Physics, Astrophysics and Cosmology with Gravitational Waves.
Sathyaprakash, B S; Schutz, Bernard F
2009-01-01
Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.
Physical response of light-time gravitational wave detectors
NASA Astrophysics Data System (ADS)
Koop, Michael J.; Finn, Lee Samuel
2014-09-01
Gravitational wave detectors are typically described as responding to gravitational wave metric perturbations, which are gauge-dependent and—correspondingly—unphysical quantities. This is particularly true for ground-based interferometric detectors, like LIGO, space-based detectors, like LISA and its derivatives, spacecraft Doppler tracking detectors, and pulsar timing array detectors. The description of gravitational waves, and a gravitational wave detector's response, to the unphysical metric perturbation has lead to a proliferation of false analogies and descriptions regarding how these detectors function, and true misunderstandings of the physical character of gravitational waves. Here we provide a fully physical and gauge-invariant description of the response of a wide class of gravitational wave detectors in terms of the Riemann curvature, the physical quantity that describes gravitational phenomena in general relativity. In the limit of high frequency gravitational waves, the Riemann curvature separates into two independent gauge-invariant quantities: a "background" curvature contribution and a "wave" curvature contribution. In this limit the gravitational wave contribution to the detector response reduces to an integral of the gravitational wave contribution of the curvature along the unperturbed photon path between components of the detector. The description presented here provides an unambiguous physical description of what a gravitational wave detector measures and how it operates, a simple means of computing corrections to a detectors response owing to general detector motion, a straightforward way of connecting the results of numerical relativity simulations to gravitational wave detection, and a basis for a general and fully relativistic pulsar timing formula.
Embedding nonrelativistic physics inside a gravitational wave
NASA Astrophysics Data System (ADS)
Bekaert, Xavier; Morand, Kevin
2013-09-01
Gravitational waves with parallel rays are known to have remarkable properties: their orbit space of null rays possesses the structure of a nonrelativistic spacetime of codimension-1. Their geodesics are in one-to-one correspondence with dynamical trajectories of a nonrelativistic system. Similarly, the null dimensional reduction of Klein-Gordon’s equation on this class of gravitational waves leads to a Schrödinger equation on curved space. These properties are generalized to the class of gravitational waves with a null Killing vector field, of which we propose a new geometric definition, as conformally equivalent to the previous class and such that the Killing vector field is preserved. This definition is instrumental for performing this generalization, as well as various applications. In particular, results on geodesic completeness are extended in a similar way. Moreover, the classification of the subclass with constant scalar invariants is investigated.
Testing Gravitational Physics with Space-based Gravitational-wave Observations
NASA Technical Reports Server (NTRS)
Baker, John G.
2011-01-01
Gravitational wave observations provide exceptional and unique opportunities for precision tests of gravitational physics, as predicted by general relativity (GR). Space-based gravitational wave measurements, with high signal-to-noise ratios and large numbers of observed events may provide the best-suited gravitational-wave observations for testing GR with unprecedented precision. These observations will be especially useful in testing the properties of gravitational waves and strong-field aspects of the theory which are less relevant in other observations. We review the proposed GR test based on observations of massive black hole mergers, extreme mass ratio inspirals, and galactic binary systems.
Josh Goldberg and the physical reality of gravitational waves
NASA Astrophysics Data System (ADS)
Saulson, Peter R.
2011-12-01
In this article, I pay tribute to the contributions made by Josh Goldberg toward our understanding that gravitational waves are genuine physical predictions of general relativity. Josh played a central role in developing our understanding of how a binary star system generates gravitational waves. Another key contribution came through his patronage of the 1957 Chapel Hill Conference, in his role as funding officer for the Air Force's support of research in gravitation. I examine in detail the discussion at the Chapel Hill Conference, and show how the question of the reality of gravitational waves was resolved by a recognition that one could, in principle, construct a detector for such waves. I trace the implications of this resolution in the work of Joseph Weber, who attended the Chapel Hill Conference, and of Rainer Weiss, who did not attend but who carefully studied the key paper that Felix Pirani presented there. I conclude with a brief discussion of how a few minor remaining puzzles were resolved some years later.
Gravitational wave background from Standard Model physics: qualitative features
Ghiglieri, J.; Laine, M. E-mail: laine@itp.unibe.ch
2015-07-01
Because of physical processes ranging from microscopic particle collisions to macroscopic hydrodynamic fluctuations, any plasma in thermal equilibrium emits gravitational waves. For the largest wavelengths the emission rate is proportional to the shear viscosity of the plasma. In the Standard Model at 0T > 16 GeV, the shear viscosity is dominated by the most weakly interacting particles, right-handed leptons, and is relatively large. We estimate the order of magnitude of the corresponding spectrum of gravitational waves. Even though at small frequencies (corresponding to the sub-Hz range relevant for planned observatories such as eLISA) this background is tiny compared with that from non-equilibrium sources, the total energy carried by the high-frequency part of the spectrum is non-negligible if the production continues for a long time. We suggest that this may constrain (weakly) the highest temperature of the radiation epoch. Observing the high-frequency part directly sets a very ambitious goal for future generations of GHz-range detectors.
Gravitational wave background from Standard Model physics: qualitative features
Ghiglieri, J.; Laine, M.
2015-07-16
Because of physical processes ranging from microscopic particle collisions to macroscopic hydrodynamic fluctuations, any plasma in thermal equilibrium emits gravitational waves. For the largest wavelengths the emission rate is proportional to the shear viscosity of the plasma. In the Standard Model at T>160 GeV, the shear viscosity is dominated by the most weakly interacting particles, right-handed leptons, and is relatively large. We estimate the order of magnitude of the corresponding spectrum of gravitational waves. Even though at small frequencies (corresponding to the sub-Hz range relevant for planned observatories such as eLISA) this background is tiny compared with that from non-equilibrium sources, the total energy carried by the high-frequency part of the spectrum is non-negligible if the production continues for a long time. We suggest that this may constrain (weakly) the highest temperature of the radiation epoch. Observing the high-frequency part directly sets a very ambitious goal for future generations of GHz-range detectors.
Gravitational waves from inflation
NASA Astrophysics Data System (ADS)
Guzzetti, M. C.; Bartolo, N.; Liguori, M.; Matarrese, S.
2016-09-01
The production of a stochastic background of gravitational waves is a fundamental prediction of any cosmological inflationary model. The features of such a signal encode unique information about the physics of the Early Universe and beyond, thus representing an exciting, powerful window on the origin and evolution of the Universe. We review the main mechanisms of gravitational-wave production, ranging from quantum fluctuations of the gravitational field to other mechanisms that can take place during or after inflation. These include e.g. gravitational waves generated as a consequence of extra particle production during inflation, or during the (p)reheating phase. Gravitational waves produced in inflation scenarios based on modified gravity theories and second-order gravitational waves are also considered. For each analyzed case, the expected power spectrum is given. We discuss the discriminating power among different models, associated with the validity/violation of the standard consistency relation between tensor-to-scalar ratio r and tensor spectral index nT. In light of the prospects for (directly/indirectly) detecting primordial gravitational waves, we give the expected present-day gravitational radiation spectral energy-density, highlighting the main characteristics imprinted by the cosmic thermal history, and we outline the signatures left by gravitational waves on the Cosmic Microwave Background and some imprints in the Large-Scale Structure of the Universe. Finally, current bounds and prospects of detection for inflationary gravitational waves are summarized.
Extracting Physics from Gravitational Waves from Core-Collapse Supernovae
NASA Astrophysics Data System (ADS)
Szczepanczyk, Marek; LIGO Collaboration
2017-01-01
Core-Collapse Supernovae (CCSN) are the spectacular and violent deaths of massive stars. In my presentation I will give an overview of searches targeting supernova signals in LIGO and Virgo data. In particular I will present results of a search for gravitational waves from CCSN, performed in initial LIGO and Virgo data including the methodology, upper limits and model exclusion statements. I will also describe the current efforts towards parameter estimation and waveform reconstruction.
Gravitational lensing of gravitational wave
NASA Astrophysics Data System (ADS)
Kei Wong, Wang; Ng, Kwan Yeung
2017-01-01
Gravitational lensing phenomena are widespread in electromagnetic astrophysics, and in principle may also be uncovered with gravitational waves. We examine gravitational wave events lensed by elliptical galaxies in the limit of geometric optics, where we expect to see multiple signals from the same event with different arrival times and amplitudes. By using mass functions for compact binaries from population-synthesis simulations and a lensing probability calculated from Planck data, we estimate the rate of lensed signals for future gravitational wave missions.
NASA Astrophysics Data System (ADS)
Conklin, John
2016-03-01
With the expected direct detection of gravitational waves by Advanced LIGO and pulsar timing arrays in the near future, and with the recent launch of LISA Pathfinder this can arguably be called the decade of gravitational waves. Low frequency gravitational waves in the mHz range, which can only be observed from space, provide the richest science and complement high frequency observatories on the ground. A space-based observatory will improve our understanding of the formation and growth of massive black holes, create a census of compact binary systems in the Milky Way, test general relativity in extreme conditions, and enable searches for new physics. LISA, by far the most mature concept for detecting gravitational waves from space, has consistently ranked among the nation's top priority large science missions. In 2013, ESA selected the science theme ``The Gravitational Universe'' for its third large mission, L3, under the Cosmic Visions Program, with a planned launch date of 2034. NASA has decided to join with ESA on the L3 mission as a junior partner and has recently assembled a study team to provide advice on how NASA might contribute to the European-led mission. This talk will describe these efforts and the activities of the Gravitational Wave Science Interest Group and the L3 Study Team, which will lead to the first space-based gravitational wave observatory.
A connection between atomic physics and gravitational wave spectroscopy
NASA Astrophysics Data System (ADS)
Fontes, Christopher J.; Fryer, Chris L.; Hungerford, Aimee L.
2017-03-01
Neutron star mergers are promising candidates for the observation of an electromagnetic signal coincident with gravitational waves. The properties of the ejecta produced during these events are expected to play an important role in the electromagnetic transients called macronovae. Characteristics of the ejecta include large velocity gradients and the presence of heavy r-process elements, which pose significant challenges to the accurate calculation of radiative opacities and radiation transport. For example, these opacities include a dense forest of bound-bound features arising from near-neutral lanthanide and actinide elements. Here we investigate the use of fine-structure, line-broadened opacities that take into account the motional Doppler broadening caused by the velocity gradients. The use of individual line profiles produces frequency-dependent opacities that are one to two orders of magnitude greater than those obtained with the commonly used expansion opacities in the Sobolev approximation. These lower opacities result in simulated emission from neutron star mergers that is significantly dimmer and shifted toward the infra-red spectrum than previously predicted.
Gravitational Waves from Gravitational Collapse.
Fryer, Chris L; New, Kimberly C B
2003-01-01
Gravitational wave emission from stellar collapse has been studied for more than three decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.
Gravitational Waves from Gravitational Collapse.
Fryer, Chris L; New, Kimberly C B
2011-01-01
Gravitational-wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion-induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.
Gravitational waves from gravitational collapse
Fryer, Christopher L; New, Kimberly C
2008-01-01
Gravitational wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.
NASA Technical Reports Server (NTRS)
Kelly, Bernard J.
2010-01-01
Einstein's General Theory of Relativity is our best classical description of gravity, and informs modern astronomy and astrophysics at all scales: stellar, galactic, and cosmological. Among its surprising predictions is the existence of gravitational waves -- ripples in space-time that carry energy and momentum away from strongly interacting gravitating sources. In my talk, I will give an overview of the properties of this radiation, recent breakthroughs in computational physics allowing us to calculate the waveforms from galactic mergers, and the prospect of direct observation with interferometric detectors such as LIGO and LISA.
Constraining gravity with hadron physics: neutron stars, modified gravity and gravitational waves
NASA Astrophysics Data System (ADS)
Llanes-Estrada, Felipe J.
2017-03-01
The finding of Gravitational Waves (GW) by the aLIGO scientific and VIRGO collaborations opens opportunities to better test and understand strong interactions, both nuclear-hadronic and gravitational. Assuming General Relativity holds, one can constrain hadron physics at a neutron star. But precise knowledge of the Equation of State and transport properties in hadron matter can also be used to constrain the theory of gravity itself. I review a couple of these opportunities in the context of modified f (R) gravity, the maximum mass of neutron stars, and progress in the Equation of State of neutron matter from the chiral effective field theory of QCD.
Those Elusive Gravitational Waves
ERIC Educational Resources Information Center
MOSAIC, 1976
1976-01-01
The presence of gravitational waves was predicted by Einstein in his theory of General Relativity. Since then, scientists have been attempting to develop a detector sensitive enough to measure these cosmic signals. Once the presence of gravitational waves is confirmed, scientists can directly study star interiors, galaxy cores, or quasars. (MA)
Advanced Gravitational Wave Detectors
NASA Astrophysics Data System (ADS)
Blair, D. G.; Howell, E. J.; Ju, L.; Zhao, C.
2012-02-01
Part I. An Introduction to Gravitational Wave Astronomy and Detectors: 1. Gravitational waves D. G. Blair, L. Ju, C. Zhao and E. J. Howell; 2. Sources of gravitational waves D. G. Blair and E. J. Howell; 3. Gravitational wave detectors D. G. Blair, L. Ju, C. Zhao, H. Miao, E. J. Howell, and P. Barriga; 4. Gravitational wave data analysis B. S. Sathyaprakash and B. F. Schutz; 5. Network analysis L. Wen and B. F. Schutz; Part II. Current Laser Interferometer Detectors: Three Case Studies: 6. The Laser Interferometer Gravitational-Wave Observatory P. Fritschel; 7. The VIRGO detector S. Braccini; 8. GEO 600 H. Lück and H. Grote; Part III. Technology for Advanced Gravitational Wave Detectors: 9. Lasers for high optical power interferometers B. Willke and M. Frede; 10. Thermal noise, suspensions and test masses L. Ju, G. Harry and B. Lee; 11. Vibration isolation: Part 1. Seismic isolation for advanced LIGO B. Lantz; Part 2. Passive isolation J-C. Dumas; 12. Interferometer sensing and control P. Barriga; 13. Stabilizing interferometers against high optical power effects C. Zhao, L. Ju, S. Gras and D. G. Blair; Part IV. Technology for Third Generation Gravitational Wave Detectors: 14. Cryogenic interferometers J. Degallaix; 15. Quantum theory of laser-interferometer GW detectors H. Miao and Y. Chen; 16. ET. A third generation observatory M. Punturo and H. Lück; Index.
Search for Gravitational Waves
NASA Astrophysics Data System (ADS)
Tsubono, K.
The current status of the experimental search for gravitational waves is reviewed here. The emphasis is on the Japanese TAMA project. We started operation of the TAMA300 laser interferometric detector in 1999, and are now collecting and analyzing observational data to search for gravitational wave signals.
Gravitational Waves from Neutron Stars
NASA Astrophysics Data System (ADS)
Kokkotas, Konstantinos
2016-03-01
Neutron stars are the densest objects in the present Universe, attaining physical conditions of matter that cannot be replicated on Earth. These unique and irreproducible laboratories allow us to study physics in some of its most extreme regimes. More importantly, however, neutron stars allow us to formulate a number of fundamental questions that explore, in an intricate manner, the boundaries of our understanding of physics and of the Universe. The multifaceted nature of neutron stars involves a delicate interplay among astrophysics, gravitational physics, and nuclear physics. The research in the physics and astrophysics of neutron stars is expected to flourish and thrive in the next decade. The imminent direct detection of gravitational waves will turn gravitational physics into an observational science, and will provide us with a unique opportunity to make major breakthroughs in gravitational physics, in particle and high-energy astrophysics. These waves, which represent a basic prediction of Einstein's theory of general relativity but have yet to be detected directly, are produced in copious amounts, for instance, by tight binary neutron star and black hole systems, supernovae explosions, non-axisymmetric or unstable spinning neutron stars. The focus of the talk will be on the neutron star instabilities induced by rotation and the magnetic field. The conditions for the onset of these instabilities and their efficiency in gravitational waves will be presented. Finally, the dependence of the results and their impact on astrophysics and especially nuclear physics will be discussed.
Towards Gravitational Wave Astronomy
NASA Astrophysics Data System (ADS)
Losurdo, Giovanni
This chapter is meant to introduce the reader to the forthcoming network of second-generation interferometric detectors of gravitational waves, at a time when their construction is close to completion and there is the ambition to detect gravitational waves for the first time in the next few years and open the way to gravitational wave astronomy. The legacy of first-generation detectors is discussed before giving an overview of the technology challenges that have been faced to make advanced detectors possible. The various aspects outlined here are then discussed in more detail in the subsequent chapters of the book.
Gravitational waves: A probe to the physics in the early universe
NASA Astrophysics Data System (ADS)
Huang, Qing-Guo
2015-10-01
Gravitational waves can escape from the big bang and can be taken as a probe to the physics, in particular the inflation, in the early universe. Planck scale is a fundamental scale for quantum theory of gravity. Requiring the excursion distance of inflaton in the field space during inflation yields an upper bound on the tensor-to-scalar ratio. For example, r < 7 × 10-4 for ns = 0.9645. In the typical inflationary scenario, we predict 1 - 2/N < ns < 1 and - 2/N2 < α s < 0 which are consistent with Planck data released in 2015 quite well. Subtracting the contribution of thermal dust measured by Planck, BICEP2 data implies r ≲ 0.08 which is the tightest bound on the tensor-to-scalar ratio from current experiments.
Astronomy's New Messengers: A traveling exhibit on gravitational-wave physics
NASA Astrophysics Data System (ADS)
Cavaglià, Marco; Hendry, Martin; Márka, Szabolcs; Reitze, David H.; Riles, Keith
2010-01-01
The Laser Interferometer Gravitational-wave Observatory exhibit Astronomy's New Messengers: Listening to the Universe with Gravitational Waves is traveling to colleges, universities, museums and other public institutions throughout the United States. Astronomy's New Messengers primarily communicates with an adolescent and young adult audience, potentially inspiring them into the field of science. Acknowledging that this audience is traditionally a difficult one to attract, the exhibit publicly announces itself in a charismatic fashion to reach its principal goals of broadening the community of people interested in science and encouraging interest in science among young people.
Gravitational-Wave Detection (ii). Current Gravitational Wave Detector Results
NASA Astrophysics Data System (ADS)
Kanda, Nobuyuki
2005-11-01
The workshop session C1ii was focused on the results of recent operating detectors. 10 speakers presented the latest results of each experiments: ALLEGRO, GEO, LIGO, TAMA and VIRGO experiments. There were reports about searches for gravitational waves in analysis of observation data. The results are of no detection of gravitational waves, but observational upper-limits of gravitational waves are improved.
Gravitational Waves: The Evidence Mounts
ERIC Educational Resources Information Center
Wick, Gerald L.
1970-01-01
Reviews the work of Weber and his colleagues in their attempts at detecting extraterrestial gravitational waves. Coincidence events recorded by special detectors provide the evidence for the existence of gravitational waves. Bibliography. (LC)
Gravitational waves from technicolor
Jaervinen, Matti; Sannino, Francesco; Kouvaris, Chris
2010-03-15
We investigate the production and possible detection of gravitational waves stemming from the electroweak phase transition in the early universe in models of minimal walking technicolor. In particular we discuss the two possible scenarios in which one has only one electroweak phase transition and the case in which the technicolor dynamics allows for multiple phase transitions.
The gravitational wave experiment
NASA Technical Reports Server (NTRS)
Bertotti, B.; Ambrosini, R.; Asmar, S. W.; Brenkle, J. P.; Comoretto, G.; Giampieri, G.; Less, L.; Messeri, A.; Wahlquist, H. D.
1992-01-01
Since the optimum size of a gravitational wave detector is the wave length, interplanetary dimensions are needed for the mHz band of interest. Doppler tracking of Ulysses will provide the most sensitive attempt to date at the detection of gravitational waves in the low frequency band. The driving noise source is the fluctuations in the refractive index of interplanetary plasma. This dictates the timing of the experiment to be near solar opposition and sets the target accuracy for the fractional frequency change at 3.0 x 10 exp -14 for integration times of the order of 1000 sec. The instrumentation utilized by the experiment is distributed between the radio systems on the spacecraft and the seven participating ground stations of the Deep Space Network and Medicina. Preliminary analysis is available of the measurements taken during the Ulysses first opposition test.
Primordial gravitational waves and cosmology.
Krauss, Lawrence M; Dodelson, Scott; Meyer, Stephan
2010-05-21
The observation of primordial gravitational waves could provide a new and unique window on the earliest moments in the history of the universe and on possible new physics at energies many orders of magnitude beyond those accessible at particle accelerators. Such waves might be detectable soon, in current or planned satellite experiments that will probe for characteristic imprints in the polarization of the cosmic microwave background, or later with direct space-based interferometers. A positive detection could provide definitive evidence for inflation in the early universe and would constrain new physics from the grand unification scale to the Planck scale.
NASA Astrophysics Data System (ADS)
Finn, L. S.
Astronomers rely on a multiplicity of observational perspectives in order to infer the nature of the Universe. Progress in astronomy has historically been associated with new or improved observational perspectives. Gravitational wave detectors now under construction will provide us with a perspective on the Universe fundamentally different from any we have come to know. With this new perspective comes the hope of new insights and understanding, not just of exotic astrophysical processes, but of "bread-and-butter" astrophysics: e.g., stars and stellar evolution, galaxy formation and evolution, neutron star structure, and cosmology. In this report the author discusses briefly a small subset of the areas of conventional, "bread-and-butter" astrophysics where we can reasonably hope that gravitational wave observations will provide us with valuable new insights and understandings.
From Measure Zero to Measure Hero: Periodic Kerr Orbits and Gravitational Wave Physics
NASA Astrophysics Data System (ADS)
Perez-Giz, Gabriel
2011-12-01
A direct observational detection of gravitational waves -- perhaps the most fundamental prediction of a theory of curved spacetime -- looms close at hand. Stellar mass compact objects spiraling into supermassive black holes have received particular attention as sources of gravitational waves detectable by space-based gravitational wave observatories. A well-established approach models such an extreme mass ratio inspirals (EMRI) as an adiabatic progression through a series of Kerr geodesics. Thus, the direct detection of gravitational radiation from EMRIs and the extraction of astrophysical information from those waveforms require a thorough knowledge of the underlying geodesic dynamics. This dissertation adopts a dynamical systems approach to the study of Kerr orbits, beginning with equatorial orbits. We deduce a topological taxonomy of orbits that hinges on a correspondence between periodic orbits and rational numbers. The taxonomy defines the entire dynamics, including aperiodic motion, since every orbit is in or near the periodic set. A remarkable implication of this periodic orbit taxonomy is that the simple precessing ellipse familiar from planetary orbits is not allowed in the strong-field regime. Instead, eccentric orbits trace out precessions of multi-leaf clovers in the final stages of inspiral. Furthermore, for any black hole, there is some orbital angular momentum value in the strong-field regime below which zoom-whirl behavior becomes unavoidable. We then generalize the taxonomy to help identify nonequatorial orbits whose radial and polar frequencies are rationally related, or in resonance. The thesis culminates by describing how those resonant orbits can be leveraged for an order of magnitude or more reduction in the computational cost of adiabatic order EMRI trajectories, which are so prohibitively expensive that no such relativistically correct inspirals have been generated to date.
Gravitational wave science from space
NASA Astrophysics Data System (ADS)
Gair, Jonathan R.
2016-05-01
The rich millihertz gravitational wave band can only be accessed with a space- based detector. The technology for such a detector will be demonstrated by the LISA Pathfinder satellite that is due to launch this year and ESA has selected gravitational wave detection from space as the science theme to be addressed by the L3 large mission to be launched around 2034. In this article we will discuss the sources that such an instrument will observe, and how the numbers of events and precision of parameter determination are affected by modifications to the, as yet not finalised, mission design. We will also describe some of the exciting scientific applications of these observations, to astrophysics, fundamental physics and cosmology.
Quantum Emulation of Gravitational Waves
Fernandez-Corbaton, Ivan; Cirio, Mauro; Büse, Alexander; Lamata, Lucas; Solano, Enrique; Molina-Terriza, Gabriel
2015-01-01
Gravitational waves, as predicted by Einstein’s general relativity theory, appear as ripples in the fabric of spacetime traveling at the speed of light. We prove that the propagation of small amplitude gravitational waves in a curved spacetime is equivalent to the propagation of a subspace of electromagnetic states. We use this result to propose the use of entangled photons to emulate the evolution of gravitational waves in curved spacetimes by means of experimental electromagnetic setups featuring metamaterials. PMID:26169801
Gravitational wave emission from oscillating millisecond pulsars
NASA Astrophysics Data System (ADS)
Alford, Mark G.; Schwenzer, Kai
2015-02-01
Neutron stars undergoing r-mode oscillation emit gravitational radiation that might be detected on the Earth. For known millisecond pulsars the observed spin-down rate imposes an upper limit on the possible gravitational wave signal of these sources. Taking into account the physics of r-mode evolution, we show that only sources spinning at frequencies above a few hundred Hertz can be unstable to r-modes, and we derive a more stringent universal r-mode spin-down limit on their gravitational wave signal. We find that this refined bound limits the gravitational wave strain from millisecond pulsars to values below the detection sensitivity of next generation detectors. Young sources are therefore a more promising option for the detection of gravitational waves emitted by r-modes and to probe the interior composition of compact stars in the near future.
On the Unreasonable Effectiveness of post-Newtonian Theory in Gravitational-Wave Physics
Clifford M. Will
2016-07-12
The first indirect detection of gravitational waves involved a binary system of neutron stars.Â In the future, the first direct detection may also involve binary systems -- inspiralling and merging binary neutron stars or black holes. This means that it is essential to understand in full detail the two-body system in general relativity, a notoriously difficult problem with a long history. Post-Newtonian approximation methods are thought to work only under slow motion and weak field conditions, while numerical solutions of Einstein's equations are thought to be limited to the final merger phase.Â Recent results have shown that post-Newtonian approximations seem to remain unreasonably valid well into the relativistic regime, while advances in numerical relativity now permit solutions for numerous orbits before merger.Â It is now possible to envision linking post-Newtonian theory and numerical relativity to obtain a complete ``solution'' of the general relativistic two-body problem.Â These solutions will play a central role in detecting and understanding gravitational wave signals received by interferometric observatories on Earth and in space.
NASA Astrophysics Data System (ADS)
2016-09-01
A scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS), "On the first direct detection of gravitational waves," was held in the conference hall of the Lebedev Physical Institute, RAS on 2 March 2016. The papers collected in this issue were written based on talks given at the session: (1) Pustovoit V I (Scientific and Technological Center of Unique Instrumentation, Moscow) "On the direct detection of gravitational waves"; (2) Braginsky V B, Bilenko I A, Vyatchanin S P, Gorodetsky M L, Mitrofanov V P, Prokhorov L G, Strigin S E, Khalili F Ya (Lomonosov Moscow State University, Moscow) "The road to the discovery of gravitational waves"; (3) Khazanov E A (Institute of Applied Physics, RAS, Nizhny Novgorod) "Thermooptics of magnetoactive media: Faraday isolators for high average power lasers"; (4) Cherepashchuk A M (Sternberg Astronomical Institute, Lomonosov Moscow State University, Moscow) "Discovery of gravitational waves: a new chapter in black hole studies"; (5) Lipunov V M (Sternberg Astronomical Institute, Lomonosov Moscow State University, Moscow) "Astrophysical meaning of the discovery of gravitational waves." Papers based on talks 2-5 are published in this issue of the journal. A paper based on talk 1 will be published in a forthcoming issue of Physics-Uspekhi. Additional information on the discovery of gravitational waves, the history of their theoretical prediction, and the advances in possible methods for their investigation can be found on the Physics-Uspekhi site www.ufn.ru, on the page http://ufn.ru/en/events/gravitational_waves_discovery.html dedicated to this outstanding discovery. • The road to the discovery of gravitational waves, V B Braginsky, I A Bilenko, S P Vyatchanin, M L Gorodetskii, V P Mitrofanov, L G Prokhorov, S E Strigin, F Ya Khalili Physics-Uspekhi, 2016, Volume 59, Number 9, Pages 879-885 • Thermooptics of magnetoactive media: Faraday isolators for high average power lasers, E A Khazanov
NASA Astrophysics Data System (ADS)
Cokelaer, T.
2007-11-01
Matched filtering is used to search for gravitational waves emitted by inspiralling compact binaries in data from the ground-based interferometers. One of the key aspects of the detection process is the design of a template bank that covers the astrophysically pertinent parameter space. In an earlier paper, we described a template bank that is based on a square lattice. Although robust, we showed that the square placement is overefficient, with the implication that it is computationally more demanding than required. In this paper, we present a template bank based on an hexagonal lattice, which size is reduced by 40% with respect to the proposed square placement. We describe the practical aspects of the hexagonal template bank implementation, its size, and computational cost. We have also performed exhaustive simulations to characterize its efficiency and safeness. We show that the bank is adequate to search for a wide variety of binary systems (primordial black holes, neutron stars, and stellar-mass black holes) and in data from both current detectors (initial LIGO, Virgo and GEO600) as well as future detectors (advanced LIGO and EGO). Remarkably, although our template bank placement uses a metric arising from a particular template family, namely, stationary phase approximation, we show that it can be used successfully with other template families (e.g., Padé resummation and effective one-body approximation). This quality of being effective for different template families makes the proposed bank suitable for a search that would use several of them in parallel (e.g., in a binary black hole search). The hexagonal template bank described in this paper is currently used to search for nonspinning inspiralling compact binaries in data from the Laser Interferometer Gravitational-Wave Observatory (LIGO).
Hunting for dark particles with gravitational waves
Giudice, Gian F.; McCullough, Matthew; Urbano, Alfredo
2016-10-03
The LIGO observation of gravitational waves from a binary black hole merger has begun a new era in fundamental physics. If new dark sector particles, be they bosons or fermions, can coalesce into exotic compact objects (ECOs) of astronomical size, then the first evidence for such objects, and their underlying microphysical description, may arise in gravitational wave observations. In this work we study how the macroscopic properties of ECOs are related to their microscopic properties, such as dark particle mass and couplings. We then demonstrate the smoking gun exotic signatures that would provide observational evidence for ECOs, and hence new particles, in terrestrial gravitational wave observatories. Finally, we discuss how gravitational waves can test a core concept in general relativity: Hawking’s area theorem.
Building a Galactic Scale Gravitational Wave Observatory
NASA Astrophysics Data System (ADS)
McLaughlin, Maura
2016-03-01
Pulsars are rapidly rotating neutron stars with phenomenal rotational stability that can be used as celestial clocks in a variety of fundamental physics experiences. One of these experiments involves using a pulsar timing array of precisely timed millisecond pulsars to detect perturbations due to gravitational waves. The low frequency gravitational waves detectable through pulsar timing will most likely result from an ensemble of supermassive black hole binaries. I will introduce the efforts of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav), a collaboration that monitors over 50 millisecond pulsars with the Green Bank Telescope and the Arecibo Observatory, with a focus on our observation and data analysis methods. I will also describe how NANOGrav has joined international partners through the International Pulsar Timing Array to form a low-frequency gravitational wave detector of unprecedented sensitivity.
Hunting for dark particles with gravitational waves
NASA Astrophysics Data System (ADS)
Giudice, Gian F.; McCullough, Matthew; Urbano, Alfredo
2016-10-01
The LIGO observation of gravitational waves from a binary black hole merger has begun a new era in fundamental physics. If new dark sector particles, be they bosons or fermions, can coalesce into exotic compact objects (ECOs) of astronomical size, then the first evidence for such objects, and their underlying microphysical description, may arise in gravitational wave observations. In this work we study how the macroscopic properties of ECOs are related to their microscopic properties, such as dark particle mass and couplings. We then demonstrate the smoking gun exotic signatures that would provide observational evidence for ECOs, and hence new particles, in terrestrial gravitational wave observatories. Finally, we discuss how gravitational waves can test a core concept in general relativity: Hawking's area theorem.
Probing cosmic superstrings with gravitational waves
NASA Astrophysics Data System (ADS)
Sousa, L.; Avelino, P. P.
2016-09-01
We compute the stochastic gravitational wave background generated by cosmic superstrings using a semianalytical velocity-dependent model to describe their dynamics. We show that heavier string types may leave distinctive signatures on the stochastic gravitational wave background spectrum within the reach of present and upcoming gravitational wave detectors. We examine the physically motivated scenario in which the physical size of loops is determined by the gravitational backreaction scale and use NANOGrav data to derive a conservative constraint of G μF<3.2 ×10-9 on the tension of fundamental strings. We demonstrate that approximating the gravitational wave spectrum generated by cosmic superstring networks using the spectrum generated by ordinary cosmic strings with reduced intercommuting probability (which is often done in the literature) leads, in general, to weaker observational constraints on G μF. We show that the inclusion of heavier string types is required for a more accurate characterization of the region of the (gs,G μF) parameter space that may be probed using direct gravitational wave detectors. In particular, we consider the observational constraints that result from NANOGrav data and show that heavier strings generate a secondary exclusion region of parameter space.
NASA Astrophysics Data System (ADS)
Taylor, Stephen; Sampson, Laura; Simon, Joseph
2016-03-01
There has recently been significant interest in how the galactic environments of supermassive black-hole binaries influences the stochastic gravitational-wave background signal from a population of these systems, and in how the resulting detection prospects for pulsar-timing arrays are effected. Tackling these problems requires us to have robust and computationally-efficient models for the strain spectrum as a function of different environment influences or the binary orbital eccentricity. In this talk we describe a new method of constructing these models from a small number of synthesized black-hole binary populations which have varying input physics. We use these populations to train an interpolant via Gaussian-process regression, allowing us to carry real physics into our subsequent pulsar-timing array inferences, and to also correctly propagate forward uncertainties from our interpolation.
Gravitational Waves From Supermassive Black Holes
NASA Astrophysics Data System (ADS)
di Girolamo, Tristano
2016-10-01
In this talk, I will present the first direct detections of gravitational waves from binary stellar-mass black hole mergers during the first observing run of the two detectors of the Advanced Laser Interferometer Gravitational-wave Observatory, which opened the field of gravitational-wave astronomy, and then discuss prospects for observing gravitational waves from supermassive black holes with future detectors.
Astrophysical meaning of the discovery of gravitational waves
NASA Astrophysics Data System (ADS)
Lipunov, V. M.
2016-09-01
The discovery of gravitational waves by the international collaboration LIGO (Laser Interferometer Gravitational-Wave Observatory)/Virgo on the one hand is a triumphant confirmation of the general theory of relativity, and on the other confirms the general fundamental ideas on the nuclear evolution of baryon matter in the Universe concentrated in binary stars. LIGO/Virgo may turn out to be the first experiment in the history of physics to detect two physical entities, gravitational waves and black holes.
Orientational atom interferometers sensitive to gravitational waves
Lorek, Dennis; Laemmerzahl, Claus; Wicht, Andreas
2010-02-15
We present an atom interferometer that differs from common atom interferometers as it is not based on the spatial splitting of electronic wave functions, but on orienting atoms in space. As an example we present how an orientational atom interferometer based on highly charged hydrogen-like atoms is affected by gravitational waves. We show that a monochromatic gravitational wave will cause a frequency shift that scales with the binding energy of the system rather than with its physical dimension. For a gravitational wave amplitude of h=10{sup -23} the frequency shift is of the order of 110 {mu}Hz for an atom interferometer based on a 91-fold charged uranium ion. A frequency difference of this size can be resolved by current atom interferometers in 1 s.
Gravitational Physics Research
NASA Technical Reports Server (NTRS)
Wu, S. T.
2000-01-01
Gravitational physics research at ISPAE is connected with NASA's Relativity Mission (Gravity Probe B (GP-B)) which will perform a test of Einstein's General Relativity Theory. GP-B will measure the geodetic and motional effect predicted by General Relativity Theory with extremely stable and sensitive gyroscopes in an earth orbiting satellite. Both effects cause a very small precession of the gyroscope spin axis. The goal of the GP-B experiment is the measurement of the gyroscope precession with very high precision. GP-B is being developed by a team at Stanford University and is scheduled for launch in the year 2001. The related UAH research is a collaboration with Stanford University and MSFC. This research is focussed primarily on the error analysis and data reduction methods of the experiment but includes other topics concerned with experiment systems and their performance affecting the science measurements. The hydrogen maser is the most accurate and stable clock available. It will be used in future gravitational physics missions to measure relativistic effects such as the second order Doppler effect. The HMC experiment, currently under development at the Smithsonian Astrophysical Observatory (SAO), will test the performance and capability of the hydrogen maser clock for gravitational physics measurements. UAH in collaboration with the SAO science team will study methods to evaluate the behavior and performance of the HMC. The GP-B data analysis developed by the Stanford group involves complicated mathematical operations. This situation led to the idea to investigate alternate and possibly simpler mathematical procedures to extract the GP-B measurements form the data stream. Comparison of different methods would increase the confidence in the selected scheme.
LISA in the gravitational wave decade
NASA Astrophysics Data System (ADS)
Conklin, John; Cornish, Neil
2015-04-01
With the expected direct detection of gravitational waves in the second half of this decade by Advanced LIGO and pulsar timing arrays, and with the launch of LISA Pathfinder in the summer of this year, this can arguably be called the decade of gravitational waves. Low frequency gravitational waves in the mHz range, which can only be observed from space, provide the richest science and complement high frequency observatories on the ground. A space-based observatory will improve our understanding of the formation and growth of massive black holes, create a census of compact binary systems in the Milky Way, test general relativity in extreme conditions, and enable searches for new physics. LISA, by far the most mature concept for detecting gravitational waves from space, has consistently ranked among the nation's top priority large science missions. In 2013, ESA selected the science theme ``The Gravitational Universe'' for its third large mission, L3, under the Cosmic Visions Program, with a planned launch date of 2034. Recently, NASA has decided to join with ESA on the L3 mission as a junior partner. Both agencies formed a committee to advise them on the scientific and technological approaches for a space based gravitational wave observatory. The leading mission design, Evolved LISA or eLISA, is a slightly de-scoped version of the earlier LISA design. This talk will describe activities of the Gravitational Wave Science Interest Group (GWSIG) under the Physics of the Cosmos Program Analysis Group (PhysPAG), focusing on LISA technology development in both the U.S. and Europe, including the LISA Pathfinder mission.
GRAVITATIONAL WAVES FROM STELLAR COLLAPSE
C. L. FRYER
2001-01-01
Stellar core-collapse plays an important role in nearly all facets of astronomy: cosmology (as standard candles), formation of compact objects, nucleosynthesis and energy deposition in galaxies. In addition, they release energy in powerful explosions of light over a range of energies, neutrinos, and the subject of this meeting, gravitational waves. Because of this broad range of importance, astronomers have discovered a number of constraints which can be used to help them understand the importance of stellar core-collapse as gravitational wave sources.
Gravitational waves and multimessenger astronomy
NASA Astrophysics Data System (ADS)
Ricci, Fulvio
2016-07-01
It is widely expected that in the coming quinquennium the first gravitational wave signal will be directly detected. The ground-based advanced LIGO and Virgo detectors are being upgraded to a sensitivity level such that we expect to be measure a significant binary merger rate. Gravitational waves events are likely to be accompanied by electromagnetic counterparts and neutrino emission carrying complementary information to those associated to the gravitational signals. If it becomes possible to measure all these forms of radiation in concert, we will end up an impressive increase in the comprehension of the whole phenomenon. In the following we summarize the scientific outcome of the interferometric detectors in the past configuration. Then we focus on some of the potentialities of the advanced detectors once used in the new context of the multimessenger astronomy.
Merging Black Holes and Gravitational Waves
NASA Technical Reports Server (NTRS)
Centrella, Joan
2009-01-01
This talk will focus on simulations of binary black hole mergers and the gravitational wave signals they produce. Applications to gravitational wave detection with LISA, and electronagnetic counterparts, will be highlighted.
Gravitational Wave Astrophysics: Opening the New Frontier
NASA Technical Reports Server (NTRS)
Centrella, Joan
2011-01-01
The gravitational wave window onto the universe is expected to open in 5 years, when ground-based detectors make the first detections in the high-frequency regime. Gravitational waves are ripples in spacetime produced by the motions of massive objects such as black holes and neutron stars. Since the universe is nearly transparent to gravitational waves, these signals carry direct information about their sources such as masses, spins, luminosity distances, and orbital parameters through dense, obscured regions across cosmic time. This article explores gravitational waves as cosmic messengers, highlighting key sources, detection methods, and the astrophysical payoffs across the gravitational wave spectrum. Keywords: Gravitational wave astrophysics; gravitational radiation; gravitational wave detectors; black holes.
Gravitational Wave Astrophysics: Opening the New Frontier
NASA Technical Reports Server (NTRS)
Centrella, Joan
2011-01-01
The gravitational wave window onto the universe is expected to open in approximately 5 years, when ground-based detectors make the first detections in the high-frequency regime. Gravitational waves are ripples in spacetime produced by the motions of massive objects such as black holes and neutron stars. Since the universe is nearly transparent to gravitational waves, these signals carry direct information about their sources - such as masses, spins, luminosity distances, and orbital parameters through dense, obscured regions across cosmic time. This talk will explore gravitational waves as cosmic messengers, highlighting key sources, detection methods, and the astrophysical payoffs across the gravitational wave spectrum.
Gravitational Wave Astrophysics: Opening the New Frontier
NASA Technical Reports Server (NTRS)
Centrella, Joan
2011-01-01
The gravitational wave window onto the universe is expected to open in approx. 5 years, when ground-based detectors make the first detections in the high-frequency regime. Gravitational waves are ripples in spacetime produced by the motions of massive objects such as black holes and neutron stars. Since the universe is nearly transparent to gravitational waves, these signals carry direct information about their sources - such as masses, spins, luminosity distances, and orbital parameters, through dense, obscured regions across cosmic time. This article explores gravitational waves as cosmic messengers, highlighting key sources, detection methods, and the astrophysical payoffs across the gravitational wave spectrum.
Electromagnetic Counterparts to Gravitational Waves
NASA Astrophysics Data System (ADS)
Kasliwal, Mansi M.; GROWTH Collaboration; iPTF/ZTF Collaboration
2017-01-01
The direct detection of gravitational waves from merging black holes marks the dawn of a new era. I will present ongoing efforts and prospectsto identify and characterize the electromagnetic counterpart. Among the various models for electromagnetic emission from binary neutronstar mergers, free neutron decay gives the most luminous and fast-evolving optical counterpart. I will describe a co-ordinated global effort, the GROWTH (Global Relay of Observatories Watching Transients Happen) network working in tandem with the Zwicky Transient Facility.
Liu Jinzhong; Han Zhanwen; Zhang Fenghui; Zhang Yu
2010-08-20
Close double white dwarfs (CDWDs) are believed to dominate the Galactic gravitational wave (GW) radiation in the frequency range 10{sup -4} to 0.1 Hz, which will be detected by the Laser Interferometer Space Antenna (LISA) detector. The aim of this detector is to detect GW radiation from astrophysical sources in the universe and to help improve our understanding of the origin of the sources and their physical properties (masses and orbital periods). In this paper, we study the probable candidate sources in the Galaxy for the LISA detector: CDWDs. We use the binary population synthesis approach of CDWDs together with the latest findings of the synthesis models from Han, who proposed three evolutionary channels: (1) stable Roche lobe overflow plus common envelope (RLOF+CE), (2) CE+CE, and (3) exposed core plus CE. As a result, we systematically investigate the detailed physical properties (the distributions of masses, orbital periods, and chirp masses) of the CDWD sources for the LISA detector, examine the importance of the three evolutionary channels for the formation of CDWDs, and carry out Monte Carlo simulations. Our results show that RLOF+CE and CE+CE are the main evolutionary scenarios leading to the formation of CDWDs. For the LISA detectable sources, we also explore and discuss the importance of these three evolutionary channels. Using the calculated birth rate, we compare our results to the LISA sensitivity curve and the foreground noise floor of CDWDs. We find that our estimate for the number of CDWD sources that can be detected by the LISA detector is greater than 10,000. We also find that the detectable CDWDs are produced via the CE+CE channel and we analyze the fraction of the detectable CDWDs that are double helium (He+He), or carbon-oxygen plus helium (CO+He) WD binary systems.
Low frequency gravitational wave astrophysics
NASA Astrophysics Data System (ADS)
Larson, Shane
The field of low-frequency gravitational wave astronomy is evolving as the design of the Laser Interferometer Space Antenna (LISA) is in flux. Changing mission architectures naturally has an impact on the science goals and science capabilities in gravitational wave astronomy, requiring astrophysicists to pursue a deeper understanding on three fronts. (1) What astrophysical knowledge can be extracted from populations of sources based on their relative strengths in the data streams? (2) How are the science returns maximized as detector capabilities evolve? (3) How do evolving detector performance expectations alter the science that is possible with space- based gravitational wave detectors? This work proposes a series of investigations that address these questions along two broad avenues of inquiry. The first thrust of this effort is designed to examine how the population of ultra-compact galactic binaries can be better characterized by multi-messenger observations and statistical population analyses. While these investigations are astrophysical interesting in and of themselves, they are particularly relevant as detector designs evolve because the binaries are a limiting source of astrophysical noise that must be mitigated in order to maximize the science return for other sources, such as massive binary black hole inspirals and extreme mass ratio inspirals. The second thrust of this effort is geared toward characterization of the detector itself, since this ultimately fixes our ability to answer astrophysical questions. While many high-fidelity simulators exist for the original LISA mission architecture, the work proposed here will develop a new, flexible suite of prototyping tools analogous to the "Online Sensitivity Curve Generator" (which the PI authored). These tools will allow astrophysicists and data analysts alike to rapidly assess whether new proposed architectures for a space-based gravitational wave observatory will enhance or adversely impact the science
Gravitational wave production at the end of inflation.
Easther, Richard; Giblin, John T; Lim, Eugene A
2007-11-30
We consider gravitational wave production due to parametric resonance at the end of inflation, or "preheating." This leads to large inhomogeneities that source a stochastic background of gravitational waves at scales inside the comoving Hubble horizon at the end of inflation. We confirm that the present amplitude of these gravitational waves need not depend on the inflationary energy scale. We analyze an explicit model where the inflationary energy scale is approximately 10{9} GeV, yielding a signal close to the sensitivity of Advanced Laser Interferometer Gravitational Wave Observatory and Big Bang Observer. This signal highlights the possibility of a new observational "window" into inflationary physics and provides significant motivation for searches for stochastic backgrounds of gravitational waves in the Hz to GHz range, with an amplitude on the order of Omega_{gw}(k)h{2} approximately 10{-11}.
Listening to the Universe with gravitational waves
NASA Astrophysics Data System (ADS)
Sathyaprakash, B. S.
2016-07-01
The discovery of gravitational waves by the twin LIGO detectors in September 2015 has opened a new window for observational astronomy. The coming years will witness the emergence of other detectors such as Advanced Virgo, KAGRA and LIGO-India. The worldwide network of these detectors will not only observe binary black holes, which we now know will be the dominant sources, but other sources such as binary neutron stars, neutron star-black hole binaries, supernovae, stochastic backgrounds and unknown sources that we do not know yet. In my talk I will describe how gravitational wave observations will help us gain deeper insights into fundamental physics, astrophysics and cosmology in the coming years and decades.
Extragalactic sources of gravitational waves
NASA Astrophysics Data System (ADS)
Rees, M. J.
The prospects of detecting gravitational waves from galactic nuclei are shown to be bleak: although some 'scenarios', such as those involving black hole coalescence, would emit a pulse with about 0.1 efficiency, the predicted event rate is discouragingly low. If most of the 'unseen' mass in the universe were in the remnants of massive 'Population III' stars, then the overlapping bursts from the collapse of such objects in early epochs would yield a stochastic background that could amount to about 0.001 (or even more) of the critical cosmological density. Such a background may be above the detectability threshold for future experiments, and can be probed by studying the timing noise of pulsars, and the secular behavior of the binary pulsar. General constraints on stochastic backgrounds, including 'primordial' gravitational radiation, are summarized.
Electromagnetic Counterparts of Gravitational Wave Transients
NASA Astrophysics Data System (ADS)
Branchesi, Marica
2015-03-01
In the near future the ground-based gravitational wave detectors will reach sensitivities that should make it possible for the first time to directly observe gravitational waves. The simultaneous availability of gravitational wave detectors observing together with space and ground-based electromagnetic telescopes will offer a great opportunity to explore the Universe in a new multi-messenger perspective. Promising sources of gravitational waves are the most energetic astrophysical events such as the merger of neutron stars and/or stellar-mass black holes and the core collapse of massive stars. These events are believed to produce electromagnetic transients in the sky, like gamma-ray bursts and supernovae. An overview of the expected electromagnetic counterparts of the gravitational wave sources is presented, focusing on the challenges, opportunities and strategies for starting transient gravitational wave astronomy.
Singularities from colliding plane gravitational waves
NASA Astrophysics Data System (ADS)
Tipler, Frank J.
1980-12-01
A simple geometrical argument is given which shows that a collision between two plane gravitational waves must result in singularities. The argument suggests that these singularities are a peculiar feature of plane waves, because singularities are also a consequence of a collision between self-gravitating plane waves of other fields with arbitrarily small energy density.
Gravitational Waves: Elusive Cosmic Messengers
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes is expected to be the strongest g ravitational wave source for ground-based interferometers such as LIG O, VIRGO, and GE0600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires t hat we know the radiation waveforms they emit. Since these mergers ta ke place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate t hese waveforms. For more than 30 years, scientists have tried to comp ute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could comple te even a single orbit. Within the past few years, however, this situ ation has changed dramatically, with a series of remarkable breakthro ughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applic ations in gravitational wave detection, data analysis, and astrophysi cs.
Multimessenger time delays from lensed gravitational waves
NASA Astrophysics Data System (ADS)
Baker, Tessa; Trodden, Mark
2017-03-01
We investigate the potential of high-energy astrophysical events, from which both massless and massive signals are detected, to probe fundamental physics. In particular, we consider how strong gravitational lensing can induce time delays in multimessenger signals from the same source. Obvious messenger examples are massless photons and gravitational waves, and massive neutrinos, although more exotic applications can also be imagined, such as to massive gravitons or axions. The different propagation times of the massive and massless particles can, in principle, place bounds on the total neutrino mass and probe cosmological parameters. Whilst measuring such an effect may pose a significant experimental challenge, we believe that the "massive time delay" represents an unexplored fundamental physics phenomenon.
Gravitational Wave Astrophysics: Opening the New Frontier
NASA Technical Reports Server (NTRS)
Centrella, Joan
2011-01-01
A new era in astronomy will begin when the gravitational wave window onto the universe opens in approx. 5 years) as ground-based detectors make the first detections in the high-frequency regime. Since the universe is nearly transparent to gravitational waves) these signals carry direct information about their sources - such as masses) spins) luminosity distances) and orbital parameters - through dense) obscured regions across cosmic time. This talk will explore gravitational waves as cosmic messengers) highlighting key sources and opportunities for multi-messenger astronomy across the gravitational wave spectrum.
Gravitational Wave Astrophysics: Opening the New Frontier
NASA Technical Reports Server (NTRS)
Centrella, Joan
2011-01-01
A new era in time-domain astronomy will begin when the gravitational wave window onto the universe opens in approx. 5 years, as ground-based detectors make the first detections in the high-frequency regime. Since the universe is nearly transparent to gravitational waves, these signals carry direct information about their sources - such as masses, spins, luminosity distances, and orbital parameters through dense, obscured regions across cosmic time. This talk will explore gravitational waves as cosmic messengers, highlighting key sources and opportunities for multimessenger astronomy across the gravitational wave spectrum.
Gravitational Wave Astrophysics: Opening the New Frontier
NASA Technical Reports Server (NTRS)
Centrella, Joan
2012-01-01
A new era in astronomy will begin when the gravitational wave window onto the universe opens in approx. 5 years, as ground-based detectors make the first detections in the high-frequency regime. Since the universe is nearly transparent to gravitational waves, these signals carry direct information about their sources - such as masses, spins, luminosity distances, and orbital parameters - through dense, obscured regions across cosmic time. This talk will explore gravitational waves as cosmic messengers, highlighting key sources and opportunities for multi-messenger astronomy across the gravitational wave spectrum.
Spacetime Symphony: APOD and Gravitational Waves
NASA Astrophysics Data System (ADS)
Cominsky, Lynn R.; Simonnet, Aurore; LIGO-Virgo Scientific Collaboration
2017-01-01
In 1915, Albert Einstein published his General Theory of Relativity. In this theory, gravity is not a force, but a property of space and time in the presence of massive objects. A century later, on September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) received the first confirmed gravitational wave signals. Now known as GW150914, the event represents the coalescence of two distant black holes that were previously in mutual orbit. The LIGO-Virgo Scientific Collaboration planned a detailed social media strategy to publicize the February 11, 2016 press conference that announced this discovery. Astronomy Picture of the Day (APOD) was a major factor in disseminating the now iconic imagery that was developed, and the LVC worked closely with APOD to ensure that the secrecy would be maintained throughout the press embargo period. Due to the success of our efforts, we repeated the process for the AAS press conference that announced GW151226, the second confirmed gravitational wave event. We have also repurposed the APOD imagery for an online course for community college instructors, as well as in a poster that will be available through CPEPphysics.org (Contemporary Physics Education Project).
Gravitational waves from axion monodromy
NASA Astrophysics Data System (ADS)
Hebecker, Arthur; Jaeckel, Joerg; Rompineve, Fabrizio; Witkowski, Lukas T.
2016-11-01
Large field inflation is arguably the simplest and most natural variant of slow-roll inflation. Axion monodromy may be the most promising framework for realising this scenario. As one of its defining features, the long-range polynomial potential possesses short-range, instantonic modulations. These can give rise to a series of local minima in the post-inflationary region of the potential. We show that for certain parameter choices the inflaton populates more than one of these vacua inside a single Hubble patch. This corresponds to a dynamical phase decomposition, analogously to what happens in the course of thermal first-order phase transitions. In the subsequent process of bubble wall collisions, the lowest-lying axionic minimum eventually takes over all space. Our main result is that this violent process sources gravitational waves, very much like in the case of a first-order phase transition. We compute the energy density and peak frequency of the signal, which can lie anywhere in the mHz-GHz range, possibly within reach of next-generation interferometers. We also note that this ``dynamical phase decomposition" phenomenon and its gravitational wave signal are more general and may apply to other inflationary or reheating scenarios with axions and modulated potentials.
Gravitational waves in bimetric MOND
NASA Astrophysics Data System (ADS)
Milgrom, Mordehai
2014-01-01
I consider the weak-field limit (WFL) of the bimetric, relativistic formulation of the modified Newtonian dynamics (BIMOND)—the lowest order in the small departures hμν=gμν-ημν, h stretchy="false">^μν=g stretchy="false">^μν-ημν from double Minkowski space-time. In particular, I look at propagating solutions, for a favorite subclass of BIMOND. The WFL splits into two sectors for two linear combinations, hμν±, of hμν and h stretchy="false">^μν. The hμν+ sector is equivalent to the WFL of general relativity (GR), with its gauge freedom, and has the same vacuum gravitational waves. The hμν- sector is fully nonlinear even for the weakest hμν-, and inherits none of the coordinate gauge freedom. The equations of motion are scale invariant in the deep-MOND limit of purely gravitational systems. In these last two regards, the BIMOND WFL is greatly different from that of other bimetric theories studied to date. Despite the strong nonlinearity, an arbitrary pair of harmonic GR wave packets of hμν and h stretchy="false">^μν moving in the same direction, is a solution of the (vacuum) BIMOND WFL.
Gravitational waves from axion monodromy
Hebecker, Arthur; Jaeckel, Joerg; Rompineve, Fabrizio; Witkowski, Lukas T.
2016-11-02
Large field inflation is arguably the simplest and most natural variant of slow-roll inflation. Axion monodromy may be the most promising framework for realising this scenario. As one of its defining features, the long-range polynomial potential possesses short-range, instantonic modulations. These can give rise to a series of local minima in the post-inflationary region of the potential. We show that for certain parameter choices the inflaton populates more than one of these vacua inside a single Hubble patch. This corresponds to a dynamical phase decomposition, analogously to what happens in the course of thermal first-order phase transitions. In the subsequent process of bubble wall collisions, the lowest-lying axionic minimum eventually takes over all space. Our main result is that this violent process sources gravitational waves, very much like in the case of a first-order phase transition. We compute the energy density and peak frequency of the signal, which can lie anywhere in the mHz-GHz range, possibly within reach of next-generation interferometers. We also note that this “dynamical phase decomposition' phenomenon and its gravitational wave signal are more general and may apply to other inflationary or reheating scenarios with axions and modulated potentials.
Atomic gravitational wave interferometric sensor
Dimopoulos, Savas; Hogan, Jason M.; Kasevich, Mark A.; Graham, Peter W.; Rajendran, Surjeet
2008-12-15
We propose two distinct atom interferometer gravitational wave detectors, one terrestrial and another satellite based, utilizing the core technology of the Stanford 10 m atom interferometer presently under construction. Each configuration compares two widely separated atom interferometers run using common lasers. The signal scales with the distance between the interferometers, which can be large since only the light travels over this distance, not the atoms. The terrestrial experiment with two {approx}10 m atom interferometers separated by a {approx}1 km baseline can operate with strain sensitivity {approx}(10{sup -19}/{radical}(Hz)) in the 1 Hz-10 Hz band, inaccessible to LIGO, and can detect gravitational waves from solar mass binaries out to megaparsec distances. The satellite experiment with two atom interferometers separated by a {approx}1000 km baseline can probe the same frequency spectrum as LISA with comparable strain sensitivity {approx}(10{sup -20}/{radical}(Hz)). The use of ballistic atoms (instead of mirrors) as inertial test masses improves systematics coming from vibrations and acceleration noise, and significantly reduces spacecraft control requirements. We analyze the backgrounds in this configuration and discuss methods for controlling them to the required levels.
Gravitational wave-Gauge field oscillations
NASA Astrophysics Data System (ADS)
Caldwell, R. R.; Devulder, C.; Maksimova, N. A.
2016-09-01
Gravitational waves propagating through a stationary gauge field transform into gauge field waves and back again. When multiple families of flavor-space locked gauge fields are present, the gravitational and gauge field waves exhibit novel dynamics. At high frequencies, the system behaves like coupled oscillators in which the gravitational wave is the central pacemaker. Due to energy conservation and exchange among the oscillators, the wave amplitudes lie on a multidimensional sphere, reminiscent of neutrino flavor oscillations. This phenomenon has implications for cosmological scenarios based on flavor-space locked gauge fields.
Gravitational Wave Astronomy:The High Frequency Window
NASA Astrophysics Data System (ADS)
Andersson, Nils; Kokkotas, Kostas D.
As several large scale interferometers are beginning to take data at sensitivities where astrophysical sources are predicted, the direct detection of gravitational waves may well be imminent. This would (finally) open the long anticipated gravitational-wave window to our Universe, and should lead to a much improved understanding of the most violent processes imaginable; the formation of black holes and neutron stars following core collapse supernovae and the merger of compact objects at the end of binary inspiral. Over the next decade we can hope to learn much about the extreme physics associated with, in particular, neutron stars. This contribution is divided in two parts. The first part provides a text-book level introduction to gravitational radiation. The key concepts required for a discussion of gravitational-wave physics are introduced. In particular, the quadrupole formula is applied to the anticipated bread-and-butter source for detectors like LIGO, GEO600, EGO and TAMA300: inspiralling compact binaries. The second part provides a brief review of high frequency gravitational waves. In the frequency range above (say) 100 Hz, gravitational collapse, rotational instabilities and oscillations of the remnant compact objects are potentially important sources of gravitational waves. Significant and unique information concerning the various stages of collapse, the evolution of protoneutron stars and the details of the supranuclear equation of state of such objects can be drawn from careful study of the gravitational-wave signal. As the amount of exciting physics one may be able to study via the detections of gravitational waves from these sources is truly inspiring, there is strong motivation for the development of future generations of ground based detectors sensitive in the range from hundreds of Hz to several kHz.
An heuristic introduction to gravitational waves
NASA Astrophysics Data System (ADS)
Sandberg, Vernon D.
1983-03-01
We describe in physical terms the phenomenon of gravitational waves. The philosophy of William Gilbert is used.1 ``Since in the discovery of secret things and in the investigation of hidden causes, stronger reasons are obtained from sure experiments and demonstrated arguments than from probable conjectures and the opinions of philosophical speculators of the common sort; therefore to the end that the noble substance of that great loadstone, our common mother (the earth), still quite unknown, and also the forces extraordinary and exalted of this globe may the better be understood...''
Sharing the Wonder of Gravitational Waves
NASA Astrophysics Data System (ADS)
Key, Joey Shapiro; LIGO Scientific Collaboration; Virgo Collaboration
2017-01-01
To share as widely as possible the excitement of the new discovery of gravitational waves, scientists in the LIGO Scientific Collaboration (LSC) and Virgo Collaboration prepared communication tools for a worldwide and diverse audience. This work included resources for traditional and social media outlets, preparing to engage at a wide range of levels and interests. The response to the LIGO discovery announcement indicated that the public is eager to engage with frontier physics. The LSC and Virgo outreach efforts hold lessons for broad STEM outreach including examples of citizen science initiatives and art +science collaboration as a way to inspire and engage a wide range of audiences.
Gravitational-wave Mission Study
NASA Technical Reports Server (NTRS)
Mcnamara, Paul; Jennrich, Oliver; Stebbins, Robin T.
2014-01-01
In November 2013, ESA selected the science theme, the "Gravitational Universe," for its third large mission opportunity, known as L3, under its Cosmic Vision Programme. The planned launch date is 2034. ESA is considering a 20% participation by an international partner, and NASA's Astrophysics Division has indicated an interest in participating. We have studied the design consequences of a NASA contribution, evaluated the science benefits and identified the technology requirements for hardware that could be delivered by NASA. The European community proposed a strawman mission concept, called eLISA, having two measurement arms, derived from the well studied LISA (Laser Interferometer Space Antenna) concept. The US community is promoting a mission concept known as SGO Mid (Space-based Gravitational-wave Observatory Mid-sized), a three arm LISA-like concept. If NASA were to partner with ESA, the eLISA concept could be transformed to SGO Mid by the addition of a third arm, augmenting science, reducing risk and reducing non-recurring engineering costs. The characteristics of the mission concepts and the relative science performance of eLISA, SGO Mid and LISA are described. Note that all results are based on models, methods and assumptions used in NASA studies
Folding gravitational-wave interferometers
NASA Astrophysics Data System (ADS)
Sanders, J. R.; Ballmer, Stefan W.
