part of a multi-wavelength campaign, we are continually monitoring the GeV emission from this system with the LAT. We will describe analysis and present preliminary results. Portions of this research performed at the US Naval Research Laboratory are sponsored by NASA DPR S-15633-Y and Fermi Guest Investigator Grant #16-Fermi10-0006.

Magnetized hypermassive neutron-star collapse: a central engine for short gamma-ray bursts.

PubMed

Shibata, Masaru; Duez, Matthew D; Liu, Yuk Tung; Shapiro, Stuart L; Stephens, Branson C

2006-01-27

A hypermassive neutron star (HMNS) is a possible transient formed after the merger of a neutron-star binary. In the latest axisymmetric magnetohydrodynamic simulations in full general relativity, we find that a magnetized HMNS undergoes "delayed" collapse to a rotating black hole (BH) as a result of angular momentum transport via magnetic braking and the magnetorotational instability. The outcome is a BH surrounded by a massive, hot torus with a collimated magnetic field. The torus accretes onto the BH at a quasisteady accretion rate [FORMULA: SEE TEXT]; the lifetime of the torus is approximately 10 ms. The torus has a temperature [FORMULA: SEE TEXT], leading to copious ([FORMULA: SEE TEXT]) thermal radiation that could trigger a fireball. Therefore, the collapse of a HMNS is a promising scenario for generating short-duration gamma-ray bursts and an accompanying burst of gravitational waves and neutrinos.

A Search for Early High-Energy Afterglows in BATSE Gamma-Ray Bursts

NASA Technical Reports Server (NTRS)

Giblin, Timothy W.

2003-01-01

The scope of this project was to perform a detailed search for the early high-energy afterglow component of gamma-ray bursts (GRBs) in the BATSE GRB data archive. GRBs are believed to be the product of shock waves generated in a relativistic outflow from the demise of extremely massive stars and/or binary neutron star mergers. The outflow undeniably encounters the ambient medium of the progenitor object and another shock wave is set up. A forward shock propagates into the medium and a reverse shock propagates through the ejecta. This "external" shock dissipates the kinetic energy of the ejecta in the form of radiation via synchrotron losses and slows the outflow eventually to a non-relativistic state. Radiation from the forward external shock is therefore expected to be long-lived, lasting days, weeks, and even months. This radiation is referred to as the 'afterglow'.

Supernovae and gamma-ray bursts: The moment of the formation of a black hole and a newly born neutron star

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

Ruffini, Remo, E-mail: ruffini@icra.it; ICRANet, Piazzale della Repubblica 10, I-65122 Pescara; Université de Nice Sophie Antipolis, Nice, CEDEX 2 Grand Château Parc Valros

2014-01-14

We review recent progress in our understanding of the nature of gamma ray bursts (GRBs) and in particular, in the relationship between the short GRBs and the long GRBs. The coincidental occurence of a GRB with a Supernova (SN) is explained within the Induced Gravitational Collapse (IGC) paradigm, following the sequence: 1) an initial binary system consists in a compact Carbon-Oxygen (CO) core and a NS; 2) the CO core explodes giving origin to a SN and part of the SN ejecta accretes onto the NS which reaches its critical mass and collapses to a BH giving rise to amore » long GRB; 3) a new NS is generated by the SN as a remnant. The observational consequences of this scenario are outlined. The first example of a short GRB is given.« less

A magnetically driven origin for the low luminosity GRB 170817A associated with GW170817

NASA Astrophysics Data System (ADS)

Tong, Hao; Yu, Cong; Huang, Lei

2018-06-01

The gamma-ray burst GR170817A associated with GW170817 is subluminous and subenergetic compared with other typical short gamma-ray bursts. It may be due to a relativistic jet viewed off-axis, or a structured jet or cocoon emission. Giant flares from magnetars may possibly be ruled out. However, the luminosity and energetics of GRB 170817A are coincident with those of magnetar giant flares. After the coalescence of a binary neutron star, a hypermassive neutron star may be formed. The hypermassive neutron star may have a magnetar-strength magnetic field. During the collapse of this hypermassive neutron star, magnetic field energy will also be released. This giant-flare-like event may explain the luminosity and energetics of GRB 170817A. Bursts with similar luminosity and energetics are expected in future neutron star-neutron star or neutron star-black hole mergers.

VERITAS Observations of the Nova in V407 Cygni

NASA Technical Reports Server (NTRS)

Aliu, E.; Archambault, S.; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Bouvier, A.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.;

When Charged Black Holes Merge

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2016-08-01

Most theoretical models assume that black holes arent charged. But a new study shows that mergers of charged black holes could explain a variety of astrophysical phenomena, from fast radio bursts to gamma-ray bursts.No HairThe black hole no hair theorem states that all black holes can be described by just three things: their mass, their spin, and their charge. Masses and spins have been observed and measured, but weve never measured the charge of a black hole and its widely believed that real black holes dont actually have any charge.That said, weve also never shown that black holes dont have charge, or set any upper limits on the charge that they might have. So lets suppose, for a moment, that its possible for a black hole to be charged. How might that affect what we know about the merger of two black holes? A recent theoretical study by Bing Zhang (University of Nevada, Las Vegas) examines this question.Intensity profile of a fast radio burst, a sudden burst of radio emission that lasts only a few milliseconds. [Swinburne Astronomy Productions]Driving TransientsZhangs work envisions a pair of black holes in a binary system. He argues that if just one of the black holes carries charge possibly retained by a rotating magnetosphere then it may be possible for the system to produce an electromagnetic signal that could accompany gravitational waves, such as a fast radio burst or a gamma-ray burst!In Zhangs model, the inspiral of the two black holes generates a global magnetic dipole thats perpendicular to the plane of the binarys orbit. The magnetic flux increases rapidly as the separation between the black holes decreases, generating an increasingly powerful magnetic wind. This wind, in turn, can give rise to a fast radio burst or a gamma-ray burst, depending on the value of the black holes charge.Artists illustration of a short gamma-ray burst, thought to be caused by the merger of two compact objects. [ESO/A. Roquette]Zhang calculates lower limits on the charge necessary to produce each phenomenon. For a 10-solar-mass black hole, he finds that the merger can generate a fast radio burst if the black holes charge is more than ~1012 Coulombs (roughly one billion times the charge that travels through a AA battery from full to empty). If its charge is more than ~1016 Coulombs, it can generate a gamma-ray burst.Limits on ChargeZhangs calculations are not just useful in the hypothetical scenario where black holes are charged. They could, in fact, be a way of testing whether black holes are charged.As we accumulate future gravitational-wave observations (and with two observations by LIGO already announced, it seems likely that there will be many more), we will grow a larger sample of follow-up observations in radio through gamma-ray wavelengths. Our detections or our lack of detections of fast radio bursts or gamma-ray bursts associated with these black-hole mergers will allow us to set some of the first real limits on the charge of black holes.CitationBing Zhang 2016 ApJ 827 L31. doi:10.3847/2041-8205/827/2/L31

Diagnostic Accuracy of Full-Body Linear X-Ray Scanning in Multiple Trauma Patients in Comparison to Computed Tomography.

PubMed

Jöres, A P W; Heverhagen, J T; Bonél, H; Exadaktylos, A; Klink, T

2016-02-01

The purpose of this study was to evaluate the diagnostic accuracy of full-body linear X-ray scanning (LS) in multiple trauma patients in comparison to 128-multislice computed tomography (MSCT). 106 multiple trauma patients (female: 33; male: 73) were retrospectively included in this study. All patients underwent LS of the whole body, including extremities, and MSCT covering the neck, thorax, abdomen, and pelvis. The diagnostic accuracy of LS for the detection of fractures of the truncal skeleton and pneumothoraces was evaluated in comparison to MSCT by two observers in consensus. Extremity fractures detected by LS were documented. The overall sensitivity of LS was 49.2 %, the specificity was 93.3 %, the positive predictive value was 91 %, and the negative predictive value was 57.5 %. The overall sensitivity for vertebral fractures was 16.7 %, and the specificity was 100 %. The sensitivity was 48.7 % and the specificity 98.2 % for all other fractures. Pneumothoraces were detected in 12 patients by CT, but not by LS. 40 extremity fractures were detected by LS, of which 4 fractures were dislocated, and 2 were fully covered by MSCT. The diagnostic accuracy of LS is limited in the evaluation of acute trauma of the truncal skeleton. LS allows fast whole-body X-ray imaging, and may be valuable for detecting extremity fractures in trauma patients in addition to MSCT.  The overall sensitivity of LS for truncal skeleton injuries in multiple-trauma patients was < 50 %. The diagnostic reference standard MSCT is the preferred and reliable imaging modality. LS may be valuable for quick detection of extremity fractures. © Georg Thieme Verlag KG Stuttgart · New York.

X-Ray Emission from an Asymmetric Blast Wave and a Massive White Dwarf in the Gamma Ray Emitting Nova V407 CYG

NASA Technical Reports Server (NTRS)

Nelson, Thomas; Donato, Davide; Mukai, Koji; Sokoloski, Jennifer; Chomiuk, Laura

2012-01-01

Classical nova events in symbiotic stars, although rare, offer a unique opportunity to probe the interaction between ejecta and a dense environment in stellar explosions. In this work, we use X-ray data obtained with Swift and Suzaku during the recent classical nova outburst in V407 Cyg to explore such an interaction. We find evidence of both equilibrium and non-equilibrium ionization plasmas at the time of peak X-ray brightness, indicating a strong asymmetry in the density of the emitting region. Comparing a simple model to the data, we find that the X-ray evolution is broadly consistent with nova ejecta driving a forward shock into the dense wind of the Mira companion. We detect a highly absorbed soft X-ray component in the spectrum during the first 50 days of the outburst that is consistent with supersoft emission from the nuclear burning white dwarf. The high temperature and short turn off time of this emission component, in addition to the observed breaks in the optical and UV lightcurves, indicate that the white dwarf in the binary is extremely massive. Finally, we explore the connections between the X-ray and GeV-ray evolution, and propose that the gamma ray turn-off is due to the stalling of the forward shock as the ejecta reach the red giant surface.

Radio Detection of LAT PSRs J1741-2054 and J2032+4127: No Longer Just Gamma-Ray Pulsars

DOE PAGES

Camilo, F.; Ray, P. S.; Ransom, S. M.; ...

2009-10-07

We present that sixteen pulsars have been discovered so far in blind searches of photons collected with the Large Area Telescope on the Fermi Gamma-ray Space Telescope. We here report the discovery of radio pulsations from two of them. PSR J1741-2054, with period P = 413 ms, was detected in archival Parkes telescope data and subsequently has been detected at the Green Bank Telescope (GBT). Its received flux varies greatly due to interstellar scintillation and it has a very small dispersion measure of DM = 4.7 pc cm –3, implying a distance of ≈0.4 kpc and possibly the smallest luminosity of any known radio pulsar. At this distance, for isotropic emission, its gamma-ray luminosity above 0.1 GeV corresponds to 28% of the spin-down luminosity ofmore » $$\\dot{E} = 9.4\\times 10^{33}$$ erg s–1. The gamma-ray profile occupies 1/3 of pulse phase and has three closely spaced peaks with the first peak lagging the radio pulse by δ = 0.29 P. We have also identified a soft Swift source that is the likely X-ray counterpart. In many respects PSR J1741-2054 resembles the Geminga pulsar. The second source, PSR J2032+4127, was detected at the GBT. It has P = 143 ms, and its DM = 115 pc cm –3 suggests a distance of ≈3.6 kpc, but we consider it likely that it is located within the Cyg OB2 stellar association at half that distance. The radio emission is nearly 100% linearly polarized, and the main radio peak precedes by δ = 0.15 P the first of two narrow gamma-ray peaks that are separated by Δ = 0.50 P. The second peak has a harder spectrum than the first one, following a trend observed in young gamma-ray pulsars. Faint, diffuse X-ray emission in a Chandra image is possibly its pulsar wind nebula. Finally, the wind of PSR J2032+4127 is responsible for the formerly unidentified HEGRA source TeV J2032+4130. PSR J2032+4127 is coincident in projection with MT91 213, a Be star in Cyg OB2, although apparently not a binary companion of it.« less

Implications for the Origin of GRB 051103 from LIGO Observations

NASA Technical Reports Server (NTRS)

Bizouard, M. A.; Dietz, A.; Guidi, G. M.; Was, M.; Camp, J. B.; Cannizzo, J.; Stroeer, A. S.; Blackburn, L.

2012-01-01

We present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, a short-duration hard-spectrum gamma-ray burst whose electromagnetically determined sky position is coincident with the spiral galaxy M81, which is 3.6Mpc from Earth. Possible progenitors for short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce a characteristic GW signal that should be detectable at the distance of M81, while GW emission from an SGR is not expected to be detectable at that distance. We found no evidence of a GW signal associated with GRB 051103. Assuming weakly beamed gamma-ray emission with a jet semi-angle of 30. we exclude a binary neutron star merger in M81 as the progenitor with a confidence of 98%. Neutron star-black hole mergers are excluded with > 99% confidence. If the event occurred in M81 our findings support the hypothesis that GRB 051103 was due to an SGR giant flare, making it the most distant extragalactic magnetar observed to date.

Fermi's Motion Produces a Study in Spirograph

NASA Image and Video Library

2017-12-08

The LAT's sensitivity to gamma rays is greatest in the center of its wide field of view and decreases toward the edge. LAT scientists regard the effective limit of the instrument's field of view to be 78.5 degrees (red circle) from its center. View a video of this here: bit.ly/Y2K4LN. Credit: NASA/DOE/Fermi LAT Collaboration ----- NASA's Fermi Gamma-ray Space Telescope orbits our planet every 95 minutes, building up increasingly deeper views of the universe with every circuit. Its wide-eyed Large Area Telescope (LAT) sweeps across the entire sky every three hours, capturing the highest-energy form of light -- gamma rays -- from sources across the universe. These range from supermassive black holes billions of light-years away to intriguing objects in our own galaxy, such as X-ray binaries, supernova remnants and pulsars. Now a Fermi scientist has transformed LAT data of a famous pulsar into a mesmerizing movie that visually encapsulates the spacecraft's complex motion. Click here to continue reading: 1.usa.gov/WhYwCU 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

Long-term variability in bright hard X-ray sources: 5+ years of BATSE data

NASA Technical Reports Server (NTRS)

Robinson, C. R.; Harmon, B. A.; McCollough, M. L.; Paciesas, W. S.; Sahi, M.; Scott, D. M.; Wilson, C. A.; Zhang, S. N.; Deal, K. J.

1997-01-01

The operation of the Compton Gamma Ray Observatory (CGRO)/burst and transient source experiment (BATSE) continues to provide data for inclusion into a data base for the analysis of long term variability in bright, hard X-ray sources. The all-sky capability of BATSE provides up to 30 flux measurements/day for each source. The long baseline and the various rising and setting occultation flux measurements allow searches for periodic and quasi-periodic signals with periods of between several hours to hundreds of days to be conducted. The preliminary results from an analysis of the hard X-ray variability in 24 of the brightest BATSE sources are presented. Power density spectra are computed for each source and profiles are presented of the hard X-ray orbital modulations in some X-ray binaries, together with amplitude modulations and variations in outburst durations and intensities in recurrent X-ray transients.

Black Hole Mass Determination In the X-Ray Binary 4U 1630-47: Scaling of Spectral and Variability Characteristics

NASA Technical Reports Server (NTRS)

Seifina, Elena; Titarchuk, Lev; Shaposhnikov, Nikolai

2014-01-01

We present the results of a comprehensive investigation on the evolution of spectral and timing properties of the Galactic black hole candidate 4U 1630-47 during its spectral transitions. In particular, we show how a scaling of the correlation of the photon index of the Comptonized spectral component gamma with low-frequency quasi-periodic oscillations (QPOs), ?(sub L), and mass accretion rate, M, can be applied to the black hole mass and the inclination angle estimates.We analyze the transition episodes observed with the Rossi X-Ray Timing Explorer and BeppoSAX satellites.We find that the broadband X-ray energy spectra of 4U 1630-47 during all spectral states can be modeled by a combination of a thermal component, a Comptonized component, and a red-skewed iron-line component. We also establish that gamma monotonically increases during transition from the low-hard state to the high-soft state and then saturates for high mass accretion rates. The index saturation levels vary for different transition episodes. Correlations of gamma versus ?(sub L) also show saturation at gamma (is) approximately 3. Gamma -M and gamma -?(sub L) correlations with their index saturation revealed in 4U 1630-47 are similar to those established in a number of other black hole candidates and can be considered as an observational evidence for the presence of a black hole in these sources. The scaling technique, which relies on XTE J1550-564, GRO 1655-40, and H1743-322 as reference sources, allows us to evaluate a black hole mass in 4U 1630-47 yielding M(sub BH) (is) approximately 10 +/- 0.1 solar masses and to constrain the inclination angle of i (is) approximately less than 70 deg.

Measurements of Cyclotron Features and Pulse Periods in the High-Mass X-Ray Binaries 4U 1538-522 and 4U 1907+09 with the International Gamma-Ray Astrophysics Laboratory

NASA Technical Reports Server (NTRS)

Hemphill, Paul B.; Rothschild, Richard E.; Caballero, Isabel; Pottschmidt, Katja; Kuhnel, Matthias; Furst, Felix; Wilms, Jorn

2013-01-01

We present a spectral and timing analysis of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of two high-mass X-ray binaries, 4U 1538-522 and 4U 1907+09. Our timing measurements for 4U 1538-522 find the pulse period to have exhibited a spin-up trend until approximately 2009, after which there is evidence for a torque reversal, with the source beginning to spin down to the most recently measured period of 525.407 plus or minus 0.001 seconds. The most recent INTEGRAL observations of 4U 1907+09 are not found to yield statistically significant pulse periods due to the significantly lower flux from the source compared with 4U 1538-522. A spectral model consisting of a power-law continuum with an exponential cutoff and modified by two cyclotron resonance scattering features is found to fit both sources well, with the cyclotron scattering features detected at approximately 22 and approximately 49 kiloelectronvolts for 4U 1538-522 and at approximately 18 and approximately 36 kiloelectronvolts for 4U 1907+09. The spectral parameters of 4U 1538-522 are generally not found to vary significantly with flux and there is little to no variation across the torque reversal. Examining our results in conjunction with previous work, we find no evidence for a correlation between cyclotron line energy and luminosity for 4U 1538-522. 4U 1907+09 shows evidence for a positive correlation between cyclotron line energy and luminosity, which would make it the fourth, and lowest luminosity, cyclotron line source to exhibit this relationship.

MEASUREMENTS OF CYCLOTRON FEATURES AND PULSE PERIODS IN THE HIGH-MASS X-RAY BINARIES 4U 1538–522 AND 4U 1907+09 WITH THE INTERNATIONAL GAMMA-RAY ASTROPHYSICS LABORATORY

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

Hemphill, Paul B.; Rothschild, Richard E.; Caballero, Isabel

We present a spectral and timing analysis of International Gamma-Ray Astrophysics Laboratory (INTEGRAL) observations of two high-mass X-ray binaries, 4U 1538–522 and 4U 1907+09. Our timing measurements for 4U 1538–522 find the pulse period to have exhibited a spin-up trend until approximately 2009, after which there is evidence for a torque reversal, with the source beginning to spin down to the most recently measured period of 525.407 ± 0.001 s. The most recent INTEGRAL observations of 4U 1907+09 are not found to yield statistically significant pulse periods due to the significantly lower flux from the source compared with 4U 1538–522.more » A spectral model consisting of a power-law continuum with an exponential cutoff and modified by two cyclotron resonance scattering features is found to fit both sources well, with the cyclotron scattering features detected at ∼22 and ∼49 keV for 4U 1538–522 and at ∼18 and ∼36 keV for 4U 1907+09. The spectral parameters of 4U 1538–522 are generally not found to vary significantly with flux and there is little to no variation across the torque reversal. Examining our results in conjunction with previous work, we find no evidence for a correlation between cyclotron line energy and luminosity for 4U 1538–522. 4U 1907+09 shows evidence for a positive correlation between cyclotron line energy and luminosity, which would make it the fourth, and lowest luminosity, cyclotron line source to exhibit this relationship.« less

A Light-curve Analysis of Gamma-Ray Nova V959 Mon: Distance and White Dwarf Mass

NASA Astrophysics Data System (ADS)

Hachisu, Izumi; Kato, Mariko

2018-05-01

V959 Mon is a nova detected in gamma-rays. It was discovered optically about 50 days after the gamma-ray detection owing to its proximity to the Sun. The nova’s speed class is unknown because of the lack of the earlier half of its optical light curve and a short supersoft X-ray phase due to eclipse by the disk rim. Using the universal decline law and time-stretching method, we analyzed the data on V959 Mon and obtained nova parameters. We estimated the distance modulus in the V band to be (m ‑ M) V = 13.15 ± 0.3 for the reddening of E(B ‑ V) = 0.38 ± 0.01 by directly comparing it with novae of a similar type—LV Vul, V1668 Cyg, IV Cep, and V1065 Cen. The distance to V959 Mon is 2.5 ± 0.5 kpc. If we assume that the early phase of the light curve of V959 Mon is the same as that of time-stretched light curves of LV Vul, our model fitting of the light curve suggests that the white dwarf (WD) mass is 0.9–1.15 M ⊙, which is consistent with a neon nova identification. At the time of gamma-ray detection the photosphere of the nova envelope extends to 5–8 R ⊙ (about two or three times the binary separation) and the wind mass-loss rate is (3{--}4)× {10}-5 {M}ȯ yr‑1. The period of hard X-ray emission is consistent with the time of appearance of the companion star from the nova envelope. The short supersoft X-ray turnoff time is consistent with the epoch when the WD photosphere shrank to behind the rising disk rim, which occurred 500 days before nuclear burning turned off.

Obituary: Paul Barr, 1955-2005

NASA Astrophysics Data System (ADS)

Parmar, Arvind

2007-12-01

Paul Barr, an extragalactic astronomer and spacecraft mission planner, died on 19 October 2005 at his home in Noordwijk, the Netherlands, at the age of 50. Although his scientific interests ranged from AGN to X-ray binaries, he will perhaps best be remembered for his mission planning skills on EXOSAT, ISO, and Integral. Many hundreds of observers have benefited from his ability to juggle seemingly impossible observing constraints and arrive at the optimum observing program. A rare talent. Barr was born in Sunderland, England, on 28 July 1995. After attending Saint Aidans Grammar School, where his father was the headmaster, he obtained his Bachelors Degree in astronomy from the University of London (June 1976) before moving to the Mullard Space Science Laboratory. There he obtained his Doctorate in X-ray astronomy in February 1980, using data from the Ariel V and Copernicus satellites. After a Post-Doctoral position at London University, where he did research into ultra-violet emission from AGN and X-ray binaries using IUE, Paul joined ESA in 1983. He worked on a wide range of missions including EXOSAT, ISO, and Integral. These observatories spanned the wavelength range from the Infra-red to the gamma-ray, giving insight into Paul's flexibility and ability to contribute in many areas. On ISO, Paul oversaw the scientific development and use of the very successful observation scheduling system — this topic became his specialty. As ISO operations became routine, he took up the challenge of space-borne gamma-ray astronomy and moved in 1997 to Integral where he worked in the Science Operation Centre (ISOC), at ESTEC in the Netherlands, as senior mission planner. He worked with the gamma-ray imager (IBIS) instrument team to ensure that operations of their instrument were properly supported by ESA and supported preparations of announcements of opportunity. In early 2005 the ISOC moved to Europe's Space Astronomy Centre (ESAC) just outside Madrid, Spain. Paul, however, decided to stay put physically, but move on scientifically, and transferred to the Ulysses mission where he joined the software development team. We miss a uniquely flexible scientist in these days of increasing specialization and a colleague with an infectious enthusiasm for all things to do with Sunderland, especially the football club.

X-ray observations of Galactic H.E.S.S. sources: an update

NASA Astrophysics Data System (ADS)

Puehlhofer, G.; Eger, P.; Sasaki, M.; Gottschall, D.; Capasso, M.; H. E. S. S. Collaboration

2016-06-01

X-ray diagnostics of TeV sources continues to be an important tool to identify the nature of newly detected sources as well as to pinpoint the physics processes that are at work in these highly energetic objects. The contribution aims at giving a review of recent studies that we have performed on TeV sources with H.E.S.S. and XMM-Newton and also other X-ray facilities. Here, we will mainly focus on Galactic objects such as gamma-ray binaries, pulsar wind nebulae, and supernova remnants (SNRs). Particular emphasis will be given to SNR studies, including recently identified SNRs such as HESS J1731-347 and HESS J1534-571 as well as a revisit of RX J1713.7-3946.

The bright unidentified γ-ray source 1FGL J1227.9–4852: Can it be associated with a low-mass X-ray binary? [The bright unidentified γ-ray source 1FGL J1227.9–4852: Can it be associated with an LMXB?

DOE PAGES

Hill, A. B.; Szostek, A.; Corbel, S.; ...

2011-07-08

We present an analysis of high energy (HE; 0.1–300 GeV) γ-ray observations of 1FGL J1227.9–4852 with the Fermi Gamma-ray Space Telescope, follow-up radio observations with the Australia Telescope Compact Array, Giant Metrewave Radio Telescope and Parkes radio telescopes of the same field and follow-up optical observations with the ESO VLT. We also examine archival XMM– Newton and INTEGRAL X-ray observations of the region around this source. The γ-ray spectrum of 1FGL J1227.9–4852 is best fitted with an exponentially cut-off power law, reminiscent of the population of pulsars observed by Fermi. A previously unknown, compact radio source within the 99.7 permore » cent error circle of 1FGL J1227.9–4852 is discovered and has a morphology consistent either with an AGN core/jet structure or with two roughly symmetric lobes of a distant radio galaxy. A single bright X-ray source XSS J12270–4859, a low-mass X-ray binary, also lies within the 1FGL J1227.9–4852 error circle and we report the first detection of radio emission from this source. The potential association of 1FGL J1227.9–4852 with each of these counterparts is discussed. Based upon the available data we find the association of the γ-ray source to the compact double radio source unlikely and suggest that XSS J12270–4859 is a more likely counterpart to the new HE source. As a result, we propose that XSS J12270–4859 may be a millisecond binary pulsar and draw comparisons with PSR J1023+0038.« less

Pathogenesis and therapeutic approaches for improved topical treatment in localized scleroderma and systemic sclerosis.

PubMed

Badea, I; Taylor, M; Rosenberg, A; Foldvari, M

2009-03-01

SSc is a chronic progressive disorder of unknown aetiology characterized by excess synthesis and deposition of collagen and other extracellular matrix components in a variety of tissues and organs. Localized scleroderma (LS) differs from SSc in that with LS only skin and occasionally subcutaneous tissues are involved. Although rarely life threatening, LS can be disfiguring and disabling and, consequently, can adversely affect quality of life. There is no known effective treatment for LS, and various options, including, as examples, corticosteroids and other immunomodulatory agents, ultraviolet radiation and vitamin D analogues, are of unproven efficacy. Clinical trials evaluating combination therapy such as corticosteroids with MTX or UVA1 exposure with psoralens have not been established as consistently effective. New immunomodulators such as tacrolimus and thalidomide are also being evaluated. A better understanding of the molecular and cellular mechanisms of LS has led to evaluation of new treatments that modulate profibrotic cytokines such as TGF-beta and IL-4, regulate assembly and deposition of extracellular matrix components, and restore Th1/Th2 immune balance by administering IL-12 or IFN-gamma. IFN-gamma acts by directly inhibiting collagen synthesis and by restoring immune balance. In this review, we evaluate current and future treatment options for LS and cutaneous involvement in SSc. Recent advances in therapy focus mainly on anti-fibrotic agents. Delivery of these drugs into the skin as the target tissue might be a key factor in developing more effective and safer therapy.