2017-01-01
The sensitivity of kilometer-scale terrestrial gravitational wave interferometers is limited by mirror coating thermal noise. Alternative interferometer topologies can mitigate the impact of thermal noise on interferometer noise curves. In this work, we explore the impact of introducing a single folding mirror into the arm cavities of dual-recycled Fabry–Perot interferometers. While simple folding alone does not reduce the mirror coating thermal noise, it makes the folding mirror the critical mirror, opening up a variety of design and upgrade options. Improvements to the folding mirror thermal noise through crystalline coatings or cryogenic cooling can increase interferometer range by as much as a factor of two over the Advanced LIGO reference design.
The Bright Future of Gravitational Wave Astronomy
NASA Astrophysics Data System (ADS)
Gonzalez, Gabriela
2008-04-01
These are exciting times in the search for gravitational waves. Gravitational waves are expected from many different astrophysical sources: brief transients from violent events like supernova explosions and collisions of neutron stars and black holes, coalescence of compact binary systems, continuous waves from rotating systems, and stochastic signals from cosmological origin or unresolved transients. The LIGO gravitational wave detectors have achieved unprecedented sensitivity to gravitational waves, and other detectors around the world are expected to reach similar sensitivities. The LIGO Scientific Collaboration (LSC) has recently completed their most sensitive observation run to date with LIGO and GEO detectors, including several months of joint observations with the European VIRGO detector. The LIGO Laboratory and the LSC, as well as the Virgo Collaboration, are actively preparing for operating enhanced detectors in the very near future. The next decade will see the construction and commissioning of Advanced LIGO and VIRGO, and quite possibly the launch of the space-based LISA mission, starting for sure then, if not earlier, a new era for gravitational wave astronomy. Plans for a world-wide network of ground based detectors involving more detectors in Europe, Japan and Australia are becoming more concrete. The future of gravitational wave astronomy is bright indeed! In this talk, will briefly describe the present status of the ground and space based detector projects and discuss the science we may expect to do with the detectors (and detections!) we will have in the upcoming era of gravitational wave astronomy.
Pulsar timing arrays: closing in on low- frequency gravitational waves
NASA Astrophysics Data System (ADS)
Sampson, Laura
2017-01-01
Just like electromagnetic radiation, gravitational waves come in a wide spectrum of frequencies. Different frequencies give us access to different physical information about our universe. By taking advantage of the phenomenal stability of the spin rate of millisecond pulsars, pulsar timing arrays will allow us to detect gravitational waves in the nanohertz band. The most likely source in this band is supermassive black hole binaries, formed when galaxies merge, and so the detection of these gravitational waves gives us a new tool to learn about the merger history of galaxies and the environment in galactic cores. I will discuss the exciting astrophysics we can learn using pulsar timing arrays, as well as the prospects and expected timeline for gravitational wave detection in this new frequency regime.
Gravitational Wave Detection in the Introductory Lab
NASA Astrophysics Data System (ADS)
Burko, Lior M.
2017-01-01
Great physics breakthroughs are rarely included in the introductory physics course. General relativity and binary black hole coalescence are no different, and can be included in the introductory course only in a very limited sense. However, we can design activities that directly involve the detection of GW150914, the designation of the Gravitation Wave signal detected on September 14, 2015, thereby engage the students in this exciting discovery directly. The activities naturally do not include the construction of a detector or the detection of gravitational waves. Instead, we design it to include analysis of the data from GW150914, which includes some interesting analysis activities for students of the introductory course. The same activities can be assigned either as a laboratory exercise or as a computational project for the same population of students. The analysis tools used here are simple and available to the intended student population. It does not include the sophisticated analysis tools, which were used by LIGO to carefully analyze the detected signal. However, these simple tools are sufficient to allow the student to get important results. We have successfully assigned this lab project for students of the introductory course with calculus at Georgia Gwinnett College.
Binary Black Holes and Gravitational Waves
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LIGO and LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these wave patterns.
Gravitational waves from neutron star binaries
NASA Astrophysics Data System (ADS)
Lee, Chang-Hwan
With H. A. Bethe, G. E. Brown worked on the merger rate of neutron star binaries for the gravitational wave detection. Their prediction has to be modified significantly due to the observations of 2M⊙ neutron stars and the detection of gravitational waves. There still, however, remains a possibility that neutron star-low mass black hole binaries are significant sources of gravitational waves for the ground-based detectors. In this paper, I review the evolution of neutron star binaries with super-Eddington accretion and discuss the future prospect.
Gravitational wave detection in space
NASA Astrophysics Data System (ADS)
Ni, Wei-Tou
Gravitational Wave (GW) detection in space is aimed at low frequency band (100nHz-100mHz) and middle frequency band (100mHz-10Hz). The science goals are the detection of GWs from (i) Supermassive Black Holes; (ii) Extreme-Mass-Ratio Black Hole Inspirals; (iii) Intermediate-Mass Black Holes; (iv) Galactic Compact Binaries and (v) Relic GW Background. In this paper, we present an overview on the sensitivity, orbit design, basic orbit configuration, angular resolution, orbit optimization, deployment, time-delay interferometry (TDI) and payload concept of the current proposed GW detectors in space under study. The detector proposals under study have arm length ranging from 1000km to 1.3 × 109km (8.6AU) including (a) Solar orbiting detectors — (ASTROD Astrodynamical Space Test of Relativity using Optical Devices (ASTROD-GW) optimized for GW detection), Big Bang Observer (BBO), DECi-hertz Interferometer GW Observatory (DECIGO), evolved LISA (e-LISA), Laser Interferometer Space Antenna (LISA), other LISA-type detectors such as ALIA, TAIJI etc. (in Earthlike solar orbits), and Super-ASTROD (in Jupiterlike solar orbits); and (b) Earth orbiting detectors — ASTROD-EM/LAGRANGE, GADFLI/GEOGRAWI/g-LISA, OMEGA and TIANQIN.
Gravitational Waves from Oscillons after Inflation
NASA Astrophysics Data System (ADS)
Antusch, Stefan; Cefalà, Francesco; Orani, Stefano
2017-01-01
We investigate the production of gravitational waves during preheating after inflation in the common case of field potentials that are asymmetric around the minimum. In particular, we study the impact of oscillons, comparatively long lived and spatially localized regions where a scalar field (e.g., the inflaton) oscillates with large amplitude. Contrary to a previous study, which considered a symmetric potential, we find that oscillons in asymmetric potentials associated with a phase transition can generate a pronounced peak in the spectrum of gravitational waves that largely exceeds the linear preheating spectrum. We discuss the possible implications of this enhanced amplitude of gravitational waves. For instance, for low scale inflation models, the contribution from the oscillons can strongly enhance the observation prospects at current and future gravitational wave detectors.
Gravitational Waves: A New Observational Window
NASA Technical Reports Server (NTRS)
Camp, Jordan B.
2010-01-01
The era of gravitational wave astronomy is rapidly approaching, with a likely start date around the middle of this decade ' Gravitational waves, emitted by accelerated motions of very massive objects, provide detailed information about strong-field gravity and its sources, including black holes and neutron stars, that electromagnetic probes cannot access. In this talk I will discuss the anticipated sources and the status of the extremely sensitive detectors (both ground and space based) that will make gravitational wave detections possible. As ground based detectors are now taking data, I will show some initial science results related to measured upper limits on gravitational wave signals. Finally Z will describe new directions including advanced detectors and joint efforts with other fields of astronomy.
Gravitational Waves and Time Domain Astronomy
NASA Technical Reports Server (NTRS)
Centrella, Joan; Nissanke, Samaya; Williams, Roy
2012-01-01
The gravitational wave window onto the universe will open in roughly five years, when Advanced LIGO and Virgo achieve the first detections of high frequency gravitational waves, most likely coming from compact binary mergers. Electromagnetic follow-up of these triggers, using radio, optical, and high energy telescopes, promises exciting opportunities in multi-messenger time domain astronomy. In the decade, space-based observations of low frequency gravitational waves from massive black hole mergers, and their electromagnetic counterparts, will open up further vistas for discovery. This two-part workshop featured brief presentations and stimulating discussions on the challenges and opportunities presented by gravitational wave astronomy. Highlights from the workshop, with the emphasis on strategies for electromagnetic follow-up, are presented in this report.
Gravitational Wave Detection with Atom Interferometry
Dimopoulos, Savas; Graham, Peter W.; Hogan, Jason M.; Kasevich, Mark A.; Rajendran, Surjeet; /SLAC /Stanford U., Phys. Dept.
2008-01-23
We propose two distinct atom interferometer gravitational wave detectors, one terrestrial and another satellite-based, utilizing the core technology of the Stanford 10m atom interferometer presently under construction. The terrestrial experiment can operate with strain sensitivity {approx} 10{sup -19}/{radical}Hz in the 1 Hz-10 Hz band, inaccessible to LIGO, and can detect gravitational waves from solar mass binaries out to megaparsec distances. The satellite experiment probes the same frequency spectrum as LISA with better strain sensitivity {approx} 10{sup -20}/{radical}Hz. Each configuration compares two widely separated atom interferometers run using common lasers. The effect of the gravitational waves on the propagating laser field produces the main effect in this configuration and enables a large enhancement in the gravitational wave signal while significantly suppressing many backgrounds. The use of ballistic atoms (instead of mirrors) as inertial test masses improves systematics coming from vibrations and acceleration noise, and reduces spacecraft control requirements.
LISA: Detecting Gravitational Waves from Space
NASA Technical Reports Server (NTRS)
Livas, Jeff
2009-01-01
The laser interferometer space antenna (LISA), a joint NASA/ESA mission, will be the first dedicated gravitational wave detector in space. This presentation will provide a tutorial of the LISA measurement concept.
Particle production in a gravitational wave background
NASA Astrophysics Data System (ADS)
Jones, Preston; McDougall, Patrick; Singleton, Douglas
2017-03-01
We study the possibility that massless particles, such as photons, are produced by a gravitational wave. That such a process should occur is implied by tree-level Feynman diagrams such as two gravitons turning into two photons, i.e., g +g →γ +γ . Here we calculate the rate at which a gravitational wave creates a massless scalar field. This is done by placing the scalar field in the background of a plane gravitational wave and calculating the 4-current of the scalar field. Even in the vacuum limit of the scalar field it has a nonzero vacuum expectation value (similar to what occurs in the Higgs mechanism) and a nonzero current. We associate this with the production of scalar field quanta by the gravitational field. This effect has potential consequences for the attenuation of gravitational waves since the massless field is being produced at the expense of the gravitational field. This is related to the time-dependent Schwinger effect, but with the electric field replaced by the gravitational wave background and the electron/positron field quanta replaced by massless scalar "photons." Since the produced scalar quanta are massless there is no exponential suppression, as occurs in the Schwinger effect due to the electron mass.
Transformations of asymptotic gravitational-wave data
NASA Astrophysics Data System (ADS)
Boyle, Michael
2016-04-01
Gravitational-wave data is gauge dependent. While we can restrict the class of gauges in which such data may be expressed, there will still be an infinite-dimensional group of transformations allowed while remaining in this class, and almost as many different—though physically equivalent—waveforms as there are transformations. This paper presents a method for calculating the effects of the most important transformation group, the Bondi-Metzner-Sachs (BMS) group, consisting of rotations, boosts, and supertranslations (which include time and space translations as special cases). To a reasonable approximation, these transformations result in simple coupling between the modes in a spin-weighted spherical-harmonic decomposition of the waveform. It is shown that waveforms from simulated compact binaries in the publicly available SXS waveform catalog contain unmodeled effects due to displacement and drift of the center of mass, accounting for mode mixing at typical levels of 1%. However, these effects can be mitigated by measuring the average motion of the system's center of mass for a portion of the inspiral, and applying the opposite transformation to the waveform data. More generally, controlling the BMS transformations will be necessary to eliminate the gauge ambiguity inherent in gravitational-wave data for both numerical and analytical waveforms. Open-source code implementing BMS transformations of waveforms is supplied along with this paper in the supplemental materials.
The Path to Gravitational Wave Detection
NASA Astrophysics Data System (ADS)
Barish, Barry
2017-01-01
Experimental efforts toward gravitational wave detection began with the innovative resonant bar experiments of Joseph Weber in the 1960s. This technique evolved, but was eventually replaced by the potentially more sensitive suspended mass interferometers. Large scale interferometers, GEO, LIGO and Virgo were funded in 1994. The 22 year history since that time will be discussed, tracing the key technical challenges and solutions that have enabled LIGO to reach the incredible sensitivities where gravitational waves from binary black hole mergers have been observed.
Gravitational waves and the early universe
NASA Astrophysics Data System (ADS)
Boyle, Latham A.
Can we detect primordial gravitational waves ( i.e. tensor perturbations)? If so, what will they teach us about the early universe? These two questions are central to this two part thesis. First, in chapters 2 and 3, we compute the gravitational wave spectrum produced by inflation. We argue that if inflation is correct, then the scalar spectral index n s should satisfy n s [Special characters omitted.] 0.98; and if n s satisfies 0.95 [Special characters omitted.] n s [Special characters omitted.] 0.98, then the tensor-to-scalar ratio r should satisfy r [Special characters omitted.] 0.01. This means that, if inflation is correct, then primordial gravitational waves are likely to be detectable. We compute in detail the "tensor transfer function" T t ( k, t) which relates the tensor power spectrum at two different times t 1 and t 2 , and the "tensor extrapolation function" E t ( k, k [low *] ) which relates the primordial tensor power spectrum at two different wavenumbers k and k [low *] . By analyzing these two expressions, we show that inflationary gravitational waves should yield crucial clues about inflation itself, and about the "primordial dark age" between the end of inflation and the start of big bang nucleosynthesis (BBN). Second, in chapters 4 and 5, we compute the gravitational wave spectrum produced by the cyclic model. We examine a surprising duality relating expanding and contracting cosmological models that generate the same spectrum of gauge-invariant Newtonian potential fluctuations. This means that, if the cyclic model is correct, then it cannot be distinguished from inflation by observing primordial scalar perturbations alone. Fortunately, gravitational waves may be used to cleanly discriminate between the inflationary and cyclic scenarios: we show that BBN constrains the gravitational wave spectrum generated by the cyclic model to be so suppressed that it cannot be detected by any known experiment. Thus, the detection of a primordial gravitational
The pregalactic cosmic gravitational wave background
NASA Technical Reports Server (NTRS)
Matzner, Richard A.
1989-01-01
An outline is given that estimates the expected gravitational wave background, based on plausible pregalactic sources. Some cosmologically significant limits can be put on incoherent gravitational wave background arising from pregalactic cosmic evolution. The spectral region of cosmically generated and cosmically limited radiation is, at long periods, P greater than 1 year, in contrast to more recent cosmological sources, which have P approx. 10 to 10(exp -3).
Time Evolution of Pure Gravitational Waves
NASA Astrophysics Data System (ADS)
Miyama, S. M.
1981-03-01
Numerical solutions to the Einstein equations in the case of pure gravitational waves are given. The system is assumed to be axially symmetric and non-rotating. The time symmetric initial data and the conformally flat initial data are obtained by solving the constraint equations at t=0. The time evolution of these initial data depends strongly on the initial amplitude of the gravitational waves. In the case of the low initial amplitude, waves only disperse to null infinity. By comparing the initial gravitational energy with the total energy loss through an r=constant surface, it is concluded that the Newman-Penrose method and the Gibbon-Hawking method are the most desirable for measuring the energy flux of gravitational radiation numerically. In the case that the initial ratio of the spatial extent of the gravitational waves to the Schwarzschild radius (M/2) is smaller than about 300, the waves collapse by themselves, leading to formation of a black hole. The analytic solutions of the linearized Einstein equations for the pure gravitational waves are also shown.
BOOK REVIEW Analysis of Gravitational-Wave Data Analysis of Gravitational-Wave Data
NASA Astrophysics Data System (ADS)
Fairhurst, Stephen
2010-12-01
The field of gravitational-wave data analysis has expanded greatly over the past decade and significant developments have been made in methods of analyzing the data taken by resonant bar and interferometric detectors, as well as analysis of mock LISA data. This book introduces much of the required theoretical background in gravitational physics, statistics and time series analysis before moving on to a discussion of gravitational-wave data analysis techniques themselves. The book opens with an overview of the theory of gravitational radiation, providing a comprehensive discussion of various introductory topics: linearized gravity, transverse traceless gauge, the effects of gravitational waves (via geodesic deviation), energy and momentum carried by the waves, and generation of gravitational waves. The second chapter provides an introduction to the various sources of gravitational waves, followed by more detailed expositions on some of the primary sources. For example, the description of compact binary coalescence is thorough and includes a brief exposition of the post-Newtonian formalism and the effective one body method. There also follows extended derivations of gravitational waves from distorted neutron stars, supernovae and a stochastic background. Chapter three provides an introduction to the statistical theory of signal detection, including a discussion of parameter estimation via the Fisher matrix formalism. This is presented from a very mathematical, postulate based, standpoint and I expect that even established gravitational-wave data analysts will find the derivations here more formal than they are used to. The discussion of likelihood ratio tests and the importance of prior probabilities are presented particularly clearly. The fourth chapter covers time series analysis, with power spectrum estimation, extraction of periodic signals and goodness of fit tests. Chapter five switches topics and gives the details of the response of gravitational-wave
On the direct detection of gravitational waves
NASA Astrophysics Data System (ADS)
Pustovoit, V. I.
2016-10-01
Different types of gravitational wave (GW) detectors are considered. It is noted that interferometric techniques offer the greatest prospects for GW registration due to their high sensitivity and extremely wide frequency band. Using laser interferometers, proposed as far back as 1962 in the work by M E Gertsenshtein and V I Pustovoit published in Russian (Zh. Eksp. Teor. Fiz., vol. 43, p. 605, 1962) and in English translation (Sov. Phys. JETP, vol. 16, p. 433, 1963), it proved possible for the first time to directly detect GW emission from a merger of two black holes. It is noted that the assertion that Gertsen-shtein-Pustovoit's work was unknown to some of those experts involved in direct GW detection is inconsistent with reality. The problems of high-power laser radiation affecting the electrostatic polarization of free-mass mirrors are discussed. It is shown that mirror polarization can lead to additional links with electrically conducting elements of the design resulting in the interferometer's reduced sensitivity. Some new prospects for developing high reflection structures are discussed and heat extraction problems are considered. This article is the revised and extended version of the report “On the first direct detection of gravitational waves” delivered by V I Pustovoit at the Scientific Session of the Physical Sciences Division of the Russian Academy of Sciences (March 2, 2016). All other reports presented at the session were published in the preceding issue of Physics-Uspekhi (September 2016) (see Refs [108, 111-113]). (Editorial note)
LISA: Science and Prospects for Gravitational Wave Detection in Space
NASA Astrophysics Data System (ADS)
Larson, Shane L.
2017-01-01
Spaceborne gravitational wave observatories with million kilometer armlengths will probe gravitational waves with kilosecond periods. This part of the spectrum is populated by a diverse menagerie of high energy astrophysical systems that will give new insights into stellar evolution, the formation and evolution of super-massive black holes, and the growth of structure in the Universe. LISA is a laser interferometric observatory that will be sensitive to gravitational wave frequencies from about 10 microHertz to about 1 Hertz, providing gravitational wave observations of these phenomena that will enable population studies, detailed characterization of the structure and bulk motion of matter in these systems, as well as enabling new, detailed tests of physics in strong gravitational fields. The core LISA measurement has been demonstrated by the successful flight of LISA Pathfinder, paving the way for the start of LISA mission design and planning. In this talk, we will discuss the science that low-frequency gravitational wave observations will reveal and enable, as well as the current technology status and progress forward toward an eventual LISA flight.
Gravitational Waves from a Dark Phase Transition
NASA Astrophysics Data System (ADS)
Schwaller, Pedro
2015-10-01
In this work, we show that a large class of models with a composite dark sector undergo a strong first order phase transition in the early Universe, which could lead to a detectable gravitational wave signal. We summarize the basic conditions for a strong first order phase transition for SU (N ) dark sectors with nf flavors, calculate the gravitational wave spectrum and show that, depending on the dark confinement scale, it can be detected at eLISA or in pulsar timing array experiments. The gravitational wave signal provides a unique test of the gravitational interactions of a dark sector, and we discuss the complementarity with conventional searches for new dark sectors. The discussion includes the twin Higgs and strongly interacting massive particle models as well as symmetric and asymmetric composite dark matter scenarios.
Hearing the signal of dark sectors with gravitational wave detectors
NASA Astrophysics Data System (ADS)
Jaeckel, Joerg; Khoze, Valentin V.; Spannowsky, Michael
2016-11-01
Motivated by advanced LIGO (aLIGO)'s recent discovery of gravitational waves, we discuss signatures of new physics that could be seen at ground- and space-based interferometers. We show that a first-order phase transition in a dark sector would lead to a detectable gravitational wave signal at future experiments, if the phase transition has occurred at temperatures few orders of magnitude higher than the electroweak scale. The source of gravitational waves in this case is associated with the dynamics of expanding and colliding bubbles in the early universe. At the same time we point out that topological defects, such as dark sector domain walls, may generate a detectable signal already at aLIGO. Both bubble and domain-wall scenarios are sourced by semiclassical configurations of a dark new physics sector. In the first case, the gravitational wave signal originates from bubble wall collisions and subsequent turbulence in hot plasma in the early universe, while the second case corresponds to domain walls passing through the interferometer at present and is not related to gravitational waves. We find that aLIGO at its current sensitivity can detect smoking-gun signatures from domain-wall interactions, while future proposed experiments including the fifth phase of aLIGO at design sensitivity can probe dark sector phase transitions.
Expected sources and data analysis on laser interferometric gravitational wave detector
NASA Astrophysics Data System (ADS)
Kanda, Nobuyuki
2001-10-01
The direct detection of gravitational wave has been expected for physics in strong gravitational field, and for a new deep probe for astronomical objects. Recently, some projects of large-scale laser interferometric gravitational wave detector compete for the first detection of gravitational wave. Our project TAMA300 which is placed in NAOJ, achieved worlds best sensitivity and long stable operation as a realistic observatory. In this document, we will give a brief description of gravitational wave detection, expected sources, and TAMA's data analysis.
How to test gravitation theories by means of gravitational-wave measurements
NASA Technical Reports Server (NTRS)
Thorne, K. S.
1974-01-01
Gravitational-wave experiments are a potentially powerful tool for testing gravitation theories. Most theories in the literature predict rather different polarization properties for gravitational waves than are predicted by general relativity; and many theories predict anomalies in the propagation speeds of gravitational waves.
Nearby Stars as Gravitational Wave Detectors
NASA Astrophysics Data System (ADS)
Lopes, Ilídio; Silk, Joseph
2015-07-01
Sun-like stellar oscillations are excited by turbulent convection and have been discovered in some 500 main-sequence and sub-giant stars and in more than 12,000 red giant stars. When such stars are near gravitational wave sources, low-order quadrupole acoustic modes are also excited above the experimental threshold of detectability, and they can be observed, in principle, in the acoustic spectra of these stars. Such stars form a set of natural detectors to search for gravitational waves over a large spectral frequency range, from {10}-7 to {10}-2 Hz. In particular, these stars can probe the {10}-6-{10}-4 Hz spectral window which cannot be probed by current conventional gravitational wave detectors, such as the Square Kilometre Array and Evolved Laser Interferometer Space Antenna. The Planetary Transits and Oscillations of State (PLATO) stellar seismic mission will achieve photospheric velocity amplitude accuracy of {cm} {{{s}}}-1. For a gravitational wave search, we will need to achieve accuracies of the order of {10}-2 {cm} {{{s}}}-1, i.e., at least one generation beyond PLATO. However, we have found that multi-body stellar systems have the ideal setup for this type of gravitational wave search. This is the case for triple stellar systems formed by a compact binary and an oscillating star. Continuous monitoring of the oscillation spectra of these stars to a distance of up to a kpc could lead to the discovery of gravitational waves originating in our galaxy or even elsewhere in the universe. Moreover, unlike experimental detectors, this observational network of stars will allow us to study the progression of gravitational waves throughout space.
Binary Black Holes and Gravitational Waves
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LIGO and LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these wave patterns. For more than 30 years, scientists have tried to compute these wave patterns. However, their computer codes have been plagued by problems that caused them to crash. This situation has changed dramatically in the past 2 years, with a series of amazing breakthroughs. This discussion examines these gravitational patterns, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. The focus is on recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by the space-based gravitational wave detector LISA.
Space-borne gravitational wave observatories
NASA Astrophysics Data System (ADS)
Vitale, Stefano
2014-05-01
The paper describes the progress toward a space-borne gravitational wave observatory and its foreseeable science potential. In particular the paper describes the status of the LISA-like mission called eLISA, the reference mission for the Gravitational Universe theme adopted by ESA for its Large mission L3, and the status of its precursor LISA Pathfinder, due to launch in 2015.
LIGO: The Laser Interferometer Gravitational-Wave Observatory.
Abramovici, A; Althouse, W E; Drever, R W; Gürsel, Y; Kawamura, S; Raab, F J; Shoemaker, D; Sievers, L; Spero, R E; Thorne, K S; Vogt, R E; Weiss, R; Whitcomb, S E; Zucker, M E
1992-04-17
The goal of the Laser Interferometer Gravitational-Wave Observatory (LIGO) Project is to detect and study astrophysical gravitational waves and use data from them for research in physics and astronomy. LIGO will support studies concerning the nature and nonlinear dynamics of gravity, the structures of black holes, and the equation of state of nuclear matter. It will also measure the masses, birth rates, collisions, and distributions of black holes and neutron stars in the universe and probe the cores of supernovae and the very early universe. The technology for LIGO has been developed during the past 20 years. Construction will begin in 1992, and under the present schedule, LIGO's gravitational-wave searches will begin in 1998.
Exploring Gravitational Waves in the Classroom
NASA Astrophysics Data System (ADS)
Cominsky, Lynn R.; McLin, Kevin M.; Peruta, Carolyn; Simonnet, Aurore
2016-04-01
On September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) received the first confirmed gravitational wave signals. Now known as GW150914 (for the date on which the signals were received), the event represents the coalescence of two black holes that were previously in mutual orbit. LIGO’s exciting discovery provides direct evidence of what is arguably the last major unconfirmed prediction of Einstein’s General Theory of Relativity. The Education and Public Outreach group at Sonoma State University has created an educator's guide that provides a brief introduction to LIGO and to gravitational waves, along with two simple demonstration activities that can be done in the classroom to engage students in understanding LIGO’s discovery. Additional resources have also been provided to extend student explorations of Einstein’s Universe.
General-relativistic astrophysics. [gravitational wave astronomy
NASA Technical Reports Server (NTRS)
Thorne, K. S.
1978-01-01
The overall relevance of general relativity to astrophysics is considered, and some of the knowledge about the ways in which general relativity should influence astrophysical systems is reviewed. Attention is focused primarily on finite-sized astrophysical systems, such as stars, globular clusters, galactic nuclei, and primordial black holes. Stages in the evolution of such systems and tools for studying the effects of relativistic gravity in these systems are examined. Gravitational-wave astronomy is discussed in detail, with emphasis placed on estimates of the strongest gravitational waves that bathe earth, present obstacles and future prospects for detection of the predicted waves, the theory of small perturbations of relativistic stars and black holes, and the gravitational waves such objects generate. Characteristics of waves produced by black-hole events in general, pregalactic black-hole events, black-hole events in galactic nuclei and quasars, black-hole events in globular clusters, the collapse of normal stars to form black holes or neutron stars, and corequakes in neutron stars are analyzed. The state of the art in gravitational-wave detection and characteristics of various types of detector are described.
Gravitational Waves from Coalescing Binary Black Holes: Theoretical and Experimental Challenges
None
2016-07-12
A network of ground-based interferometric gravitational wave detectors (LIGO/VIRGO/GEO/...) is currently taking data near its planned sensitivity. Coalescing black hole binaries are among the most promising, and most exciting, gravitational wave sources for these detectors. The talk will review the theoretical and experimental challenges that must be met in order to successfully detect gravitational waves from coalescing black hole binaries, and to be able to reliably measure the physical parameters of the source (masses, spins, ...).
Gravitational Wave Detection: A Historical Perspective
NASA Astrophysics Data System (ADS)
Saulson, Peter
2015-04-01
The search for gravitational waves began at the Chapel Hill Conference in January 1957, and will reach a successful conclusion at a set of observatories around the globe about sixty years later. This talk will review the history of the early thought experiments, the program of resonant mass detectors (``Weber bars''), and the development of the large interferometric detectors like Advanced LIGO and Advanced Virgo that are, it is hoped, about to make the first detections of gravitational wave signals. I am pleased to acknowledge the support of the National Science Foundation for my research, most recently under NSF Grant PHY-1205835.
Gravitational Waves and Multi-Messenger Astronomy
NASA Technical Reports Server (NTRS)
Centrella, Joan M.
2010-01-01
Gravitational waves are produced by a wide variety of sources throughout the cosmos, including the mergers of black hole and neutron star binaries/compact objects spiraling into central black holes in galactic nuclei, close compact binaries/and phase transitions and quantum fluctuations in the early universe. Observing these signals can bring new, and often very precise, information about their sources across vast stretches of cosmic time. In this talk we will focus on thee opening of this gravitational-wave window on the universe, highlighting new opportunities for discovery and multi-messenger astronomy.
Gravitational waves induced by spinor fields
NASA Astrophysics Data System (ADS)
Feng, Kaixi; Piao, Yun-Song
2015-07-01
In realistic model building, spinor fields with various masses are present. During inflation, a spinor field may induce gravitational waves as a second order effect. In this paper, we calculate the contribution of a single massive spinor field to the power spectrum of primordial gravitational wave by using a retarded Green propagator. We find that the correction is scale invariant and of order H4/MP4 for arbitrary spinor mass mψ. Additionally, we also observe that when mψ≳H , the dependence of correction on mψ/H is nontrivial.
Gravitational waves in a de Sitter universe
NASA Astrophysics Data System (ADS)
Bishop, Nigel T.
2016-02-01
The construction of exact linearized solutions to the Einstein equations within the Bondi-Sachs formalism is extended to the case of linearization about de Sitter spacetime. The gravitational wave field measured by distant observers is constructed, leading to a determination of the energy measured by such observers. It is found that gravitational wave energy conservation does not normally apply to inertial observers but that it can be formulated for a class of accelerated observers, i.e., with worldlines that are timelike but not geodesic.
Toward loop quantization of plane gravitational waves
NASA Astrophysics Data System (ADS)
Hinterleitner, Franz; Major, Seth
2012-03-01
The polarized Gowdy model in terms of Ashtekar-Barbero variables is reduced with an additional constraint derived from the Killing equations for plane gravitational waves with parallel rays. The new constraint is formulated in a diffeomorphism invariant manner and, when it is included in the model, the resulting constraint algebra is first class, in contrast to the prior work done in special coordinates. Using an earlier work by Banerjee and Date, the constraints are expressed in terms of classical quantities that have an operator equivalent in loop quantum gravity, making these plane gravitational wave spacetimes accessible to loop quantization techniques.
Detection of gravitational waves: a hundred year journey
NASA Astrophysics Data System (ADS)
Mavalvala, Nergis
2016-05-01
In February 2016, scientists announced the first ever detection of gravitational waves from colliding black holes, launching a new era of gravitational wave astronomy and unprecedented tests of Einstein's theory of general relativity. I will describe the science and technology, and also the human story, behind the long quest that led to this discovery. Bio: Nergis Mavalvala is Professor of Physics at the Massachusetts Institute of Technology (MIT). Her research links the world of quantum mechanics, usually apparent only at the atomic scale, with gravitational waves, arising from some of the most powerful, yet elusive, forces in the cosmos. In 2016, she was part of the team that announced the first detection of gravitational waves from colliding black holes. She received a B.A. from Wellesley College in 1990 and a Ph.D. from MIT in 1997. She was a postdoctoral fellow and research scientist at the California Institute of Technology between 1997 and 2002. Since 2002, she has been on the Physics faculty at MIT, and was named a MacArthur Fellow in 2010. She is a Fellow of the American Physical Society and the Optical Society of America.
Ultrahigh precision cosmology from gravitational waves
Cutler, Curt; Holz, Daniel E.
2009-11-15
We show that the Big Bang Observer (BBO), a proposed space-based gravitational-wave (GW) detector, would provide ultraprecise measurements of cosmological parameters. By detecting {approx}3x10{sup 5} compact-star binaries, and utilizing them as standard sirens, BBO would determine the Hubble constant to {approx}0.1%, and the dark-energy parameters w{sub 0} and w{sub a} to {approx}0.01 and {approx}0.1, respectively. BBO's dark-energy figure-of-merit would be approximately an order of magnitude better than all other proposed, dedicated dark-energy missions. To date, BBO has been designed with the primary goal of searching for gravitational waves from inflation, down to the level {omega}{sub GW}{approx}10{sup -17}; this requirement determines BBO's frequency band (deci-Hz) and its sensitivity requirement (strain measured to {approx}10{sup -24}). To observe an inflationary GW background, BBO would first have to detect and subtract out {approx}3x10{sup 5} merging compact-star binaries, out to a redshift z{approx}5. It is precisely this carefully measured foreground which would enable high-precision cosmology. BBO would determine the luminosity distance to each binary to {approx} percent accuracy. In addition, BBO's angular resolution would be sufficient to uniquely identify the host galaxy for the majority of binaries; a coordinated optical/infrared observing campaign could obtain the redshifts. Combining the GW-derived distances and the electromagnetically-derived redshifts for such a large sample of objects, out to such high redshift, naturally leads to extraordinarily tight constraints on cosmological parameters. We emphasize that such 'standard siren' measurements of cosmology avoid many of the systematic errors associated with other techniques: GWs offer a physics-based, absolute measurement of distance. In addition, we show that BBO would also serve as an exceptionally powerful gravitational-lensing mission, and we briefly discuss other astronomical uses of BBO
Ultrahigh precision cosmology from gravitational waves
NASA Astrophysics Data System (ADS)
Cutler, Curt; Holz, Daniel E.
2009-11-01
We show that the Big Bang Observer (BBO), a proposed space-based gravitational-wave (GW) detector, would provide ultraprecise measurements of cosmological parameters. By detecting ˜3×105 compact-star binaries, and utilizing them as standard sirens, BBO would determine the Hubble constant to ˜0.1%, and the dark-energy parameters w0 and wa to ˜0.01 and ˜0.1, respectively. BBO’s dark-energy figure-of-merit would be approximately an order of magnitude better than all other proposed, dedicated dark-energy missions. To date, BBO has been designed with the primary goal of searching for gravitational waves from inflation, down to the level ΩGW˜10-17; this requirement determines BBO’s frequency band (deci-Hz) and its sensitivity requirement (strain measured to ˜10-24). To observe an inflationary GW background, BBO would first have to detect and subtract out ˜3×105 merging compact-star binaries, out to a redshift z˜5. It is precisely this carefully measured foreground which would enable high-precision cosmology. BBO would determine the luminosity distance to each binary to ˜ percent accuracy. In addition, BBO’s angular resolution would be sufficient to uniquely identify the host galaxy for the majority of binaries; a coordinated optical/infrared observing campaign could obtain the redshifts. Combining the GW-derived distances and the electromagnetically-derived redshifts for such a large sample of objects, out to such high redshift, naturally leads to extraordinarily tight constraints on cosmological parameters. We emphasize that such “standard siren” measurements of cosmology avoid many of the systematic errors associated with other techniques: GWs offer a physics-based, absolute measurement of distance. In addition, we show that BBO would also serve as an exceptionally powerful gravitational-lensing mission, and we briefly discuss other astronomical uses of BBO, including providing an early warning system for all short/hard gamma-ray bursts.
Gravitational waves from compact objects
NASA Astrophysics Data System (ADS)
de Freitas Pacheco, José Antonio
2010-11-01
Large ground-based laser beam interferometers are presently in operation both in the USA (LIGO) and in Europe (VIRGO) and potential sources that might be detected by these instruments are revisited. The present generation of detectors does not have a sensitivity high enough to probe a significant volume of the universe and, consequently, predicted event rates are very low. The planned advanced generation of interferometers will probably be able to detect, for the first time, a gravitational signal. Advanced LIGO and EGO instruments are expected to detect few (some): binary coalescences consisting of either two neutron stars, two black holes or a neutron star and a black hole. In space, the sensitivity of the planned LISA spacecraft constellation will allow the detection of the gravitational signals, even within a “pessimistic" range of possible signals, produced during the capture of compact objects by supermassive black holes, at a rate of a few tens per year.
Outlook for Detecting Gravitational Waves with Pulsars
NASA Astrophysics Data System (ADS)
Kohler, Susanna
2016-04-01
Though the recent discovery of GW150914 is a thrilling success in the field of gravitational-wave astronomy, LIGO is only one tool the scientific community is using to hunt for these elusive signals. After 10 years of unsuccessful searching, how likely is it that pulsar-timing-array projects will make their own first detection soon?Frequency ranges for gravitational waves produced by different astrophysical sources. Pulsar timing arrays such as the EPTA and IPTA are used to detect low-frequency gravitational waves generated by the stochastic background and supermassive black hole binaries. [Christopher Moore, Robert Cole and Christopher Berry]Supermassive BackgroundGround-based laser interferometers like LIGO are ideal for probing ripples in space-time caused by the merger of stellar-mass black holes; these mergers cause chirps in the frequency range of tens to thousands of hertz. But how do we pick up the extremely low-frequency, nanohertz background signal caused by the orbits of pairs of supermassive black holes? For that, we need pulsar timing arrays.Pulsar timing arrays are sets of pulsars whose signals are analyzed to look for correlations in the pulse arrival time. As the space-time between us and a pulsar is stretched and then compressed by a passing gravitational wave, the pulsars pulses should arrive a little late and then a little early. Comparing these timing residuals in an array of pulsars could theoretically allow for the detection of the gravitational waves causing them.Globally, there are currently four pulsar timing array projects actively searching for this signal, with a fifth planned for the future. Now a team of scientists led by Stephen Taylor (NASA-JPL/Caltech) has estimated the likelihood that these projects will successfully detect gravitational waves in the future.Probability for SuccessExpected detection probability of the gravitational-wave background as a function of observing time, for five different pulsar timing arrays. Optimistic
Physical optics in a uniform gravitational field
NASA Astrophysics Data System (ADS)
Hacyan, Shahen
2012-01-01
The motion of a (quasi-)plane wave in a uniform gravitational field is studied. It is shown that the energy of an elliptically polarized wave does not propagate along a geodesic, but in a direction that is rotated with respect to the gravitational force. The similarity with the walk-off effect in anisotropic crystals or the optical Magnus effect in inhomogeneous media is pointed out.
Space Detection of Gravitational Waves (lisa)
NASA Astrophysics Data System (ADS)
de Araujo, J. C. Neves; Buchman, S.; Cavalleri, A.; Danzmann, K.; Doles, R.; Fontana, G.; Hanso, J.; Hueller, M.; Sigurdsso, S.; Turneaure, J.; Ungarell, C.; Vecchi, A.; Vital, S.; Webe, W.
2002-12-01
The Laser Interferometer Space Antenna (LISA) mission is designed to observe gravitational waves from galactic and extra-galactic binary systems, including gravitational waves generated in the vicinity of the very massive black holes found in the centers of many galaxies. Acting as a giant Michelson interferometer the three spacecraft flying 5 million km apart will open the era of astronomy in the gravitational spectrum. We give an introduction to the mission and describe the status of selected experimental, theoretical, and planning LISA work, as reported at the Ninth Marcel Grossman Meeting in 2000 in Rome. We discuss the three areas of technology challenges facing the mission inertial sensors, micronewton thrusters, and picometer interferometry. We report on the progress in the development of free falling moving test-masses for LISA and for the related technology demonstration mission. We present simple formulas to evaluate the performance of the device as a function of the various design parameters, and we compare them with preliminary experimental results from a test prototype we are developing. Quantitative agreement is found. The gravitational radiation emitted during the final stages of coalescence of stellar mass compact objects with low massive black holes is a signal detectable by LISA. It will also provide the opportunity of measuring relativistic strong field effects. A brief discussion addresses the detection by LISA of gravitational waves generated by cataclysmic binary variables at frequencies below 1 mHz. Finally the prospects for cosmology work with LISA type antennas are being analyzed.
Space Based Gravitational Wave Observatories (SGOs)
NASA Technical Reports Server (NTRS)
Livas, Jeff
2014-01-01
Space-based Gravitational-wave Observatories (SGOs) will enable the systematic study of the frequency band from 0.0001 - 1 Hz of gravitational waves, where a rich array of astrophysical sources is expected. ESA has selected The Gravitational Universe as the science theme for the L3 mission opportunity with a nominal launch date in 2034. This will be at a minimum 15 years after ground-based detectors and pulsar timing arrays announce their first detections and at least 18 years after the LISA Pathfinder Mission will have demonstrated key technologies in a dedicated space mission. It is therefore important to develop mission concepts that can take advantage of the momentum in the field and the investment in both technology development and a precision measurement community on a more near-term timescale than the L3 opportunity. This talk will discuss a mission concept based on the LISA baseline that resulted from a recent mission architecture study.
Bayesian analysis on gravitational waves and exoplanets
NASA Astrophysics Data System (ADS)
Deng, Xihao
Attempts to detect gravitational waves using a pulsar timing array (PTA), i.e., a collection of pulsars in our Galaxy, have become more organized over the last several years. PTAs act to detect gravitational waves generated from very distant sources by observing the small and correlated effect the waves have on pulse arrival times at the Earth. In this thesis, I present advanced Bayesian analysis methods that can be used to search for gravitational waves in pulsar timing data. These methods were also applied to analyze a set of radial velocity (RV) data collected by the Hobby- Eberly Telescope on observing a K0 giant star. They confirmed the presence of two Jupiter mass planets around a K0 giant star and also characterized the stellar p-mode oscillation. The first part of the thesis investigates the effect of wavefront curvature on a pulsar's response to a gravitational wave. In it we show that we can assume the gravitational wave phasefront is planar across the array only if the source luminosity distance " 2piL2/lambda, where L is the pulsar distance to the Earth (˜ kpc) and lambda is the radiation wavelength (˜ pc) in the PTA waveband. Correspondingly, for a point gravitational wave source closer than ˜ 100 Mpc, we should take into account the effect of wavefront curvature across the pulsar-Earth line of sight, which depends on the luminosity distance to the source, when evaluating the pulsar timing response. As a consequence, if a PTA can detect a gravitational wave from a source closer than ˜ 100 Mpc, the effects of wavefront curvature on the response allows us to determine the source luminosity distance. The second and third parts of the thesis propose a new analysis method based on Bayesian nonparametric regression to search for gravitational wave bursts and a gravitational wave background in PTA data. Unlike the conventional Bayesian analysis that introduces a signal model with a fixed number of parameters, Bayesian nonparametric regression sets
Searching for gravitational waves from neutron stars
NASA Astrophysics Data System (ADS)
Idrisy, Ashikuzzaman
generate the parameter space of a GW search so as to cover the largest physical range of parameters, while keeping the search computationally feasible. Finally we discuss the time-domain solar system barycentered resampling algorithm as a way to improve to the computational cost of the analysis. In Chapter 4 we discuss a search for GWs from two supernova remnants, G65.7 and G330.2. The searches were conducted using data from the 6th science run of the LIGO detectors. Since the searches were modeled on the Cassiopeia A search paper, Abadie et. al. [Astrophys. J. 722,1504--1513, 2010], we also used the frequency and the first and second derivatives of the frequency as the parameter space of the search. There are two main differences from the previous search. The first is the use of the resampling algorithm, which sped up the calculation of the F-statistic by a factor of 3 and thus allowed for longer stretches of data to be coherently integrated. Being able to integrate more data meant that we could beat the indirect limit on GWs expected from these sources. We used a 51 day integration time for G65.7 and 24 days for G330.2. The second difference is that the analysis pipeline is now more automated. This allows for a more efficient data analysis process. We did not find a credible source of GWs and so we placed upper limits on the gravitational wave strain, ellipticity, and r-mode amplitude of the sources. The best upper-limit for the strain was 3.0 x 10 -25, for ellipticity it was 7.0 x 10-6 and for r-mode amplitude it was 2.2 x 10-4 .
Quantum nondemolition measurements. [by gravitational wave antennas
NASA Technical Reports Server (NTRS)
Braginskii, V. B.; Vorontsov, Iu. I.; Thorne, K. S.
1980-01-01
The article describes new electronic techniques required for quantum nondemolition measurements and the theory underlying them. Consideration is given to resonant-bar gravitational-wave antennas. Position measurements are discussed along with energy measurements and back-action-evading measurements. Thermal noise in oscillators and amplifiers is outlined. Prospects for stroboscopic measurements are emphasized.
Insights into the gravitational wave memory effect
NASA Astrophysics Data System (ADS)
Bieri, Lydia
2017-01-01
A major breakthrough of General Relativity (GR) happened in 2015 with LIGO's first detection of gravitational waves. Typical sources for gravitational radiation are mergers of binary black holes, binary neutron stars and core-collapse supernovae. In these processes mass and momenta are radiated away in form of gravitational waves. GR predicts that these waves leave a footprint in the spacetime, that is they change the spacetime permanently, which results in a permanent displacement of test masses. This effect is called the memory. In this talk, I will explore the gravitational wave memory. We will see that there are two types of memory, one going back to Ya. B. Zel'dovich and A. G. Polnarev and one to D. Christodoulou. Then I will discuss recent work including my collaboration with D. Garfinkle, S.-T. Yau, P. Chen, focusing on how neutrinos or electromagnetic fields contribute to the memory effect, and work with D. Garfinkle and N. Yunes on cosmological memory. The author thanks NSF for support by grant DMS-1253149 to The University of Michigan.
Ground-based gravitational-wave detectors
NASA Astrophysics Data System (ADS)
Kuroda, Kazuaki
2015-01-01
Gravitational wave is predicted by Einstein’s general relativity, which conveys the information of source objects in the universe. The detection of the gravitational wave is the direct test of the theory and will be used as new tool to investigate dynamical nature of the universe. However, the effect of the gravitational wave is too tiny to be easily detected. From the first attempt utilizing resonant antenna in the 1960s, efforts of improving antenna sensitivity were continued by applying cryogenic techniques until approaching the quantum limit of sensitivity. However, by the year 2000, resonant antenna had given the way to interferometers. Large projects involving interferometers started in the 1990s, and achieved successful operations by 2010 with an accumulated extensive number of technical inventions and improvements. In this memorial year 2015, we enter the new phase of gravitational-wave detection by the forthcoming operation of the second-generation interferometers. The main focus in this paper is on how advanced techniques have been developed step by step according to scaling the arm length of the interferometer up and the history of fighting against technical noise, thermal noise, and quantum noise is presented along with the current projects, LIGO, Virgo, GEO-HF and KAGRA.
Generation of Gravitational Waves with Nuclear Reactions
Fontana, Giorgio; Baker, Robert M. L. Jr.
2006-01-20
The problem of efficient generation of High Frequency Gravitational Waves (HFGWs) and pulses of Gravitational Radiation might find a reasonably simple solution by employing nuclear matter, especially isomers. A fissioning isomer not only rotates at extremely high frequency ({approx} 3.03x1024 s-1), but is also highly deformed in the first stages of fission (the nucleus is rotating and made asymmetric 'before' fission). Thus one achieves significant impulsive forces (e.g., 3.67x108 N) acting over extremely short time spans (e.g., 3.3x10-22 s). Alternatively, a pulsed particle beam, which could include antimatter, could trigger nuclear reactions and build up a coherent GW as the particles move through a target mass. The usual difficulty with HFGWs generated by nuclear reactions is the small dimensions of their nuclear-reaction volumes, that is, the small moment of inertia and submicroscopic radii of gyration (e.g., 10-16 m) of the nuclear-mass system. Such a difficulty is overcome by utilizing clusters of nuclear material, whose nuclear reactions are in synchronization (through the use of a computer controlled logic system) and are at a large distance apart, e.g., meters, kilometers, etc. The effective radius of gyration of the overall nuclear mass system is enormous and if the quadrupole formalism holds even approximately, then significant HFGW is generated, for example up to 8.5x1010 W to 1.64x1025 W bursts for the transient asymmetrical spinning nucleus case. In this preliminary analysis, possible conceptual designs of reactors suitable for the generation of HFGWs are discussed as well as applications to space technology. In an optimized dual-beam design, GW amplitudes on the order of A {approx} 0.005 are theoretically achieved in the laboratory, which might have interesting general-relativity and nuclear-physics consequences.
New window into stochastic gravitational wave background.
Rotti, Aditya; Souradeep, Tarun
2012-11-30
A stochastic gravitational wave background (SGWB) would gravitationally lens the cosmic microwave background (CMB) photons. We correct the results provided in existing literature for modifications to the CMB polarization power spectra due to lensing by gravitational waves. Weak lensing by gravitational waves distorts all four CMB power spectra; however, its effect is most striking in the mixing of power between the E mode and B mode of CMB polarization. This suggests the possibility of using measurements of the CMB angular power spectra to constrain the energy density (Ω(GW)) of the SGWB. Using current data sets (QUAD, WMAP, and ACT), we find that the most stringent constraints on the present Ω(GW) come from measurements of the angular power spectra of CMB temperature anisotropies. In the near future, more stringent bounds on Ω(GW) can be expected with improved upper limits on the B modes of CMB polarization. Any detection of B modes of CMB polarization above the expected signal from large scale structure lensing could be a signal for a SGWB.
Gravitational waves from an early matter era
Assadullahi, Hooshyar; Wands, David
2009-04-15
We investigate the generation of gravitational waves due to the gravitational instability of primordial density perturbations in an early matter-dominated era which could be detectable by experiments such as laser interferometer gravitational wave observatory (LIGO) and laser interferometer space antenna (LISA). We use relativistic perturbation theory to give analytic estimates of the tensor perturbations generated at second order by linear density perturbations. We find that large enhancement factors with respect to the naive second-order estimate are possible due to the growth of density perturbations on sub-Hubble scales. However very large enhancement factors coincide with a breakdown of linear theory for density perturbations on small scales. To produce a primordial gravitational-wave background that would be detectable with LIGO or LISA from density perturbations in the linear regime requires primordial comoving curvature perturbations on small scales of order 0.02 for advanced LIGO or 0.005 for LISA; otherwise numerical calculations of the nonlinear evolution on sub-Hubble scales are required.
BOOK REVIEW: Gravitational Waves, Volume 1: Theory and Experiments
NASA Astrophysics Data System (ADS)
Poisson, Eric
2008-10-01
discussion is helpful, as it clarifies some of the puzzling aspects of general covariance. Next the treatment becomes more sophisticated: the waves are allowed to propagate in an arbitrary background spacetime, and the energy momentum carried by the wave is identified by the second-order perturbation of the Einstein tensor. In chapter 2 the waves are given a field-theoretic foundation that is less familiar (but refreshing) to a relativist, but would appeal to a practitioner of effective field theories. In an interesting section of chapter 2, the author gives a mass to the (classical) graviton and explores the physical consequences of this proposal. In chapter 3 the author returns to the standard linearized theory and develops the multipolar expansion of the gravitational-wave field in the context of slowly-moving sources; at leading order he obtains the famous quadrupole formula. His treatment is very detailed, and it includes a complete account of symmetric-tracefree tensors and tensorial spherical harmonics. It is, however, necessarily limited to sources with negligible internal gravity. Unfortunately (and this is a familiar complaint of relativists) the author omits to warn the reader of this important limitation. In fact, the chapter opens with a statement of the virial theorem of Newtonian gravity, which may well mislead the reader to believe that the linearized theory can be applied to a system bound by gravitational forces. This misconception is confirmed when, in chapter 4, the author applies the quadrupole formula to gravitationally-bound systems such as an inspiraling compact binary, a rigidly rotating body, and a mass falling toward a black hole. This said, the presentation of these main sources of gravitational waves is otherwise irreproachable, and a wealth of useful information is presented in a clear and lucid manner. For example, the discussion of inspiraling compact binaries includes a derivation of the orbital evolution of circular and eccentric orbits
Articulated Multimedia Physics, Lesson 9, Universal Gravitation.
ERIC Educational Resources Information Center
New York Inst. of Tech., Old Westbury.
As the ninth lesson of the Articulated Multimedia Physics Course, instructional materials relating to universal gravitation are presented in this study guide. The subject is concerned with the quantitative meaning of the law of universal gravitation and its applications in astronomy. The content is arranged in scrambled form, and the use of matrix…
Superconducting Antenna Concept for Gravitational Waves
NASA Astrophysics Data System (ADS)
Gulian, A.; Foreman, J.; Nikoghosyan, V.; Nussinov, S.; Sica, L.; Tollaksen, J.
The most advanced contemporary efforts and concepts for registering gravitational waves are focused on measuring tiny deviations in large arm (kilometers in case of LIGO and thousands of kilometers in case of LISA) interferometers via photons. In this report we discuss a concept for the detection of gravitational waves using an antenna comprised of superconducting electrons (Cooper pairs) moving in an ionic lattice. The major challenge in this approach is that the tidal action of the gravitational waves is extremely weak compared with electromagnetic forces. Any motion caused by gravitational waves, which violates charge neutrality, will be impeded by Coulomb forces acting on the charge carriers (Coulomb blockade) in metals, as well as in superconductors. We discuss a design, which avoids the effects of Coulomb blockade. It exploits two different superconducting materials used in a form of thin wires -"spaghetti." The spaghetti will have a diameter comparable to the London penetration depth, and length of about 1-10 meters. To achieve competitive sensitivity, the antenna would require billions of spaghettis, which calls for a challenging manufacturing technology. If successfully materialized, the response of the antenna to the known highly periodic sources of gravitational radiation, such as the Pulsar in Crab Nebula will result in an output current, detectable by superconducting electronics. The antenna will require deep (0.3K) cryogenic cooling and magnetic shielding. This design may be a viable successor to LISA and LIGO concepts, having the prospect of higher sensitivity, much smaller size and directional selectivity. This concept of compact antenna may benefit also terrestrial gradiometry.
Gravitational waves in the spectral action of noncommutative geometry
Nelson, William; Ochoa, Joseph; Sakellariadou, Mairi
2010-10-15
The spectral triple approach to noncommutative geometry allows one to develop the entire standard model (and supersymmetric extensions) of particle physics from a purely geometry standpoint and thus treats both gravity and particle physics on the same footing. The bosonic sector of the theory contains a modification to Einstein-Hilbert gravity, involving a nonconformal coupling of curvature to the Higgs field and conformal Weyl term (in addition to a nondynamical topological term). In this paper we derive the weak-field limit of this gravitational theory and show that the production and dynamics of gravitational waves are significantly altered. In particular, we show that the graviton contains a massive mode that alters the energy lost to gravitational radiation, in systems with evolving quadrupole moment. We explicitly calculate the general solution and apply it to systems with periodically varying quadrupole moments, focusing, in particular, on the well-known energy loss formula for circular binaries.
Michelson geostationary gravitational wave observatory.
NASA Astrophysics Data System (ADS)
Anderson, A. J.
Studies made during the previous year are outlined. These studies have indicated that a Michelson mm wave interferometer observatory (MGO) operating in geostationary orbit is the best configuration satisfying both current operational and design constraints. It is proposed to study the design of this space laboratory interferometer and to study the inclusion of an inertial transponder in this design.
PREFACE: 8th Edoardo Amaldi Conference on Gravitational Waves
NASA Astrophysics Data System (ADS)
Marka, Zsuzsa; Marka, Szabolcs
2010-04-01
multimessenger approaches to gravitational wave detection also received special attention at the meeting. For the first time in the history of Amaldi conferences, plenary and contributed sessions were held to transfer ideas and experience gained with gravitational wave science inspired education and outreach projects. Additionally, Columbia University faculties working in frontier fields, which currently may not have direct connection to the field of gravitational wave science, gave enthralling presentations in the form of a 'wake-up' lecture series. The meeting also facilitated the exchange of scientific results and new ideas among all members of gravitational wave experiment collaborations and the gravitational wave theory community. Additionally, future directions in gravitational wave detection were discussed in a special session dedicated to the Gravitational Wave International Committee Roadmap. A highly entertaining and inspiring public talk titled "Songs from Space: Black Holes and the Big Bang in Audio" was given by Janna Levin and it attracted over 300 young and old science enthusiasts from and around New York City. This special issue of Classical and Quantum Gravity (Volume 27, Number 8, 2010) is published as the proceedings of Amaldi8. It contains the overview articles by invited plenary speakers, and some of the highlights of the meeting as selected by session chairs and organizers. Other Amaldi8 talks and posters appear in the refereed issue of the electronic Journal of Physics: Conference Series. This issue of CQG and the JPCS issue are electronically linked. The conference organizers gratefully acknowledge the financial support of Columbia University in the City of New York, the International Union of Pure and Applied Physics and the United States National Science Foundation. We would like to thank the Gravitational Wave International Committee for the scientific oversight, the Local Organizing Committee for the program selection, and the session chairs for the
Denoising of gravitational wave signals via dictionary learning algorithms
NASA Astrophysics Data System (ADS)
Torres-Forné, Alejandro; Marquina, Antonio; Font, José A.; Ibáñez, José M.
2016-12-01
Gravitational wave astronomy has become a reality after the historical detections accomplished during the first observing run of the two advanced LIGO detectors. In the following years, the number of detections is expected to increase significantly with the full commissioning of the advanced LIGO, advanced Virgo and KAGRA detectors. The development of sophisticated data analysis techniques to improve the opportunities of detection for low signal-to-noise-ratio events is, hence, a most crucial effort. In this paper, we present one such technique, dictionary-learning algorithms, which have been extensively developed in the last few years and successfully applied mostly in the context of image processing. However, to the best of our knowledge, such algorithms have not yet been employed to denoise gravitational wave signals. By building dictionaries from numerical relativity templates of both binary black holes mergers and bursts of rotational core collapse, we show how machine-learning algorithms based on dictionaries can also be successfully applied for gravitational wave denoising. We use a subset of signals from both catalogs, embedded in nonwhite Gaussian noise, to assess our techniques with a large sample of tests and to find the best model parameters. The application of our method to the actual signal GW150914 shows promising results. Dictionary-learning algorithms could be a complementary addition to the gravitational wave data analysis toolkit. They may be used to extract signals from noise and to infer physical parameters if the data are in good enough agreement with the morphology of the dictionary atoms.
Dynamics of laser interferometric gravitational wave detectors
NASA Astrophysics Data System (ADS)
Rakhmanov, Malik
2000-11-01
Dynamics of fields and mirrors in the new laser interferometric gravitational wave detectors is described. The dynamics of fields is formulated in terms of difference equations, which take into account the large delay due to the light transit time in the interferometer arm cavities. Solutions of these field equations are found in both transient and steady-state regimes. The solutions for fields in the transient regime can be used for the measurement of the parameters of Fabry-Perot cavities. The solutions for fields in the steady-state regime can be used for the analysis of noise performance of Fabry-Perot cavities. The dynamics of the mirrors is described in terms of two normal coordinates: the cavity length and its center of mass. Such dynamics is strongly affected by the radiation pressure of light circulating in the cavity. The forces of radiation pressure are nonlinear and nonconservative. These two effects introduce instabilities and give rise to a violation of conservation of energy for the motion of the suspended mirrors. Analytical calculations and numerical simulations of the dynamics are done with applications to the Laser Interferometer Gravitational-Wave Observatory (LIGO). The dynamics of signal recycling and power recycling interferometers is analyzed using the field equations. The response of the interferometers to the input laser field and motion of its mirrors is calculated. Several basic transfer functions are found. These correspond to either a single or a nested cavity. A nested cavity appears either in the dynamics of the differential mode in signal recycling interferometers or in the dynamics of the common mode of power recycling interferometers. The poles of transfer functions of these nested cavities are found. The response of the interferometers to gravitational waves is described: the analysis is done in the rest frame of a local observer which is a natural coordinate system of the detector. This response is given by the interferometer
Response of interferometric gravitational wave detectors
Finn, Lee Samuel
2009-01-15
The derivation of the response function of an interferometric gravitational wave detector is a paradigmatic calculation in the field of gravitational wave detection. Surprisingly, the standard derivation of the response wave detectors makes several unjustifiable assumptions, both conceptual and quantitative, regarding the coordinate trajectory and coordinate velocity of the null geodesic the light travels along. These errors, which appear to have remained unrecognized for at least 35 years, render the standard derivation inadequate and misleading as an archetype calculation. Here we identify the flaws in the existing derivation and provide, in full detail, a correct derivation of the response of a single-bounce Michelson interferometer to gravitational waves, following a procedure that will always yield correct results; compare it to the standard, but incorrect, derivation; show where the earlier mistakes were made; and identify the general conditions under which the standard derivation will yield correct results. By a fortuitous set of circumstances, not generally so, the final result is the same in the case of Minkowski background spacetime, synchronous coordinates, transverse-traceless gauge metric perturbations, and arm mirrors at coordinate rest.
Simulating Responses of Gravitational-Wave Instrumentation
NASA Technical Reports Server (NTRS)
Armstrong, John; Edlund, Jeffrey; Vallisneri. Michele
2006-01-01
Synthetic LISA is a computer program for simulating the responses of the instrumentation of the NASA/ESA Laser Interferometer Space Antenna (LISA) mission, the purpose of which is to detect and study gravitational waves. Synthetic LISA generates synthetic time series of the LISA fundamental noises, as filtered through all the time-delay-interferometry (TDI) observables. (TDI is a method of canceling phase noise in temporally varying unequal-arm interferometers.) Synthetic LISA provides a streamlined module to compute the TDI responses to gravitational waves, according to a full model of TDI (including the motion of the LISA array and the temporal and directional dependence of the arm lengths). Synthetic LISA is written in the C++ programming language as a modular package that accommodates the addition of code for specific gravitational wave sources or for new noise models. In addition, time series for waves and noises can be easily loaded from disk storage or electronic memory. The package includes a Python-language interface for easy, interactive steering and scripting. Through Python, Synthetic LISA can read and write data files in Flexible Image Transport System (FITS), which is a commonly used astronomical data format.
Pseudospectral method for gravitational wave collapse
NASA Astrophysics Data System (ADS)
Hilditch, David; Weyhausen, Andreas; Brügmann, Bernd
2016-03-01
We present a new pseudospectral code, bamps, for numerical relativity written with the evolution of collapsing gravitational waves in mind. We employ the first-order generalized harmonic gauge formulation. The relevant theory is reviewed, and the numerical method is critically examined and specialized for the task at hand. In particular, we investigate formulation parameters—gauge- and constraint-preserving boundary conditions well suited to nonvanishing gauge source functions. Different types of axisymmetric twist-free moment-of-time-symmetry gravitational wave initial data are discussed. A treatment of the axisymmetric apparent horizon condition is presented with careful attention to regularity on axis. Our apparent horizon finder is then evaluated in a number of test cases. Moving on to evolutions, we investigate modifications to the generalized harmonic gauge constraint damping scheme to improve conservation in the strong-field regime. We demonstrate strong-scaling of our pseudospectral penalty code. We employ the Cartoon method to efficiently evolve axisymmetric data in our 3 +1 -dimensional code. We perform test evolutions of the Schwarzschild spacetime perturbed by gravitational waves and by gauge pulses, both to demonstrate the use of our black-hole excision scheme and for comparison with earlier results. Finally, numerical evolutions of supercritical Brill waves are presented to demonstrate durability of the excision scheme for the dynamical formation of a black hole.