WATCHDOG: A COMPREHENSIVE ALL-SKY DATABASE OF GALACTIC BLACK HOLE X-RAY BINARIES

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

Tetarenko, B. E.; Sivakoff, G. R.; Heinke, C. O.

With the advent of more sensitive all-sky instruments, the transient universe is being probed in greater depth than ever before. Taking advantage of available resources, we have established a comprehensive database of black hole (and black hole candidate) X-ray binary (BHXB) activity between 1996 and 2015 as revealed by all-sky instruments, scanning surveys, and select narrow-field X-ray instruments on board the INTErnational Gamma-Ray Astrophysics Laboratory, Monitor of All-Sky X-ray Image, Rossi X-ray Timing Explorer, and Swift telescopes; the Whole-sky Alberta Time-resolved Comprehensive black-Hole Database Of the Galaxy or WATCHDOG. Over the past two decades, we have detected 132 transient outbursts, trackedmore » and classified behavior occurring in 47 transient and 10 persistently accreting BHs, and performed a statistical study on a number of outburst properties across the Galactic population. We find that outbursts undergone by BHXBs that do not reach the thermally dominant accretion state make up a substantial fraction (∼40%) of the Galactic transient BHXB outburst sample over the past ∼20 years. Our findings suggest that this “hard-only” behavior, observed in transient and persistently accreting BHXBs, is neither a rare nor recent phenomenon and may be indicative of an underlying physical process, relatively common among binary BHs, involving the mass-transfer rate onto the BH remaining at a low level rather than increasing as the outburst evolves. We discuss how the larger number of these “hard-only” outbursts and detected outbursts in general have significant implications for both the luminosity function and mass-transfer history of the Galactic BHXB population.« less

WATCHDOG: A Comprehensive All-sky Database of Galactic Black Hole X-ray Binaries

NASA Astrophysics Data System (ADS)

Tetarenko, B. E.; Sivakoff, G. R.; Heinke, C. O.; Gladstone, J. C.

2016-02-01

With the advent of more sensitive all-sky instruments, the transient universe is being probed in greater depth than ever before. Taking advantage of available resources, we have established a comprehensive database of black hole (and black hole candidate) X-ray binary (BHXB) activity between 1996 and 2015 as revealed by all-sky instruments, scanning surveys, and select narrow-field X-ray instruments on board the INTErnational Gamma-Ray Astrophysics Laboratory, Monitor of All-Sky X-ray Image, Rossi X-ray Timing Explorer, and Swift telescopes; the Whole-sky Alberta Time-resolved Comprehensive black-Hole Database Of the Galaxy or WATCHDOG. Over the past two decades, we have detected 132 transient outbursts, tracked and classified behavior occurring in 47 transient and 10 persistently accreting BHs, and performed a statistical study on a number of outburst properties across the Galactic population. We find that outbursts undergone by BHXBs that do not reach the thermally dominant accretion state make up a substantial fraction (∼40%) of the Galactic transient BHXB outburst sample over the past ∼20 years. Our findings suggest that this “hard-only” behavior, observed in transient and persistently accreting BHXBs, is neither a rare nor recent phenomenon and may be indicative of an underlying physical process, relatively common among binary BHs, involving the mass-transfer rate onto the BH remaining at a low level rather than increasing as the outburst evolves. We discuss how the larger number of these “hard-only” outbursts and detected outbursts in general have significant implications for both the luminosity function and mass-transfer history of the Galactic BHXB population.

Comparing the birth rate of stellar black holes in binary black hole mergers and long gamma-ray bursts

NASA Astrophysics Data System (ADS)

Atteia, J.-L.; Dezalay, J.-P.; Godet, O.; Klotz, A.; Turpin, D.; Bernardini, M. G.

2018-02-01

Context. Gravitational wave interferometers have proven the existence of a new class of binary black hole (BBH) weighing tens of solar masses, and have provided the first reliable measurement of the rate of coalescing black holes (BHs) in the local Universe. Furthermore, long gamma-ray bursts (GRBs) detected with gamma-ray satellites are believed to be associated with the birth of stellar-mass BHs, providing a measure of the rate of these events across the history of the Universe, thanks to the measure of their cosmological redshift. These two types of sources, which are subject to different detection biases and involve BHs born in different environments with potentially different characteristics, provide complementary information on the birth rate of stellar BHs. Aim. We compare the birth rates of BHs found in BBH mergers and in long GRBs. Methods: We construct a simple model that makes reasonable assumptions on the history of GRB formation, and takes into account some major uncertainties, like the beaming angle of GRBs or the delay between the formation of BBHs and their coalescence. We use this model to evaluate the ratio of the number of stellar mass BHs formed in BBH mergers to those formed in GRBs. Results: We find that in our reference model the birth rate of stellar BHs in BBH mergers represents a significant fraction of the rate of long GRBs and that comparable birth rates are favored by models with moderate beaming angles. These numbers, however, do not consider subluminous GRBs, which may represent another population of sources associated with the birth of stellar mass BHs. We briefly discuss this result in view of our understanding of the progenitors of GRBs and BBH mergers, and we emphasize that this ratio, which will be better constrained in the coming years, can be directly compared with the prediction of stellar evolution models if a single model is used to produce GRBs and BBH mergers with the same assumptions.

Poisson denoising on the sphere: application to the Fermi gamma ray space telescope

NASA Astrophysics Data System (ADS)

Schmitt, J.; Starck, J. L.; Casandjian, J. M.; Fadili, J.; Grenier, I.

2010-07-01

The Large Area Telescope (LAT), the main instrument of the Fermi gamma-ray Space telescope, detects high energy gamma rays with energies from 20 MeV to more than 300 GeV. The two main scientific objectives, the study of the Milky Way diffuse background and the detection of point sources, are complicated by the lack of photons. That is why we need a powerful Poisson noise removal method on the sphere which is efficient on low count Poisson data. This paper presents a new multiscale decomposition on the sphere for data with Poisson noise, called multi-scale variance stabilizing transform on the sphere (MS-VSTS). This method is based on a variance stabilizing transform (VST), a transform which aims to stabilize a Poisson data set such that each stabilized sample has a quasi constant variance. In addition, for the VST used in the method, the transformed data are asymptotically Gaussian. MS-VSTS consists of decomposing the data into a sparse multi-scale dictionary like wavelets or curvelets, and then applying a VST on the coefficients in order to get almost Gaussian stabilized coefficients. In this work, we use the isotropic undecimated wavelet transform (IUWT) and the curvelet transform as spherical multi-scale transforms. Then, binary hypothesis testing is carried out to detect significant coefficients, and the denoised image is reconstructed with an iterative algorithm based on hybrid steepest descent (HSD). To detect point sources, we have to extract the Galactic diffuse background: an extension of the method to background separation is then proposed. In contrary, to study the Milky Way diffuse background, we remove point sources with a binary mask. The gaps have to be interpolated: an extension to inpainting is then proposed. The method, applied on simulated Fermi LAT data, proves to be adaptive, fast and easy to implement.

Searching for gamma-ray counterparts to gravitational waves from merging binary neutron stars with the Cherenkov Telescope Array

NASA Astrophysics Data System (ADS)

Patricelli, B.; Stamerra, A.; Razzano, M.; Pian, E.; Cella, G.

2018-05-01

The merger of binary neutron star (BNS) systems are predicted to be progenitors of short gamma-ray bursts (GRBs); the definitive probe of this association came with the recent detection of gravitational waves (GWs) from a BNS merger by Advanced LIGO and Advanced Virgo (GW170817), in coincidence with the short GRB 170817A observed by Fermi-GBM and INTEGRAL. Short GRBs are also expected to emit very-high energy (VHE, > 10S0 GeV) photons and VHE electromagnetic (EM) upper limits have been set with observations performed by ground-based gamma-ray detectors and during the intense EM follow-up campaign associated with GW170817/GRB 170817A. In the next years, the searches for VHE EM counterparts will become more effective thanks to the Cherenkov Telescope Array (CTA): this instrument will be fundamental for the EM follow-up of transient GW events at VHE, owing to its unprecedented sensitivity, rapid response (few tens of seconds) and capability to monitor large sky areas via survey-mode operation. We present a comprehensive study on the prospects for joint GW and VHE EM observations of merging BNSs with Advanced LIGO, Advanced Virgo and CTA, based on detailed simulations of the multi-messenger emission and detection. We propose a new observational strategy optimized on the prior assumptions about the EM emission. The method can be further generalized to include other electromagnetic emission models. According to this study CTA will cover most of the region of the GW skymap for the intermediate and most energetic on-axis GRBs associated to the GW event. We estimate the expected joint GW and VHE EM detection rates and we found this rate goes from 0.08 up to 0.5 events per year for the most energetic EM sources.

Compton echoes from nearby gamma-ray bursts

NASA Astrophysics Data System (ADS)

Beniamini, Paz; Giannios, Dimitrios; Younes, George; van der Horst, Alexander J.; Kouveliotou, Chryssa

2018-06-01

The recent discovery of gravitational waves from GW170817, associated with a short gamma-ray burst (GRB) at a distance of 40 Mpc, has demonstrated that short GRBs can occur locally and at a reasonable rate. Furthermore, gravitational waves enable us to detect close-by GRBs, even when we are observing at latitudes far from the jet's axis. We consider here Compton echoes, the scattered light from the prompt and afterglow emission. Compton echoes, an as yet undetected counterpart of GRBs, peak in X-rays and maintain a roughly constant flux for hundreds to thousands of years after the burst. Though too faint to be detected in typical cosmological GRBs, a fraction of close-by bursts with a sufficiently large energy output in X-rays, and for which the surrounding medium is sufficiently dense, may indeed be observed in this way. The detection of a Compton echo could provide unique insight into the burst properties and the environment's density structure. In particular, it could potentially determine whether or not there was a successful jet that broke through the compact binary merger ejecta. We discuss here the properties and expectations from Compton echoes and suggest methods for detectability.

High-energy astrophysics and the search for sources of gravitational waves

NASA Astrophysics Data System (ADS)

O'Brien, P. T.; Evans, P.

2018-05-01

The dawn of the gravitational-wave (GW) era has sparked a greatly renewed interest into possible links between sources of high-energy radiation and GWs. The most luminous high-energy sources-gamma-ray bursts (GRBs)-have long been considered as very likely sources of GWs, particularly from short-duration GRBs, which are thought to originate from the merger of two compact objects such as binary neutron stars and a neutron star-black hole binary. In this paper, we discuss: (i) the high-energy emission from short-duration GRBs; (ii) what other sources of high-energy radiation may be observed from binary mergers; and (iii) how searches for high-energy electromagnetic counterparts to GW events are performed with current space facilities. While current high-energy facilities, such as Swift and Fermi, play a crucial role in the search for electromagnetic counterparts, new space missions will greatly enhance our capabilities for joint observations. We discuss why such facilities, which incorporate new technology that enables very wide-field X-ray imaging, are required if we are to truly exploit the multi-messenger era. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.

High-energy astrophysics and the search for sources of gravitational waves.

PubMed

O'Brien, P T; Evans, P

2018-05-28

The dawn of the gravitational-wave (GW) era has sparked a greatly renewed interest into possible links between sources of high-energy radiation and GWs. The most luminous high-energy sources-gamma-ray bursts (GRBs)-have long been considered as very likely sources of GWs, particularly from short-duration GRBs, which are thought to originate from the merger of two compact objects such as binary neutron stars and a neutron star-black hole binary. In this paper, we discuss: (i) the high-energy emission from short-duration GRBs; (ii) what other sources of high-energy radiation may be observed from binary mergers; and (iii) how searches for high-energy electromagnetic counterparts to GW events are performed with current space facilities. While current high-energy facilities, such as Swift and Fermi, play a crucial role in the search for electromagnetic counterparts, new space missions will greatly enhance our capabilities for joint observations. We discuss why such facilities, which incorporate new technology that enables very wide-field X-ray imaging, are required if we are to truly exploit the multi-messenger era.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).

Fermi's Motion Produces a Study in Spirograph

NASA Image and Video Library

2013-02-27

Final still from Fermi video [bit.ly/Y2K4LN]. Credit: NASA/DOE/Fermi LAT Collaboration ----- NASA's Fermi Gamma-ray Space Telescope orbits our planet every 95 minutes, building up increasingly deeper views of the universe with every circuit. Its wide-eyed Large Area Telescope (LAT) sweeps across the entire sky every three hours, capturing the highest-energy form of light -- gamma rays -- from sources across the universe. These range from supermassive black holes billions of light-years away to intriguing objects in our own galaxy, such as X-ray binaries, supernova remnants and pulsars. Now a Fermi scientist has transformed LAT data of a famous pulsar into a mesmerizing movie that visually encapsulates the spacecraft's complex motion. Click here to continue reading: 1.usa.gov/WhYwCU 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

Gamma Ray Burst Discoveries with the Swift Mission

NASA Technical Reports Server (NTRS)

Gehrels, Neil

2008-01-01

Gamma-ray bursts (GRBs) are among the most fascinating occurrences in the universe. They are powerful explosions, visible to high redshift, and thought to be the signature of black hole formation. The Swift Observatory has been detecting 100 bursts per year for 3 years and has greatly stimulated the field with new findings. Observations are made of the X-ray and optical afterglow from - 1 minute after the burst, continuing for days. Evidence is building that the long and short duration subcategories of GRBs have very different origins: massive star core collapse to a black hole for long bursts and binary neutron star coalescence to a black hole for short bursts. The similarity to Type I1 and Ia supernovae originating from young and old stellar progenitors is striking. Bursts are providing a new tool to study the high redshift universe. Swift has detected several events at z>5 and one at z=6.3 giving metallicity measurements and other data on galaxies at previously inaccessible distances. The talk will present the latest results from Swift in GRB astronomy.

Gamma Ray Burst Discoveries with the Swift Mission

NASA Technical Reports Server (NTRS)

Gehrels, Neil

2008-01-01

Gamma-ray bursts (GRBs) are among the most fascinating occurrences in the universe. They are powerful explosions, visible to high redshift, and thought to be the signature of black hole formation. The Swift Observatory has been detecting 100 bursts per year for 3 years and has greatly stimulated the field with new findings. Observations are made of the X-ray and optical afterglow from approximately 1 minute after the burst, continuing for days. Evidence is building that the long and short duration subcategories of GRBs have very different origins: massive star core collapse to a black hole for long bursts and binary neutron star coalescence to a black hole for short bursts. The similarity to Type II and Ia supernovae originating from young and old stellar progenitors is striking. Bursts are providing a new tool to study the high redshift universe. Swift has detected several events at z greater than 5 and one at z=6.3 giving metallicity measurements and other data on galaxies at previously inaccessible distances. The talk will present the latest results from Swift in GRB astronomy.

Gamma Ray Burst Discoveries with the Swift Mission

NASA Technical Reports Server (NTRS)

Gehrels, Neil

2009-01-01

Gamma-ray bursts (GRBs) are among the most fascinating occurrences in the universe. They are powerful explosions, visible to high redshift, and thought to be the signature of black hole formation. The Swift Observatory has been detecting 100 bursts per year for 4 years and has greatly stimulated the field with new findings. Observations are made of the X-ray and optical afterglow from approximately 1 minute after the burst, continuing for days. Evidence is building that the long and short duration subcategories of GRBs have very different origins: massive star core collapse to a black hole for long bursts and binary neutron star coalescence to a black hole for short bursts. The similarity to Type II and Ia supernovae originating from young and old stellar progenitors is striking. Bursts are providing a new tool to study the high redshift universe. Swift has detected several events at z>5 and one at z=6.7 giving metallicity measurements and other data on galaxies at previously inaccessible distances. The talk will present the latest results from Swift in GRB astronomy.

Bimodal Long-lasting Components in Short Gamma-Ray Bursts: Promising Electromagnetic Counterparts to Neutron Star Binary Mergers

NASA Astrophysics Data System (ADS)

Kisaka, Shota; Ioka, Kunihito; Sakamoto, Takanori

2017-09-01

Long-lasting emission of short gamma-ray bursts (GRBs) is crucial to reveal the physical origin of the central engine as well as to detect electromagnetic (EM) counterparts to gravitational waves (GWs) from neutron star binary mergers. We investigate 65 X-ray light curves of short GRBs, which is six times more than previous studies, by combining both Swift/BAT and XRT data. The light curves are found to consist of two distinct components at >5σ with bimodal distributions of luminosity and duration, I.e., extended (with a timescale of ≲103 s) and plateau emission (with a timescale of ≳103 s), which are likely the central engine activities, but not afterglows. The extended emission has an isotropic energy comparable to the prompt emission, while the plateau emission has ˜0.01-1 times this energy. Half (50%) of our sample has both components, while the other half is consistent with having both components. This leads us to conjecture that almost all short GRBs have both the extended and plateau emission. The long-lasting emission can be explained by the jets from black holes with fallback ejecta, and could power macronovae (or kilonovae) like GRB 130603B and GRB 160821B. Based on the observed properties, we quantify the detectability of EM counterparts to GWs, including the plateau emission scattered to the off-axis angle, with CALET/HXM, INTEGRAL/SPI-ACS, Fermi/GBM, MAXI/GSC, Swift/BAT, XRT, the future ISS-Lobster/WFI, Einstein Probe/WXT, and eROSITA.

Fermi GBM Observations of LIGO Gravitational-Wave Event Gw150914

NASA Technical Reports Server (NTRS)

Connaughton, V.; Burns, E.; Goldstein, A.; Blackburn, L.; Briggs, M. S.; Zhang, B.-B.; Camp, J.; Christensen, N.; Hui, C. M.; Jenke, P.;

Bimodal Long-lasting Components in Short Gamma-Ray Bursts: Promising Electromagnetic Counterparts to Neutron Star Binary Mergers

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

Kisaka, Shota; Sakamoto, Takanori; Ioka, Kunihito, E-mail: kisaka@phys.aoyama.ac.jp, E-mail: tsakamoto@phys.aoyama.ac.jp, E-mail: kunihito.ioka@yukawa.kyoto-u.ac.jp

Long-lasting emission of short gamma-ray bursts (GRBs) is crucial to reveal the physical origin of the central engine as well as to detect electromagnetic (EM) counterparts to gravitational waves (GWs) from neutron star binary mergers. We investigate 65 X-ray light curves of short GRBs, which is six times more than previous studies, by combining both Swift /BAT and XRT data. The light curves are found to consist of two distinct components at >5 σ with bimodal distributions of luminosity and duration, i.e., extended (with a timescale of ≲10{sup 3} s) and plateau emission (with a timescale of ≳10{sup 3} s),more » which are likely the central engine activities, but not afterglows. The extended emission has an isotropic energy comparable to the prompt emission, while the plateau emission has ∼0.01–1 times this energy. Half (50%) of our sample has both components, while the other half is consistent with having both components. This leads us to conjecture that almost all short GRBs have both the extended and plateau emission. The long-lasting emission can be explained by the jets from black holes with fallback ejecta, and could power macronovae (or kilonovae) like GRB 130603B and GRB 160821B. Based on the observed properties, we quantify the detectability of EM counterparts to GWs, including the plateau emission scattered to the off-axis angle, with CALET /HXM, INTEGRAL /SPI-ACS, Fermi /GBM, MAXI /GSC, Swift /BAT, XRT, the future ISS-Lobster /WFI, Einstein Probe /WXT, and eROSITA .« less

Supranova Events from Spun-up Neutron Stars: An Explosion in Search of an Observation

NASA Astrophysics Data System (ADS)

Vietri, Mario; Stella, Luigi

1999-12-01

We consider a formation scenario for supramassive neutron stars (SMNSs) that takes place through mass and angular momentum transfer from a close companion during a low-mass X-ray binary phase, with the ensuing suppression of the magnetic field. After the end of the mass transfer phase, SMNSs will lose, through magnetic dipole radiation, most of their angular momentum, triggering the star's collapse to a black hole. We discuss the rate of occurrence of these collapses and propose that these stars, because of the baryon-clear environment in which the implosion/explosion takes place, are the originators of gamma-ray bursts.

GRB 070610: A Curious Galactic Transient

NASA Astrophysics Data System (ADS)

Kasliwal, M. M.; Cenko, S. B.; Kulkarni, S. R.; Cameron, P. B.; Nakar, E.; Ofek, E. O.; Rau, A.; Soderberg, A. M.; Campana, S.; Bloom, J. S.; Perley, D. A.; Pollack, L. K.; Barthelmy, S.; Cummings, J.; Gehrels, N.; Krimm, H. A.; Markwardt, C. B.; Sato, G.; Chandra, P.; Frail, D.; Fox, D. B.; Price, P. A.; Berger, E.; Grebenev, S. A.; Krivonos, R. A.; Sunyaev, R. A.

2008-05-01

GRB 070610 is a typical high-energy event with a duration of 5 s. Yet within the burst localization we detect a highly unusual X-ray and optical transient, Swift J195509.6+261406. We see high-amplitude X-ray and optical variability on very short timescales even at late times. Using near-infrared imaging assisted by a laser guide star and adaptive optics, we identified the counterpart of Swift J195509.6+261406. Late-time optical and near-infrared imaging constrain the spectral type of the counterpart to be fainter than a K-dwarf, assuming it is of Galactic origin. It is possible that GRB 070610 and Swift J195509.6+261406 are unrelated sources. However, the absence of a typical X-ray afterglow from GRB 070610 in conjunction with the spatial and temporal coincidence of the two motivate us to suggest that the sources are related. The closest (imperfect) analog to Swift J195509.6+261406 is V4641 Sgr, an unusual black hole binary. We suggest that Swift J195509.6+261406 along with V4641 Sgr define a subclass of stellar black hole binaries—the fast X-ray novae. We further suggest that fast X-ray novae are associated with bursts of gamma rays. If so, GRB 070610 defines a new class of celestial gamma-ray bursts and these bursts dominate the long-duration GRB demographics.

Binary neutron star merger rate via the luminosity function of short gamma-ray bursts

NASA Astrophysics Data System (ADS)

Paul, Debdutta

2018-04-01

The luminosity function of short Gamma Ray Bursts (GRBs) is modelled by using the available catalogue data of all short GRBs (sGRBs) detected till October, 2017. The luminosities are estimated via the `pseudo-redshifts' obtained from the `Yonetoku correlation', assuming a standard delay distribution between the cosmic star formation rate and the production rate of their progenitors. While the simple powerlaw is ruled out to high confidence, the data is fit well both by exponential cutoff powerlaw and broken powerlaw models. Using the derived parameters of these models along with conservative values in the jet opening angles seen from afterglow observations, the true rate of short GRBs are derived. Assuming a short GRB is produced from each binary neutron star merger (BNSM), the rate of gravitational wave (GW) detections from these mergers are derived for the past, present and future configurations of the GW detector networks. Stringent lower limits of 1.87yr-1 for the aLIGO-VIRGO, and 3.11yr-1 for the upcoming aLIGO-VIRGO-KAGRA-LIGO/India configurations are thus derived for the BNSM rate at 68% confidence. The BNSM rates calculated from this work and that independently inferred from the observation of the only confirmed BNSM observed till date, are shown to have a mild tension; however the scenario that all BNSMs produce sGRBs cannot be ruled out.

Binary neutron star merger rate via the luminosity function of short gamma-ray bursts

NASA Astrophysics Data System (ADS)

Paul, Debdutta

2018-07-01

The luminosity function of short gamma ray bursts (GRBs) is modelled by using the available catalogue data of all short GRBs (sGRBs) detected till 2017 October. The luminosities are estimated via the `pseudo-redshifts' obtained from the `Yonetoku correlation', assuming a standard delay distribution between the cosmic star formation rate and the production rate of their progenitors. While the simple power law is ruled out to high confidence, the data is fit well both by exponential cutoff power law and broken power law models. Using the derived parameters of these models along with conservative values in the jet opening angles seen from afterglow observations, the true rate of sGRBs is derived. Assuming a sGRB is produced from each binary neutron star merger (BNSM), the rate of gravitational wave (GW) detections from these mergers are derived for the past, present, and future configurations of the GW detector networks. Stringent lower limits of 1.87 { yr^{-1}} for the aLIGO-VIRGO, and 3.11 { yr^{-1}} for the upcoming aLIGO-VIRGO-KAGRA-LIGO/India configurations are thus derived for the BNSM rate at 68 per cent confidence. The BNSM rates calculated from this work and that independently inferred from the observation of the only confirmed BNSM observed till date are shown to have a mild tension; however, the scenario that all BNSMs produce sGRBs cannot be ruled out.

ESA's Integral discovers hidden black holes

NASA Astrophysics Data System (ADS)

2003-10-01

An artist's impression of the mechanisms in an interacting binar hi-res Size hi-res: 28 kb An artist's impression of the mechanisms in an interacting binary system An artist's impression of the mechanisms in an interacting binary system. The supermassive companion star (on the right-hand side) ejects a lot of gas in the form of 'stellar wind'. The compact black hole orbits the star and, due to its strong gravitational attraction, collects a lot of the gas. Some of it is funnelled and accelerated into a hot disc. This releases a large amount of energy in all spectral bands, from gamma rays through to visible and infrared. However, the remaining gas surrounding the black hole forms a thick cloud which blocks most of the radiation. Only the very energetic gamma rays can escape and be detected by Integral. XMM-Newton spacecraft hi-res Size hi-res: 254 kb Credits: ESA. Illustration by Ducros XMM-Newton spacecraft Detecting the Universe's hot spots. These are binary systems, probably including a black hole or a neutron star, embedded in a thick cocoon of cold gas. They have remained invisible so far to all other telescopes. Integral was launched one year ago to study the most energetic phenomena in the universe. Integral detected the first of these objects, called IGRJ16318-4848, on 29 January 2003. Although astronomers did not know its distance, they were sure it was in our Galaxy. Also, after some analysis, researchers concluded that the new object could be a binary system comprising a compact object, such as a neutron star or a black hole, and a very massive companion star. When gas from the companion star is accelerated and swallowed by the more compact object, energy is released at all wavelengths, from the gamma rays through to visible and infrared light. About 300 binary systems like those are known to exist in our galactic neighbourhood and IGRJ16318-4848 could simply have been one more. But something did not fit: why this particular object had not been discovered so far? Astronomers, who have been observing the object regularly, guess that it had remained invisible because there must be a very thick shell of obscuring material surrounding it. If that was the case, only the most energetic radiation from the object could get through the shell; less-energetic radiation would be blocked. That could explain why space telescopes that are sensitive only to low-energy radiation had overlooked the object, while Integral, specialised in detecting very energetic emissions, did see it. To test their theory, astronomers turned to ESA's XMM-Newton space observatory, which observes the sky in the X-ray wavelengths. As well as being sensitive to high-energy radiation, XMM-Newton is also able to check for the presence of obscuring material. Indeed, XMM-Newton detected this object last February, as well as the existence of a dense 'cocoon' of cold gas with a diameter of similar size to that of the Earth's orbit around the Sun. This obscuring material forming the cocoon is probably 'stellar wind', namely gas ejected by the supermassive companion star. Astronomers think that this gas may be accreted by the compact black hole, forming a dense shell around it. This obscuring cloud traps most of the energy produced inside it. The main author of these results, Roland Walter of the Integral Science Data Centre, Switzerland, explained: "Only photons with the highest energies [above 10 keV] could escape from that cocoon. IGR J16318-4848 has therefore not been detected by surveys performed at lower energies, nor by previous gamma-ray missions that were much less sensitive than Integral." The question now is to find out how many of these objects lurk in the Galaxy. XMM-Newton and Integral together are the perfect tools to do the job. They have already discovered two more new sources embedded in obscuring material. Future observations are planned. Christoph Winkler, ESA Project Scientist for Integral, said: "These early examples of using two complementary ESA high-energy missions, Integral and XMM-Newton, shows the potential for future discoveries in high-energy astrophysics." Notes to Editors: The paper explaining these results will be published in November in a special issue of Astronomy and Astrophysics dedicated to Integral, on the occasion of its first anniversary. Integral The International Gamma Ray Astrophysics Laboratory (Integral) is the first space observatory that can simultaneously observe celestial objects in gamma rays, X-rays and visible light. Integral was launched on a Russian Proton rocket on 17 October 2002 into a highly elliptical orbit around Earth. Its principal targets include regions of the galaxy where chemical elements are being produced and compact objects, such as black holes. XMM-Newton XMM-Newton can detect more X-ray sources than any previous satellite and is helping to solve many cosmic mysteries of the violent Universe, from black holes to the formation of galaxies. It was launched on 10 December 1999, using an Ariane-5 rocket from French Guiana. It is expected to return data for a decade. XMM-Newton's high-tech design uses over 170 wafer-thin cylindrical mirrors spread over three telescopes. Its orbit takes it almost a third of the way to the Moon, so that astronomers can enjoy long, uninterrupted views of celestial objects.