Breaking a dark degeneracy with gravitational waves
Lombriser, Lucas; Taylor, Andy E-mail: ant@roe.ac.uk
2016-03-01
We identify a scalar-tensor model embedded in the Horndeski action whose cosmological background and linear scalar fluctuations are degenerate with the concordance cosmology. The model admits a self-accelerated background expansion at late times that is stable against perturbations with a sound speed attributed to the new field that is equal to the speed of light. While degenerate in scalar fluctuations, self-acceleration of the model implies a present cosmological tensor mode propagation at ∼<95 % of the speed of light with a damping of the wave amplitude that is ∼>5 % less efficient than in general relativity. We show that these discrepancies are endemic to self-accelerated Horndeski theories with degenerate large-scale structure and are tested with measurements of gravitational waves emitted by events at cosmological distances. Hence, gravitational-wave cosmology breaks the dark degeneracy in observations of the large-scale structure between two fundamentally different explanations of cosmic acceleration—a cosmological constant and a scalar-tensor modification of gravity. The gravitational wave event GW150914 recently detected with the aLIGO instruments and its potential association with a weak short gamma-ray burst observed with the Fermi GBM experiment may have provided this crucial measurement.
Tuning advanced gravitational-wave detectors to optimally measure neutron-star merger waves
NASA Astrophysics Data System (ADS)
Stein, Leo
2010-02-01
Next-generation gravitational wave detectors have the potential to bring us astrophysical information in yet unexplored regimes. One of the possibilities is learning about neutron stars' equations of state from the gravitational wave burst of a binary coalescence. Since these events are ``bursty'', one does not have the luxury of time-averaging to improve S/N; one can only hope to do better by ``tuning'' a detector network to have the noise performance which will be most informative about the physics. We present a Bayesian method for optimizing a detector network given a prior distribution of physical parameters which affect the gravitational wave signal. Each detection adds information about the parameter distribution, updating the posterior and the optimal detector configuration. We demonstrate the algorithm with toy signal and detector response models and predict whether tuning Advanced LIGO (via the signal recycling cavity) will be fruitful in accelerating our understanding of neutron stars through their mergers. )
Physics through the 1990s: Gravitation, cosmology and cosmic-ray physics
NASA Technical Reports Server (NTRS)
1986-01-01
The volume contains recommendations for space-and ground-based programs in gravitational physics, cosmology, and cosmic-ray physics. The section on gravitation examines current and planned experimental tests of general relativity; the theory behind, and search for, gravitational waves, including sensitive laser-interferometric tests and other observations; and advances in gravitation theory (for example, incorporating quantum effects). The section on cosmology deals with the big-bang model, the standard model from elementary-particle theory, the inflationary model of the Universe. Computational needs are presented for both gravitation and cosmology. Finally, cosmic-ray physics theory (nucleosynthesis, acceleration models, high-energy physics) and experiment (ground and spaceborne detectors) are discussed.
Detecting Triple Systems with Gravitational Wave Observations
NASA Astrophysics Data System (ADS)
Meiron, Yohai; Kocsis, Bence; Loeb, Abraham
2017-01-01
The Laser Interferometer Gravitational Wave Observatory (LIGO) has recently discovered gravitational waves (GWs) emitted by merging black hole binaries. We examine whether future GW detections may identify triple companions of merging binaries. Such a triple companion causes variations in the GW signal due to: (1) the varying path length along the line of sight during the orbit around the center of mass; (2) relativistic beaming, Doppler, and gravitational redshift; (3) the variation of the “light”-travel time in the gravitational field of the triple companion; and (4) secular variations of the orbital elements. We find that the prospects for detecting a triple companion are the highest for low-mass compact object binaries which spend the longest time in the LIGO frequency band. In particular, for merging neutron star binaries, LIGO may detect a white dwarf or M-dwarf perturber at a signal-to-noise ratio of 8, if it is within 0.4 {R}ȯ distance from the binary and the system is within a distance of 100 Mpc. Stellar mass (supermassive) black hole perturbers may be detected at a factor 5 × (103×) larger separations. Such pertubers in orbit around a merging binary emit GWs at frequencies above 1 mHz detectable by the Laser Interferometer Space Antenna in coincidence.
Interferometer Techniques for Gravitational-Wave Detection
NASA Astrophysics Data System (ADS)
Freise, Andreas; Strain, Kenneth
2010-12-01
Several km-scale gravitational-wave detectors have been constructed world wide. These instruments combine a number of advanced technologies to push the limits of precision length measurement. The core devices are laser interferometers of a new kind; developed from the classical Michelson topology these interferometers integrate additional optical elements, which significantly change the properties of the optical system. Much of the design and analysis of these laser interferometers can be performed using well-known classical optical techniques, however, the complex optical layouts provide a new challenge. In this review we give a textbook-style introduction to the optical science required for the understanding of modern gravitational wave detectors, as well as other high-precision laser interferometers. In addition, we provide a number of examples for a freely available interferometer simulation software and encourage the reader to use these examples to gain hands-on experience with the discussed optical methods.
Silicon mirror suspensions for gravitational wave detectors
NASA Astrophysics Data System (ADS)
Cumming, A. V.; Cunningham, L.; Hammond, G. D.; Haughian, K.; Hough, J.; Kroker, S.; Martin, I. W.; Nawrodt, R.; Rowan, S.; Schwarz, C.; van Veggel, A. A.
2014-01-01
One of the most significant limits to the sensitivity of current, and future, long-baseline interferometric gravitational wave detectors is thermal displacement noise of the test masses and their suspensions. This paper reports results of analytical and experimental studies of the limits to thermal noise performance of cryogenic silicon test mass suspensions set by two constraints on suspension fibre dimensions: the minimum dimensions required to allow conductive cooling for extracting incident laser beam heat deposited in the mirrors; and the minimum dimensions of fibres (set by their tensile strength) which can support test masses of the size envisaged for use in future detectors. We report experimental studies of breaking strength of silicon ribbons, and resulting design implications for the feasibility of suspension designs for future gravitational wave detectors using silicon suspension fibres. We analyse the implication of this study for thermal noise performance of cryogenically cooled silicon suspensions.
Interferometer techniques for gravitational-wave detection
NASA Astrophysics Data System (ADS)
Bond, Charlotte; Brown, Daniel; Freise, Andreas; Strain, Kenneth A.
2016-12-01
Several km-scale gravitational-wave detectors have been constructed worldwide. These instruments combine a number of advanced technologies to push the limits of precision length measurement. The core devices are laser interferometers of a new kind; developed from the classical Michelson topology these interferometers integrate additional optical elements, which significantly change the properties of the optical system. Much of the design and analysis of these laser interferometers can be performed using well-known classical optical techniques; however, the complex optical layouts provide a new challenge. In this review, we give a textbook-style introduction to the optical science required for the understanding of modern gravitational wave detectors, as well as other high-precision laser interferometers. In addition, we provide a number of examples for a freely available interferometer simulation software and encourage the reader to use these examples to gain hands-on experience with the discussed optical methods.
Gravitational waves from the first stars
Sandick, Pearl; Olive, Keith A.; Daigne, Frederic; Vangioni, Elisabeth
2006-05-15
We consider the stochastic background of gravitational waves produced by an early generation of Population III stars coupled with a normal mode of star formation at lower redshift. The computation is performed in the framework of hierarchical structure formation and is based on cosmic star formation histories constrained to reproduce the observed star formation rate at redshift z < or approx. 6, the observed chemical abundances in damped Lyman alpha absorbers and in the intergalactic medium, and to allow for an early reionization of the Universe at z{approx}11 as indicated by the third year results released by WMAP. We find that the normal mode of star formation produces a gravitational wave background which peaks at 300-500 Hz and is within LIGO III sensitivity. The Population III component peaks at lower frequencies (30-100 Hz depending on the model), and could be detected by LIGO III as well as the planned BBO and DECIGO interferometers.
Interferometer techniques for gravitational-wave detection.
Bond, Charlotte; Brown, Daniel; Freise, Andreas; Strain, Kenneth A
2016-01-01
Several km-scale gravitational-wave detectors have been constructed worldwide. These instruments combine a number of advanced technologies to push the limits of precision length measurement. The core devices are laser interferometers of a new kind; developed from the classical Michelson topology these interferometers integrate additional optical elements, which significantly change the properties of the optical system. Much of the design and analysis of these laser interferometers can be performed using well-known classical optical techniques; however, the complex optical layouts provide a new challenge. In this review, we give a textbook-style introduction to the optical science required for the understanding of modern gravitational wave detectors, as well as other high-precision laser interferometers. In addition, we provide a number of examples for a freely available interferometer simulation software and encourage the reader to use these examples to gain hands-on experience with the discussed optical methods.
Gravitational Wave Experiments - Proceedings of the First Edoardo Amaldi Conference
NASA Astrophysics Data System (ADS)
Coccia, E.; Pizzella, G.; Ronga, F.
1995-07-01
The Table of Contents for the full book PDF is as follows: * Foreword * Notes on Edoardo Amaldi's Life and Activity * PART I. INVITED LECTURES * Sources and Telescopes * Sources of Gravitational Radiation for Detectors of the 21st Century * Neutrino Telescopes * γ-Ray Bursts * Space Detectors * LISA — Laser Interferometer Space Antenna for Gravitational Wave Measurements * Search for Massive Coalescing Binaries with the Spacecraft ULYSSES * Interferometers * The LIGO Project: Progress and Prospects * The VIRGO Experiment: Status of the Art * GEO 600 — A 600-m Laser Interferometric Gravitational Wave Antenna * 300-m Laser Interferometer Gravitational Wave Detector (TAMA300) in Japan * Resonant Detectors * Search for Continuous Gravitational Wave from Pulsars with Resonant Detector * Operation of the ALLEGRO Detector at LSU * Preliminary Results of the New Run of Measurements with the Resonant Antenna EXPLORER * Operation of the Perth Cryogenic Resonant-Bar Gravitational Wave Detector * The NAUTILUS Experiment * Status of the AURIGA Gravitational Wave Antenna and Perspectives for the Gravitational Waves Search with Ultracryogenic Resonant Detectors * Ultralow Temperature Resonant-Mass Gravitational Radiation Detectors: Current Status of the Stanford Program * Electromechanical Transducers and Bandwidth of Resonant-Mass Gravitational-Wave Detectors * Fully Numerical Data Analysis for Resonant Gravitational Wave Detectors: Optimal Filter and Available Information * PART II. CONTRIBUTED PAPERS * Sources and Telescopes * The Local Supernova Production * Periodic Gravitational Signals from Galactic Pulsars * On a Possibility of Scalar Gravitational Wave Detection from the Binary Pulsars PSR 1913+16 * Kazan Gravitational Wave Detector “Dulkyn”: General Concept and Prospects of Construction * Hierarchical Approach to the Theory of Detection of Periodic Gravitational Radiation * Application of Gravitational Antennae for Fundamental Geophysical Problems * On
Gravitational-wave detection using multivariate analysis
NASA Astrophysics Data System (ADS)
Adams, Thomas S.; Meacher, Duncan; Clark, James; Sutton, Patrick J.; Jones, Gareth; Minot, Ariana
2013-09-01
Searches for gravitational-wave bursts (transient signals, typically of unknown waveform) require identification of weak signals in background detector noise. The sensitivity of such searches is often critically limited by non-Gaussian noise fluctuations that are difficult to distinguish from real signals, posing a key problem for transient gravitational-wave astronomy. Current noise rejection tests are based on the analysis of a relatively small number of measured properties of the candidate signal, typically correlations between detectors. Multivariate analysis (MVA) techniques probe the full space of measured properties of events in an attempt to maximize the power to accurately classify events as signal or background. This is done by taking samples of known background events and (simulated) signal events to train the MVA classifier, which can then be applied to classify events of unknown type. We apply the boosted decision tree (BDT) MVA technique to the problem of detecting gravitational-wave bursts associated with gamma-ray bursts. We find that BDTs are able to increase the sensitive distance reach of the search by as much as 50%, corresponding to a factor of ˜3 increase in sensitive volume. This improvement is robust against trigger sky position, large sky localization error, poor data quality, and the simulated signal waveforms that are used. Critically, we find that the BDT analysis is able to detect signals that have different morphologies from those used in the classifier training and that this improvement extends to false alarm probabilities beyond the 3σ significance level. These findings indicate that MVA techniques may be used for the robust detection of gravitational-wave bursts with a priori unknown waveform.
Kinks, extra dimensions, and gravitational waves
O'Callaghan, Eimear; Gregory, Ruth
2011-03-01
We investigate in detail the gravitational wave signal from kinks on cosmic (super)strings, including the kinematical effects from the internal extra dimensions. We find that the signal is suppressed, however, the effect is less significant that that for cusps. Combined with the greater incidence of kinks on (super)strings, it is likely that the kink signal offers the better chance for detection of cosmic (super)strings.
Primordial gravitational waves in running vacuum cosmologies
NASA Astrophysics Data System (ADS)
Tamayo, D. A.; Lima, J. A. S.; Alves, M. E. S.; de Araujo, J. C. N.
2017-01-01
We investigate the cosmological production of gravitational waves in a nonsingular flat cosmology powered by a "running vacuum" energy density described by ρΛ ≡ ρΛ(H), a phenomenological expression potentially linked with the renormalization group approach in quantum field theory in curved spacetimes. The model can be interpreted as a particular case of the class recently discussed by Perico et al. (2013) [25] which is termed complete in the sense that the cosmic evolution occurs between two extreme de Sitter stages (early and late time de Sitter phases). The gravitational wave equation is derived and its time-dependent part numerically integrated since the primordial de Sitter stage. The generated spectrum of gravitons is also compared with the standard calculations where an abrupt transition, from the early de Sitter to the radiation phase, is usually assumed. It is found that the stochastic background of gravitons is very similar to the one predicted by the cosmic concordance model plus inflation except at higher frequencies (ν ≳ 100 kHz). This remarkable signature of a "running vacuum" cosmology combined with the proposed high frequency gravitational wave detectors and measurements of the CMB polarization (B-modes) may provide a new window to confront more conventional models of inflation.
Separating Gravitational Wave Signals from Instrument Artifacts
NASA Technical Reports Server (NTRS)
Littenberg, Tyson B.; Cornish, Neil J.
2010-01-01
Central to the gravitational wave detection problem is the challenge of separating features in the data produced by astrophysical sources from features produced by the detector. Matched filtering provides an optimal solution for Gaussian noise, but in practice, transient noise excursions or "glitches" complicate the analysis. Detector diagnostics and coincidence tests can be used to veto many glitches which may otherwise be misinterpreted as gravitational wave signals. The glitches that remain can lead to long tails in the matched filter search statistics and drive up the detection threshold. Here we describe a Bayesian approach that incorporates a more realistic model for the instrument noise allowing for fluctuating noise levels that vary independently across frequency bands, and deterministic "glitch fitting" using wavelets as "glitch templates", the number of which is determined by a trans-dimensional Markov chain Monte Carlo algorithm. We demonstrate the method's effectiveness on simulated data containing low amplitude gravitational wave signals from inspiraling binary black hole systems, and simulated non-stationary and non-Gaussian noise comprised of a Gaussian component with the standard LIGO/Virgo spectrum, and injected glitches of various amplitude, prevalence, and variety. Glitch fitting allows us to detect significantly weaker signals than standard techniques.
Astrophysical calibration of gravitational-wave detectors
NASA Astrophysics Data System (ADS)
Pitkin, M.; Messenger, C.; Wright, L.
2016-03-01
We investigate a method to assess the validity of gravitational-wave detector calibration through the use of gamma-ray bursts as standard sirens. Such signals, as measured via gravitational-wave observations, provide an estimated luminosity distance that is subject to uncertainties in the calibration of the data. If a host galaxy is identified for a given source then its redshift can be combined with current knowledge of the cosmological parameters yielding the true luminosity distance. This will then allow a direct comparison with the estimated value and can validate the accuracy of the original calibration. We use simulations of individual detectable gravitational-wave signals from binary neutron star (BNS) or neutron star-black hole systems, which we assume to be found in coincidence with short gamma-ray bursts, to estimate any discrepancy in the overall scaling of the calibration for detectors in the Advanced LIGO and Advanced Virgo network. We find that the amplitude scaling of the calibration for the LIGO instruments could on average be confirmed to within ˜10 % for a BNS source within 100 Mpc. This result is largely independent of the current detector calibration method and gives an uncertainty that is competitive with that expected in the current calibration procedure. Confirmation of the calibration accuracy to within ˜20 % can be found with BNS sources out to ˜500 Mpc .
Ground-based gravitational-wave observatories
NASA Astrophysics Data System (ADS)
Giaime, Joseph
2017-01-01
After decades of development and recent upgrades, a network of ground-based interferometric gravitational-wave detectors has begun regular operation. Last year LIGO's two detectors ran for ca. 4 months, observing waves emitted during the inspiral and coalescence of pairs of black holes hundreds of megaparsec from Earth. The results from LIGO's first observational run will be described, as will plans and expectations for a larger network to include Virgo in Europe and other ground-based detectors in the coming years.
The Quest for B Modes from Inflationary Gravitational Waves
NASA Astrophysics Data System (ADS)
Kamionkowski, Marc; Kovetz, Ely D.
2016-09-01
The search for the curl component (B mode) in the cosmic microwave background (CMB) polarization induced by inflationary gravitational waves is described. The canonical single-field slow-roll model of inflation is presented, and we explain the quantum production of primordial density perturbations and gravitational waves. It is shown how these gravitational waves then give rise to polarization in the CMB. We then describe the geometric decomposition of the CMB polarization pattern into a curl-free component (E mode) and curl component (B mode) and show explicitly that gravitational waves induce B modes. We discuss the B modes induced by gravitational lensing and by Galactic foregrounds and show how both are distinguished from those induced by inflationary gravitational waves. Issues involved in the experimental pursuit of these B modes are described, and we summarize some of the strategies being pursued. We close with a brief discussion of some other avenues toward detecting/characterizing the inflationary gravitational-wave background.
Relic gravitational waves and extended inflation
NASA Technical Reports Server (NTRS)
Turner, Michael S.; Wilczek, Frank
1990-01-01
In extended inflation, a new version of inflation where the transition from the false-vacuum phase to a radiation-dominated Universe is accomplished by bubble nucleation and percolation, bubble collisions supply a potent-and potentially detectable-source of gravitational waves. The present energy density in relic gravity waves from bubble collisions is expected to be about 10(exp -5) of closure density-many orders of magnitude greater than that of the gravity waves produced by quantum fluctuations. Their characteristic wavelength depends upon the reheating temperature T(sub RH): lambda is approximately 10(exp 4) cm (10(exp 14) GeV/T(sub RH)). If large numbers of black holes are produced, a not implausible outcome, they will evaporate producing comparable amounts of shorter wavelength waves, lambda is approximately 10(exp -6) cm (T(sub RH)/10(exp 14) GeV).
Gravitational wave detection with the solar probe: I. Motivation
NASA Technical Reports Server (NTRS)
Thorne, K. S.
1978-01-01
Questions are posed and answered through discussion of gravitational wave detection with the Solar Probe. Discussed are: (1) what a gravitational wave is; (2) why wave detection is important; (3) what astrophysical information might be learned from these waves; (4) status of attempts to detect these waves; (5) why the Solar Probe is a special mission for detecting these waves; (6) how the Solar Probe's expected sensitivity compares with the strength of predicted gravitational waves; and (7) what gravity wave searchers will do after the Solar Probe.
PREFACE: VII Mexican School on Gravitation and Mathematical Physics
NASA Astrophysics Data System (ADS)
Alcubierre Moya, Miguel; García Compeán, Héctor Hugo; Ureña López, Luis Arturo
2007-07-01
The present collection of papers was presented during the VII Mexican School on Gravitation and Mathematical Physics, which was held in Playa del Carmen, Quintana Roo, México, from 26 November to 2 December 2006. The Mexican School on Gravitation and Mathematical Physics, sponsored by the Mexican Physical Society, started in 1994 with the purpose of discussing and exchanging current ideas in gravitational physics. Each school has been devoted to a particular subject, and on previous occasions these subjects have covered topics such as supergravity, branes, black holes, the early Universe, observational cosmology, and quantum gravity. At the dawn of the XXI Century, General Relativity has finally become a standard tool in our understanding of numerous astrophysical phenomena. At the same time, the new generation of large interferometric gravitational wave detectors that are just beginning operation holds the promise of finally allowing the detection of gravitational waves and opening a new window on the Universe. However, because of the complexity of the Einstein field equations, the modelling of realistic astrophysical systems and gravitational wave sources can only be done using numerical simulations. Because of this, we have dedicated our VII School to the topic of relativistic astrophysics and numerical relativity. As in all our previous Schools, international leaders in the field were invited to give courses and plenary lectures. The school was complemented with more specialized talks presented in parallel sessions, some of which are included in these proceedings. All the contributions in this volume have been refereed, and they represent a sample of the courses, invited talks and contributed talks presented during our VII School. Our deep gratitude goes to all those who contributed to these proceedings, and to making our VII Mexican School a great success. Miguel Alcubierre Moya, Héctor Hugo García Compeán and Luis Arturo Ureña López Editors
Domain walls and gravitational waves in the Standard Model
NASA Astrophysics Data System (ADS)
Krajewski, Tomasz; Lalak, Zygmunt; Lewicki, Marek; Olszewski, Paweł
2016-12-01
We study domain walls which can be created in the Standard Model under the assumption that it is valid up to very high energy scales. We focus on domain walls interpolating between the physical electroweak vacuum and the global minimum appearing at very high field strengths. The creation of the network which ends up in the electroweak vacuum percolating through the Universe is not as difficult to obtain as one may expect, although it requires certain tuning of initial conditions. Our numerical simulations confirm that such domain walls would swiftly decay and thus cannot dominate the Universe. We discuss the possibility of detection of gravitational waves produced in this scenario. We have found that for the standard cosmology the energy density of these gravitational waves is too small to be observed in present and planned detectors.
Intensity of gravitational wave emitted by an oscillating Keplerian binary
NASA Astrophysics Data System (ADS)
Chowdhury, M. N.; Bhuiyan, M. T. H.; Bhuyan, M. D. I.; Faruque, S. B.
2017-02-01
This paper attempts to formulate a way for calculating the intensity of gravitational wave from two point masses in Keplerian circular and elliptic orbits. The intensity is calculated with the assumption that the orbital plane of the binary undergoes small oscillation about the equilibrium x-y plane. This problem is simplification of a physically possible orbit where one of the point masses is spinning whereby the spin-orbit force drives the orbital plane to wobble in a complicated manner. It is shown that the total energy of gravitational wave emitted by the binary in this case is dominated by the parameters which take into account the oscillation of the plane. The results presented are in fact a generalization of the classic results of Landau and Lifshitz.
Extraction of gravitational waves in numerical relativity.
Bishop, Nigel T; Rezzolla, Luciano
2016-01-01
A numerical-relativity calculation yields in general a solution of the Einstein equations including also a radiative part, which is in practice computed in a region of finite extent. Since gravitational radiation is properly defined only at null infinity and in an appropriate coordinate system, the accurate estimation of the emitted gravitational waves represents an old and non-trivial problem in numerical relativity. A number of methods have been developed over the years to "extract" the radiative part of the solution from a numerical simulation and these include: quadrupole formulas, gauge-invariant metric perturbations, Weyl scalars, and characteristic extraction. We review and discuss each method, in terms of both its theoretical background as well as its implementation. Finally, we provide a brief comparison of the various methods in terms of their inherent advantages and disadvantages.
Extraction of gravitational waves in numerical relativity
NASA Astrophysics Data System (ADS)
Bishop, Nigel T.; Rezzolla, Luciano
2016-12-01
A numerical-relativity calculation yields in general a solution of the Einstein equations including also a radiative part, which is in practice computed in a region of finite extent. Since gravitational radiation is properly defined only at null infinity and in an appropriate coordinate system, the accurate estimation of the emitted gravitational waves represents an old and non-trivial problem in numerical relativity. A number of methods have been developed over the years to "extract" the radiative part of the solution from a numerical simulation and these include: quadrupole formulas, gauge-invariant metric perturbations, Weyl scalars, and characteristic extraction. We review and discuss each method, in terms of both its theoretical background as well as its implementation. Finally, we provide a brief comparison of the various methods in terms of their inherent advantages and disadvantages.
Doppler-cancelled response to VLF gravitational waves
NASA Technical Reports Server (NTRS)
Caporali, A.
1981-01-01
The interaction of long periodic gravitational waves with a three link microwave system known as the Doppler Cancelling System is discussed. This system, which was developed for a gravitational redshift experiment, uses one-way and two-way Doppler informatin to construct the beat signal of two reference oscillators moving with respect to each other. The geometric optics approximation is used to derive the frequency shift produced on a light signal propagating in a gravitational wave space-time. The signature left on the Doppler-cancelled beat by burst and continuous gravitational waves is analyzed. A comparison is made between the response to gravitational waves of the Doppler Cancelling System and that of a Doppler tracking system which employs two-way, round-trip radio waves. A three-fold repetition of the gravitational wave form is found to be a common feature of the response functions of both systems. These two functions otherwise exhibit interesting differences.
(abstract) OMEGA: A Gravitational Wave MIDEX Mission
NASA Technical Reports Server (NTRS)
Hellings, Ronald W.
1996-01-01
Among the low frequency (LF) gravitational wave sources that are of astronomical interest are white dwarf binaries, neutron star binaries, massive black hole binaries, and compact stars spiralling into massive black holes. A mission to detect these sources has been proposed to NASA as a possible member of its low-cost, near-term MIDEX mission series. This mission utilizes six tiny miniprobes in high Earth orbit to produce a sensitive Michelson interferometer with million kilometer arms, yielding a strain sensitivity below 10^{-21} at periods longer than a hundred seconds. At this sensitivity, known binary stars will be seen and plausible unknown massive black hole events will be searched for.
Astronomers Get New Tools for Gravitational-Wave Detection
NASA Astrophysics Data System (ADS)
2010-01-01
exclaimed. "Fermi showed us where to look." "This is a huge help in our effort to use millisecond pulsars to detect gravitational waves," Ransom said. The more such pulsars scientists can find and observe over time, the more likely they are to detect gravitational waves, he explained. He said that astronomers now have barely enough millisecond pulsars to make a convincing gravitational-wave detection. "With Fermi guiding the way, though, we can change that picture quickly," Ray said. "We've just started to follow up on the objects located by Fermi, and have many more to go, with a great success rate so far," he added. Ransom, along with his colleague Mallory Roberts of Eureka Scientific, used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to find eight of the 17 new pulsars. The scientists announced their discoveries at the American Astronomical Society's meeting in Washington, DC. Pulsars are neutron stars -- the dense cores left after a massive star has exploded as a supernova. About as large as a medium-sized city, these neutron stars have strong magnetic fields that channel lighthouse-like beams of radio waves that sweep through space as the star rotates. When such a beam strikes the Earth, radio telescopes can detect the strong radio waves. As they age, pulsars slow their rotation rates. However, if the pulsar is part of a binary-star system and can draw in material from its companion, its rotation can be sped up. When the neutron star has been sped up to rotate hundreds of times a second, it is called a millisecond pulsar. In addition to helping scientists detect gravitational waves, study of millisecond pulars also can yield important new information about other effects of General Relativity and about fundamental particle physics. "This new ability to find many more millisecond pulsars really is a treasure chest that can yield many valuable gems of scientific discovery," Ransom said.
GravEn: software for the simulation of gravitational wave detector network response
NASA Astrophysics Data System (ADS)
Stuver, Amber L.; Finn, Lee Samuel
2006-10-01
Physically motivated gravitational wave signals are needed in order to study the behaviour and efficacy of different data analysis methods seeking their detection. GravEn, short for Gravitational-wave Engine, is a MATLAB® software package that simulates the sampled response of a gravitational wave detector to incident gravitational waves. Incident waves can be specified in a data file or chosen from among a group of pre-programmed types commonly used for establishing the detection efficiency of analysis methods used for LIGO data analysis. Every aspect of a desired signal can be specified, such as start time of the simulation (including inter-sample start times), wave amplitude, source orientation to line of sight, location of the source in the sky, etc. Supported interferometric detectors include LIGO, GEO, Virgo and TAMA.
Low-frequency gravitational-wave science frontiers
NASA Astrophysics Data System (ADS)
Hughes, Scott
2017-01-01
With LIGO detecting stellar mass black holes and (soon) other stellar mass compact objects, and with LISA Pathfinder demonstrating important elements of the technology needed to fly a gravitational-wave antenna in space, the case for a low-frequency, space-based gravitational-wave detector - LISA - is stronger than ever. In this talk, I will survey the landscape of low-frequency gravitational-wave astronomy. The LISA frequency band from afew ×10-5 Hz to about 1 Hz is one which is rich with known sources whose measurement will enable new astronomical and physical measurements of important systems. It is also a band with great potential discovery space. In this talk, I will survey the known knowns and known unknowns in the LISA band, describing the frontiers that we can study in advance of the mission, and the frontiers that LISA measurements will unveil. I will also talk about the possible unknown unknowns where surprising discoveries may lurk.
Tuning up for Gravitational Wave Detection in Accreting Neutron Stars
NASA Astrophysics Data System (ADS)
Galloway, Duncan; Steeghs, Danny; Ransom, Scott
Rapidly-rotating neutron stars are the only candidates for persistent gravitational wave emis-sion, for which a targeted search can be performed based on the spin period measured from electromagnetic (e.g. radio and X-ray) observations. Apart from the expected weakness of the emission, the principal difficulty for such searches is the lack of precision in measurements of the spin as well as the other physical parameters of the system. I present a pilot program of optical and infra-red observations of the stellar counterparts to X-ray bright accreting neutron stars, in order to measure (or improve the precision of) the binary parameters. These measurements will allow optimisation of future gravitational wave searches, and will also facilitate searches of the extensive X-ray timing data from NASA's Rossi X-ray Timing Explorer, to measure the spin frequency (for those systems where it is not precisely known). Observations such as these will provide the best possible chance for detecting the gravitational wave emission from these systems.
Probing a classically conformal B -L model with gravitational waves
NASA Astrophysics Data System (ADS)
Jinno, Ryusuke; Takimoto, Masahiro
2017-01-01
We study the cosmological history of the classical conformal B -L gauge extension of the standard model, in which the physical scales are generated via the Coleman-Weinberg-type symmetry breaking. In particular, we consider the thermal phase transition of the U (1 )B -L symmetry in the early Universe and resulting gravitational wave production. Due to the classical conformal invariance, the phase transition tends to be a first-order one with ultra-supercooling, which enhances the strength of the produced gravitational waves. We show that, requiring (1) U (1 )B -L is broken after the reheating, (2) the B -L gauge coupling does not blow up below the Planck scale, and (3) the thermal phase transition completes in almost all the patches in the Universe, the gravitational wave spectrum can be as large as ΩGW˜10-8 at the frequency f ˜0.01 - 1 Hz for some model parameters, and a vast parameter region can be tested by future interferometer experiments.
The Data Analysis in Gravitational Wave Detection
NASA Astrophysics Data System (ADS)
Xiao-ge, Wang; Lebigot, Eric; Zhi-hui, Du; Jun-wei, Cao; Yun-yong, Wang; Fan, Zhang; Yong-zhi, Cai; Mu-zi, Li; Zong-hong, Zhu; Jin, Qian; Cong, Yin; Jian-bo, Wang; Wen, Zhao; Yang, Zhang; Blair, David; Li, Ju; Chun-nong, Zhao; Lin-qing, Wen
2017-01-01
Gravitational wave (GW) astronomy based on the GW detection is a rising interdisciplinary field, and a new window for humanity to observe the universe, followed after the traditional astronomy with the electromagnetic waves as the detection means, it has a quite important significance for studying the origin and evolution of the universe, and for extending the astronomical research field. The appearance of laser interferometer GW detector has opened a new era of GW detection, and the data processing and analysis of GWs have already been developed quickly around the world, to provide a sharp weapon for the GW astronomy. This paper introduces systematically the tool software that commonly used for the data analysis of GWs, and discusses in detail the basic methods used in the data analysis of GWs, such as the time-frequency analysis, composite analysis, pulsar timing analysis, matched filter, template, χ2 test, and Monte-Carlo simulation, etc.
Gravitational wave background from rotating neutron stars
NASA Astrophysics Data System (ADS)
Rosado, Pablo A.
2012-11-01
The background of gravitational waves produced by the ensemble of rotating neutron stars (which includes pulsars, magnetars, and gravitars) is investigated. A formula for Ω(f) (a function that is commonly used to quantify the background, and is directly related to its energy density) is derived, without making the usual assumption that each radiating system evolves on a short time scale compared to the Hubble time; the time evolution of the systems since their formation until the present day is properly taken into account. Moreover, the formula allows one to distinguish the different parts of the background: the unresolvable (which forms a stochastic background or confusion noise, since the waveforms composing it cannot be either individually observed or subtracted out of the data of a detector) and the resolvable. Several estimations of the background are obtained, for different assumptions on the parameters that characterize neutron stars and their population. In particular, different initial spin period distributions lead to very different results. For one of the models, with slow initial spins, the detection of the background by present or planned detectors can be rejected. However, other models do predict the detection of the background, that would be unresolvable, by the future ground-based gravitational wave detector ET. A robust upper limit for the background of rotating neutron stars is obtained; it does not exceed the detection threshold of two cross-correlated Advanced LIGO interferometers. If gravitars exist and constitute more than a few percent of the neutron star population, then they produce an unresolvable background that could be detected by ET. Under the most reasonable assumptions on the parameters characterizing a neutron star, the background is too faint to be detected. Previous papers have suggested neutron star models in which large magnetic fields (like the ones that characterize magnetars) induce big deformations in the star, which
Einstein's Symphony: A Gravitational Wave Voyage Through Space and Time
NASA Astrophysics Data System (ADS)
Shapiro Key, Joey; Yunes, Nico; Grimberg, Irene
2015-01-01
Einstein's Symphony: A Gravitational Wave Voyage Through Space and Time is a gravitational wave astronomy planetarium show in production by a collaboration of scientists, filmmakers, and artisits from the Center for Gravitational Wave Astonomy (CGWA) at the University of Texas at Brownsville (UTB) and Montana State University (MSU). The project builds on the success of the interdisciplinary Celebrating Einstein collaboration. The artists and scientists who created the A Shout Across Time original film and the Black (W)hole immersive art installation for Celebrating Einstein are teaming with the Museum of the Rockies Taylor Planetarium staff and students to create a new full dome Digistar planetarium show that will be freely and widely distributed to planetaria in the US and abroad. The show uses images and animations filmed and collected for A Shout Across Time and for Black (W)hole as well as new images and animations and a new soundtrack composed and produced by the MSU School of Music to use the full capability of planetarium sound systems. The planetarium show will be narrated with ideas drawn from the Celebrating Einstein danced lecture on gravitational waves that the collaboration produced. The combination of products, resources, and team members assembled for this project allows us to create an original planetarium show for a fraction of the cost of a typical show. In addition, STEM education materials for G6-12 students and teachers will be provided to complement and support the show. This project is supported by the Texas Space Grant Consortium (TSGC), Montana Space Grant Consortium (MSGC), and the American Physical Society (APS).
Can JWST Follow Up on Gravitational-Wave Detections?
NASA Astrophysics Data System (ADS)
Kohler, Susanna
2016-02-01
Bitten by the gravitational-wave bug? While we await Thursdays press conference, heres some food for thought: if LIGO were able to detect gravitational waves from compact-object mergers, how could we follow up on the detections? A new study investigates whether the upcoming James Webb Space Telescope (JWST) will be able to observe electromagnetic signatures of some compact-object mergers.Hunting for MergersStudying compact-object mergers (mergers of black holes and neutron stars) can help us understand a wealth of subjects, like high-energy physics, how matter behaves at nuclear densities, how stars evolve, and how heavy elements in the universe were created.The Laser Interferometer Gravitational-Wave Observatory (LIGO) is searching for the signature ripples in spacetime identifying these mergers, but gravitational waves are squirrelly: LIGO will only be able to localize wave sources to tens of square degrees. If we want to find out more about any mergers LIGO discovers in gravitational waves, well need a follow-up search for electromagnetic counterparts with other observatories.The Kilonova KeyOne possible electromagnetic counterpart is kilonovae, explosions that can be produced during a merger of a binary neutron star or a neutron starblack hole system. If the neutron star is disrupted during the merger, some of the hot mass is flung outward and shines brightly by radioactive decay.Kilonovae are especially promising as electromagnetic counterparts to gravitational waves for three reasons:They emit isotropically, so the number of observable mergers isnt limited by relativistic beaming.They shine for a week, giving follow-up observatories time to search for them.The source location can beeasily recovered.The only problem? We dont currently have any sensitive survey instruments in the near-infrared band (where kilonova emission peaks) that can provide coverage over tens of square degrees. Luckily, we will soon have just the thing: JWST, launching in 2018!JWSTs
The next detectors for gravitational wave astronomy
NASA Astrophysics Data System (ADS)
Blair, David; Ju, Li; Zhao, ChunNong; Wen, LinQing; Miao, HaiXing; Cai, RongGen; Gao, JiangRui; Lin, XueChun; Liu, Dong; Wu, Ling-An; Zhu, ZongHong; Hammond, Giles; Paik, Ho Jung; Fafone, Viviana; Rocchi, Alessio; Blair, Carl; Ma, YiQiu; Qin, JiaYi; Page, Michael
2015-12-01
This paper focuses on the next detectors for gravitational wave astronomy which will be required after the current ground based detectors have completed their initial observations, and probably achieved the first direct detection of gravitational waves. The next detectors will need to have greater sensitivity, while also enabling the world array of detectors to have improved angular resolution to allow localisation of signal sources. Sect. 1 of this paper begins by reviewing proposals for the next ground based detectors, and presents an analysis of the sensitivity of an 8 km armlength detector, which is proposed as a safe and cost-effective means to attain a 4-fold improvement in sensitivity. The scientific benefits of creating a pair of such detectors in China and Australia is emphasised. Sect. 2 of this paper discusses the high performance suspension systems for test masses that will be an essential component for future detectors, while sect. 3 discusses solutions to the problem of Newtonian noise which arise from fluctuations in gravity gradient forces acting on test masses. Such gravitational perturbations cannot be shielded, and set limits to low frequency sensitivity unless measured and suppressed. Sects. 4 and 5 address critical operational technologies that will be ongoing issues in future detectors. Sect. 4 addresses the design of thermal compensation systems needed in all high optical power interferometers operating at room temperature. Parametric instability control is addressed in sect. 5. Only recently proven to occur in Advanced LIGO, parametric instability phenomenon brings both risks and opportunities for future detectors. The path to future enhancements of detectors will come from quantum measurement technologies. Sect. 6 focuses on the use of optomechanical devices for obtaining enhanced sensitivity, while sect. 7 reviews a range of quantum measurement options.
Gravitational wave astronomy: needle in a haystack.
Cornish, Neil J
2013-02-13
A worldwide array of highly sensitive ground-based interferometers stands poised to usher in a new era in astronomy with the first direct detection of gravitational waves. The data from these instruments will provide a unique perspective on extreme astrophysical objects, such as neutron stars and black holes, and will allow us to test Einstein's theory of gravity in the strong field, dynamical regime. To fully realize these goals, we need to solve some challenging problems in signal processing and inference, such as finding rare and weak signals that are buried in non-stationary and non-Gaussian instrument noise, dealing with high-dimensional model spaces, and locating what are often extremely tight concentrations of posterior mass within the prior volume. Gravitational wave detection using space-based detectors and pulsar timing arrays bring with them the additional challenge of having to isolate individual signals that overlap one another in both time and frequency. Promising solutions to these problems will be discussed, along with some of the challenges that remain.
Astrophysical Model Selection in Gravitational Wave Astronomy
NASA Technical Reports Server (NTRS)
Adams, Matthew R.; Cornish, Neil J.; Littenberg, Tyson B.
2012-01-01
Theoretical studies in gravitational wave astronomy have mostly focused on the information that can be extracted from individual detections, such as the mass of a binary system and its location in space. Here we consider how the information from multiple detections can be used to constrain astrophysical population models. This seemingly simple problem is made challenging by the high dimensionality and high degree of correlation in the parameter spaces that describe the signals, and by the complexity of the astrophysical models, which can also depend on a large number of parameters, some of which might not be directly constrained by the observations. We present a method for constraining population models using a hierarchical Bayesian modeling approach which simultaneously infers the source parameters and population model and provides the joint probability distributions for both. We illustrate this approach by considering the constraints that can be placed on population models for galactic white dwarf binaries using a future space-based gravitational wave detector. We find that a mission that is able to resolve approximately 5000 of the shortest period binaries will be able to constrain the population model parameters, including the chirp mass distribution and a characteristic galaxy disk radius to within a few percent. This compares favorably to existing bounds, where electromagnetic observations of stars in the galaxy constrain disk radii to within 20%.
An Atomic Gravitational Wave Interferometric Sensor (AGIS)
Dimopoulos, Savas; Graham, Peter W.; Hogan, Jason M.; Kasevich, Mark A.; Rajendran, Surjeet; /SLAC /Stanford U., Phys. Dept.
2008-08-01
We propose two distinct atom interferometer gravitational wave detectors, one terrestrial and another satellite-based, utilizing the core technology of the Stanford 10m atom interferometer presently under construction. Each configuration compares two widely separated atom interferometers run using common lasers. The signal scales with the distance between the interferometers, which can be large since only the light travels over this distance, not the atoms. The terrestrial experiment with baseline {approx} 1 km can operate with strain sensitivity {approx} 10{sup -19}/{radical}Hz in the 1 Hz-10 Hz band, inaccessible to LIGO, and can detect gravitational waves from solar mass binaries out to megaparsec distances. The satellite experiment with baseline {approx} 1000 km can probe the same frequency spectrum as LISA with comparable strain sensitivity {approx} 10{sup -20}/{radical}Hz. The use of ballistic atoms (instead of mirrors) as inertial test masses improves systematics coming from vibrations, acceleration noise, and significantly reduces spacecraft control requirements. We analyze the backgrounds in this configuration and discuss methods for controlling them to the required levels.
X ray timing observations and gravitational physics
NASA Technical Reports Server (NTRS)
Michelson, Peter F.; Wood, Kent S.
1989-01-01
Photon-rich x ray observations on bright compact galactic sources will make it possible to detect many fast processes that may occur in these systems on millisecond and submillisecond timescales. Many of these processes are of direct relevance to gravitational physics because they arise in regions of strong gravity near neutron stars and black holes where the dynamical timescales for compact objects of stellar mass are milliseconds. To date, such observations have been limited by the detector area and telemetry rates available. However, instruments such as the proposed X ray Large Array (XLA) would achieve collecting areas of about 100 sq m. This instrument has been described elsewhere (Wood and Michelson 1988) and was the subject of a recent prephase A feasibility study at Marshall Space Flight Center. Observations with an XLA class instrument will directly impact five primary areas of astrophysics research: the attempt to detect gravitational radiation, the study of black holes, the physics of mass accretion onto compact objects, the structure of neutron stars and nuclear matter, and the characterization of dark matter in the universe. Those observations are discussed that are most directly relevant to gravitational physics: the search for millisecond x ray pulsars that are potential sources of continuous gravitational radiation; and the use of x ray timing observations to probe the physical conditions in extreme relativistic regions of space near black holes, both stellar-sized and supermassive.
Phase Measurement System for Gravitational Wave Detection
NASA Astrophysics Data System (ADS)
Klipstein, William
We propose to advance the maturity of the LISA Phasemeter based on our recent experience developing a flight Phasemeter for the Laser Ranging Interferometer (LRI) on NASA's GRACE Follow-On mission. Our three main objectives are to: 1) incorporate the flight GRACE Follow-on LRI phasemeter developments into the TRL4 LISA design used extensively in our interferometer testbed; 2) evaluate the LRI Phasemeter against LISA's more stringent requirements in order to identify required design changes; 3) advance the design maturity of the LISA phasemeter through an architecture study to maintain the viability of the Phasemeter as a contribution to ESA's L3 gravitational wave mission. NASA intends to partner in the European Space Agency's (ESA) Gravitational-Wave detection mission, selected for the L3 mission to launch in 2034. This is expected to be a LISA-like mission with the two enabling LISA technologies: 1. a drag-free system to mitigate or measure non-gravitational forces on the spacecraft, 2. an interferometric measure¬ment system with precision phasemeters to measure picometer variations over the million kilometer separation between the spacecraft. To validate the key technologies of the drag-free system, the ESA LISA Pathfinder (LPF) mission is currently demonstrating a gravitational reference sensor (GRS) and microNewton thrusters in space. While LPF has an on-board interferometer to measure proof- mass motion with respect to the spacecraft, the LPF interferometer does not test the interspacecraft laser interferometry needed for a LISA-like mission. To validate the key technologies of the LISA interferometric measurement, the JPL LISA Phase Measurement Team has studied and developed a prototype LISA phase measurement system. This phase measurement system has also been adapted for a demonstration mission, albeit in a different arena. GRACE Follow-Ons Laser Ranging Interferometer (LRI), due to launch in late 2017, will make LISA-like inter-spacecraft interferometric
Helicity-rotation-gravity coupling for gravitational waves
Ramos, Jairzinho; Mashhoon, Bahram
2006-04-15
The consequences of spin-rotation-gravity coupling are worked out for linear gravitational waves. The coupling of helicity of the wave with the rotation of a gravitational-wave antenna is investigated and the resulting modifications in the Doppler effect and aberration are pointed out for incident high-frequency gravitational radiation. Extending these results to the case of a gravitomagnetic field via the gravitational Larmor theorem, the rotation of linear polarization of gravitational radiation propagating in the field of a rotating mass is studied. It is shown that in this case the linear polarization state rotates by twice the Skrotskii angle as a consequence of the spin-2 character of linear gravitational waves.
Black Hole Coalescence: The Gravitational Wave Driven Phase
NASA Technical Reports Server (NTRS)
Schnittman, Jeremy D.
2011-01-01
When two supermassive black holes (SMBHS) approach within 1-10 mpc, gravitational wave (GW) losses begin to dominate the evolution of the binary, pushing the system to merge in a relatively small time. During this final inspiral regime, the system will emit copious energy in GWs, which should be directly detectable by pulsar timing arrays and space-based interferometers. At the same time, any gas or stars in the immediate vicinity of the merging 5MBHs can get heated and produce bright electromagnetic (EM) counterparts to the GW signals. We present here a number of possible mechanisms by which simultaneous EM and GW signals will yield valuable new information about galaxy evolution, accretion disk dynamics, and fundamental physics in the most extreme gravitational fields.
Gravitational wave astronomy— astronomy of the 21st century
NASA Astrophysics Data System (ADS)
Dhurandhar, S. V.
2011-12-01
An enigmatic prediction of Einstein's general theory of relativity is gravitational waves. With the observed decay in the orbit of the Hulse-Taylor binary pulsar agreeing within a fraction of a percent with the theoretically computed decay from Einstein's theory, the existence of gravitational waves was firmly established. Currently there is a worldwide effort to detect gravitational waves with inteferometric gravitational wave observatories or detectors and several such detectors have been built or are being built. The initial detectors have reached their design sensitivities and now the effort is on to construct advanced detectors which are expected to detect gravitational waves from astrophysical sources. The era of gravitational wave astronomy has arrived. This article describes the worldwide effort which includes the effort on the Indian front— the IndIGO project —, the principle underlying interferometric detectors both on ground and in space, the principal noise sources that plague such detectors, the astrophysical sources of gravitational waves that one expects to detect by these detectors and some glimpse of the data analysis methods involved in extracting the very weak gravitational wave signals from detector noise.
Gravitational wave astronomy - astronomy of the 21st century
NASA Astrophysics Data System (ADS)
Dhurandhar, S. V.
2011-03-01
An enigmatic prediction of Einstein's general theory of relativity is gravitational waves. With the observed decay in the orbit of the Hulse-Taylor binary pulsar agreeing within a fraction of a percent with the theoretically computed decay from Einstein's theory, the existence of gravitational waves was firmly established. Currently there is a worldwide effort to detect gravitational waves with inteferometric gravitational wave observatories or detectors and several such detectors have been built or being built. The initial detectors have reached their design sensitivities and now the effort is on to construct advanced detectors which are expected to detect gravitational waves from astrophysical sources. The era of gravitational wave astronomy has arrived. This article describes the worldwide effort which includes the effort on the Indian front - the IndIGO project -, the principle underlying interferometric detectors both on ground and in space, the principal noise sources that plague such detectors, the astrophysical sources of gravitational waves that one expects to detect by these detectors and some glimpse of the data analysis methods involved in extracting the very weak gravitational wave signals from detector noise.
Optimizing Vetoes for Gravitational-wave Transient Searches
NASA Technical Reports Server (NTRS)
Essick, R.; Blackburn, Lindy L.; Katsavounidis, E.
2014-01-01
Interferometric gravitational-wave detectors like LIGO, GEO600 and Virgo record a surplus of information above and beyond possible gravitational-wave events. These auxiliary channels capture information about the state of the detector and its surroundings which can be used to infer potential terrestrial noise sources of some gravitational-wave-like events. We present an algorithm addressing the ordering (or equivalently optimizing) of such information from auxiliary systems in gravitational-wave detectors to establish veto conditions in searches for gravitational-wave transients. The procedure was used to identify vetoes for searches for unmodelled transients by the LIGO and Virgo collaborations during their science runs from 2005 through 2007. In this work we present the details of the algorithm; we also use a limited amount of data from LIGO's past runs in order to examine the method, compare it with other methods, and identify its potential to characterize the instruments themselves. We examine the dependence of Receiver Operating Characteristic curves on the various parameters of the veto method and the implementation on real data. We find that the method robustly determines important auxiliary channels, ordering them by the apparent strength of their correlations to the gravitational-wave channel. This list can substantially reduce the background of noise events in the gravitational-wave data. In this way it can identify the source of glitches in the detector as well as assist in establishing confidence in the detection of gravitational-wave transients.
Parameter estimation of gravitational wave compact binary coalescences
NASA Astrophysics Data System (ADS)
Haster, Carl-Johan; LIGO Scientific Collaboration Collaboration
2017-01-01
The first detections of gravitational waves from coalescing binary black holes have allowed unprecedented inference on the astrophysical parameters of such binaries. Given recent updates in detector capabilities, gravitational wave model templates and data analysis techniques, in this talk I will describe the prospects of parameter estimation of compact binary coalescences during the second observation run of the LIGO-Virgo collaboration.
Merger of binary neutron stars: Gravitational waves and electromagnetic counterparts
NASA Astrophysics Data System (ADS)
Shibata, Masaru
2016-12-01
Late inspiral and merger phases of binary neutron stars are the valuable new experimental fields for exploring nuclear physics because (i) gravitational waves from them will bring information for the neutron-star equation of state and (ii) the matter ejected after the onset of the merger could be the main site for the r-process nucleosynthesis. We will summarize these aspects of the binary neutron stars, describing the current understanding for the merger process of binary neutron stars that has been revealed by numerical-relativity simulations.
Directed search for continuous gravitational waves from the Galactic center
NASA Astrophysics Data System (ADS)
Aasi, J.; Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Accadia, T.; Acernese, F.; Adams, C.; Adams, T.; Adhikari, R. X.; Affeldt, C.; Agathos, M.; Aggarwal, N.; Aguiar, O. D.; Ajith, P.; Allen, B.; Allocca, A.; Amador Ceron, E.; Amariutei, D.; Anderson, R. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J.; Ast, S.; 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.; Barker, D.; Barnum, S. H.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J.; Bauchrowitz, J.; Bauer, Th. S.; Bebronne, M.; Behnke, B.; Bejger, M.; Beker, M. G.; Bell, A. S.; Bell, C.; Belopolski, I.; Bergmann, G.; Berliner, J. M.; Bertolini, A.; Bessis, D.; Betzwieser, J.; Beyersdorf, P. T.; Bhadbhade, T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Bitossi, M.; Bizouard, M. A.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Blom, M.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogan, C.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Bose, S.; Bosi, L.; Bowers, J.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brannen, C. A.; Brau, J. E.; Breyer, J.; Briant, T.; Bridges, D. O.; Brillet, A.; Brinkmann, M.; Brisson, V.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brückner, F.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; 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.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; 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, D. E.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Colombini, M.; Constancio, M., Jr.; Conte, A.; Conte, R.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; 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.; Daudert, B.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; Dayanga, T.; De Rosa, R.; Debreczeni, G.; Degallaix, J.; Del Pozzo, W.; Deleeuw, E.; Deléglise, S.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; DeRosa, R.; DeSalvo, R.; Dhurandhar, S.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Díaz, M.; Dietz, A.; Dmitry, K.; Donovan, F.; Dooley, K. L.; Doravari, S.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dumas, J.-C.; Dwyer, S.; Eberle, T.; Edwards, M.; Effler, A.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Endrőczi, G.; Essick, R.; Etzel, T.; Evans, K.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fang, Q.; Farr, B.; Farr, W.; Favata, M.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Ferrante, I.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fisher, R.; Flaminio, R.; Foley, E.; Foley, S.; Forsi, E.; Forte, L. A.; Fotopoulos, N.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, M.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fujimoto, M.-K.; Fulda, P.; Fyffe, M.; Gair, J.; Gammaitoni, L.; Garcia, J.; Garufi, F.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; Gergely, L.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Giazotto, A.; Gil-Casanova, S.; Gill, C.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Griffo, C.; Grote, H.; Grover, K.; Grunewald, S.; Guidi, G. M.; Guido, C.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hall, B.; Hall, E.; Hammer, D.; Hammond, G.; Hanke, M.; 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.; Heidmann, A.; Heintze, M.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Holtrop, M.; Hong, T.; Hooper, S.; Horrom, T.; Hosken, D. J.; Hough, J.; Howell, E. J.; Hu, Y.; Hua, Z.; Huang, V.; Huerta, E. A.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Iafrate, J.; Ingram, D. R.; Inta, R.; Isogai, T.; Ivanov, A.; Iyer, B. R.; Izumi, K.; Jacobson, M.; James, E.; Jang, H.; Jang, Y. J.; Jaranowski, P.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kasprzack, M.; Kasturi, R.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kaufman, K.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kéfélian, F.; Keitel, D.; Kelley, D. B.; Kells, W.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, B. K.; Kim, C.; Kim, K.; Kim, N.; Kim, W.; 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.; Kremin, A.; Kringel, V.; Krishnan, B.; Królak, A.; Kucharczyk, C.; Kudla, S.; Kuehn, G.; Kumar, A.; Kumar, P.; Kumar, R.; Kurdyumov, R.; Kwee, P.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Le Roux, A.; Leaci, P.; Lebigot, E. O.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J.; Lee, J.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levine, B.; Lewis, J. B.; Lhuillier, V.; Li, T. G. F.; Lin, A. C.; Littenberg, T. B.; Litvine, V.; Liu, F.; Liu, H.; Liu, Y.; Liu, Z.; Lloyd, D.; Lockerbie, N. A.; Lockett, V.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Luan, J.; Lubinski, M. J.; Lück, H.; Lundgren, A. P.; Macarthur, J.; Macdonald, E.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-Sandoval, F.; Mageswaran, M.; Mailand, K.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Manca, G. M.; Mandel, I.; Mandic, V.; Mangano, V.; 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.; May, G.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Meier, T.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Michel, C.; Mikhailov, E. E.; Milano, L.; Miller, J.; Minenkov, Y.; Mingarelli, C. M. F.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Mohan, M.; Mohapatra, S. R. P.; Mokler, F.; Moraru, D.; Moreno, G.; Morgado, N.; Mori, T.; 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.; Nash, T.; Naticchioni, L.; Nayak, R.; Necula, V.; Neri, I.; Newton, G.; Nguyen, T.; Nishida, E.; Nishizawa, A.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E.; Nuttall, L. K.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oppermann, P.; O'Reilly, B.; Ortega Larcher, W.; O'Shaughnessy, R.; Osthelder, C.; Ottaway, D. J.; Ottens, R. S.; Ou, J.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Palomba, C.; Pan, Y.; Pankow, C.; Paoletti, F.; Paoletti, R.; Papa, M. A.; Paris, H.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Pedraza, M.; Peiris, P.; Penn, S.; Perreca, A.; Phelps, M.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pinard, L.; Pindor, B.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Poeld, J.; Poggiani, R.; Poole, V.; Poux, C.; 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.; Quetschke, V.; Quintero, E.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Rácz, I.; Radkins, H.; Raffai, P.; Raja, S.; Rajalakshmi, G.; Rakhmanov, M.; Ramet, C.; Rapagnani, P.; Raymond, V.; Re, V.; Reed, C. M.; Reed, T.; Regimbau, T.; Reid, S.; Reitze, D. H.; Ricci, F.; Riesen, R.; Riles, K.; Robertson, N. A.; Robinet, F.; Rocchi, A.; Roddy, S.; Rodriguez, C.; Rodruck, M.; Roever, C.; Rolland, L.; Rollins, J. G.; Romano, J. D.; 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.; Sannibale, V.; Santiago-Prieto, I.; Saracco, E.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schuette, D.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; 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.; 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.; Soden, K.; Son, E. J.; Sorazu, B.; Souradeep, T.; Sperandio, L.; Staley, A.; Steinert, E.; Steinlechner, J.; Steinlechner, S.; Steplewski, S.; Stevens, D.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S.; Stroeer, A. S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Swinkels, B.; Szeifert, G.; Tacca, M.; Talukder, D.; Tang, L.; 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.; Vahlbruch, H.; Vajente, 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.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; Vlcek, B.; Vo, T.; Vocca, H.; Vorvick, C.; Vousden, W. D.; Vrinceanu, D.; Vyachanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Waldman, S. J.; Walker, M.; Wallace, L.; Wan, Y.; Wang, J.; Wang, M.; Wang, X.; Wanner, A.; Ward, R. L.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Wibowo, S.; Wiesner, K.; Wilkinson, C.; Williams, L.; Williams, R.; Williams, T.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yeaton-Massey, D.; Yoshida, S.; Yum, H.; Yvert, M.; Zadrożny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, F.; Zhang, L.; Zhao, C.; Zhu, H.; Zhu, X. J.; Zotov, N.; Zucker, M. E.; Zweizig, J.
2013-11-01
We present the results of a directed search for continuous gravitational waves from unknown, isolated neutron stars in the Galactic center region, performed on two years of data from LIGO’s fifth science run from two LIGO detectors. The search uses a semicoherent approach, analyzing coherently 630 segments, each spanning 11.5 hours, and then incoherently combining the results of the single segments. It covers gravitational wave frequencies in a range from 78 to 496 Hz and a frequency-dependent range of first-order spindown values down to -7.86×10-8Hz/s at the highest frequency. No gravitational waves were detected. The 90% confidence upper limits on the gravitational wave amplitude of sources at the Galactic center are ˜3.35×10-25 for frequencies near 150 Hz. These upper limits are the most constraining to date for a large-parameter-space search for continuous gravitational wave signals.
Gravitational waves from the cosmological QCD transition
NASA Astrophysics Data System (ADS)
Mourão Roque, V. R. C.; Roque, G. Lugones o.; Lugones, G.
2014-09-01
We determine the minimum fluctuations in the cosmological QCD phase transition that could be detectable by the eLISA/NGO gravitational wave observatory. To this end, we performed several hydrodynamical simulations using a state-of-the-art equation of state derived from lattice QCD simulations. Based on the fact that the viscosity per entropy density of the quark gluon plasma obtained from heavy-ion collision experiments at the RHIC and the LHC is extremely small, we considered a non-viscous fluid in our simulations. Several previous works about this transition considered a first order transition that generates turbulence which follows a Kolmogorov power law. We show that for the QCD crossover transition the turbulent spectrum must be very different because there is no viscosity and no source of continuous energy injection. As a consequence, a large amount of kinetic energy accumulates at the smallest scales. From the hydrodynamic simulations, we have obtained the spectrum of the gravitational radiation emitted by the motion of the fluid, finding that, if typical velocity and temperature fluctuations have an amplitude Δ v /c ≳ 10-2 and/or Δ T/T_c ≳ 10-3, they would be detected by eLISA/NGO at frequencies larger than ˜ 10-4 Hz.
DETECTING GRAVITATIONAL WAVE MEMORY WITH PULSAR TIMING
Cordes, J. M.; Jenet, F. A. E-mail: merlyn@phys.utb.edu
2012-06-10
We compare the detectability of gravitational bursts passing through the solar system with those passing near each millisecond pulsar in an N-pulsar timing array. The sensitivity to Earth-passing bursts can exploit the correlation expected in pulse arrival times while pulsar-passing bursts, though uncorrelated between objects, provide an N-fold increase in overall time baseline that can compensate for the lower sensitivity. Bursts with memory from mergers of supermassive black holes produce step functions in apparent spin frequency that are the easiest to detect in pulsar timing. We show that the burst rate and amplitude distribution, while strongly dependent on inadequately known cosmological evolution, may favor detection in the pulsar terms rather than the Earth timing perturbations. Any contamination of timing data by red spin noise makes burst detection more difficult because both signals grow with the length of the time data span T. Furthermore, the different bursts that could appear in one or more data sets of length T Almost-Equal-To 10 yr also affect the detectability of the gravitational wave stochastic background that, like spin noise, has a red power spectrum. A burst with memory is a worthwhile target in the timing of multiple pulsars in a globular cluster because it should produce a correlated signal with a time delay of less than about 10 years in some cases.
Using Gravitational-Wave Standard Sirens
NASA Astrophysics Data System (ADS)
Holz, Daniel E.; Hughes, Scott A.
2005-08-01
Gravitational waves (GWs) from supermassive binary black hole (BBH) in-spirals are potentially powerful standard sirens (the GW analog to standard candles; see work of B. Schutz). Because these systems are well modeled, the space-based GW observatory LISA will be able to measure the luminosity distance (but not the redshift) to some distant massive BBH systems with 1%-10% accuracy. This accuracy is largely limited by pointing error: GW sources are generally poorly localized on the sky. Localizing the binary independently (e.g., through association with an electromagnetic counterpart) greatly reduces this positional error. An electromagnetic counterpart may also allow determination of the event's redshift. In this case, BBH coalescence would constitute an extremely precise (better than 1%) standard candle visible to high redshift. In practice, gravitational lensing degrades this precision, although the candle remains precise enough to provide useful information about the distance-redshift relation. Even if very rare, these GW standard sirens would complement, and increase confidence in, other standard candles.