In-beam γ -ray spectroscopy of the neutron-rich platinum isotope 200Pt toward the N =126 shell gap

NASA Astrophysics Data System (ADS)

John, P. R.; Valiente-Dobón, J. J.; Mengoni, D.; Modamio, V.; Lunardi, S.; Bazzacco, D.; Gadea, A.; Wheldon, C.; Rodríguez, T. R.; Alexander, T.; de Angelis, G.; Ashwood, N.; Barr, M.; Benzoni, G.; Birkenbach, B.; Bizzeti, P. G.; Bizzeti-Sona, A. M.; Bottoni, S.; Bowry, M.; Bracco, A.; Browne, F.; Bunce, M.; Camera, F.; Corradi, L.; Crespi, F. C. L.; Melon, B.; Farnea, E.; Fioretto, E.; Gottardo, A.; Grente, L.; Hess, H.; Kokalova, Tz.; Korten, W.; Kuşoǧlu, A.; Lenzi, S.; Leoni, S.; Ljungvall, J.; Menegazzo, R.; Michelagnoli, C.; Mijatović, T.; Montagnoli, G.; Montanari, D.; Napoli, D. R.; Podolyák, Zs.; Pollarolo, G.; Recchia, F.; Reiter, P.; Roberts, O. J.; Şahin, E.; Salsac, M.-D.; Scarlassara, F.; Sferrazza, M.; Söderström, P.-A.; Stefanini, A. M.; Szilner, S.; Ur, C. A.; Vogt, A.; Walshe, J.

2017-06-01

The neutron-rich nucleus 200Pt is investigated via in-beam γ -ray spectroscopy to study the shape evolution in the neutron-rich platinum isotopes towards the N =126 shell closure. The two-neutron transfer reaction 198Pt(82Se, 80Se)200Pt is used to populate excited states of 200Pt. The Advanced Gamma Ray Tracking Array (AGATA) demonstrator coupled with the PRISMA spectrometer detects γ rays coincident with the 80Se recoils, the binary partner of 200Pt. The binary partner method is applied to extract the γ -ray transitions and build the level scheme of 200Pt. The level at 1884 keV reported by Yates et al. [S. W. Yates, E. M. Baum, E. A. Henry, L. G. Mann, N. Roy, A. Aprahamian, R. A. Meyer, and R. Estep, Phys. Rev. C 37, 1889 (1988)] was confirmed to be at 1882.1 keV and assigned as the (61+) state. An additional γ ray was found and it presumably deexcites the (81+) state. The results are compared with state-of-the-art beyond mean-field calculations, performed for the even-even 190 -204Pt isotopes, revealing that 200Pt marks the transition from the γ -unstable behavior of lighter Pt nuclei towards a more spherical one when approaching the N =126 shell closure.

GRB 170817A as a jet counterpart to gravitational wave trigger GW 170817

NASA Astrophysics Data System (ADS)

Lamb, Gavin P.; Kobayashi, Shiho

2018-05-01

Fermi/GBM (Gamma-ray Burst Monitor) and INTEGRAL (the International Gamma-ray Astrophysics Laboratory) reported the detection of the γ-ray counterpart, GRB 170817A, to the LIGO (Light Interferometer Gravitational-wave Observatory)/Virgo gravitational wave detected binary neutron star merger, GW 170817. GRB 170817A is likely to have an internal jet or another origin such as cocoon emission, shock-breakout, or a flare from a viscous disc. In this paper we assume that the γ-ray emission is caused by energy dissipation within a relativistic jet and we model the afterglow synchrotron emission from a reverse- and forward-shock in the outflow. We show the afterglow for a low-luminosity γ-ray burst (GRB) jet with a high Lorentz-factor (Γ); a low-Γ and low-kinetic energy jet; a low-Γ, high kinetic energy jet; structured jets viewed at an inclination within the jet-half-opening angle; and an off-axis `typical' GRB jet. All jet models will produce observable afterglows on various timescales. The late-time afterglow from 10-110 days can be fit by a Gaussian structured jet viewed at a moderate inclination, however the GRB is not directly reproduced by this model. These jet afterglow models can be used for future GW detected NS merger counterparts with a jet afterglow origin.

Characterizing X-Ray and Radio Emission in the Black Hole X-Ray Binary V404 Cygni During Quiescence

NASA Technical Reports Server (NTRS)

Rana, Vikram; Loh, Alan; Corbel, Stephane; Tomsick, John A.; Chakrabarty, Deepto; Walton, Dominic J.; Barret, Didier; Boggs, Steven E.; Christensen, Finn E.; Craig, William;

GRB 080503: IMPLICATIONS OF A NAKED SHORT GAMMA-RAY BURST DOMINATED BY EXTENDED EMISSION

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

Perley, D. A.; Metzger, B. D.; Butler, N. R.

We report on observations of GRB 080503, a short gamma-ray burst (GRB) with very bright extended emission (about 30 times the gamma-ray fluence of the initial spike) in conjunction with a thorough comparison to other short Swift events. In spite of the prompt-emission brightness, however, the optical counterpart is extraordinarily faint, never exceeding 25 mag in deep observations starting at {approx}1 hr after the Burst Alert Telescope (BAT) trigger. The optical brightness peaks at {approx}1 day and then falls sharply in a manner similar to the predictions of Li and Paczynski (1998) for supernova-like emission following compact binary mergers. However,more » a shallow spectral index and similar evolution in X-rays inferred from Chandra observations are more consistent with an afterglow interpretation. The extreme faintness of this probable afterglow relative to the bright gamma-ray emission argues for a very low density medium surrounding the burst (a 'naked' GRB), consistent with the lack of a coincident host galaxy down to 28.5 mag in deep Hubble Space Telescope imaging. The late optical and X-ray peak could be explained by a slightly off-axis jet or by a refreshed shock. Our observations reinforce the notion that short GRBs generally occur outside regions of active star formation, but demonstrate that in some cases the luminosity of the extended prompt emission can greatly exceed that of the short spike, which may constrain theoretical interpretation of this class of events. This extended emission is not the onset of an afterglow, and its relative brightness is probably either a viewing-angle effect or intrinsic to the central engine itself. Because most previous BAT short bursts without observed extended emission are too faint for this signature to have been detectable even if it were present at typical level, conclusions based solely on the observed presence or absence of extended emission in the existing Swift sample are premature.« less

Millisecond Pulsars: The Gifts that Keep on Giving

NASA Astrophysics Data System (ADS)

Ransom, Scott M.

2011-01-01

There are about 2000 pulsars known, and while all of them as neutron stars are fascinating objects, the best and most exciting science comes from a very small percentage ( 1%) of exotic objects, most of which are millisecond pulsars (MSPs). These systems are notoriously hard to detect, yet their numbers have bloomed in the past 5-6 years via surveys using the world's largest radio telescopes and the Fermi Gamma-ray Space Telescope. Timing observations of these new MSPs as well as much improved monitoring of previously known MSPs are providing a wealth of science. In this talk I'll briefly cover 3 main areas in basic physics where systems like these are making an impact: strong-field tests of general relativity, the nature of matter at supra-nuclear densities, and the direct detection of gravitational waves (e.g. NANOGrav). In addition, several of the systems exhibit some very interesting astrophysics as well, including a transition from X-ray binary to MSP and a likely triple system that turned into an eccentric MSP binary.

ESA's Integral solves thirty-year old gamma-ray mystery

NASA Astrophysics Data System (ADS)

Integral solves mystery hi-res Size hi-res: 60 kb Credits: Credit: ESA, F. Lebrun (CEA-Saclay). ESA's Integral solves thirty-year old gamma-ray mystery The central regions of our galaxy, the Milky Way, as seen by Integral in gamma rays. With its superior ability to see faint details, Integral correctly reveals the individual sources that comprised the foggy, gamma-ray background seen by previous observatories. The brightest 91 objects seen in this image were classified by Integral as individual sources, while the others appear too faint to be properly characterized at this stage. During the spring and autumn of 2003, Integral observed the central regions of our Galaxy, collecting some of the perpetual glow of diffuse low-energy gamma rays that bathe the entire Galaxy. These gamma rays were first discovered in the mid-1970s by high-flying balloon-borne experiments. Astronomers refer to them as the 'soft' Galactic gamma-ray background, with energies similar to those used in medical X-ray equipment. Initially, astronomers believed that the glow was caused by interactions involving the atoms of the gas that pervades the Galaxy. Whilst this theory could explain the diffuse nature of the emission, since the gas is ubiquitous, it failed to match the observed power of the gamma rays. The gamma rays produced by the proposed mechanisms would be much weaker than those observed. The mystery has remained unanswered for decades. Now Integral's superb gamma-ray telescope IBIS, built for ESA by an international consortium led by Principal Investigator Pietro Ubertini (IAS/CNR, Rome, Italy), has seen clearly that, instead of a fog produced by the interstellar medium, most of the gamma-rays are coming from individual celestial objects. In the view of previous, less sensitive instruments, these objects appeared to merge together. In a paper published today in "Nature", Francois Lebrun (CEA Saclay, Gif sur Yvette, France) and his collaborators report the discovery of 91 gamma-ray sources towards the direction of the Galactic centre. Lebrun's team includes Ubertini and seventeen other European scientists with long-standing experience in high-energy astrophysics. Much to the team's surprise, almost half of these sources do not fall in any class of known gamma-ray objects. They probably represent a new population of gamma-ray emitters. The first clues about a new class of gamma-ray objects came last October, when Integral discovered an intriguing gamma-ray source, known as IGRJ16318-4848. The data from Integral and ESA's other high-energy observatory XMM-Newton suggested that this object is a binary system, probably including a black hole or neutron star, embedded in a thick cocoon of cold gas and dust. When gas from the companion star is accelerated and swallowed by the black hole, energy is released at all wavelengths, mostly in the gamma rays. However, Lebrun is cautious to draw premature conclusions about the sources detected in the Galactic centre. Other interpretations are also possible that do not involve black holes. For instance, these objects could be the remains of exploded stars that are being energised by rapidly rotating celestial 'powerhouses', known as pulsars. Observations with another Integral instrument (SPI, the Spectrometer on Integral) could provide Lebrun and his team with more information on the nature of these sources. SPI measures the energy of incoming gamma rays with extraordinary accuracy and allows scientist to gain a better understanding of the physical mechanisms that generate them. However, regardless of the precise nature of these gamma-ray sources, Integral's observations have convincingly shown that the energy output from these new objects accounts for almost ninety per cent of the soft gamma-ray background coming from the centre of the Galaxy. This result raises the tantalising possibility that objects of this type hide everywhere in the Galaxy, not just in its centre. Again, Lebrun is cautious, saying, "It is tempting to think that we can simply extrapolate our results to the entire Galaxy. However, we have only looked towards its centre and that is a peculiar place compared to the rest." Next on Integral's list of things to do is to extend this work to the rest of the Galaxy. Christoph Winkler, ESA's Integral Project Scientist, says, "We now have to work on the whole disc region of the Galaxy. This will be a tough and long job for Integral. But at the end, the reward will be an exhaustive inventory of the most energetic celestial objects in the Galaxy." Note to editors The paper explaining these results will appear on the 18 March 2004 issue of "Nature". The author list includes F. Lebrun, R. Terrier, A. Bazzano, G. Belanger, A. Bird, L. Bouchet, A. Dean, M. Del Santo, A. Goldwurm, N. Lund, H. Morand, A. Parmar, J. Paul, J.-P. Roques, V. Schoenfelder, A. Strong, P. Ubertini, R. Walter and C. Winkler. For information about the related INTEGRAL and XMM-Newton discovery of IGRJ16318-4848, see: http://www.esa.int/esaSC/Pr_21_2003_s_en.html Integral The International Gamma Ray Astrophysics Laboratory (Integral) is the first space observatory that can simultaneously observe celestial objects in gamma rays, X-rays and visible light. Integral was launched on a Russian Proton rocket on 17 October 2002 into a highly elliptical orbit around Earth. Its principal targets include regions of the galaxy where chemical elements are being produced and compact objects, such as black holes. IBIS, Imager on Board the Integral Satellite - IBIS provides sharper gamma-ray images than any previous gamma-ray instrument. It can locate sources to a precision of 30 arcseconds, the equivalent of measuring the height of a person standing in a crowd, 1.3 kilometres away. The Principal Investigators that built the instrument are P. Ubertini (IAS/CNR, Rome, Italy), F. Lebrun (CEA Saclay, Gif sur Yvette, France), G. Di Cocco (ITESRE, Bologna, Italy). IBIS is equipped with the first un-cooled semiconductor gamma-ray camera, called ISGRI, which is responsible for its outstanding sensitivity. ISGRI was developed and built for ESA by CEA Saclay, France. SPI, Spectrometer on Integral - SPI measures the energy of incoming gamma rays with extraordinary accuracy. It is more sensitive to faint radiation than any previous gamma ray instrument and allows the precise nature of gamma ray sources to be determined. The Principal Investigators that developed SPI are J.-P. Roques, (CESR, Toulouse, France) and V. Schoenfelder (MPE, Garching, Germany). XMM-Newton XMM-Newton can detect more X-ray sources than any previous observatory and is helping to solve many cosmic mysteries of the violent Universe, from black holes to the formation of galaxies. It was launched on 10 December 1999, using an Ariane-5 rocket from French Guiana. Its orbit takes it almost a third of the way to the Moon, so that astronomers can enjoy long, uninterrupted views of celestial objects.

Evolution of black holes in the galaxy

NASA Astrophysics Data System (ADS)

Brown, G. E.; Lee, C.-H.; Wijers, R. A. M. J.; Bethe, H. A.

2000-08-01

In this article we consider the formation and evolution of black holes, especially those in binary stars where radiation from the matter falling on them can be seen. We consider a number of effects introduced by some of us, which are not traditionally included in binary evolution of massive stars. These are (i) hypercritical accretion, which allows neutron stars to accrete enough matter to collapse to a black hole during their spiral-in into another star. (ii) The strong mass loss of helium stars, which causes their evolution to differ from that of the helium core of a massive star. (iii) The direct formation of low-mass black holes (M~2Msolar) from single stars, a consequence of a significant strange-matter content of the nuclear-matter equation of state at high density. We discuss these processes here, and then review how they affect various populations of binaries with black holes and neutron stars. We have found that hypercritical accretion changes the standard scenario for the evolution of binary neutron stars: it now usually gives a black-hole, neutron-star (BH-NS) binary, because the first-born neutron star collapses to a low-mass black hole in the course of the evolution. A less probable double helium star scenario has to be introduced in order to form neutron-star binaries. The result is that low-mass black-hole, neutron star (LBH-NS) binaries dominate the rate of detectable gravity-wave events, say, by LIGO, by a factor /~20 over the binary neutron stars. The formation of high-mass black holes is suppressed somewhat due to the influence of mass loss on the cores of massive stars, raising the minimum mass for a star to form a massive BH to perhaps 80Msolar. Still, inclusion of high-mass black-hole, neutron-star (HBH-NS) binaries increases the predicted LIGO detection rate by another /~30% lowering of the mass loss rates of Wolf-Rayet stars may lower the HBH mass limit, and thereby further increase the merger rate. We predict that /~33 mergers per year will be observed with LIGO once the advanced detectors planned to begin in 2004 are in place. Black holes are also considered as progenitors for gamma ray bursters (GRB). Due to their rapid spin, potentially high magnetic fields, and relatively clean environment, mergers of black-hole, neutron-star binaries may be especially suitable. Combined with their 10 times greater formation rate than binary neutron stars this makes them attractive candidates for GRB progenitors, although the strong concentration of GRBs towards host galaxies may favor massive star progenitors or helium-star, black-hole mergers. We also consider binaries with a low-mass companion, and study the evolution of the very large number of black-hole transients, consisting of a black hole of mass ~7Msolar accompanied by a K or M main-sequence star (except for two cases with a somewhat more massive subgiant donor). We show that common envelope evolution must take place in the supergiant stage of the massive progenitor of the black hole, giving an explanation of why the donor masses are so small. We predict that there are about 22 times more binaries than observed, in which the main-sequence star, somewhat more massive than a K- or M-star, sits quietly inside its Roche Lobe, and will only become an X-ray source when the companion evolves off the main sequence. We briefly discuss the evolution of low-mass X-ray binaries into millisecond pulsars. We point out that in the usual scenario for forming millisecond pulsars with He white-dwarf companions, the long period of stable mass transfer will usually lead to the collapse of the neutron star into a black hole. We then discuss Van den Heuvel's ``Hercules X-1 scenario'' for forming low-mass X-ray binaries, commenting on the differences in accretion onto the compact object by radiative or semiconvective donors, rather than the deeply convective donors used in the earlier part of our review. In Appendix /A we describe the evolution of Cyg X-3, finding the compact object to be a black hole of ~3Msolar, together with an ~10Msolar He star. In Appendix /B we do the accounting for gravitational mergers and in Appendix /C we show low-mass black-hole, neutron-star binaries to be good progenitors for gamma ray bursters.

H.E.S.S. and CTA, present and perspectives in ground-based gamma-ray astronomy

NASA Astrophysics Data System (ADS)

Sol, H.

2016-12-01

Very high energy (VHE) gamma-ray astronomy emerged as a new branch of astronomy about ten years ago with the major discoveries achieved by the High Energy Stereocopic System (H.E.S.S.) operating in Namibia, quickly followed by the Major Atmospheric Gamma Imaging Cherenkov Telescopes (MAGIC) in the Canary Islands and the Very Energetic Radiation Imaging Telescope Array System (VERITAS) in the USA. These experiments succeeded to start exploring the cosmos at TeV energies, with the present detection of 178 sources in this range, mostly pulsar wind nebulae, supernova remnants, binary systems, blazars, and a variety of other types of sources. Based on these promizing results, the scientific community soon defined a next generation global project with significantly improved performance, the Cherenkov Telescope Array (CTA), in order to implement an open observatory at extreme energies, allowing a deep analysis of the sky in the highest part of the electromagnetic spectrum, from 20 GeV to 300 TeV. The CTA preparation phase is now completed. Production of the first telescopes should start in 2017 for deployment in 2018, in the perspective of an array fully operational at the horizon 2022.

An X-Ray Reprocessing Model of Disk Thermal Emission in Type 1 Seyfert Galaxies

NASA Technical Reports Server (NTRS)

Chiang, James; White, Nicholas E. (Technical Monitor)

2002-01-01

Using a geometry consisting of a hot central Comptonizing plasma surrounded by a thin accretion disk, we model the optical through hard X-ray spectral energy distributions of the type 1 Seyfert. galaxies NGC 3516 and NGC 7469. As in the model proposed by Poutanen, Krolik, and Ryde for the X-ray binary Cygnus X-1 and later applied to Seyfert galaxies by Zdziarski, Lubifiski, and Smith, feedback between the radiation reprocessed by the disk and the thermal Comptonization emission from the hot central plasma plays a pivotal role in determining the X-ray spectrum, and as we show, the optical and ultraviolet spectra as well. Seemingly uncorrelated optical/UV and X-ray light curves, similar to those which have been observed from these objects can, in principle, be explained by variations in the size, shape, and temperature of the Comptonizing plasma. Furthermore, by positing a disk mass accretion rate which satisfies a condition for global energy balance between the thermal Comptonization luminosity and the power available from accretion, one can predict the spectral properties of the heretofore poorly measured hard X-ray continuum above approximately 50 keV in type 1 Seyfert galaxies. Conversely, forthcoming measurements of the hard X-ray continuum by more sensitive hard X-ray and soft gamma-ray telescopes, such as those aboard the International Gamma-Ray Astrophysics Laboratory (INTEGRAL) in conjunction with simultaneous optical, UV, and soft X-ray monitoring, will allow the mass accretion rates to be directly constrained for these sources in the context of this model.

Techniques for Targeted Fermi-GBM Follow-Up of Gravitational-Wave Events

NASA Technical Reports Server (NTRS)

Blackburn, L.; Camp, J.; Briggs, M. S.; Connaughton, V.; Jenke, P.; Christensen, N.; Veitch, J.

2012-01-01

The Advanced LIGO and Advanced Virgo ground-based gravitational-wave (GW) detectors are projected to come online 2015 2016, reaching a final sensitivity sufficient to observe dozens of binary neutron star mergers per year by 2018. We present a fully-automated, targeted search strategy for prompt gamma-ray counterparts in offline Fermi-GBM data. The multi-detector method makes use of a detailed model response of the instrument, and benefits from time and sky location information derived from the gravitational-wave signal.

Cosmic matrix in the jubilee of relativistic astrophysics

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

Ruffini, R., E-mail: ruffini@icra.it; ICRANet, Piazza della Repubblica 10, I–65122 Pescara; Université de Nice Sophie Antipolis, Nice, CEDEX 2, Grand Château Parc Valrose

2015-12-17

Following the classical works on Neutron Stars, Black Holes and Cosmology, I outline some recent results obtained in the IRAP-PhD program of ICRANet on the “Cosmic Matrix”: a new astrophysical phenomenon recorded by the X- and Gamma-Ray satellites and by the largest ground based optical telescopes all over our planet. In 3 minutes it has been recorded the occurrence of a “Supernova”, the “Induced-Gravitational-Collapse” on a Neutron Star binary, the formation of a “Black Hole”, and the creation of a “Newly Born Neutron Star”. This presentation is based on a document describing activities of ICRANet and recent developments of themore » paradigm of the Cosmic Matrix in the comprehension of Gamma Ray Bursts (GRBs) presented on the occasion of the Fourteenth Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Gravitation, and Relativistic Field Theory. A Portuguese version of this document can be downloaded at: http://www.icranet.org/documents/brochure{sub i}cranet{sub p}t.pdf.« less

Long-term monitoring of blazars - the DWARF network

NASA Astrophysics Data System (ADS)

Backes, Michael; Biland, Adrian; Boller, Andrea; Braun, Isabel; Bretz, Thomas; Commichau, Sebastian; Commichau, Volker; Dorner, Daniela; von Gunten, Hanspeter; Gendotti, Adamo; Grimm, Oliver; Hildebrand, Dorothée; Horisberger, Urs; Krähenbühl, Thomas; Kranich, Daniel; Lustermann, Werner; Mannheim, Karl; Neise, Dominik; Pauss, Felicitas; Renker, Dieter; Rhode, Wolfgang; Rissi, Michael; Rollke, Sebastian; Röser, Ulf; Stark, Luisa Sabrina; Stucki, Jean-Pierre; Viertel, Gert; Vogler, Patrick; Weitzel, Quirin

The variability of the very high energy (VHE) emission from blazars seems to be connected with the feeding and propagation of relativistic jets and with their origin in supermassive black hole binaries. The key to understanding their properties is measuring well-sampled gamma-ray lightcurves, revealing the typical source behavior unbiased by prior knowledge from other wavebands. Using ground-based gamma-ray observatories with exposures limited by dark-time, a global network of several telescopes is needed to carry out fulltime measurements. Obviously, such observations are time-consuming and, therefore, cannot be carried out with the present state of the art instruments. The DWARF telescope on the Canary Island of La Palma is dedicated to monitoring observations. It is currently being set up, employing a costefficient and robotic design. Part of this project is the future construction of a distributed network of small telescopes. The physical motivation of VHE long-term monitoring will be outlined in detail and the perspective for a network for 24/7 observations will be presented.

Cosmic matrix in the jubilee of relativistic astrophysics

NASA Astrophysics Data System (ADS)

Ruffini, R.; Aimuratov, Y.; Belinski, V.; Bianco, C. L.; Enderli, M.; Izzo, L.; Kovacevic, M.; Mathews, G. J.; Moradi, R.; Muccino, M.; Penacchioni, A. V.; Pisani, G. B.; Rueda, J. A.; Vereshchagin, G. V.; Wang, Y.; Xue, S.-S.

2015-12-01

Following the classical works on Neutron Stars, Black Holes and Cosmology, I outline some recent results obtained in the IRAP-PhD program of ICRANet on the "Cosmic Matrix": a new astrophysical phenomenon recorded by the X- and Gamma-Ray satellites and by the largest ground based optical telescopes all over our planet. In 3 minutes it has been recorded the occurrence of a "Supernova", the "Induced-Gravitational-Collapse" on a Neutron Star binary, the formation of a "Black Hole", and the creation of a "Newly Born Neutron Star". This presentation is based on a document describing activities of ICRANet and recent developments of the paradigm of the Cosmic Matrix in the comprehension of Gamma Ray Bursts (GRBs) presented on the occasion of the Fourteenth Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Gravitation, and Relativistic Field Theory. A Portuguese version of this document can be downloaded at: http://www.icranet.org/documents/brochure_icranet_pt.pdf.

The Spectral Signatures Of BH Versus NS Sources

NASA Astrophysics Data System (ADS)

Seifina, E.; Titarchuk, L.

2011-09-01

We present a comparative analysis of spectral properties of Black Hole (BH) and Neutron Star (NS) X-ray binaries during transition events observed with BeppoSAX and RXTE satellites. In particular, we investigated the behavior of Comptonized component of X-ray spectra when object evolves from the low to high spectral states. The basic models to fit X-ray spectra of these objects are upscattering models (so called BMC and COMPTB models) which are the first principal models. These models taking into account both dynamical and thermal Comptonization and allow to study separate contributions of thermal component and Comptonization component (bulk and thermal effect of Comptonization processes). Specifically, we tested quite a few observations of BHs (GRS 1915+105 and SS 433) and NSs (4U 1728-34 and GX 3+1) applying BMC and COMPTB models. In this way it was found a crucial difference in behavior of photon index vs mass accretion rate (mdot) for BHs and NSs. Namely, we revealed the stability of the photon index around typical value of Gamma=2 versus mdot (or electron temperature) during spectral evolution of NS sources. This stability effect was previously suggested for a number of other neutron binaries (see Farinelli and Titarchuk, 2011). This intrinsic property of NS is fundamentally different from that in BH binary sources for which the index demonstrates monotonic growth with mass accretion rate followed by its saturation at high values of mdot. These index-mass accretion rate behavior during X-ray spectral transition events can be considered as signatures, which allow to differ NS from BH.