Black Holes, Gravitational Waves, and LISA
NASA Technical Reports Server (NTRS)
Baker, John
2009-01-01
Binary black hole mergers are central to many key science objectives of the Laser Interferometer Space Antenna (LISA). For many systems the strongest part of the signal is only understood by numerical simulations. Gravitational wave emissions are understood by simulations of vacuum General Relativity (GR). I discuss numerical simulation results from the perspective of LISA's needs, with indications of work that remains to be done. Some exciting scientific opportunities associated with LISA observations would be greatly enhanced if prompt electromagnetic signature could be associated. I discuss simulations to explore this possibility. Numerical simulations are important now for clarifying LISA's science potential and planning the mission. We also consider how numerical simulations might be applied at the time of LISA's operation.
On a nonlinear gravitational wave. Geodesics
NASA Astrophysics Data System (ADS)
Culetu, Hristu
2016-12-01
An exact, plane-wave solution of the gravitational field equations is investigated. The source stress tensor is represented by an anisotropic null fluid with energy flux to which the energy density ρ and all pressures are finite throughout the spacetime. They depend on a constant length (taken of the order of the Planck length) and acquire Planck values close to the null surface t-z=0, the z-axis being the direction of propagation. However, ρ and p become positive when a cross-polarization term is introduced in the line element. The timelike geodesics of a test particle are contained in a plane whose normal has constant direction and the null trajectories are comoving with a plane of fixed direction.
Constraining the Braneworld with Gravitational Wave Observations
NASA Technical Reports Server (NTRS)
McWilliams, Sean T.
2011-01-01
Some braneworld models may have observable consequences that, if detected, would validate a requisite element of string theory. In the infinite Randall-Sundrum model (RS2), the AdS radius of curvature, L, of the extra dimension supports a single bound state of the massless graviton on the brane, thereby reproducing Newtonian gravity in the weak-field limit. However, using the AdS/CFT correspondence, it has been suggested that one possible consequence of RS2 is an enormous increase in Hawking radiation emitted by black holes. We utilize this possibility to derive two novel methods for constraining L via gravitational wave measurements. We show that the EMRI event rate detected by LISA can constrain L at the approximately 1 micron level for optimal cases, while the observation of a single galactic black hole binary with LISA results in an optimal constraint of L less than or equal to 5 microns.
The Mario Schenberg Gravitational Wave Antenna
NASA Astrophysics Data System (ADS)
Oliveira, Nei F.; Aguiar, Odylio D.
2016-10-01
This article is an account of the work done in the Mario Schenberg gravitational wave antenna up to date, focusing mainly in the participation of the Laboratório de Estado Sólido e Baixas Temperaturas (LESBT) do Instituto de Física da Universidade de S. Paulo. The text starts with an introduction describing the problem, the Brazilian project, and the participant institutions. This is followed by a description of the construction of the infrastructure, initial tests, and final basic assembly at the LESBT. Results are presented for the thermal and mechanical behaviors of the cryogenic system and for the development of active transducers in its various stages, culminating with the last version in which the project sensitivity of ˜4 × 10-20 Hz-1/2 was attained.
Demorest, P. B.; Ransom, S.; Ferdman, R. D.; Kaspi, V. M.; Gonzalez, M. E.; Stairs, I. H.; Nice, D.; Arzoumanian, Z.; Brazier, A.; Cordes, J. M.; Burke-Spolaor, S.; Lazio, J.; Chamberlin, S. J.; Ellis, J.; Giampanis, S.; Finn, L. S.; Freire, P.; Jenet, F.; Lommen, A. N.; McLaughlin, M.; and others
2013-01-10
We present an analysis of high-precision pulsar timing data taken as part of the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) project. We have observed 17 pulsars for a span of roughly five years using the Green Bank and Arecibo radio telescopes. We analyze these data using standard pulsar timing models, with the addition of time-variable dispersion measure and frequency-variable pulse shape terms. Sub-microsecond timing residuals are obtained in nearly all cases, and the best rms timing residuals in this set are {approx}30-50 ns. We present methods for analyzing post-fit timing residuals for the presence of a gravitational wave signal with a specified spectral shape. These optimally take into account the timing fluctuation power removed by the model fit, and can be applied to either data from a single pulsar, or to a set of pulsars to detect a correlated signal. We apply these methods to our data set to set an upper limit on the strength of the nHz-frequency stochastic supermassive black hole gravitational wave background of h{sub c} (1 yr{sup -1}) < 7 Multiplication-Sign 10{sup -15} (95%). This result is dominated by the timing of the two best pulsars in the set, PSRs J1713+0747 and J1909-3744.
Black-Hole Binaries, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Kelly, Bernard J.; Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.
2010-01-01
Understanding the predictions of general relativity for the dynamical interactions of two black holes has been a long-standing unsolved problem in theoretical physics. Black-hole mergers are monumental astrophysical events ' releasing tremendous amounts of energy in the form of gravitational radiation ' and are key sources for both ground- and spacebased gravitational wave detectors. The black-hole merger dynamics and the resulting gravitational waveforms can only he calculated through numerical simulations of Einstein's equations of general relativity. For many years, numerical relativists attempting to model these mergers encountered a host of problems, causing their codes to crash after just a fraction of a binary orbit cnuld be simulated. Recently ' however, a series of dramatic advances in numerical relativity has ' for the first time, allowed stable / robust black hole merger simulations. We chronicle this remarkable progress in the rapidly maturing field of numerical relativity, and the new understanding of black-hole binary dynamics that is emerging. We also discuss important applications of these fundamental physics results to astrophysics, to gravitationalwave astronomy, and in other areas.
LISA Pathfinder: First steps to observing gravitational waves from space
NASA Astrophysics Data System (ADS)
McNamara, Paul; LISA Pathfinder Collaboration
2017-01-01
With the first direct detection of gravitational waves a little over a year ago, the gravitational window to the Universe has been opened. The gravitational wave spectrum spans many orders of magnitude in frequency, with several of the most interesting astronomical sources emitting gravitational waves at frequencies only observable from space The European Space Agency (ESA) has been active in the field of space-borne gravitational wave detection for many years, and in 2013 selected the Gravitational Universe as the science theme for the third large class mission in the Cosmic Vision science programme. In addition, ESA took the step of developing the LISA Pathfinder mission to demonstrate the critical technologies required for a future mission. The goal of the LISA Pathfinder mission is to place a test body in free fall such that any external forces (acceleration) are reduced to levels lower than those expected from the passage of a gravitational wave LISA Pathfinder was launched on the 3rd December 2015 from the European Spaceport in Kourou, French Guiana. After a series of 6 apogee raising manoeuvres, the satellite left earth orbit, and travelled to its final science orbit around the first Sun-Earth Lagrange point (L1). Following a relatively short commissioning phase, science operations began on 1st March 2016. In the following 3 months over 100 experiments and over 1500hours of noise measurements have been performed, demonstrating that the observation of gravitational waves from space can be realised.
Accumulative coupling between magnetized tenuous plasma and gravitational waves
NASA Astrophysics Data System (ADS)
Zhang, Fan
2017-01-01
This talk presents solutions to the plasma waves induced by a plane gravitational wave (GW) train travelling through a region of strongly magnetized plasma. The computations constitute a very preliminary feasibility study for a possible ultra-high frequency gravitational wave detector, meant to take advantage of the observation that the plasma current is proportional to the GW amplitude, and not its square. This work is supported in part by NSFC Grant Number 11503003.
Problems related to gravitational waves from binary black holes
NASA Astrophysics Data System (ADS)
Tsokaros, Antonios A.
With three gravitational wave observatories LIGO, GEO, and TAMA in operation the dawn of gravitational wave astronomy is nearly a reality. In the coming decade these earth-based observatories together with the expected space-based, LISA will play a major role in advancing our knowledge of our cosmic habitat. The first targets for gravitational wave detectors like LIGO are the waves emitted by pairs of compact objects (neutron stars and black holes) that orbit each other. Developing an accurate numerical model for these binary coalescence is crucial to maximize the number of events that the gravitational-wave detectors will see and to extract from observed events the physics of the coalescing objects. The first step in studying the dynamics of this sort is to obtain astrophysically realistic initial data sets that represent such binaries. Although for the binary neutron stars that is already achieved, things have proven to be more difficult for the binary black hole case. In this study we analyze Einstein's equations in the presence of a helical killing vector and try to obtain initial data sets by solving five, instead of four, semi-elliptic equations. For the background metric we assumed a linear superposition of two Kerr metrics written in the Kerr-Schild form. A new computational technique with overlapping spherical domains for the solution of such semi-elliptic equations for two black holes of different masses was developed. In addition, motivated by the necessity of predicting realistic waveforms, we investigate the self-force experienced by a static non-minimally-coupled scalar charge outside a Schwarzschild black hole. We find that the finite part of this self-force is zero. To arrive at this result, we employ a Gedankenexperiment where the force is determined from the work required to slowly raise or lower the particle an infinitesimal distance. Our no-self-force result is in disagreement with a previous result of Zel'nikov and Frolov, who have suggested
Speed of Gravitational Waves from Strongly Lensed Gravitational Waves and Electromagnetic Signals.
Fan, Xi-Long; Liao, Kai; Biesiada, Marek; Piórkowska-Kurpas, Aleksandra; Zhu, Zong-Hong
2017-03-03
We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival times of GWs and their EM counterparts and by comparing the time delays between images seen in GWs and their EM counterparts. The lensed GW-EM event is perhaps the best way to identify an EM counterpart. Conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. Its differential setting (i.e., measuring the difference between time delays in GW and EM domains) makes it robust against lens modeling details (photons and GWs travel in the same lensing potential) and against internal time delays between GW and EM emission acts. It requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. We expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed GW events would be observed each year. The power of this method is mainly limited by the timing accuracy of the EM counterpart, which for kilonovae is around 10^{4} s. This uncertainty can be suppressed by a factor of ∼10^{10}, if strongly lensed transients of much shorter duration associated with the GW event can be identified. Candidates for such short transients include short γ-ray bursts and fast radio bursts.
Speed of Gravitational Waves from Strongly Lensed Gravitational Waves and Electromagnetic Signals
NASA Astrophysics Data System (ADS)
Fan, Xi-Long; Liao, Kai; Biesiada, Marek; Piórkowska-Kurpas, Aleksandra; Zhu, Zong-Hong
2017-03-01
We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival times of GWs and their EM counterparts and by comparing the time delays between images seen in GWs and their EM counterparts. The lensed GW-EM event is perhaps the best way to identify an EM counterpart. Conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. Its differential setting (i.e., measuring the difference between time delays in GW and EM domains) makes it robust against lens modeling details (photons and GWs travel in the same lensing potential) and against internal time delays between GW and EM emission acts. It requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. We expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed GW events would be observed each year. The power of this method is mainly limited by the timing accuracy of the EM counterpart, which for kilonovae is around 1 04 s . This uncertainty can be suppressed by a factor of ˜1 010, if strongly lensed transients of much shorter duration associated with the GW event can be identified. Candidates for such short transients include short γ -ray bursts and fast radio bursts.
Earth-orbiting resonant-mass gravitational wave detectors
NASA Technical Reports Server (NTRS)
Paik, Ho Jung
1989-01-01
Earth-based gravitational wave detectors suffer from the need to support the large antenna masses against the earth's gravity without transmitting a significant amount of seismic noise. Passive vibration isolation is difficult to achieve below 1 Hz on the earth. Vibration-free space environment thus gives an opportunity to extend the frequency window of gravitational wave detection to ultralow frequencies. The weightless condition of a space laboratory also enables construction of a highly symmetric multimode antenna which is capable of resolving the direction of the source and the polarization of the incoming wave without resorting to multiantenna coincidence. Two types of earth-orbiting resonant-mass gravitational wave detectors are considered. One is a skyhook gravitational wave detector, proposed by Braginsky and Thorne (1985). The other is a spherical detector, proposed by Forward (1971) and analyzed by Wagoner and Paik (1976).
Squeezed light for advanced gravitational wave detectors and beyond.
Oelker, E; Barsotti, L; Dwyer, S; Sigg, D; Mavalvala, N
2014-08-25
Recent experiments have demonstrated that squeezed vacuum states can be injected into gravitational wave detectors to improve their sensitivity at detection frequencies where they are quantum noise limited. Squeezed states could be employed in the next generation of more sensitive advanced detectors currently under construction, such as Advanced LIGO, to further push the limits of the observable gravitational wave Universe. To maximize the benefit from squeezing, environmentally induced disturbances such as back scattering and angular jitter need to be mitigated. We discuss the limitations of current squeezed vacuum sources in relation to the requirements imposed by future gravitational wave detectors, and show a design for squeezed light injection which overcomes these limitations.
Twin mirrors for laser interferometric gravitational-wave detectors.
Sassolas, Benoît; Benoît, Quentin; Flaminio, Raffaele; Forest, Danièle; Franc, Janyce; Galimberti, Massimo; Lacoudre, Aline; Michel, Christophe; Montorio, Jean-Luc; Morgado, Nazario; Pinard, Laurent
2011-05-01
Gravitational-wave detectors such as Virgo and the laser interferometric gravitational-wave observatory (LIGO) use a long-baseline Michelson interferometer with Fabry-Perot cavities in the arms to search for gravitational waves. The symmetry between the two Fabry-Perot cavities is crucial to reduce the interferometer's sensitivity to the laser amplitude and frequency noise. To this purpose, the transmittance of the mirrors in both cavities should be as close as possible. This paper describes the realization and the characterization of the first twin large low-loss mirrors with transmissions differing by less than 0.01%.
Gravitational waves from Affleck-Dine condensate fragmentation
Zhou, Shuang-Yong
2015-06-01
We compute the stochastic gravitational wave production from Affleck-Dine condensate fragmentation in the early universe, focusing on an effective potential with a logarithmic mass correction that typically arises in gravity mediated supersymmetry breaking scenarios. We find that a significant gravitational wave background can be generated when Q-balls are being formed out of the condensate fragmentation. This gravitational wave background has a distinct multi-peak power spectrum where the trough is closely linked to the supersymmetry breaking scale and whose frequencies are peaked around kHz for TeV supersymmetry breaking.
Numerical Relativity, Black Hole Mergers, and Gravitational Waves: Part III
NASA Technical Reports Server (NTRS)
Centrella, Joan
2012-01-01
This series of 3 lectures will present recent developments in numerical relativity, and their applications to simulating black hole mergers and computing the resulting gravitational waveforms. In this third and final lecture, we present applications of the results of numerical relativity simulations to gravitational wave detection and astrophysics.
Numerical Relativity, Black Hole Mergers, and Gravitational Waves: Part I
NASA Technical Reports Server (NTRS)
Centrella, Joan
2012-01-01
This series of 3 lectures will present recent developments in numerical relativity, and their applications to simulating black hole mergers and computing the resulting gravitational waveforms. In this first lecture, we introduce the basic ideas of numerical relativity, highlighting the challenges that arise in simulating gravitational wave sources on a computer.
Neutrinos from supernovae as a trigger for gravitational wave search.
Pagliaroli, G; Vissani, F; Coccia, E; Fulgione, W
2009-07-17
Exploiting an improved analysis of the nue signal from the explosion of a galactic core collapse supernova, we show that it is possible to identify within about 10 ms the time of the bounce, which is strongly correlated to the time of the maximum amplitude of the gravitational signal. This allows us to precisely identify the gravitational wave burst timing.
Calibrating Atmospheric Delay for the Cassini Gravitational Wave Experiment
NASA Technical Reports Server (NTRS)
Resch, G. M.; Keihm, S. J.; Naudet, C. J.; Riley, A. L.; Tanner, A. B.; Teitelbaum, L. P.; Linfield, R. P.
2000-01-01
The Cassini spacecraft together with one of the stations of the Deep Space Network (DSN) have been instrumented to carry out extremely precise Doppler tracking that will be used to search for the direct evidence of Gravitational radiation passing through our solar system. The two-way communications link between the ground antenna and the spacecraft constitute an "antenna" for gravitational waves that would perturb the phase of the RF signal in the link. The experiments will be carried out during the long cruise phase of the spacecraft on its journey to Saturn and will be sensitive to gravitational wave perturbations larger than the noise level fluctuations of 3 x 10(exp -15) as measured in the Allan Standard Deviation domain. The use of simultaneous, coherent X- and Ka-Band up and down signals will reduce the errors associated with charged particle fluctuations in the interplanetary medium and Earth's ionosphere to a negligible level. The primary fluctuations in the phase of the signals both to and from the spacecraft are expected to be caused by fluctuations in water vapor in the Earth's atmosphere We have designed and are testing a new atmospheric calibration system (with duplicate components) to sense line-of-sight water vapor and its physical temperature with a goal of calibrating 95% or more of tropospheric path delay fluctuations during the Cassini Gravitational Wave Experiment (GWE). The critical component of the calibration system consists of a newly designed water vapor radiometer having a I degree sensing beamwidth and 0.01 K brightness temperature stability over hour time scales. Auxiliary instrumentation includes a microwave temperature profiler to retrieve the vertical distribution of the vapor physical temperature, and surface meteorology. A detailed error budget has been developed to account for all of the possible sources of error during calibration of the GWE and will be discussed. Two identical calibration systems have been constructed in order to
Gravitational wave background from reheating after hybrid inflation
Garcia-Bellido, Juan; Figueroa, Daniel G.; Sastre, Alfonso
2008-02-15
The reheating of the Universe after hybrid inflation proceeds through the nucleation and subsequent collision of large concentrations of energy density in the form of bubblelike structures moving at relativistic speeds. This generates a significant fraction of energy in the form of a stochastic background of gravitational waves, whose time evolution is determined by the successive stages of reheating: First, tachyonic preheating makes the amplitude of gravity waves grow exponentially fast. Second, bubble collisions add a new burst of gravitational radiation. Third, turbulent motions finally sets the end of gravitational waves production. From then on, these waves propagate unimpeded to us. We find that the fraction of energy density today in these primordial gravitational waves could be significant for grand unified theory (GUT)-scale models of inflation, although well beyond the frequency range sensitivity of gravitational wave observatories like LIGO, LISA, or BBO. However, low-scale models could still produce a detectable signal at frequencies accessible to BBO or DECIGO. For comparison, we have also computed the analogous gravitational wave background from some chaotic inflation models and obtained results similar to those found by other groups. The discovery of such a background would open a new observational window into the very early universe, where the details of the process of reheating, i.e. the big bang, could be explored. Moreover, it could also serve in the future as a new experimental tool for testing the inflationary paradigm.
Search for Gravitational Waves Associated with the August 2006 Timing Glitch of the Vela Pulsar
NASA Technical Reports Server (NTRS)
Camp, J. B.; Cannizzo, J.; Stroeer, A.
2011-01-01
The physical mechanisms responsible for pulsar timing glitches are thought to excite quasinormal mode oscillations in their parent neutron star that couple to gravitational-wave emission, In August 2006, a timing glitch was observed in the radio emission of PSR B0833-45, the Vela pulsar. At the time of the glitch, the two colocated Hanford gravitational-wave detectors of the Laser Interferometer Gravitational-wave observatory (LIGO) were operational and taking data as part of the fifth LIGO science run (S5). We present the first direct search for the gravitational-wave emission associated with oscillations of the fundamental quadrupole mode excited by a pulsar timing glitch. No gravitational-wave detection candidate was found. We place Bayesian 90% confidence upper limits of 6,3 x 10(exp -21) to 1.4 x 10(exp -20) on the peak: intrinsic strain amplitude of gravitational-wave ring-down signals, depending on which spherical harmonic mode is excited. The corresponding range of energy upper limits is 5.0 x 10(exp 44) to 1.3 x 10(exp 45) erg.
NASA's Gravitational - Wave Mission Concept Study
NASA Technical Reports Server (NTRS)
Stebbins, Robin; Jennrich, Oliver; McNamara, Paul
2012-01-01
With the conclusion of the NASA/ESA partnership on the Laser Interferometer Space Antenna (LISA) Project, NASA initiated a study to explore mission concepts that will accomplish some or all of the LISA science objectives at lower cost. The Gravitational-Wave Mission Concept Study consisted of a public Request for Information (RFI), a Core Team of NASA engineers and scientists, a Community Science Team, a Science Task Force, and an open workshop. The RFI yielded were 12 mission concepts, 3 instrument concepts and 2 technologies. The responses ranged from concepts that eliminated the drag-free test mass of LISA to concepts that replace the test mass with an atom interferometer. The Core Team reviewed the noise budgets and sensitivity curves, the payload and spacecraft designs and requirements, orbits and trajectories and technical readiness and risk. The Science Task Force assessed the science performance by calculating the horizons. the detection rates and the accuracy of astrophysical parameter estimation for massive black hole mergers, stellar-mass compact objects inspiraling into central engines. and close compact binary systems. Three mission concepts have been studied by Team-X, JPL's concurrent design facility. to define a conceptual design evaluate kt,y performance parameters. assess risk and estimate cost and schedule. The Study results are summarized.
Studies for Improved Gravitational Wave Sensitivity
NASA Technical Reports Server (NTRS)
Bender, Peter L.
2003-01-01
The main purpose of this study was to investigate the possible accuracy of the Laser Interferometer Space Antenna (LISA) for studying gravitational waves at frequencies below the usually quoted frequency range of 100 microHz to 1 Hz. The extended frequency range of most interest is from 3 to 100 microHz. During this work, a new source of spurious accelerations of the test masses for LISA that had been overlooked previously was identified. It is one of the main noise contributors at 100 microHz, and rises as the inverse of the frequency to become probably the largest error source at 3 microHz. The new error source is fluctuations in the charge on the test mass due to cosmic ray charging interacting with the electric fields inside the housing that carries the capacitive electrodes for sensing relative motion of the test mass with respect to the housing. Even for zero charge on the test mass, there will be electrical fields acting on each face due to work function differences between the capacitive electrodes and the test mass.
Gravitational Wave Emulation Using Gaussian Process Regression
NASA Astrophysics Data System (ADS)
Doctor, Zoheyr; Farr, Ben; Holz, Daniel
2017-01-01
Parameter estimation (PE) for gravitational wave signals from compact binary coalescences (CBCs) requires reliable template waveforms which span the parameter space. Waveforms from numerical relativity are accurate but computationally expensive, so approximate templates are typically used for PE. These `approximants', while quick to compute, can introduce systematic errors and bias PE results. We describe a machine learning method for generating CBC waveforms and uncertainties using existing accurate waveforms as a training set. Coefficients of a reduced order waveform model are computed and each treated as arising from a Gaussian process. These coefficients and their uncertainties are then interpolated using Gaussian process regression (GPR). As a proof of concept, we construct a training set of approximant waveforms (rather than NR waveforms) in the two-dimensional space of chirp mass and mass ratio and interpolate new waveforms with GPR. We demonstrate that the mismatch between interpolated waveforms and approximants is below the 1% level for an appropriate choice of training set and GPR kernel hyperparameters.
Theoretical implications of detecting gravitational waves
Geshnizjani, Ghazal; Kinney, William H. E-mail: whkinney@buffalo.edu
2015-08-01
This paper is the third in a series of theorems which state how cosmological observations can provide evidence for an early phase of acceleration in the universe. It was demonstrated in [1,2], that the observed power spectrum for scalar perturbations forces all possible alternative theories of inflation to theories other than General Relativity. It was shown that generically, without a phase of accelerated expansion, these alternatives have to break at least one of the following tenets of classical general relativity: the Null Energy Condition (NEC), subluminal signal propagation, or sub-Planckian energy densities. In this paper we prove how detection of primordial gravitational waves at large scales can provide independent evidence to support a phase of accelerated expansion. This proof does not rely on the spectral index for tensor modes but relies on validity of quantum field theory in curved space time and tensor modes being sourced from adiabatic vacuum fluctuations. Our approach, like in the case of scalars, is proof by contradiction: we investigate the possibility of a detectable tensor signal sourced by vacuum fluctuations in a non-accelerating, sub-Planckian universe using cosmological perturbation theory and derive contradictory limits on cosmological dynamics. The contradiction implies that one or more of our axioms for early universe must have been broken. The bound from tensor perturbations is not only independent of, but also stronger than the one obtained from scalar power spectrum.
From photons to gravitational waves: pulsars in the era of multimessenger astronomy
NASA Astrophysics Data System (ADS)
Razzano, Massimiliano
2015-08-01
Multiwavelength astronomy has provided the most complete picture of the Universe so far. In the coming years the second-generation interferometers like Advanced LIGO and Advanced Virgo will reach sensitivities good enough to detect the first gravitational wave signals, opening a new window on the cosmos. In this new era of multimessenger astronomy, pulsars are very promising candidates to be studied using electromagnetic radiation and gravitational waves. In fact, being the endpoints of the evolution of massive stars, they are great tools to understand stellar structure and evolution, as well as the population of the Galaxy. Moreover, they are excellent natural laboratories to probe the laws of Physics under extreme conditions of gravity and elecromagnetic fields. I will review the multimessenger opportunities for the electromagnetic and gravitational observations of pulsars, highlighting their potential as continuous gravitational waves emitters.
Black Hole Kicks as New Gravitational Wave Observables.
Gerosa, Davide; Moore, Christopher J
2016-07-01
Generic black hole binaries radiate gravitational waves anisotropically, imparting a recoil, or kick, velocity to the merger remnant. If a component of the kick along the line of sight is present, gravitational waves emitted during the final orbits and merger will be gradually Doppler shifted as the kick builds up. We develop a simple prescription to capture this effect in existing waveform models, showing that future gravitational wave experiments will be able to perform direct measurements, not only of the black hole kick velocity, but also of its accumulation profile. In particular, the eLISA space mission will measure supermassive black hole kick velocities as low as ∼500 km s^{-1}, which are expected to be a common outcome of black hole binary coalescence following galaxy mergers. Black hole kicks thus constitute a promising new observable in the growing field of gravitational wave astronomy.
Visualization of Merging Black Holes and Gravitational Waves
This visualization shows gravitational waves emitted by two black holes of nearly equal mass as they spiral together and merge. Orange ripples represent distortions of space-time caused by the rapi...
Two Timescale Approximation Applied to Gravitational Waves from Eccentric EMRIs
NASA Astrophysics Data System (ADS)
Moxon, Jordan; Flanagan, Eanna; Hinderer, Tanja; Pound, Adam
2016-03-01
Gravitational-wave driven inspirals of compact objects into massive black holes (Extreme Mass Ratio Inspirals - EMRIs) form an interesting, long-lived signal for future space-based gravitational wave detectors. Accurate signal predictions will be necessary to take full advantage of matched filtering techniques, motivating the development of a calculational technique for deriving the gravitational wave signal to good approximation throughout the inspiral. We report on recent work on developing the two-timescale technique with the goal of predicting waveforms from eccentric equatorial systems to subleading (post-adiabatic) order in the phase, building on recent work by Pound in the scalar case. The computation requires us to understand the dissipative component of the second-order self force. It also demands careful consideration of how the two timescale (near-zone) approximation should match with the post-Minkowski approximation of the gravitational waves at great distances.
Multiple Signal Classification for Gravitational Wave Burst Search
NASA Astrophysics Data System (ADS)
Cao, Junwei; He, Zhengqi
2013-01-01
This work is mainly focused on the application of the multiple signal classification (MUSIC) algorithm for gravitational wave burst search. This algorithm extracts important gravitational wave characteristics from signals coming from detectors with arbitrary position, orientation and noise covariance. In this paper, the MUSIC algorithm is described in detail along with the necessary adjustments required for gravitational wave burst search. The algorithm's performance is measured using simulated signals and noise. MUSIC is compared with the Q-transform for signal triggering and with Bayesian analysis for direction of arrival (DOA) estimation, using the Ω-pipeline. Experimental results show that MUSIC has a lower resolution but is faster. MUSIC is a promising tool for real-time gravitational wave search for multi-messenger astronomy.
The Science of Gravitational Waves with Space Observatories
NASA Technical Reports Server (NTRS)
Thorpe, James Ira
2013-01-01
After decades of effort, direct detection of gravitational waves from astrophysical sources is on the horizon. Aside from teaching us about gravity itself, gravitational waves hold immense promise as a tool for general astrophysics. In this talk I will provide an overview of the science enabled by a space-based gravitational wave observatory sensitive in the milli-Hertz frequency band including the nature and evolution of massive black holes and their host galaxies, the demographics of stellar remnant compact objects in the Milky Way, and the behavior of gravity in the strong-field regime. I will also summarize the current status of efforts in the US and Europe to implement a space-based gravitational wave observatory.
Gravitational-Wave Detectors: First, Second, and Third Generation
Mandic, Vuk
2011-11-02
Gravitational waves are predicted by the general theory of relativity to be produced by accelerating mass systems with quadrupole (or higher) moment. The amplitude of gravitational waves is expected to be very small, so the best chance of their direct detection lies with some of the most energetic events in the universe, such as mergers of two neutron stars or black holes, supernova explosions, or the Big Bang itself. Over the past decade several detectors have been built to search for such gravitational-wave sources. This talk will review the current status of these detectors, as well as some of their most recent results, and will cover plans and expectations for the future generations of gravitational wave detectors.
Hearing the echoes of electroweak baryogenesis with gravitational wave detectors
NASA Astrophysics Data System (ADS)
Huang, Fa Peng; Wan, Youping; Wang, Dong-Gang; Cai, Yi-Fu; Zhang, Xinmin
2016-08-01
We report on the first joint analysis of observational signatures from the electroweak baryogenesis in both gravitational wave (GW) detectors and particle colliders. With an effective extension of the Higgs sector in terms of the dimension-six operators, we derive a strong first-order phase transition associated with a sizable CP violation to realize a successful electroweak baryogenesis. We calculate the GW spectrum resulting from the bubble nucleation, plasma transportation, and magnetohydrodynamic turbulence of this process that occurred after the big bang and find that it yields GW signals testable with the Evolved Laser Interferometer Space Antenna, Deci-hertz Interferometer Gravitational Wave Observatory, and Big Bang Observer. We further identify collider signals from the same mechanism that are observable at the planning Circular Electron Positron Collider. Our analysis bridges astrophysics and cosmology with particle physics by providing significant motivation for searches for GW events peaking at the (1 0-4,1 ) Hz range, which are associated with signals at colliders, and highlights the possibility of an interdisciplinary observational window into baryogenesis. The technique applied in analyzing early Universe phase transitions may enlighten the study of phase transitions in applied science.
Resource Letter GrW-1: Gravitational Waves
NASA Technical Reports Server (NTRS)
White, Nicholas E. (Technical Monitor); Centrella, Joan M.
2003-01-01
The phenomenon of gravitational radiation was one of the first predictions of Einstein's general theory of relativity. Progress in understanding this radiation theoretically was slow at first, owing to the difficulty of the nonlinear field equations and the subtleties of their physical effects. The experimental side of this subject also has taken a long time to develop, with efforts at detection severely challenged by the extreme weakness of the waves impinging on the Earth. However, as the 21st century begins, observations of the gravitational waves from astrophysical sources such as black holes, neutron stars, and stellar collapse are expected to open a new window on the universe. Vigorous experimental programs centered on ground-based detectors are being carried out worldwide, and a space-based detector is in the planning stages. On the theoretical side, much effort is being expended to produce robust models of the astrophysical sources and accurate calculations of the waveforms they produce. In this Resource Letter, a set of basic references will be presented first, to provide a general introduction to and overview of the literature in this field. The focus then will shift to highlighting key resources in more specialized areas at the forefront of current research.
Electromagnetic waves and Stokes parameters in the wake of a gravitational wave
NASA Astrophysics Data System (ADS)
Hacyan, Shahen
2012-11-01
A theoretical description of electromagnetic waves in the background of a (weak) gravitational wave is presented. Explicit expressions are obtained for the Stokes parameters during the passage of a plane-fronted gravitational wave described by the Ehlers-Kundt metric. In particular, it is shown that the axis of the polarization ellipse oscillates, its ellipticity remaining constant.
Perturbative and gauge invariant treatment of gravitational wave memory
NASA Astrophysics Data System (ADS)
Bieri, Lydia; Garfinkle, David
2014-04-01
We present a perturbative treatment of gravitational wave memory. The coordinate invariance of Einstein's equations leads to a type of gauge invariance in perturbation theory. As with any gauge invariant theory, results are more clear when expressed in terms of manifestly gauge invariant quantities. Therefore we derive all our results from the perturbed Weyl tensor rather than the perturbed metric. We derive gravitational wave memory for the Einstein equations coupled to a general energy-momentum tensor that reaches null infinity.
Exploring the sensitivity of next generation gravitational wave detectors
NASA Astrophysics Data System (ADS)
Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Ackley, K.; Adams, C.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Allen, B.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arun, K. G.; Ashton, G.; Ast, M.; Aston, S. M.; Aufmuth, P.; Aulbert, C.; Babak, S.; Baker, P. T.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barr, B.; Barsotti, L.; Bartlett, J.; Bartos, I.; Bassiri, R.; Batch, J. C.; Baune, C.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Biwer, C.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bock, O.; Bogan, C.; Bohe, A.; Bond, C.; Bork, R.; Bose, S.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Brinkmann, M.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Buonanno, A.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Caride, S.; Caudill, S.; Cavaglià, M.; Cepeda, C. B.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, C.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Collette, C. G.; Cominsky, L.; Constancio, M., Jr.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Dal Canton, T.; Danilishin, S. L.; Danzmann, K.; Darman, N. S.; Dasgupta, A.; Da Silva Costa, C. F.; Dave, I.; Davies, G. S.; Daw, E. J.; De, S.; DeBra, D.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Díaz, M. C.; Di Palma, I.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Fenyvesi, E.; Ferreira, E. C.; Fisher, R. P.; Fletcher, M.; Frei, Z.; Freise, A.; Frey, R.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gaonkar, S. G.; Gaur, G.; Gehrels, N.; Geng, P.; George, J.; Gergely, L.; Ghosh, Abhirup; Ghosh, Archisman; Giaime, J. A.; Giardina, K. D.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Graef, C.; Graff, P. B.; Grant, A.; Gras, S.; Gray, C.; Green, A. C.; Grote, H.; Grunewald, S.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heintze, M. C.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isi, M.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jang, H.; Jani, K.; Jawahar, S.; Jian, L.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalili, F. Y.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chi-Woong; Kim, Chunglee; Kim, J.; Kim, K.; Kim, N.; Kim, W.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kozak, D. B.; Kringel, V.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leong, J. R.; Levin, Y.; Lewis, J. B.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lormand, M.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martin, I. W.; Martynov, D. V.; Mason, K.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Meshkov, S.; Messenger, C.; Messick, C.; Meyers, P. M.; Miao, H.; Middleton, H.; Mikhailov, E. E.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Mohapatra, S. R. P.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nayak, R. K.; Nedkova, K.; Nelson, T. J. N.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nitz, A.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O’Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O’Reilly, B.; O’Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Perri, L. M.; Phelps, M.; Pierro, V.; Pinto, I. M.; Pitkin, M.; Poe, M.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prokhorov, L.; Puncken, O.; Pürrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rakhmanov, M.; Raymond, V.; Read, J.; Reed, C. M.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Rollins, J. G.; Roma, V. J.; Romanov, G.; Romie, J. H.; Rowan, S.; Rüdiger, A.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O. E. S.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sergeev, A.; Shaddock, D. A.; Shaffer, T.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Szczepańczyk, M. J.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tomlinson, C.; Tornasi, Z.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Traylor, G.; Trifirò, D.; Tse, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vander-Hyde, D. C.; van Veggel, A. A.; Vass, S.; Vaulin, R.; Vecchio, A.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Vinciguerra, S.; Vine, D. J.; Vitale, S.; Vo, T.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Weaver, B.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yu, H.; Zanolin, M.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; (LIGO Scientific Collaboration; Harms, J.
2017-02-01
The second-generation of gravitational-wave detectors are just starting operation, and have already yielding their first detections. Research is now concentrated on how to maximize the scientific potential of gravitational-wave astronomy. To support this effort, we present here design targets for a new generation of detectors, which will be capable of observing compact binary sources with high signal-to-noise ratio throughout the Universe.
Numerical Relativity for Space-Based Gravitational Wave Astronomy
NASA Technical Reports Server (NTRS)
Baker, John G.
2011-01-01
In the next decade, gravitational wave instruments in space may provide high-precision measurements of gravitational-wave signals from strong sources, such as black holes. Currently variations on the original Laser Interferometer Space Antenna mission concepts are under study in the hope of reducing costs. Even the observations of a reduced instrument may place strong demands on numerical relativity capabilities. Possible advances in the coming years may fuel a new generation of codes ready to confront these challenges.
Effect of Extra Dimensions on Gravitational Waves from Cosmic Strings
O'Callaghan, Eimear; Chadburn, Sarah; Geshnizjani, Ghazal; Gregory, Ruth; Zavala, Ivonne
2010-08-20
We show how the motion of cosmic superstrings in extra dimensions can modify the gravitational wave signal from cusps. Additional dimensions both round off cusps, as well as reducing the probability of their formation, and thus give a significant dimension dependent damping of the gravitational waves. We look at the implication of this effect for LIGO and LISA, as well as commenting on more general frequency bands.
Gravitational waves from surface inhomogeneities of neutron stars
NASA Astrophysics Data System (ADS)
Konar, Sushan; Mukherjee, Dipanjan; Bhattacharya, Dipankar; Sarkar, Prakash
2016-11-01
Surface asymmetries of accreting neutron stars are investigated for their mass quadrupole moment content. Though the amplitude of the gravitational waves from such asymmetries seems to be beyond the limit of detectability of the present generation of detectors, it appears that rapidly rotating neutron stars with strong magnetic fields residing in high-mass x-ray binaries would be worth considering for a targeted search for continuous gravitational waves with the next generation of instruments.
Exploring the cosmos with gravitational-waves
NASA Astrophysics Data System (ADS)
Taylor, Stephen R.; Gair, Jonathan R.; Mandel, Ilya; Lentati, Lindley; Ellis, Justin
2015-01-01
Gravitational-wave (GW) astronomy will open up a new frontier in astrophysical studies of neutron stars (NSs) and black-holes (BHs). Near-future detections will shed light on the coalescence rate of compact-object binaries, present an independent means of constraining cosmological parameters, and offer a host of other exciting opportunities. My doctoral research has followed two threads, linked by the common goal of mining rich information from near-future GW observations. In the first thread of my dissertation, I developed a technique to probe cosmological parameters with GWs in the absence of any electromagnetic counterparts. This exploits the potential for a network of GW interferometers to extract the distance of each system from the measured gravitational waveform. I use the observed intrinsic narrowness of the NS-NS mass-distribution, along with GW-measured redshifted-masses, to deduce candidate redshift distributions for each system, thereby allowing a probe of the distance-redshift relation. I find that an advanced LIGO-Virgo network can place independent, complementary constraints on the Hubble constant, whilst a third-generation network will be capable of probing the dark energy equation-of-state and the star-formation rate of the NS-NS progenitor population. In the second thread, I studied the potential for high-precision timing of millisecond pulsars to infer the perturbing influence of passing GWs. I developed a robust data-analysis pipeline to constrain the levels of anisotropy in a stochastic nanoHertz GW background using an ensemble of these pulsars. This technique cross-correlates pulse time-of-arrival deviations from many pulsars, leveraging the common influence of a stochastic background against noise sources, and mines the cross-correlation signature for information on the angular distribution of GW-power. Additionally, I developed several rapid inference techniques applicable to pulsar-timing searches for individual supermassive BH binary
Experimental Limits on Gravitational Waves in the MHz frequency Range
Lanza, Robert Jr.
2015-03-01
This thesis presents the results of a search for gravitational waves in the 1-11MHz frequency range using dual power-recycled Michelson laser interferometers at Fermi National Accelerator Laboratory. An unprecedented level of sensitivity to gravitational waves in this frequency range has been achieved by cross-correlating the output fluctuations of two identical and colocated 40m long interferometers. This technique produces sensitivities better than two orders of magnitude below the quantum shot-noise limit, within integration times of less than 1 hour. 95% confidence level upper limits are placed on the strain amplitude of MHz frequency gravitational waves at the 10^{-21} Hz^{-1/2} level, constituting the best direct limits to date at these frequencies. For gravitational wave power distributed over this frequency range, a broadband upper limit of 2.4 x 10^{-21}Hz^{-1/2} at 95% confidence level is also obtained. This thesis covers the detector technology, the commissioning and calibration of the instrument, the statistical data analysis, and the gravitational wave limit results. Particular attention is paid to the end-to-end calibration of the instrument’s sensitivity to differential arm length motion, and so to gravitational wave strain. A detailed statistical analysis of the data is presented as well.
Response of a Doppler canceling system to plane gravitational waves
NASA Technical Reports Server (NTRS)
Caporali, A.
1982-01-01
This paper discusses the interaction of long periodic gravitational waves with a three-link microwave system known as the Doppler canceling system. This system, which was developed for a gravitational red-shift experiment, uses one-way and two-way Doppler information to construct the beat signal of two reference oscillators moving with respect to each other. The geometric-optics approximation is used to derive the frequency shift produced on a light signal propagating in a gravitational-wave space-time. The signature left on the Doppler-cancelled beat by bursts and continuous gravitational waves is analyzed. A comparison is made between the response to gravitational waves of the Doppler canceling system and that of a (NASA) Doppler tracking system which employs two-way, round-trip radio waves. A threefold repetition of the gravitational wave form is found to be a common feature of the response functions of both systems. These two functions otherwise exhibit interesting differences.
Lepton asymmetry in the primordial gravitational wave spectrum
Ichiki, Kiyotomo; Yamaguchi, Masahide; Yokoyama, Jun'Ichi
2007-04-15
Effects of neutrino free streaming are evaluated on the primordial spectrum of gravitational radiation taking both neutrino chemical potential and masses into account. The former or the lepton asymmetry induces two competitive effects, namely, to increase anisotropic stress, which damps the gravitational wave more, and to delay the matter-radiation equality time, which reduces the damping. The latter effect is more prominent and a large lepton asymmetry would reduce the damping. We may thereby be able to measure the magnitude of lepton asymmetry from the primordial gravitational wave spectrum.
PREFACE: 14th Gravitational Waves Data Analysis Workshop
NASA Astrophysics Data System (ADS)
Ricci, Fulvio
2010-04-01
The 14th Gravitational Wave Data Analysis Workshop (GWDAW-14) is the last of a long series of annual meetings dedicated to the GW data analysis. This time the workshop was held at the Department of Physics of the University of Rome "Sapienza" and its scientic focus was on strengthening the connection among the gravitational wave and other astrophysical communities. Thus, a significant fraction of the workshop was dedicated to explore the potentialities of the multimessanger astronomy and in particular on the emerging neutrino observatories in conjunction with the GW observations. Moreover, several contributions were devoted to technical details of the analysis of real data from interferometric detectors, aimed at the improvement of the data quality for increasing the confidence in the detection of the first GW event. On the base of these techniques new GW upper limits on the strength of continuous signals from neutron stars and on stochastic background as the event rates of burst and inspiral signals have been set. As chairman of this workshop, I would like to thank the members of the organizing and scientic committees and all the participants which have been the crucial actors of the workshop success. Some of the talks presented during the conference appear in the special issue of Classical and Quantum Gravity, while remaining talks from the symposium are published in this companion volume of Journal of Physics: Conference Series. The ensemble of all these contributions represents the most up-to-date papers on the topics covered by the meeting and, it provides valuable details about current work. Finally , I would also like to thank the institutions and the sponsor that made this meeting possible: University of Rome La Sapienza Italian National Institute of Nuclear Physics - INFN Italian National Institute of Astrophyiscs - INAF University of Rome Tor Vergata University of Sannio E4-Computing Engineering s.p.a. Fulvio Ricci University of La Sapienza and INFN
Design and performance of high laser power interferometers for gravitational-wave detection
NASA Astrophysics Data System (ADS)
Dooley, Katherine Laird
A prediction of Einstein's general theory of relativity, gravitational waves (GWs) are perturbations of the flat space-time Minkowski metric that travel at the speed of light. Indirectly measured by Hulse and Taylor in the 1970s through the energy they carried away from a binary pulsar system, gravitational waves have yet to be detected directly. The Laser Interferometer Gravitational-wave Observatory (LIGO) is part of a global network of gravitational-wave detectors that seeks to detect directly gravitational waves and to study their sources. LIGO operates on the principle of measuring the gravitational wave's physical signature of a strain, or relative displacement of inertial masses. An extremely small effect whose biggest of expected transient signals on Earth is on the order of one part in 1023, gravitational-wave strain can only be measured by detectors so sensitive to displacement as to encounter the effects of quantum physics. To improve their sensitivities and to demonstrate advanced technologies, the LIGO observatories in Hanford, WA and Livingston, LA underwent an upgrade between fall 2007 and summer 2009 called Enhanced LIGO. This study focuses on the experimental challenges of one of the goals of the upgrade: operating at an increased laser power. I present the design and characterization of two of the interferometer subsystems that are critical for the path towards higher laser power: the Input Optics (IO) and the Angular Sensing and Control (ASC) subsystems. The IO required a new design so its optical components would not be susceptible to high power effects such as thermal lensing or thermal beam drift. The ASC required a new design in order to address static instabilities of the arm cavities caused by increased radiation pressure. In all, I demonstrate the capability of an interferometric GW detector to operate at several times the highest of laser powers previously used. (Full text of this dissertation may be available via the University of
Gravitational wave background from binary systems
Rosado, Pablo A.
2011-10-15
Basic aspects of the background of gravitational waves and its mathematical characterization are reviewed. The spectral energy density parameter {Omega}(f), commonly used as a quantifier of the background, is derived for an ensemble of many identical sources emitting at different times and locations. For such an ensemble, {Omega}(f) is generalized to account for the duration of the signals and of the observation, so that one can distinguish the resolvable and unresolvable parts of the background. The unresolvable part, often called confusion noise or stochastic background, is made by signals that cannot be either individually identified or subtracted out of the data. To account for the resolvability of the background, the overlap function is introduced. This function is a generalization of the duty cycle, which has been commonly used in the literature, in some cases leading to incorrect results. The spectra produced by binary systems (stellar binaries and massive black hole binaries) are presented over the frequencies of all existing and planned detectors. A semi-analytical formula for {Omega}(f) is derived in the case of stellar binaries (containing white dwarfs, neutron stars or stellar-mass black holes). Besides a realistic expectation of the level of background, upper and lower limits are given, to account for the uncertainties in some astrophysical parameters such as binary coalescence rates. One interesting result concerns all current and planned ground-based detectors (including the Einstein Telescope). In their frequency range, the background of binaries is resolvable and only sporadically present. In other words, there is no stochastic background of binaries for ground-based detectors.
The potential for very high-frequency gravitational wave detection
NASA Astrophysics Data System (ADS)
Cruise, A. M.
2012-05-01
The science case for observing gravitational waves at frequencies in the millihertz-kilohertz range using LIGO, VIRGO, GEO600 or LISA is very strong and the first results are expected at these frequencies. However, as gravitational wave astronomy progresses beyond the first detections, other frequency bands may be worth exploring. Early predictions of gravitational wave emission from discrete sources at very much higher frequencies (megahertz and above) have been published and more recent studies of cosmological signals from inflation, Kaluza-Klein modes from gravitational interactions in brane worlds and plasma instabilities surrounding violent astrophysical events, are all possible sources. This communication examines current observational possibilities and the detector technology required to make meaningful observations at these frequencies.
Pulsar timing arrays: the promise of gravitational wave detection.
Lommen, Andrea N
2015-12-01
We describe the history, methods, tools, and challenges of using pulsars to detect gravitational waves. Pulsars act as celestial clocks detecting gravitational perturbations in space-time at wavelengths of light-years. The field is poised to make its first detection of nanohertz gravitational waves in the next 10 years. Controversies remain over how far we can reduce the noise in the pulsars, how many pulsars should be in the array, what kind of source we will detect first, and how we can best accommodate our large bandwidth systems. We conclude by considering the important question of how to plan for a post-detection era, beyond the first detection of gravitational waves.
Coauthor Group Development among Scientists Involved in Gravitational Wave Research
NASA Astrophysics Data System (ADS)
Kishel, Deane Alexius
Nicholas Mullins has investigated structures imposed on scientific investigators by four social relationships involving communication--informal communication, coauthorship, apprenticeship, and colleagueship. It has been shown that these structures go through four distinct stages: normal, network, cluster, and specialty. Within the increase in coauthorship in science during this century there is a possibility that one might be able to identify the stages of Mullins's model by investigating the structures imposed on a set of authors by the coauthor relationship alone. This study examines the literature of gravitational wave physics. The subject area is likely to have undergone changes which fit the stages of Mullins's model. Techniques associated with graph theory, the Brillouin information measure, the index of centrality, and other biblometric measures are used to analyze the coauthor structures and to determine if the coauthor relationship is sufficient to identify the stages which are anticipated by the model.
Learning about Black-Hole Formation from Gravitational Waves
NASA Astrophysics Data System (ADS)
Kesden, Michael H.
2017-01-01
The first observing run of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) discovered gravitational waves from two binary black-hole mergers. Although astrophysical black holes are simple objects fully characterized by their masses and spins, key features of binary black-hole formation such as mass transfer, natal kicks, and common-envelope evolution can misalign black-hole spins with the orbital angular momentum of the binary. These misaligned spins will precess as gravitational-wave emission causes the black holes to inspiral to separations at which the waves are detectable by observatories like LIGO. Spin precession modulates the amplitude and frequency of the gravitational waves observed by LIGO, allowing it to not only test general relativity but also reveal the secrets of black-hole formation. This talk will briefly describe those elements of binary black-hole formation responsible for initial spin misalignments, how spin precession and radiation reaction in general relativity determine how spins evolve from formation until the black holes enter LIGO’s sensitivity band, and how spin-induced gravitational-wave modulation in band can be used as a diagnostic of black-hole formation.
Towards robust detection of gravitational waves by pulsar timing
NASA Astrophysics Data System (ADS)
Cornish, Neil J.; Sampson, Laura
2016-01-01
Precision timing of highly stable milli-second pulsars is a promising technique for detecting very low frequency sources of gravitational waves. In any one pulsar, the gravitational wave signal appears as an additional source of timing noise, and it is only by considering the coherent response across a network of pulsars that the signal can be distinguished from other sources of noise. In the limit where there are many gravitational wave sources, or in the limit where there are many pulsars in the array, the waves produce a unique tensor correlation pattern that depends only on the angular separation of each pulsar pair. It is this distinct fingerprint that is used to search for gravitational waves using pulsar timing arrays. Here we consider how the prospects for detection are diminished when there are a finite number of signals and pulsars, which breaks the statistical isotropy of the timing array and of the gravitational wave sky. We also study the use of "sky-scrambles'' to break the signal correlations in the data as a way to increase confidence in a detection.
Into the Lair: Gravitational-wave Signatures of Dark Matter
NASA Astrophysics Data System (ADS)
Macedo, Caio F. B.; Pani, Paolo; Cardoso, Vitor; Crispino, Luís C. B.
2013-09-01
The nature and properties of dark matter (DM) are both outstanding issues in physics. Besides clustering in halos, the universal character of gravity implies that self-gravitating compact DM configurations—predicted by various models—might be spread throughout the universe. Their astrophysical signature can be used to probe fundamental particle physics, or to test alternative descriptions of compact objects in active galactic nuclei. Here, we discuss the most promising dissection tool of such configurations: the inspiral of a compact stellar-size object and consequent gravitational-wave (GW) emission. The inward motion of this "test probe" encodes unique information about the nature of the supermassive configuration. When the probe travels through some compact region we show, within a Newtonian approximation, that the quasi-adiabatic inspiral is mainly driven by DM accretion and by dynamical friction, rather than by radiation reaction. When accretion dominates, the frequency and amplitude of the GW signal produced during the latest stages of the inspiral are nearly constant. In the exterior region we study a model in which the inspiral is driven by GW and scalar-wave emission, described at a fully relativistic level. Resonances in the energy flux appear whenever the orbital frequency matches the effective mass of the DM particle, corresponding to the excitation of the central object's quasinormal frequencies. Unexpectedly, these resonances can lead to large dephasing with respect to standard inspiral templates, to such an extent as to prevent detection with matched filtering techniques. We discuss some observational consequences of these effects for GW detection.
Resonant mode for gravitational wave detectors based on atom interferometry
NASA Astrophysics Data System (ADS)
Graham, Peter W.; Hogan, Jason M.; Kasevich, Mark A.; Rajendran, Surjeet
2016-11-01
We describe an atom interferometric gravitational wave detector design that can operate in a resonant mode for increased sensitivity. By oscillating the positions of the atomic wave packets, this resonant detection mode allows for coherently enhanced, narrow-band sensitivity at target frequencies. The proposed detector is flexible and can be rapidly switched between broadband and narrow-band detection modes. For instance, a binary discovered in broadband mode can subsequently be studied further as the inspiral evolves by using a tailored narrow-band detector response. In addition to functioning like a lock-in amplifier for astrophysical events, the enhanced sensitivity of the resonant approach also opens up the possibility of searching for important cosmological signals, including the stochastic gravitational wave background produced by inflation. We give an example of detector parameters which would allow detection of inflationary gravitational waves down to ΩGW˜10-14 for a two-satellite space-based detector.
Studies on the high-energy follow-up of gravitational wave transient events
NASA Astrophysics Data System (ADS)
Razzano, Massimiliano; Patricelli, Barbara; Cella, Giancarlo; Fidecaro, Francesco; Pian, Elena; Stamerra, Antonio; Branchesi, Marica
2016-05-01
Second-generation gravitational wave interferometers, such as Advanced LIGO and Advanced Virgo, will soon reach sensitivities sufficient to first detect gravitational waves and open a new era in the multi-messenger investigations of the cosmos. The most violent and energetic astrophysical phenomena, including the mergers of compact objects or the core collapse of massive stars, are promising sources of gravitational waves, and are thought to be connected with transient phenomena such as Gamma Ray Bursts and supernovae. Combined observations of gravitational and electromagnetic signals from these events will thus provide a unique opportunity to unveil their progenitors and study the physics of compact objects. In particular, gamma-ray ground-based and space observatories such as Fermi or the Air Cherenkov Telescopes will be crucial to observe the high-energy electromagnetic counterparts of transient gravitational wave signals and provide a robust identification based on a precise sky localization. We will report on our studies of possible joint observation strategies carried on by gravitational interferometers and gamma-ray telescopes, with particular attention to the high-energy follow-up of Gamma Ray Bursts.
NASA Astrophysics Data System (ADS)
Cavaglia, Marco; Hendry, M.; Ingram, D.; Milde, S.; Pandian, S. R.; Reitze, D.; Riles, K.; Schutz, B.; Stuver, A. L.; Summerscales, T.; Ugolini, D.; Thacker, J.; Vallisneri, M.; Zermeno, A.
2008-05-01
The nascent field of gravitational wave astronomy offers many opportunities for effective and inspirational astronomy outreach. Gravitational waves, the `ripples in spacetime' predicted by Einstein's general theory of relativity, are produced by some of the most energetic and dramatic phenomena in the cosmos, including black holes, neutron stars and supernovae - and their discovery should help to address a number of fundamental questions in physics, from the evolution of stars and galaxies to the origin of dark energy and the nature of spacetime itself. Moreover, the cutting-edge technology developed to search for gravitational waves is pushing back the frontiers of many fields, from lasers and materials science to high performance computing, and thus provides a powerful showcase for the attractions and challenges of a career in science and engineering. For several years a worldwide network of ground-based laser interferometric gravitational wave detectors, built and run by the LIGO Scientific Collaboration, has been fully operational. These detectors are already among the most sensitive scientific instruments on the planet but in the next few years their sensitivity will achieve further significant improvement. Those developments promise to open an exciting new window on the Universe, heralding the arrival of gravitational wave astronomy as a revolutionary, new observational field. In this poster we describe the extensive program of public outreach activities already undertaken by the LIGO Scientific Collaboration, and a number of special events which we are planning for IYA2009. These activities include: * programs at Science Centers and Observatory Visitor Centers * programs on gravitational wave astronomy for the classroom, across the K-12 spectrum * interdisciplinary events linking gravitational wave astronomy to music and the visual arts * research experiences for schools and citizens through the highly successful `Einstein@Home' program.
A Physical Model for Gravitation and Inertia
NASA Astrophysics Data System (ADS)
Rasor, Ned
2011-11-01
A physical/analytical model of gravitation and inertia is described. The model is based on proportional expansion of the universe and its contents, along with special relativistic time delay within nucleons. An expression of the gravitational constant G is derived from the model in terms of fundamental constants and properties without adjustable parameters, [ G=he^2c^2 1pt 1ptτu(mpme)^3/2=6.67x10-8cm^3g.s^2 ] where h = Planck constant, e = electronic charge, c = speed of light, mp and me are the nucleonic and electronic masses, and τu= age of the universe. The value τu = 13.6 Gy that corresponds with the accepted value of G shown is within the uncertainty of the empirical value ofτu currently estimated from cosmic ray background and other astronomical data. A modified Newtonian dynamics and other relationships derived from the model are consistent quantitatively and functionally with a variety of observed astronomical data, some of which have been considered previously to be anomalous or based on dark matter.
Astrophysical Prior Information and Gravitational-wave Parameter Estimation
NASA Astrophysics Data System (ADS)
Pankow, Chris; Sampson, Laura; Perri, Leah; Chase, Eve; Coughlin, Scott; Zevin, Michael; Kalogera, Vassiliki
2017-01-01
The detection of electromagnetic counterparts to gravitational waves (GWs) has great promise for the investigation of many scientific questions. While it is well known that certain orientation parameters can reduce uncertainty in other related parameters, it was also hoped that the detection of an electromagnetic signal in conjunction with a GW could augment the measurement precision of the mass and spin from the gravitational signal itself. That is, knowledge of the sky location, inclination, and redshift of a binary could break degeneracies between these extrinsic, coordinate-dependent parameters and the physical parameters that are intrinsic to the binary. In this paper, we investigate this issue by assuming perfect knowledge of extrinsic parameters, and assessing the maximal impact of this knowledge on our ability to extract intrinsic parameters. We recover similar gains in extrinsic recovery to earlier work; however, we find only modest improvements in a few intrinsic parameters—namely the primary component’s spin. We thus conclude that, even in the best case, the use of additional information from electromagnetic observations does not improve the measurement of the intrinsic parameters significantly.
Projected constraints on Lorentz-violating gravity with gravitational waves
NASA Astrophysics Data System (ADS)
Hansen, Devin; Yunes, Nicolás; Yagi, Kent
2015-04-01
Gravitational waves are excellent tools to probe the foundations of general relativity in the strongly dynamical and nonlinear regime. One such foundation is Lorentz symmetry, which can be broken in the gravitational sector by the existence of a preferred time direction and, thus, a preferred frame at each spacetime point. This leads to a modification in the orbital decay rate of binary systems, and also in the generation and chirping of their associated gravitational waves. Here we study whether waves emitted in the late, quasicircular inspiral of nonspinning, neutron star binaries can place competitive constraints on two proxies of gravitational Lorentz violation: Einstein-Æther theory and khronometric gravity. We model the waves in the small-coupling (or decoupling) limit and in the post-Newtonian approximation, by perturbatively solving the field equations in small deformations from general relativity and in the small-velocity or weak-gravity approximation. We assume that a gravitational wave consistent with general relativity has been detected with second- and third-generation, ground-based detectors, and with the proposed space-based mission DECIGO, with and without coincident electromagnetic counterparts. Without a counterpart, a detection consistent with general relativity can only place competitive constraints on gravitational Lorentz violation when using future, third-generation or space-based instruments. On the other hand, a single counterpart is enough to place constraints that are 10 orders of magnitude more stringent than current binary pulsar bounds, even when using second-generation detectors. This is because Lorentz violation forces the group velocity of gravitational waves to be different from that of light, and this difference can be very accurately constrained with coincident observations.
Gravitational-wave probe of effective quantum gravity
Alexander, Stephon; Finn, Lee Samuel; Yunes, Nicolas
2008-09-15
All modern routes leading to a quantum theory of gravity - i.e., perturbative quantum gravitational one-loop exact correction to the global chiral current in the standard model, string theory, and loop quantum gravity - require modification of the classical Einstein-Hilbert action for the spacetime metric by the addition of a parity-violating Chern-Simons term. The introduction of such a term leads to spacetimes that manifest an amplitude birefringence in the propagation of gravitational waves. While the degree of birefringence may be intrinsically small, its effects on a gravitational wave accumulate as the wave propagates. Observation of gravitational waves that have propagated over cosmological distances may allow the measurement of even a small birefringence, providing evidence of quantum gravitational effects. The proposed Laser Interferometer Space Antenna (LISA) will be sensitive enough to observe the gravitational waves from sources at cosmological distances great enough that interesting bounds on the Chern-Simons coupling may be found. Here we evaluate the effect of a Chern-Simons induced spacetime birefringence to the propagation of gravitational waves from such systems. Focusing attention on the gravitational waves from coalescing binary black holes systems, which LISA will be capable of observing at redshifts approaching 30, we find that the signature of Chern-Simons gravity is a time-dependent change in the apparent orientation of the binary's orbital angular momentum with respect to the observer line-of-sight, with the magnitude of change reflecting the integrated history of the Chern-Simons coupling over the worldline of the radiation wave front. While spin-orbit coupling in the binary system will also lead to an evolution of the system's orbital angular momentum, the time dependence and other details of this real effect are different than the apparent effect produced by Chern-Simons birefringence, allowing the two effects to be separately identified
Simon, Joseph; Polin, Abigail; Lommen, Andrea; Christy, B; Stappers, Ben; Finn, Lee Samuel; Jenet, F. A.
2014-03-20
The steadily improving sensitivity of pulsar timing arrays (PTAs) suggests that gravitational waves (GWs) from supermassive black hole binary (SMBHB) systems in the nearby universe will be detectable sometime during the next decade. Currently, PTAs assume an equal probability of detection from every sky position, but as evidence grows for a non-isotropic distribution of sources, is there a most likely sky position for a detectable single source of GWs? In this paper, a collection of Galactic catalogs is used to calculate various metrics related to the detectability of a single GW source resolvable above a GW background, assuming that every galaxy has the same probability of containing an SMBHB. Our analyses of these data reveal small probabilities that one of these sources is currently in the PTA band, but as sensitivity is improved regions of consistent probability density are found in predictable locations, specifically around local galaxy clusters.
The Gravitational-Wave Universe seen by Pulsar Timing Arrays
NASA Astrophysics Data System (ADS)
Mingarelli, Chiara M. F.; International Pulsar Timing Array
2017-01-01
Galaxy mergers are a standard aspect of galaxy formation and evolution, and most (likely all) large galaxies contain supermassive black holes. As part of the merging process, the supermassive black holes should in-spiral together and eventually merge, generating a background of gravitational radiation in the nanohertz to microhertz regime. Processes in the early Universe such as relic gravitational waves and cosmic strings may also generate gravitational radiation in the same frequency band. An array of precisely timed pulsars spread across the sky can form a galactic-scale gravitational wave detector in the nanohertz band. I describe the current efforts to develop and extend the pulsar timing array concept, together with recent limits which have emerged from North American and international efforts to constrain astrophysical phenomena at the heart of supermassive black hole mergers.
Observation of Gravitational Waves from a Binary Black Hole Merger.
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Biscans, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blair, C D; Blair, D G; Blair, R M; Bloemen, S; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bogan, C; Bohe, A; Bojtos, P; Bond, C; Bondu, F; Bonnand, R; Boom, B A; Bork, R; Boschi, V; Bose, S; Bouffanais, Y; Bozzi, A; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Brillet, A; Brinkmann, M; Brisson, V; Brockill, P; Brooks, A F; Brown, D A; Brown, D D; Brown, N M; Buchanan, C C; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Byer, R L; Cabero, M; Cadonati, L; Cagnoli, G; Cahillane, C; Calderón Bustillo, J; Callister, T; Calloni, E; Camp, J B; Cannon, K C; Cao, J; Capano, C D; Capocasa, E; Carbognani, F; Caride, S; Casanueva Diaz, J; Casentini, C; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C B; Cerboni Baiardi, L; Cerretani, G; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chan, M; Chao, S; Charlton, P; Chassande-Mottin, E; 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Ghosh, Archisman; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, K; Glaefke, A; Gleason, J R; Goetz, E; Goetz, R; Gondan, L; González, G; Gonzalez Castro, J M; Gopakumar, A; Gordon, N A; Gorodetsky, M L; Gossan, S E; Gosselin, M; Gouaty, R; Graef, C; Graff, P B; Granata, M; Grant, A; Gras, S; Gray, C; Greco, G; Green, A C; Greenhalgh, R J S; Groot, P; Grote, H; Grunewald, S; Guidi, G M; Guo, X; Gupta, A; Gupta, M K; Gushwa, K E; Gustafson, E K; Gustafson, R; Hacker, J J; Hall, B R; Hall, E D; Hammond, G; Haney, M; Hanke, M M; Hanks, J; Hanna, C; Hannam, M D; Hanson, J; Hardwick, T; Harms, J; Harry, G M; Harry, I W; Hart, M J; Hartman, M T; Haster, C-J; Haughian, K; Healy, J; Heefner, J; Heidmann, A; Heintze, M C; Heinzel, G; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Hennig, J; Heptonstall, A W; Heurs, M; Hild, S; Hoak, D; Hodge, K A; Hofman, D; Hollitt, S E; Holt, K; Holz, D E; Hopkins, P; Hosken, D J; Hough, J; Houston, E A; Howell, E J; Hu, Y M; Huang, S; Huerta, E A; Huet, D; Hughey, B; Husa, S; Huttner, S H; Huynh-Dinh, T; Idrisy, A; Indik, N; Ingram, D R; Inta, R; Isa, H N; Isac, J-M; Isi, M; Islas, G; Isogai, T; Iyer, B R; Izumi, K; Jacobson, M B; Jacqmin, T; Jang, H; Jani, K; Jaranowski, P; Jawahar, S; Jiménez-Forteza, F; Johnson, W W; Johnson-McDaniel, N K; Jones, D I; Jones, R; Jonker, R J G; Ju, L; Haris, K; Kalaghatgi, C V; Kalogera, V; Kandhasamy, S; Kang, G; Kanner, J B; Karki, S; Kasprzack, M; Katsavounidis, E; Katzman, W; Kaufer, S; Kaur, T; Kawabe, K; Kawazoe, F; Kéfélian, F; Kehl, M S; Keitel, D; Kelley, D B; Kells, W; Kennedy, R; Keppel, D G; Key, J S; Khalaidovski, A; Khalili, F Y; Khan, I; Khan, S; Khan, Z; Khazanov, E A; Kijbunchoo, N; Kim, C; Kim, J; Kim, K; Kim, Nam-Gyu; Kim, Namjun; Kim, Y-M; King, E J; King, P J; Kinzel, D L; Kissel, J S; Kleybolte, L; Klimenko, S; Koehlenbeck, S M; Kokeyama, K; Koley, S; Kondrashov, V; Kontos, A; Koranda, S; Korobko, M; Korth, W Z; Kowalska, I; Kozak, D B; Kringel, V; Krishnan, B; Królak, A; Krueger, C; Kuehn, G; Kumar, P; Kumar, R; Kuo, L; Kutynia, A; Kwee, P; Lackey, B D; Landry, M; Lange, J; Lantz, B; Lasky, P D; Lazzarini, A; Lazzaro, C; Leaci, P; Leavey, S; Lebigot, E O; Lee, C H; Lee, H K; Lee, H M; Lee, K; Lenon, A; Leonardi, M; Leong, J R; Leroy, N; Letendre, N; Levin, Y; Levine, B M; Li, T G F; Libson, A; Littenberg, T B; Lockerbie, N A; Logue, J; Lombardi, A L; London, L T; Lord, J E; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J D; Lousto, C O; Lovelace, G; Lück, H; Lundgren, A P; Luo, J; Lynch, R; Ma, Y; MacDonald, T; Machenschalk, B; MacInnis, M; Macleod, D M; Magaña-Sandoval, F; Magee, R M; Mageswaran, M; Majorana, E; Maksimovic, I; Malvezzi, V; Man, N; Mandel, I; Mandic, V; Mangano, V; Mansell, G L; Manske, M; Mantovani, M; Marchesoni, F; Marion, F; Márka, S; Márka, Z; Markosyan, A S; Maros, E; Martelli, F; Martellini, L; Martin, I W; Martin, R M; Martynov, D V; Marx, J N; Mason, K; Masserot, A; Massinger, T J; Masso-Reid, M; Matichard, F; Matone, L; 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Wimmer, M H; Winkelmann, L; Winkler, W; Wipf, C C; Wiseman, A G; Wittel, H; Woan, G; Worden, J; Wright, J L; Wu, G; Yablon, J; Yakushin, I; Yam, W; Yamamoto, H; Yancey, C C; Yap, M J; Yu, H; Yvert, M; Zadrożny, A; Zangrando, L; Zanolin, M; Zendri, J-P; Zevin, M; Zhang, F; Zhang, L; Zhang, M; Zhang, Y; Zhao, C; Zhou, M; Zhou, Z; Zhu, X J; Zucker, M E; Zuraw, S E; Zweizig, J
2016-02-12
On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160) Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.
Low-Frequency Gravitational Wave Searches Using Spacecraft Doppler Tracking.
Armstrong, J W
2006-01-01
This paper discusses spacecraft Doppler tracking, the current-generation detector technology used in the low-frequency (∼millihertz) gravitational wave band. In the Doppler method the earth and a distant spacecraft act as free test masses with a ground-based precision Doppler tracking system continuously monitoring the earth-spacecraft relative dimensionless velocity 2Δv/c = Δν/ν0, where Δν is the Doppler shift and ν0 is the radio link carrier frequency. A gravitational wave having strain amplitude h incident on the earth-spacecraft system causes perturbations of order h in the time series of Δν/ν0. Unlike other detectors, the ∼ 1-10 AU earth-spacecraft separation makes the detector large compared with millihertz-band gravitational wavelengths, and thus times-of-flight of signals and radio waves through the apparatus are important. A burst signal, for example, is time-resolved into a characteristic signature: three discrete events in the Doppler time series. I discuss here the principles of operation of this detector (emphasizing transfer functions of gravitational wave signals and the principal noises to the Doppler time series), some data analysis techniques, experiments to date, and illustrations of sensitivity and current detector performance. I conclude with a discussion of how gravitational wave sensitivity can be improved in the low-frequency band.
Effects of finite-time singularities on gravitational waves
NASA Astrophysics Data System (ADS)
Kleidis, K.; Oikonomou, V. K.
2016-10-01
We analyze the impact of finite-time singularities on gravitational waves, in the context of F(R) gravity. We investigate which singularities are allowed to occur during the inflationary era, when gravitational waves are considered, and we discuss the quantitative implications of each allowed singularity. As we show, only a pressure singularity, the so-called Type II and also a Type IV singularity are allowed to occur during the inflationary era. In the case of a Type II, the resulting amplitude of the gravitational wave is zero or almost zero, hence this pressure singularity has a significant impact on the primordial gravitational waves. The case of a Type IV singularity is more interesting since as we show, the singularity has no effect on the amplitude of the gravitational waves. Therefore, this result combined with the fact that the Type IV singularity affects only the dynamics of inflation, leads to the conclusion that the Universe passes smoothly through a Type IV singularity.
Observation of Gravitational Waves from a Binary Black Hole Merger
NASA Astrophysics Data System (ADS)
Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Arain, M. A.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Belczynski, C.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Bustillo, J. Calderón; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Diaz, J. Casanueva; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Baiardi, L. Cerboni; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cruise, A. M.; Cumming, A.; Cunningham, L.; Cuoco, E.; Canton, T. Dal; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Da Silva Costa, C. F.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; De, S.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; DeRosa, R. T.; De Rosa, R.; DeSalvo, R.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Finn, L. S.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fong, H.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frede, M.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gatto, A.; Gaur, G.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Gleason, J. R.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Castro, J. M. Gonzalez; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Greenhalgh, R. J. S.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heefner, J.; Heidmann, A.; Heintze, M. C.; Heinzel, G.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacobson, M. B.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Johnson-McDaniel, N. K.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Keppel, D. G.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, C.; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Koranda, S.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Kwee, P.; Lackey, B. D.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Logue, J.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C. O.; Lovelace, G.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pan, Y.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O.; Pichot, M.; Pickenpack, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J. H.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Ramet, C. R.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sampson, L. M.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, G. H.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shaffer, T.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, M. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stevenson, S. P.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Waldman, S. J.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, H.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Willems, P. A.; Williams, L.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkelmann, L.; Winkler, W.; Wipf, C. C.; Wiseman, A. G.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yakushin, I.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration
2016-02-01
On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 ×10-21. It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1 σ . The source lies at a luminosity distance of 41 0-180+160 Mpc corresponding to a redshift z =0.0 9-0.04+0.03 . In the source frame, the initial black hole masses are 3 6-4+5M⊙ and 2 9-4+4M⊙ , and the final black hole mass is 6 2-4+4M⊙ , with 3. 0-0.5+0.5M⊙ c2 radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.
NASA Astrophysics Data System (ADS)
Collett, Thomas E.; Bacon, David
2017-03-01
Probing the relative speeds of gravitational waves and light acts as an important test of general relativity and alternative theories of gravity. Measuring the arrival time of gravitational waves (GWs) and electromagnetic (EM) counterparts can be used to measure the relative speeds, but only if the intrinsic time lag between emission of the photons and gravitational waves is well understood. Here we suggest a method that does not make such an assumption, using future strongly lensed GW events and EM counterparts; Biesiada et al. [J. Cosmol. Astropart. Phys.10 (2014) 080, 10.1088/1475-7516/2014/10/080] forecast that 50-100 strongly lensed GW events will be observed each year with the Einstein Telescope. A single strongly lensed GW event would produce robust constraints on cGW/cγ at the 10-7 level, if a high-energy EM counterpart is observed within the field of view of an observing γ -ray burst monitor.
Compact dark matter objects, asteroseismology, and gravitational waves radiated by sun
Pokrovsky, Yu. E.
2015-12-15
The solar surface oscillations observed by Crimean Astrophysical Observatory and Solar Helioseismic Observatory are considered to be excited by a small fraction of Dark Matter in form of Compact Dark Matter Objects (CDMO) in the solar structure. Gravitational Waves (GW) radiated by these CDMO are predicted to be the strongest at the Earth and are easily detectable by European Laser Interferometer Space Antenna or by Gravitational-Wave Observatory “Dulkyn” which can solve two the most challenging tasks in the modern physics: direct detection of GW and DM.
Gravitational waves from fragmentation of a primordial scalar condensate into Q balls.
Kusenko, Alexander; Mazumdar, Anupam
2008-11-21
A generic consequence of supersymmetry is the formation of a scalar condensate along the flat directions of the potential at the end of cosmological inflation. This condensate is usually unstable, and it can fragment into nontopological solitons, Q balls. The gravitational waves produced by the fragmentation can be detected by the Laser Interferometer Space Antenna, Advanced Laser Interferometer Gravitational-Wave Observatory, and Big Bang Observer, which can open an important window to the early Universe and the physics at some very high energy scales.
NASA Technical Reports Server (NTRS)
Blackwell, William C., Jr.
2004-01-01
In this paper space is modeled as a lattice of Compton wave oscillators (CWOs) of near- Planck size. It is shown that gravitation and special relativity emerge from the interaction between particles Compton waves. To develop this CWO model an algorithmic approach was taken, incorporating simple rules of interaction at the Planck-scale developed using well known physical laws. This technique naturally leads to Newton s law of gravitation and a new form of doubly special relativity. The model is in apparent agreement with the holographic principle, and it predicts a cutoff energy for ultrahigh-energy cosmic rays that is consistent with observational data.
Upper limits on a stochastic background of gravitational waves.
Abbott, B; Abbott, R; Adhikari, R; Agresti, J; Ajith, P; Allen, B; Allen, J; Amin, R; Anderson, S B; Anderson, W G; Araya, M; Armandula, H; Ashley, M; Aulbert, C; Babak, S; Balasubramanian, R; Ballmer, S; Barish, B C; Barker, C; Barker, D; Barton, M A; Bayer, K; Belczynski, K; Betzwieser, J; Bhawal, B; Bilenko, I A; Billingsley, G; Black, E; Blackburn, K; Blackburn, L; Bland, B; Bogue, L; Bork, R; Bose, S; Brady, P R; Braginsky, V B; Brau, J E; Brown, D A; Buonanno, A; Busby, D; Butler, W E; Cadonati, L; Cagnoli, G; Camp, J B; Cannizzo, J; Cannon, K; Cardenas, L; Carter, K; Casey, M M; Charlton, P; Chatterji, S; Chen, Y; Chin, D; Christensen, N; Cokelaer, T; Colacino, C N; Coldwell, R; Cook, D; Corbitt, T; Coyne, D; Creighton, J D E; Creighton, T D; Dalrymple, J; D'Ambrosio, E; Danzmann, K; Davies, G; DeBra, D; Dergachev, V; Desai, S; DeSalvo, R; Dhurandar, S; Díaz, M; Di Credico, A; Drever, R W P; Dupuis, R J; Ehrens, P; Etzel, T; Evans, M; Evans, T; Fairhurst, S; Finn, L S; Franzen, K Y; Frey, R E; Fritschel, P; Frolov, V V; Fyffe, M; Ganezer, K S; Garofoli, J; Gholami, I; Giaime, J A; Goda, K; Goggin, L; González, G; Gray, C; Gretarsson, A M; Grimmett, D; Grote, H; Grunewald, S; Guenther, M; Gustafson, R; Hamilton, W O; Hanna, C; Hanson, J; Hardham, C; Harry, G; Heefner, J; Heng, I S; Hewitson, M; Hindman, N; Hoang, P; Hough, J; Hua, W; Ito, M; Itoh, Y; Ivanov, A; Johnson, B; Johnson, W W; Jones, D I; Jones, G; Jones, L; Kalogera, V; Katsavounidis, E; Kawabe, K; Kawamura, S; Kells, W; Khan, A; Kim, C; King, P; Klimenko, S; Koranda, S; Kozak, D; Krishnan, B; Landry, M; Lantz, B; Lazzarini, A; Lei, M; Leonor, I; Libbrecht, K; Lindquist, P; Liu, S; Lormand, M; Lubinski, M; Lück, H; Luna, M; Machenschalk, B; MacInnis, M; Mageswaran, M; Mailand, K; Malec, M; Mandic, V; Marka, S; Maros, E; Mason, K; Matone, L; Mavalvala, N; McCarthy, R; McClelland, D E; McHugh, M; McNabb, J W C; Melissinos, A; Mendell, G; Mercer, R A; Meshkov, S; Messaritaki, E; Messenger, C; Mikhailov, E; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Miyakawa, O; Mohanty, S; Moreno, G; Mossavi, K; Mueller, G; Mukherjee, S; Myers, E; Myers, J; Nash, T; Nocera, F; Noel, J S; O'Reilly, B; O'Shaughnessy, R; Ottaway, D J; Overmier, H; Owen, B J; Pan, Y; Papa, M A; Parameshwaraiah, V; Parameswariah, C; Pedraza, M; Penn, S; Pitkin, M; Prix, R; Quetschke, V; Raab, F; Radkins, H; Rahkola, R; Rakhmanov, M; Rawlins, K; Ray-Majumder, S; Re, V; Regimbau, T; Reitze, D H; Riesen, R; Riles, K; Rivera, B; Robertson, D I; Robertson, N A; Robinson, C; Roddy, S; Rodriguez, A; Rollins, J; Romano, J D; Romie, J; Rowan, S; Rüdiger, A; Ruet, L; Russell, P; Ryan, K; Sandberg, V; Sanders, G H; Sannibale, V; Sarin, P; Sathyaprakash, B S; Saulson, P R; Savage, R; Sazonov, A; Schilling, R; Schofield, R; Schutz, B F; Schwinberg, P; Scott, S M; Seader, S E; Searle, A C; Sears, B; Sellers, D; Sengupta, A S; Shawhan, P; Shoemaker, D H; Sibley, A; Siemens, X; Sigg, D; Sintes, A M; Smith, J; Smith, M R; Spjeld, O; Strain, K A; Strom, D M; Stuver, A; Summerscales, T; Sung, M; Sutton, P J; Tanner, D B; Taylor, R; Thorne, K A; Thorne, K S; Tokmakov, K V; Torres, C; Torrie, C; Traylor, G; Tyler, W; Ugolini, D; Ungarelli, C; Vallisneri, M; van Putten, M; Vass, S; Vecchio, A; Veitch, J; Vorvick, C; Vyachanin, S P; Wallace, L; Ward, H; Ward, R; Watts, K; Webber, D; Weiland, U; Weinstein, A; Weiss, R; Wen, S; Wette, K; Whelan, J T; Whitcomb, S E; Whiting, B F; Wiley, S; Wilkinson, C; Willems, P A; Willke, B; Wilson, A; Winkler, W; Wise, S; Wiseman, A G; Woan, G; Woods, D; Wooley, R; Worden, J; Yakushin, I; Yamamoto, H; Yoshida, S; Zanolin, M; Zhang, L; Zotov, N; Zucker, M; Zweizig, J
2005-11-25
The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of omega0 < 8.4 x 10(-4) in the 69-156 Hz band is approximately 10(5) times lower than the previous result in this frequency range.
Multi-messenger astronomy: gravitational waves, neutrinos, photons, and cosmic rays
NASA Astrophysics Data System (ADS)
Branchesi, Marica
2016-05-01
In the next decade, multi-messenger astronomy will probe the rich physics of transient phenomena in the sky, such as the mergers of neutron stars and/or black holes, gamma-ray bursts, and core-collapse supernovae. The first observations of gravitational waves from the inspiral and merger of a binary black-hole system by the advanced LIGO interferometers marked the onset of gravitational-wave astronomy. The advanced detectors, LIGO and Virgo, observing together with space and ground-based electromagnetic telescopes, and neutrinos and cosmic-ray detectors will offer the great opportunity to explore the Universe through all its messengers. The paper provides a review of the astrophysical sources expected to emit transient multi-messenger signals and the multi-messenger obervational startegies and analysis. Challenges and perspectives of the multi-messenger astronomy are presented highlighting gravitational waves as new messenger.
Gravitational waves from a Weyl-Integrable manifold: A new formalism
NASA Astrophysics Data System (ADS)
Romero, Jesús Martín; Bellini, Mauricio; Madriz Aguilar, José Edgar
2016-09-01
We study the variational principle over an Hilbert-Einstein like action for an extended geometry taking into account torsion and non-metricity. By extending the semi-Riemannian geometry, we obtain an effective energy-momentum tensor which can be interpreted as physical sources. As an application we develop a new manner to obtain the gravitational wave equations on a Weyl-integrable manifold taking into account the non-metricity and non-trivial boundary conditions on the minimization of the action, which can be identified as possible sources for the cosmological constant and provides two different equations for gravitational waves. We examine gravitational waves in a pre-inflationary cosmological model.
Detectability of Gravitational Waves from High-Redshift Binaries.
Rosado, Pablo A; Lasky, Paul D; Thrane, Eric; Zhu, Xingjiang; Mandel, Ilya; Sesana, Alberto
2016-03-11
Recent nondetection of gravitational-wave backgrounds from pulsar timing arrays casts further uncertainty on the evolution of supermassive black hole binaries. We study the capabilities of current gravitational-wave observatories to detect individual binaries and demonstrate that, contrary to conventional wisdom, some are, in principle, detectable throughout the Universe. In particular, a binary with rest-frame mass ≳10^{10}M_{⊙} can be detected by current timing arrays at arbitrarily high redshifts. The same claim will apply for less massive binaries with more sensitive future arrays. As a consequence, future searches for nanohertz gravitational waves could be expanded to target evolving high-redshift binaries. We calculate the maximum distance at which binaries can be observed with pulsar timing arrays and other detectors, properly accounting for redshift and using realistic binary waveforms.
Stochastic gravitational wave background from cold dark matter halos
Carbone, Carmelita; Baccigalupi, Carlo; Matarrese, Sabino
2006-03-15
The current knowledge of cosmological structure formation suggests that Cold Dark Matter (CDM) halos possess a nonspherical density profile, implying that cosmic structures can be potential sources of gravitational waves via power transfer from scalar perturbations to tensor metric modes in the nonlinear regime. By means of a previously developed mathematical formalism and a triaxial collapse model, we numerically estimate the stochastic gravitational-wave background generated by CDM halos during the fully nonlinear stage of their evolution. Our results suggest that the energy density associated with this background is comparable to that produced by primordial tensor modes at frequencies {nu}{approx_equal}10{sup -18}-10{sup -17} Hz if the energy scale of inflation is V{sup 1/4}{approx_equal}1-2x10{sup 15} GeV, and that these gravitational waves could give rise to several cosmological effects, including secondary CMB anisotropy and polarization.
Detectability of Gravitational Waves from High-Redshift Binaries
NASA Astrophysics Data System (ADS)
Rosado, Pablo A.; Lasky, Paul D.; Thrane, Eric; Zhu, Xingjiang; Mandel, Ilya; Sesana, Alberto
2016-03-01
Recent nondetection of gravitational-wave backgrounds from pulsar timing arrays casts further uncertainty on the evolution of supermassive black hole binaries. We study the capabilities of current gravitational-wave observatories to detect individual binaries and demonstrate that, contrary to conventional wisdom, some are, in principle, detectable throughout the Universe. In particular, a binary with rest-frame mass ≳1010M⊙ can be detected by current timing arrays at arbitrarily high redshifts. The same claim will apply for less massive binaries with more sensitive future arrays. As a consequence, future searches for nanohertz gravitational waves could be expanded to target evolving high-redshift binaries. We calculate the maximum distance at which binaries can be observed with pulsar timing arrays and other detectors, properly accounting for redshift and using realistic binary waveforms.
Massive gravitons as dark matter and gravitational waves
NASA Astrophysics Data System (ADS)
Aoki, Katsuki; Mukohyama, Shinji
2016-07-01
We consider the possibility that the massive graviton is a viable candidate for dark matter in the context of bimetric gravity. We first derive the energy-momentum tensor of the massive graviton and show that it indeed behaves as that of dark matter fluid. We then discuss a production mechanism and the present abundance of massive gravitons as dark matter. Since the metric to which ordinary matter fields couple is a linear combination of the two mass eigenstates of bigravity, production of massive gravitons, i.e., the dark matter particles, is inevitably accompanied by generation of massless gravitons, i.e., the gravitational waves. Therefore, in this scenario some information about dark matter in our Universe is encoded in gravitational waves. For instance, if LIGO detects gravitational waves generated by the preheating after inflation, then the massive graviton with the mass of ˜0.01 GeV is a candidate for dark matter.
Progress Toward a Space-Based Gravitational Wave Observatory
NASA Astrophysics Data System (ADS)
Livas, Jeffrey C.; Stebbins, Robin T.
The discovery of binary pulsar PSR 1913+16 by Hulse & Taylor in 1974 established the existence of gravitational waves, for which the 1983 Nobel Prize was awarded. However, the measurement of astrophysical parameters from gravitational waves will open an entirely new spectrum for discovery and understanding of the Universe, not simply a new window in the electromagnetic spectrum like gamma ray telescopes in the 1970s. Two types of ground-based detectors, Advanced LIGO/Virgo and Pulsar Timing Arrays, are expected to directly detect gravitational waves in their respective frequency bands before the end of the decade. However, many of the most exciting sources are in the band from 0.1-100 mHz, accessible only from space due to seismic and gravity gradient noise on Earth. The European Space Agency (ESA) has chosen the 'Gravitational Universe' as the science theme for its L3 Cosmic Visions opportunity, planned for launch in 2034. NASA is planning to participate as a junior partner. Here we summarize progress toward realizing a gravitational wave observatory in space.
Cylindrical gravitational waves in expanding universes: Models for waves from compact sources
Gowdy, Robert H.; Edmonds, B. Douglas
2007-04-15
New boundary conditions are imposed on the familiar cylindrical gravitational wave vacuum spacetimes. The new spacetime family represents cylindrical waves in a flat expanding (Kasner) universe. Space sections are flat and nonconical where the waves have not reached and wave amplitudes fall off more rapidly than they do in Einstein-Rosen solutions, permitting a more regular null inifinity.
Cylindrical gravitational waves in expanding universes: Models for waves from compact sources
NASA Astrophysics Data System (ADS)
Gowdy, Robert H.; Edmonds, B. Douglas
2007-04-01
New boundary conditions are imposed on the familiar cylindrical gravitational wave vacuum spacetimes. The new spacetime family represents cylindrical waves in a flat expanding (Kasner) universe. Space sections are flat and nonconical where the waves have not reached and wave amplitudes fall off more rapidly than they do in Einstein-Rosen solutions, permitting a more regular null inifinity.
Bayesian reconstruction of gravitational wave bursts using chirplets
NASA Astrophysics Data System (ADS)
Millhouse, Margaret; Cornish, Neil; Littenberg, Tyson
2017-01-01
The BayesWave algorithm has been shown to accurately reconstruct unmodeled short duration gravitational wave bursts and to distinguish between astrophysical signals and transient noise events. BayesWave does this by using a variable number of sine-Gaussian (Morlet) wavelets to reconstruct data in multiple interferometers. While the Morlet wavelets can be summed together to produce any possible waveform, there could be other wavelet functions that improve the performance. Because we expect most astrophysical gravitational wave signals to evolve in frequency, modified Morlet wavelets with linear frequency evolution - called chirplets - may better reconstruct signals with fewer wavelets. We compare the performance of BayesWave using Morlet wavelets and chirplets on a variety of simulated signals.
Nonlinear wave breaking in self-gravitating viscoelastic quantum fluid
NASA Astrophysics Data System (ADS)
Mitra, Aniruddha; Roychoudhury, Rajkumar; Bhar, Radhaballav; Khan, Manoranjan
2017-02-01
The stability of a viscoelastic self-gravitating quantum fluid has been studied. Symmetry breaking instability of solitary wave has been observed through 'viscosity modified Ostrovsky equation' in weak gravity limit. In presence of strong gravitational field, the solitary wave breaks into shock waves. Response to a Gaussian perturbation, the system produces quasi-periodic short waves, which in terns predicts the existence of gravito-acoustic quasi-periodic short waves in lower solar corona region. Stability analysis of this dynamical system predicts gravity has the most prominent effect on the phase portraits, therefore, on the stability of the system. The non-existence of chaotic solution has also been observed at long wavelength perturbation through index value theorem.
Space-Based Gravitational-wave Mission Concept Studies
NASA Technical Reports Server (NTRS)
Livas, Jeffrey C.
2012-01-01
The LISA Mission Concept has been under study for over two decades as a spacebased gravitational-wave detector capable of observing astrophysical sources in the 0.0001 to 1 Hz band. The concept has consistently received strong recommendations from various review panels based on the expected science, most recently from the US Astr02010 Decadal Review. Budget constraints have led both the US and European Space agencies to search for lower cost options. We report results from the US effort to explore the tradeoffs between mission cost and science return, and in particular a family of mission concepts referred to as SGO (Space-based Gravitational-wave Observatory).
Dynamics and gravitational wave signature of collapsar formation.
Ott, C D; Reisswig, C; Schnetter, E; O'Connor, E; Sperhake, U; Löffler, F; Diener, P; Abdikamalov, E; Hawke, I; Burrows, A
2011-04-22
We perform 3+1 general relativistic simulations of rotating core collapse in the context of the collapsar model for long gamma-ray bursts. We employ a realistic progenitor, rotation based on results of stellar evolution calculations, and a simplified equation of state. Our simulations track self-consistently collapse, bounce, the postbounce phase, black hole formation, and the subsequent early hyperaccretion phase. We extract gravitational waves from the spacetime curvature and identify a unique gravitational wave signature associated with the early phase of collapsar formation.
What can we learn about cosmic structure from gravitational waves?
NASA Technical Reports Server (NTRS)
Centrella, Joan M.
2003-01-01
Observations of low frequency gravitational waves by the space-based LISA mission will open a new observational window on the early universe and the emergence of structure. LISA will observe the dynamical coalescence of massive black hole binaries at high redshifts, giving an unprecedented look at the merger history of galaxies and the reionization epoch. LISA will also observe gravitational waves from the collapse of supermassive stars to form black holes, and will map the spacetime in the central regions of galaxy cusps at high precision.
GRB as a counterpart for Gravitational Wave detection in LCGT
NASA Astrophysics Data System (ADS)
Kanda, Nobuyuki
2010-10-01
Short Gamma-ray burst (GRB) progenitors are considered as merger of compact star binaries which consist of neutron stars or blackholes. These compact star binaries will radiate a strong gravitational wave in their coalescence, and gravitational wave detectors aim to detect them. We studied the chance probability of coincidence between GRB and GW detection in LCGT detector. Due to omni-directional acceptance of GW detectors, about 75% of GRB events which closer than cosmological redshift z<0.1 are expected to confirm by GW detection.
Listening to the low-frequency gravitational-wave band
NASA Astrophysics Data System (ADS)
Hughes, Scott
2016-03-01
Ground-based gravitational-wave detectors are beginning to explore the high-frequency band of roughly 10 to 1000 Hz. These three decades in frequency represent one of several astrophysically important wavebands. In this talk, I will focus on the astrophysics of the low-frequency band, from roughly 30 microhertz to 0.1 Hz. This band is expected to be particularly rich with very loud sources. I will survey what we expect to be important sources of low-frequency gravitational waves, and review the scientific payoff that would come from measuring them.
MHz gravitational waves from short-term anisotropic inflation
Ito, Asuka; Soda, Jiro
2016-04-18
We reveal the universality of short-term anisotropic inflation. As a demonstration, we study inflation with an exponential type gauge kinetic function which is ubiquitous in models obtained by dimensional reduction from higher dimensional fundamental theory. It turns out that an anisotropic inflation universally takes place in the later stage of conventional inflation. Remarkably, we find that primordial gravitational waves with a peak amplitude around 10{sup −26}∼10{sup −27} are copiously produced in high-frequency bands 10 MHz∼100 MHz. If we could detect such gravitational waves in future, we would be able to probe higher dimensional fundamental theory.
The generation of gravitational waves. II - The postlinear formalism revisited
NASA Technical Reports Server (NTRS)
Crowley, R. J.; Thorne, K. S.
1977-01-01
Two different versions of the Green's function for the scalar wave equation in weakly curved spacetime (one due to DeWitt and DeWitt, the other to Thorne and Kovacs) are compared and contrasted; and their mathematical equivalence is demonstrated. Then the DeWitt-DeWitt Green's function is used to construct several alternative versions of the Thorne-Kovacs postlinear formalism for gravitational-wave generation. Finally it is shown that, in calculations of gravitational bremsstrahlung radiation, some of our versions of the postlinear formalism allow one to treat the interacting bodies as point masses, while others do not.
Spherical gravitational wave detectors: MiniGRAIL and Mario Schenberg
NASA Astrophysics Data System (ADS)
Da Silva Costa, C. F.; Aguiar, O. D.
2014-03-01
Spherical gravitational wave detectors allow the analysis of multiple independent channels and, therefore, are able to determine gravitational wave directions and polarizations. There are two spherical detectors being developed now: MiniGRAIL (Netherlands) and Mario Schenberg (Brazil). Both share the same principle of detection and main features. They have done commissioning runs and shown progress in their development. We have presented here the status of Mario Schenberg. Its transducers have been redesigned for sensitivity improvements. While an offline analysis was already developed for MiniGRAIL, we have investigated a low latency data analysis technique for Mario Schenberg. Both analysis are based on directional detection.
Dynamics and Gravitational Wave Signature of Collapsar Formation
NASA Astrophysics Data System (ADS)
Ott, C. D.; Reisswig, C.; Schnetter, E.; O'Connor, E.; Sperhake, U.; Löffler, F.; Diener, P.; Abdikamalov, E.; Hawke, I.; Burrows, A.
2011-04-01
We perform 3+1 general relativistic simulations of rotating core collapse in the context of the collapsar model for long gamma-ray bursts. We employ a realistic progenitor, rotation based on results of stellar evolution calculations, and a simplified equation of state. Our simulations track self-consistently collapse, bounce, the postbounce phase, black hole formation, and the subsequent early hyperaccretion phase. We extract gravitational waves from the spacetime curvature and identify a unique gravitational wave signature associated with the early phase of collapsar formation.
Gravitational wave bursts from cosmic superstrings with Y-junctions
Binetruy, P.; Bohe, A.; Hertog, T.; Steer, D. A.
2009-12-15
Cosmic superstring loops generically contain strings of different tensions that meet at Y-junctions. These loops evolve nonperiodically in time, and have cusps and kinks that interact with the junctions. We study the effect of junctions on the gravitational wave signal emanating from cosmic string cusps and kinks. We find that earlier results on the strength of individual bursts from cusps and kinks on strings without junctions remain largely unchanged, but junctions give rise to additional contributions to the gravitational wave signal coming from strings expanding at the speed of light at a junction and kinks passing through a junction.
MHz gravitational waves from short-term anisotropic inflation
NASA Astrophysics Data System (ADS)
Ito, Asuka; Soda, Jiro
2016-04-01
We reveal the universality of short-term anisotropic inflation. As a demonstration, we study inflation with an exponential type gauge kinetic function which is ubiquitous in models obtained by dimensional reduction from higher dimensional fundamental theory. It turns out that an anisotropic inflation universally takes place in the later stage of conventional inflation. Remarkably, we find that primordial gravitational waves with a peak amplitude around 10-26~ 10-27 are copiously produced in high-frequency bands 10 MHz~100 MHz. If we could detect such gravitational waves in future, we would be able to probe higher dimensional fundamental theory.
Gravitational waves from double hybrid inflation
NASA Astrophysics Data System (ADS)
Lazarides, G.; Panagiotakopoulos, C.
2015-12-01
We present a two-stage hybrid inflationary scenario in nonminimal supergravity which can predict values of the tensor-to-scalar ratio of the order of a few ×10-2 . For the parameters considered, the underlying supersymmetric particle physics model possesses two inflationary paths, the trivial and the semishifted one. The trivial path is stabilized by supergravity corrections and supports a first stage of inflation with a limited number of e-foldings. The tensor-to-scalar ratio can become appreciable while the value of the scalar spectral index remains acceptable as a result of the competition between the relatively mild supergravity corrections and the strong radiative corrections to the inflationary potential. The additional number of e-foldings required for solving the puzzles of hot big bang cosmology are generated by a second stage of inflation taking place along the semishifted path. This is possible only because the semishifted path is almost perpendicular to the trivial one, and thus not affected by the strong radiative corrections along the trivial path, and also because the supergravity effects remain mild. The requirement that the running of the scalar spectral index remain acceptable limits the possible values of the tensor-to-scalar ratio not to exceed about 5 ×10-2 . Our model predicts the formation of an unstable string-monopole network, which may lead to detectable gravity wave signatures in future space-based laser interferometer observations.
NASA Astrophysics Data System (ADS)
Winterberg, Friedwardt
2016-01-01
An explanation of the quantum-mechanical particle-wave duality is given by the watt-less emission of gravitational waves from a particle described by the Dirac equation. This explanation is possible through the existence of negative energy, and hence negative mass solutions of Einstein's gravitational field equations. They permit to understand the Dirac equation as the equation for a gravitationally bound positive-negative mass (pole-dipole particle) two-body configuration, with the mass of the Dirac particle equal to the positive mass of the gravitational field binding the positive with the negative mass particle, and with the mass particles making a luminal "Zitterbewegung" (quivering motion), emitting a watt-less oscillating positive-negative space curvature wave. It is shown that this thusly produced "Zitterbewegung" reproduces the quantum potential of the Madelung-transformed Schrödinger equation. The watt-less gravitational wave emitted by the quivering particles is conjectured to be de Broglie's pilot wave. The hypothesised connection of the Dirac equation to gravitational wave physics could, with the failure to detect gravitational waves by the LIGO antennas and pulsar timing arrays, give a clue to extended theories of gravity, or a correction of astrophysical models for the generation of such waves.
Cosmic Messengers: Binary Black Holes and Gravitational Waves
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein s equations of general relativity on a computer in order to calculate these wave patterns. For more than 30 years, scientists have tried to compute these wave patterns. However, their computer codes have been plagued by problems that caused them to crash. . This situation has changed dramatically in the past 2 years, with a series of amazing breakthroughs. This talk will take you on this quest for these gravitational wave patterns, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will. be observed by LISA.
Binary Black Holes, Numerical Relativity, and Gravitational Waves
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these wave patterns. For more than 30 years, scientists have tried to compute these wave patterns. However, their computer codes have been plagued by problems that caused them to crash. This situation has changed dramatically in the past 2 years, with a series of amazing breakthroughs. This talk will take you on this quest for these gravitational wave patterns, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LISA
The Suitability of Hybrid Waveforms for Advanced Gravitational Wave Detectors
NASA Astrophysics Data System (ADS)
MacDonald, Ilana; Pfeiffer, H.; Nissanke, S.; Mroue, A.
2013-01-01
General relativity predicts that the coalescence of two compact objects, such as black holes, will produce gravitational radiation; i.e., ripples in the curvature of space-time. Detectors like Advanced LIGO (the Laser Interferometry Gravitational-wave Observatory) are expected to measure such events within the next few years. In order to be able to characterize the gravitational waves they measure, these detectors require accurate waveform models, which can be constructed by fusing an analytical post-Newtonian inspiral waveform with a numerical relativity late-inspiral-merger-ringdown waveform. Numerical relativity, though the most accurate model, is computationally expensive: the longest simulations to date taking several months to run. Post-Newtonian theory, an analytic approximation to General Relativity, is easy to compute but becomes increasingly inaccurate near merger. Because of this trade-off, it is important to determine the optimal length of the numerical waveform, while maintaining the necessary accuracy for gravitational wave detectors. We present a study of the sufficient accuracy of post-Newtonian and numerical relativity waveforms for the most demanding usage case: parameter estimation of strong sources in advanced gravitational wave detectors. We perform a comprehensive analysis of errors that enter such “hybrid waveforms” in the case of equal-mass and unequal mass non-spinning binaries. We also explore the possibility of using these hybrid waveforms as a detection template bank for Advanced LIGO. Accurate hybrids play an important role in investigating the efficiency of gravitational wave search pipelines, as with NINJA (Numerical INJection Analysis); and also in constructing analytical models that span the entire parameter space of binary black hole mass ratios and spins, as with NRAR (Numerical Relativity and Analytic Relativity).
The Suitability of Hybrid Waveforms for Advanced Gravitational Wave Detectors
NASA Astrophysics Data System (ADS)
MacDonald, Ilana; Pfeiffer, H.; Nissanke, S.
2012-01-01
General relativity predicts that the coalescence of two compact objects, such as black holes, will produce gravitational radiation; i.e., ripples in the curvature of space-time. Detectors like Advanced LIGO (the Laser Interferometry Gravitational-wave Observatory) are expected to measure such events within the next few years. In order to be able to characterize the gravitational waves they measure, these detectors require accurate waveform models, which can be constructed by fusing an analytical post-Newtonian inspiral waveform with a numerical relativity late-inspiral-merger-ringdown waveform. Numerical relativity, though the most accurate model, is computationally expensive: the longest simulations to date taking several months to run. Post-Newtonian theory, an analytic approximation to General Relativity, is easy to compute but becomes increasingly inaccurate near merger. Because of this trade-off, it is important to determine the optimal length of the numerical waveform, while maintaining the necessary accuracy for gravitational wave detectors. We present a study of the sufficient accuracy of post-Newtonian and numerical relativity waveforms for the most demanding usage case: parameter estimation of strong sources in advanced gravitational wave detectors. We perform a comprehensive analysis of errors that enter such "hybrid waveforms” in the case of equal-mass non-spinning binaries. Preliminary research has also been done in the case of unequal-mass non-spinning binaries. Accurate hybrids play an important role in investigating the efficiency of gravitational wave search pipelines, as with NINJA (Numerical INJection Analysis); and also in constructing analytical models that span the entire parameter space of binary black hole mass ratios and spins, as with NRAR (Numerical Relativity and Analytic Relativity).
Hussain, Ibrar; Qadir, Asghar; Mahomed, F. M.
2009-06-15
Since gravitational wave spacetimes are time-varying vacuum solutions of Einstein's field equations, there is no unambiguous means to define their energy content. However, Weber and Wheeler had demonstrated that they do impart energy to test particles. There have been various proposals to define the energy content, but they have not met with great success. Here we propose a definition using 'slightly broken' Noether symmetries. We check whether this definition is physically acceptable. The procedure adopted is to appeal to 'approximate symmetries' as defined in Lie analysis and use them in the limit of the exact symmetry holding. A problem is noted with the use of the proposal for plane-fronted gravitational waves. To attain a better understanding of the implications of this proposal we also use an artificially constructed time-varying nonvacuum metric and evaluate its Weyl and stress-energy tensors so as to obtain the gravitational and matter components separately and compare them with the energy content obtained by our proposal. The procedure is also used for cylindrical gravitational wave solutions. The usefulness of the definition is demonstrated by the fact that it leads to a result on whether gravitational waves suffer self-damping.
Lunar LIGO: A new concept in gravitational wave astronomy
NASA Technical Reports Server (NTRS)
Lafave, Norman; Wilson, Thomas L.
1993-01-01
For three decades, physicists have been in search of an elusive phenomenon predicted by Einstein's general theory of relativity; gravitational radiation. These weak vibrations of spacetime have, thus far, eluded conclusive Earth-based detection due in part to insufficient detector sensitivity and noise isolation. The detection of gravitational waves is crucial for two reasons. It would provide further evidence for the validity of Einstein's theory of relativity, the presently accepted theory of gravitation. Furthermore, the ability to identify the location of a source of a detected gravitational wave event would yield a radical new type of astronomy based on non-electromagnetic emissions. We continue our study of a lunar-based system which can provide an important complement to Earth-based analysis because it is completely independent of the geophysical sources of noise on Earth, while providing an Earth-Moon baseline for pin-pointing burst sources in the Universe. We also propose for the first time that a simplified version of the LIGO beam detector optical system, which we will call LLIGO (Lunar LIGO), could be emplaced on the Moon as part of NASA's robotic lander program now under study (Artemis). The Earth-based investigation has two major programs underway. Both involve large interferometer-type gravitational wave antennas.
Gravitational-Wave Cosmology across 29 Decades in Frequency
NASA Astrophysics Data System (ADS)
Lasky, Paul D.; Mingarelli, Chiara M. F.; Smith, Tristan L.; Giblin, John T.; Thrane, Eric; Reardon, Daniel J.; Caldwell, Robert; Bailes, Matthew; Bhat, N. D. Ramesh; Burke-Spolaor, Sarah; Dai, Shi; Dempsey, James; Hobbs, George; Kerr, Matthew; Levin, Yuri; Manchester, Richard N.; Osłowski, Stefan; Ravi, Vikram; Rosado, Pablo A.; Shannon, Ryan M.; Spiewak, Renée; van Straten, Willem; Toomey, Lawrence; Wang, Jingbo; Wen, Linqing; You, Xiaopeng; Zhu, Xingjiang
2016-01-01
Quantum fluctuations of the gravitational field in the early Universe, amplified by inflation, produce a primordial gravitational-wave background across a broad frequency band. We derive constraints on the spectrum of this gravitational radiation, and hence on theories of the early Universe, by combining experiments that cover 29 orders of magnitude in frequency. These include Planck observations of cosmic microwave background temperature and polarization power spectra and lensing, together with baryon acoustic oscillations and big bang nucleosynthesis measurements, as well as new pulsar timing array and ground-based interferometer limits. While individual experiments constrain the gravitational-wave energy density in specific frequency bands, the combination of experiments allows us to constrain cosmological parameters, including the inflationary spectral index nt and the tensor-to-scalar ratio r . Results from individual experiments include the most stringent nanohertz limit of the primordial background to date from the Parkes Pulsar Timing Array, ΩGW(f )<2.3 ×10-10 . Observations of the cosmic microwave background alone limit the gravitational-wave spectral index at 95% confidence to nt≲5 for a tensor-to-scalar ratio of r =0.11 . However, the combination of all the above experiments limits nt<0.36 . Future Advanced LIGO observations are expected to further constrain nt<0.34 by 2020. When cosmic microwave background experiments detect a nonzero r , our results will imply even more stringent constraints on nt and, hence, theories of the early Universe.
Gravitating toward Science: Parent-Child Interactions at a Gravitational-Wave Observatory
ERIC Educational Resources Information Center
Szechter, Lisa E.; Carey, Elizabeth J.
2009-01-01
This research examined the nature of parent-child conversations at an informal science education center housed in an active gravitational-wave observatory. Each of 20 parent-child dyads explored an interactive exhibit hall privately, without the distraction of other visitors. Parents employed a variety of strategies to support their children's…
Gravitational scattering of zero-rest-mass plane waves
NASA Technical Reports Server (NTRS)
De Logi, W. K.; Kovacs, S. J., Jr.
1977-01-01
The Feyman-diagram technique is used to calculate the differential cross sections for the scattering of zero-rest-mass plane waves of spin 0, 1, and 2 by linearized Schwarzschild and Kerr geometries in the long-wavelength weak-field limit. It is found that the polarization of right (or left) circularly polarized electromagnetic waves is unaffected by the scattering process (i.e., helicity is conserved) and that the two helicity (polarization) states of the photon are scattered differently by the Kerr geometry. This coupling between the photon helicity and the angular momentum of the scatterer also leads to a partial polarization of unpolarized incident light. For gravitational waves, on the other hand, there is neither helicity conservation nor helicity-dependent scattering; the angular momentum of the scatterer has no polarizing effect on incident unpolarized gravitational waves.
Black Hole Mergers and Gravitational Waves: Opening the New Frontier
NASA Technical Reports Server (NTRS)
Centrella, Joan
2012-01-01
The final merger of two black holes produces a powerful burst of gravitational waves, emitting more energy than all the stars in the observable universe combined. Since these mergers take place in the regime of strong dynamical gravity, computing the gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For more than 30 years, scientists tried to simulate these mergers using the methods of numerical relativity. The resulting computer codes were plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. In the past several years, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will highlight these breakthroughs and the resulting 'gold rush' of new results that is revealing the dynamics of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.
Black Hole Mergers, Gravitational Waves, and Multi-Messenger Astronomy
NASA Technical Reports Server (NTRS)
Centrella, Joan M.
2010-01-01
The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as the space-based LISA. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. Although numerical codes designed to simulate black hole mergers were plagued for many years by a host of instabilities, recent breakthroughs have conquered these problems and opened up this field dramatically. This talk will focus on the resulting gold rush of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, astrophysics, and testing general relativity.
Nanohertz gravitational wave searches with interferometric pulsar timing experiments.
Tinto, Massimo
2011-05-13
We estimate the sensitivity to nano-Hertz gravitational waves of pulsar timing experiments in which two highly stable millisecond pulsars are tracked simultaneously with two neighboring radio telescopes that are referenced to the same timekeeping subsystem (i.e., "the clock"). By taking the difference of the two time-of-arrival residual data streams we can exactly cancel the clock noise in the combined data set, thereby enhancing the sensitivity to gravitational waves. We estimate that, in the band (10(-9)-10(-8)) Hz, this "interferometric" pulsar timing technique can potentially improve the sensitivity to gravitational radiation by almost 2 orders of magnitude over that of single-telescopes. Interferometric pulsar timing experiments could be performed with neighboring pairs of antennas of the NASA's Deep Space Network and the forthcoming large arraying projects.
Gravitational Wave Signals from Core-Collapse Supernova Explosions
NASA Astrophysics Data System (ADS)
Yakunin, Konstantin; Mezzacappa, Anthony; Frere, Noah; Marronetti, Pedro; Bruenn, Stephen; Hix, W. Raphael; Lentz, Eric J.; Harris, J. Austin; Endeve, Eirik; Messer, O. E. Bronson; Blondin, John
2017-01-01
We present gravitational wave signals produced in two- and three-dimensional simulations of core-collapse supernova explosions. We perform our first-principles simulations with the neutrino hydrodynamics code CHIMERA. The code is based on Newtonian hydrodynamics and MGFLD neutrino transport with realistic neutrino interactions. It includes a nuclear equation of state, general relativistic corrections to the gravitational potential and neutrino transport, and a nuclear reaction network. Our simulations cover a wide range of progenitors from light (9.6M⊙) to heavy (30M⊙) mass. We compute the complete gravitational wave signals for all of these models. In this talk, we present the results and analyze the similarities and differences between the signals.
Gravitational Wave Tests of General Relativity with Future Detectors
NASA Astrophysics Data System (ADS)
Chamberlain, Katie; Yunes, Nicolas
2017-01-01
Gravitational Wave detections with aLIGO have given us unrivalled insight into the extreme gravity regime, in which the gravitational field is strong and dynamical, but where will these types of detections be in 20 years? In this talk, we will explore how the construction of future generations of gravitational wave detectors influences our ability to test General Relativity in extreme gravity. In particular, using the noise spectra for aLIGO, A+, Voyager, CE, and ET-B, as well as the eLISA configurations N2A1, N2A2, and N2A5, we will compare the constraints that eLISA will provide to those that future generations of aLIGO will provide. These studies should produce useful information about instrument design to help guide design of future detectors for tests of gravity. Supported by the Montana Space Grant Consortium.
Space-Based Gravitational-Wave Observatory Mission Concept
NASA Astrophysics Data System (ADS)
Livas, Jeffrey C.
2014-08-01
Space-based Gravitational-wave Observatories (SGOs) will enable the systematic study of the frequency band from 0.0001 - 1 Hz of gravitational waves, where a rich array of astrophysical sources is expected. ESA has selected “The Gravitational Universe” as the science theme for the L3 mission opportunity with a nominal launch date in 2034. This will be at a minimum 15 years after ground-based detectors and pulsar timing arrays announce their first detections and at least 18 years after the LISA Pathfinder Mission will have demonstrated key technologies in a dedicated space mission. It is therefore important to develop mission concepts that can take advantage of the momentum in the field and the investment in both technology development and a precision measurement community on a more near-term timescale than the L3 opportunity. This talk will discuss a mission concept based on the LISA baseline that resulted from a recent mission architecture study.
Theory and experiment in gravitational physics
NASA Technical Reports Server (NTRS)
Will, C. M.
1981-01-01
New technological advances have made it feasible to conduct measurements with precision levels which are suitable for experimental tests of the theory of general relativity. This book has been designed to fill a new need for a complete treatment of techniques for analyzing gravitation theory and experience. The Einstein equivalence principle and the foundations of gravitation theory are considered, taking into account the Dicke framework, basic criteria for the viability of a gravitation theory, experimental tests of the Einstein equivalence principle, Schiff's conjecture, and a model theory devised by Lightman and Lee (1973). Gravitation as a geometric phenomenon is considered along with the parametrized post-Newtonian formalism, the classical tests, tests of the strong equivalence principle, gravitational radiation as a tool for testing relativistic gravity, the binary pulsar, and cosmological tests.
Laser Development for Gravitational-Wave Interferometry in Space
NASA Technical Reports Server (NTRS)
Numata, Kenji; Camp, Jordan
2012-01-01
We are reporting on our development work on laser (master oscillator) and optical amplifier systems for gravitational-wave interferometry in space. Our system is based on the mature, wave-guided optics technologies, which have advantages over bulk, crystal-based, free-space optics. We are investing in a new type of compact, low-noise master oscillator, called the planar-waveguide external cavity diode laser. We made measurements, including those of noise, and performed space-qualification tests.
Accelerated Searches of Gravitational Waves Using Graphics Processing Units
NASA Astrophysics Data System (ADS)
Chung, Shin Kee; Wen, Linqing; Blair, David; Cannon, Kipp
2010-06-01
The existence of gravitational waves was predicted by Albert Einstein. Black hole and neutron star binary systems will product strong gravitational waves through their inspiral and eventual merger. The analysis of the gravitational wave data is computationally intensive, requiring matched filtering of terabytes of data with a bank of at least 3000 numerical templates that represent predicted waveforms. We need to complete the analysis in real-time (within the duration of the signal) in order to enable follow-up observations with some conventional optical or radio telescopes. We report a novel application of a graphics processing units (GPUs) for the purpose of accelerating the search pipelines for gravitational waves from coalescing binary systems of compact objects. A speed-up of 16 fold in total has been achieved with an NVIDIA GeForce 8800 Ultra GPU card compared with a standard central processing unit (CPU). We show that further improvements are possible and discuss the reduction in CPU number required for the detection of inspiral sources afforded by the use of GPUs.
The gravitational wave spectrum from cosmological B-L breaking
Buchmüller, W.; Domcke, V.; Kamada, K.; Schmitz, K. E-mail: valerie.domcke@desy.de E-mail: kai.schmitz@ipmu.jp
2013-10-01
Cosmological B-L breaking is a natural and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase drives hybrid inflation, ending in tachyonic preheating. The decays of heavy B-L Higgs bosons and heavy neutrinos generate entropy, baryon asymmetry and dark matter and also control the reheating temperature. The different phases in the transition from inflation to the radiation dominated phase produce a characteristic spectrum of gravitational waves. We calculate the complete gravitational wave spectrum due to inflation, preheating and cosmic strings, which turns out to have several features. The production of gravitational waves from cosmic strings has large uncertainties, with lower and upper bounds provided by Abelian Higgs strings and Nambu-Goto strings, implying Ω{sub GW}h{sup 2} ∼ 10{sup −13}–10{sup −8}, much larger than the spectral amplitude predicted by inflation. Forthcoming gravitational wave detectors such as eLISA, advanced LIGO, ET, BBO and DECIGO will reach the sensitivity needed to test the predictions from cosmological B-L breaking.
The gravitational wave spectrum from cosmological B-L breaking
NASA Astrophysics Data System (ADS)
Buchmüller, W.; Domcke, V.; Kamada, K.; Schmitz, K.
2013-10-01
Cosmological B-L breaking is a natural and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase drives hybrid inflation, ending in tachyonic preheating. The decays of heavy B-L Higgs bosons and heavy neutrinos generate entropy, baryon asymmetry and dark matter and also control the reheating temperature. The different phases in the transition from inflation to the radiation dominated phase produce a characteristic spectrum of gravitational waves. We calculate the complete gravitational wave spectrum due to inflation, preheating and cosmic strings, which turns out to have several features. The production of gravitational waves from cosmic strings has large uncertainties, with lower and upper bounds provided by Abelian Higgs strings and Nambu-Goto strings, implying ΩGWh2 ~ 10-13-10-8, much larger than the spectral amplitude predicted by inflation. Forthcoming gravitational wave detectors such as eLISA, advanced LIGO, ET, BBO and DECIGO will reach the sensitivity needed to test the predictions from cosmological B-L breaking.
Formation of black hole and emission of gravitational waves.
Nakamura, Takashi
2006-12-01
Numerical simulations were performed for the formation process of rotating black holes. It is suggested that Kerr black holes are formed for wide ranges of initial parameters. The nature of gravitational waves from a test particle falling into a Kerr black hole as well as the development of 3D numerical relativity for the coalescing binary neutron stars are discussed.
Gravitational Wave Detection by Interferometry (Ground and Space).
Pitkin, Matthew; Reid, Stuart; Rowan, Sheila; Hough, Jim
2011-01-01
Significant progress has been made in recent years on the development of gravitational-wave detectors. Sources such as coalescing compact binary systems, neutron stars in low-mass X-ray binaries, stellar collapses and pulsars are all possible candidates for detection. The most promising design of gravitational-wave detector uses test masses a long distance apart and freely suspended as pendulums on Earth or in drag-free spacecraft. The main theme of this review is a discussion of the mechanical and optical principles used in the various long baseline systems in operation around the world - LIGO (USA), Virgo (Italy/France), TAMA300 and LCGT (Japan), and GEO600 (Germany/U.K.) - and in LISA, a proposed space-borne interferometer. A review of recent science runs from the current generation of ground-based detectors will be discussed, in addition to highlighting the astrophysical results gained thus far. Looking to the future, the major upgrades to LIGO (Advanced LIGO), Virgo (Advanced Virgo), LCGT and GEO600 (GEO-HF) will be completed over the coming years, which will create a network of detectors with the significantly improved sensitivity required to detect gravitational waves. Beyond this, the concept and design of possible future "third generation" gravitational-wave detectors, such as the Einstein Telescope (ET), will be discussed.
Formation of black hole and emission of gravitational waves
Nakamura, Takashi
2006-01-01
Numerical simulations were performed for the formation process of rotating black holes. It is suggested that Kerr black holes are formed for wide ranges of initial parameters. The nature of gravitational waves from a test particle falling into a Kerr black hole as well as the development of 3D numerical relativity for the coalescing binary neutron stars are discussed. PMID:25792793
Gravitational damping of Alfven waves in stellar atmospheres and winds
NASA Technical Reports Server (NTRS)
Khabibrakhmanov, I. K.; Mullan, D. J.
1994-01-01
We consider how gravity affects the propagation of Alfven waves in a stellar atmosphere. We show that when the ion gyrofrequency exceeds the collision rate, the waves are absorbed at a rate proportional to the gravitational acceleration g. Estimates show that this mechanism can readily account for the observed energy losses in the solar chromosphere. The mechanism predicts that the pressure at the top of the chromosphere P(sub Tc) should scale with g as P(sub Tc) proportional to g(exp delta), where delta approximately equals 2/3; this is close to empirical results which suggest delta approximately equals 0.6. Gravitational damping leads to deposition of energy at a rate proportional to the mass of the particles. Hence, heavier ion are heated more effectively than protons. This is consistent with the observed proportionality between ion temperature and mass in the solar wind. Gravitational damping causes the local g to be effectively decreased by an amount proportional to the wave energy. This feature affects the acceleration of the solar wind. Gravitational damping may also lead to self-regulation of the damping of Alfven waves in stellar winds: this is relevant in the context of slow massive winds in cool giants.
Chiral primordial gravitational waves from dilaton induced delayed chromonatural inflation
NASA Astrophysics Data System (ADS)
Obata, Ippei; Soda, Jiro; CLEO Collaboration
2016-06-01
We study inflation driven by a dilaton and an axion, both of which are coupled to a SU(2) gauge field. We find that the inflation driven by the dilaton occurs in the early stage of inflation during which the gauge field grows due to the gauge-kinetic function. When the energy density of magnetic fields catches up with that of electric fields, chromonatural inflation takes over in the late stage of inflation, which we call delayed chromonatural inflation. Thus, the delayed chromonatural inflation driven by the axion and the gauge field is induced by the dilaton. The interesting outcome of the model is the generation of chiral primordial gravitational waves on small scales. Since the gauge field is inert in the early stage of inflation, it is viable in contrast to the conventional chromonatural inflation. We find the parameter region where chiral gravitational waves are generated in a frequency range higher than nHz, which are potentially detectable in future gravitational wave interferometers and pulsar-timing arrays such as DECi-hertz Interferometer Gravitational wave Observatory (DECIGO), evolved Laser Interferometer Space Antenna (eLISA), and Square Kilometer Array (SKA).
Signal photon flux generated by high-frequency relic gravitational waves
NASA Astrophysics Data System (ADS)
Li, Xin; Wang, Sai; Wen, Hao
2016-08-01
The power spectrum of primordial tensor perturbations increases rapidly in the high frequency region if the spectral index n t > 0. It is shown that the amplitude of relic gravitational waves h t(5 × 109 Hz) varies from 10-36 to 10-25 while n t varies from -6.25 × 10-3 to 0.87. A high frequency gravitational wave detector proposed by F.-Y. Li detects gravitational waves through observing the perturbed photon flux that is generated by interaction between relic gravitational waves and electromagnetic field. It is shown that the perturbative photon flux (5 × 109 Hz) varies from 1.40 × 10-4 s-1 to 2.85 × 107 s-1 while n t varies from -6.25 × 10-3 to 0.87. Correspondingly, the ratio of the transverse perturbative photon flux to the background photon flux varies from 10-28 to 10-16. Supported by National Natural Science Foundation of China (11305181,11322545,11335012) and Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Y5KF181CJ1)
Binary Black Hole Late Inspiral: Simulations for Gravitational Wave Observations
NASA Technical Reports Server (NTRS)
Baker, John G.; vanMeter, James R.; Centrella, Joan; Choi, Dae-Il; Kelly, Bernard J.; Koppitz, Michael
2006-01-01
Coalescing binary black hole mergers are expected to be the strongest gravitational wave sources for ground-based interferometers, such as the LIGO, VIRGO, and GEO600, as well as the spacebased interferometer LISA. Until recently it has been impossible to reliably derive the predictions of General Relativity for the final merger stage, which takes place in the strong-field regime. Recent progress in numerical relativity simulations is, however, revolutionizing our understanding of these systems. We examine here the specific case of merging equal-mass Schwarzschild black holes in detail, presenting new simulations in which the black holes start in the late inspiral stage on orbits with very low eccentricity and evolve for approximately 1200M through approximately 7 orbits before merging. We study the accuracy and consistency of our simulations and the resulting gravitational waveforms, which encompass approximately 14 cycles before merger, and highlight the importance of using frequency (rather than time) to set the physical reference when comparing models. Matching our results to PN calculations for the earlier parts of the inspiral provides a combined waveform with less than half a cycle of accumulated phase error through the entire coalescence. Using this waveform, we calculate signal-to-noise ratios (SNRs) for iLIGO, adLIGO, and LISA, highlighting the contributions from the late-inspiral and merger-ringdown parts of the waveform which can now be simulated numerically. Contour plots of SNR as a function of z and M show that adLIGO can achieve SNR 2 10 for some IMBBHs out to z approximately equals 1, and that LISA can see MBBHs in the range 3 x 10(exp 4) approximately < M/Mo approximately < 10(exp 7) at SNR > 100 out to the earliest epochs of structure formation at z > 15.