An Fe XXIV Absorption Line in the Persistent Spectrum of the Dipping Low-Mass X-Ray Binary 1A 1744-361

NASA Technical Reports Server (NTRS)

Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

2012-01-01

We report on Chandra X-ray Observatory (Chandra) High Energy Transmission Grating spectra of the dipping low-mass X-ray binary 1A 1744-361 during its 2008 July outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power law (Gamma approx. 1.7) with an absorption edge. In the residuals of the combined spectrum, we find a significant absorption line at 6.961 +/- 0.002 keV, consistent with the Fe xxvi (hydrogen-like Fe) 2-1 transition.We place an upper limit on the velocity of a redshifted flow of nu < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of (7 +/- 1)×10(exp 17) /sq. cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of >103.6 erg cm/s. We discuss what implications the feature has on the system and its geometry. We also present Rossi X-ray Timing Explorer data accumulated during this latest outburst and, via an updated color-color diagram, clearly show that 1A 1744-361 is an "atoll" source

A study on reducing the absorption of lidocaine from the airway in cats.

PubMed

Chen, Yunfeng; Zeng, Yiming; Zhang, Yin

2017-08-01

To determine if the combination of lidocaine with epinephrine or gamma globulin would decrease the rate or reduce the amount of local absorption of lidocaine through the airway. Twenty adult male cats were randomly and evenly distributed into four groups: 1) Group LG: lidocaine administered with gamma globulin; 2) Group LS: lidocaine administered with physiological saline); 3) Group LE: lidocaine administered with epinephrine; 4) Group C: control group. Invasive blood pressure, heart rate, and concentration of lidocaine were recorded before and after administration. The peak of plasma concentrations appeared difference (Group LG: 1.39 ± 0.23 mg/L; Group LS: 1.47 ± 0.29 mg/L and Group LE: 0.99 ± 0.08 mg/L). Compared to Group C, there were significant differences in the average heart rate of Groups LG, LS, and LE (P < 0.05). The average systolic blood pressures were significantly different when each group was compared to Group C (P < 0.05). The biological half-life, AUC0-120, peak time, and half-life of absorption among the three groups have not presented statistically significant differences (P > 0.05). Administering lidocaine in combination with gamma globulin through airway causes significant decrease the rate and reduce the amount of local absorption of lidocaine in cats.

Observation of Galactic Sources of Very High Energy γ-RAYS with the Magic Telescope

NASA Astrophysics Data System (ADS)

Bartko, H.

The MAGIC telescope with its 17m diameter mirror is today the largest operating single-dish Imaging Air Cherenkov Telescope (IACT). It is located on the Canary Island La Palma, at an altitude of 2200 m above sea level, as part of the Roque de los Muchachos European Northern Observatory. The MAGIC telescope detects celestial very high energy γ-radiation in the energy band between about 50 GeV and 10 TeV. Since the autumn of 2004 MAGIC has been taking data routinely, observing various objects, like supernova remnants (SNRs), γ-ray binaries, Pulsars, Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRB). We briefly describe the observational strategy, the procedure implemented for the data analysis, and discuss the results of observations of Galactic Sources.

The Burst and Transient Source Experiment(BATSE)Earth Occultation Catalog of Low-Energy Gamma-Ray Sources. Short title: BATSE Earth Occultation Catalog v2.0

NASA Technical Reports Server (NTRS)

Harmon, B. A.; Wilson, C. A.; Fishman, G. J.; Connaughton, V.; Henze, W.; Paciesas, W. S.; Finger, M. H.; McCollough, M. L.; Sahi, M.; Peterson, B.

2003-01-01

The Burst and Transient Source Experiment (BATSE), aboard the Compton Gamma Ray Observatory (CGRO), provided a record of the low-energy gamma-ray sky (approx. 20-1000 keV) between 1991 April and 2000 May (9.1y). BATSE monitored the high energy sky using the Earth occultation technique (EOT) for point sources whose emission extended for times on the order of the CGRO orbital period (approx. 92m) or greater. Using the EOT to extract flux - 2 - information, a catalog of sources using data from the BATSE large area detectors has been prepared. The first part of the catalog consists of results from the all-sky monitoring of 58 sources, mostly Galactic, with intrinsic variability on timescales of hours to years. For these sources, we have included tables of flux and spectral data, and outburst times for transients. Light curves (or flux histories) covering the entire nine mission are being placed on the world wide web. We then performed a deep-sampling of these 58 objects, plus a selection of 121 more objects, combining data from the entire 9.ly BATSE dataset. Source types considered were primarily accreting binaries, but a small number of representative active galaxies, X-ray-emitting stars, and supernova remnants were also included. The sample represents a compilation of sources monitored and/or discovered with BATSE and other high energy instruments between 1991 and 2000, known sources taken from the HEAO 1 A-4 (Levine et al. 1984) and Macomb and Gehrels (1999) catalogs. The deep sample results include definite detections of 82 objects and possible detections of 36 additional objects. The definite detections spanned three classes of sources: accreting black hole and neutron star binaries, active galaxies and supernova remnants. The average fluxes measured for the fourth class, the X-ray emitting stars, were below the confidence limit for definite detection. Flux data for the deep sample are presented in four energy bands: 20-40, 40-70, 70-160, and 160-430 keV. The limiting average flux level (9.1 y) for the sample varies from 3.5 to 20 mCrab (5delta) between 20 and 430 keV, depending on systematic error, which in turn is primarily dependent on the sky location. To strengthen the credibility of detection of weaker sources (approx.5-25 mCrab), we generated Earth occultation images, searched for periodic behavior using FFT and epoch folding methods, and critically evaluated the energy-dependent emission in the four flux bands. The deep sample results are intended for guidance in performing future all-sky surveys or pointed observations in the hard X-ray and low-energy gamma-ray band, as well as more detailed studies with the BATSE EOT.

Astronomy in Denver: Spectropolarimetric Observations of 5 Wolf-Rayet Binary Stars with SALT/RSS

NASA Astrophysics Data System (ADS)

Fullard, Andrew; Ansary, Zyed; Azancot Luchtan, Daniel; Gallegos, Hunter; Luepker, Martin; Hoffman, Jennifer L.; Nordsieck, Kenneth H.; SALT observation team

2018-06-01

Mass loss from massive stars is an important yet poorly understood factor in shaping their evolution. Wolf-Rayet (WR) stars are of particular interest due to their stellar winds, which create large regions of circumstellar material (CSM). They are also supernova and possible gamma-ray burst (GRB) progenitors. Like other massive stars, WR stars often occur in binaries, where interaction can affect their mass loss rates and provide the rapid rotation thought to be required for GRB production. The diagnostic tool of spectropolarimetry, along with the potentially eclipsing nature of a binary system, helps us to better characterize the CSM created by the stars’ colliding winds. Thus, we can determine mass loss rates and infer rapid rotation. We present spectropolarimetric results for five WR+O eclipsing binary systems, obtained with the Robert Stobie Spectrograph at the South African Large Telescope, between April 2017 and April 2018. The data allow us to map both continuum and emission line polarization variations with phase, which constrains where different CSM components scatter light in the systems. We discuss our initial findings and interpretations of the polarimetric variability in each binary system, and compare the systems.

The Blazar PG 1553+113 as a Binary System of Supermassive Black Holes

NASA Astrophysics Data System (ADS)

Tavani, M.; Cavaliere, A.; Munar-Adrover, Pere; Argan, A.

2018-02-01

The BL Lac PG 1553+113 has been continuously monitored in gamma-rays with Fermi-LAT for over 9 years. Its updated light curve now includes five iterations of a main pattern comprising a high peak and a longer trough, with a period P≃ 2.2 {year}. Our analysis of 2015–2017 data confirms the occurrence in 2017 January of a new peak fitting in with the previous trend. In addition, we identify secondary peaks (“twin peaks”) that occur in closely symmetric pairs on both sides of most main peaks, including the last one; their occurrence is supported by correlated X-ray outbursts. We stress that the above features strongly point to binary dynamics in a system of two black holes (BHs) of some 108 and {10}7 {M}ȯ . At periastron the smaller BH periodically stresses the jet j 1 launched by the heavier companion, and triggers MHD–kinetic tearing instabilities. These lead to magnetic reconnections and to acceleration of electrons that produce synchrotron emission from the optical to X-ray bands, and inverse Compton scattering into the GeV range. We discuss two possible origins of the twin peaks : a single-jet model, based on added instabilities induced in j 1 by the smaller companion BH on its inner orbital arc; and a two-jet model with the smaller BH supporting its own, precessing jet j 2 that contributes lower, specific GeV emissions. Such behaviors combining time stability with amplitude variations betray plasma instabilities driven in either jet by binary dynamics, and can provide a double signature of the long-sought supermassive BH binaries.

A PROPELLER MODEL FOR THE SUB-LUMINOUS STATE OF THE TRANSITIONAL MILLISECOND PULSAR PSR J1023+0038

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

Papitto, A.; Torres, D. F.

The discovery of millisecond pulsars switching between states powered either by the rotation of their magnetic field or by the accretion of matter has recently proved the tight link shared by millisecond radio pulsars and neutron stars in low-mass X-ray binaries. Transitional millisecond pulsars also show an enigmatic intermediate state in which the neutron star is surrounded by an accretion disk and emits coherent X-ray pulsations, but is sub-luminous in X-rays with respect to accreting neutron stars, and is brighter in gamma-rays than millisecond pulsars in the rotation-powered state. Here, we model the X-ray and gamma-ray emission observed from PSR J1023+0038more » in such a state based on the assumptions that most of the disk in-flow is propelled away by the rapidly rotating neutron star magnetosphere, and that electrons can be accelerated to energies of a few GeV at the turbulent disk–magnetosphere boundary. We show that the synchrotron and self-synchrotron Compton emission coming from such a region, together with the hard disk emission typical of low states of accreting compact objects, is able to explain the radiation observed in the X-ray and gamma-ray bands. The average emission observed from PSR J1023+0038 is modeled by a disk in-flow with a rate of 1–3 × 10{sup −11} M{sub ⊙} yr{sup −1}, truncated at a radius ranging between 30 and 45 km, compatible with the hypothesis of a propelling magnetosphere. We compare the results we obtained with models that assume that a rotation-powered pulsar is turned on, showing how the spin-down power released in similar scenarios is hardly able to account for the magnitude of the observed emission.« less

Prediagnostic Smoking Is Associated with Binary and Quantitative Measures of ER Protein and ESR1 mRNA Expression in Breast Tumors.

PubMed

Butler, Eboneé N; Bensen, Jeannette T; Chen, Mengjie; Conway, Kathleen; Richardson, David B; Sun, Xuezheng; Geradts, Joseph; Olshan, Andrew F; Troester, Melissa A

2018-01-01

Background: Smoking is a possible risk factor for breast cancer and has been linked to increased risk of estrogen receptor-positive (ER + ) disease in some epidemiologic studies. It is unknown whether smoking has quantitative effects on ER expression. Methods: We examined relationships between smoking and ER expression from tumors of 1,888 women diagnosed with invasive breast cancer from a population-based study in North Carolina. ER expression was characterized using binary (±) and continuous measures for ER protein, ESR1 mRNA, and a multigene luminal score (LS) that serves as a measure of estrogen signaling in breast tumors. We used logistic and linear regression models to estimate temporal and dose-dependent associations between smoking and ER measures. Results: The odds of ER + , ESR1 + , and LS + tumors among current smokers (at the time of diagnosis), those who smoked 20 or more years, and those who smoked within 5 years of diagnosis were nearly double those of nonsmokers. Quantitative levels of ESR1 were highest among current smokers compared with never smokers overall [mean (log 2 ) = 9.2 vs. 8.7, P < 0.05] and among ER + cases; however, we did not observe associations between smoking measures and continuous ER protein expression. Conclusions: In relationship to breast cancer diagnosis, recent smoking was associated with higher odds of the ER + , ESR1 + , and LS + subtype. Current smoking was associated with elevated ESR1 mRNA levels and an elevated LS, but not with altered ER protein. Impact: A multigene LS and single-gene ESR1 mRNA may capture tumor changes associated with smoking. Cancer Epidemiol Biomarkers Prev; 27(1); 67-74. ©2017 AACR . ©2017 American Association for Cancer Research.

Young and Old X-ray Binary and IXO Populations in Spiral and Elliptical Galaxies

NASA Astrophysics Data System (ADS)

Colbert, E.; Heckman, T.; Ptak, A.; Strickland, D.; Weaver, K.

2003-03-01

We have analyzed Chandra ACIS observations of 32 nearby spiral and elliptical galaxies and present the results of 1441 X-ray point sources, which are presumed to be mostly X-ray binaries (XRBs) and Intermediate-luminosity X-ray Objects (IXOs, a.k.a. ULXs). The X-ray luminosity functions (XLFs) of the point sources show that the slope of the elliptical galaxy XLFs are significantly steeper than the spiral galaxy XLFs, indicating grossly different types of point sources, or different stages in their evolution. Since the spiral galaxy XLF is so shallow, the most luminous points sources (usually the IXOs) dominate the total X-ray point source luminosity LXP. We show that the galaxy total B-band and K-band light (proxies for the stellar mass) are well correlated with LXP for both spirals and ellipticals, but the FIR and UV emission is only correlated for the spirals. We deconvolve LXP into two components, one that is proportional to the galaxy stellar mass (pop II), and another that is proportional to the galaxy SFR (pop I). We also note that IXOs (and nearly all of the other point sources) in both spirals and ellipticals have X-ray colors that are most consistent with power-law slopes of Gamma ˜ 1.5--3.0, which is inconsistent with high-mass XRBS (HMXBs). Thus, HMXBs are not important contributors to LXP. We have also found that IXOs in spiral galaxies may have a slightly harder X-ray spectrum than those in elliptical galaxies. The implications of these findings will be discussed.

A new 4π(LS)-γ coincidence counter at NCBJ RC POLATOM with TDCR detector in the beta channel.

PubMed

Ziemek, T; Jęczmieniowski, A; Cacko, D; Broda, R; Lech, E

2016-03-01

A new 4π(LS)-γ coincidence system (TDCRG) was built at the NCBJ RC POLATOM. The counter consists of a TDCR detector in the beta channel and scintillation detector with NaI(Tl) crystal in the gamma channel. The system is equipped with a digital board with FPGA, which records and analyses coincidences in the TDCR detector and coincidences between the beta and gamma channels. The characteristics of the system and a scheme of the FPGA implementation with behavioral simulation are given. The TDCRG counter was validated by activity measurements on (14)C and (60)Co solutions standardized in RC POLATOM using previously validated methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

Probing extra dimension through gravitational wave observations of compact binaries and their electromagnetic counterparts

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

Yu, Hao; Gu, Bao-Min; Wang, Yong-Qiang

The future gravitational wave (GW) observations of compact binaries and their possible electromagnetic counterparts may be used to probe the nature of the extra dimension. It is widely accepted that gravitons and photons are the only two completely confirmed objects that can travel along null geodesics in our four-dimensional space-time. However, if there exist extra dimensions and only GWs can propagate freely in the bulk, the causal propagations of GWs and electromagnetic waves (EMWs) are in general different. In this paper, we study null geodesics of GWs and EMWs in a five-dimensional anti-de Sitter space-time in the presence of themore » curvature of the universe. We show that for general cases the horizon radius of GW is longer than EMW within equal time. Taking the GW150914 event detected by the Advanced Laser Interferometer Gravitational-Wave Observatory and the X-ray event detected by the Fermi Gamma-ray Burst Monitor as an example, we study how the curvature k and the constant curvature radius l affect the horizon radii of GW and EMW in the de Sitter and Einstein-de Sitter models of the universe. This provides an alternative method for probing extra dimension through future GW observations of compact binaries and their electromagnetic counterparts.« less

High Energy Observational Investigations of Supernova Remnants and their Interactions with Surroundings

NASA Astrophysics Data System (ADS)

Hui, Chung-Yue

2013-09-01

Here we review the effort of Fermi Asian Network (FAN) in exploring the supernova remnants (SNRs) with state-of-art high energy observatories, including Fermi Gamma-ray Space Telescope and Chandra X-ray Observatory, in the period of 2011- 2012. Utilizing the data from Fermi LAT, we have discovered the GeV emission at the position of the Galactic SNR Kes 17 which provides evidence for the hadronic acceleration. Our study also sheds light on the propagation of cosmic rays from their acceleration site to the intersteller medium. We have also launched an identification campaign of SNR candidates in the Milky Way, in which a new SNR G308.3-1.4 have been uncovered with our Chandra observation. Apart from the remnant, we have also discovered an associated compact object at its center. The multiwavelength properties of this X-ray source suggest it can possibly be the compact binary that survived a supernova explosion.

Detection and period measurements of GX1+4 at hard x ray energies with the SIGMA telescope

NASA Technical Reports Server (NTRS)

Laurent, PH.; Salotti, L.; Lebrun, F.; Paul, J.; Denis, M.; Barret, D.; Jourdain, E.; Roques, J. P.; Churazov, E.; Gilfanov, M.

1992-01-01

The galactic Low Mass X ray Binary GX1+4 was detected by the coded aperture hard X ray gamma ray SIGMA telescope during the Feb. to April 1991 observations of the galactic center regions. The source, whose emission varied during the survey of a factor greater than 40 pct., reached a maximum luminosity in the 40 to 140 energy range of 1.03 x 10(exp 37) erg/s (D = 8.5 kpc), thus approaching the emission level of the 1970 to 1980 high state. Two minute flux pulsations were detected on Mar. 22 and on Mar. 31 and Apr. 1. Comparison with the last period measurements shows that the current spin-down phase of GX1+4 is ending. Concerning the proposed association of this source with the galactic center 511 keV annihilation emission, upper limits were derived.

Gamma-Ray Emission Concurrent with the Nova in the Symbiotic Binary V407 Cygni

DOE PAGES

Abdo, A. A.; Ackermann, M.; Ajello, M.; ...

2010-08-13

Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here in this paper, we report the Fermi Large Area Telescope detection of variable γ-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particlesmore » can be accelerated effectively to produce π 0 decay γ-rays from proton-proton interactions. Lastly, emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.« less

The Diversity of Kilonova Emission in Short Gamma-Ray Bursts

NASA Astrophysics Data System (ADS)

Gompertz, B. P.; Levan, A. J.; Tanvir, N. R.; Hjorth, J.; Covino, S.; Evans, P. A.; Fruchter, A. S.; González-Fernández, C.; Jin, Z. P.; Lyman, J. D.; Oates, S. R.; O’Brien, P. T.; Wiersema, K.

2018-06-01

The historic first joint detection of both gravitational-wave and electromagnetic emission from a binary neutron star merger cemented the association between short gamma-ray bursts (SGRBs) and compact object mergers, as well as providing a well-sampled multi-wavelength light curve of a radioactive kilonova (KN) for the first time. Here, we compare the optical and near-infrared light curves of this KN, AT 2017gfo, to the counterparts of a sample of nearby (z < 0.5) SGRBs to characterize their diversity in terms of their brightness distribution. Although at similar epochs AT 2017gfo appears fainter than every SGRB-associated KN claimed so far, we find three bursts (GRBs 050509B, 061201, and 080905A) where, if the reported redshifts are correct, deep upper limits rule out the presence of a KN similar to AT 2017gfo by several magnitudes. Combined with the properties of previously claimed KNe in SGRBs this suggests considerable diversity in the properties of KN drawn from compact object mergers, despite the similar physical conditions that are expected in many NS–NS mergers. We find that observer angle alone is not able to explain this diversity, which is likely a product of the merger type (NS–NS versus NS–BH) and the detailed properties of the binary (mass ratio, spins etc.). Ultimately disentangling these properties should be possible through observations of SGRBs and gravitational-wave sources, providing direct measurements of heavy element enrichment throughout the universe.

The Properties of Short Gamma-Ray Burst Jets Triggered by Neutron Star Mergers

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

Murguia-Berthier, Ariadna; Ramirez-Ruiz, Enrico; Montes, Gabriela

The most popular model for short gamma-ray bursts (sGRBs) involves the coalescence of binary neutron stars. Because the progenitor is actually hidden from view, we must consider under which circumstances such merging systems are capable of producing a successful sGRB. Soon after coalescence, winds are launched from the merger remnant. In this paper, we use realistic wind profiles derived from global merger simulations in order to investigate the interaction of sGRB jets with these winds using numerical simulations. We analyze the conditions for which these axisymmetric winds permit relativistic jets to break out and produce an sGRB. We find thatmore » jets with luminosities comparable to those observed in sGRBs are only successful when their half-opening angles are below ≈20°. This jet collimation mechanism leads to a simple physical interpretation of the luminosities and opening angles inferred for sGRBs. If wide, low-luminosity jets are observed, they might be indicative of a different progenitor avenue such as the merger of a neutron star with a black hole. We also use the observed durations of sGRB to place constraints on the lifetime of the wind phase, which is determined by the time it takes the jet to break out. In all cases we find that the derived limits argue against completely stable remnants for binary neutron star mergers that produce sGRBs.« less

The GW170817/GRB 170817A/AT 2017gfo Association: Some Implications for Physics and Astrophysics

NASA Astrophysics Data System (ADS)

Wang, Hao; Zhang, Fu-Wen; Wang, Yuan-Zhu; Shen, Zhao-Qiang; Liang, Yun-Feng; Li, Xiang; Liao, Neng-Hui; Jin, Zhi-Ping; Yuan, Qiang; Zou, Yuan-Chuan; Fan, Yi-Zhong; Wei, Da-Ming

2017-12-01

On 2017 August 17, a gravitational-wave event (GW170817) and an associated short gamma-ray burst (GRB 170817A) from a binary neutron star merger had been detected. The follow-up optical/infrared observations also identified the macronova/kilonova emission (AT 2017gfo). In this work, we discuss some implications of the remarkable GW170817/GRB 170817A/AT 2017gfo association. We show that the ∼1.7 s time delay between the gravitational-wave (GW) and GRB signals imposes very tight constraints on the superluminal movement of gravitational waves (i.e., the relative departure of GW velocity from the speed of light is ≤slant 4.3× {10}-16) or the possible violation of the weak equivalence principle (i.e., the difference of the gamma-ray and GW trajectories in the gravitational field of the galaxy and the local universe should be within a factor of ∼ 3.4× {10}-9). The so-called Dark Matter Emulators and a class of contender models for cosmic acceleration (“Covariant Galileon”) are ruled out as well. The successful identification of lanthanide elements in the macronova/kilonova spectrum also excludes the possibility that the progenitors of GRB 170817A are a binary strange star system. The high neutron star merger rate (inferred from both the local sGRB data and the gravitational-wave data) together with the significant ejected mass strongly suggest that such mergers are the prime sites of heavy r-process nucleosynthesis.

PROSPECTS FOR JOINT GRAVITATIONAL WAVE AND SHORT GAMMA-RAY BURST OBSERVATIONS

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

Clark, J.; Evans, H.; Fairhurst, S.

2015-08-10

We present a detailed evaluation of the expected rate of joint gravitational-wave (GW) and short gamma-ray burst (GRB) observations over the coming years. We begin by evaluating the improvement in distance sensitivity of the GW search that arises from using the GRB observation to restrict the time and sky location of the source. We argue that this gives a 25% increase in sensitivity when compared to an all-sky, all-time search, corresponding to more than double the number of detectable GW signals associated with GRBs. Using this, we present the expected rate of joint observations with the advanced LIGO and Virgomore » instruments, taking into account the expected evolution of the GW detector network. We show that in the early advanced GW detector observing runs, from 2015 to 2017, there is only a small chance of a joint observation. However, as the detectors approach their design sensitivities, there is a good chance of joint observations, provided wide field GRB satellites, such as Fermi and the Inter planetary Network, continue operation. The rate will also depend critically upon the nature of the progenitor, with neutron star-black hole systems observable to greater distances than double neutron star systems. The relative rate of binary mergers and GRBs will depend upon the jet opening angle of GRBs. Consequently, joint observations, as well as accurate measurement of both the GRB rate and binary merger rates, will allow for an improved estimation of the opening angle of GRBs.« less

ANSL-V: ENDF/B-V based multigroup cross-section libraries for Advanced Neutron Source (ANS) reactor studies. Supplement 1

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

Wright, R.Q.; Renier, J.P.; Bucholz, J.A.

1995-08-01

The original ANSL-V cross-section libraries (ORNL-6618) were developed over a period of several years for the physics analysis of the ANS reactor, with little thought toward including the materials commonly needed for shielding applications. Materials commonly used for shielding applications include calcium barium, sulfur, phosphorous, and bismuth. These materials, as well as {sup 6}Li, {sup 7}Li, and the naturally occurring isotopes of hafnium, have been added to the ANSL-V libraries. The gamma-ray production and gamma-ray interaction cross sections were completely regenerated for the ANSL-V 99n/44g library which did not exist previously. The MALOCS module was used to collapse the 99n/44gmore » coupled library to the 39n/44g broad- group library. COMET was used to renormalize the two-dimensional (2- D) neutron matrix sums to agree with the one-dimensional (1-D) averaged values. The FRESH module was used to adjust the thermal scattering matrices on the 99n/44g and 39n/44g ANSL-V libraries. PERFUME was used to correct the original XLACS Legendre polynomial fits to produce acceptable distributions. The final ANSL-V 99n/44g and 39n/44g cross-section libraries were both checked by running RADE. The AIM module was used to convert the master cross-section libraries from binary coded decimal to binary format (or vice versa).« less

Afterglows and Kilonovae Associated with Nearby Low-luminosity Short-duration Gamma-Ray Bursts: Application to GW170817/GRB 170817A

NASA Astrophysics Data System (ADS)

Xiao, Di; Liu, Liang-Duan; Dai, Zi-Gao; Wu, Xue-Feng

2017-12-01

Very recently, the gravitational-wave (GW) event GW170817 was discovered to be associated with the short gamma-ray burst (GRB) 170817A. Multi-wavelength follow-up observations were carried out, and X-ray, optical, and radio counterparts to GW170817 were detected. The observations undoubtedly indicate that GRB 170817A originates from a binary neutron star merger. However, the GRB falls into the low-luminosity class that could have a higher statistical occurrence rate and detection probability than the normal (high-luminosity) class. This implies the possibility that GRB 170817A is intrinsically powerful, but we are off-axis and only observe its side emission. In this Letter, we provide a timely modeling of the multi-wavelength afterglow emission from this GRB and the associated kilonova signal from the merger ejecta, under the assumption of a structured jet, a two-component jet, and an intrinsically less-energetic quasi-isotropic fireball, respectively. Comparing the afterglow properties with the multi-wavelength follow-up observations, we can distinguish between these three models. Furthermore, a few model parameters (e.g., the ejecta mass and velocity) can be constrained.

Application of the Double-Tangent Construction of Coexisting Phases to Any Type of Phase Equilibrium for Binary Systems Modeled with the Gamma-Phi Approach

ERIC Educational Resources Information Center

Jaubert, Jean-Noël; Privat, Romain

2014-01-01

The double-tangent construction of coexisting phases is an elegant approach to visualize all the multiphase binary systems that satisfy the equality of chemical potentials and to select the stable state. In this paper, we show how to perform the double-tangent construction of coexisting phases for binary systems modeled with the gamma-phi…

Searches for Periodic Neutrino Emission from Binary Systems with 22 and 40 Strings of IceCube

NASA Technical Reports Server (NTRS)

Abassi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Allen, M. M.; Altmann, D.; Andeen, K.;

SMM observations of gamma-ray transients. 3: A search for a broadened, redshifted positron annihilation line from the direction of the Galactic center

NASA Technical Reports Server (NTRS)

Harris, Michael J.; Share, Gerald H.; Leising, Mark D.