Lunar Laser Ranging: A Playground for Gravitational Physics
NASA Astrophysics Data System (ADS)
Murphy, Tom
2013-04-01
Laser ranging to the reflectors placed on the Moon by the Apollo astronauts has long been a productive tool for probing gravitation, continuing to this day. This talk will survey the gravitational physics tested by lunar ranging and prospects for the future, touching on contributions to the endeavor by Irwin Shapiro, in celebration of the Einstein Prize.
Towards robust gravitational wave detection with pulsar timing arrays
NASA Astrophysics Data System (ADS)
Cornish, Neil J.; Sampson, Laura
2016-05-01
Precision timing of highly stable millisecond pulsars is a promising technique for the detection of very low frequency sources of gravitational waves. In any single pulsar, a stochastic gravitational wave signal appears as an additional source of timing noise that can be absorbed by the noise model, and so it is only by considering the coherent response across a network of pulsars that the signal can be distinguished from other sources of noise. In the limit where there are many gravitational wave sources in the sky, or many pulsars in the array, the signals produce a unique tensor correlation pattern that depends only on the angular separation between each pulsar pair. It is this distinct fingerprint that is used to search for gravitational waves using pulsar timing arrays. Here we consider how the prospects for detection are diminished when the statistical isotropy of the timing array or the gravitational wave signal is broken by having a finite number of pulsars and a finite number of sources. We find the standard tensor-correlation analysis to be remarkably robust, with a mild impact on detectability compared to the isotropic limit. Only when there are very few sources and very few pulsars does the standard analysis begin to fail. Having established that the tensor correlations are a robust signature for detection, we study the use of "sky scrambles" to break the correlations as a way to increase confidence in a detection. This approach is analogous to the use of "time slides" in the analysis of data from ground-based interferometric detectors.
Gamma-ray-burst beaming and gravitational-wave observations.
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.
LIGO GW150914 and GW151226 gravitational wave detection and generalized gravitation theory (MOG)
NASA Astrophysics Data System (ADS)
Moffat, J. W.
2016-12-01
The nature of gravitational waves in a generalized gravitation theory is investigated. The linearized field equations and the metric tensor quadrupole moment power and the decrease in radius of an inspiralling binary system of two compact objects are derived. The generalized Kerr metric describing a spinning black hole is determined by its mass M and the spin parameter a = cS / GM2. The LIGO-Virgo collaboration data is fitted with smaller binary black hole masses in agreement with the current electromagnetic, observed X-ray binary upper bound for a black hole mass, M ≲ 10M⊙.
Gravitational collapse of dissipative fluid as a source of gravitational waves
Chakraborty, Sanjukta Chakraborty, Subenoy
2016-01-15
Gravitational collapse of cylindrical anisotropic fluid has been considered in analogy with the work of Misner and Sharp. Using Darmois matching conditions, the interior cylindrical dissipative fluid (in the form of shear viscosity and heat flux) is matched to an exterior vacuum Einstein–Rosen space–time. It is found that on the bounding 3-surface the radial pressure of the anisotropic perfect fluid is linearly related to the shear viscosity and the heat flux of the dissipative fluid on the boundary. This non-zero radial pressure on the bounding surface may be considered as the source of gravitational waves outside the collapsing matter distribution.
Broadband searches for continuous gravitational waves
NASA Astrophysics Data System (ADS)
Dergachev, Vladimir; LIGO/Virgo Collaboration Collaboration
2017-01-01
Isolated rotating neutron stars are expected to emit gravitational radiation of nearly constant frequency and amplitude. Searches for such radiation from unknown stars are computationally limited, with all-sky searches of initial LIGO and Virgo data achieving sensitivity to strains smaller than 10-24. Because CW amplitudes are thought to be extremely weak, long time integrations must be carried out to detect a signal. Integration is complicated by the motion of the Earth (daily rotation and orbital motion) which induces substantial modulations of detected frequency and amplitude that are highly dependent on source location. Large volumes of acquired data make this search computationally difficult. We will present recently published results and discuss algorithms used to analyze large volumes of data.
Massive gravitational waves in Chern-Simons modified gravity
Myung, Yun Soo; Moon, Taeyoon E-mail: tymoon@inje.ac.kr
2014-10-01
We consider the nondynamical Chern-Simons (nCS) modified gravity, which is regarded as a parity-odd theory of massive gravity in four dimensions. We first find polarization modes of gravitational waves for θ=x/μ in nCS modified gravity by using the Newman-Penrose formalism where the null complex tetrad is necessary to specify gravitational waves. We show that in the Newman–Penrose formalism, the number of polarization modes is one in addition to an unspecified Ψ{sub 4}, implying three degrees of freedom for θ=x/μ. This compares with two for a canonical embedding of θ=t/μ. Also, if one introduces the Ricci tensor formalism to describe a massive graviton arising from the nCS modified gravity, one finds one massive mode after making second-order wave equations, which is compared to five found from the parity-even Einstein–Weyl gravity.
Gravitational wave memory: A new approach to study modified gravity
NASA Astrophysics Data System (ADS)
Du, Song Ming; Nishizawa, Atsushi
2016-11-01
It is well known that two types of gravitational wave memory exist in general relativity (GR): the linear memory and the nonlinear, or Christodoulou, memory. These effects, especially the latter, depend on the specific form of the Einstein equation. It can then be speculated that, in modified theories of gravity, the memory can differ from the GR prediction and provides novel phenomena to study these theories. We support this speculation by considering scalar-tensor theories, for which we find two new types of memory: the T memory and the S memory, which contribute to the tensor and scalar components of a gravitational wave, respectively. Specifically, the former is caused by the burst of energy carried away by scalar radiation, while the latter is intimately related to the no scalar hair property of black holes in scalar-tensor gravity. We estimate the size of these two types of memory in gravitational collapses and formulate a detection strategy for the S memory, which can be singled out from tensor gravitational waves. We show that (i) the S memory exists even in spherical symmetry and is observable under current model constraints, and (ii) while the T memory is usually much weaker than the S memory, it can become comparable in the case of spontaneous scalarization.
Quantum Measurement Theory in Gravitational-Wave Detectors
NASA Astrophysics Data System (ADS)
Danilishin, Stefan L.; Khalili, Farid Ya.
2012-12-01
The fast progress in improving the sensitivity of the gravitational-wave detectors, we all have witnessed in the recent years, has propelled the scientific community to the point at which quantum behavior of such immense measurement devices as kilometer-long interferometers starts to matter. The time when their sensitivity will be mainly limited by the quantum noise of light is around the corner, and finding ways to reduce it will become a necessity. Therefore, the primary goal we pursued in this review was to familiarize a broad spectrum of readers with the theory of quantum measurements in the very form it finds application in the area of gravitational-wave detection. We focus on how quantum noise arises in gravitational-wave interferometers and what limitations it imposes on the achievable sensitivity. We start from the very basic concepts and gradually advance to the general linear quantum measurement theory and its application to the calculation of quantum noise in the contemporary and planned interferometric detectors of gravitational radiation of the first and second generation. Special attention is paid to the concept of the Standard Quantum Limit and the methods of its surmounting.
Rapid Radio Followups of LIGO Gravitational Wave Events
NASA Astrophysics Data System (ADS)
Jenet, Rick; Stevens, Jamie; Wieringa, Mark; Creighton, Teviet
2010-10-01
We propose real time follow-up observations with the ATCA to search for radio counterparts to candidate gravitational-wave events detected by the LIGO and Virgo detectors. Electromagnetic and gravitational radiation provide complementary views of the Universe: the former being generated by the microphysical processes of charged particles, the latter by coherent bulk motion of masses. A complete picture of the most violent events in nature, such as supernovae and mergers of stellar remnants, will require both types of observation: Gravitational waves (GWs) to uncover the mechanics of the underlying (gravitational) energy source, and electromagnetic waves to reveal how that energy is then dissipated in matter. The search for GWs is entering an exciting phase with kilometer-scale interferometric detectors LIGO and Virgo achieving sensitivities for which detection of GWs is plausible. Since the sensitivity of these instruments improves incrementally, it is likely that the first verifiable detections of GWs will have signal-to-noise ratios that are just barely statistically significant. Observations in the electromagnetic spectrum will help confirm the first GW detections.
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
This viewgraph presentation reviews the massive black hole (MBH) binaries that are found at the center of most galaxies, "astronomical messenger", gravitational waves (GW), and the use of numerical relativity understand the features of these phenomena. The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity.. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Quantum Measurement Theory in Gravitational-Wave Detectors.
Danilishin, Stefan L; Khalili, Farid Ya
2012-01-01
The fast progress in improving the sensitivity of the gravitational-wave detectors, we all have witnessed in the recent years, has propelled the scientific community to the point at which quantum behavior of such immense measurement devices as kilometer-long interferometers starts to matter. The time when their sensitivity will be mainly limited by the quantum noise of light is around the corner, and finding ways to reduce it will become a necessity. Therefore, the primary goal we pursued in this review was to familiarize a broad spectrum of readers with the theory of quantum measurements in the very form it finds application in the area of gravitational-wave detection. We focus on how quantum noise arises in gravitational-wave interferometers and what limitations it imposes on the achievable sensitivity. We start from the very basic concepts and gradually advance to the general linear quantum measurement theory and its application to the calculation of quantum noise in the contemporary and planned interferometric detectors of gravitational radiation of the first and second generation. Special attention is paid to the concept of the Standard Quantum Limit and the methods of its surmounting.
NANOGrav Constraints on Gravitational Wave Bursts with Memory
NASA Astrophysics Data System (ADS)
Arzoumanian, Z.; Brazier, A.; Burke-Spolaor, S.; Chamberlin, S. J.; Chatterjee, S.; Christy, B.; Cordes, J. M.; Cornish, N. J.; Demorest, P. B.; Deng, X.; Dolch, T.; Ellis, J. A.; Ferdman, R. D.; Fonseca, E.; Garver-Daniels, N.; Jenet, F.; Jones, G.; Kaspi, V. M.; Koop, M.; Lam, M. T.; Lazio, T. J. W.; Levin, L.; Lommen, A. N.; Lorimer, D. R.; Luo, J.; Lynch, R. S.; Madison, D. R.; McLaughlin, M. A.; McWilliams, S. T.; Nice, D. J.; Palliyaguru, N.; Pennucci, T. T.; Ransom, S. M.; Siemens, X.; Stairs, I. H.; Stinebring, D. R.; Stovall, K.; Swiggum, J.; Vallisneri, M.; van Haasteren, R.; Wang, Y.; Zhu, W. W.; NANOGrav Collaboration
2015-09-01
Among efforts to detect gravitational radiation, pulsar timing arrays are uniquely poised to detect “memory” signatures, permanent perturbations in spacetime from highly energetic astrophysical events such as mergers of supermassive black hole binaries. The North American Nanohertz Observatory for Gravitational Waves (NANOGrav) observes dozens of the most stable millisecond pulsars using the Arecibo and Green Bank radio telescopes in an effort to study, among other things, gravitational wave memory. We herein present the results of a search for gravitational wave bursts with memory (BWMs) using the first five years of NANOGrav observations. We develop original methods for dramatically speeding up searches for BWM signals. In the directions of the sky where our sensitivity to BWMs is best, we would detect mergers of binaries with reduced masses of {10}9 {M}⊙ out to distances of 30 Mpc; such massive mergers in the Virgo cluster would be marginally detectable. We find no evidence for BWMs. However, with our non-detection, we set upper limits on the rate at which BWMs of various amplitudes could have occurred during the time spanned by our data—e.g., BWMs with amplitudes greater than 10-13 must encounter the Earth at a rate less than 1.5 yr-1.
Chirality oscillation of primordial gravitational waves during inflation
NASA Astrophysics Data System (ADS)
Cai, Yong; Wang, Yu-Tong; Piao, Yun-Song
2017-03-01
We show that if the gravitational Chern-Simons term couples to a massive scalar field ( m > H), the primordial gravitational waves (GWs) will show itself the chirality oscillation, i.e., the amplitudes of the left- and right-handed GWs modes will convert into each other and oscillate in their propagations. This oscillation will eventually develop a permanent difference of the amplitudes of both modes, which leads to nearly opposite oscillating shapes in the power spectra of the left- and right-handed primordial GWs. We discuss its implication to the CMB B-mode polarization.
NASA's Preparations for ESA's L3 Gravitational Wave Mission
NASA Astrophysics Data System (ADS)
Stebbins, Robin T.
2016-01-01
In November 2013, the European Space Agency (ESA) selected the science theme, the "Gravitational Universe," for its third large mission opportunity, known as 'L3,' under its Cosmic Vision Programme. The planned launch date is 2034. NASA is seeking a role as an international partner in L3. NASA is supporting: (1) US participation in early mission studies, (2) US technology development, (3) pre-decadal preparations, (4) ESA's LISA Pathfinder mission and (5) the ST7 Disturbance Reduction System project. This talk summarizes NASA's preparations for a future gravitational-wave mission.
Precision Laser Development for Gravitational Wave Space Mission
NASA Technical Reports Server (NTRS)
Numata, Kenji; Camp, Jordan
2011-01-01
Optical fiber and semiconductor laser technologies have evolved dramatically over the last decade due to the increased demands from optical communications. We are developing a laser (master oscillator) and optical amplifier based on those technologies for interferometric space missions, such as the gravitational-wave mission LISA, and GRACE follow-on, by fully utilizing the mature wave-guided optics technologies. In space, where a simple and reliable system is preferred, the wave-guided components are advantageous over bulk, crystal-based, free-space laser, such as NPRO (Non-planar Ring Oscillator) and bulk-crystal amplifier, which are widely used for sensitive laser applications on the ground.
ERIC Educational Resources Information Center
Fuller, Robert G., Ed.; And Others
This is part of a series of 42 Calculus Based Physics (CBP) modules totaling about 1,000 pages. The modules include study guides, practice tests, and mastery tests for a full-year individualized course in calculus-based physics based on the Personalized System of Instruction (PSI). The units are not intended to be used without outside materials;…
Tests of general relativity from gravitational wave observations of binary black holes
NASA Astrophysics Data System (ADS)
Del Pozzo, Walter
2017-01-01
Gravitational waves emitted during the coalescence of compact binary systems carry a wealth of information about the merging objects, the remnant object as well as their interaction with space-time. The description of the dynamics of such systems is based on solutions of the theory of general relativity. For any given physical configuration of masses, spins and orbital motion, general relativity predicts the dynamical evolution of the binary system as well as the corresponding gravitational wave signal. During the coalescence of extremely compact objects such as binary black holes, the typical curvature and velocity at play are such that, from the observation of the gravitational wave signal, we can access the most extreme dynamical regimes of gravity. In such conditions, we can test our understanding of gravity by looking for potential departures between the solutions of general relativity and the actual dynamics of space-time. The LIGO observations GW150914 and GW151226 provided wonderful testing grounds for general relativity in the, up to now unaccessible, strong-field dynamical regime of gravity. During my talk, I will review and discuss several of the tests that have been devised to detect violations of the predictions of general relativity from the observation of gravitational waves from coalescing binary systems. The discussion will be based on the results of the analysis of GW150914 and GW151226. Finally, I will conclude by discussing some of the future prospects of extending the current state-of-the-art methodologies to further aspects of general relativity.
Cryogenically cooled ultra low vibration silicon mirrors for gravitational wave observatories
NASA Astrophysics Data System (ADS)
Shapiro, Brett; Adhikari, Rana X.; Aguiar, Odylio; Bonilla, Edgard; Fan, Danyang; Gan, Litawn; Gomez, Ian; Khandelwal, Sanditi; Lantz, Brian; MacDonald, Tim; Madden-Fong, Dakota
2017-01-01
Interferometric gravitational wave observatories recently launched a new field of gravitational wave astronomy with the first detections of gravitational waves in 2015. The number and quality of these detections is limited in part by thermally induced vibrations in the mirrors, which show up as noise in these interferometers. One way to reduce this thermally induced noise is to use low temperature mirrors made of high purity single-crystalline silicon. However, these low temperatures must be achieved without increasing the mechanical vibration of the mirror surface or the vibration of any surface within close proximity to the mirrors. The vibration of either surface can impose a noise inducing phase shift on the light within the interferometer or physically push the mirror through oscillating radiation pressure. This paper proposes a system for the Laser Interferometric Gravitational-wave Observatory (LIGO) to achieve the dual goals of low temperature and low vibration to reduce the thermally induced noise in silicon mirrors. Experimental results are obtained at Stanford University to prove that these dual goals can be realized simultaneously.
Scale-dependent gravitational waves from a rolling axion
Namba, Ryo; Shiraishi, Maresuke; Peloso, Marco; Unal, Caner; Sorbo, Lorenzo E-mail: peloso@physics.umn.edu E-mail: sorbo@physics.umass.edu
2016-01-01
We consider a model in which a pseudo-scalar field σ rolls for some e-folds during inflation, sourcing one helicity of a gauge field. These fields are only gravitationally coupled to the inflaton, and therefore produce scalar and tensor primordial perturbations only through gravitational interactions. These sourced signals are localized on modes that exit the horizon while the roll of σ is significant. We focus our study on cases in which the model can simultaneously produce (i) a large gravitational wave signal, resulting in observable B-modes of the CMB polarizations, and (ii) sufficiently small scalar perturbations, so to be in agreement with the current limits from temperature anisotropies. Different choices of parameters can instead lead to a localized and visible departure from gaussianity in the scalar sector, either at CMB or LSS scales.
Binary black holes, gravitational waves, and numerical relativity
NASA Astrophysics Data System (ADS)
Centrella, Joan M.; Baker, John G.; Boggs, William D.; Kelly, Bernard J.; McWilliams, Sean T.; van Meter, James R.
2007-07-01
The final merger of comparable mass binary black holes produces an intense burst of gravitational radiation and is one of the strongest sources for both ground-based and space-based gravitational wave detectors. Since the merger occurs in the strong-field dynamical regime of general relativity, numerical relativity simulations of the full Einstein equations in 3-D are required to calculate the resulting gravitational dynamics and waveforms. While this problem has been pursued for more than 30 years, the numerical codes have long been plagued by various instabilities and, overall, progress was incremental. Recently, however, dramatic breakthrough have occurred, resulting in robust simulations of merging black holes. In this paper, we examine these developments and the exciting new results that are emerging.
Probing the internal composition of neutron stars with gravitational waves
NASA Astrophysics Data System (ADS)
Chatziioannou, Katerina; Yagi, Kent; Klein, Antoine; Cornish, Neil; Yunes, Nicolás
2015-11-01
Gravitational waves from neutron star binary inspirals contain information about the as yet unknown equation of state of supranuclear matter. In the absence of definitive experimental evidence that determines the correct equation of state, a number of diverse models that give the pressure inside a neutron star as function of its density have been constructed by nuclear physicists. These models differ not only in the approximations and techniques they employ to solve the many-body Schrödinger equation, but also in the internal neutron star composition they assume. We study whether gravitational wave observations of neutron star binaries in quasicircular inspirals up to contact will allow us to distinguish between equations of state of differing internal composition, thereby providing important information about the properties and behavior of extremely high density matter. We carry out a Bayesian model selection analysis, and find that second generation gravitational wave detectors can heavily constrain equations of state that contain only quark matter, but hybrid stars containing both normal and quark matter are typically harder to distinguish from normal matter stars. A gravitational wave detection with a signal-to-noise ratio of 20 and masses around 1.4 M⊙ would provide indications of the existence or absence of strange quark stars, while a signal-to-noise ratio 30 detection could either detect or rule out strange quark stars with a 20 to 1 confidence. The presence of kaon condensates or hyperons in neutron star inner cores cannot be easily confirmed. For example, for the equations of state studied in this paper, even a gravitational wave signal with a signal-to-noise ratio as high as 60 would not allow us to claim a detection of kaon condensates or hyperons with confidence greater than 5 to 1. On the other hand, if kaon condensates and hyperons do not form in neutron stars, a gravitational wave signal with similar signal-to-noise ratio would be able to
On propagation of electromagnetic and gravitational waves in the expanding Universe
NASA Astrophysics Data System (ADS)
Gladyshev, V. O.
2016-07-01
The purpose of this study was to obtain an equation for the propagation time of electromagnetic and gravitational waves in the expanding Universe. The velocity of electromagnetic waves propagation depends on the velocity of the interstellar medium in the observer's frame of reference. Gravitational radiation interacts weakly with the substance, so electromagnetic and gravitational waves propagate from a remote astrophysical object to the terrestrial observer at different time. Gravitational waves registration enables the inverse problem solution - by the difference in arrival time of electromagnetic and gravitational-wave signal, we can determine the characteristics of the emitting area of the astrophysical object.
Gravitational Wave Signatures in Black Hole Forming Core Collapse
NASA Astrophysics Data System (ADS)
Cerdá-Durán, Pablo; DeBrye, Nicolas; Aloy, Miguel A.; Font, José A.; Obergaulinger, Martin
2013-12-01
We present general relativistic numerical simulations of collapsing stellar cores. Our initial model consists of a low metallicity rapidly-rotating progenitor which is evolved in axisymmetry with the latest version of our general relativistic code CoCoNuT, which allows for black hole formation and includes the effects of a microphysical equation of state (LS220) and a neutrino leakage scheme to account for radiative losses. The motivation of our study is to analyze in detail the emission of gravitational waves in the collapsar scenario of long gamma-ray bursts. Our simulations show that the phase during which the proto-neutron star (PNS) survives before ultimately collapsing to a black hole is particularly optimal for gravitational wave emission. The high-amplitude waves last for several seconds and show a remarkable quasi-periodicity associated with the violent PNS dynamics, namely during the episodes of convection and the subsequent nonlinear development of the standing-accretion shock instability (SASI). By analyzing the spectrogram of our simulations we are able to identify the frequencies associated with the presence of g-modes and with the SASI motions at the PNS surface. We note that the gravitational waves emitted reach large enough amplitudes to be detected with third-generation detectors such as the Einstein Telescope within a Virgo Cluster volume at rates <~ 0.1 yr-1.
GRAVITATIONAL WAVE SIGNATURES IN BLACK HOLE FORMING CORE COLLAPSE
Cerdá-Durán, Pablo; DeBrye, Nicolas; Aloy, Miguel A.; Font, José A.; Obergaulinger, Martin
2013-12-20
We present general relativistic numerical simulations of collapsing stellar cores. Our initial model consists of a low metallicity rapidly-rotating progenitor which is evolved in axisymmetry with the latest version of our general relativistic code CoCoNuT, which allows for black hole formation and includes the effects of a microphysical equation of state (LS220) and a neutrino leakage scheme to account for radiative losses. The motivation of our study is to analyze in detail the emission of gravitational waves in the collapsar scenario of long gamma-ray bursts. Our simulations show that the phase during which the proto-neutron star (PNS) survives before ultimately collapsing to a black hole is particularly optimal for gravitational wave emission. The high-amplitude waves last for several seconds and show a remarkable quasi-periodicity associated with the violent PNS dynamics, namely during the episodes of convection and the subsequent nonlinear development of the standing-accretion shock instability (SASI). By analyzing the spectrogram of our simulations we are able to identify the frequencies associated with the presence of g-modes and with the SASI motions at the PNS surface. We note that the gravitational waves emitted reach large enough amplitudes to be detected with third-generation detectors such as the Einstein Telescope within a Virgo Cluster volume at rates ≲ 0.1 yr{sup –1}.
The Peoples Republic of China High-Frequency Gravitational Wave Research Program
NASA Astrophysics Data System (ADS)
Baker, Robert M. L.
2009-03-01
For the past decade the Peoples Republic of China has been increasingly active in the pursuit of High-Frequency Gravitational Wave (HFGW) research. Much of their progress has been during 2008. An epochal achievement was the publication of the theoretical analysis of the Li-Baker HFGW detector in the European Physical Journal C (Li, et al., 2008), "Perturbative Photon Fluxes Generated by High-Frequency Gravitational Waves and Their Physical Effects"). Many Chinese scientists and graduate students have participated in these HFGW studies and their contributions are briefly discussed. Some of the key scientists and their institutions are as follows: first from Chongqing University: Zhenyun Fang, Director of the Institute of Theoretical Physics, Xing gang Wu, The Institute of Theoretical Physics, Nan Yang, The Institute of Gravitational Physics; Jun Luo, Huazhong University of Science and Technology (HUST), Wuhan, China, the Head of Gravitational Laboratory, Yang Zhang, University of Science and Technology of China, Associate Dean of the College of Sciences, Biao Li, Institute of Electronic Engineering of China Academy of Engineering Physics (CAEP), Chief of Microwave Antenna Division, Chuan-Ming Zhou, Technology Committee of Institute of Electronic Engineering of the CAEP, Jie Zhou, Institute of Electronic Engineering of the CAEP, Chief of the Signal Processing Division; Weijia Wen, Department of Physics, The Hong Kong University of Science and Technology. This Chinese HFGW team includes two parts: (1) Theoretical study and (2) Experimental investigation. These two parts have closed relations, and many cross projects, including cooperation between the American GravWave and Chinese HFGW teams. Referring to financial support, The Institute of Electronic Engineering (i.e., Microwave Laboratory) has already (June 2008) provided support more than three million Yuan for the HFGW detection project and this activity is discussed.
Predicting Electromagnetic Signatures of Gravitational Wave Sources
NASA Astrophysics Data System (ADS)
D'Orazio, Daniel John
This dissertation investigates the signatures of electromagnetic radiation that may accompany two specific sources of gravitational radiation: the inspiral and merger of massive black hole binaries (MBHBs) in galactic nuclei, and the coalescence of black hole neutron star (BHNS) pairs. Part I considers the interaction of MBHBs, at sub-pc separations, with a circumbinary gas disk. Accretion rates onto the MBHB are calculated from two-dimensional hydrodynamical simulations as a function of the relative masses of the black holes. The results are applied to interpretation of the recent, sub-pc separation MBHB candidate in the nucleus of the periodically variable Quasar PG 1302-102. We advance an interpretation of the variability observed in PG 1302-102 as being caused by Doppler-boosted emission sourced by the orbital velocity of the smaller black hole in a MBHB with disparate relative masses. Part II considers BHNS binaries in which the black hole is large enough to swallow the neutron star whole before it is disrupted. As the pair nears merger, orbital motion of the black hole through the magnetosphere of the neutron star generates an electromotive force, a black-hole-battery, which, for the strongest neutron star magnetic field strengths, could power luminosities large enough to make the merging pair observable out to cosmic distances. Relativistic solutions for vacuum fields of a magnetic dipole near a horizon are given, and a mechanism for harnessing the power of the black-hole-battery is put forth in the form of a fireball emitting in hard X-rays to gamma-rays.
LISA and LISA Pathfinder: Gravitational Wave Observation in Space
NASA Technical Reports Server (NTRS)
Guzman, Felipe
2010-01-01
The Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA gravitational wave observatory in the frequency range of 0.1 mHz--100 mHz. This observation band is inaccessible to ground-based detectors due to fluctuations in the Earth gravitational field. Gravitational wave sources for LISA include galactic binaries, mergers of supermassive black-hole binaries, extreme-mass-ratio inspirals, and cosmology backgrounds and bursts. LISA is a constellation of three spacecraft separated by 5 million km in an equilateral triangle, whose center follows the Earth in a heliocentric orbit with an orbital phase offset of 20 degrees. Challenging technology is required to ensure pure geodetic trajectories of the six onboard test masses, whose distance fluctuations will be measured by interspacecraft laser interferometers with picometer accuracy. LISA Pathfinder is an ESA-launched technology demonstration mission of key LISA subsystems such as spacecraft control with micronewton thrusters, test mass drag-free control, and precision laser interferometry between free-flying test masses. Ground testing of hardware of the Gravitational Reference Sensor and Optical Metrology subsystems of LISA Pathfinder is currently ongoing. A detailed description of the two missions and an overview of current investigations conducted by the community will be discussed. The current status in development and implementation of LISA Pathfinder pre-flight systems and latest results of the ongoing ground testing efforts will also be presented.
Sonic search for monopoles, gravitational waves and newtorites
NASA Astrophysics Data System (ADS)
Bernard, C.; de Rújula, A.; Lautrup, B.
1984-08-01
Hopes for the detection of gravitational waves and of very massive magnetic monopoles rely on cosmological sources - the big bang itself in the monopole's case. Some gravitational wave antennas are ``acoustic'' resonant detectors, that have reached a sensitivity not far from the ``quantum limit''. We investigate in detail the response of these sensitive detectors to the passage of ``relic'' monopoles. We compute signal to noise ratios for a variety of target materials, and we find them to be favourable for the very cold, high quality resonators that are presently contemplated. A monopole traversing a metal produces a ``thermo-acoustic'' pulse, whose amplitude is linear in the monopole's velocity, β. If the metal is superconducting, there is a novel additional ``magneto-acoustic'' source, whose amplitude is β-independent. Monopole detectors that rely on ionization have a sensitivity threshold in β, and may conceivably be blind to relic monopoles. The response of superconducting loop detectors is β-independent, but their collection areas are limited by the requirement of a sophisticated magnetic shielding. Neither of the above limitations would be shared by an acoustic monopole detector. We sketch a ``sonic antenna'' that would respond directionally to coventional cosmic rays, gravitational radiation, monopoles, and even to more exotic signals, like newtorites (elementary or composite ``meteorites'' that interact with ordinary matter only gravitationally). Permanent address: Niels Bohr Institute, Blegdamsvej 17, Copenhagen Ø, Denmark.
Searching for gamma-ray counterpart of gravitational wave transients
NASA Astrophysics Data System (ADS)
Sol, H.
2016-12-01
With the recent direct detection of gravitational waves (GW), the search for electromagnetic counterpart of gravitational transients appears as a new challenge for astronomers. Information provided by electromagnetic data is complementary to the one deduced from the gravitational signal. Detecting the same event through the two messengers would be highly interesting to better identify the sources and refine their parameters. The scarcity of cosmic sources detected at very high energy (VHE) suggests that the gamma-ray domain could be useful to catch first electromagnetic signatures and reduce error boxes. Present IACT (Imaging Atmospheric Cherenkov Telescopes) like the High Energy Stereoscopic System (H.E.S.S.) operating in Namibia, 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 are already participating in the electromagnetic follow up of LIGO-Virgo gravitational wave event candidates. In the next decade the Cherenkov Telescope Array (CTA), operating with a larger field of view, a higher sensitivity in the VHE gamma-ray range between 20 GeV and 300 TeV, and a fast re-positionning, will be perfectly adapted to this observational program.
Collett, Thomas E; Bacon, David
2017-03-03
Probing the relative speeds of gravitational waves and light acts as an important test of general relativity and alternative theories of gravity. Measuring the arrival time of gravitational waves (GWs) and electromagnetic (EM) counterparts can be used to measure the relative speeds, but only if the intrinsic time lag between emission of the photons and gravitational waves is well understood. Here we suggest a method that does not make such an assumption, using future strongly lensed GW events and EM counterparts; Biesiada et al. [J. Cosmol. Astropart. Phys.10 (2014) 080JCAPBP1475-751610.1088/1475-7516/2014/10/080] forecast that 50-100 strongly lensed GW events will be observed each year with the Einstein Telescope. A single strongly lensed GW event would produce robust constraints on c_{GW}/c_{γ} at the 10^{-7} level, if a high-energy EM counterpart is observed within the field of view of an observing γ-ray burst monitor.
TianQin: a space-borne gravitational wave detector
NASA Astrophysics Data System (ADS)
Luo, Jun; Chen, Li-Sheng; Duan, Hui-Zong; Gong, Yun-Gui; Hu, Shoucun; Ji, Jianghui; Liu, Qi; Mei, Jianwei; Milyukov, Vadim; Sazhin, Mikhail; Shao, Cheng-Gang; Toth, Viktor T.; Tu, Hai-Bo; Wang, Yamin; Wang, Yan; Yeh, Hsien-Chi; Zhan, Ming-Sheng; Zhang, Yonghe; Zharov, Vladimir; Zhou, Ze-Bing
2016-02-01
TianQin is a proposal for a space-borne detector of gravitational waves in the millihertz frequencies. The experiment relies on a constellation of three drag-free spacecraft orbiting the Earth. Inter-spacecraft laser interferometry is used to monitor the distances between the test masses. The experiment is designed to be capable of detecting a signal with high confidence from a single source of gravitational waves within a few months of observing time. We describe the preliminary mission concept for TianQin, including the candidate source and experimental designs. We present estimates for the major constituents of the experiment’s error budget and discuss the project’s overall feasibility. Given the current level of technological readiness, we expect TianQin to be flown in the second half of the next decade.
Searches for Continuous Gravitational Waves in LIGO and Virgo Data
NASA Astrophysics Data System (ADS)
Riles, Keith; LIGO Scientific Collaboration Collaboration; Virgo Collaboration Collaboration
2017-01-01
The LIGO Scientific Collaboration and Virgo Collaboration have carried out searches for periodic continuous gravitational waves. These analyses range from targeted searches for gravitational-wave signals from known pulsars, for which precise ephemerides from radio or X-ray observations are available, to all-sky searches for unknown neutron stars, including stars in unknown binary systems. Between these extremes lie directed searches for known stars of unknown spin frequency or for new unknown sources at specific locations. These different types of searches will be presented, including final results from the Initial LIGO and Virgo data runs and, where available, new results from searches of early Advanced LIGO data. This work is supported by the National Science Foundation grant PHY-1505932.
An antenna for laser gravitational-wave observations in space
NASA Technical Reports Server (NTRS)
Faller, J. E.; Bender, P. L.; Hall, J. L.; Hils, D.; Stebbins, R. T.
1989-01-01
Progress during the past two years on a proposed Laser Gravitational-Wave Observatory in Space (LAGOS) is discussed. Calculated performance for a 10 to the 6th km sized antenna over the frequency range of 10 to the -5th to 1 Hz is given. The sensitivity from 0.001 to 0.1 Hz is expected to be 1 x 10 to the -21st/Hz exp 0.5. Noise sources such as accelerations of the drag-free test masses by random molecular impacts and by fluctuations in the net thermal radiation pressure will limit the sensitivity at lower frequencies. The scientific objectives are the observation of CW gravitational waves from large numbers of binary systems and the detection of pulses which may have been emitted during the period of galaxy formation.
Leveraging waveform complexity for confident detection of gravitational waves
NASA Astrophysics Data System (ADS)
Kanner, Jonah B.; Littenberg, Tyson B.; Cornish, Neil; Millhouse, Meg; Xhakaj, Enia; Salemi, Francesco; Drago, Marco; Vedovato, Gabriele; Klimenko, Sergey
2016-01-01
The recent completion of Advanced LIGO suggests that gravitational waves may soon be directly observed. Past searches for gravitational-wave transients have been impacted by transient noise artifacts, known as glitches, introduced into LIGO data due to instrumental and environmental effects. In this work, we explore how waveform complexity, instead of signal-to-noise ratio, can be used to rank event candidates and distinguish short duration astrophysical signals from glitches. We test this framework using a new hierarchical pipeline that directly compares the Bayesian evidence of explicit signal and glitch models. The hierarchical pipeline is shown to perform well and, in particular, to allow high-confidence detections of a range of waveforms at a realistic signal-to-noise ratio with a two-detector network.
New method for gravitational wave detection with atomic sensors.
Graham, Peter W; Hogan, Jason M; Kasevich, Mark A; Rajendran, Surjeet
2013-04-26
Laser frequency noise is a dominant noise background for the detection of gravitational waves using long-baseline optical interferometry. Amelioration of this noise requires near simultaneous strain measurements on more than one interferometer baseline, necessitating, for example, more than two satellites for a space-based detector or two interferometer arms for a ground-based detector. We describe a new detection strategy based on recent advances in optical atomic clocks and atom interferometry which can operate at long baselines and which is immune to laser frequency noise. Laser frequency noise is suppressed because the signal arises strictly from the light propagation time between two ensembles of atoms. This new class of sensor allows sensitive gravitational wave detection with only a single baseline. This approach also has practical applications in, for example, the development of ultrasensitive gravimeters and gravity gradiometers.
Modeling Gravitational Waves to Test GR Dispersion and Polarization
NASA Astrophysics Data System (ADS)
Tso, Rhondale; Chen, Yanbei; Isi, Maximilliano
2017-01-01
Given continued observation runs from the Laser Interferometer Gravitational-Wave Observatory Scientific Collaboration, further gravitational wave (GW) events will provide added constraints on beyond-general relativity (b-GR) theories. One approach, independent of the GW generation mechanism at the source, is to look at modification to the GW dispersion and propagation, which can accumulate over vast distances. Generic modification of GW propagation can also, in certain b-GR theories, impact the polarization content of GWs. To this end, a comprehensive approach to testing the dispersion and polarization content is developed by modeling anisotropic deformations to the waveforms' phase, along with birefringence effects and corollary consequences for b-GR polarizations, i.e., breathing, vector, and longitudinal modes. Such an approach can be mapped to specific theories like Lorentz violation, amplitude birefringence in Chern-Simons, and provide hints at additional theories to be included. An overview of data analysis routines to be implemented will also be discussed.
Balanced homodyne readout for quantum limited gravitational wave detectors.
Fritschel, Peter; Evans, Matthew; Frolov, Valery
2014-02-24
Balanced homodyne detection is typically used to measure quantum-noise-limited optical beams, including squeezed states of light, at audio-band frequencies. Current designs of advanced gravitational wave interferometers use some type of homodyne readout for signal detection, in part because of its compatibility with the use of squeezed light. The readout scheme used in Advanced LIGO, called DC readout, is however not a balanced detection scheme. Instead, the local oscillator field, generated from a dark fringe offset, co-propagates with the signal field at the anti-symmetric output of the beam splitter. This article examines the alternative of a true balanced homodyne detection for the readout of gravitational wave detectors such as Advanced LIGO. Several practical advantages of the balanced detection scheme are described.
Prospects for primordial gravitational waves in string inflation
NASA Astrophysics Data System (ADS)
Parameswaran, Susha L.; Zavala, Ivonne
2016-08-01
Assuming that the early universe had (i) a description using perturbative string theory and its field theory limit, (ii) an epoch of slow-roll inflation within a four-dimensional effective field theory and a hierarchy of scales Minf < mkk < ms ≲ MPl that keeps the latter under control, we derive an upper bound on the amplitude of primordial gravitational waves. The bound is very sensitive to mild changes in numerical coefficients and the expansion parameters. For example, allowing couplings and mass-squared hierarchies ≲ 0.2 implies r ≲ 0.05, but asking more safely for hierarchies ≲ 0.1, the bound becomes r ≲ 10-6. Moreover, large volumes — typically used in string models to keep backreaction and moduli stabilization under control — drive r down. Consequently, any detection of inflationary gravitational waves would present an interesting but difficult challenge for string theory.
Charge management for gravitational-wave observatories using UV LEDs
Pollack, S. E.; Turner, M. D.; Schlamminger, S.; Hagedorn, C. A.; Gundlach, J. H.
2010-01-15
Accumulation of electrical charge on the end mirrors of gravitational-wave observatories can become a source of noise limiting the sensitivity of such detectors through electronic couplings to nearby surfaces. Torsion balances provide an ideal means for testing gravitational-wave technologies due to their high sensitivity to small forces. Our torsion pendulum apparatus consists of a movable plate brought near a plate pendulum suspended from a nonconducting quartz fiber. A UV LED located near the pendulum photoejects electrons from the surface, and a UV LED driven electron gun directs photoelectrons towards the pendulum surface. We have demonstrated both charging and discharging of the pendulum with equivalent charging rates of {approx}10{sup 5}e/s, as well as spectral measurements of the pendulum charge resulting in a white noise level equivalent to 3x10{sup 5}e/{radical}(Hz).
Double optical spring enhancement for gravitational-wave detectors
Rehbein, Henning; Mueller-Ebhardt, Helge; Schnabel, Roman; Danzmann, Karsten; Somiya, Kentaro; Chen Yanbei; Danilishin, Stefan L.
2008-09-15
Currently planned second-generation gravitational-wave laser interferometers such as Advanced LIGO exploit the extensively investigated signal-recycling technique. Candidate Advanced LIGO configurations are usually designed to have two resonances within the detection band, around which the sensitivity is enhanced: a stable optical resonance and an unstable optomechanical resonance--which is upshifted from the pendulum frequency due to the so-called optical-spring effect. As an alternative to a feedback control system, we propose an all-optical stabilization scheme, in which a second optical spring is employed, and the test mass is trapped by a stable ponderomotive potential well induced by two carrier light fields whose detunings have opposite signs. The double optical spring also brings additional flexibility in reshaping the noise spectral density and optimizing toward specific gravitational-wave sources. The presented scheme can be extended easily to a multi-optical-spring system that allows further optimization.
First upper limits from LIGO on gravitational wave bursts
B. Abbott et al.
2004-03-09
We report on a search for gravitational wave bursts using data from the first science run of the LIGO detectors. Our search focuses on bursts with durations ranging from 4 ms to 100 ms, and with significant power in the LIGO sensitivity band of 150 to 3000 Hz. We bound the rate for such detected bursts at less than 1.6 events per day at 90% confidence level. This result is interpreted in terms of the detection efficiency for ad hoc waveforms (Gaussians and sine-Gaussians) as a function of their root-sum-square strain h{sub rss}; typical sensitivities lie in the range h{sub rss} {approx} 10{sup -19} - 10{sup -17} strain/{radical}Hz, depending on waveform. We discuss improvements in the search method that will be applied to future science data from LIGO and other gravitational wave detectors.
Strong lensing of gravitational waves as seen by LISA.
Sereno, M; Sesana, A; Bleuler, A; Jetzer, Ph; Volonteri, M; Begelman, M C
2010-12-17
We discuss strong gravitational lensing of gravitational waves from the merging of massive black hole binaries in the context of the LISA mission. Detection of multiple events would provide invaluable information on competing theories of gravity, evolution and formation of structures and, possibly, constraints on H0 and other cosmological parameters. Most of the optical depth for lensing is provided by intervening massive galactic halos, for which wave optics effects are negligible. Probabilities to observe multiple events are sizable for a broad range of formation histories. For the most optimistic models, up to ≲ 4 multiple events with a signal to noise ratio ≳ 8 are expected in a 5-year mission. Chances are significant even for conservative models with either light (≲ 60%) or heavy (≲ 40%) seeds. Because of lensing amplification, some intrinsically too faint signals are brought over threshold (≲ 2 per year).
Limits of Astrophysics with Gravitational-Wave Backgrounds
NASA Astrophysics Data System (ADS)
Callister, Thomas; Sammut, Letizia; Qiu, Shi; Mandel, Ilya; Thrane, Eric
2016-07-01
The recent Advanced LIGO detection of gravitational waves from the binary black hole GW150914 suggests there exists a large population of merging binary black holes in the Universe. Although most are too distant to be individually resolved by advanced detectors, the superposition of gravitational waves from many unresolvable binaries is expected to create an astrophysical stochastic background. Recent results from the LIGO and Virgo Collaborations show that this astrophysical background is within reach of Advanced LIGO. In principle, the binary black hole background encodes interesting astrophysical properties, such as the mass distribution and redshift distribution of distant binaries. However, we show that this information will be difficult to extract with the current configuration of advanced detectors (and using current data analysis tools). Additionally, the binary black hole background also constitutes a foreground that limits the ability of advanced detectors to observe other interesting stochastic background signals, for example, from cosmic strings or phase transitions in the early Universe. We quantify this effect.
Impact of cosmic neutrinos on the gravitational-wave background
Mangilli, Anna; Bartolo, Nicola; Matarrese, Sabino; Riotto, Antonio
2008-10-15
We obtain the equation governing the evolution of the cosmological gravitational-wave background, accounting for the presence of cosmic neutrinos, up to second order in perturbation theory. In particular, we focus on the epoch during radiation dominance, after neutrino decoupling, when neutrinos yield a relevant contribution to the total energy density and behave as collisionless ultrarelativistic particles. Besides recovering the standard damping effect due to neutrinos, a new source term for gravitational waves is shown to arise from the neutrino anisotropic stress tensor. The importance of such a source term, so far completely disregarded in the literature, is related to the high velocity dispersion of neutrinos in the considered epoch; its computation requires solving the full second-order Boltzmann equation for collisionless neutrinos.
Reconstructing the massive black hole cosmic history through gravitational waves
Sesana, Alberto; Gair, Jonathan; Berti, Emanuele; Volonteri, Marta
2011-02-15
The massive black holes we observe in galaxies today are the natural end-product of a complex evolutionary path, in which black holes seeded in proto-galaxies at high redshift grow through cosmic history via a sequence of mergers and accretion episodes. Electromagnetic observations probe a small subset of the population of massive black holes (namely, those that are active or those that are very close to us), but planned space-based gravitational wave observatories such as the Laser Interferometer Space Antenna (LISA) can measure the parameters of 'electromagnetically invisible' massive black holes out to high redshift. In this paper we introduce a Bayesian framework to analyze the information that can be gathered from a set of such measurements. Our goal is to connect a set of massive black hole binary merger observations to the underlying model of massive black hole formation. In other words, given a set of observed massive black hole coalescences, we assess what information can be extracted about the underlying massive black hole population model. For concreteness we consider ten specific models of massive black hole formation, chosen to probe four important (and largely unconstrained) aspects of the input physics used in structure formation simulations: seed formation, metallicity ''feedback'', accretion efficiency and accretion geometry. For the first time we allow for the possibility of 'model mixing', by drawing the observed population from some combination of the 'pure' models that have been simulated. A Bayesian analysis allows us to recover a posterior probability distribution for the ''mixing parameters'' that characterize the fractions of each model represented in the observed distribution. Our work shows that LISA has enormous potential to probe the underlying physics of structure formation.
Gravitational wave emission and spin-down of young pulsars
Alford, Mark G.; Schwenzer, Kai
2014-01-20
The rotation frequencies of young pulsars are systematically below their theoretical Kepler limit. r-modes have been suggested as a possible explanation for this observation. With the help of semi-analytic expressions that make it possible to assess the uncertainties of the r-mode scenario due to the impact of uncertainties in underlying microphysics, we perform a quantitative analysis of the spin-down and the emitted gravitational waves of young pulsars. We find that the frequency to which r-modes spin-down a young neutron star (NS) is surprisingly insensitive to both the microscopic details and the saturation amplitude. Comparing our result to astrophysical data, we show that for a range of sufficiently large saturation amplitudes r-modes provide a viable spin-down scenario and that all observed young pulsars are very likely already outside the r-mode instability region. Therefore, the most promising sources for gravitational wave detection are unobserved NSs associated with recent supernovae, and we find that advanced LIGO should be able to see several of them. Our analysis shows that despite the coupling of the spin-down and thermal evolution, a power-law spin-down with an effective braking index n {sub rm} ≤ 7 is realized. Because of this, the gravitational wave strain amplitude is completely independent of both the r-mode saturation amplitude and the microphysics and depends on the saturation mechanism only within some tens of percent. However, the gravitational wave frequency depends on the amplitude, and we provide the required expected timing parameter ranges to look for promising sources in future searches.
NASA's Preparations for ESA's L3 Gravitational Wave Mission
NASA Astrophysics Data System (ADS)
Stebbins, Robin
2016-03-01
The European Space Agency (ESA) selected gravitational-wave astrophysics as the science theme for its third large mission opportunity, known as `L3,' under its Cosmic Vision Programme. NASA is seeking a role as an international partner in L3. NASA is: (1) participating in ESA's early mission activities, (2) developing potential US technology contributions, (3) participating in ESA's LISA Pathfinder mission, (4) and conducting a study of how NASA might participate. This talk will survey the status of these activities.
Limiting the effects of earthquakes on gravitational-wave interferometers
NASA Astrophysics Data System (ADS)
Coughlin, Michael; Earle, Paul; Harms, Jan; Biscans, Sebastien; Buchanan, Christopher; Coughlin, Eric; Donovan, Fred; Fee, Jeremy; Gabbard, Hunter; Guy, Michelle; Mukund, Nikhil; Perry, Matthew
2017-02-01
Ground-based gravitational wave interferometers such as the Laser Interferometer Gravitational-wave Observatory (LIGO) are susceptible to ground shaking from high-magnitude teleseismic events, which can interrupt their operation in science mode and significantly reduce their duty cycle. It can take several hours for a detector to stabilize enough to return to its nominal state for scientific observations. The down time can be reduced if advance warning of impending shaking is received and the impact is suppressed in the isolation system with the goal of maintaining stable operation even at the expense of increased instrumental noise. Here, we describe an early warning system for modern gravitational-wave observatories. The system relies on near real-time earthquake alerts provided by the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA). Preliminary low latency hypocenter and magnitude information is generally available in 5 to 20 min of a significant earthquake depending on its magnitude and location. The alerts are used to estimate arrival times and ground velocities at the gravitational-wave detectors. In general, 90% of the predictions for ground-motion amplitude are within a factor of 5 of measured values. The error in both arrival time and ground-motion prediction introduced by using preliminary, rather than final, hypocenter and magnitude information is minimal. By using a machine learning algorithm, we develop a prediction model that calculates the probability that a given earthquake will prevent a detector from taking data. Our initial results indicate that by using detector control configuration changes, we could prevent interruption of operation from 40 to 100 earthquake events in a 6-month time-period.
Constraints on primordial density perturbations from induced gravitational waves
Assadullahi, Hooshyar; Wands, David
2010-01-15
We consider the stochastic background of gravitational waves produced during the radiation-dominated hot big bang as a constraint on the primordial density perturbation on comoving length scales much smaller than those directly probed by the cosmic microwave background or large-scale structure. We place weak upper bounds on the primordial density perturbation from current data. Future detectors such as BBO and DECIGO will place much stronger constraints on the primordial density perturbation on small scales.
Gravitational waves from the first order phase transition of the Higgs field at high energy scales
NASA Astrophysics Data System (ADS)
Jinno, Ryusuke; Nakayama, Kazunori; Takimoto, Masahiro
2016-02-01
In a wide class of new physics models, there exist scalar fields that obtain vacuum expectation values of high energy scales. We study the possibility that the standard model Higgs field has experienced first order phase transition at the high energy scale due to the couplings with these scalar fields. We estimate the amount of gravitational waves produced by the phase transition, and discuss observational consequences.
Accelerated gravitational wave parameter estimation with reduced order modeling.
Canizares, Priscilla; Field, Scott E; Gair, Jonathan; Raymond, Vivien; Smith, Rory; Tiglio, Manuel
2015-02-20
Inferring the astrophysical parameters of coalescing compact binaries is a key science goal of the upcoming advanced LIGO-Virgo gravitational-wave detector network and, more generally, gravitational-wave astronomy. However, current approaches to parameter estimation for these detectors require computationally expensive algorithms. Therefore, there is a pressing need for new, fast, and accurate Bayesian inference techniques. In this Letter, we demonstrate that a reduced order modeling approach enables rapid parameter estimation to be performed. By implementing a reduced order quadrature scheme within the LIGO Algorithm Library, we show that Bayesian inference on the 9-dimensional parameter space of nonspinning binary neutron star inspirals can be sped up by a factor of ∼30 for the early advanced detectors' configurations (with sensitivities down to around 40 Hz) and ∼70 for sensitivities down to around 20 Hz. This speedup will increase to about 150 as the detectors improve their low-frequency limit to 10 Hz, reducing to hours analyses which could otherwise take months to complete. Although these results focus on interferometric gravitational wave detectors, the techniques are broadly applicable to any experiment where fast Bayesian analysis is desirable.
Primordial gravitational waves from axion-gauge fields dynamics
NASA Astrophysics Data System (ADS)
Dimastrogiovanni, Emanuela; Fasiello, Matteo; Fujita, Tomohiro
2017-01-01
Inspired by the chromo-natural inflation model of Adshead&Wyman, we reshape its scalar content to relax the tension with current observational bounds. Besides an inflaton, the setup includes a spectator sector in which an axion and SU(2) gauge fields are coupled via a Chern-Simons-type term. The result is a viable theory endowed with an alternative production mechanism for gravitational waves during inflation. The gravitational wave signal sourced by the spectator fields can be much larger than the contribution from standard vacuum fluctuations, it is distinguishable from the latter on the basis of its chirality and, depending on the theory parameters values, also its tilt. This production process breaks the well-known relation between the tensor-to-scalar ratio and the energy scale of inflation. As a result, even if the Hubble rate is itself too small for the vacuum to generate a tensor amplitude detectable by upcoming experiments, this model still supports observable gravitational waves.
Possible Space-Based Gravitational-Wave Observatory Mission Concept
NASA Technical Reports Server (NTRS)
Livas, Jeffrey C.
2015-01-01
The existence of gravitational waves was established by the discovery of the Binary Pulsar PSR 1913+16 by Hulse and Taylor in 1974, for which they were awarded the 1983 Nobel Prize. However, it is the exploitation of these gravitational waves for the extraction of the astrophysical parameters of the sources that will open the first new astronomical window since the development of gamma ray telescopes in the 1970's and enable a new era of discovery and understanding of the Universe. Direct detection is expected in at least two frequency bands from the ground before the end of the decade with Advanced LIGO and Pulsar Timing Arrays. However, many of the most exciting sources will be continuously observable in the band from 0.1-100 mHz, accessible only from space due to seismic noise and gravity gradients in that band that disturb ground-based observatories. This poster will discuss a possible mission concept, Space-based Gravitational-wave Observatory (SGO-Mid) developed from the original Laser Interferometer Space Antenna (LISA) reference mission but updated to reduce risk and cost.
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, John
2007-01-01
The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GE0600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, data analysis, and astrophysics.
Merging Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan M.
2009-01-01
The final merger of two black holes will emit more energy than all the stars in the observable universe combined. This energy will come in the form of gravitational waves, which are a key prediction of Einstein's general relativity and a new tool for exploring the universe. Observing these mergers with gravitational wave detectors, such as the ground-based LIGO and the space-based LISA, requires knowledge of the radiation waveforms. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes were long plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and w aefo rms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.
Observing gravitational-wave transient GW150914 with minimal assumptions
NASA Astrophysics Data System (ADS)
Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackburn, L.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, C.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Calderón Bustillo, J.; Callister, T.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Casanueva Diaz, J.; Casentini, C.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Cerboni Baiardi, L.; Cerretani, G.; Cesarini, E.; Chakraborty, R.; Chatterji, S.; Chalermsongsak, T.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, H. Y.; Chen, Y.; Cheng, C.; Chincarini, A.; Chiummo, A.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Clark, M.; Cleva, F.; Coccia, E.; Cohadon, P.-F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, C. A.; Coughlin, M. W.; Coughlin, S. B.; Coulon, J.-P.; Countryman, S. T.; Couvares, P.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Darman, N. S.; Dattilo, V.; Dave, I.; Daveloza, H. P.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; DeRosa, R. T.; De Rosa, R.; DeSalvo, R.; Dhurandhar, S.; Díaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Engels, W.; Essick, R. C.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H. A. G.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gatto, A.; Gaur, G.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Haas, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hinder, I.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J.-M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, C.; Kim, J.; Kim, K.; Kim, Nam-Gyu; Kim, Namjun; Kim, Y.-M.; King, E. J.; King, P. J.; Kinsey, M.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Laguna, P.; Landry, M.; Lange, J.; Lantz, B.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B. M.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Lockerbie, N. A.; Logue, J.; Lombardi, A. L.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lück, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña-Sandoval, F.; Magee, R. M.; Mageswaran, M.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Murphy, D. J.; Murray, P. G.; Mytidis, A.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, M.; Neunzert, A.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Nocera, F.; Nolting, D.; Normandin, M. E.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Page, J.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Patrick, Z.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Phelps, M.; Piccinni, O.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S. S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sanchez, E. J.; Sandberg, V.; Sandeen, B.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, N. D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trifirò, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, X.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Weßels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Worden, J.; Wright, J. L.; Wu, G.; Yablon, J.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, H.; Yvert, M.; ZadroŻny, A.; Zangrando, L.; Zanolin, M.; Zendri, J.-P.; Zevin, M.; Zhang, F.; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, X. J.; Zucker, M. E.; Zuraw, S. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration
2016-06-01
The gravitational-wave signal GW150914 was first identified on September 14, 2015, by searches for short-duration gravitational-wave transients. These searches identify time-correlated transients in multiple detectors with minimal assumptions about the signal morphology, allowing them to be sensitive to gravitational waves emitted by a wide range of sources including binary black hole mergers. Over the observational period from September 12 to October 20, 2015, these transient searches were sensitive to binary black hole mergers similar to GW150914 to an average distance of ˜600 Mpc . In this paper, we describe the analyses that first detected GW150914 as well as the parameter estimation and waveform reconstruction techniques that initially identified GW150914 as the merger of two black holes. We find that the reconstructed waveform is consistent with the signal from a binary black hole merger with a chirp mass of ˜30 M⊙ and a total mass before merger of ˜70 M⊙ in the detector frame.
Accelerated Gravitational Wave Parameter Estimation with Reduced Order Modeling
NASA Astrophysics Data System (ADS)
Canizares, Priscilla; Field, Scott E.; Gair, Jonathan; Raymond, Vivien; Smith, Rory; Tiglio, Manuel
2015-02-01
Inferring the astrophysical parameters of coalescing compact binaries is a key science goal of the upcoming advanced LIGO-Virgo gravitational-wave detector network and, more generally, gravitational-wave astronomy. However, current approaches to parameter estimation for these detectors require computationally expensive algorithms. Therefore, there is a pressing need for new, fast, and accurate Bayesian inference techniques. In this Letter, we demonstrate that a reduced order modeling approach enables rapid parameter estimation to be performed. By implementing a reduced order quadrature scheme within the LIGO Algorithm Library, we show that Bayesian inference on the 9-dimensional parameter space of nonspinning binary neutron star inspirals can be sped up by a factor of ˜30 for the early advanced detectors' configurations (with sensitivities down to around 40 Hz) and ˜70 for sensitivities down to around 20 Hz. This speedup will increase to about 150 as the detectors improve their low-frequency limit to 10 Hz, reducing to hours analyses which could otherwise take months to complete. Although these results focus on interferometric gravitational wave detectors, the techniques are broadly applicable to any experiment where fast Bayesian analysis is desirable.
Probing the Internal Composition of Neutron Stars with Gravitational Waves
NASA Astrophysics Data System (ADS)
Chatziioannou, Katerina; Yagi, Kent; Klein, Antoine; Cornish, Neil; Yunes, Nicolas
2016-03-01
Gravitational waves from neutron star binaries carry information about the equation of state of supranuclear matter through a parameter called tidal deformability. This parameter measures the quadrupole deformation of a neutron star in the presence of an external field. Its measurability has been assessed in a number of studies, concluding it could provide important information about the equation of state of neutron star matter. In this talk, I will describe a complimentary approach to the problem of equation of state determination, one which focuses on how information from gravitational waves can be translated in ways that could be of direct benefit to nuclear physicists. Specifically, I will talk about what gravitational waves can tell us about the internal composition of neutron stars, information that is directly applicable to equation of state modeling. I will also briefly discuss the importance of spin-induced precession in the quality of information extracted. We acknowledge support from the Onassis Foundation, NSF CAREER Grant PHY-1250636, NSF Award PHY-1306702, and NSF CAREER Grant PHY-1055103.
Exploring Sources of Gravitational Waves From Star Cluster Dynamics
NASA Astrophysics Data System (ADS)
Fuhrman, Joshua; Geller, Aaron M.; Rodriguez, Carl L.; Rasio, Frederic A.
2017-01-01
The recent detection of ripples in space-time by the Laser Interferometer Gravitational-wave Observatory (LIGO) has ushered in the age of gravitational wave astronomy. Binary black hole systems formed in the center of modest star clusters offer a possible gravitational wave source detectable by the LIGO or Laser Interferometer Space Antennae (LISA) collaborations. We simulate clusters containing 1-40K objects using direct integration from a customized version of NBODY6++GPU. We identify Binary Black Hole (BBH) objects of interest by an inspiral time sufficiently less than the age of the universe such that their coalescence might be detectable. Such objects are tracked through time within our N-body simulations to characterize the role of dynamics in the evolution of the BBH system using member exchanges and large orbital eccentricity changes as indicators of dynamic’s influence. We produce 41 BBH system candidates for detection by LIGO, all of which are dynamically formed. We observe several trends in the production of these potential BBH LIGO sources: a low-N cutoff in initial cluster size between 1-5K objects, high eccentricity oscillations, and the frequent formation of stable triple systems with the BBH as the inner binary.
The detection of gravitational waves using electrodynamic system of Earth
NASA Astrophysics Data System (ADS)
Grunskaya, Lubov; Isakevich, Valiriy
There is studied the interconnection of tide processes of geophysical and astrophysical origin with the Earth electromagnetic fields. There has been developed a programme-analytical system (PAS) to investigate signal structures in spectral and time series, caused by geophysical and astrophysical processes based on the method of eigen vectors. There were discovered frequencies in the electrical and geomagnetical field of ELF range with PAS, which coincide with the frequency of gravitational -wave radiation of a number of double stellar systems. In the electrical and geomagnetic field there was discovered a specific axion frequency VA=0.5*10-5 Hz belonging to the ELF range which was predicted by the theory. The problem of the anomalous behavior of the electrodynamic system response to the gravitational - wave affect is being discussed. On the basis of the rich experimental material have been investigated the frequencies of gravitational-wave radiation of a number of binary systems: J0700+6418, J1012+5307, J1537+1155, J1959+2048, J2130+1210, J1915+1606. The work is carried out with supporting of RFFI № 14-07-97510, State Task to Universities on 2014-2016.
Experimental bounds on collapse models from gravitational wave detectors
NASA Astrophysics Data System (ADS)
Carlesso, Matteo; Bassi, Angelo; Falferi, Paolo; Vinante, Andrea
2016-12-01
Wave function collapse models postulate a fundamental breakdown of the quantum superposition principle at the macroscale. Therefore, experimental tests of collapse models are also fundamental tests of quantum mechanics. Here, we compute the upper bounds on the collapse parameters, which can be inferred by the gravitational wave detectors LIGO, LISA Pathfinder, and AURIGA. We consider the most widely used collapse model, the continuous spontaneous localization (CSL) model. We show that these experiments exclude a huge portion of the CSL parameter space, the strongest bound being set by the recently launched space mission LISA Pathfinder. We also rule out a proposal for quantum-gravity-induced decoherence.
Testing General Relativity with Low-Frequency, Space-Based Gravitational-Wave Detectors.
Gair, Jonathan R; Vallisneri, Michele; Larson, Shane L; Baker, John G
2013-01-01
We review the tests of general relativity that will become possible with space-based gravitational-wave detectors operating in the ∼ 10(-5) - 1 Hz low-frequency band. The fundamental aspects of gravitation that can be tested include the presence of additional gravitational fields other than the metric; the number and tensorial nature of gravitational-wave polarization states; the velocity of propagation of gravitational waves; the binding energy and gravitational-wave radiation of binaries, and therefore the time evolution of binary inspirals; the strength and shape of the waves emitted from binary mergers and ringdowns; the true nature of astrophysical black holes; and much more. The strength of this science alone calls for the swift implementation of a space-based detector; the remarkable richness of astrophysics, astronomy, and cosmology in the low-frequency gravitational-wave band make the case even stronger.
On the unreasonable effectiveness of the post-Newtonian approximation in gravitational physics
Will, Clifford M.
2011-01-01
The post-Newtonian approximation is a method for solving Einstein’s field equations for physical systems in which motions are slow compared to the speed of light and where gravitational fields are weak. Yet it has proven to be remarkably effective in describing certain strong-field, fast-motion systems, including binary pulsars containing dense neutron stars and binary black hole systems inspiraling toward a final merger. The reasons for this effectiveness are largely unknown. When carried to high orders in the post-Newtonian sequence, predictions for the gravitational-wave signal from inspiraling compact binaries will play a key role in gravitational-wave detection by laser-interferometric observatories. PMID:21447714
Gravitational waves from gamma-ray pulsar glitches
Stopnitzky, Elan; Profumo, Stefano
2014-06-01
We use data from pulsar gamma-ray glitches recorded by the Fermi Large Area Telescope as input to theoretical models of gravitational wave signals the glitches might generate. We find that the typical peak amplitude of the gravity wave signal from gamma-ray pulsar glitches lies between 10{sup –23} and 10{sup –35} in dimensionless units, with peak frequencies in the range of 1 to 1000 Hz, depending on the model. We estimate the signal-to-noise ratio (S/N) for all gamma-ray glitches, and discuss detectability with current gravity wave detectors. Our results indicate that the strongest predicted signals are potentially within reach of current detectors, and that pulsar gamma-ray glitches are promising targets for gravity wave searches by current and next-generation detectors.
Porting Gravitational Wave Signal Extraction to Parallel Virtual Machine (PVM)
NASA Technical Reports Server (NTRS)
Thirumalainambi, Rajkumar; Thompson, David E.; Redmon, Jeffery
2009-01-01
Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA mission to be launched around 2012. The Gravitational Wave detection is fundamentally the determination of frequency, source parameters, and waveform amplitude derived in a specific order from the interferometric time-series of the rotating LISA spacecrafts. The LISA Science Team has developed a Mock LISA Data Challenge intended to promote the testing of complicated nested search algorithms to detect the 100-1 millihertz frequency signals at amplitudes of 10E-21. However, it has become clear that, sequential search of the parameters is very time consuming and ultra-sensitive; hence, a new strategy has been developed. Parallelization of existing sequential search algorithms of Gravitational Wave signal identification consists of decomposing sequential search loops, beginning with outermost loops and working inward. In this process, the main challenge is to detect interdependencies among loops and partitioning the loops so as to preserve concurrency. Existing parallel programs are based upon either shared memory or distributed memory paradigms. In PVM, master and node programs are used to execute parallelization and process spawning. The PVM can handle process management and process addressing schemes using a virtual machine configuration. The task scheduling and the messaging and signaling can be implemented efficiently for the LISA Gravitational Wave search process using a master and 6 nodes. This approach is accomplished using a server that is available at NASA Ames Research Center, and has been dedicated to the LISA Data Challenge Competition. Historically, gravitational wave and source identification parameters have taken around 7 days in this dedicated single thread Linux based server. Using PVM approach, the parameter extraction problem can be reduced to within a day. The low frequency computation and a proxy signal-to-noise ratio are calculated in separate nodes that are controlled by the master
Primordial gravitational waves in bimetric gravity
Sakakihara, Yuki; Soda, Jiro E-mail: jiro@phys.sci.kobe-u.ac.jp
2015-09-01
We study primordial tensor power-spectra generated during inflation in bimetric gravity. More precisely, we examine a homogeneous expanding spacetime in a minimal bimetric model with an inflaton and calculate tensor perturbations on the homogeneous background under slow-roll approximation. In terms of the mass eigenstates, only the power-spectrum of the massless state remains constant and both the power-spectrum of the massive state and the cross power-spectrum rapidly decay during inflation. The amplitude of the physical power-spectrum is suppressed due to the flavor mixing. All power-spectra in the flavor eigenstates coincide with each other up to the first order of the slow-roll parameter.
Laser Interferometry for Gravitational Wave Observation: LISA and LISA Pathfinder
NASA Technical Reports Server (NTRS)
Guzman, Felipe
2010-01-01
The Laser Interferometer Space Antenna (LISA) is a planned NASA-ESA gravitational wave observatory in the frequency range of 0.1mHz-100mHz. This observation band is inaccessible to ground-based detectors due to the large ground motions of the Earth. Gravitational wave sources for LISA include galactic binaries, mergers of supermasive black-hole binaries, extreme-mass-ratio inspirals, and possibly from as yet unimagined sources. LISA is a constellation of three spacecraft separated by 5 million km in an equilateral triangle, whose center follows the Earth in a heliocentric orbit with an orbital phase offset oF 20 degrees. Challenging technology is required to ensure pure geodetic trajectories of the six onboard test masses, whose distance fluctuations will be measured by interspacecraft laser interferometers with picometer accuracy. LISA Pathfinder is an ESA-launched technology demonstration mission of key LISA subsystems such us spacecraft control with micro-newton thrusters, test mass drag-free control, and precision laser interferometry between free-flying test masses. Ground testing of flight hardware of the Gravitational Reference Sensor and Optical Metrology subsystems of LISA Pathfinder is currently ongoing. An introduction to laser interferometric gravitational wave detection, ground-based observatories, and a detailed description of the two missions together with an overview of current investigations conducted by the community will bc discussed. The current status in development and implementation of LISA Pathfinder pre-flight systems and latest results of the ongoing ground testing efforts will also be presented
Gravitational waves from direct collapse black holes formation
NASA Astrophysics Data System (ADS)
Pacucci, Fabio; Ferrara, Andrea; Marassi, Stefania
2015-05-01
The possible formation of direct collapse black holes (DCBHs) in the first metal-free atomic cooling haloes at high redshifts (z ≳ 10) is nowadays object of intense study and several methods to prove their existence are currently under development. The abrupt collapse of a massive (˜104-105 M⊙) and rotating object is a powerful source of gravitational waves emission. In this work, we employ modern waveforms and the improved knowledge on the DCBHs formation rate to estimate the gravitational signal emitted by these sources at cosmological distances. Their formation rate is very high (˜104 yr-1 up to z ˜ 20), but due to a short duration of the collapse event (˜2-30 s, depending on the DCBH mass), the integrated signal from these sources is characterized by a very low duty-cycle (D˜ 10^{-3}), i.e. a shot-noise signal. Our results show that the estimated signal lies above the foreseen sensitivity of the Ultimate-Deci-hertz Interferometer Gravitational wave Observatory in the frequency range (0.8-300) mHz, with a peak amplitude Ωgw = 1.1 × 10-54 at νmax = 0.9 mHz and a peak signal-to-noise ratio SNR ˜ 22 at ν = 20 mHz. This amplitude is lower than the Galactic confusion noise, generated by binary systems of compact objects in the same frequency band. For this reason, advanced techniques will be required to separate this signal from background and foreground noise components. As a proof-of-concept, we conclude by proposing a simple method, based on the autocorrelation function, to recognize the presence of a D ≪ 1 signal buried into the continuous noise. The aim of this work is to test the existence of a large population of high-z DCBHs, by observing the gravitational waves emitted during their infancy.
Narrowing the Search After Gravitational-Wave Detections
NASA Astrophysics Data System (ADS)
Kohler, Susanna
2016-11-01
Now that were able to detect gravitational waves, the next challenge is to spot electromagnetic signatures associated with gravitational-wave events. A team of scientists has proposed a new algorithm that might narrow the search.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)]Light from Neutron-Star MergersJust over a year ago, LIGO detected its first gravitational-wave signal: GW150914, produced when two black holes merged. While we didnt expect to see any sort of light-based signal from this merger, we could expect to see transient electromagnetic signatures in the case of a neutron starblack hole merger or a neutron starneutron star merger in the form of a kilonova or a short gamma-ray burst.While we havent yet detected any mergers involving neutron stars, LIGO has the sensitivity to make these detections in the local universe, and we hope to start seeing them soon! Finding the electromagnetic companions to gravitational-wave signals would be the best way to probe the evolution history of the universe and learn what happens when evolved stars collide. So how do we hunt them down?2D localization maps for LIGOs detection of GW150914 (black contours), as well as the footprints of follow-up observations (red for radio, green for optical/IR, blue for X-ray). [Abbott et al. 2016]Pinpointing a VolumeThe two LIGO detectors can already provide rough 2D localization of where the gravitational-wave signal came from, but the region predicted for GW150914 still covered 600 square degrees, which is a pretty hefty patch of sky! In light of this, the simplest follow-up strategy of tiling large survey observations of the entire predicted region is somewhat impractical and time
Non-linear Oscillations of Compact Stars and Gravitational Waves
NASA Astrophysics Data System (ADS)
Passamonti, Andrea
2006-07-01
This thesis investigates in the time domain a particular class of second order perturbations of a perfect fluid non-rotating compact star: those arising from the coupling between first order radial and non-radial perturbations. This problem has been treated by developing a gauge invariant formalism based on the 2-parameter perturbation theory (Sopuerta, Bruni and Gualtieri, 2004) where the radial and non-radial perturbations have been separately parameterized. The non-linear perturbations obey inhomogeneous partial differential equations, where the structure of the differential operator is given by the previous perturbative orders and the source terms are quadratic in the first order perturbations. In the exterior spacetime the sources vanish, thus the gravitational wave properties are completely described by the second order Zerilli and Regge-Wheeler functions. As main initial configuration we have considered a first order differentially rotating and radially pulsating star. Although at first perturbative order this configuration does not exhibit any gravitational radiation, we have found a new interesting gravitational signal at non-linear order, in which the radial normal modes are precisely mirrored. In addition, a resonance effect is present when the frequencies of the radial pulsations are close to the first axial w-mode. Finally, we have roughly estimated the damping times of the radial pulsations due to the non-linear gravitational emission. The coupling near the resonance results to be a very effective mechanism for extracting energy from the radial oscillations.
Choreography and Gravitational Waves for 2-BODY and 3-BODY Gravitating Systems
NASA Astrophysics Data System (ADS)
Asada, Hideki
In the framework of general relativity, we discuss choreographic solutions for the three-body problem, where a solution is called choreographic if every massive particles move periodically in a single closed orbit. In general relativity, the periastron shift prohibits a binary system from orbiting in a single closed curve. Remarkably, a "figure-eight" solution is shown to be choreographic even at the PN approximation by carefully examining initial conditions. Next, gravitational waves for two- and three-body gravitating systems are discussed as an inverse problem. It is shown that quadrupole waveforms cannot distinguish these sources at particular configurations, especially through extending the definition of the chirp mass to such a three-body system. Finally, we present a conjecture on N particles for classification of sources with multipolar waveforms.
Gravitational wave extraction in simulations of rotating stellar core collapse
Reisswig, C.; Ott, C. D.; Sperhake, U.; Schnetter, E.
2011-03-15
We perform simulations of general relativistic rotating stellar core collapse and compute the gravitational waves (GWs) emitted in the core-bounce phase of three representative models via multiple techniques. The simplest technique, the quadrupole formula (QF), estimates the GW content in the spacetime from the mass-quadrupole tensor only. It is strictly valid only in the weak-field and slow-motion approximation. For the first time, we apply GW extraction methods in core collapse that are fully curvature based and valid for strongly radiating and highly relativistic sources. These techniques are not restricted to weak-field and slow-motion assumptions. We employ three extraction methods computing (i) the Newman-Penrose (NP) scalar {Psi}{sub 4}, (ii) Regge-Wheeler-Zerilli-Moncrief master functions, and (iii) Cauchy-characteristic extraction (CCE) allowing for the extraction of GWs at future null infinity, where the spacetime is asymptotically flat and the GW content is unambiguously defined. The latter technique is the only one not suffering from residual gauge and finite-radius effects. All curvature-based methods suffer from strong nonlinear drifts. We employ the fixed-frequency integration technique as a high-pass waveform filter. Using the CCE results as a benchmark, we find that finite-radius NP extraction yields results that agree nearly perfectly in phase, but differ in amplitude by {approx}1%-7% at core bounce, depending on the model. Regge-Wheeler-Zerilli-Moncrief waveforms, while, in general, agreeing in phase, contain spurious high-frequency noise of comparable amplitudes to those of the relatively weak GWs emitted in core collapse. We also find remarkably good agreement of the waveforms obtained from the QF with those obtained from CCE. The results from QF agree very well in phase and systematically underpredict peak amplitudes by {approx}5%-11%, which is comparable to the NP results and is certainly within the uncertainties associated with core collapse
Balbus, Steven A
2016-10-18
A conserved stress energy tensor for weak field gravitational waves propagating in vacuum is derived directly from the linearized general relativistic wave equation alone, for an arbitrary gauge. In any harmonic gauge, the form of the tensor leads directly to the classical expression for the outgoing wave energy. The method described here, however, is a much simpler, shorter, and more physically motivated approach than is the customary procedure, which involves a lengthy and cumbersome second-order (in wave-amplitude) calculation starting with the Einstein tensor. Our method has the added advantage of exhibiting the direct coupling between the outgoing wave energy flux and the work done by the gravitational field on the sources. For nonharmonic gauges, the directly derived wave stress tensor has an apparent index asymmetry. This coordinate artifact may be straightforwardly removed, and the symmetrized (still gauge-invariant) tensor then takes on its widely used form. Angular momentum conservation follows immediately. For any harmonic gauge, however, the stress tensor found is manifestly symmetric from the start, and its derivation depends, in its entirety, on the structure of the linearized wave equation.
NASA Astrophysics Data System (ADS)
Takahashi, Ryuichi
2017-01-01
In this study we demonstrate that general relativity predicts arrival time differences between gravitational wave (GW) and electromagnetic (EM) signals caused by the wave effects in gravitational lensing. The GW signals can arrive earlier than the EM signals in some cases if the GW/EM signals have passed through a lens, even if both signals were emitted simultaneously by a source. GW wavelengths are much larger than EM wavelengths; therefore, the propagation of the GWs does not follow the laws of geometrical optics, including the Shapiro time delay, if the lens mass is less than approximately 105 M⊙(f/Hz)‑1, where f is the GW frequency. The arrival time difference can reach ∼0.1 s (f/Hz)‑1 if the signals have passed by a lens of mass ∼8000 M⊙(f/Hz)‑1 with the impact parameter smaller than the Einstein radius; therefore, it is more prominent for lower GW frequencies. For example, when a distant supermassive black hole binary (SMBHB) in a galactic center is lensed by an intervening galaxy, the time lag becomes of the order of 10 days. Future pulsar timing arrays including the Square Kilometre Array and X-ray detectors may detect several time lags by measuring the orbital phase differences between the GW/EM signals in the SMBHBs. Gravitational lensing imprints a characteristic modulation on a chirp waveform; therefore, we can deduce whether a measured arrival time lag arises from intrinsic source properties or gravitational lensing. Determination of arrival time differences would be extremely useful in multimessenger observations and tests of general relativity.
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan
2008-01-01
The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields. We need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan
2008-01-01
The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
Massive black hole (MBH) binaries are found at the centers of most galaxies. MBH mergers trace galaxy mergers and are strong sources of gravitational waves. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities. causing them to crash well before the black hole:, in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This presentation shows how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. Focus is on the recent advances that that reveal these waveforms, and the potential for discoveries that arises when these sources are observed by LIGO and LISA.
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan
2008-01-01
The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities. causing them to crash well before the black hole:, in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan
2009-01-01
The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Recently this situation has changed dramatically, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simutation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LIGO and LISA.
Delensing gravitational wave standard sirens with shear and flexion maps
NASA Astrophysics Data System (ADS)
Shapiro, C.; Bacon, D. J.; Hendry, M.; Hoyle, B.
2010-05-01
Supermassive black hole binary (SMBHB) systems are standard sirens - the gravitational wave analogue of standard candles - and if discovered by gravitational wave detectors, they could be used as precise distance indicators. Unfortunately, gravitational lensing will randomly magnify SMBHB signals, seriously degrading any distance measurements. Using a weak lensing map of the SMBHB line of sight, we can estimate its magnification and thereby remove some uncertainty in its distance, a procedure we call `delensing'. We find that delensing is significantly improved when galaxy shears are combined with flexion measurements, which reduce small-scale noise in reconstructed magnification maps. Under a Gaussian approximation, we estimate that delensing with a 2D mosaic image from an Extremely Large Telescope could reduce distance errors by about 25-30 per cent for an SMBHB at z = 2. Including an additional wide shear map from a space survey telescope could reduce distance errors by nearly a factor of 2. Such improvement would make SMBHBs considerably more valuable as cosmological distance probes or as a fully independent check on existing probes.
SPINDOWN OF ISOLATED NEUTRON STARS: GRAVITATIONAL WAVES OR MAGNETIC BRAKING?
Staff, Jan E.; Jaikumar, Prashanth; Chan, Vincent; Ouyed, Rachid
2012-05-20
We study the spindown of isolated neutron stars from initially rapid rotation rates, driven by two factors: (1) gravitational wave emission due to r-modes and (2) magnetic braking. In the context of isolated neutron stars, we present the first study including self-consistently the magnetic damping of r-modes in the spin evolution. We track the spin evolution employing the RNS code, which accounts for the rotating structure of neutron stars for various equations of state. We find that, despite the strong damping due to the magnetic field, r-modes alter the braking rate from pure magnetic braking for B {<=} 10{sup 13} G. For realistic values of the saturation amplitude {alpha}{sub sat}, the r-mode can also decrease the time to reach the threshold central density for quark deconfinement. Within a phenomenological model, we assess the gravitational waveform that would result from r-mode-driven spindown of a magnetized neutron star. To contrast with the persistent signal during the spindown phase, we also present a preliminary estimate of the transient gravitational wave signal from an explosive quark-hadron phase transition, which can be a signal for the deconfinement of quarks inside neutron stars.
Roever, Christian; Bizouard, Marie-Anne; Christensen, Nelson; Dimmelmeier, Harald; Heng, Ik Siong; Meyer, Renate
2009-11-15
Presented in this paper is a technique that we propose for extracting the physical parameters of a rotating stellar core collapse from the observation of the associated gravitational wave signal from the collapse and core bounce. Data from interferometric gravitational wave detectors can be used to provide information on the mass of the progenitor model, precollapse rotation, and the nuclear equation of state. We use waveform libraries provided by the latest numerical simulations of rotating stellar core collapse models in general relativity, and from them create an orthogonal set of eigenvectors using principal component analysis. Bayesian inference techniques are then used to reconstruct the associated gravitational wave signal that is assumed to be detected by an interferometric detector. Posterior probability distribution functions are derived for the amplitudes of the principal component analysis eigenvectors, and the pulse arrival time. We show how the reconstructed signal and the principal component analysis eigenvector amplitude estimates may provide information on the physical parameters associated with the core collapse event.
Late-time quadrupolar gravitational wave power in de Sitter space
NASA Astrophysics Data System (ADS)
Hazboun, Jeffrey
2017-01-01
We have calculated the power emitted by a binary system in a cosmological context modeled by a stress energy source on a de Sitter background. The calculation is based on the quadrupole formula for late-time gravitational waves in de Sitter space put forward by Ashtekar, Bonga and Kesavan. There is little reason to expect, a priori, that the projection operator usually used to find the transverse-traceless components of a tensor in asymptotically flat spaces will accurately characterize the physical degrees of freedom in an asymptotically de Sitter spacetime. Instead we use the differential recipe that is true in general, but cumbersome to solve explicitly. The solution presented is based on a conformally transformed version of the quadrupole moment from a Minkowski spacetime for a stable circular binary. A process for calculating the late time power is presented, which coincides with future null infinity. Progress on time dependent results will also be presented. We will discuss the physicality of these results and compare it to other results for gravitational waves in de Sitter space, including recent results on gravitational wave memory.
NASA Astrophysics Data System (ADS)
Rakhmanov, Malik
2014-04-01
Fermi-normal (FN) coordinates provide a standardized way to describe the effects of gravitation from the point of view of an inertial observer. These coordinates have always been introduced via perturbation expansions and were usually limited to distances much less than the characteristic length scale set by the curvature of spacetime. For a plane gravitational wave this scale is given by its wavelength which defines the domain of validity for these coordinates known as the long-wavelength regime. The symmetry of this spacetime, however, allows us to extend FN coordinates far beyond the long-wavelength regime. Here we present an explicit construction for this long-range FN coordinate system based on the unique solution of the boundary-value problem for spacelike geodesics. The resulting formulae amount to summation of the infinite series for FN coordinates previously obtained with perturbation expansions. We also consider two closely related normal-coordinate systems: optical coordinates which are built from null geodesics and wave-synchronous coordinates which are built from spacelike geodesics locked in phase with the propagating gravitational wave. The wave-synchronous coordinates yield the exact solution of Peres and Ehlers-Kundt which is globally defined. In this case, the limitation of the long-wavelength regime is completely overcome, and the system of wave-synchronous coordinates becomes valid for arbitrarily large distances. Comparison of the different coordinate systems is done by considering the motion of an inertial test mass in the field of a plane gravitational wave.
Modeling the Complete Gravitational Wave Spectrum of Neutron Star Mergers.
Bernuzzi, Sebastiano; Dietrich, Tim; Nagar, Alessandro
2015-08-28
In the context of neutron star mergers, we study the gravitational wave spectrum of the merger remnant using numerical relativity simulations. Postmerger spectra are characterized by a main peak frequency f2 related to the particular structure and dynamics of the remnant hot hypermassive neutron star. We show that f(2) is correlated with the tidal coupling constant κ(2)^T that characterizes the binary tidal interactions during the late-inspiral merger. The relation f(2)(κ(2)^T) depends very weakly on the binary total mass, mass ratio, equation of state, and thermal effects. This observation opens up the possibility of developing a model of the gravitational spectrum of every merger unifying the late-inspiral and postmerger descriptions.
Lensing of 21-cm fluctuations by primordial gravitational waves.
Book, Laura; Kamionkowski, Marc; Schmidt, Fabian
2012-05-25
Weak-gravitational-lensing distortions to the intensity pattern of 21-cm radiation from the dark ages can be decomposed geometrically into curl and curl-free components. Lensing by primordial gravitational waves induces a curl component, while the contribution from lensing by density fluctuations is strongly suppressed. Angular fluctuations in the 21-cm background extend to very small angular scales, and measurements at different frequencies probe different shells in redshift space. There is thus a huge trove of information with which to reconstruct the curl component of the lensing field, allowing tensor-to-scalar ratios conceivably as small as r~10(-9)-far smaller than those currently accessible-to be probed.
Searches for electromagnetic signatures of gravitational wave sources
NASA Astrophysics Data System (ADS)
Soares-Santos, Marcelle
2017-01-01
Motivated by the exciting prospect of new wealth of information that will arise from observations of gravitational and electromagnetic radiation from the same astrophysical phenomena, our community has performed a broad range of follow-up programs for LIGO/Virgo events. In this talk, I present an overview of this effort, including results of searches for signatures of the first two LIGO-triggered binary black hole mergers in the 2015-2016 observing campaign, when multiple facilities reported searches in gamma/X-rays, optical, infra-red, and radio wavelengths. I will also discuss plans for upcoming observing campaigns and long term prospects for this exciting emerging field: multi-messenger astrophysics with gravitational waves.
Gravitational Wave Multi-Messenger Prospects for Pulsar Timing Arrays
NASA Astrophysics Data System (ADS)
Simon, Joseph; Burke-Spolaor, Sarah
2017-01-01
Pulsar Timing Array (PTA) experiments are currently setting limits on the gravitational wave (GW) emission in the nanohertz frequency band. The primary source of GW emission in this band is expected to be a population of binary supermassive black holes (SMBHs) that form following galactic mergers. This population of binary supermassive black holes is representative of a crucial step in galaxy formation theories. During this process, there is the potential for many electromagnetic tracers to accompany the binary's evolution. In this talk, I will present recent work investigating the potential for jointly detecting a binary's electromagnetic and gravitational radiation. Such `multi-messenger' sources would provide a unique window into a pivotal stage of galaxy evolution, and would revolutionize the understanding of late-stage galaxy evolution.
Gravitational Wave Multi-Messenger Prospects for Pulsar Timing Arrays
NASA Astrophysics Data System (ADS)
Simon, Joseph; Burke-Spolaor, Sarah
2017-01-01
Pulsar Timing Array (PTA) experiments are now setting limits on the gravitational wave (GW) emission in the nanohertz frequency band. The primary source of GW emission in this band is expected to be a population of binary supermassive black holes (SMBHs) that form following galactic mergers. This population of binary supermassive black holes are representative of a crucial step in galaxy formation theories. During the extended interaction between SMBHs and their host galaxy throughout inspiral, there is the potential for many electromagnetic tracers to accompany the binary's evolution. Using results from a suite of simulations, I will present an investigation of the potential for jointly detecting a binary’s electromagnetic and gravitational radiation. The detection of a single ‘multi-messenger' source would provide a unique window into a pivotal stage of galaxy evolution, and would revolutionize the understanding of late-stage galaxy evolution.
Modeling a nonperturbative spinor vacuum interacting with a strong gravitational wave
NASA Astrophysics Data System (ADS)
Dzhunushaliev, Vladimir; Folomeev, Vladimir
2015-07-01
We consider the propagation of strong gravitational waves interacting with a nonperturbative vacuum of spinor fields. To described the latter, we suggest an approximate model. The corresponding Einstein equation has the form of the Schrödinger equation. Its gravitational-wave solution is analogous to the solution of the Schrödinger equation for an electron moving in a periodic potential. The general solution for the periodic gravitational waves is found. The analog of the Kronig-Penney model for gravitational waves is considered. It is shown that the suggested gravitational-wave model permits the existence of weak electric charge and current densities concomitant with the gravitational wave. Based on this observation, a possible experimental verification of the model is suggested.
Progresses of Search for Gravitational Wave Events Using TAMA300 Data
NASA Astrophysics Data System (ADS)
Kanda, N.; Ando, M.; Nakano, H.; Soida, K.; Tagoshi, H.; Takahashi, H.; Tatsumi, D.; Tsunesada, Y.; TAMA Collaboration
2003-07-01
We implemented and evaluated the Gravitational wave event search in TAMA 300 data analysis. Our searches are for the inspiral gravitational wave from coalescing compact binary, Black Hole (BH) quasi-normal ringing, supernova bursts, and continuous wave from SN1987a remnant. Using TAMA's over 2000 hours of observation data, we have progresses of the searches and improved the upper limits.
Essick, Reed; Vitale, Salvatore; Katsavounidis, Erik; Vedovato, Gabriele; Klimenko, Sergey
2015-02-20
The Laser Interferometer Gravitational wave Observatory (LIGO) and Virgo advanced ground-based gravitational-wave detectors will begin collecting science data in 2015. With first detections expected to follow, it is important to quantify how well generic gravitational-wave transients can be localized on the sky. This is crucial for correctly identifying electromagnetic counterparts as well as understanding gravitational-wave physics and source populations. We present a study of sky localization capabilities for two search and parameter estimation algorithms: coherent WaveBurst, a constrained likelihood algorithm operating in close to real-time, and LALInferenceBurst, a Markov chain Monte Carlo parameter estimation algorithm developed to recover generic transient signals with latency of a few hours. Furthermore, we focus on the first few years of the advanced detector era, when we expect to only have two (2015) and later three (2016) operational detectors, all below design sensitivity. These detector configurations can produce significantly different sky localizations, which we quantify in detail. We observe a clear improvement in localization of the average detected signal when progressing from two-detector to three-detector networks, as expected. Although localization depends on the waveform morphology, approximately 50% of detected signals would be imaged after observing 100-200 deg{sup 2} in 2015 and 60-110 deg{sup 2} in 2016, although knowledge of the waveform can reduce this to as little as 22 deg{sup 2}. This is the first comprehensive study on sky localization capabilities for generic transients of the early network of advanced LIGO and Virgo detectors, including the early LIGO-only two-detector configuration.
NASA Astrophysics Data System (ADS)
Essick, Reed; Vitale, Salvatore; Katsavounidis, Erik; Vedovato, Gabriele; Klimenko, Sergey
2015-02-01
The Laser Interferometer Gravitational wave Observatory (LIGO) and Virgo advanced ground-based gravitational-wave detectors will begin collecting science data in 2015. With first detections expected to follow, it is important to quantify how well generic gravitational-wave transients can be localized on the sky. This is crucial for correctly identifying electromagnetic counterparts as well as understanding gravitational-wave physics and source populations. We present a study of sky localization capabilities for two search and parameter estimation algorithms: coherent WaveBurst, a constrained likelihood algorithm operating in close to real-time, and LALInferenceBurst, a Markov chain Monte Carlo parameter estimation algorithm developed to recover generic transient signals with latency of a few hours. Furthermore, we focus on the first few years of the advanced detector era, when we expect to only have two (2015) and later three (2016) operational detectors, all below design sensitivity. These detector configurations can produce significantly different sky localizations, which we quantify in detail. We observe a clear improvement in localization of the average detected signal when progressing from two-detector to three-detector networks, as expected. Although localization depends on the waveform morphology, approximately 50% of detected signals would be imaged after observing 100-200 deg2 in 2015 and 60-110 deg2 in 2016, although knowledge of the waveform can reduce this to as little as 22 deg2. This is the first comprehensive study on sky localization capabilities for generic transients of the early network of advanced LIGO and Virgo detectors, including the early LIGO-only two-detector configuration.
Biesiada, Marek; Ding, Xuheng; Zhu, Zong-Hong; Piórkowska, Aleksandra E-mail: dingxuheng@mail.bnu.edu.cn E-mail: zhuzh@bnu.edu.cn
2014-10-01
Gravitational wave (GW) experiments are entering their advanced stage which should soon open a new observational window on the Universe. Looking into this future, the Einstein Telescope (ET) was designed to have a fantastic sensitivity improving significantly over the advanced GW detectors. One of the most important astrophysical GW sources supposed to be detected by the ET in large numbers are double compact objects (DCO) and some of such events should be gravitationally lensed by intervening galaxies. We explore the prospects of observing gravitationally lensed inspiral DCO events in the ET. This analysis is a significant extension of our previous paper [1]. We are using the intrinsic merger rates of the whole class of DCO (NS-NS,BH-NS,BH-BH) located at different redshifts as calculated by [2] by using StarTrack population synthesis evolutionary code. We discuss in details predictions from each evolutionary scenario. Our general conclusion is that ET would register about 50–100 strongly lensed inspiral events per year. Only the scenario in which nascent BHs receive strong kick gives the predictions of a few events per year. Such lensed events would be dominated by the BH-BH merging binary systems. Our results suggest that during a few years of successful operation ET will provide a considerable catalog of strongly lensed events.
Tests of Bayesian model selection techniques for gravitational wave astronomy
Cornish, Neil J.; Littenberg, Tyson B.
2007-10-15
The analysis of gravitational wave data involves many model selection problems. The most important example is the detection problem of selecting between the data being consistent with instrument noise alone, or instrument noise and a gravitational wave signal. The analysis of data from ground based gravitational wave detectors is mostly conducted using classical statistics, and methods such as the Neyman-Peterson criteria are used for model selection. Future space based detectors, such as the Laser Interferometer Space Antenna (LISA), are expected to produce rich data streams containing the signals from many millions of sources. Determining the number of sources that are resolvable, and the most appropriate description of each source poses a challenging model selection problem that may best be addressed in a Bayesian framework. An important class of LISA sources are the millions of low-mass binary systems within our own galaxy, tens of thousands of which will be detectable. Not only are the number of sources unknown, but so are the number of parameters required to model the waveforms. For example, a significant subset of the resolvable galactic binaries will exhibit orbital frequency evolution, while a smaller number will have measurable eccentricity. In the Bayesian approach to model selection one needs to compute the Bayes factor between competing models. Here we explore various methods for computing Bayes factors in the context of determining which galactic binaries have measurable frequency evolution. The methods explored include a reverse jump Markov chain Monte Carlo algorithm, Savage-Dickie density ratios, the Schwarz-Bayes information criterion, and the Laplace approximation to the model evidence. We find good agreement between all of the approaches.
Cosmology using advanced gravitational-wave detectors alone
NASA Astrophysics Data System (ADS)
Taylor, Stephen R.; Gair, Jonathan R.; Mandel, Ilya
2012-01-01
We investigate a novel approach to measuring the Hubble constant using gravitational-wave (GW) signals from compact binaries by exploiting the narrowness of the distribution of masses of the underlying neutron-star population. Gravitational-wave observations with a network of detectors will permit a direct, independent measurement of the distance to the source systems. If the redshift of the source is known, these inspiraling double-neutron-star binary systems can be used as standard sirens to extract cosmological information. Unfortunately, the redshift and the system chirp mass are degenerate in GW observations. Thus, most previous work has assumed that the source redshift is obtained from electromagnetic counterparts. However, we investigate a novel method of using these systems as standard sirens with GW observations alone. In this paper, we explore what we can learn about the background cosmology and the mass distribution of neutron stars from the set of neutron-star (NS) mergers detected by such a network. We use a Bayesian formalism to analyze catalogs of NS-NS inspiral detections. We find that it is possible to constrain the Hubble constant, H0, and the parameters of the NS mass function using gravitational-wave data alone, without relying on electromagnetic counterparts. Under reasonable assumptions, we will be able to determine H0 to ±10% using ˜100 observations, provided the Gaussian half-width of the underlying double NS mass distribution is less than 0.04M⊙. The expected precision depends linearly on the intrinsic width of the NS mass function, but has only a weak dependence on H0 near the default parameter values. Finally, we consider what happens if, for some fraction of our data catalog, we have an electromagnetically measured redshift. The detection, and cataloging, of these compact-object mergers will allow precision astronomy, and provide a determination of H0 which is independent of the local distance scale.
NASA Technical Reports Server (NTRS)
Baker, John
2012-01-01
Effects of accretion disks on spins and eccentricities of binaries, and implications for gravitational waves. John Baker Space-based gravitational wave observations will allow exquisitely precise measurements of massive black hole binary properties. Through several recently suggested processes, these properties may depend on interactions with accretion disks through the merger process. I will discuss ways that accretion may influence those binary properties which may be probed by gravitational-wave observations.
Gravitational waves and neutrinos from gamma-ray bursts
Fryer, Christopher Lee
2010-01-01
Gamma-Ray Bursts (GRBs) are not only strong sources of gammaray emission, but also of neutrinos and gravitational waves (GWs). Observat.ions of these particles can provide a good deal of insight into the progenitor and engine behind these outbursts. But to do so, these particles must be detected . Here we review the different phases of GW and neutrino emission from a range of GRB progenitors, outlining the features and detectability of these phases. Unfortunately, except for a few cases, the detection of non-photon emission is very difficult. But the potential gain from any detection make understanding these sources critically important.
Probing the primordial universe with gravitational waves detectors
NASA Astrophysics Data System (ADS)
Wang, Yu-Tong; Cai, Yong; Liu, Zhi-Guo; Piao, Yun-Song
2017-01-01
The spectrum of primordial gravitational waves (GWs), especially its tilt nT, carries significant information about the primordial universe. Combining recent aLIGO and Planck2015+BK14 data, we find that the current limit is nT=0.016+0.614‑0.989 at 95% C.L. We also estimate the impacts of Einstein Telescope and LISA on constraining nT. Moreover, based on the effective field theory of cosmological perturbations, we make an attempt to confront some models of early universe scenarios, which produce blue-tilted GWs spectrum (nT>0), with the corresponding datasets.
Gravitational waves from pulsars with measured braking index
NASA Astrophysics Data System (ADS)
de Araujo, José C. N.; Coelho, Jaziel G.; Costa, Cesar A.
2016-09-01
We study the putative emission of gravitational waves (GWs) in particular for pulsars with measured braking index. We show that the appropriate combination of both GW emission and magnetic dipole brakes can naturally explain the measured braking index, when the surface magnetic field and the angle between the magnetic dipole and rotation axes are time dependent. Then we discuss the detectability of these very pulsars by aLIGO and the Einstein Telescope. We call attention to the realistic possibility that aLIGO can detect the GWs generated by at least some of these pulsars, such as Vela, for example.
Spherical Harmonic Decomposition of Gravitational Waves Across Mesh Refinement Boundaries
NASA Technical Reports Server (NTRS)
Fiske, David R.; Baker, John; vanMeter, James R.; Centrella, Joan M.
2005-01-01
We evolve a linearized (Teukolsky) solution of the Einstein equations with a non-linear Einstein solver. Using this testbed, we are able to show that such gravitational waves, defined by the Weyl scalars in the Newman-Penrose formalism, propagate faithfully across mesh refinement boundaries, and use, for the first time to our knowledge, a novel algorithm due to Misner to compute spherical harmonic components of our waveforms. We show that the algorithm performs extremely well, even when the extraction sphere intersects refinement boundaries.
Adaptive filters for detection of gravitational waves from coalescing binaries
Eleuteri, Antonio; Milano, Leopoldo; De Rosa, Rosario; Garufi, Fabio; Acernese, Fausto; Barone, Fabrizio; Giordano, Lara; Pardi, Silvio
2006-06-15
In this work we propose use of infinite impulse response adaptive line enhancer (IIR ALE) filters for detection of gravitational waves from coalescing binaries. We extend our previous work and define an adaptive matched filter structure. Filter performance is analyzed in terms of the tracking capability and determination of filter parameters. Furthermore, following the Neyman-Pearson strategy, receiver operating characteristics are derived, with closedform expressions for detection threshold, false alarm, and detection probability. Extensive tests demonstrate the effectiveness of adaptive filters both in terms of small computational cost and robustness.
Ultrahigh [ital Q] pendulum suspensions for gravitational wave detectors
Blair, D.G.; Ju, L.; Notcutt, M. )
1993-07-01
Pendulum suspensions for laser interferometer gravitational wave detectors need to have an extremely high [ital Q] factor to minimize Brownian motion noise. In this paper we analyze the limits to the [ital Q] factor of the compound pendulum. We show that the observed acoustic loss of niobium can allow pendulum [ital Q] factors of 10[sup 10] to be achieved. This should enable a 3 km terrestrial laser interferometer detector to achieve strain sensitivity of 10[sup [minus]22]/[radical]Hz at frequencies as low as 10 Hz. At cryogenic temperatures [ital Q] factors up to 10[sup 12] should be achievable.
Gravitational Waves and the Maximum Spin Frequency of Neutron Stars
NASA Astrophysics Data System (ADS)
Patruno, Alessandro; Haskell, Brynmor; D'Angelo, Caroline
2012-02-01
In this paper, we re-examine the idea that gravitational waves are required as a braking mechanism to explain the observed maximum spin frequency of neutron stars. We show that for millisecond X-ray pulsars, the existence of spin equilibrium as set by the disk/magnetosphere interaction is sufficient to explain the observations. We show as well that no clear correlation exists between the neutron star magnetic field B and the X-ray outburst luminosity LX when considering an enlarged sample size of millisecond X-ray pulsars.
GRAVITATIONAL WAVES AND THE MAXIMUM SPIN FREQUENCY OF NEUTRON STARS
Patruno, Alessandro; Haskell, Brynmor; D'Angelo, Caroline
2012-02-10
In this paper, we re-examine the idea that gravitational waves are required as a braking mechanism to explain the observed maximum spin frequency of neutron stars. We show that for millisecond X-ray pulsars, the existence of spin equilibrium as set by the disk/magnetosphere interaction is sufficient to explain the observations. We show as well that no clear correlation exists between the neutron star magnetic field B and the X-ray outburst luminosity L{sub X} when considering an enlarged sample size of millisecond X-ray pulsars.
Directly comparing gravitational wave data to numerical relativity simulations: systematics
NASA Astrophysics Data System (ADS)
Lange, Jacob; O'Shaughnessy, Richard; Healy, James; Lousto, Carlos; Zlochower, Yosef; Shoemaker, Deirdre; Lovelace, Geoffrey; Pankow, Christopher; Brady, Patrick; Scheel, Mark; Pfeiffer, Harald; Ossokine, Serguei
2017-01-01
We compare synthetic data directly to complete numerical relativity simulations of binary black holes. In doing so, we circumvent ad-hoc approximations introduced in semi-analytical models previously used in gravitational wave parameter estimation and compare the data against the most accurate waveforms including higher modes. In this talk, we focus on the synthetic studies that test potential sources of systematic errors. We also run ``end-to-end'' studies of intrinsically different synthetic sources to show we can recover parameters for different systems.
Limits on Anisotropy in the Nanohertz Stochastic Gravitational Wave Background.
Taylor, S R; Mingarelli, C M F; Gair, J R; Sesana, A; Theureau, G; Babak, S; Bassa, C G; Brem, P; Burgay, M; Caballero, R N; Champion, D J; Cognard, I; Desvignes, G; Guillemot, L; Hessels, J W T; Janssen, G H; Karuppusamy, R; Kramer, M; Lassus, A; Lazarus, P; Lentati, L; Liu, K; Osłowski, S; Perrodin, D; Petiteau, A; Possenti, A; Purver, M B; Rosado, P A; Sanidas, S A; Smits, R; Stappers, B; Tiburzi, C; van Haasteren, R; Vecchio, A; Verbiest, J P W
2015-07-24
The paucity of observed supermassive black hole binaries (SMBHBs) may imply that the gravitational wave background (GWB) from this population is anisotropic, rendering existing analyses suboptimal. We present the first constraints on the angular distribution of a nanohertz stochastic GWB from circular, inspiral-driven SMBHBs using the 2015 European Pulsar Timing Array data. Our analysis of the GWB in the ~2-90 nHz band shows consistency with isotropy, with the strain amplitude in l>0 spherical harmonic multipoles ≲40% of the monopole value. We expect that these more general techniques will become standard tools to probe the angular distribution of source populations.
Analysis methods for burst gravitational waves with TAMA data
NASA Astrophysics Data System (ADS)
Ando, Masaki; Arai, K.; Nagano, S.; Takahashi, R.; Sato, S.; Tatsumi, D.; Tsunesada, Y.; Kanda, N.; Kawamura, S.; Beyersdorf, P.; Zhu, Zonh-Hong; Numata, K.; Iida, Y.; Aso, Y.; Mio, N.; Moriwaki, S.; Somiya, K.; Miyoki, S.; Kondo, K.; Takahashi, H.; Hayama, K.; Tagoshi, H.; Fujimoto, M.-K.; Tsubono, K.; Kuroda, K.; TAMA Collaboration
2004-10-01
We describe analysis methods and results for burst gravitational waves with data obtained in the eighth observation run by the TAMA300 detector. In this analysis, we used an excess-power filter for signal detection, and two types of veto for fake-event rejection; one is a time-scale selection of events and the other is a veto with auxiliary information recorded together with the main signal. We generated an event-candidate list with this analysis procedure, which will be used for coincidence analysis with the other detectors.
Numerical study of primordial magnetic field amplification by inflation-produced gravitational waves
Kuroyanagi, Sachiko; Tashiro, Hiroyuki; Sugiyama, Naoshi
2010-01-15
We numerically study the interaction of inflation-produced magnetic fields with gravitational waves, both of which originate from quantum fluctuations during inflation. The resonance between the magnetic field perturbations and the gravitational waves has been suggested as a possible mechanism for magnetic field amplification. However, some analytical studies suggest that the effect of the inflationary gravitational waves is too small to provide significant amplification. Our numerical study shows more clearly how the interaction affects the magnetic fields and confirms the weakness of the influence of the gravitational waves. We present an investigation based on the magnetohydrodynamic approximation and take into account the differences of the Alfven speed.
Distinguishing signal from noise: New techniques for gravitational wave data analysis
NASA Astrophysics Data System (ADS)
Baker, Paul Thomas
The principal problem of gravitational wave detection is distinguishing true gravitational wave signals from non-Gaussian noise artifacts. We describe two methods to deal with the problem of non-Gaussian noise in the Laser Interferometer Gravitational Observatory (LIGO). Perturbed black holes (BH) are known to vibrate at determinable quasi-normal mode frequencies. These vibrational modes are strongly excited during the inspiral and merger of binary BH systems. We will develop a template based search for gravitational waves from black hole ringdowns: the final stage of binary merger. Past searches for gravitational waves developed ad hoc detection statistics in an attempt to separate the expected gravitational wave signals from noise. We show how using the output of a multi-variate statistical classifier trained to directly probe the high dimensional parameter space of gravitational waves can improve a search over more traditional means. We conclude by placing preliminary upper limits on the rate of ringdown producing binary BH mergers. LIGO data contains frequent, non-Gaussian, instrument artifacts or glitches. Current LIGO searches for un-modeled gravitational wave bursts are primarily limited by the presence of glitches in analyzed data. We describe the BayesWave algorithm, wherein we model gravitational wave signals and detector glitches simultaneously in the wavelet domain. Using bayesian model selection techniques and a reversible jump Markov chain Monte Carlo, we are able determine whether data is consistent with the presence of gravitational waves, detector glitches, or both. We demonstrate BayesWave's utility as a data quality tool by fitting glitches non-Gaussian LIGO data. Finally, we discuss how BayesWave can be extended into a full-fledged search for gravitational wave bursts.
Reheating and primordial gravitational waves in generalized Galilean genesis
Nishi, Sakine; Kobayashi, Tsutomu E-mail: tsutomu@rikkyo.ac.jp
2016-04-01
Galilean genesis is an alternative to inflation, in which the universe starts expanding from Minkowski with the stable violation of the null energy condition. In this paper, we discuss how the early universe is reheated through the gravitational particle production at the transition from the genesis phase to the subsequent phase where the kinetic energy of the scalar field is dominant. We then study the consequences of gravitational reheating after Galilean genesis on the spectrum of primordial gravitational waves. The resultant spectrum is strongly blue, and at high frequencies Ω{sub gw}∝ f{sup 3} in terms of the energy density per unit logarithmic frequency. Though this cannot be detected in existing detectors, the amplitude can be as large as Ω{sub gw}∼ 10{sup −12} at f∼ 100 MHz, providing a future test of the genesis scenario. The analysis is performed within the framework of generalized Galilean genesis based on the Horndeski theory, which enables us to derive generic formulas.
Gravitational waves versus X-ray and gamma-ray emission in a short gamma-ray burst
Oliveira, F. G.; Rueda, Jorge A.; Ruffini, R. E-mail: jorge.rueda@icra.it
2014-06-01
Recent progress in the understanding of the physical nature of neutron star equilibrium configurations and the first observational evidence of a genuinely short gamma-ray burst (GRB), GRB 090227B, allows us to give an estimate of the gravitational waves versus the X-ray and gamma-ray emission in a short GRB.
Methodological studies on the search for Gravitational Waves and Neutrinos from Type II Supernovae
NASA Astrophysics Data System (ADS)
Casentini, Claudio
2016-02-01
Type II SNe, also called Core-collapse SuperNovae have a neutrino (v) emission, as confirmed by SN 1987A, and are also potential sources of gravitational waves. Neutrinos and gravitational waves from these sources reach Earth almost contemporaneously and without relevant interaction with stellar matter and interstellar medium. The upcoming advanced gravitational interferometers would be sensitive enough to detect gravitational waves signals from close galactic Core-collapse SuperNovae events. Nevertheless, significant uncertainties on theoretical models of emission remain. A joint search of coincident low energy neutrinos and gravitational waves events from these sources would bring valuable information from the inner core of the collapsing star and would enhance the detection of the so-called Silent SuperNovae. Recently a project for a joint search involving gravitational wave interferometers and neutrino detectors has started. We discuss the benefits of a joint search and the status of the search project.
Parameter estimation in searches for the stochastic gravitational-wave background.
Mandic, V; Thrane, E; Giampanis, S; Regimbau, T
2012-10-26
The stochastic gravitational-wave background (SGWB) is expected to arise from the superposition of many independent and unresolved gravitational-wave signals of either cosmological or astrophysical origin. The spectral content of the SGWB carries signatures of the physics that generated it. We present a Bayesian framework for estimating the parameters associated with different SGWB models using data from gravitational-wave detectors. We apply this technique to recent results from LIGO to produce the first simultaneous 95% confidence level limits on multiple parameters in generic power-law SGWB models and in SGWB models of compact binary coalescences. We also estimate the sensitivity of the upcoming second-generation detectors such as Advanced LIGO or Virgo to these models and demonstrate how SGWB measurements can be combined and compared with observations of individual compact binary coalescences in order to build confidence in the origin of an observed SGWB signal. In doing so, we demonstrate a novel means of differentiating between different sources of the SGWB.
NASA Astrophysics Data System (ADS)
Cook, William G.; Sperhake, Ulrich
2017-02-01
Gravitational waves are one of the most important diagnostic tools in the analysis of strong-gravity dynamics and have been turned into an observational channel with LIGO’s detection of GW150914. Aside from their importance in astrophysics, black holes and compact matter distributions have also assumed a central role in many other branches of physics. These applications often involve spacetimes with D > 4 dimensions where the calculation of gravitational waves is more involved than in the four dimensional case, but has now become possible thanks to substantial progress in the theoretical study of general relativity in D > 4. Here, we develop a numerical implementation of the formalism by Godazgar and Reall [1]—based on projections of the Weyl tensor analogous to the Newman–Penrose scalars—that allows for the calculation of gravitational waves in higher dimensional spacetimes with rotational symmetry. We apply and test this method in black-hole head-on collisions from rest in D = 6 spacetime dimensions and find that a fraction (8.19+/- 0.05)× {{10}-4} of the Arnowitt–Deser–Misner mass is radiated away from the system, in excellent agreement with literature results based on the Kodama–Ishibashi perturbation technique. The method presented here complements the perturbative approach by automatically including contributions from all multipoles rather than computing the energy content of individual multipoles.
SENR, A Super-Efficient Code for Gravitational Wave Source Modeling: Latest Results
NASA Astrophysics Data System (ADS)
Ruchlin, Ian; Etienne, Zachariah; Baumgarte, Thomas
2017-01-01
The science we extract from gravitational wave observations will be limited by our theoretical understanding, so with the recent breakthroughs by LIGO, reliable gravitational wave source modeling has never been more critical. Due to efficiency considerations, current numerical relativity codes are very limited in their applicability to direct LIGO source modeling, so it is important to develop new strategies for making our codes more efficient. We introduce SENR, a Super-Efficient, open-development numerical relativity (NR) code aimed at improving the efficiency of moving-puncture-based LIGO gravitational wave source modeling by 100x. SENR builds upon recent work, in which the BSSN equations are evolved in static spherical coordinates, to allow dynamical coordinates with arbitrary spatial distributions. The physical domain is mapped to a uniform-resolution grid on which derivative operations are approximated using standard central finite difference stencils. The source code is designed to be human-readable, efficient, parallelized, and readily extensible. We present the latest results from the SENR code.
Detectability of bigravity with graviton oscillations using gravitational wave observations
NASA Astrophysics Data System (ADS)
Narikawa, Tatsuya; Ueno, Koh; Tagoshi, Hideyuki; Tanaka, Takahiro; Kanda, Nobuyuki; Nakamura, Takashi
2015-03-01
The gravitational waveforms in the ghost-free bigravity theory exhibit deviations from those in general relativity. The main difference is caused by graviton oscillations in the bigravity theory. We investigate the prospects for the detection of the corrections to gravitational waveforms from coalescing compact binaries due to graviton oscillations and for constraining bigravity parameters with the gravitational wave observations. We consider the bigravity model discussed by the De Felice-Nakamura-Tanaka subset of the bigravity model, and the phenomenological model in which the bigravity parameters are treated as independent variables. In both models, the bigravity waveform shows strong amplitude modulation, and there can be a characteristic frequency of the largest peak of the amplitude, which depends on the bigravity parameters. We show that there is a detectable region of the bigravity parameters for the advanced ground-based laser interferometers, such as Advanced LIGO, Advanced Virgo, and KAGRA. This region corresponds to the effective graviton mass of μ ≳10-17 cm-1 for c ˜ -1 ≳10-19 in the phenomenological model, while μ ≳10-16.5 cm-1 for κ ξc2≳100.5 in the De Felice-Nakamura-Tanaka subset of the bigravity model, respectively, where c ˜ is the propagation speed of the massive graviton and κ ξc2 corresponds to the corrections to the gravitational constant in general relativity. These regions are not excluded by existing solar system tests. We also show that, in the case of 1.4 -1.4 M⊙ binaries at the distance of 200 Mpc, log μ2 is determined with an accuracy of O (0.1 )% at the 1 σ level for a fiducial model with μ2=1 0-33 cm-2 in the case of the phenomenological model.
Gravitational wave polarization modes in f (R ) theories
NASA Astrophysics Data System (ADS)
Kausar, H. Rizwana; Philippoz, Lionel; Jetzer, Philippe
2016-06-01
Many studies have been carried out in the literature to evaluate the number of polarization modes of gravitational waves in modified theories, in particular in f (R ) theories. In the latter ones, besides the usual two transverse-traceless tensor modes present in general relativity, there are two additional scalar ones: a massive longitudinal mode and a massless transverse mode (the so-called breathing mode). This last mode has often been overlooked in the literature, due to the assumption that the application of the Lorenz gauge implies transverse-traceless wave solutions. We however show that this is in general not possible and, in particular, that the traceless condition cannot be imposed due to the fact that we no longer have a Minkowski background metric. Our findings are in agreement with the results found using the Newman-Penrose formalism and thus clarify the inconsistencies found so far in the literature.
Obtaining gravitational waves from inspiral binary systems using LIGO data
NASA Astrophysics Data System (ADS)
Antelis, Javier M.; Moreno, Claudia
2017-01-01
The discovery of the astrophysical events GW150926 and GW151226 has experimentally confirmed the existence of gravitational waves (GW) and has demonstrated the existence of binary stellar-mass black hole systems. This finding marks the beginning of a new era that will reveal unexpected features of our universe. This work presents a basic insight to the fundamental theory of GW emitted by inspiral binary systems and describes the scientific and technological efforts developed to measure these waves using the interferometer-based detector called LIGO. Subsequently, the work presents a comprehensive data analysis methodology based on the matched filter algorithm, which aims to recovery GW signals emitted by inspiral binary systems of astrophysical sources. This algorithm was evaluated with freely available LIGO data containing injected GW waveforms. Results of the experiments performed to assess detection accuracy showed the recovery of 85% of the injected GW.
Explosion mechanism, neutrino burst and gravitational wave in core-collapse supernovae
NASA Astrophysics Data System (ADS)
Kotake, Kei; Sato, Katsuhiko; Takahashi, Keitaro
2006-04-01
Core-collapse supernovae are among the most energetic explosions in the universe marking the catastrophic end of massive stars. In spite of rigorous studies for several decades, we still do not understand the explosion mechanism completely. Since they are related to many astrophysical phenomena such as nucleosynthesis, gamma-ray bursts and acceleration of cosmic rays, understanding of their physics has been of wide interest to the astrophysical community. In this paper, we review recent progress in the study of core-collapse supernovae focusing on the explosion mechanism, supernova neutrinos and the gravitational waves. Regarding the explosion mechanism, we present a review paying particular attention to the roles of multidimensional aspects, such as convection, rotation and magnetic fields, on the neutrino heating mechanism. Next, we discuss supernova neutrino, which is a powerful tool to probe not only deep inside the supernovae but also the intrinsic properties of neutrinos. For this purpose, it is necessary to understand neutrino oscillation which has been established recently by many experiments. Gravitational astronomy is also now becoming a reality. We present an extensive review on the physical foundations and the emission mechanism of gravitational waves in detail and discuss the possibility of their detections.
Physics of Gravitational Interaction: Geometry of Space or Quantum Field in Space
NASA Astrophysics Data System (ADS)
Baryshev, Yurij
2006-03-01
Thirring-Feynman's tensor field approach to gravitation opens new understanding on the physics of gravitational interaction and stimulates novel experiments on the nature of gravity. According to Field Gravity, the universal gravity force is caused by exchange of gravitons - the quanta of gravity field. Energy of this field is well-defined and excludes the singularity. All classical relativistic effects are the same as in General Relativity. The intrinsic scalar (spin 0) part of gravity field corresponds to ``antigravity'' and only together with the pure tensor (spin 2) part gives the usual Newtonian force. Laboratory and astrophysical experiments which may test the predictions of FG, will be performed in near future. In particular, observations at gravity observatories with bar and interferometric detectors, like Explorer, Nautilus, LIGO and VIRGO, will check the predicted scalar gravitational waves from supernova explosions. New types of cosmological models in Minkowski space are possible too.
Probing the size of extra dimensions with gravitational wave astronomy
Yagi, Kent; Tanahashi, Norihiro; Tanaka, Takahiro
2011-04-15
In the Randall-Sundrum II braneworld model, it has been conjectured, according to the AdS/CFT correspondence, that a brane-localized black hole (BH) larger than the bulk AdS curvature scale l cannot be static, and it is dual to a four-dimensional BH emitting Hawking radiation through some quantum fields. In this scenario, the number of the quantum field species is so large that this radiation changes the orbital evolution of a BH binary. We derived the correction to the gravitational waveform phase due to this effect and estimated the upper bounds on l by performing Fisher analyses. We found that the Deci-Hertz Interferometer Gravitational Wave Observatory and the Big Bang Observatory (DECIGO/BBO) can give a stronger constraint than the current tabletop result by detecting gravitational waves from small mass BH/BH and BH/neutron star (NS) binaries. Furthermore, DECIGO/BBO is expected to detect 10{sup 5} BH/NS binaries per year. Taking this advantage, we find that DECIGO/BBO can actually measure l down to l=0.33 {mu}m for a 5 yr observation if we know that binaries are circular a priori. This is about 40 times smaller than the upper bound obtained from the tabletop experiment. On the other hand, when we take eccentricities into binary parameters, the detection limit weakens to l=1.5 {mu}m due to strong degeneracies between l and eccentricities. We also derived the upper bound on l from the expected detection number of extreme mass ratio inspirals with LISA and BH/NS binaries with DECIGO/BBO, extending the discussion made recently by McWilliams [Phys. Rev. Lett. 104, 141601 (2010)]. We found that these less robust constraints are weaker than the ones from phase differences.
A binary population synthesis study on gravitational wave sources
NASA Astrophysics Data System (ADS)
Jinzhong, Liu; Yu, Zhang
Gravitational waves (GW) are a natural consequence of Einstein's theory of gravity (general relativity), and minute distortions of space-time. Gravitational Wave Astronomy is an emerging branch of observational astronomy which aims to use GWs to collect observational data about objects such as neutron stars and black holes, about events such as supernovae and about the early universe shortly after the big bang.This field will evolve to become an established component of 21st century multi-messenger astronomy, and will stand shoulder-to-shoulder with gamma-ray, x-ray, optical, infrared and radio astronomers in exploring the cosmos. In this paper, we state a recent theoretical study on GW sources, and present the results of our studies on the field using a binary population synthesis (BPS) approach, which was designed to investigate the formation of many interesting binary-related objects, including close double white dwarfs, AM CVn stars, ultra-compact X-ray binaries(UCXBs), double neutron stars, double stellar black holes. Here we report how BPS can be used to determine the GW radiation from double compact objects.
Gravitational-wave cosmology across 29 decades in frequency
NASA Astrophysics Data System (ADS)
Mingarelli, Chiara; Lasky, Paul; Smith, Tristan; Giblin, John T.; Thrane, Eric; Reardon, Daniel; Caldwell, Robert; Parkes Pulsar Timing Array Collaboration
2016-03-01
We derive constraints on the spectrum of the primordial gravitational wave background, and hence on theories of the early Universe, by combining experiments that cover 29 orders of magnitude in frequency. These include Planck observations of cosmic microwave background (CMB) temperature and polarization power spectra and lensing, together with baryon acoustic oscillations and big bang nucleosynthesis measurements, and new pulsar timing array and ground-based interferometer limits. The combination of experiments allows us to constrain cosmological parameters, including the inflationary spectral index, nt, and the tensor-to-scalar ratio, r. Results from individual experiments include a stringent nanohertz limit of the primordial background from the Parkes Pulsar Timing Array, Ω(f) < 2 . 3 ×10-10 . Observations of the CMB alone limit the gravitational-wave spectral index at 95% confidence to nt <~ 5 for a tensor-to-scalar ratio of r = 0 . 11 . However, the combination of all the above experiments limits nt < 0 . 36 . Future Advanced LIGO observations are expected to further constrain nt < 0 . 34 by 2020. When CMB experiments detect a non-zero r, our results will imply even more stringent constraints on nt and hence theories of the early Universe. Mingarelli is the 2nd author on the submitted manuscript.
Component separation of a isotropic Gravitational Wave Background
NASA Astrophysics Data System (ADS)
Parida, Abhishek; Mitra, Sanjit; Jhingan, Sanjay
2016-04-01
A Gravitational Wave Background (GWB) is expected in the universe from the superposition of a large number of unresolved astrophysical sources and phenomena in the early universe. Each component of the background (e.g., from primordial metric perturbations, binary neutron stars, milli-second pulsars etc.) has its own spectral shape. Many ongoing experiments aim to probe GWB at a variety of frequency bands. In the last two decades, using data from ground-based laser interferometric gravitational wave (GW) observatories, upper limits on GWB were placed in the frequency range of 0~ 50-100 Hz, considering one spectral shape at a time. However, one strong component can significantly enhance the estimated strength of another component. Hence, estimation of the amplitudes of the components with different spectral shapes should be done jointly. Here we propose a method for "component separation" of a statistically isotropic background, that can, for the first time, jointly estimate the amplitudes of many components and place upper limits. The method is rather straightforward and needs negligible amount of computation. It utilises the linear relationship between the measurements and the amplitudes of the actual components, alleviating the need for a sampling based method, e.g., Markov Chain Monte Carlo (MCMC) or matched filtering, which are computationally intensive and cumbersome in a multi-dimensional parameter space. Using this formalism we could also study how many independent components can be separated using a given dataset from a network of current and upcoming ground based interferometric detectors.