1994-01-01

We have searched for 1980-1988 Solar Maximum Mission gamma-ray spectrometer data for transient emission on timescales from hours to approximately 12 days of broad gamma-ray lines at energies approximately 400 keV, which were reported by the High Energy Astronomy Observatory (HEAO) 1 and SIGMA experiments from two sources lying toward the Galactic center. The lines have been interpreted as the product of the annihilation of positrons in pair plasmas surrounding the black hole candidate 1E 1740.7-2942 and the X-ray binary 1H 1822-371. Our results from a combined exposure of approximately 1.5 x 10(exp 7)s provide no convincing evidence for transient emission of this line on any timescale between approximately 9 hr and approximately 1 yr. Our 3 sigma upper limits on the line flux during approximately 12 day intervals are characteristically 4.8 x 10(exp -3) photon/sq cm/s, while for approximately 1 day intervals our 3 sigma upper limits are characteristically 4.9 x 10(exp -3) photon/sq cm/s. These results imply a duty cycle of less than 1.3% for the transient line measured from 1H 1822-371 during a approximately 3 week interval in 1977 by HEAO 1, and a duty cycle of less than or = 0.8% for the transient line detected in 1990 and 1992 from 1E 1740.7-2942 on approximately 1 day timescales by SIGMA.

Hadronic gamma-ray and neutrino emission from Cygnus X-3

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

Sahakyan, N.; Piano, G.; Tavani, M., E-mail: narek@icra.it

2014-01-01

Cygnus X-3 (Cyg X-3) is a remarkable Galactic microquasar (X-ray binary) emitting from radio to γ-ray energies. In this paper, we consider the hadronic model of emission of γ-rays above 100 MeV and their implications. We focus on the joint γ-ray and neutrino production resulting from proton-proton interactions within the binary system. We find that the required proton injection kinetic power, necessary to explain the γ-ray flux observed by AGILE and Fermi-LAT, is L{sub p} ∼ 10{sup 38} erg s{sup –1}, a value in agreement with the average bolometric luminosity of the hypersoft state (when Cyg X-3 was repeatedly observedmore » to produce transient γ-ray activity). If we assume an increase of the wind density at the superior conjunction, the asymmetric production of γ-rays along the orbit can reproduce the observed modulation. According to observational constraints and our modeling, a maximal flux of high-energy neutrinos would be produced for an initial proton distribution with a power-law index α = 2.4. The predicted neutrino flux is almost two orders of magnitude less than the two-month IceCube sensitivity at ∼1 TeV. If the protons are accelerated up to PeV energies, the predicted neutrino flux for a prolonged 'soft X-ray state' would be a factor of about three lower than the one-year IceCube sensitivity at ∼10 TeV. This study shows that, for a prolonged soft state (as observed in 2006) possibly related to γ-ray activity and a hard distribution of injected protons, Cyg X-3 might be close to being detectable by cubic-kilometer neutrino telescopes such as IceCube.« less

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.

Probing Neutron Star Evolution with Gamma Rays

NASA Astrophysics Data System (ADS)

Wijers, Ralph A. M. J.

1996-02-01

The research sponsored by this grant was conducted in two fields of high-energy astrophysics: gamma-ray bursts and evolution of neutron stars. It is unknown at this time whether they are related. The work performed in each area is discussed followed by a full list of publications supported by the grant. My research (with E. Fenimore, L. Lubin, B. Paczyiiski, and A. Ulmer) has focussed on devising tests that could distinguish between BATSE and galactic-halo distance scales using the available data. In the first instance, the issue was whether the early BATSE peak flux distribution could be used to extract more than just a slope of the log N(greater than P) distribution, and whether it joined smoothly to the steeper peak flux distribution of bright bursts. To this end, we analysed the peak flux distribution for the presence of a change in slope. This was done both by fitting models with a core radius to see whether a significant value for it could be found, and by developing a completely model-independent test to search for slope changes in arbitrary distributions that are nearly power laws. A slope change was marginally detected in the first-year BATSE data. Good progress has been made in understanding the evolution of neutron stars and their magnetic fields. Having shown in earlier work that magnetic fields in some neutron stars, particularly Her X-1, do not decay spontaneously on million-year time scales, we set out to check whether such spontaneous decay was needed in isolated radio pulsars, as claimed by many. We found that it is not; rather long decay times or no decay are preferred. Since there are neutron stars with low magnetic fields, one must conclude that there is something in their past that distinguishes them from most pulsars. These so-called recycled pulsars are in binaries much more often than normal pulsars. My research concentrates on the class of scenarios in which the recycled pulsars are initially the same as ordinary high-field radio pulsars, and have acquired their properties due to mass transfer processes in binary stars. This links their evolution to that of X-ray binaries.

Bin-Carver: Automatic Recovery of Binary Executable Files

DTIC Science & Technology

2012-05-01

PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Texas A&M University,Department of Computer Science and Engineering,College Station,TX,77840 8...PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT...least 23 4K data blocks) and observed how this binary file gets organized in a brand new disk. We found that this simple ls file actually gets

Where Angels Fear To Tread

ERIC Educational Resources Information Center

Smyth, A. J. M.

1970-01-01

Presents a research project for secondary school students in the fields of archaeophysics (archaeology) and geophysics using gamma spectroscopy. Describes investigations in mineralization and in dating of potsherds. (LS)

Multi-particle inspection using associated particle sources

DOEpatents

Bingham, Philip R.; Mihalczo, John T.; Mullens, James A.; McConchie, Seth M.; Hausladen, Paul A.

2016-02-16

Disclosed herein are representative embodiments of methods, apparatus, and systems for performing combined neutron and gamma ray radiography. For example, one exemplary system comprises: a neutron source; a set of alpha particle detectors configured to detect alpha particles associated with neutrons generated by the neutron source; neutron detectors positioned to detect at least some of the neutrons generated by the neutron source; a gamma ray source; a set of verification gamma ray detectors configured to detect verification gamma rays associated with gamma rays generated by the gamma ray source; a set of gamma ray detectors configured to detect gamma rays generated by the gamma ray source; and an interrogation region located between the neutron source, the gamma ray source, the neutron detectors, and the gamma ray detectors.

Observations of VHE γ-Ray Sources with the MAGIC Telescope

NASA Astrophysics Data System (ADS)

Bartko, H.

2008-10-01

The MAGIC telescope with its 17m diameter mirror is today the largest operating single-dish Imaging Air Cherenkov Telescope (IACT). It is located on the Canary Island La Palma, at an altitude of 2200m above sea level, as part of the Roque de los Muchachos European Northern Observatory. The MAGIC telescope detects celestial very high energy γ-radiation in the energy band between about 50 GeV and 10 TeV. Since Autumn of 2004 MAGIC has been taking data routinely, observing various objects like supernova remnants (SNRs), γ-ray binaries, Pulsars, Active Galactic Nuclei (AGN) and Gamma-ray Bursts (GRB). We briefly describe the observational strategy, the procedure implemented for the data analysis, and discuss the results for individual sources. An outlook to the construction of the second MAGIC telescope is given.

On the Dramatic Spin-up/Spin-Down Torque Reversals in Accreting Pulsars

NASA Technical Reports Server (NTRS)

Nelson, Robert W.; Bildsten, Lars; Chakrabarty, Deepto; Finger, Mark H.; Koh, Danny T.; Prince, Thomas A.; Rubin, Bradley C.; Scott, D. Mathew; Vaughan, Brian A.; Wilson, Robert B.

1997-01-01

Dramatic torque reversals between spin-up and spin-down have been observed in half of the persistent X-ray pulsars monitored by the Burst and Transient Space Experiment (BATSE) all-sky monitor on the Compton Gamma Ray Observatory. Theoretical models developed to explain early pulsar timing data can explain spin-down torques via a disk-magnetosphere interaction if the star nearly corotates with the inner accretion disk. To produce the observed BATSE torque reversals, however, these equilibrium models require the disk to alternate between two mass accretion rates, with M+/- producing accretion torques of similar magnitude but always of opposite sign. Moreover, in at least one pulsar (GX 1+4) undergoing secular spin-down, the neutron star spins down faster during brief (approximately 20 day) hard X-ray flares-this is opposite the correlation expected from standard theory, assuming that BATSE pulsed flux increases with mass accretion rate. The 10 day to 10 yr intervals between torque reversals in these systems are much longer than any characteristic magnetic or viscous timescale near the inner disk boundary and are more suggestive of a global disk phenomenon. We discuss possible explanations of the observed torque behavior. Despite the preferred sense of rotation defined by the binary orbit, the BATSE observations are surprisingly consistent with an earlier suggestion for GX 1+4: the disks in these systems somehow alternate between episodes of prograde and retrograde rotation. We are unaware of any mechanism that could produce a stable retrograde disk in a binary undergoing Roche lobe overflow, but such flip-flop behavior does occur in numerical simulations of wind-fed systems. One possibility is that the disks in some of these binaries are fed by an X-ray-excited wind.

Effects of Correlated and Uncorrelated Gamma Rays on Neutron Multiplicity Counting

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

Cowles, Christian C.; Behling, Richard S.; Imel, George R.

Neutron multiplicity counting relies on time correlation between neutron events to assay the fissile mass, (α,n) to spontaneous fission neutron ratio, and neutron self-multiplication of samples. Gamma-ray sensitive neutron multiplicity counters may misidentify gamma rays as neutrons and therefore miscalculate sample characteristics. Time correlated and uncorrelated gamma-ray-like signals were added into gamma-ray free neutron multiplicity counter data to examine the effects of gamma ray signals being misidentified as neutron signals on assaying sample characteristics. Multiplicity counter measurements with and without gamma-ray-like signals were compared to determine the assay error associated with gamma-ray-like signals at various gamma-ray and neutron rates. Correlatedmore » and uncorrelated gamma-ray signals each produced consistent but different measurement errors. Correlated gamma-ray signals most strongly led to fissile mass overestimates, whereas uncorrelated gamma-ray signals most strongly lead to (α,n) neutron overestimates. Gamma-ray sensitive neutron multiplicity counters may be able to account for the effects of gamma-rays on measurements to mitigate measurement uncertainties.« less

Recent progress in understanding the eruptions of classical novae

NASA Technical Reports Server (NTRS)

Shara, Michael M.

1988-01-01

Dramatic progress has occurred in the last two decades in understanding the physical processes and events leading up to, and transpiring during the eruption of a classical nova. The mechanism whereby a white dwarf accreting hydrogen-rich matter from a low-mass main-sequence companion produces a nova eruption has been understood since 1970. The mass-transferring binary stellar configuration leads inexorably to thermonuclear runaways detected at distances of megaparsecs. Summarized here are the efforts of many researchers in understanding the physical processes which generate nova eruptions; the effects upon nova eruptions of different binary-system parameters (e.g., chemical composition or mass of the white dwarf, different mass accretion rates); the possible metamorphosis from dwarf to classical novae and back again; and observational diagnostics of novae, including x ray and gamma ray emission, and the characteristics and distributions of novae in globular clusters and in extragalactic systems. While the thermonuclear-runaway model remains the successful cornerstone of nova simulation, it is now clear that a wide variety of physical processes, and three-dimensional hydrodynamic simulations, will be needed to explain the rich spectrum of behavior observed in erupting novae.

General Relativistic Simulations of Low-Mass Magnetized Binary Neutron Star Mergers

NASA Astrophysics Data System (ADS)

Giacomazzo, Bruno

2017-01-01

We will present general relativistic magnetohydrodynamic (GRMHD) simulations of binary neutron star (BNS) systems that produce long-lived neutron stars (NSs) after merger. While the standard scenario for short gamma-ray bursts (SGRBs) requires the formation after merger of a spinning black hole surrounded by an accretion disk, other theoretical models, such as the time-reversal scenario, predict the formation of a long-lived magnetar. The formation of a long-lived magnetar could in particular explain the X-ray plateaus that have been observed in some SGRBs. Moreover, observations of NSs with masses of 2 solar masses indicate that the equation of state of NS matter should support masses larger than that. Therefore a significant fraction of BNS mergers will produce long-lived NSs. This has important consequences both on the emission of gravitational wave signals and on their electromagnetic counterparts. We will discuss GRMHD simulations of ``low-mass'' magnetized BNS systems with different equations of state and mass ratios. We will describe the properties of their post-merger remnants and of their gravitational and electromagnetic emission.

Correlation between the luminosity and spin-period changes during outbursts of 12 Be binary pulsars observed by the MAXI/GSC and the Fermi/GBM

NASA Astrophysics Data System (ADS)

Sugizaki, Mutsumi; Mihara, Tatehiro; Nakajima, Motoki; Makishima, Kazuo

2017-12-01

To study observationally the spin-period changes of accreting pulsars caused by the accretion torque, the present work analyzes X-ray light curves of 12 Be binary pulsars obtained by the MAXI Gas-Slit Camera all-sky survey and their pulse periods measured by the Fermi Gamma-ray Burst Monitor pulsar project, both covering more than six years, from 2009 August to 2016 March. The 12 objects were selected because they are accompanied by clear optical identification and accurate measurements of surface magnetic fields. The luminosity L and the spin-frequency derivatives \\dot{ν}, measured during large outbursts with L ≳ 1 × 1037 erg s-1, were found to follow approximately the theoretical relations in the accretion torque models, represented by \\dot{ν} ∝ L^{α} (α ≃ 1), and the coefficient of proportionality between \\dot{ν} and Lα agrees, within a factor of ˜3, with that proposed by Ghosh and Lamb (1979b, ApJ, 234, 296). In the course of the present study, the orbital elements of several sources were refined.

A ROSAT Survey of Contact Binary Stars

NASA Astrophysics Data System (ADS)

Geske, M. T.; Gettel, S. J.; McKay, T. A.

2006-01-01

Contact binary stars are common variable stars that are all believed to emit relatively large fluxes of X-rays. In this work we combine a large new sample of contact binary stars derived from the ROTSE-I telescope with X-ray data from the ROSAT All Sky Survey (RASS) to estimate the X-ray volume emissivity of contact binary stars in the Galaxy. We obtained X-ray fluxes for 140 contact binaries from the RASS, as well as two additional stars observed by the XMM-Newton observatory. From these data we confirm the emission of X-rays from all contact binary systems, with typical luminosities of approximately 1.0×1030 ergs s-1. Combining calculated luminosities with an estimated contact binary space density, we find that contact binaries do not have strong enough X-ray emission to account for a significant portion of the Galactic X-ray background.

Hunt for infrared photons from the first binary neutron star merger

NASA Astrophysics Data System (ADS)

Kasliwal, Mansi; Growth Collaboration [Global Relay Of Observatories Watching Transients

2017-10-01

Yesterday, within two seconds of 2017 August 17 12:41:04 GMT, both LIGO interferometers and the Fermi satellite detected gravitational waves from a neutron star merger and a short contemporaneous gamma ray burst! We now have a promising optical and infrared counterpart. This may very well be a historic moment in multi-messenger astronomy, and may even prove to be of the same league as neutrinos from SN,1987A. Here, we request the Spitzer Space Telescope to engage in the hunt for infrared photons.

Search for Gravitational Waves Associated with Gamma-Ray Bursts during LIGO Science Run 6 and Virgo 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. X.; 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.; 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.; 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.; 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.; 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.; Franco, S.; 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.; Gehrels, N.; 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.; 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.; 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.; Jonker, R. J. G.; 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, P.; 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.; Malvezzi, V.; 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.; Palladino, L.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Paoletti, R.; 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.; ter Braack, A. P. M.; 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.; Tucker, 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.; LIGO Scientific Collaboration; Virgo Collaboration; Briggs, M. S.; Connaughton, V.; Hurley, K. C.; Jenke, P. A.; von Kienlin, A.; Rau, A.; Zhang, X.-L.

2012-11-01

We present the results of a search for gravitational waves associated with 154 gamma-ray bursts (GRBs) that were detected by satellite-based gamma-ray experiments in 2009-2010, during the sixth LIGO science run and the second and third Virgo science runs. We perform two distinct searches: a modeled search for coalescences of either two neutron stars or a neutron star and black hole, and a search for generic, unmodeled gravitational-wave bursts. We find no evidence for gravitational-wave counterparts, either with any individual GRB in this sample or with the population as a whole. For all GRBs we place lower bounds on the distance to the progenitor, under the optimistic assumption of a gravitational-wave emission energy of 10-2 M ⊙ c 2 at 150 Hz, with a median limit of 17 Mpc. For short-hard GRBs we place exclusion distances on binary neutron star and neutron-star-black-hole progenitors, using astrophysically motivated priors on the source parameters, with median values of 16 Mpc and 28 Mpc, respectively. These distance limits, while significantly larger than for a search that is not aided by GRB satellite observations, are not large enough to expect a coincidence with a GRB. However, projecting these exclusions to the sensitivities of Advanced LIGO and Virgo, which should begin operation in 2015, we find that the detection of gravitational waves associated with GRBs will become quite possible.

Light Curves and Spectra from a Unimodal Core-collapse Supernova

DOE PAGES

Wollaeger, Ryan T.; Hungerford, Aimee L.; Fryer, Chris L.; ...

2017-08-23

To assess the effectiveness of optical emission as a probe of spatial asymmetry in core-collapse supernovae (CCSNe), we apply in this paper the radiative transfer software SuperNu to a unimodal CCSN model. The SNSPH radiation hydrodynamics software was used to simulate an asymmetric explosion of a 16more » $${M}_{\\odot }$$ zero-age main-sequence binary star. The ejecta has 3.36 $${M}_{\\odot }$$ with 0.024 $${M}_{\\odot }$$ of radioactive 56Ni, with unipolar asymmetry along the z-axis. For 96 discrete angular views, we find a ratio between maximum and minimum peak total luminosities of ~1.36. The brightest light curves emerge from views orthogonal to the z-axis. Multigroup spectra from UV to IR are obtained. We find a shift in wavelength with viewing angle in a near-IR Ca ii emission feature, consistent with Ca being mostly in the unimode. We compare emission from the gray gamma-ray transfer in SuperNu and from the detailed gamma-ray transfer code Maverick. Relative to the optical light curves, the brightness of the gamma-ray emission is more monotonic with respect to viewing angle. UBVRI broadband light curves are also calculated. Parallel with the unimode, the U and B bands have excess luminosity at $$\\gtrsim 10$$ days post-explosion, due to 56Ni on the unimode. Finally, we compare our CCSN model with SN 2002ap, which is thought to have a similar ejecta morphology.« less

Light Curves and Spectra from a Unimodal Core-collapse Supernova

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

Wollaeger, Ryan T.; Hungerford, Aimee L.; Fryer, Chris L.

To assess the effectiveness of optical emission as a probe of spatial asymmetry in core-collapse supernovae (CCSNe), we apply in this paper the radiative transfer software SuperNu to a unimodal CCSN model. The SNSPH radiation hydrodynamics software was used to simulate an asymmetric explosion of a 16more » $${M}_{\\odot }$$ zero-age main-sequence binary star. The ejecta has 3.36 $${M}_{\\odot }$$ with 0.024 $${M}_{\\odot }$$ of radioactive 56Ni, with unipolar asymmetry along the z-axis. For 96 discrete angular views, we find a ratio between maximum and minimum peak total luminosities of ~1.36. The brightest light curves emerge from views orthogonal to the z-axis. Multigroup spectra from UV to IR are obtained. We find a shift in wavelength with viewing angle in a near-IR Ca ii emission feature, consistent with Ca being mostly in the unimode. We compare emission from the gray gamma-ray transfer in SuperNu and from the detailed gamma-ray transfer code Maverick. Relative to the optical light curves, the brightness of the gamma-ray emission is more monotonic with respect to viewing angle. UBVRI broadband light curves are also calculated. Parallel with the unimode, the U and B bands have excess luminosity at $$\\gtrsim 10$$ days post-explosion, due to 56Ni on the unimode. Finally, we compare our CCSN model with SN 2002ap, which is thought to have a similar ejecta morphology.« less

In a Flash, NASA Helps Solve 35-Year-Old Cosmic Mystery

NASA Astrophysics Data System (ADS)

2005-10-01

Scientists have solved the 35-year-old mystery of the origin of powerful, split-second flashes of light known as short gamma-ray bursts. These flashes, brighter than a billion galaxies, yet lasting only a few milliseconds, have been simply too fast to catch - until now. Through the unprecedented coordination of observations from several ground-based telescopes and NASA satellites, scientists determined the flashes arise from violent collisions in space. The clashes are either between a black hole and a neutron star or between two neutron stars. In either scenario, the impact creates a new black hole. In at least one burst, scientists saw tantalizing, first-time evidence of a black hole eating a neutron star. The neutron star was first stretched into a crescent, then swallowed by the black hole. Two recently detected bursts are featured in four papers in this week's Nature magazine. These observations could enable direct detection of exotic gravitational waves that have never before been seen. "Gamma-ray bursts in general are notoriously difficult to study, but the shortest ones have been next to impossible to pin down," said Dr. Neil Gehrels, principal investigator for the Swift satellite at NASA's Goddard Space Flight Center, Greenbelt, Md. "All that has changed. We now have the tools in place to study these events," he said. Hubble Optical Image of GRB 050709 Hubble Optical Image of GRB 050709 Gamma-ray bursts, first detected in the 1960s, are the most powerful explosions known. They are random, fleeting and can occur from any region of the sky. Two years ago, scientists discovered longer bursts, lasting more than two seconds, arise from the explosion of very massive stars. About 30 percent of bursts are short and under two seconds. The Swift satellite detected a short burst on May 9, and NASA's High-Energy Transient Explorer (HETE) detected another on July 9. The May 9 event marked the first time scientists identified an afterglow for a short gamma-ray burst, something commonly seen after long bursts. "We had a hunch that short gamma-ray bursts came from a neutron star crashing into a black hole or another neutron star, but these new detections leave no doubt," said Dr. Derek Fox, assistant professor of Astronomy & Astrophysics at Penn State University, State College, Pa. Fox is lead author of one Nature report detailing a multi-wavelength observation. Animation of Colliding Binary Neutron Stars Animation of Colliding Binary Neutron Stars Fox's team discovered the X-ray afterglow of the July 9 burst with NASA's Chandra X-ray Observatory. A team led by Jens Hjorth, a professor at the University of Copenhagen identified the optical afterglow using the Danish 1.5-meter telescope at the La Silla Observatory in Chile. Fox's team continued studying the afterglow with NASA's Hubble Space Telescope and ground-based telescopes of the Carnegie Institution, the National Astronomical Observatory of Japan, and the National Radio Astronomy Observatory. "The July 9 burst was like the dog that didn't bark," said Dr. George Ricker, HETE principal investigator at the Massachusetts Institute of Technology, Cambridge, and co-author of another Nature article. "Powerful telescopes detected no supernova as the gamma-ray burst faded, arguing against the explosion of a massive star. Also, the July 9 burst, and probably the May 9 burst, are located in the outskirts of their host galaxies, just where old merging binaries are expected," he added. Mergers create gravitational waves, ripples in space-time predicted by Einstein but never directly detected. The July 9 burst was about 2 billion light-years away. A big merger closer to the Earth could be detected by the National Science Foundation's Laser Interferometer Gravitational-Wave Observatory (LIGO). If Swift detects a nearby short burst, scientists could go back and check the data with a precise time and location. "This is good news for LIGO," said Dr. Albert Lazzarini, Data & Computing group leader at the California Institute of Technology LIGO Lab, Pasadena. "The connection between short bursts and mergers firms up projected rates for LIGO, and they appear to be at the high end of previous estimates. Also, observations provide tantalizing hints of black hole-neutron star mergers, which have not been detected before," he said. For information about this discovery, visit: For information about this discovery, visit: http://www.nasa.gov/mission_pages/swift/bursts/short_burst_oct5.html For information about NASA and agency programs on the Web, visit: http://www.nasa.gov/home/index.html

Fe-catalyzed thermal conversion of sodium lignosulfonate to graphene

Treesearch

Sung Phil Mun; Zhiyong Cai; Jilei Zhang

2013-01-01

Sodium lignosulfonate (LS) from sulfite pulping processing was used as a carbon source to synthesize graphene. LS was mixed with Fe nanoparticles (FeNPs) as a catalyst and thermally treated at 1000 °C for 1 h. The Raman spectrum and X-ray diffraction pattern suggested that graphene sheets were formed in LS thermally treated with FeNPs (Fe-HTLS). Scanning...

Binary neutron star mergers: a review of Einstein's richest laboratory.

PubMed

Baiotti, Luca; Rezzolla, Luciano

2017-09-01

In a single process, the merger of binary neutron star systems combines extreme gravity, the copious emission of gravitational waves, complex microphysics and electromagnetic processes, which can lead to astrophysical signatures observable at the largest redshifts. We review here the recent progress in understanding what could be considered Einstein's richest laboratory, highlighting in particular the numerous significant advances of the last decade. Although special attention is paid to the status of models, techniques and results for fully general-relativistic dynamical simulations, a review is also offered on the initial data and advanced simulations with approximate treatments of gravity. Finally, we review the considerable amount of work carried out on the post-merger phase, including black-hole formation, torus accretion onto the merged compact object, the connection with gamma-ray burst engines, ejected material, and its nucleosynthesis.

Binary neutron star mergers: a review of Einstein’s richest laboratory

NASA Astrophysics Data System (ADS)

Baiotti, Luca; Rezzolla, Luciano

2017-09-01

In a single process, the merger of binary neutron star systems combines extreme gravity, the copious emission of gravitational waves, complex microphysics and electromagnetic processes, which can lead to astrophysical signatures observable at the largest redshifts. We review here the recent progress in understanding what could be considered Einstein’s richest laboratory, highlighting in particular the numerous significant advances of the last decade. Although special attention is paid to the status of models, techniques and results for fully general-relativistic dynamical simulations, a review is also offered on the initial data and advanced simulations with approximate treatments of gravity. Finally, we review the considerable amount of work carried out on the post-merger phase, including black-hole formation, torus accretion onto the merged compact object, the connection with gamma-ray burst engines, ejected material, and its nucleosynthesis.

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.

Single progenitor model for GW150914 and GW170104

NASA Astrophysics Data System (ADS)

D'Orazio, Daniel J.; Loeb, Abraham

2018-04-01

The merger of stellar-mass black holes (BHs) is not expected to generate detectable electromagnetic (EM) emission. However, the gravitational wave (GW) events GW150914 and GW170104, detected by the Laser Interferometer Gravitational Wave Observatory to be the result of merging, ˜60 M⊙ binary black holes (BBHs), each have claimed coincident gamma-ray emission. Motivated by the intriguing possibility of an EM counterpart to BBH mergers, we construct a model that can reproduce the observed EM and GW signals for GW150914- and GW170104-like events, from a single-star progenitor. Following Loeb [Astrophys. J. Lett. 819, L21 (2016), 10.3847/2041-8205/819/2/L21], we envision a massive, rapidly rotating star within which a rotating-bar instability fractures the core into two overdensities that fragment into clumps which merge to form BHs in a tight binary with arbitrary spin-orbit alignment. Once formed, the BBH inspirals due to gas and gravitational-wave drag until tidal forces trigger strong feeding of the BHs with the surrounding stellar-density gas about 10 sec before merger. The resulting giga-Eddington accretion peak launches a jet that breaks out of the progenitor star and drives a powerful outflow that clears the gas from the orbit of the binary within 1 sec, preserving the vacuum GW waveform in the Laser Interferometer Gravitational Wave Observatory band. The single-progenitor scenario predicts the existence of variability of the gamma-ray burst, modulated at the ˜0.2 sec chirping period of the BBH due to relativistic Doppler boost. The jet breakout should be accompanied by a low-luminosity supernova. Finally, because the BBHs of the single-progenitor model do not exist at large separations, they will not be detectable in the low-frequency gravitational-wave band of the Laser Interferometer Space Antenna. Hence, the single-progenitor BBHs will be unambiguously discernible from BBHs formed through alternate, double-progenitor evolution scenarios.

THE LOCATIONS OF SHORT GAMMA-RAY BURSTS AS EVIDENCE FOR COMPACT OBJECT BINARY PROGENITORS

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

Fong, W.; Berger, E.

2013-10-10

We present a detailed investigation of Hubble Space Telescope rest-frame UV/optical observations of 22 short gamma-ray burst (GRB) host galaxies and sub-galactic environments. Utilizing the high angular resolution and depth of HST we characterize the host galaxy morphologies, measure precise projected physical and host-normalized offsets between the bursts and host centers, and calculate the locations of the bursts with respect to their host light distributions (rest-frame UV and optical). We calculate a median short GRB projected physical offset of 4.5 kpc, about 3.5 times larger than that for long GRBs, and find that ≈25% of short GRBs have offsets ofmore » ∼> 10 kpc. When compared to their host sizes, the median offset is 1.5 half-light radii (r{sub e} ), about 1.5 times larger than the values for long GRBs, core-collapse supernovae, and Type Ia supernovae. In addition, ≈20% of short GRBs having offsets of ∼> 5r{sub e} , and only ≈25% are located within 1r{sub e} . We further find that short GRBs severely under-represent their hosts' rest-frame optical and UV light, with ≈30%-45% of the bursts located in regions of their host galaxies that have no detectable stellar light, and ≈55% in the regions with no UV light. Therefore, short GRBs do not occur in regions of star formation or even stellar mass. This demonstrates that the progenitor systems of short GRBs must migrate from their birth sites to their eventual explosion sites, a signature of kicks in compact object binary systems. Utilizing the full sample of offsets, we estimate natal kick velocities of ≈20-140 km s{sup –1}. These independent lines of evidence provide the strongest support to date that short GRBs result from the merger of compact object binaries (NS-NS/NS-BH)« less

Neutron-star–black-hole binaries produced by binary-driven hypernovae

DOE PAGES

Fryer, Chris L.; Oliveira, F. G.; Rueda, Jorge A.; ...

2015-12-04

Here, binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (E iso ≳10 52 erg), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed “ultrastripped” binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differentlymore » than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs.« less

Neutron-Star-Black-Hole Binaries Produced by Binary-Driven Hypernovae.

PubMed

Fryer, Chris L; Oliveira, F G; Rueda, J A; Ruffini, R

2015-12-04

Binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (E_{iso}≳10^{52}  erg), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed "ultrastripped" binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs.

Neutron-Star-Black-Hole Binaries Produced by Binary-Driven Hypernovae

NASA Astrophysics Data System (ADS)

Fryer, Chris L.; Oliveira, F. G.; Rueda, J. A.; Ruffini, R.

2015-12-01

Binary-driven hypernovae (BdHNe) within the induced gravitational collapse paradigm have been introduced to explain energetic (Eiso≳1052 erg ), long gamma-ray bursts (GRBs) associated with type Ic supernovae (SNe). The progenitor is a tight binary composed of a carbon-oxygen (CO) core and a neutron-star (NS) companion, a subclass of the newly proposed "ultrastripped" binaries. The CO-NS short-period orbit causes the NS to accrete appreciable matter from the SN ejecta when the CO core collapses, ultimately causing it to collapse to a black hole (BH) and producing a GRB. These tight binaries evolve through the SN explosion very differently than compact binaries studied in population synthesis calculations. First, the hypercritical accretion onto the NS companion alters both the mass and the momentum of the binary. Second, because the explosion time scale is on par with the orbital period, the mass ejection cannot be assumed to be instantaneous. This dramatically affects the post-SN fate of the binary. Finally, the bow shock created as the accreting NS plows through the SN ejecta transfers angular momentum, braking the orbit. These systems remain bound even if a large fraction of the binary mass is lost in the explosion (well above the canonical 50% limit), and even large kicks are unlikely to unbind the system. Indeed, BdHNe produce a new family of NS-BH binaries unaccounted for in current population synthesis analyses and, although they may be rare, the fact that nearly 100% remain bound implies that they may play an important role in the compact merger rate, important for gravitational waves that, in turn, can produce a new class of ultrashort GRBs.

Identification of the Hard X-Ray Source Dominating the E > 25 keV Emission of the Nearby Galaxy M31

NASA Technical Reports Server (NTRS)

Yukita, M.; Ptak, A.; Hornschemeier, A. E.; Wik, D.; Maccarone, T.J.; Pottschmidt, Katja; Zezas, A.; Antoniou, V.; Ballhausen, R.; Lehmer, B.D.;

A Deep X-ray Survey of the Globular Cluster Omega Centauri

NASA Astrophysics Data System (ADS)

Henleywillis, Simon; Cool, Adrienne M.; Haggard, Daryl; Heinke, Craig; Callanan, Paul; Zhao, Yue

2018-03-01

We identify 233 X-ray sources, of which 95 are new, in a 222 ks exposure of Omega Centauri with the Chandra X-ray Observatory's ACIS-I detector. The limiting unabsorbed flux in the core is fX(0.5-6.0 keV) ≃ 3×10-16 erg s-1 cm-2 (Lx ≃ 1×1030 erg s-1 at 5.2 kpc). We estimate that ˜60 ± 20 of these are cluster members, of which ˜30 lie within the core (rc = 155 arcsec), and another ˜30 between 1-2 core radii. We identify four new optical counterparts, for a total of 45 likely identifications. Probable cluster members include 18 cataclysmic variables (CVs) and CV candidates, one quiescent low-mass X-ray binary, four variable stars, and five stars that are either associated with ω Cen's anomalous red giant branch, or are sub-subgiants. We estimate that the cluster contains 40 ± 10 CVs with Lx > 1031 erg s-1, confirming that CVs are underabundant in ω Cen relative to the field. Intrinsic absorption is required to fit X-ray spectra of six of the nine brightest CVs, suggesting magnetic CVs, or high-inclination systems. Though no radio millisecond pulsars (MSPs) are currently known in ω Cen, more than 30 unidentified sources have luminosities and X-ray colours like those of MSPs found in other globular clusters; these could be responsible for the Fermi-detected gamma-ray emission from the cluster. Finally, we identify a CH star as the counterpart to the second-brightest X-ray source in the cluster and argue that it is a symbiotic star. This is the first such giant/white dwarf binary to be identified in a globular cluster.

Identification of the Hard X-Ray Source Dominating the E > 25 keV Emission of the Nearby Galaxy M31

NASA Technical Reports Server (NTRS)

Yukita, M.; Ptak, A.; Hornschemeier, A. E.; Wik, D.; Maccarone, T. J.; Pottschmidt, K.; Zezas, A.; Antoniou, V.; Ballhausen, R.; Lehmer, B. D.;

FERMI GBM OBSERVATIONS OF V404 CYG DURING ITS 2015 OUTBURST

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

Jenke, P. A.; Veres, P.; Briggs, M. S.

2016-07-20

V404 Cygni was discovered in 1989 by the Ginga X-ray satellite during its only previously observed X-ray outburst and soon after confirmed as a black hole binary. On 2015 June 15, the Gamma-ray Burst Monitor (GBM) triggered on a new outburst of V404 Cygni. We present 13 days of GBM observations of this outburst, including Earth occultation flux measurements and spectral and temporal analysis. The Earth occultation fluxes reached 30 Crab with detected emission to 100 keV and determined, via hardness ratios, that the source was in a hard state. At high luminosity, spectral analysis between 8 and 300 keVmore » showed that the electron temperature decreased with increasing luminosity. This is expected if the protons and electrons are in thermal equilibrium during an outburst with the electrons cooled by the Compton scattering of softer seed photons from the disk. However, the implied seed photon temperatures are unusually high, suggesting a contribution from another source, such as the jet. No evidence of state transitions is seen during this time period. The temporal analysis reveals power spectra that can be modeled with two or three strong, broad Lorentzians, similar to the power spectra of black hole binaries in their hard state.« less

A deep survey of the X-ray binary populations in the SMC

NASA Astrophysics Data System (ADS)

Zezas, A.; Antoniou, V.

2017-10-01

The Small Magellanic Cloud (SMC) has been the subject of systematic X-ray surveys over the past two decades, which have yielded a rich population of high-mass X-ray binaries consisting predominantly of Be/X-ray binaries. We present results from our deep Chandra survey of the SMC which targeted regions with stellar populations ranging between ˜10-100 Myr. X-ray luminosities down to ˜3×10^{32} erg/s were reached, probing all active accreting binaries and extending well into the regime of quiescent accreting binaries and X-ray emitting normal stars. We measure the dependence of the formation efficiency of X-ray binaries on age. We also detect pulsations from 19 known and one new candidate pulsar. We construct the X-ray luminosity function in different regions of the SMC, which shows clear evidence for the propeller effect the centrifugal inhibition of accretion due to the interaction of the accretion flow with the pulsar's magnetic field. Finally we compare these results with predictions for the formation efficiency of X-ray binaries as a function of age from X-ray binary population synthesis models.

Multiwavelength Observations of the Redback Millisecond Pulsar J1048+2339

DOE PAGES

Deneva, J. S.; Ray, P. S.; Camilo, F.; ...

2016-05-26

In this paper, we report on radio timing and multiwavelength observations of the 4.66 ms redback pulsar J1048+2339, which was discovered in an Arecibo search targeting the Fermi-Large Area Telescope source 3FGL J1048.6+2338. Two years of timing allowed us to derive precise astrometric and orbital parameters for the pulsar. PSR J1048+2339 is in a 6 hr binary and exhibits radio eclipses over half the orbital period and rapid orbital period variations. The companion has a minimum mass of 0.3 M ⊙, and we have identified a V ~ 20 variable optical counterpart in data from several surveys. The phasing ofmore » its ~1 mag modulation at the orbital period suggests highly efficient and asymmetric heating by the pulsar wind, which may be due to an intrabinary shock that is distorted near the companion, or to the companion's magnetic field channeling the pulsar wind to specific locations on its surface. Finally, we also present gamma-ray spectral analysis of the source and preliminary results from searches for gamma-ray pulsations using the radio ephemeris.« less

Prompt emission from the counter jet of a short gamma-ray burst

NASA Astrophysics Data System (ADS)

Yamazaki, Ryo; Ioka, Kunihito; Nakamura, Takashi

2018-03-01

The counter jet of a short gamma-ray burst (sGRB) has not yet been observed, while recent discoveries of gravitational waves (GWs) from a binary neutron star merger GW170817 and the associated sGRB 170817A have demonstrated that off-axis sGRB jets are detectable. We calculate the prompt emission from the counter jet of an sGRB and show that it is typically 23-26 mag in the optical-infrared band 10-10^3 s after the GWs for an sGRB 170817A-like event, which is brighter than the early macronova (or kilonova) emission and detectable by LSST in the near future. We also propose a new method to constrain the unknown jet properties, such as the Lorentz factor, opening angle, emission radii, and jet launch time, by observing both the forward and counter jets. To scrutinize the counter jets, space GW detectors like DECIGO are powerful in forecasting the merger time (≲ 1 s) and position (≲ 1 arcmin) (˜ a week) before the merger.

Implications for the Origin of GRB 051103 from LIGO Observations

NASA Astrophysics Data System (ADS)

Abadie, J.; Abbott, B. P.; Abbott, T. D.; Abbott, R.; Abernathy, M.; Adams, C.; Adhikari, R.; Affeldt, C.; 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.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P.; Ballmer, S.; Barker, D.; Barnum, S.; Barr, B.; Barriga, P.; Barsotti, L.; Barton, M. A.; Bartos, I.; Bassiri, R.; Bastarrika, M.; Bauchrowitz, J.; Behnke, B.; Bell, A. S.; Belopolski, I.; Benacquista, M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biswas, R.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Bock, O.; Bodiya, T. P.; Bogan, C.; Bondarescu, R.; Bork, R.; Born, M.; Bose, S.; Boyle, M.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Breyer, J.; Bridges, D. O.; Brinkmann, M.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Brummitt, A.; Buonanno, A.; Burguet-Castell, J.; Burmeister, O.; Byer, R. L.; Cadonati, L.; Camp, J. B.; Campsie, P.; Cannizzo, J.; Cannon, K.; Cao, J.; Capano, C.; Caride, S.; Caudill, S.; Cavaglia, M.; Cepeda, C.; Chalermsongsak, T.; Chalkley, E.; Charlton, P.; Chelkowski, S.; Chen, Y.; Christensen, N.; Chua, S. S. Y.; Chung, S.; Chung, C. T. Y.; Clara, F.; Clark, D.; Clark, J.; Clayton, J. H.; Conte, R.; Cook, D.; Corbitt, T. R. C.; Cornish, N.; Costa, C. A.; Coughlin, M.; Coward, D. M.; Coyne, D. C.; Creighton, J. D. E.; Creighton, T. D.; Cruise, A. M.; Cumming, A.; Cunningham, L.; Culter, R. M.; Dahl, K.; Danilishin, S. L.; Dannenberg, R.; Danzmann, K.; Das, K.; Daudert, B.; Daveloza, H.; Davies, G.; Daw, E. J.; Dayanga, T.; DeBra, D.; Degallaix, J.; Dent, T.; Dergachev, V.; DeRosa, R.; DeSalvo, R.; Dhurandhar, S.; Di Palma, I.; Díaz, M.; Donovan, F.; Dooley, K. L.; Dorsher, S.; Douglas, E. S. D.; Drever, R. W. P.; Driggers, J. C.; Dumas, J.-C.; Dwyer, S.; Eberle, T.; Edgar, M.; Edwards, M.; Effler, A.; Ehrens, P.; Engel, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fairhurst, S.; Fan, Y.; Farr, B. F.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Finn, L. S.; Flanigan, M.; Foley, S.; Forsi, E.; Fotopoulos, N.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Friedrich, D.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Garcia, J.; Garofoli, J. A.; Gholami, I.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Gill, C.; Goetz, E.; Goggin, L. M.; González, G.; Gorodetsky, M. L.; Goßler, S.; Graef, C.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Grosso, R.; Grote, H.; Grunewald, S.; Guido, C.; Gupta, R.; Gustafson, E. K.; Gustafson, R.; Hage, B.; 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.; Heefner, J.; 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.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kanner, J. B.; Katsavounidis, E.; Katzman, W.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kells, W.; Kelner, M.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, N.; Kim, H.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kondrashov, V.; Kopparapu, R.; Koranda, S.; Korth, W. Z.; Kozak, D.; Kringel, V.; Krishnamurthy, S.; Krishnan, B.; Kuehn, G.; Kumar, R.; Kwee, P.; Landry, M.; Lantz, B.; Lastzka, N.; Lazzarini, A.; Leaci, P.; Leong, J.; Leonor, I.; Li, J.; Lindquist, P. E.; Lockerbie, N. A.; Lodhia, D.; Lormand, M.; Lu, P.; Luan, J.; Lubinski, M.; Lück, H.; Lundgren, A. P.; Macdonald, E.; Machenschalk, B.; MacInnis, M.; Mageswaran, M.; Mailand, K.; Mandel, I.; Mandic, V.; Marandi, A.; Márka, S.; Márka, Z.; Maros, E.; Martin, I. W.; Martin, R. M.; Marx, J. N.; Mason, K.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; McKechan, D. J. A.; Meadors, G.; Mehmet, M.; Meier, T.; Melatos, A.; Melissinos, A. C.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Miller, J.; Mino, Y.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Miyakawa, O.; Moe, B.; Moesta, P.; Mohanty, S. D.; Moraru, D.; Moreno, G.; Mossavi, K.; Mow-Lowry, C. M.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Müller-Ebhardt, H.; Munch, J.; Murphy, D.; Murray, P. G.; Nash, T.; Nawrodt, R.; Nelson, J.; Newton, G.; Nishizawa, A.; Nolting, D.; Nuttall, L.; O'Reilly, B.; O'Shaughnessy, R.; Ochsner, E.; O'Dell, J.; Ogin, G. H.; Oldenburg, R. G.; Osthelder, C.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Page, A.; Pan, Y.; Pankow, C.; Papa, M. A.; Patel, P.; Pedraza, M.; Pekowsky, L.; Penn, S.; Peralta, C.; Perreca, A.; Phelps, M.; Pickenpack, M.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Plissi, M. V.; Podkaminer, J.; Pöld, J.; Postiglione, F.; Predoi, V.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prokhorov, L.; Puncken, O.; Quetschke, V.; Raab, F. J.; Radkins, H.; Raffai, P.; Rakhmanov, M.; Ramet, C. R.; Rankins, B.; Mohapatra, S. R. P.; Raymond, V.; Redwine, K.; Reed, C. M.; Reed, T.; Reid, S.; Reitze, D. H.; Riesen, R.; Riles, K.; Roberts, P.; Robertson, N. A.; Robinson, C.; Robinson, E. L.; Roddy, S.; Rollins, J.; Romano, J. D.; Romie, J. H.; Röver, C.; Rowan, S.; Rüdiger, A.; Ryan, K.; Sakata, S.; Sakosky, M.; Salemi, F.; Salit, M.; Sammut, L.; Sancho de la Jordana, L.; Sandberg, V.; Sannibale, V.; Santamaría, L.; Santiago-Prieto, I.; Santostasi, G.; Saraf, S.; Sathyaprakash, B. S.; Sato, S.; Saulson, P. R.; Savage, R.; 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.; Sergeev, A.; Shaddock, D. A.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shihan Weerathunga, T.; 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, R.; Smith, J. R.; Smith, M. R.; Smith, N. D.; Somiya, K.; Sorazu, B.; Soto, J.; Speirits, F. C.; Stein, A. J.; Steinlechner, J.; Steinlechner, S.; Steplewski, S.; Stefszky, M.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S.; Stroeer, A. S.; Stuver, A. L.; Summerscales, T. Z.; Sung, M.; Susmithan, S.; Sutton, P. J.; Szokoly, G. P.; 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.; Torres, C.; Torrie, C. I.; Traylor, G.; Trias, M.; Tseng, K.; Ugolini, D.; Urbanek, K.; Vahlbruch, H.; Vaishnav, B.; Vallisneri, M.; Van Den Broeck, C.; van der Sluys, M. V.; van Veggel, A. A.; Vass, S.; Vaulin, R.; Vecchio, A.; Veitch, J.; Veitch, P. J.; Veltkamp, C.; Villar, A. E.; Vorvick, C.; Vyachanin, S. P.; Waldman, S. J.; Wallace, L.; Wanner, A.; Ward, R. L.; 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.; Woan, G.; Wooley, R.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, K.; Yamamoto, H.; Yang, H.; Yeaton-Massey, D.; Yoshida, S.; Yu, P.; Zanolin, M.; Zhang, L.; Zhang, Z.; Zhao, C.; Zotov, N.; Zucker, M. E.; Zweizig, J.; LIGO Collaboration; Bizouard, M. A.; Dietz, A.; Guidi, G. M.; Was, M.

2012-08-01

We present the results of a LIGO search for gravitational waves (GWs) associated with GRB 051103, a short-duration hard-spectrum gamma-ray burst (GRB) whose electromagnetically determined sky position is coincident with the spiral galaxy M81, which is 3.6 Mpc from Earth. Possible progenitors for short-hard GRBs include compact object mergers and soft gamma repeater (SGR) giant flares. A merger progenitor would produce a characteristic GW signal that should be detectable at a distance of M81, while GW emission from an SGR is not expected to be detectable at that distance. We found no evidence of a GW signal associated with GRB 051103. Assuming weakly beamed γ-ray emission with a jet semi-angle of 30°, we exclude a binary neutron star merger in M81 as the progenitor with a confidence of 98%. Neutron star-black hole mergers are excluded with >99% confidence. If the event occurred in M81, then our findings support the hypothesis that GRB 051103 was due to an SGR giant flare, making it one of the most distant extragalactic magnetars observed to date.

The Fate of the Compact Remnant in Neutron Star Mergers

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

Fryer, Chris L.; Belczynski, Krzysztoff; Ramirez-Ruiz, Enrico

Neutron star (binary neutron star and neutron star - black hole) mergers are believed to produce short-duration gamma-ray bursts. They are also believed to be the dominant source of gravitational waves to be detected by the advanced LIGO and the dominant source of the heavy r-process elements in the universe. Whether or not these mergers produce short-duration GRBs depends sensitively on the fate of the core of the remnant (whether, and how quickly, it forms a black hole). In this paper, we combine the results of merger calculations and equation of state studies to determine the fate of the coresmore » of neutron star mergers. Using population studies, we can determine the distribution of these fates to compare to observations. We find that black hole cores form quickly only for equations of state that predict maximum non-rotating neutron star masses below 2.3-2.4 solar masses. If quick black hole formation is essential in producing gamma-ray bursts, LIGO observed rates compared to GRB rates could be used to constrain the equation of state for dense nuclear matter.« less

SWIFT Detects a remarkable Gamma-ray Burst, GRB 060514, that introduces a New Classification Scheme

NASA Technical Reports Server (NTRS)

Gehrels, N.; Norris, J. P.; Mangano, V.; Barthelmy, S. D.; Burrows, D. N.; Granot, J.; Kaneko, Y.; Kouveliotou, C.; Markwardt, C. B.; Meszaros, P.;

The Fate of the Compact Remnant in Neutron Star Mergers

DOE PAGES

Fryer, Chris L.; Belczynski, Krzysztoff; Ramirez-Ruiz, Enrico; ...

2015-10-06

Neutron star (binary neutron star and neutron star - black hole) mergers are believed to produce short-duration gamma-ray bursts. They are also believed to be the dominant source of gravitational waves to be detected by the advanced LIGO and the dominant source of the heavy r-process elements in the universe. Whether or not these mergers produce short-duration GRBs depends sensitively on the fate of the core of the remnant (whether, and how quickly, it forms a black hole). In this paper, we combine the results of merger calculations and equation of state studies to determine the fate of the coresmore » of neutron star mergers. Using population studies, we can determine the distribution of these fates to compare to observations. We find that black hole cores form quickly only for equations of state that predict maximum non-rotating neutron star masses below 2.3-2.4 solar masses. If quick black hole formation is essential in producing gamma-ray bursts, LIGO observed rates compared to GRB rates could be used to constrain the equation of state for dense nuclear matter.« less

New Evidence for a Black Hole in the Compact Binary Cygnus X-3

NASA Technical Reports Server (NTRS)

Shrader, Chris R.; Titarchuk, Lev; Shaposhnikov, Nikolai

2010-01-01

The bright and highly variable X-ray and radio source known as Cygnus X-3 was among the first X-ray sources discovered, yet it remains in many ways an enigma. Its known to consist of a massive. Wolf-Rayet primary in an extremely tight orbit with a compact object. Yet one of the most basic of pa.ranietern the mass of the compact object - is not known. Nor is it even clear whether its is a neutron star or a black hole. In this Paper we present our analysis of the broad-band high-energy continua covering a substantial range in luminosity and spectral morphology. We apply these results to a recently identified scaling relationship which has been demonstrated to provide reliable estimates of the compact object mass in a number of accretion powered binaries. This analysis leads us to conclude that the compact object in Cygnus X-3 has a mass greater than 4.2 solar mass thus clearly indicative of a black hole and as such resolving a longstanding issue. The full range of uncertainty in our analysis and from using a. range of recently published distance estimates constrains the compact object mass to lie between 4.2 solar mass and 14.4 solar mass. Our favored estimate, based on a 9.0 kpc distance estimate is approx. l0 solar mass, with the. error margin of 3.2 solar masses. This result may thus pose challenges to shared-envelope evolutionary models of compact binaries. as well as establishing Cygnus X-3 as the first confirmed accretion-powered galactic gamma: ray source.

A year-long AGILE observation of Cygnus X-1 in hard spectral state

NASA Astrophysics Data System (ADS)

Del Monte, E.; Feroci, M.; Evangelista, Y.; Costa, E.; Donnarumma, I.; Lapshov, I.; Lazzarotto, F.; Pacciani, L.; Rapisarda, M.; Soffitta, P.; Argan, A.; Barbiellini, G.; Boffelli, F.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P. W.; Chen, A.; D'Ammando, F.; Di Cocco, G.; Fuschino, F.; Galli, M.; Gianotti, F.; Giuliani, A.; Labanti, C.; Lipari, P.; Longo, F.; Marisaldi, M.; Mereghetti, S.; Moretti, E.; Morselli, A.; Pellizzoni, A.; Perotti, F.; Piano, G.; Picozza, P.; Pilia, M.; Prest, M.; Pucella, G.; Rappoldi, A.; Sabatini, S.; Striani, E.; Tavani, M.; Trifoglio, M.; Trois, A.; Vallazza, E.; Vercellone, S.; Vittorini, V.; Zambra, A.; Antonelli, L. A.; Cutini, S.; Pittori, C.; Preger, B.; Santolamazza, P.; Verrecchia, F.; Giommi, P.; Salotti, L.

2010-09-01

Context. Cygnus X-1 (Cyg X-1) is a high mass X-ray binary system, known to be a black hole candidate and one of the brightest sources in the X-ray sky, which shows both variability on all timescales and frequent flares. The source spends most of the time in a hard spectral state, dominated by a power-law emission, with occasional transitions to the soft and intermediate states, where a strong blackbody component emerges. Aims: We present the observation of Cyg X-1 in a hard spectral state performed during the AGILE science verification phase and observing cycle 1 in hard X-rays (with SuperAGILE) and gamma rays (with the gamma ray imaging detector) and lasting for about 160 days with a live time of ~6 Ms. Methods: We investigated the variability of Cyg X-1 in hard X-rays on different timescales, from ~300 s up to one day, and we applied different tools of timing analysis, such as the autocorrelation function, the first-order structure function, and the Lomb-Scargle periodogram, to our data (from SuperAGILE) and to the simultaneous data in soft X-rays (from RXTE/ASM). We concluded our investigation with a search for emission in the energy range above 100 MeV with the maximum likelihood technique. Results: In the hard X-ray band, the flux of Cyg X-1 shows its typical erratic fluctuations on all timescales with variations of about a factor of two that do not significantly affect the shape of the energy spectrum. From the first-order structure function, we find that the X-ray emission of Cyg X-1 is characterized by antipersistence (anticorrelation in the time series, with an increase in the emission likely followed by a decrease), indicative of a negative feedback mechanism at work. In the gamma ray data a statistically significant point-like source at the position of Cyg X-1 is not found, and the upper limit on the flux is 5 × 10-8 ph cm-2 s-1 over the whole observation (160 days). Finally we compared our upper limit in gamma rays with the expectation of various models of the Cyg X-1 emission, both of hadronic and leptonic origin, in the GeV-TeV band. Conclusions: The time history of Cyg X-1 in the hard X-ray band over 13 months (not continuous) is shown. Different analysis tools do not provide fully converging results of the characteristic timescales in the system, suggesting that the timescales found in the structure function are not intrinsic to the physics of the source. While Cyg X-1 is not detected in gamma rays, our upper limit is a factor of two lower than the EGRET one and is compatible with the extrapolation of the flux measured by COMPTEL in the same spectral state.

Association with replication between estrogen-related receptor gamma (ESRRgamma) polymorphisms and bone phenotypes in women of European ancestry.

PubMed

Elfassihi, Latifa; Giroux, Sylvie; Bureau, Alexandre; Laflamme, Nathalie; Cole, David Ec; Rousseau, François

2010-04-01

Osteoporosis is a bone disease characterized by low bone mineral density (BMD), a highly heritable polygenic trait. Women are more prone than men to develop osteoporosis owing to a lower peak bone mass and accelerated bone loss at menopause. Lack of estrogen thus is a major risk factor for osteoporosis. In addition to having strong similarity to the estrogen receptor 1 (ESR1), the orphan nuclear estrogen-related receptor gamma (ESRRgamma) is widely expressed and shows overlap with ESR1 expression in tissues where estrogen has important physiologic functions. For these reasons, we have undertaken a study of ESRRgamma sequence variants in association with bone measurements [heel quantitative ultrasound (QUS) by measurements of broadband ultrasound attenuation (BUA), speed of sound (SOS), and stiffness index (SI) and dual-energy X-ray absorptiometry (DXA) at the femoral neck (FN) and lumbar spine (LS)]. A silent variant was found to be associated with multiple bone measurements (LS, BUA, SOS, and SI), the p values ranging from .006 to .04 in a sample of 5144 Quebec women. The region of this variant was analyzed using the HapMap database and the Gabriel method to define a block of 20 kb. Using the Tagger method, eight TagSNPs were identified and genotyped in a sample of 1335 women. Four of these SNPs capture the five major block haplotypes. One SNP (rs2818964) and one haplotype were significantly associated with multiple bone measures. All SNPs involved in the associations were analyzed in two other sample sets with significant results in the same direction. These results suggest involvement of ESRRgamma in the determination of bone density in women. Copyright 2010 American Society for Bone and Mineral Research.

The Advanced Gamma-ray Imaging System (AGIS)-Science Highlights

NASA Astrophysics Data System (ADS)

Buckley, J.; Coppi, P.; Digel, S.; Funk, S.; Krawczynski, H.; Krennrich, F.; Pohl, M.; Romani, R.; Vassiliev, V.

2008-12-01

The Advanced Gamma-ray Imaging System (AGIS), a future gamma-ray telescope consisting of an array of ~50 atmospheric Cherenkov telescopes distributed over an area of ~1 km2, will provide a powerful new tool for exploring the high-energy universe. The order-of-magnitude increase in sensitivity and improved angular resolution could provide the first detailed images of γ-ray emission from other nearby galaxies or galaxy clusters. The large effective area will provide unprecedented sensitivity to short transients (such as flares from AGNs and GRBs) probing both intrinsic spectral variability (revealing the details of the acceleration mechanism and geometry) as well as constraining the high-energy dispersion in the velocity of light (probing the structure of spacetime and Lorentz invariance). A wide field of view (~4 times that of current instruments) and excellent angular resolution (several times better than current instruments) will allow for an unprecedented survey of the Galactic plane, providing a deep unobscured survey of SNRs, X-ray binaries, pulsar-wind nebulae, molecular cloud complexes and other sources. The differential flux sensitivity of ~10-13 erg cm-2 sec-1 will rival the most sensitive X-ray instruments for these extended Galactic sources. The excellent capabilities of AGIS at energies below 100 GeV will provide sensitivity to AGN and GRBs out to cosmological redshifts, increasing the number of AGNs detected at high energies from about 20 to more than 100, permitting population studies that will provide valuable insights into both a unified model for AGN and a detailed measurement of the effects of intergalactic absorption from the diffuse extragalactic background light. A new instrument with fast-slewing wide-field telescopes could provide detections of a number of long-duration GRBs providing important physical constraints from this new spectral component. The new array will also have excellent background rejection and very large effective area, providing the very high sensitivity needed to detect emission from dark matter annihilation in Galactic substructure or nearby Dwarf spheroidal galaxies.

Basics of Gamma Ray Detection

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

Stinnett, Jacob; Venkataraman, Ram

The objective of this training is to explain the origin of x-rays and gamma rays, gamma ray interactions with matter, detectors and electronics used in gamma ray-spectrometry, and features of a gamma-ray spectrum for nuclear material that is safeguarded.

Nucleosynthesis in Supernovae

NASA Astrophysics Data System (ADS)

Thielemann, Friedrich-Karl; Isern, Jordi; Perego, Albino; von Ballmoos, Peter

2018-04-01

We present the status and open problems of nucleosynthesis in supernova explosions of both types, responsible for the production of the intermediate mass, Fe-group and heavier elements (with the exception of the main s-process). Constraints from observations can be provided through individual supernovae (SNe) or their remnants (e.g. via spectra and gamma-rays of decaying unstable isotopes) and through surface abundances of stars which witness the composition of the interstellar gas at their formation. With a changing fraction of elements heavier than He in these stars (known as metallicity) the evolution of the nucleosynthesis in galaxies over time can be determined. A complementary way, related to gamma-rays from radioactive decays, is the observation of positrons released in β+-decays, as e.g. from ^{26}Al, ^{44}Ti, ^{56,57}Ni and possibly further isotopes of their decay chains (in competition with the production of e+e- pairs in acceleration shocks from SN remnants, pulsars, magnetars or even of particle physics origin). We discuss (a) the role of the core-collapse supernova explosion mechanism for the composition of intermediate mass, Fe-group (and heavier?) ejecta, (b) the transition from neutron stars to black holes as the final result of the collapse of massive stars, and the relation of the latter to supernovae, faint supernovae, and gamma-ray bursts/hypernovae, (c) Type Ia supernovae and their nucleosynthesis (e.g. addressing the ^{55}Mn puzzle), plus (d) further constraints from galactic evolution, γ-ray and positron observations. This is complemented by the role of rare magneto-rotational supernovae (related to magnetars) in comparison with the nucleosynthesis of compact binary mergers, especially with respect to forming the heaviest r-process elements in galactic evolution.

Formation and Evolution of X-ray Binaries

NASA Astrophysics Data System (ADS)

Fragkos, Anastasios

X-ray binaries - mass-transferring binary stellar systems with compact object accretors - are unique astrophysical laboratories. They carry information about many complex physical processes such as star formation, compact object formation, and evolution of interacting binaries. My thesis work involves the study of the formation and evolution of Galactic and extra-galacticX-ray binaries using both detailed and realistic simulation tools, and population synthesis techniques. I applied an innovative analysis method that allows the reconstruction of the full evolutionary history of known black hole X-ray binaries back to the time of compact object formation. This analysis takes into account all the available observationally determined properties of a system, and models in detail four of its evolutionary evolutionary phases: mass transfer through the ongoing X-ray phase, tidal evolution before the onset of Roche-lobe overflow, motion through the Galactic potential after the formation of the black hole, and binary orbital dynamics at the time of core collapse. Motivated by deep extra-galactic Chandra survey observations, I worked on population synthesis models of low-mass X-ray binaries in the two elliptical galaxies NGC3379 and NGC4278. These simulations were targeted at understanding the origin of the shape and normalization of the observed X-ray luminosity functions. In a follow up study, I proposed a physically motivated prescription for the modeling of transient neutron star low-mass X-ray binary properties, such as duty cycle, outburst duration and recurrence time. This prescription enabled the direct comparison of transient low-mass X-ray binary population synthesis models to the Chandra X-ray survey of the two ellipticals NGC3379 and NGC4278. Finally, I worked on population synthesismodels of black holeX-ray binaries in the MilkyWay. This work was motivated by recent developments in observational techniques for the measurement of black hole spin magnitudes in black hole X-ray binaries. The accuracy of these techniques depend on misalignment of the black hole spin with respect to the orbital angular momentum. In black hole X-ray binaries, this misalignment can occur during the supernova explosion that forms the compact object. In this study, I presented population synthesis models of Galactic black hole X-ray binaries, and examined the distribution of misalignment angles, and its dependence on the model parameters.

An all sky study of fast X-ray transients. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Connors, Alanna

1988-01-01

In the HEAO 1 A-2 survey of fast X-ray transients, a search of 2 to 20 keV scanning data was made for brief increases in flux, greater than 4 millicrabs, on timescales approximately 1 to 10 to the 4th s above a 12-hour average. The search was divided into two regions, and all-sky survey of the Galaxy, and a survey of the Magellanic Clouds. In the latter, 37 events were found and identified with 4 of the 5 brighest sources in the LMC, plus 2 as flares from a foreground star. Np X-ray bursts, no gamma-ray bursts, and no events from the SMC were found. In the all-sky survey, after excluding well-known variable sources, out of the equivalent of approximately 104 days of data, 15 events were found which falling into 2 broad categories: flares from coronal sources, roughly isotropically distributed, with optically thin thermal spectra; and harder fast transients apparently distributed near the Galactic plane. The first were identified as flares from ubiquitous active cool dwarf stars. It was hypothesized that the second may have been from distant Be-neutron star binaries. However, at least two of the harder, more luminous events remained unidentified. Future research should examine the nature of these rare events, and how they may fit into a hierarchy of hard fast transients from gamma-ray bursts to outbursts from pulsar systems.

DISCOVERY OF RAPIDLY MOVING PARTIAL X-RAY ABSORBERS WITHIN GAMMA CASSIOPEIAE

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

Hamaguchi, K.; Oskinova, L.; Russell, C. M. P.

2016-12-01

Gamma Cassiopeiae is an enigmatic Be star with unusually strong hard X-ray emission. The Suzaku observatory detected six rapid X-ray spectral hardening events called “softness dips” in a ∼100 ks observation in 2011. All the softness dip events show symmetric softness-ratio variations, and some of them have flat bottoms apparently due to saturation. The softness dip spectra are best described by either ∼40% or ∼70% partial covering absorption to kT  ∼ 12 keV plasma emission by matter with a neutral hydrogen column density of ∼(2−8) × 10{sup 21} cm{sup −2}, while the spectrum outside these dips is almost free of absorption. This resultmore » suggests the presence of two distinct X-ray-emitting spots in the γ  Cas system, perhaps on a white dwarf (WD) companion with dipole mass accretion. The partial covering absorbers may be blobs in the Be stellar wind, the Be disk, or rotating around the WD companion. Weak correlations of the softness ratios to the hard X-ray flux suggest the presence of stable plasmas at kT  ∼ 0.9 and 5 keV, which may originate from the Be or WD winds. The formation of a Be star and WD binary system requires mass transfer between two stars; γ  Cas may have experienced such activity in the past.« less

X-ray Spectral Analysis of the Cataclysmic Variable LS Peg using XMM-Newton Observatory Data

NASA Astrophysics Data System (ADS)

Talebpour Sheshvan, N.; Nabizadeh, A.; Balman, S.

2017-10-01

LS Peg is a Cataclysmic Variable (CV) suggested as Intermediate Polar (IP) because of similar properties to those observed in IP systems. We used archival XMM-Newton observation of LS Peg in order to study the X-ray characteristics of the system. We show LS Peg light curves in several different energy bands, and discuss about orbital modulations and power spectral analysis. Unlike the previous spectral analysis of the EPIC-MOS data by fitting a hot optically thin plasma emission model with a single temperature, we simultaneously fit EPIC spectrum (pn+MOS) using a composite model of absorption (tbabs) along with two different partial covering absorbers plus a multi-temperature plasma emission component in XSPEC. In addition, we find a Gaussian emission line at 6.4 keV. For LS Peg the maximum temperature of the plasma distribution is found to be ˜ 17.8 keV with a luminosity of ˜ 7.4×10^{32}erg s^{-1} translating to an accretion rate of ˜ 1.7×10 ^{-10} M_{⊙} yr^{-1}. We present spectra for orbital minimum and orbital maximum. In addition, we use SWIFT observations of the source in order to make a comparison. We elaborate on the geometry of accretion and absorption in the X-ray emitting region with articulation on the magnetic nature.

The Fate of Neutron Star Binary Mergers

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

Piro, Anthony L.; Giacomazzo, Bruno; Perna, Rosalba, E-mail: piro@carnegiescience.edu

Following merger, a neutron star (NS) binary can produce roughly one of three different outcomes: (1) a stable NS, (2) a black hole (BH), or (3) a supramassive, rotationally supported NS, which then collapses to a BH following angular momentum losses. Which of these fates occur and in what proportion has important implications for the electromagnetic transient associated with the mergers and the expected gravitational wave (GW) signatures, which in turn depend on the high density equation of state (EOS). Here we combine relativistic calculations of NS masses using realistic EOSs with Monte Carlo population synthesis based on the massmore » distribution of NS binaries in our Galaxy to predict the distribution of fates expected. For many EOSs, a significant fraction of the remnants are NSs or supramassive NSs. This lends support to scenarios in which a quickly spinning, highly magnetized NS may be powering an electromagnetic transient. This also indicates that it will be important for future GW observatories to focus on high frequencies to study the post-merger GW emission. Even in cases where individual GW events are too low in signal to noise to study the post merger signature in detail, the statistics of how many mergers produce NSs versus BHs can be compared with our work to constrain the EOS. To match short gamma-ray-burst (SGRB) X-ray afterglow statistics, we find that the stiffest EOSs are ruled out. Furthermore, many popular EOSs require a significant fraction of ∼60%–70% of SGRBs to be from NS–BH mergers rather than just binary NSs.« less

Design and Performance of the GAMMA-400 Gamma-Ray Telescope for Dark Matter Searches

NASA Technical Reports Server (NTRS)

Galper, A.M.; Adriani, O.; Aptekar, R. L.; Arkhangelskaja, I. V.; Arkhangelskiy, A.I.; Boezio, M.; Bonvicini, V.; Boyarchuk, K. A.; Fradkin, M. I.; Gusakov, Yu. V.;

Design and Performance of the GAMMA-400 Gamma-Ray Telescope for Dark Matter Searches

NASA Technical Reports Server (NTRS)

Galper, A. M.; Adriani, O.; Aptekar, R. L.; Arkhangelskaja, I. V.; Arkhangelskiy, A. I.; Boezio, M.; Bonvicini, V.; Boyarchuk, K. A.; Fradkin, M. I.; Gusakov, Yu V.;

High energy gamma-ray astronomy; Proceedings of the International Conference, ANN Arbor, MI, Oct. 2-5, 1990

NASA Astrophysics Data System (ADS)

Matthews, James

The present volume on high energy gamma-ray astronomy discusses the composition and properties of heavy cosmic rays greater than 10 exp 12 eV, implications of the IRAS Survey for galactic gamma-ray astronomy, gamma-ray emission from young neutron stars, and high-energy diffuse gamma rays. Attention is given to observations of TeV photons at the Whipple Observatory, TeV gamma rays from millisecond pulsars, recent data from the CYGNUS experiment, and recent results from the Woomera Telescope. Topics addressed include bounds on a possible He/VHE gamma-ray line signal of Galactic dark matter, albedo gamma rays from cosmic ray interactions on the solar surface, source studies, and the CANGAROO project. Also discussed are neural nets and other methods for maximizing the sensitivity of a low-threshold VHE gamma-ray telescope, a prototype water-Cerenkov air-shower detector, detection of point sources with spark chamber gamma-ray telescopes, and real-time image parameterization in high energy gamma-ray astronomy using transputers. (For individual items see A93-25002 to A93-25039)

Topics in High-Energy Astrophysics: X-ray Time Lags and Gamma-ray Flares

NASA Astrophysics Data System (ADS)

Kroon, John J.

2016-03-01

The Universe is host to a wide variety of high-energy processes that convert gravitational potential energy or rest-mass energy into non-thermal radiation such as bremsstrahlung and synchrotron. Prevailing models of X-ray emission from accreting Black Hole Binaries (BHBs) struggle to simultaneously fit the quiescent X-ray spectrum and the transients which result in the phenomenon known as X-ray time lags. And similarly, classical models of diffusive shock acceleration in pulsar wind nebulae fail to explain the extreme particle acceleration in very short timescales as is inferred from recent gamma-ray flares from the Crab nebula. In this dissertation, I develop new exact analytic models to shed light on these intriguing processes. I take a fresh look at the formation of X-ray time lags in compact sources using a new mathematical approach in which I obtain the exact Green's function solution. The resulting Green's function allows one to explore a variety of injection scenarios, including both monochromatic and broadband (bremsstrahlung) seed photon injection. I obtain the exact solution for the dependence of the time lags on the Fourier frequency, for both homogeneous and inhomogeneous clouds. The model can successfully reproduce both the observed time lags and the quiescent X-ray spectrum using a single set of coronal parameters. I show that the implied coronal radii in the new model are significantly smaller than those obtained in the Monte Carlo simulations, hence greatly reducing the coronal heating problem. Recent bright gamma-ray flares from the Crab nebula observed by AGILE and Fermi reaching GeV energies and lasting several days challenge the contemporary model for particle acceleration in pulsar wind nebulae, specifically the diffusive shock acceleration model. Simulations indicate electron/positron pairs in the Crab nebula pulsar wind must be accelerated up to PeV energies in the presence of ambient magnetic fields with strength B ~100 microG. No comprehensive model has been presented that simultaneously and self-consistently explains the energetic and temporal properties of the observed flares. In this component of my dissertation research, I revisit the problem based on an analytical approach using a transport equation that includes terms describing electrostatic acceleration, stochastic wave-particle acceleration, synchrotron losses, and particle escape. I obtain an exact solution and use it to compute the resulting gamma-ray synchrotron spectrum. I find that the spectra of all the Fermi-LAT flares from the Crab nebula can be reproduced with this model using magnetic fields that are in agreement with multi-wavelength observations.

Very high-energy gamma rays from gamma-ray bursts.

PubMed

Chadwick, Paula M

2007-05-15

Very high-energy (VHE) gamma-ray astronomy has undergone a transformation in the last few years, with telescopes of unprecedented sensitivity having greatly expanded the source catalogue. Such progress makes the detection of a gamma-ray burst at the highest energies much more likely than previously. This paper describes the facilities currently operating and their chances for detecting gamma-ray bursts, and reviews predictions for VHE gamma-ray emission from gamma-ray bursts. Results to date are summarized.

Sneaky Gamma-Rays: Using Gravitational Lensing to Avoid Gamma-Gamma-Absorption

NASA Astrophysics Data System (ADS)

Boettcher, Markus; Barnacka, Anna

2014-08-01

It has recently been suggested that gravitational lensing studies of gamma-ray blazars might be a promising avenue to probe the location of the gamma-ray emitting region in blazars. Motivated by these prospects, we have investigated potential gamma-gamma absorption signatures of intervening lenses in the very-high-energy gamma-ray emission from lensedblazars. We considered intervening galaxies and individual stars within these galaxies. We find that the collective radiation field of galaxies acting as sources of macrolensing are not expected to lead to significant gamma-gamma absorption. Individual stars within intervening galaxies could, in principle, cause a significant opacity to gamma-gamma absorption for VHE gamma-rays if the impact parameter (the distance of closest approach of the gamma-ray to the center of the star) is small enough. However, we find that the curvature of the photon path due to gravitational lensing will cause gamma-ray photons to maintain a sufficiently large distance from such stars to avoid significant gamma-gamma absorption. This re-inforces the prospect of gravitational-lensing studies of gamma-ray blazars without interference due to gamma-gamma absorption due to the lensing objects.

Transformation of a Spatial Map across the Hippocampal-Lateral Septal Circuit.

PubMed

Tingley, David; Buzsáki, György

2018-05-15

The hippocampus constructs a map of the environment. How this "cognitive map" is utilized by other brain regions to guide behavior remains unexplored. To examine how neuronal firing patterns in the hippocampus are transmitted and transformed, we recorded neurons in its principal subcortical target, the lateral septum (LS). We observed that LS neurons carry reliable spatial information in the phase of action potentials, relative to hippocampal theta oscillations, while the firing rates of LS neurons remained uninformative. Furthermore, this spatial phase code had an anatomical microstructure within the LS and was bound to the hippocampal spatial code by synchronous gamma frequency cell assemblies. Using a data-driven model, we show that rate-independent spatial tuning arises through the dynamic weighting of CA1 and CA3 cell assemblies. Our findings demonstrate that transformation of the hippocampal spatial map depends on higher-order theta-dependent neuronal sequences. Copyright © 2018 Elsevier Inc. All rights reserved.

On the nature of short and long gamma-ray bursts

NASA Astrophysics Data System (ADS)

Ruffini, Remo; Fryer, Chris; Muccino, Marco; Rueda Hernandez, Jorge

2016-03-01

For a long GRB (L-GRB) the induced gravitational collapse (IGC) paradigm proposes as progenitor a binary system made up of a carbon-oxygen core undergoing a supernova (SN) that triggers hypercritical accretion onto a neutron star (NS) companion. For a short GRB (S-GRB), a NS-NS merger is adopted. We divide L-GRBs and S-GRBs into subclasses, depending whether or not a black hole (BH) is formed. For long bursts, when no BH is formed we have the X-ray flashes (XRFs), with isotropic energy Eiso <=1052 erg and rest-frame spectral peak energy Ep , i <= 200 keV. When a BH is formed we have authentic L-GRBs, with Eiso >1052 erg and Ep , i > 200 keV. For short bursts, when no BH is formed we have short gamma-ray flashes (S-GRFs) with Eiso <=1052 erg and Ep , i <= 2 MeV, while an authentic S-GRBs occur if BH is formed, with Eiso >1052 erg and Ep , i > 2 MeV. We give examples and observational signatures of the four subclasses. In the case of S-GRBs and BdHNe evidence is given of the coincidence of the onset of the high-energy GeV emission with the birth of a Kerr-Newman BH.

Design and performance of the GAMMA-400 gamma-ray telescope for dark matter searches

NASA Astrophysics Data System (ADS)

Galper, A. M.; Adriani, O.; Aptekar, R. L.; Arkhangelskaja, I. V.; Arkhangelskiy, A. I.; Boezio, M.; Bonvicini, V.; Boyarchuk, K. A.; Fradkin, M. I.; Gusakov, Yu. V.; Kaplin, V. A.; Kachanov, V. A.; Kheymits, M. D.; Leonov, A. A.; Longo, F.; Mazets, E. P.; Maestro, P.; Marrocchesi, P.; Mereminskiy, I. A.; Mikhailov, V. V.; Moiseev, A. A.; Mocchiutti, E.; Mori, N.; Moskalenko, I. V.; Naumov, P. Yu.; Papini, P.; Picozza, P.; Rodin, V. G.; Runtso, M. F.; Sparvoli, R.; Spillantini, P.; Suchkov, S. I.; Tavani, M.; Topchiev, N. P.; Vacchi, A.; Vannuccini, E.; Yurkin, Yu. T.; Zampa, N.; Zverev, V. G.; Zirakashvili, V. N.

2013-02-01

The GAMMA-400 gamma-ray telescope is designed to measure the fluxes of gamma-rays and cosmic-ray electrons + positrons, which can be produced by annihilation or decay of the dark matter particles, as well as to survey the celestial sphere in order to study point and extended sources of gamma-rays, measure energy spectra of Galactic and extragalactic diffuse gamma-ray emission, gamma-ray bursts, and gamma-ray emission from the Sun. GAMMA-400 covers the energy range from 100 MeV to 3000 GeV. Its angular resolution is ~0.01° (Eγ > 100 GeV), the energy resolution ~1% (Eγ > 10 GeV), and the proton rejection factor ~106. GAMMA-400 will be installed on the Russian space platform Navigator. The beginning of observations is planned for 2018.

Constraining Accreting Binary Populations in Normal Galaxies

NASA Astrophysics Data System (ADS)

Lehmer, Bret; Hornschemeier, A.; Basu-Zych, A.; Fragos, T.; Jenkins, L.; Kalogera, V.; Ptak, A.; Tzanavaris, P.; Zezas, A.

2011-01-01

X-ray emission from accreting binary systems (X-ray binaries) uniquely probe the binary phase of stellar evolution and the formation of compact objects such as neutron stars and black holes. A detailed understanding of X-ray binary systems is needed to provide physical insight into the formation and evolution of the stars involved, as well as the demographics of interesting binary remnants, such as millisecond pulsars and gravitational wave sources. Our program makes wide use of Chandra observations and complementary multiwavelength data sets (through, e.g., the Spitzer Infrared Nearby Galaxies Survey [SINGS] and the Great Observatories Origins Deep Survey [GOODS]), as well as super-computing facilities, to provide: (1) improved calibrations for correlations between X-ray binary emission and physical properties (e.g., star-formation rate and stellar mass) for galaxies in the local Universe; (2) new physical constraints on accreting binary processes (e.g., common-envelope phase and mass transfer) through the fitting of X-ray binary synthesis models to observed local galaxy X-ray binary luminosity functions; (3) observational and model constraints on the X-ray evolution of normal galaxies over the last 90% of cosmic history (since z 4) from the Chandra Deep Field surveys and accreting binary synthesis models; and (4) predictions for deeper observations from forthcoming generations of X-ray telesopes (e.g., IXO, WFXT, and Gen-X) to provide a science driver for these missions. In this talk, we highlight the details of our program and discuss recent results.

Surface sodium lignosulphonate-immobilized sawdust particle as an efficient adsorbent for capturing Hg2+ from aqueous solution.

PubMed

Gao, Shan; Luo, Tiantian; Zhou, Qi; Luo, Wenjun; Li, Haifeng; Jing, Luru

2018-05-01

In this work, the soluble sodium lignosulphonate (LS Na ) molecules were successfully grafted onto the surface of pine sawdust (PSD) particles to obtain an efficient adsorbent (PSD-LS) for removing Hg 2+ from wastewater. In advance, the surface of sawdust particles were carboxymethylated by chloroacetic acid, the LS Na would be anchored on the surface by a heterogeneous esterification reaction occurred between the hydroxyl of LS Na and carboxyl on PSD surface. The resultant product (PSD-LS) exhibited a good adsorption performance for Hg 2+ with adsorption capacity up to 164.77 mg/g and it was characterized by scanning electron microscope (SEM), energy dispersive X-ray diffraction (EDX), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The effects of pH, contact time, adsorption temperature and initial concentration on the adsorption of Hg 2+ were investigated. Results showed that the pseudo-second-order kinetics and Langmuir isotherm model could describe the adsorption process better. In addition, the composite adsorbent has outstanding reusability with high and stable desorption rates under several continuous cycle. These findings suggested that PSD-LS was a potential adsorbent to remove hazardous metal ions from wastewater. Copyright © 2018 Elsevier Inc. All rights reserved.

How I Learned to Stop Worrying and Love Eclipsing Binaries

NASA Astrophysics Data System (ADS)

Moe, Maxwell Cassady

Relatively massive B-type stars with closely orbiting stellar companions can evolve to produce Type Ia supernovae, X-ray binaries, millisecond pulsars, mergers of neutron stars, gamma ray bursts, and sources of gravitational waves. However, the formation mechanism, intrinsic frequency, and evolutionary processes of B-type binaries are poorly understood. As of 2012, the binary statistics of massive stars had not been measured at low metallicities, extreme mass ratios, or intermediate orbital periods. This thesis utilizes large data sets of eclipsing binaries to measure the physical properties of B-type binaries in these previously unexplored portions of the parameter space. The updated binary statistics provide invaluable insight into the formation of massive stars and binaries as well as reliable initial conditions for population synthesis studies of binary star evolution. We first compare the properties of B-type eclipsing binaries in our Milky Way Galaxy and the nearby Magellanic Cloud Galaxies. We model the eclipsing binary light curves and perform detailed Monte Carlo simulations to recover the intrinsic properties and distributions of the close binary population. We find the frequency, period distribution, and mass-ratio distribution of close B-type binaries do not significantly depend on metallicity or environment. These results indicate the formation of massive binaries are relatively insensitive to their chemical abundances or immediate surroundings. Second, we search for low-mass eclipsing companions to massive B-type stars in the Large Magellanic Cloud Galaxy. In addition to finding such extreme mass-ratio binaries, we serendipitously discover a new class of eclipsing binaries. Each system comprises a massive B-type star that is fully formed and a nascent low-mass companion that is still contracting toward its normal phase of evolution. The large low-mass secondaries discernibly reflect much of the light they intercept from the hot B-type stars, thereby producing sinusoidal variations in perceived brightness as they orbit. These nascent eclipsing binaries are embedded in the hearts of star-forming emission nebulae, and therefore provide a unique snapshot into the formation and evolution of massive binaries and stellar nurseries. We next examine a large sample of B-type eclipsing binaries with intermediate orbital periods. To achieve such a task, we develop an automated pipeline to classify the eclipsing binaries, measure their physical properties from the observed light curves, and recover the intrinsic binary statistics by correcting for selection effects. We find the population of massive binaries at intermediate separations differ from those orbiting in close proximity. Close massive binaries favor small eccentricities and have correlated component masses, demonstrating they coevolved via competitive accretion during their formation in the circumbinary disk. Meanwhile, B-type binaries at slightly wider separations are born with large eccentricities and are weighted toward extreme mass ratios, indicating the components formed relatively independently and subsequently evolved to their current configurations via dynamical interactions. By using eclipsing binaries as accurate age indicators, we also reveal that the binary orbital eccentricities and the line-of-sight dust extinctions are anticorrelated with respect to time. These empirical relations provide robust constraints for tidal evolution in massive binaries and the evolution of the dust content in their surrounding environments. Finally, we compile observations of early-type binaries identified via spectroscopy, eclipses, long-baseline interferometry, adaptive optics, lucky imaging, high-contrast photometry, and common proper motion. We combine the samples from the various surveys and correct for their respective selection effects to determine a comprehensive nature of the intrinsic binary statistics of massive stars. We find the probability distributions of primary mass, secondary mass, orbital period, and orbital eccentricity are all interrelated. These updated multiplicity statistics imply a greater frequency of low-mass X-ray binaries, millisecond pulsars, and Type Ia supernovae than previously predicted.

Supergiant fast X-ray transients with Swift: Spectroscopic and temporal properties

NASA Astrophysics Data System (ADS)

Romano, P.; Mangano, V.; Ducci, L.; Esposito, P.; Farinelli, R.; Ceccobello, C.; Vercellone, S.; Burrows, D. N.; Kennea, J. A.; Krimm, H. A.; Gehrels, N.

2012-12-01

Supergiant fast X-ray transients (SFXTs) are a class of high-mass X-ray binaries with possible counterparts in the high energy gamma rays. The Swift SFXT Project1 has conducted a systematic investigation of the properties of SFTXs on timescales ranging from minutes to years and in several intensity states (from bright flares, to intermediate intensity states, and down to almost quiescence). We also performed broad-band spectroscopy of outbursts, and intensity-selected spectroscopy outside of outbursts. We demonstrated that while the brightest phase of the outburst only lasts a few hours, further activity is observed at lower fluxes for a remarkably longer time, up to weeks. Furthermore, we assessed the fraction of the time these sources spend in each phase, and their duty cycle of inactivity. We present the most recent results from our investigation. The spectroscopic and, most importantly, timing properties of SFXTs we have uncovered with Swift will serve as a guide in search for the high energy emission from these enigmatic objects.

Theoretical models for stellar X-ray polarization in compact objects

NASA Technical Reports Server (NTRS)

Meszaros, P.

1991-01-01

Degenerate stellar objects are expected to be strong sources of polarized X-ray emission. This is particularly true for strongly magnetized neutron stars, e.g. accretion or rotation powered pulsars, and gamma ray bursters. In these, linear polarization degrees well in excess of 30 percent are expected. Weaker magnetic field stellar sources, such as old neutron stars in low mass binary systems, white dwarfs and black holes are expected to have polarization degrees in the range 1-3 percent. A great interest attaches to the detection of polarization in these objects, since this would provide invaluable information concerning the geometry, radiation mechanism and magnetic field strength, necessary for testing and proving models of the structure and evolution of stars in their late stages. In this paper we review the theoretical models of the production of polarized radiation in compact stellar X-ray sources, and discuss the possibility of detecting these properties using currently planned detectors to be flown in space.

Heat-Killed Lactobacillus salivarius and Lactobacillus johnsonii Reduce Liver Injury Induced by Alcohol In Vitro and In Vivo.

PubMed

Chuang, Cheng-Hung; Tsai, Cheng-Chih; Lin, En-Shyh; Huang, Chin-Shiu; Lin, Yun-Yu; Lan, Chuan-Ching; Huang, Chun-Chih

2016-10-31

The aim of the present study was to determine whether Lactobacillus salivarius (LS) and Lactobacillus johnsonii (LJ) prevent alcoholic liver damage in HepG2 cells and rat models of acute alcohol exposure. In this study, heat-killed LS and LJ were screened from 50 Lactobacillus strains induced by 100 mM alcohol in HepG2 cells. The severity of alcoholic liver injury was determined by measuring the levels of aspartate transaminase (AST), alanine transaminase (ALT), gamma-glutamyl transferase (γ-GT), lipid peroxidation, triglyceride (TG) and total cholesterol. Our results indicated that heat-killed LS and LJ reduced AST, ALT, γ-GT and malondialdehyde (MDA) levels and outperformed other bacterial strains in cell line studies. We further evaluated these findings by administering these strains to rats. Only LS was able to reduce serum AST levels, which it did by 26.2%. In addition LS significantly inhibited serum TG levels by 39.2%. However, both strains were unable to inhibit ALT levels. In summary, we demonstrated that heat-killed LS and LJ possess hepatoprotective properties induced by alcohol both in vitro and in vivo.

The structure, logic of operation and distinctive features of the system of triggers and counting signals formation for gamma-telescope GAMMA-400

NASA Astrophysics Data System (ADS)

Topchiev, N. P.; Galper, A. M.; Arkhangelskiy, A. I.; Arkhangelskaja, I. V.; Kheymits, M. D.; Suchkov, S. I.; Yurkin, Y. T.

2017-01-01

Scientific project GAMMA-400 (Gamma Astronomical Multifunctional Modular Apparatus) relates to the new generation of space observatories intended to perform an indirect search for signatures of dark matter in the cosmic-ray fluxes, measurements of characteristics of diffuse gamma-ray emission and gamma-rays from the Sun during periods of solar activity, gamma-ray bursts, extended and point gamma-ray sources, electron/positron and cosmic-ray nuclei fluxes up to TeV energy region by means of the GAMMA-400 gamma-ray telescope represents the core of the scientific complex. The system of triggers and counting signals formation of the GAMMA-400 gamma-ray telescope constitutes the pipelined processor structure which collects data from the gamma-ray telescope subsystems and produces summary information used in forming the trigger decision for each event. The system design is based on the use of state-of-the-art reconfigurable logic devices and fast data links. The basic structure, logic of operation and distinctive features of the system are presented.

Properties of Neutrino-driven Ejecta from the Remnant of a Binary Neutron Star Merger: Pure Radiation Hydrodynamics Case

NASA Astrophysics Data System (ADS)

Fujibayashi, Sho; Sekiguchi, Yuichiro; Kiuchi, Kenta; Shibata, Masaru

2017-09-01

We performed general relativistic, long-term, axisymmetric neutrino radiation hydrodynamics simulations for the remnant formed after a binary neutron star merger, which consists of a massive neutron star and a torus surrounding it. As an initial condition, we employ the result derived in a three-dimensional, numerical relativity simulation for the binary neutron star merger. We investigate the properties of neutrino-driven ejecta. Due to the pair-annihilation heating, the dynamics of the neutrino-driven ejecta are significantly modified. The kinetic energy of the ejecta is about two times larger than that in the absence of pair-annihilation heating. This suggests that the pair-annihilation heating plays an important role in the evolution of merger remnants. The relativistic outflow, which is required for driving gamma-ray bursts, is not observed because the specific heating rate around the rotational axis is not sufficiently high, due to the baryon loading caused by the neutrino-driven ejecta from the massive neutron star. We discuss the condition for launching the relativistic outflow and the nucleosynthesis in the ejecta.

Compact binary merger and kilonova: outflows from remnant disc

NASA Astrophysics Data System (ADS)

Yi, Tuan; Gu, Wei-Min; Liu, Tong; Kumar, Rajiv; Mu, Hui-Jun; Song, Cui-Ying

2018-05-01

Outflows launched from a remnant disc of compact binary merger may have essential contribution to the kilonova emission. Numerical calculations are conducted in this work to study the structure of accretion flows and outflows. By the incorporation of limited-energy advection in the hyper-accretion discs, outflows occur naturally from accretion flows due to imbalance between the viscous heating and the sum of the advective and radiative cooling. Following this spirit, we revisit the properties of the merger outflow ejecta. Our results show that around 10-3 ˜ 10-1 M⊙ of the disc mass can be launched as powerful outflows. The amount of unbound mass varies with the disc mass and the viscosity. The outflow-contributed peak luminosity is around 1040 ˜ 1041 erg s-1. Such a scenario can account for the observed kilonovae associated with short gamma-ray bursts, including the recent event AT2017gfo (GW170817).

High energy resolution observation of the Crab and AO535 plus 26 in the hard X-ray range

NASA Technical Reports Server (NTRS)

Hameury, J. M.; Boclet, D.; Durouchoux, P.; Cline, T.; Teegarden, B.; Tueller, J.; Paciesas, W.; Haymes, R.

1982-01-01

A number of uncertainties exist currently regarding the existence of gamma-ray lines in the Crab spectrum. An investigation was, therefore, conducted, and the Crab was observed for eight hours during a balloon flight from Palestine, TX, on September 26, 1980. It appeared that the binary source AO535 plus 26 contaminated the Crab data. It was, however, possible to separate the two sources. The obtained results are discussed and evaluated. It is found that the possibility of a line at 73 keV with the intensity reported by Ling et al. (1979) can be excluded for the obtained data. The 400 keV line cannot be ruled out. The results concerning AO535 plus 26 are very different from those previously obtained.

Day-Scale Variability of 3C 279 and Searches for Correlations in Gamma-Ray, X-Ray and Optical Bands

NASA Technical Reports Server (NTRS)

Hartman, R. C.; Villata, M.; Balonek, T. J.; Bertsch, D. L.; Bock, H.; Boettcher, M.; Carini, M. T.; Collmar, W.; DeFrancesco, G.; Ferrera, E. C.;

Direction-Sensitive Hand-Held Gamma-Ray Spectrometer

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

Mukhopadhyay, S.

2012-10-04

A novel, light-weight, hand-held gamma-ray detector with directional sensitivity is being designed. The detector uses a set of multiple rings around two cylindrical surfaces, which provides precise location of two interaction points on two concentric cylindrical planes, wherefrom the source location can be traced back by back projection and/or Compton imaging technique. The detectors are 2.0 × 2.0 mm europium-doped strontium iodide (SrI2:Eu2+) crystals, whose light output has been measured to exceed 120,000 photons/MeV, making it one of the brightest scintillators in existence. The crystal’s energy resolution, less than 3% at 662 keV, is also excellent, and the response ismore » highly linear over a wide range of gamma-ray energies. The emission of SrI2:Eu2+ is well matched to both photo-multiplier tubes and blue-enhanced silicon photodiodes. The solid-state photomultipliers used in this design (each 2.0 × 2.0 mm) are arrays of active pixel sensors (avalanche photodiodes driven beyond their breakdown voltage in reverse bias); each pixel acts as a binary photon detector, and their summed output is an analog representation of the total photon energy, while the individual pixel accurately defines the point of interaction. A simple back-projection algorithm involving cone-surface mapping is being modeled. The back projection for an event cone is a conical surface defining the possible location of the source. The cone axis is the straight line passing through the first and second interaction points.« less

Analysis of Geothermal Reservoir and Well Operational Conditions using Monthly Production Reports from Nevada and California

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

Beckers, Koenraad J; Young, Katherine R; Johnston, Henry

When conducting techno-economic analysis of geothermal systems, assumptions are typically necessary for reservoir and wellbore parameters such as producer/injector well ratio, production temperature drawdown, and production/injection temperature, pressure and flow rate. To decrease uncertainty of several of these parameters, we analyzed field data reported by operators in monthly production reports. This paper presents results of a statistical analysis conducted on monthly production reports at 19 power plants in California and Nevada covering 196 production wells and 175 injection wells. The average production temperature was 304 degrees F (151 degrees C) for binary plants and 310 degrees F (154 degrees C)more » for flash plants. The average injection temperature was 169 degrees F (76 degrees C) for binary plants and 173 degrees F (78 degrees C) for flash plants. The average production temperature drawdown was 0.5% per year for binary plants and 0.8% per year for flash plants. The average production well flow rate was 112 L/s for binary plant wells and 62 L/s for flash plant wells. For all 19 plants combined, the median injectivity index value was 3.8 L/s/bar, and the average producer/injector well ratio was 1.6. As an additional example of analysis using data from monthly production reports, a coupled reservoir-wellbore model was developed to derive productivity curves at various pump horsepower settings. The workflow and model were applied to two example production wells.« less

Does mass accretion lead to field decay in neutron stars

NASA Technical Reports Server (NTRS)

Shibazaki, N.; Murakami, T.; Shaham, Jacob; Nomoto, K.

1989-01-01

The recent discovery of cyclotron lines from gamma-ray bursts indicates that the strong magnetic fields of isolated neutron stars might not decay. The possible inverse correlation between the strength of the magnetic field and the mass accreted by the neutron star suggests that mass accretion itself may lead to the decay of the magnetic field. The spin and magnetic field evolution of the neutron star was calculated under the hypothesis of the accretion-induced field decay. It is shown that the calculated results are consistent with the observations of binary and millisecond radio pulsars.

The Compton Observatory Science Workshop

NASA Technical Reports Server (NTRS)

Shrader, Chris R. (Editor); Gehrels, Neil (Editor); Dennis, Brian (Editor)

1992-01-01

The Compton Observatory Science Workshop was held in Annapolis, Maryland on September 23-25, 1991. The primary purpose of the workshop was to provide a forum for the exchange of ideas and information among scientists with interests in various areas of high energy astrophysics, with emphasis on the scientific capabilities of the Compton Observatory. Early scientific results, as well as reports on in-flight instrument performance and calibrations are presented. Guest investigator data products, analysis techniques, and associated software were discussed. Scientific topics covered included active galaxies, cosmic gamma ray bursts, solar physics, pulsars, novae, supernovae, galactic binary sources, and diffuse galactic and extragalactic emission.

Cosmic Catastrophes

NASA Astrophysics Data System (ADS)

Wheeler, J. Craig

2014-08-01

Preface; 1. Setting the stage: star formation and hydrogen burning in single stars; 2. Stellar death: the inexorable grip of gravity; 3. Dancing with stars: binary stellar evolution; 4. Accretion disks: flat stars; 5. White Dwarfs: quantum dots; 6. Supernovae: stellar catastrophes; 7. Supernova 1987A: lessons and enigmas; 8. Neutron stars: atoms with attitude; 9. Black holes in theory: into the abyss; 10. Black holes in fact: exploring the reality; 11. Gamma-ray bursts, black holes and the universe: long, long ago and far, far away; 12. Supernovae and the universe; 13. Worm holes and time machines: tunnels in space and time; 14. Beyond: the frontiers; Index.

Cosmic Catastrophes

NASA Astrophysics Data System (ADS)

Wheeler, J. Craig

2007-01-01

Preface; 1. Setting the stage: star formation and hydrogen burning in single stars; 2. Stellar death: the inexorable grip of gravity; 3. Dancing with stars: binary stellar evolution; 4. Accretion disks: flat stars; 5. White Dwarfs: quantum dots; 6. Supernovae: stellar catastrophes; 7. Supernova 1987A: lessons and enigmas; 8. Neutron stars: atoms with attitude; 9. Black holes in theory: into the abyss; 10. Black holes in fact: exploring the reality; 11. Gamma-ray bursts, black holes and the universe: long, long ago and far, far away; 12. Supernovae and the universe; 13. Worm holes and time machines: tunnels in space and time; 14. Beyond: the frontiers; Index.

Basic Space Science; United Nations/European Space Agency Workshops for Developing Countries, 2nd, Bogota, Colombia, November 9-13, 1992

NASA Technical Reports Server (NTRS)

Haubold, Hans J. (Editor); Torres, Sergio (Editor)

1994-01-01

The conference primarily covered astrophysical and astronomical topics on stellar and solar modeling and processes, high magnetic field influence on stellar spectra, cosmological topics utilizing Cosmic Background Explorer (COBE) data and radioastronomic mapping as well as cosmic gravitational instability calculations, astrometry of open clusters amd solar gravitational focusing, extremely energetic gamma rays, interacting binaries, and balloon-borne instrumentation. Other papers proposed an active Search for Extraterrestrial Intelligence (SETI) communication scheme to neighboring solar-like systems and more direct involvement of and with the public in astronomy and space exploration projects.

Recent Results on SNRs and PWNe from the Fermi Large Area Telescope

NASA Technical Reports Server (NTRS)

Hays, Elizabeth

2010-01-01

a) Symbiotic Binary System: White dwarf + red giant system. b) Nova: White dwarf builds up mass envelope to the point of thermonuclear fusion. c) Dramatic increase in visual magnitude. d) Recurrent Nova? e) Hints but no strong confirmation of previous nova f) Pre-nova activity: 1) White dwarf shows ongoing variability at level of several in magnitude. 2) V407 Cyg companion is a Mira star showing variability at level of several in magnitude. g) Origin of the gamma rays? 1) Strong shock propagating into dense medium around giant star land stellar wind. 2) Pion decay or electron processes?

Unidentified Gamma-Ray Sources: Hunting Gamma-Ray Blazars

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

Massaro, F.; D'Abrusco, R.; Tosti, G.

2012-04-02

One of the main scientific objectives of the ongoing Fermi mission is unveiling the nature of the unidentified {gamma}-ray sources (UGSs). Despite the large improvements of Fermi in the localization of {gamma}-ray sources with respect to the past {gamma}-ray missions, about one third of the Fermi-detected objects are still not associated to low energy counterparts. Recently, using the Wide-field Infrared Survey Explorer (WISE) survey, we discovered that blazars, the rarest class of Active Galactic Nuclei and the largest population of {gamma}-ray sources, can be recognized and separated from other extragalactic sources on the basis of their infrared (IR) colors. Basedmore » on this result, we designed an association method for the {gamma}-ray sources to recognize if there is a blazar candidate within the positional uncertainty region of a generic {gamma}-ray source. With this new IR diagnostic tool, we searched for {gamma}-ray blazar candidates associated to the UGS sample of the second Fermi {gamma}-ray catalog (2FGL). We found that our method associates at least one {gamma}-ray blazar candidate as a counterpart each of 156 out of 313 UGSs analyzed. These new low-energy candidates have the same IR properties as the blazars associated to {gamma}-ray sources in the 2FGL catalog.« less

UNIDENTIFIED {gamma}-RAY SOURCES: HUNTING {gamma}-RAY BLAZARS

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

Massaro, F.; Ajello, M.; D'Abrusco, R.

2012-06-10

One of the main scientific objectives of the ongoing Fermi mission is unveiling the nature of unidentified {gamma}-ray sources (UGSs). Despite the major improvements of Fermi in the localization of {gamma}-ray sources with respect to the past {gamma}-ray missions, about one-third of the Fermi-detected objects are still not associated with low-energy counterparts. Recently, using the Wide-field Infrared Survey Explorer survey, we discovered that blazars, the rarest class of active galactic nuclei and the largest population of {gamma}-ray sources, can be recognized and separated from other extragalactic sources on the basis of their infrared (IR) colors. Based on this result, wemore » designed an association method for the {gamma}-ray sources to recognize if there is a blazar candidate within the positional uncertainty region of a generic {gamma}-ray source. With this new IR diagnostic tool, we searched for {gamma}-ray blazar candidates associated with the UGS sample of the second Fermi {gamma}-ray LAT catalog (2FGL). We found that our method associates at least one {gamma}-ray blazar candidate as a counterpart to each of 156 out of 313 UGSs analyzed. These new low-energy candidates have the same IR properties as the blazars associated with {gamma}-ray sources in the 2FGL catalog.« less

Implications of Gamma-Ray Transparency Constraints in Blazars: Minimum Distances and Gamma-Ray Collimation

NASA Technical Reports Server (NTRS)

Becker, Peter A.; Kafatos, Menas

1995-01-01

We develop a general expression for the gamma - gamma absorption coefficient, alpha(sub gamma(gamma)) for gamma-rays propagating in an arbitrary direction at an arbitrary point in space above an X-ray-emitting accretion disk. The X-ray intensity is assumed to vary as a power law in energy and radius between the outer disk radius, R(sub 0), and the inner radius, R(sub ms) which is the radius of marginal stability for a Schwarzschild black hole. We use our result for alpha(sub gamma(gamma)) to calculate the gamma - gamma optical depth, tau(sub gamma(gamma)) for gamma - rays created at height z and propagating at angle Phi relative to the disk axis, and we show that for Phi = 0 and z greater than or approx equal to R(sub 0), tau(sub gamma(gamma)) proportional to Epsilon(sup alpha)z(sup -2(alpha) - 3), where alpha is the X-ray spectral index and Epsilon is the gamma - ray energy. As an application, we use our formalism to compute the minimum distance between the central black hole and the site of production of the gamma-rays detected by EGRET during the 1991 June flare of 3C 279. In order to obtain an upper limit, we assume that all of the X-rays observed contemporaneously by Ginga were emitted by the disk. Our results suggest that the observed gamma - rays may have originated within less than or approx equal to 45 GM/sq c from a black hole of mass greater than or approx equal to 10(exp 9) solar mass, perhaps in active plasma located above the central funnel of the accretion disk. This raises the possibility of establishing a direct connection between the production of the observed gamma - rays and the accretion of material onto the black hole. We also consider the variation of the optical depth as a function of the angle of propagation Phi. Our results indicate that the "focusing" of the gamma - rays along the disk axis due to pair production is strong enough to explain the observed degree of alignment in blazar sources. If the gamma - rays are produced isotropically in gamma - ray blazars, then these objects should appear as bright MeV sources when viewed along off-axis lines of sight.

An Fe XXVI Absorption Line in the Persistent Spectrum of the Dipping Low Mass X-ray Binary 1A 1744-361

NASA Technical Reports Server (NTRS)

Gavriil, Fotis P.; Strohmayer, Tod E.; Bhattacharyya, Sudip

2009-01-01

We report on Chandra X-ray Observatory (CXO) High-Energy Transmission Grating (HETG) spectra of the dipping Low Mass X-ray Binary (LMXB) 1A 1744-361 during its July 2008 outburst. We find that its persistent emission is well modeled by a blackbody (kT approx. 1.0 keV) plus power-law (Gamma approx. 1.7) with an absorption edge at 7.6 keV. In the residuals of the combined spectrum we find a significant absorption line at 6.961+/-0.002 keV, consistent with the Fe XXVI (hydrogen-like Fe) 2 - 1 transition. We place an upper limit on the velocity of a redshifted flow of v < 221 km/s. We find an equivalent width for the line of 27+2/-3 eV, from which we determine a column density of 7+/-1 x 10(exp 17)/sq cm via a curve-of-growth analysis. Using XSTAR simulations, we place a lower limit on the ionization parameter of > 10(exp 3.6) erg cm/s. The properties of this line are consistent with those observed in other dipping LMXBs. Using Rossi X-ray Timing Explorer (RXTE) data accumulated during this latest outburst we present an updated color-color diagram which clearly shows that IA 1744-361 is an "atoll" source. Finally, using additional dips found in the RXTE and CXO data we provide an updated orbital period estimate of 52+/-5 minutes.

Spectral and Temporal Characteristics of LS PEG and TW PIC Using XMM-NEWTON Data

NASA Astrophysics Data System (ADS)

Talebpour Sheshvan, Nasrin; Balman, Solen

2016-07-01

We report the analysis of archival XMM-Newton X-ray observations of LS Peg and TW Pic. These are Cataclysmic Variables (CVs) suggested as Intermediate Polars (IPs), but unconfirmed in the X-rays. Identification of several periodic oscillations in the optical band hint them as IPs. Unlike the previous spectral analysis on the EPIC-MOS data by fitting a hot optically thin plasma emission model with a single temperature for LS Peg, we simultaneously fitted all EPIC spectrum (pn+MOS) using a composite model of absorption for interstellar medium (tbabs) with two different partial covering absorbers (pcfabs) including a multitemperature plasma emission component (cevmkl) and a Gaussian emission line at 6.4 keV. TW Pic is best modeled in a similar manner with only one partial covering absorber and an extra Gaussian emission line at 6.7 keV. LS Peg has a maximum plasma temperature of ˜14.8 keV with an X-ray luminosity of ˜5×10^{32}ergs ^{-1} translating to an accretion rate of ˜1.27×10^{-10}M _{⊙}yr ^{-1}. TW Pic shows kT _{max} ˜38.7 keV with an X-ray luminosity around 1.6×10^{33}ergs ^{-1} at an accretion rate of ˜4×10^{-10}M _{⊙}yr ^{-1}. In addition, we discuss orbital modulations in the X-rays and power spectral analysis, and derive the EPIC pn spectra for orbital minimum and orbital maximum phases for both sources. We elaborate on the geometry of accretion and absorption in the X-ray emitting regions of both sources with articulation on the magnetic nature.

Obituary: Patrick L. Nolan (1952-2011)

NASA Astrophysics Data System (ADS)

Digel, Seth

2011-12-01

Patrick Lee Nolan died at his home in Palo Alto, California, on November 6, 2011, from complications related to a brain tumor, glioblastoma multiforme, which had been diagnosed less than five months earlier. He was born in Colusa, California, on November 18, 1952. Pat was the only child of John Henry Nolan and Carol Lee Harris Nolan. For most of his childhood they lived in Grass Valley, California, where his father was a butcher and his mother was a surgical nurse. Pat graduated from the California Institute of Technology in 1974 with a B.S. in Physics and completed a Ph.D. at the University of California at San Diego in 1982. His graduate and professional career was devoted to high-energy astronomy. His loss is being keenly felt by his friends and colleagues around the world, including the members of the Chancel Choir of the Menlo Park Presbyterian Church, of which he was a member for 25 years. At U. C. San Diego, Pat worked on construction of the Hard X-ray and Low Energy Gamma Ray Experiment for the first High Energy Astronomy Observatory mission, which was launched in 1977. His Ph.D. thesis, supervised by Prof. Laurence E. Peterson, was based on data from this instrument and addressed variability of the high-energy emission from Cygnus X-1 and other black hole binary systems in the Milky Way. After he completed his Ph.D., Pat took a National Research Council postdoctoral research position at the Naval Research Laboratory in Washington, D.C. He worked there from 1982-1984 developing spectral analysis software and studying gamma-ray bursts using the gamma-ray spectrometer on the Solar Maximum Mission satellite. A paper in Nature setting constraining limits on positron-electron annihilation radiation in the spectra of bursts marked the culmination of his efforts. Pat was hired by Prof. Robert Hofstadter at Stanford University in 1984 to work on the Energetic Gamma-Ray Experiment Telescope (EGRET). As a co-investigator for EGRET, Pat worked on its calorimeter subsystem, including calibration at the Stanford Linear Accelerator Center (SLAC), as well as on data analysis software and methods. EGRET was carried into space by the Shuttle Atlantis in 1991 as part of the Compton Gamma Ray Observatory. He led analyses of gamma-ray pulsars and other astrophysical sources, including a major study of EGRET source variability, and he was a valued resource to the many EGRET graduate students at Stanford. Members of the EGRET team regularly turned to Pat for advice on statistical analysis issues. After the launch of the Compton Observatory, Pat became a member of a small group at Stanford University and SLAC that developed and promoted a new design for a next-generation gamma-ray telescope, based on modern solid-state detectors for particle physics detectors. The concept became the Gamma-ray Large Area Space Telescope mission, which was launched by NASA in 2008 and renamed the Fermi Gamma-ray Space Telescope. The scientific collaboration for the Large Area Telescope on Fermi has grown to about 400 members from a number of countries. Pat was a recognized expert in statistics and data analysis within the collaboration and as a member of the Publication Board developed the Web and database systems for internal review of scientific publications. Pat was unassuming, widely read, and knowledgeable in many fields. These qualities together with his quiet joy in science made him a valued friend and colleague to many. At the time of his death, Pat was a Senior Research Physicist in the Hansen Experimental Physics Laboratory at Stanford University.