Searches for Continuous Gravitational Waves from Nine Young Supernova Remnants
NASA Astrophysics Data System (ADS)
Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Ain, A.; Ajith, P.; Alemic, A.; Allen, B.; Allocca, A.; Amariutei, D.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Areeda, J. S.; Ast, S.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Aylott, B. E.; Babak, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barbet, M.; Barclay, S.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Bartlett, J.; Barton, M. A.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bauer, Th. S.; Baune, C.; Bavigadda, V.; Behnke, B.; Bejger, M.; Belczynski, C.; Bell, A. S.; Bell, C.; Benacquista, M.; 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.; Biscans, S.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackburn, L.; Blair, C. D.; Blair, D.; Bloemen, S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, G.; Bojtos, P.; Bond, C.; Bondu, F.; Bonelli, L.; Bonnand, R.; Bork, R.; Born, M.; Boschi, V.; Bose, Sukanta; 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.; Brown, N. M.; Buchman, S.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Cadonati, L.; Cagnoli, G.; Calderón Bustillo, J.; Calloni, E.; Camp, J. B.; Cannon, K. C.; Cao, J.; Capano, C. D.; Carbognani, F.; Caride, S.; Caudill, S.; Cavaglià, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C.; Cesarini, E.; Chakraborty, R.; Chalermsongsak, T.; Chamberlin, S. J.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Chen, Y.; 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.; Colombini, M.; Cominsky, L.; Constancio, M., Jr.; Conte, A.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Coulon, J.-P.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cumming, A.; Cunningham, L.; Cuoco, E.; Cutler, C.; Dahl, K.; Dal Canton, T.; Damjanic, M.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dartez, L.; Dattilo, V.; Dave, I.; Daveloza, H.; Davier, M.; Davies, G. S.; Daw, E. J.; Day, R.; DeBra, D.; Debreczeni, G.; Degallaix, J.; De Laurentis, M.; Deléglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Dhurandhar, S.; Díaz, M.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, A.; Dojcinoski, G.; Dolique, V.; Dominguez, E.; Donovan, F.; Dooley, K. L.; Doravari, S.; Douglas, R.; Downes, T. P.; Drago, M.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dwyer, S.; Eberle, T.; Edo, T.; Edwards, M.; Edwards, M.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Essick, R.; Etzel, T.; Evans, M.; Evans, T.; Factourovich, M.; Fafone, V.; Fairhurst, S.; Fan, X.; Fang, Q.; Farinon, S.; Farr, B.; Farr, W. M.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Feldbaum, D.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fisher, R. P.; Flaminio, R.; Fournier, J.-D.; Franco, S.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Fricke, T. T.; Fritschel, P.; Frolov, V. V.; Fuentes-Tapia, S.; Fulda, P.; Fyffe, M.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S.; Garufi, F.; Gatto, A.; Gehrels, N.; Gemme, G.; Gendre, B.; Genin, E.; Gennai, A.; Gergely, L. Á.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gleason, J.; Goetz, E.; Goetz, R.; Gondan, L.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Gossler, S.; Gouaty, R.; Gräf, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guido, C. J.; Guo, X.; Gushwa, K.; Gustafson, E. K.; Gustafson, R.; Hacker, J.; Hall, E. D.; Hammond, G.; Hanke, M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M.; Hartman, M. T.; Haster, C.-J.; Haughian, K.; Heidmann, A.; Heintze, M.; Heinzel, G.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E.; Howell, E. J.; Hu, Y. M.; Huerta, E.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh, M.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Islas, G.; Isler, J. C.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacobson, M.; Jang, H.; Jaranowski, P.; Jawahar, S.; Ji, Y.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; K, Haris; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kéfélian, F.; Keiser, G. M.; Keitel, D.; Kelley, D. B.; Kells, W.; Keppel, D. G.; Key, J. S.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, C.; Kim, K.; Kim, N. G.; Kim, N.; 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.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krishnan, B.; Królak, A.; Krueger, C.; Kuehn, G.; Kumar, A.; Kumar, P.; Kuo, L.; Kutynia, A.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lazzarini, A.; Lazzaro, C.; Lazzaro, C.; Le, J.; Leaci, P.; Leavey, S.; Lebigot, E.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Levine, B.; Lewis, J.; Li, T. G. F.; Libbrecht, K.; Libson, A.; Lin, A. C.; Littenberg, T. B.; Lockerbie, N. A.; Lockett, V.; Logue, J.; Lombardi, A. L.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J.; Lubinski, M. J.; Lück, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macarthur, J.; MacDonald, T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña na-Sandoval, F.; Magee, R.; Mageswaran, M.; Maglione, C.; Mailand, K.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandel, I.; Mandic, V.; Mangano, V.; Mangano, V.; Mansell, G. L.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markosyan, A.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D.; Marx, J. N.; Mason, K.; Masserot, A.; Massinger, T. J.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; Mazzolo, G.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGuire, S. C.; McIntyre, G.; McIver, J.; McLin, K.; McWilliams, S.; Meacher, D.; Meadors, G. D.; Meidam, J.; Meinders, M.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Moggi, A.; Mohan, M.; Mohanty, S. D.; Mohapatra, S. R. P.; Moore, B.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mossavi, K.; Mours, B.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nagy, M. F.; Nardecchia, I.; Nash, T.; Naticchioni, L.; Nayak, R. K.; Necula, V.; Nedkova, K.; Nelemans, G.; Neri, I.; Neri, M.; Newton, G.; Nguyen, T.; Nielsen, A. B.; Nissanke, S.; Nitz, A. H.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Ochsner, E.; O'Dell, J.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oppermann, P.; Oram, R.; O'Reilly, B.; Ortega, W.; O'Shaughnessy, R.; Osthelder, C.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Pai, S.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Papa, M. A.; Paris, H.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patrick, Z.; Pedraza, M.; Pekowsky, L.; Pele, A.; Penn, S.; Perreca, A.; Phelps, M.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poeld, J.; Poggiani, R.; Post, A.; Poteomkin, A.; Powell, J.; Prasad, J.; Predoi, V.; Premachandra, S.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Principe, M.; Privitera, S.; Prix, R.; Prodi, G. A.; Prokhorov, L.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; 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.; Ramirez, K.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Reula, O.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V.; Romano, R.; Romanov, G.; Romie, J. H.; Rosińska, D.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Saleem, M.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J. R.; Sannibale, V.; Santiago-Prieto, I.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R.; Sawadsky, A.; Scheuer, J.; Schilling, R.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Sevigny, A.; Shaddock, D. A.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, A. D.; Simakov, D.; Singer, A.; Singer, L.; Singh, R.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, J. R.; Smith, M. R.; Smith, R. J. E.; Smith-Lefebvre, N. D.; Son, E. J.; Sorazu, B.; Souradeep, T.; Staley, A.; Stebbins, J.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Steplewski, S.; Stevenson, S.; Stone, R.; Strain, K. A.; Straniero, N.; Strigin, S.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sutton, P. J.; Swinkels, B.; Szczepanczyk, M.; Szeifert, G.; Tacca, M.; Talukder, D.; Tanner, D. B.; Tápai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, R.; Tellez, G.; Theeg, T.; Thirugnanasambandam, M. P.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tomlinson, C.; Tonelli, M.; Torres, C. V.; Torrie, C. I.; Travasso, F.; Traylor, G.; Tse, M.; Tshilumba, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Vajente, G.; Valdes, G.; Vallisneri, M.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; van den Broeck, C.; van der Sluys, M. V.; van Heijningen, J.; van Veggel, A. A.; Vass, S.; Vasúth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, H.; Wang, M.; Wang, X.; 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.; Wilkinson, C.; Williams, L.; Williams, R.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Worden, J.; Xie, S.; Yablon, J.; Yakushin, I.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yang, Q.; Yvert, M.; Zadrożny, A.; Zanolin, M.; Zendri, J.-P.; Zhang, Fan; Zhang, L.; Zhang, M.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhu, X. J.; Zucker, M. E.; Zuraw, S.; Zweizig, J.
2015-11-01
We describe directed searches for continuous gravitational waves (GWs) in data from the sixth Laser Interferometer Gravitational-wave Observatory (LIGO) science data run. The targets were nine young supernova remnants not associated with pulsars; eight of the remnants are associated with non-pulsing suspected neutron stars. One target's parameters are uncertain enough to warrant two searches, for a total of 10. Each search covered a broad band of frequencies and first and second frequency derivatives for a fixed sky direction. The searches coherently integrated data from the two LIGO interferometers over time spans from 5.3-25.3 days using the matched-filtering {F}-statistic. We found no evidence of GW signals. We set 95% confidence upper limits as strong (low) as 4 × 10-25 on intrinsic strain, 2 × 10-7 on fiducial ellipticity, and 4 × 10-5 on r-mode amplitude. These beat the indirect limits from energy conservation and are within the range of theoretical predictions for neutron-star ellipticities and r-mode amplitudes.
MHz gravitational wave constraints with decameter Michelson interferometers
NASA Astrophysics Data System (ADS)
Chou, Aaron S.; Gustafson, Richard; Hogan, Craig; Kamai, Brittany; Kwon, Ohkyung; Lanza, Robert; Larson, Shane L.; McCuller, Lee; Meyer, Stephan S.; Richardson, Jonathan; Stoughton, Chris; Tomlin, Raymond; Weiss, Rainer; Holometer Collaboration
2017-03-01
A new detector, the Fermilab Holometer, consists of separate yet identical 39-meter Michelson interferometers. Strain sensitivity achieved is better than 10-21/√{Hz } between 1 to 13 MHz from a 130-h data set. This measurement exceeds the sensitivity and frequency range made from previous high frequency gravitational wave experiments by many orders of magnitude. Constraints are placed on a stochastic background at 382 Hz resolution. The 3 σ upper limit on ΩGW, the gravitational wave energy density normalized to the closure density, ranges from 5.6 ×1 012 at 1 MHz to 8.4 ×1 015 at 13 MHz. Another result from the same data set is a search for nearby primordial black hole binaries (PBHB). There are no detectable monochromatic PBHBs in the mass range 0.83 - 3.5 ×1 021 g between the Earth and the Moon. Projections for a chirp search with the same data set increase the mass range to 0.59 -2.5 ×1 025 g and distances out to Jupiter. This result presents a new method for placing limits on a poorly constrained mass range of primordial black holes. Additionally, solar system searches for PBHBs place limits on their contribution to the total dark matter fraction.
Telescopes for a Space-Based Gravitational Wave Observatory
NASA Astrophysics Data System (ADS)
Sankar, Shannon; Livas, Jeffrey
2017-01-01
Telescopes are an important part of the science measurement for a space-based gravitational wave observatory. The telescopes should not introduce excess phase noise which might lower the signal-to-noise of the gravitational wave signal. This requirement constrains both the telescope stability and the phase noise due to scattered light. The photoreceiver senses a combination of a local beam, the received beam and scattered light. If the scattered light has significant spatial overlap, and if there is displacement noise in the scatter path, the signal-to-noise of the main measurement can be impacted. We will discuss our approach to addressing this concern. We model the scattered power from the telescope under expected conditions and use these models for evaluating potential telescope designs. We also determine allowable mirror surface roughness and contamination levels from the scattered light models. We implement the best designs by fabricating a series of prototype telescopes of increasing flight readiness, using eLISA as a reference mission for design specifications. Finally, we perform laboratory tests of the fabricated prototype telescope to validate the models and inform our understanding of the eventual flight telescopes.
Gravitational waves from bubble collisions: An analytic derivation
NASA Astrophysics Data System (ADS)
Jinno, Ryusuke; Takimoto, Masahiro
2017-01-01
We consider gravitational wave production by bubble collisions during a cosmological first-order phase transition. In the literature, such spectra have been estimated by simulating the bubble dynamics, under so-called thin-wall and envelope approximations in a flat background metric. However, we show that, within these assumptions, the gravitational wave spectrum can be estimated in an analytic way. Our estimation is based on the observation that the two-point correlator of the energy-momentum tensor ⟨T (x )T (y )⟩ can be expressed analytically under these assumptions. Though the final expressions for the spectrum contain a few integrations that cannot be calculated explicitly, we can easily estimate it numerically. As a result, it is found that the most of the contributions to the spectrum come from single-bubble contribution to the correlator, and in addition the fall-off of the spectrum at high frequencies is found to be proportional to f-1 . We also provide fitting formulas for the spectrum.
Binary Black Hole Mergers, Gravitational Waves, and LISA
NASA Astrophysics Data System (ADS)
Centrella, Joan; Baker, J.; Boggs, W.; Kelly, B.; McWilliams, S.; van Meter, J.
2007-12-01
The final merger of comparable mass binary black holes is expected to be the strongest source of gravitational waves for LISA. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. We will present the results of new simulations of black hole mergers with unequal masses and spins, focusing on the gravitational waves emitted and the accompanying astrophysical "kicks.” The magnitude of these kicks has bearing on the production and growth of supermassive blackholes during the epoch of structure formation, and on the retention of black holes in stellar clusters. This work was supported by NASA grant 06-BEFS06-19, and the simulations were carried out using Project Columbia at the NASA Advanced Supercomputing Division (Ames Research Center) and at the NASA Center for Computational Sciences (Goddard Space Flight Center).
Binary Black Holes, Gravitational Waves, and Numerical Relativity
NASA Technical Reports Server (NTRS)
Centrella, Joan
2006-01-01
The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. This situation has changed dramatically in the past year, with a series of amazing breakthroughs. This talk will take you on this quest for the holy grail of numerical relativity, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LISA and LIGO.
Constraint likelihood analysis for a network of gravitational wave detectors
Klimenko, S.; Rakhmanov, M.; Mitselmakher, G.; Mohanty, S.
2005-12-15
We propose a coherent method for detection and reconstruction of gravitational wave signals with a network of interferometric detectors. The method is derived by using the likelihood ratio functional for unknown signal waveforms. In the likelihood analysis, the global maximum of the likelihood ratio over the space of waveforms is used as the detection statistic. We identify a problem with this approach. In the case of an aligned pair of detectors, the detection statistic depends on the cross correlation between the detectors as expected, but this dependence disappears even for infinitesimally small misalignments. We solve the problem by applying constraints on the likelihood functional and obtain a new class of statistics. The resulting method can be applied to data from a network consisting of any number of detectors with arbitrary detector orientations. The method allows us reconstruction of the source coordinates and the waveforms of two polarization components of a gravitational wave. We study the performance of the method with numerical simulations and find the reconstruction of the source coordinates to be more accurate than in the standard likelihood method.
Optical motion sensor for resonant-bar gravitational wave antennas.
Richard, J P; Pang, Y; Hamilton, J J
1992-04-01
An experiment is described in which an optical method was used to measure fluctuations in the separation between two mirrors of a Fabry-Perot sensor cavity. Noise measurements were made to determine the sensitivity of this device to vibration amplitudes in the frequency range 1.1-2.1 kHz, which is of interestfor resonant-bar gravitational wave antennas. The rms spectral noise density for length fluctuations inthis range was 3.7 x 10(15-) m/Hz((1/2)) and can be related to electronic noise of the circuitry plus vibrationalnoise from the environment. The cavity finesse was relatively low at 117, and the power dissipated in the mirrors was estimated to be 1.9 muW. On a multimode gravitational wave detector, the sensor cavity would be formed by one reference mirror and by one mirror mounted on the last resonator. For a 1200-kg bar, 1.2-g last resonator system operating at 1600 Hz, the sensor described here would exhibit a noise temperature of 18 muK; the resolution in h in the case of negligible thermal noise from the mechanical system would be 3.7 x 10(-18)/Hz((1/2)). Improvements in the sensitivity in a quiet antenna-like environment should be possible with higher finesse mirrors.
Imprints of relic gravitational waves on pulsar timing
NASA Astrophysics Data System (ADS)
Tong, Ming-Lei; Ding, Yong-Heng; Zhao, Cheng-Shi; Gao, Feng; Yan, Bao-Rong; Yang, Ting-Gao; Gao, Yu-Ping
2016-03-01
Relic gravitational waves (RGWs), a background originating during inflation, would leave imprints on pulsar timing residuals. This makes RGWs an important source for detection of RGWs using the method of pulsar timing. In this paper, we discuss the effects of RGWs on single pulsar timing, and quantitatively analyze the timing residuals caused by RGWs with different model parameters. In principle, if the RGWs are strong enough today, they can be detected by timing a single millisecond pulsar with high precision after the intrinsic red noises in pulsar timing residuals are understood, even though simultaneously observing multiple millisecond pulsars is a more powerful technique for extracting gravitational wave signals. We correct the normalization of RGWs using observations of the cosmic microwave background (CMB), which leads to the amplitudes of RGWs being reduced by two orders of magnitude or so compared to our previous works. We obtained new constraints on RGWs using recent observations from the Parkes Pulsar Timing Array, employing the tensor-to-scalar ratio r = 0.2 due to the tensor-type polarization observations of CMB by BICEP2 as a reference value, even though its reliability has been brought into question. Moreover, the constraints on RGWs from CMB and Big Bang nucleosynthesis will also be discussed for comparison.
Evolution of cosmological gravitational waves in f(R) gravity
Ananda, K. N.; Carloni, S.; Dunsby, P. K. S.
2008-01-15
We give a rigorous and mathematically clear presentation of the covariant and gauge-invariant theory of gravitational waves in a perturbed Friedmann-Lemaitre-Robertson-Walker universe for fourth order gravity, where the matter is described by a perfect fluid with a barotropic equation of state. As an example of a consistent analysis of tensor perturbations in fourth order gravity, we apply the formalism to a simple background solution of R{sup n} gravity. We obtain the exact solutions of the perturbation equations for scales much bigger than and smaller than the Hubble radius. It is shown that the evolution of tensor modes is highly sensitive to the choice of n and an interesting new feature arises. During the radiation dominated era, their exists a growing tensor perturbation for nearly all choices of n. This occurs even when the background model is undergoing accelerated expansion as opposed to the case of general relativity. Consequently, cosmological gravitational wave modes can in principle provide a strong constraint on the theory of gravity independent of other cosmological data sets.
Fermi GBM Counterparts to LIGO Gravitational-Wave Candidates
NASA Astrophysics Data System (ADS)
Burns, Eric; Blackburn, Lindy; Briggs, Michael Stephen; Camp, Jordan; Christensen, Nelson; Connaughton, Valerie; Goldstein, Adam; Littenberg, Tyson; Racusin, Judith L.; Shawhan, Peter S.; Pound Singer, Leo; Veitch, John; Zhang, Binbin
2016-04-01
As the advanced configuration of the Laser Interferometer Gravitational-wave Observatory has begun operations, we eagerly anticipate the detection of gravitational waves (GW) with LIGO in coincidence with a gamma-ray signal from the Fermi Gamma-ray Burst Monitor (GBM). The most likely source is a short Gamma-Ray Burst (GRB) arising from the merger of two compact objects. With its broad sky coverage, GBM triggers and localizes more short GRBs than other active space missions, ~40 each year. Combining GBM and LIGO localization uncertainty regions may provide a smaller target to look for the GW host. A joint GBM-LIGO detection increases the confidence in the GW detection and helps characterize the parameters of the merger. Offline searches for weak GRBs that fail to trigger onboard Fermi indicate that additional short GRBs can be detected in the GBM data. I will discuss the implementation and expected benefits of joint searches to detect and localize GW candidates. I will also explore how the non-detection in the GBM data of a signal consistent with GW candidates in the LIGO data can affect follow-up strategies for counterpart searches by other observers.
Astrophysics to z approx. 10 with Gravitational Waves
NASA Technical Reports Server (NTRS)
Stebbins, Robin; Hughes, Scott; Lang, Ryan
2007-01-01
The most useful characterization of a gravitational wave detector's performance is the accuracy with which astrophysical parameters of potential gravitational wave sources can be estimated. One of the most important source types for the Laser Interferometer Space Antenna (LISA) is inspiraling binaries of black holes. LISA can measure mass and spin to better than 1% for a wide range of masses, even out to high redshifts. The most difficult parameter to estimate accurately is almost always luminosity distance. Nonetheless, LISA can measure luminosity distance of intermediate-mass black hole binary systems (total mass approx.10(exp 4) solar mass) out to z approx.10 with distance accuracies approaching 25% in many cases. With this performance, LISA will be able to follow the merger history of black holes from the earliest mergers of proto-galaxies to the present. LISA's performance as a function of mass from 1 to 10(exp 7) solar mass and of redshift out to z approx. 30 will be described. The re-formulation of LISA's science requirements based on an instrument sensitivity model and parameter estimation will be described.
Gravitational waves from the remnants of the first stars
NASA Astrophysics Data System (ADS)
Hartwig, Tilman; Volonteri, Marta; Bromm, Volker; Klessen, Ralf S.; Barausse, Enrico; Magg, Mattis; Stacy, Athena
2016-07-01
Gravitational waves (GWs) provide a revolutionary tool to investigate yet unobserved astrophysical objects. Especially the first stars, which are believed to be more massive than present-day stars, might be indirectly observable via the merger of their compact remnants. We develop a self-consistent, cosmologically representative, semi-analytical model to simulate the formation of the first stars. By extrapolating binary stellar-evolution models at 10 per cent solar metallicity to metal-free stars, we track the individual systems until the coalescence of the compact remnants. We estimate the contribution of primordial stars to the merger rate density and to the detection rate of the Advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO). Owing to their higher masses, the remnants of primordial stars produce strong GW signals, even if their contribution in number is relatively small. We find a probability of ≳1 per cent that the current detection GW150914 is of primordial origin. We estimate that aLIGO will detect roughly 1 primordial BH-BH merger per year for the final design sensitivity, although this rate depends sensitively on the primordial initial mass function (IMF). Turning this around, the detection of black hole mergers with a total binary mass of ˜ 300 M⊙ would enable us to constrain the primordial IMF.
High-Q superconducting niobium cavities for gravitational wave detectors
NASA Astrophysics Data System (ADS)
de Paula, L. A. N.; Furtado, S. R.; Aguiar, O. D.; Oliveira, N. F., Jr.; Castro, P. J.; Barroso, J. J.
2014-10-01
The main purpose of this work is to optimize the electric Q-factor of superconducting niobium klystron cavities to be used in parametric transducers of the Mario Schenberg gravitational wave detector. Many cavities were manufactured from niobium with relatively high tantalum impurities (1420 ppm) and they were cryogenically tested to determine their resonance frequencies, unloaded electrical quality factors (Q0) and electromagnetic couplings. These cavities were closed with a flat niobium plate with tantalum impurities below 1000 ppm and an unloaded electrical quality factors of the order of 105 have been obtained. AC conductivity of the order of 1012 S/m has been found for niobium cavities when matching experimental results with computational simulations. These values for the Q-factor would allow the detector to reach the quantum limit of sensitivity of ~ 10-22 Hz-1/2 in the near future, making it possible to search for gravitational waves around 3.2 kHz. The experimental tests were performed at the laboratories of the National Institute for Space Research (INPE) and at the Institute for Advanced Studies (IEAv - CTA).
Optical motion sensor for resonant-bar gravitational wave antennas
NASA Technical Reports Server (NTRS)
Richard, J.-P.; Pang, Y.; Hamilton, J. J.
1992-01-01
An experiment is described in which an optical method was used to measure fluctuations in the separation between two mirrors of a Fabry-Perot sensor cavity. Noise measurements were made to determine the sensitivity of this device to vibration amplitudes in the frequency range 1.1-2.1 kHz, which is of interest for resonant-bar gravitational wave antennas. The rms spectral noise density for length fluctuations in this range was sq rt 3.7 x 10 exp -15 m/Hz and can be related to electronic noise of the circuitry plus vibrational noise from the environment. The cavity finesse was relatively low at 117, and the power dissipated in the mirrors was estimated to be 1.9 micro-W. On a multimode gravitational wave detector, the sensor cavity would be formed by one reference mirror and by one mirror mounted on the last resonator. For a 1200-kg bar, 1.2-g last resonator system operating at 1600 Hz the sensor described here would exhibit a noise temperature of 18 micro-K; the resolution in h in the case of negligible thermal noise from the mechanical system would be sq rt 3.7 x 10 exp -18/Hz. Improvements in the sensitivity in a quiet antenna-like environment should be possible with higher finesse mirrors.
A Dynamical Gravitational Wave Source in a Dense Cluster
NASA Astrophysics Data System (ADS)
Hurley, Jarrod R.; Sippel, Anna C.; Tout, Christopher A.; Aarseth, Sverre J.
2016-08-01
Making use of a new N-body model to describe the evolution of a moderate-size globular cluster, we investigate the characteristics of the population of black holes within such a cluster. This model reaches core-collapse and achieves a peak central density typical of the dense globular clusters of the Milky Way. Within this high-density environment, we see direct confirmation of the merging of two stellar remnant black holes in a dynamically formed binary, a gravitational wave source. We describe how the formation, evolution, and ultimate ejection/destruction of binary systems containing black holes impacts the evolution of the cluster core. Also, through comparison with previous models of lower density, we show that the period distribution of black hole binaries formed through dynamical interactions in this high-density model favours the production of gravitational wave sources. We confirm that the number of black holes remaining in a star cluster at late times and the characteristics of the binary black hole population depend on the nature of the star cluster, critically on the number density of stars and by extension the relaxation timescale.
Component separation of a isotropic Gravitational Wave Background
Parida, Abhishek; Jhingan, Sanjay; Mitra, Sanjit E-mail: sanjit@iucaa.in
2016-04-01
A Gravitational Wave Background (GWB) is expected in the universe from the superposition of a large number of unresolved astrophysical sources and phenomena in the early universe. Each component of the background (e.g., from primordial metric perturbations, binary neutron stars, milli-second pulsars etc.) has its own spectral shape. Many ongoing experiments aim to probe GWB at a variety of frequency bands. In the last two decades, using data from ground-based laser interferometric gravitational wave (GW) observatories, upper limits on GWB were placed in the frequency range of 0∼ 50−100 Hz, considering one spectral shape at a time. However, one strong component can significantly enhance the estimated strength of another component. Hence, estimation of the amplitudes of the components with different spectral shapes should be done jointly. Here we propose a method for 'component separation' of a statistically isotropic background, that can, for the first time, jointly estimate the amplitudes of many components and place upper limits. The method is rather straightforward and needs negligible amount of computation. It utilises the linear relationship between the measurements and the amplitudes of the actual components, alleviating the need for a sampling based method, e.g., Markov Chain Monte Carlo (MCMC) or matched filtering, which are computationally intensive and cumbersome in a multi-dimensional parameter space. Using this formalism we could also study how many independent components can be separated using a given dataset from a network of current and upcoming ground based interferometric detectors.
Characterization of a Precision Pulsar Timing Gravitational Wave Detector
NASA Astrophysics Data System (ADS)
Lam, Michael T.
2017-01-01
We aim to construct a Galactic-scale detector comprised of an array of pulsars distributed across the sky in an effort to detect low-frequency (nanohertz) gravitational waves. Even without a detection, observations of pulsar timing arrays have allowed us to begin to place impactful astrophysical constraints on dynamical processes occurring during galaxy mergers. Understanding the detector is necessary for improving our sensitivity to gravitational waves and making a detection. Therefore, our goal is to characterize the entire propagation path through the pulsar timing array detector. To do so, we must understand: what intrinsic noise processes occur at the pulsar, what effects the interstellar medium has on pulsed radio emission, and what errors we introduce when measuring the incident electromagnetic radiation at our observatories.In this work, we observed of one of the most spin-stable objects known for 24 hours to understand the fundamental limits of precision pulsar timing. We investigated the effect of non-simultaneous, multi-frequency sampling of pulsar dispersion measures on timing and analyzed the cause of deterministic and stochastic temporal variations seen in dispersion measure time series. We analyzed errors in pulse arrival times and determined the white noise budget for pulsars on the timescale of a single observation. Finally, we measured the excess noise beyond the white noise model in pulsar timing residuals and incorporated our results into a global model over all pulsar populations to improve excess noise scaling relations.
LISA Framework for Enhancing Gravitational Wave Signal Extraction Techniques
NASA Technical Reports Server (NTRS)
Thompson, David E.; Thirumalainambi, Rajkumar
2006-01-01
This paper describes the development of a Framework for benchmarking and comparing signal-extraction and noise-interference-removal methods that are applicable to interferometric Gravitational Wave detector systems. The primary use is towards comparing signal and noise extraction techniques at LISA frequencies from multiple (possibly confused) ,gravitational wave sources. The Framework includes extensive hybrid learning/classification algorithms, as well as post-processing regularization methods, and is based on a unique plug-and-play (component) architecture. Published methods for signal extraction and interference removal at LISA Frequencies are being encoded, as well as multiple source noise models, so that the stiffness of GW Sensitivity Space can be explored under each combination of methods. Furthermore, synthetic datasets and source models can be created and imported into the Framework, and specific degraded numerical experiments can be run to test the flexibility of the analysis methods. The Framework also supports use of full current LISA Testbeds, Synthetic data systems, and Simulators already in existence through plug-ins and wrappers, thus preserving those legacy codes and systems in tact. Because of the component-based architecture, all selected procedures can be registered or de-registered at run-time, and are completely reusable, reconfigurable, and modular.
Binary Black Hole Mergers, Gravitational Waves, and LISA
NASA Technical Reports Server (NTRS)
Centrella, Joan; Baker, J.; Boggs, W.; Kelly, B.; McWilliams, S.; vanMeter, J.
2008-01-01
The final merger of comparable mass binary black holes is expected to be the strongest source of gravitational waves for LISA. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. We will present the results of new simulations of black hole mergers with unequal masses and spins, focusing on the gravitational waves emitted and the accompanying astrophysical "kicks." The magnitude of these kicks has bearing on the production and growth of supermassive black holes during the epoch of structure formation, and on the retention of black holes in stellar clusters.
Difficult Requirements for a Gravitational Wave Mission using Atom Interferometry
NASA Astrophysics Data System (ADS)
Bender, Peter L.
2014-03-01
A PRL paper by Graham, Hogan, Kasevich, and Rajendran in April, 2013 suggested gravitational wave observations in space using single photon transitions on highly forbidden optical lines for atom interferometry measurements. The main example given was based on use of the 698 nm optical clock transition in Sr-87, a 1000 km baseline, and large momentum transfer laser pulse sequences producing 2400 state transitions for a given atom over a 100 s observation period. A specific scenario for such a mission is needed in order to permit evaluation of the requirements. As a stop-gap, a laser power of 30 W, square laser pulses, 1 m diam. transmitting telescopes, and operation of 4 concurrent pairs of atom interferometers are being assumed. Based on these assumptions, the atom cloud temperature requirement would be below 0.1 pK, and the number of atoms required per cloud would be extremely high. Such a mission would be much more complex than a laser interferometry mission with better overall sensitivity, such as the extensively studied LISA mission or the recently proposed evolved-LISA (eLISA) mission. A LISA Pathfinder mission is scheduled for launch in 2015, funded mainly by ESA . A gravitational wave observation theme is being considered by ESA as part of their Cosmic Vision Programme.
Gravitational Wave Detection by Laser Interferometry on Earth
NASA Astrophysics Data System (ADS)
Ruediger, Albrecht
2003-07-01
The existence of gravitational waves is the most prominent of Einstein's predictions that has not yet been directly verified. Worldwide, ground-based gravitational wave detectors using laser interferometry are being commissioned for science runs. The largest are the two US detectors of the LIGO project: facilities at widely separated sites in the states of Washington and Louisiana, each with 4 km armlength. LIGO data runs have shown the excellent reliability. Similarly encouraging results are reported from the British-German project GEO 600 with 600 m arms. The Japanese project TAMA 300 (with 300 m arms) was the earliest to exhibit good and reliable continuous runs. In all of these projects, the final level of sensitivity has yet to be attained. The French-Italian VIRGO project is to start using its 3 km interferometer by the end of this year. Future enhanced versions are being planned, with scientific data not expected until 2008. The sensitivities to be obtained will allow cosmic events of great scientific interest to be monitored. Detection of the events, and the quantitative analysis together with the location in the sky will provide vital information not obtainable via the window of electromagnetic radiation.
Possible Space-Based Gravitational-Wave Observatory Mission Concept
NASA Technical Reports Server (NTRS)
Livas, Jeffrey C.
2015-01-01
The existence of gravitational waves was established by the discovery of the Binary Pulsar PSR 1913+16 by Hulse and Taylor in 1974, for which they were awarded the 1983 Nobel Prize. However, it is the exploitation of these gravitational waves for the extraction of the astrophysical parameters of the sources that will open the first new astronomical window since the development of gamma ray telescopes in the 1970's and enable a new era of discovery and understanding of the Universe. Direct detection is expected in at least two frequency bands from the ground before the end of the decade with Advanced LIGO and Pulsar Timing Arrays. However, many of the most exciting sources will be continuously observable in the band from 0.1-100 mHz, accessible only from space due to seismic noise and gravity gradients in that band that disturb groundbased observatories. This talk will discuss a possible mission concept developed from the original Laser Interferometer Space Antenna (LISA) reference mission but updated to reduce risk and cost.
Gravitational waves and the deformation of compact objects: Topics in relativistic astrophysics
NASA Astrophysics Data System (ADS)
Johnson-McDaniel, Nathan Kieran
In this dissertation, we present various theoretical investigations of sources of gravitational waves, relevant to interpreting the data from current and planned gravitational wave detectors; an idee fixe is the deformation of compact objects. We begin in the strong field, vacuum regime, with a construction of initial data for the numerical simulation of black hole binaries (specializing to the case of nonspinning holes in a quasicircular orbit). The data we construct contain more of the binary's expected physics than any other current data set. In particular, they contain both the binary's outgoing radiation and the expected tidal deformations of the holes. Such improved initial data will likely be necessary for simulations to achieve the accuracy required to supply advanced gravitational wave detectors with templates for parameter estimation. We end in the weak field, hydrodynamic regime with a calculation of the expected accuracy with which one can combine standard electromagnetic and gravitational wave observations of white dwarf binaries to measure the masses of the binary's components. In particular, we show that this measurement will not be contaminated by finite size effects for realistic sources observed by LISA, though such effects could be important for exceptional sources and/or advanced mHz gravitational wave detectors. In the middle, we make a detour into the messy and poorly constrained realm of the physics of neutron star interiors, calculating the shear modulus of hadron--quark mixed phase in hybrid stars. Here we include a rough treatment of charge screening, dimensional continuation of the lattice, and the contributions from changing the cell volume when shearing lowerdimensional lattices. We find that the last of these contributions is necessary to stabilize the lattice for those dimensions, where it makes a considerable contribution to the shear modulus. We then move back to sounder theoretical footing in making a general relativistic
An upper bound from helioseismology on the stochastic background of gravitational waves
Siegel, Daniel M.; Roth, Markus
2014-04-01
The universe is expected to be permeated by a stochastic background of gravitational radiation of astrophysical and cosmological origin. This background is capable of exciting oscillations in solar-like stars. Here we show that solar-like oscillators can be employed as giant hydrodynamical detectors for such a background in the μHz to mHz frequency range, which has remained essentially unexplored until today. We demonstrate this approach by using high-precision radial velocity data for the Sun to constrain the normalized energy density of the stochastic gravitational-wave background around 0.11 mHz. These results open up the possibility for asteroseismic missions like CoRoT and Kepler to probe fundamental physics.
Gravitational Wave Signals from 2D and 3D Core Collapse Supernova Explosions
NASA Astrophysics Data System (ADS)
Yakunin, Konstantin; Mezzacappa, Anthony; Marronetti, Pedro; Bruenn, Stephen; Hix, W. Raphael; Lentz, Eric J.; Messer, O. E. Bronson; Harris, J. Austin; Endeve, Eirik; Blondin, John
2016-03-01
We study two- and three-dimensional (2D and 3D) core-collapse supernovae (CCSN) using our first-principles CCSN simulations performed with the neutrino hydrodynamics code CHIMERA. The following physics is included: Newtonian hydrodynamics with a nuclear equation of state capable of describing matter in both NSE and non-NSE, MGFLD neutrino transport with realistic neutrino interactions, an effective GR gravitational potential, and a nuclear reaction network. Both our 2D and 3D models achieve explosion, which in turn enables us to determine their complete gravitational wave signals. In this talk, we present them, and we analyze the similarities and differences between the 2D and 3D signals.
Wired by Weber - The story of the first searcher and searches for gravitational waves
NASA Astrophysics Data System (ADS)
Trimble, Virginia
2017-02-01
Joseph Weber started thinking about possibilities for detecting gravitational waves or radiation in about 1955. He designed, built, and operated the first detectors, from 1965 until his death in 2000. This paper includes discussions of his life, earlier work on chemical kinetics and what is now called quantum electronics, his published papers, pioneering work on gravitational waves, and its aftermath, both scientific and personal.
Mirrors used in the LIGO interferometers for first detection of gravitational waves.
Pinard, L; Michel, C; Sassolas, B; Balzarini, L; Degallaix, J; Dolique, V; Flaminio, R; Forest, D; Granata, M; Lagrange, B; Straniero, N; Teillon, J; Cagnoli, G
2017-02-01
For the first time, direct detection of gravitational waves occurred in the Laser Interferometer Gravitational-wave Observatory (LIGO) interferometers. These advanced detectors require large fused silica mirrors with optical and mechanical properties and have never been reached until now. This paper details the main achievements of these ion beam sputtering coatings.
Non-Radial Oscillations of Neutron Stars and the Detection of Gravitational Waves
NASA Astrophysics Data System (ADS)
Chirenti, Cecilia; Silveira, Patrick R.; Aguiar, Odylio D.
We study the non-radial oscillations of relativistic neutron stars, in particular the (fundamental) f-modes, which are believed to be the most relevant for the gravitational wave emission of perturbed isolated stars. The expected frequencies of the f-modes are compared to the sensitivity range of Mario Schenberg, the Brazilian gravitational wave spherical detector.
A computational test facility for distributed analysis of gravitational wave signals
NASA Astrophysics Data System (ADS)
Amico, P.; Bosi, L.; Cattuto, C.; Gammaitoni, L.; Punturo, M.; Travasso, F.; Vocca, H.
2004-03-01
In the gravitational wave detector Virgo, the in-time detection of a gravitational wave signal from a coalescing binary stellar system is an intensive computational task. A parallel computing scheme using the message passing interface (MPI) is described. Performance results on a small-scale cluster are reported.
Arzoumanian, Z.; Brazier, A.; Chatterjee, S.; Cordes, J. M.; Dolch, T.; Lam, M. T.; Burke-Spolaor, S.; Chamberlin, S. J.; Ellis, J. A.; Demorest, P. B.; Deng, X.; Koop, M.; Ferdman, R. D.; Kaspi, V. M.; Garver-Daniels, N.; Lorimer, D. R.; Jenet, F.; Jones, G.; Lazio, T. J. W.; Lommen, A. N.; Collaboration: NANOGrav Collaboration; and others
2014-10-20
We perform a search for continuous gravitational waves from individual supermassive black hole binaries using robust frequentist and Bayesian techniques. We augment standard pulsar timing models with the addition of time-variable dispersion measure and frequency variable pulse shape terms. We apply our techniques to the Five Year Data Release from the North American Nanohertz Observatory for Gravitational Waves. We find that there is no evidence for the presence of a detectable continuous gravitational wave; however, we can use these data to place the most constraining upper limits to date on the strength of such gravitational waves. Using the full 17 pulsar data set we place a 95% upper limit on the strain amplitude of h {sub 0} ≲ 3.0 × 10{sup –14} at a frequency of 10 nHz. Furthermore, we place 95% sky-averaged lower limits on the luminosity distance to such gravitational wave sources, finding that d{sub L} ≳ 425 Mpc for sources at a frequency of 10 nHz and chirp mass 10{sup 10} M {sub ☉}. We find that for gravitational wave sources near our best timed pulsars in the sky, the sensitivity of the pulsar timing array is increased by a factor of ∼four over the sky-averaged sensitivity. Finally we place limits on the coalescence rate of the most massive supermassive black hole binaries.
Measuring neutron-star properties via gravitational waves from neutron-star mergers.
Bauswein, A; Janka, H-T
2012-01-06
We demonstrate by a large set of merger simulations for symmetric binary neutron stars (NSs) that there is a tight correlation between the frequency peak of the postmerger gravitational-wave (GW) emission and the physical properties of the nuclear equation of state (EoS), e.g., expressed by the radius of the maximum-mass Tolman-Oppenheimer-Volkhoff configuration. Therefore, a single measurement of the peak frequency of the postmerger GW signal will constrain the NS EoS significantly. For optimistic merger-rate estimates a corresponding detection with Advanced LIGO is expected to happen within an operation time of roughly a year.
Enhanced sensitivity of the LIGO gravitational wave detector by using squeezed states of light
NASA Astrophysics Data System (ADS)
Aasi, J.; Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Affeldt, C.; Aguiar, O. D.; Ajith, P.; Allen, B.; Amador Ceron, E.; Amariutei, D.; Anderson, S. B.; Anderson, W. G.; Arai, K.; Araya, M. C.; Arceneaux, C.; Ast, S.; Aston, S. M.; Atkinson, D.; Aufmuth, P.; Aulbert, C.; Austin, L.; Aylott, B. E.; Babak, S.; Baker, P. T.; Ballmer, S.; Bao, Y.; Barayoga, J. C.; Barker, D.; Barr, B.; Barsotti, L.; Barton, M. A.; Bartos, I.; Bassiri, R.; Batch, J.; Bauchrowitz, J.; Behnke, B.; Bell, A. S.; Bell, C.; Bergmann, G.; Berliner, J. M.; Bertolini, A.; Betzwieser, J.; Beveridge, N.; Beyersdorf, P. T.; Bhadbhade, T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; Black, E.; Blackburn, J. K.; Blackburn, L.; Blair, D.; Bland, B.; Bock, O.; Bodiya, T. P.; Bogan, C.; Bond, C.; Bork, R.; Born, M.; Bose, S.; Bowers, J.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Breyer, J.; Bridges, D. O.; Brinkmann, M.; Britzger, M.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Buckland, K.; Brückner, F.; Buchler, B. C.; Buonanno, A.; Burguet-Castell, J.; Byer, R. L.; Cadonati, L.; Camp, J. B.; Campsie, P.; Cannon, K.; Cao, J.; Capano, C. D.; Carbone, L.; Caride, S.; Castiglia, A. D.; Caudill, S.; Cavaglià, M.; Cepeda, C.; Chalermsongsak, T.; Chao, S.; Charlton, P.; Chen, X.; Chen, Y.; Cho, H.-S.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, S. S. Y.; Chung, C. T. Y.; Ciani, G.; Clara, F.; Clark, D. E.; Clark, J. A.; Constancio Junior, M.; Cook, D.; Corbitt, T. R.; Cordier, M.; Cornish, N.; Corsi, A.; Costa, C. A.; Coughlin, M. W.; Countryman, S.; Couvares, P.; Coward, D. M.; Cowart, M.; Coyne, D. C.; Craig, K.; Creighton, J. D. E.; Creighton, T. D.; Cumming, A.; Cunningham, L.; Dahl, K.; Damjanic, M.; Danilishin, S. L.; Danzmann, K.; Daudert, B.; Daveloza, H.; Davies, G. S.; Daw, E. J.; Dayanga, T.; Deleeuw, E.; Denker, T.; Dent, T.; Dergachev, V.; Derosa, R.; Desalvo, R.; Dhurandhar, S.; di Palma, I.; Díaz, M.; Dietz, A.; Donovan, F.; Dooley, K. L.; Doravari, S.; Drasco, S.; Drever, R. W. P.; Driggers, J. C.; Du, Z.; Dumas, J.-C.; Dwyer, S.; Eberle, T.; Edwards, M.; Effler, A.; Ehrens, P.; Eikenberry, S. S.; Engel, R.; Essick, R.; Etzel, T.; Evans, K.; Evans, M.; Evans, T.; Factourovich, M.; Fairhurst, S.; Fang, Q.; Farr, B. F.; Farr, W.; Favata, M.; Fazi, D.; Fehrmann, H.; Feldbaum, D.; Finn, L. S.; Fisher, R. P.; Foley, S.; Forsi, E.; Fotopoulos, N.; Frede, M.; Frei, M. A.; 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.; Garcia, J.; Gehrels, N.; Gelencser, G.; Gergely, L. Á.; Ghosh, S.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Gil-Casanova, S.; Gill, C.; Gleason, J.; Goetz, E.; González, G.; Gordon, N.; Gorodetsky, M. L.; Gossan, S.; Goßler, S.; Graef, C.; Graff, P. B.; Grant, A.; Gras, S.; Gray, C.; Greenhalgh, R. J. S.; Gretarsson, A. M.; Griffo, C.; Grote, H.; Grover, K.; Grunewald, S.; Guido, C.; Gustafson, E. K.; Gustafson, R.; Hammer, D.; Hammond, G.; Hanks, J.; Hanna, C.; Hanson, J.; Haris, K.; Harms, J.; Harry, G. M.; Harry, I. W.; Harstad, E. D.; Hartman, M. T.; Haughian, K.; Hayama, K.; Heefner, J.; Heintze, M. C.; Hendry, M. A.; Heng, I. S.; Heptonstall, A. W.; Heurs, M.; Hewitson, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Holt, K.; Holtrop, M.; Hong, T.; Hooper, S.; Hough, J.; Howell, E. J.; Huang, V.; Huerta, E. A.; Hughey, B.; 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.; Jang, Y. J.; Jesse, E.; Johnson, W. W.; Jones, D.; Jones, D. I.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kasturi, R.; Katsavounidis, E.; Katzman, W.; Kaufer, H.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Keitel, D.; Kelley, D. B.; Kells, W.; Keppel, D. G.; Khalaidovski, A.; Khalili, F. Y.; Khazanov, E. A.; Kim, B. K.; Kim, C.; Kim, K.; Kim, N.; Kim, Y.-M.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Klimenko, S.; Kline, J.; Kokeyama, K.; Kondrashov, V.; Koranda, S.; Korth, W. Z.; Kozak, D.; Kozameh, C.; Kremin, A.; Kringel, V.; Krishnan, B.; Kucharczyk, C.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuper, B. J.; Kurdyumov, R.; Kwee, P.; Lam, P. K.; Landry, M.; Lantz, B.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Le Roux, A.; Leaci, P.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J.; Leong, J. R.; Levine, B.; Lhuillier, V.; Lin, A. C.; Litvine, V.; Liu, Y.; Liu, Z.; Lockerbie, N. A.; Lodhia, D.; Loew, K.; Logue, J.; Lombardi, A. L.; Lormand, M.; Lough, J.; Lubinski, M.; Lück, H.; Lundgren, A. P.; MacArthur, J.; MacDonald, E.; Machenschalk, B.; Macinnis, M.; MacLeod, D. M.; Magaña-Sandoval, F.; Mageswaran, M.; Mailand, K.; Manca, G.; Mandel, I.; Mandic, V.; Márka, S.; Márka, Z.; Markosyan, A. S.; Maros, E.; Martin, I. W.; Martin, R. M.; Martinov, D.; Marx, J. N.; Mason, K.; Matichard, F.; Matone, L.; Matzner, R. A.; Mavalvala, N.; May, G.; Mazzolo, G.; McAuley, K.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McIntyre, G.; McIver, J.; Meadors, G. D.; Mehmet, M.; Meier, T.; Melatos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messenger, C.; Meyer, M. S.; Miao, H.; Miller, J.; Mingarelli, C. M. F.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moe, B.; Mokler, F.; Mohapatra, S. R. P.; Moraru, D.; Moreno, G.; Mori, T.; Morriss, S. R.; Mossavi, K.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Mukherjee, S.; Mullavey, A.; Munch, J.; Murphy, D.; Murray, P. G.; Mytidis, A.; Nanda Kumar, D.; Nash, T.; Nayak, R.; Necula, V.; Newton, G.; Nguyen, T.; Nishida, E.; Nishizawa, A.; Nitz, A.; Nolting, D.; Normandin, M. E.; Nuttall, L. K.; O'Dell, J.; O'Reilly, B.; O'Shaughnessy, R.; Ochsner, E.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oppermann, P.; Osthelder, C.; Ott, C. D.; Ottaway, D. J.; Ottens, R. S.; Ou, J.; Overmier, H.; Owen, B. J.; Padilla, C.; Pai, A.; Pan, Y.; Pankow, C.; Papa, M. A.; Paris, H.; Parkinson, W.; Pedraza, M.; Penn, S.; Peralta, C.; Perreca, A.; Phelps, M.; Pickenpack, M.; Pierro, V.; Pinto, I. M.; Pitkin, M.; Pletsch, H. J.; Pöld, J.; Postiglione, F.; Poux, C.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; Prokhorov, L. G.; Puncken, O.; Quetschke, V.; Quintero, E.; Quitzow-James, R.; Raab, F. J.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Ramet, C.; Raymond, V.; Reed, C. M.; Reed, T.; Reid, S.; Reitze, D. H.; Riesen, R.; Riles, K.; Roberts, M.; Robertson, N. A.; Robinson, E. L.; Roddy, S.; Rodriguez, C.; Rodriguez, L.; Rodruck, M.; Rollins, J. G.; Romie, J. H.; Röver, C.; Rowan, S.; Rüdiger, A.; Ryan, K.; Salemi, F.; Sammut, L.; Sandberg, V.; Sanders, J.; Sankar, S.; Sannibale, V.; Santamaría, L.; Santiago-Prieto, I.; Santostasi, G.; Sathyaprakash, B. S.; Saulson, P. R.; Savage, R. L.; Schilling, R.; Schnabel, R.; Schofield, R. M. S.; Schuette, D.; Schulz, B.; Schutz, B. F.; Schwinberg, P.; Scott, J.; Scott, S. M.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Sergeev, A.; Shaddock, D. A.; Shahriar, M. S.; Shaltev, M.; Shao, Z.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siemens, X.; Sigg, D.; Simakov, 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.; Son, E. J.; Sorazu, B.; Souradeep, T.; Stefszky, M.; Steinert, E.; Steinlechner, J.; Steinlechner, S.; Steplewski, S.; Stevens, D.; Stochino, A.; Stone, R.; Strain, K. A.; Strigin, S. E.; Stroeer, A. S.; Stuver, A. L.; Summerscales, T. Z.; Susmithan, S.; Sutton, P. J.; Szeifert, G.; Talukder, D.; Tanner, D. B.; Tarabrin, S. P.; Taylor, R.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thorne, K. S.; Thrane, E.; Tiwari, V.; Tokmakov, K. V.; Tomlinson, C.; Torres, C. V.; Torrie, C. I.; Traylor, G.; Tse, M.; Ugolini, D.; Unnikrishnan, C. S.; Vahlbruch, H.; Vallisneri, M.; van der Sluys, M. V.; van Veggel, A. A.; Vass, S.; Vaulin, R.; Vecchio, A.; Veitch, P. J.; Veitch, J.; Venkateswara, K.; Verma, S.; Vincent-Finley, R.; Vitale, S.; Vo, T.; Vorvick, C.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A.; Wade, L.; Wade, M.; Waldman, S. J.; Wallace, L.; Wan, Y.; Wang, M.; Wang, J.; Wang, X.; Wanner, A.; Ward, R. L.; Was, M.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Welborn, T.; Wen, L.; Wessels, P.; West, M.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; Wiseman, A. G.; White, D. J.; Whiting, B. F.; Wiesner, K.; Wilkinson, C.; Willems, P. A.; Williams, L.; Williams, R.; Williams, T.; Willis, J. L.; Willke, B.; Wimmer, M.; Winkelmann, L.; Winkler, W.; Wipf, C.; Wittel, H.; Woan, G.; Wooley, R.; Worden, J.; Yablon, J.; Yakushin, I.; Yamamoto, H.; Yancey, C. C.; Yang, H.; Yeaton-Massey, D.; Yoshida, S.; Yum, H.; Zanolin, M.; Zhang, F.; Zhang, L.; Zhao, C.; Zhu, H.; Zhu, X. J.; Zotov, N.; Zucker, M. E.; Zweizig, J.
2013-08-01
Nearly a century after Einstein first predicted the existence of gravitational waves, a global network of Earth-based gravitational wave observatories is seeking to directly detect this faint radiation using precision laser interferometry. Photon shot noise, due to the quantum nature of light, imposes a fundamental limit on the attometre-level sensitivity of the kilometre-scale Michelson interferometers deployed for this task. Here, we inject squeezed states to improve the performance of one of the detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) beyond the quantum noise limit, most notably in the frequency region down to 150 Hz, critically important for several astrophysical sources, with no deterioration of performance observed at any frequency. With the injection of squeezed states, this LIGO detector demonstrated the best broadband sensitivity to gravitational waves ever achieved, with important implications for observing the gravitational-wave Universe with unprecedented sensitivity.
Bayesian parameter estimation of core collapse supernovae using gravitational wave simulations
NASA Astrophysics Data System (ADS)
Edwards, Matthew C.; Meyer, Renate; Christensen, Nelson
2014-11-01
Using the latest numerical simulations of rotating stellar core collapse, we present a Bayesian framework to extract the physical information encoded in noisy gravitational wave signals. We fit Bayesian principal component regression models with known and unknown signal arrival times to reconstruct gravitational wave signals, and subsequently fit known astrophysical parameters on the posterior means of the principal component coefficients using a linear model. We predict the ratio of rotational kinetic energy to gravitational energy of the inner core at bounce by sampling from the posterior predictive distribution, and find that these predictions are generally very close to the true parameter values, with 90% credible intervals ˜ 0.06 wide for the known and unknown arrival time models respectively. Two supervised machine learning methods are implemented to classify precollapse differential rotation, and we find that these methods discriminate rapidly rotating progenitors particularly well. We also introduce a constrained optimization approach to model selection to find an optimal number of principal components in the signal reconstruction step. Using this approach, we select 14 principal components as the most parsimonious model.
NASA Astrophysics Data System (ADS)
Bender, Peter L.
2012-03-01
In late 2011, suggestions were made of two new atom interferometry mission concepts for gravitational wave studies. [A presentation by B. N. Saif on these concepts is available on the NASA Physics of the Cosmos website under ``Workshop on Gravitational Wave Mission Architectural Concepts'' (Dec. 20-21, 2011)]. The concepts were for measurements between atom clouds separated by distances of L=500 m or L=500 km. At GW frequencies of 0.1 to 10 Hz, sinusoidal variations in the separations dX between two parts of the atom wavefunctions would be induced by motion of the nulls in the optical potential, using the Bloch oscillation approach. But some apparent limitations of this approach are as follows: the S/N required for achieving the strain sensitivities shown appears to be much higher than the value given in the example in the presentation; the large sinusoidal variations required in the control laser frequency make it difficult to use high finesse cavity mode-cleaners to reduce the effects of laser wavefront aberration fluctuations; very small fluctuations in the temperature or size of the atom clouds would cause serious additional noise, particularly for the L=500 m case; and for the L=500 mission concept, the 10-20 W suggested laser power does not seem to permit keeping the spontaneous emission rate low. However, the main issue is that the required atom interferometry systems appear to be far more complex than the gravitational reference sensors that they would replace.
Gravitational waves and scalar perturbations from spectator fields
NASA Astrophysics Data System (ADS)
Biagetti, Matteo; Dimastrogiovanni, Emanuela; Fasiello, Matteo; Peloso, Marco
2015-04-01
The most conventional mechanism for gravitational waves (gw) production during inflation is the amplification of vacuum metric fluctuations. In this case the gw production can be uniquely related to the inflationary expansion rate H. For example, a gw detection close to the present experimental limit (tensor-to-scalar ratio r ~ 0.1) would indicate an inflationary expansion rate close to 1014 GeV. This conclusion, however, would be invalid if the observed gw originated from a different source. We construct and study one of the possible covariant formulations of the mechanism suggested in [1], where a spectator field σ with a sound speed cs ll 1 acts as a source for gw during inflation. In our formulation σ is described by a so-called P(X) Lagrangian and a non-minimal coupling to gravity. This field interacts only gravitationally with the inflaton, which has a standard action. We compute the amount of scalar and tensor density fluctuations produced by σ and find that, in our realization, r is not enhanced with respect to the standard result but it is strongly sensitive to cs, thus breaking the direct r leftrightarrow H connection.
Gravitational, shear and matter waves in Kantowski-Sachs cosmologies
Keresztes, Zoltán; Gergely, László Á.; Forsberg, Mats; Bradley, Michael; Dunsby, Peter K.S. E-mail: forsberg.mats.a.b@gmail.com E-mail: peter.dunsby@uct.ac.za
2015-11-01
A general treatment of vorticity-free, perfect fluid perturbations of Kantowski-Sachs models with a positive cosmological constant are considered within the framework of the 1+1+2 covariant decomposition of spacetime. The dynamics is encompassed in six evolution equations for six harmonic coefficients, describing gravito-magnetic, kinematic and matter perturbations, while a set of algebraic expressions determine the rest of the variables. The six equations further decouple into a set of four equations sourced by the perfect fluid, representing forced oscillations and two uncoupled damped oscillator equations. The two gravitational degrees of freedom are represented by pairs of gravito-magnetic perturbations. In contrast with the Friedmann case one of them is coupled to the matter density perturbations, becoming decoupled only in the geometrical optics limit. In this approximation, the even and odd tensorial perturbations of the Weyl tensor evolve as gravitational waves on the anisotropic Kantowski-Sachs background, while the modes describing the shear and the matter density gradient are out of phase dephased by π /2 and share the same speed of sound.
DOUBLE COMPACT OBJECTS. III. GRAVITATIONAL-WAVE DETECTION RATES
Dominik, Michal; Belczynski, Krzysztof; Bulik, Tomasz; Berti, Emanuele; O’Shaughnessy, Richard; Mandel, Ilya; Fryer, Christopher; Holz, Daniel E.; Pannarale, Francesco
2015-06-20
The unprecedented range of second-generation gravitational-wave (GW) observatories calls for refining the predictions of potential sources and detection rates. The coalescence of double compact objects (DCOs)—i.e., neutron star–neutron star (NS–NS), black hole–neutron star (BH–NS), and black hole–black hole (BH–BH) binary systems—is the most promising source of GWs for these detectors. We compute detection rates of coalescing DCOs in second-generation GW detectors using the latest models for their cosmological evolution, and implementing inspiral-merger-ringdown gravitational waveform models in our signal-to-noise ratio calculations. We find that (1) the inclusion of the merger/ringdown portion of the signal does not significantly affect rates for NS–NS and BH–NS systems, but it boosts rates by a factor of ∼1.5 for BH–BH systems; (2) in almost all of our models BH–BH systems yield by far the largest rates, followed by NS–NS and BH–NS systems, respectively; and (3) a majority of the detectable BH–BH systems were formed in the early universe in low-metallicity environments. We make predictions for the distributions of detected binaries and discuss what the first GW detections will teach us about the astrophysics underlying binary formation and evolution.
Gravitational, shear and matter waves in Kantowski-Sachs cosmologies
NASA Astrophysics Data System (ADS)
Keresztes, Zoltán; Forsberg, Mats; Bradley, Michael; Dunsby, Peter K. S.; Gergely, László Á.
2015-11-01
A general treatment of vorticity-free, perfect fluid perturbations of Kantowski-Sachs models with a positive cosmological constant are considered within the framework of the 1+1+2 covariant decomposition of spacetime. The dynamics is encompassed in six evolution equations for six harmonic coefficients, describing gravito-magnetic, kinematic and matter perturbations, while a set of algebraic expressions determine the rest of the variables. The six equations further decouple into a set of four equations sourced by the perfect fluid, representing forced oscillations and two uncoupled damped oscillator equations. The two gravitational degrees of freedom are represented by pairs of gravito-magnetic perturbations. In contrast with the Friedmann case one of them is coupled to the matter density perturbations, becoming decoupled only in the geometrical optics limit. In this approximation, the even and odd tensorial perturbations of the Weyl tensor evolve as gravitational waves on the anisotropic Kantowski-Sachs background, while the modes describing the shear and the matter density gradient are out of phase dephased by π /2 and share the same speed of sound.
Gravitational waves and scalar perturbations from spectator fields
Biagetti, Matteo; Dimastrogiovanni, Emanuela; Peloso, Marco; Fasiello, Matteo E-mail: emanuela1573@gmail.com E-mail: peloso@physics.umn.edu
2015-04-01
The most conventional mechanism for gravitational waves (gw) production during inflation is the amplification of vacuum metric fluctuations. In this case the gw production can be uniquely related to the inflationary expansion rate H. For example, a gw detection close to the present experimental limit (tensor-to-scalar ratio r ∼ 0.1) would indicate an inflationary expansion rate close to 10{sup 14} GeV. This conclusion, however, would be invalid if the observed gw originated from a different source. We construct and study one of the possible covariant formulations of the mechanism suggested in [1], where a spectator field σ with a sound speed c{sub s} || 1 acts as a source for gw during inflation. In our formulation σ is described by a so-called P(X) Lagrangian and a non-minimal coupling to gravity. This field interacts only gravitationally with the inflaton, which has a standard action. We compute the amount of scalar and tensor density fluctuations produced by σ and find that, in our realization, r is not enhanced with respect to the standard result but it is strongly sensitive to c{sub s}, thus breaking the direct r ↔ H connection.
The path to a gravitational-wave detector in space
NASA Astrophysics Data System (ADS)
Mueller, Guido
2017-01-01
Following the selection of the Gravitational Universe for the third large mission (L3) by ESA and NASA's interest in partnering with ESA, we are now about a dozen years away from the earliest possible launch of the first space-based observatory. The idea of such an observatory was first formulated about a dozen years after Gertsenshtein and Pustovoit in the USSR and later Weber and Weiss in the US voiced their ideas of using laser interferometer for ground-based gravitational wave observatories. The design of the L3 mission will likely follow the LISA design which was developed from the late 1990's until the original LISA project was terminated in 2011. The revised LISA mission will detect many mergers between massive and super-massive black holes out to large redshifts, will detect solar mass black holes years before they produce merger signals in ground-based observatories, will measure the distribution of compact galactic binaries and test general relativity in the strong relativistic regime with large signal to noise ratio. I will review the scientific motivation for LISA, present its status, and discuss the next steps towards its realization.
Architectures for a Space-based Gravitational-Wave Observatory
NASA Astrophysics Data System (ADS)
Stebbins, Robin
2015-04-01
The European Space Agency (ESA) selected the science theme, the ``Gravitational Universe,'' for the third large mission opportunity, known as L3, under its Cosmic Vision Programme. The planned launch date is 2034. ESA is considering a 20% participation by an international partner, and NASA's Astrophysics Division has begun negotiating a NASA role. We have studied the design consequences of a NASA contribution, evaluated the science benefits and identified the technology requirements for hardware that could be delivered by NASA. The European community proposed a strawman mission concept, called eLISA, having two measurement arms, derived from the well studied LISA (Laser Interferometer Space Antenna) concept. The US community is promoting a mission concept known as SGO Mid (Space-based Gravitational-wave Observatory Mid-sized), a three arm LISA-like concept. If NASA were to partner with ESA, the eLISA concept could be transformed to SGO Mid by the addition of a third arm, thereby augmenting science, reducing risk and reducing non-recurring engineering costs. The characteristics of the mission concepts and the relative science performance of eLISA, SGO Mid and LISA are described.
Cross-correlation search for periodic gravitational waves
Dhurandhar, Sanjeev; Mukhopadhyay, Himan; Krishnan, Badri; Whelan, John T.
2008-04-15
In this paper we study the use of cross correlations between multiple gravitational wave (GW) data streams for detecting long-lived periodic signals. Cross-correlation searches between data from multiple detectors have traditionally been used to search for stochastic GW signals, but recently they have also been used in directed searches for periodic GWs. Here we further adapt the cross-correlation statistic for periodic GW searches by taking into account both the nonstationarity and the long-term-phase coherence of the signal. We study the statistical properties and sensitivity of this search and its relation to existing periodic wave searches, and describe the precise way in which the cross-correlation statistic interpolates between semicoherent and fully coherent methods. Depending on the maximum duration over which we wish to preserve phase coherence, the cross-correlation statistic can be tuned to go from a standard cross-correlation statistic using data from distinct detectors, to the semicoherent time-frequency methods with increasing coherent time baselines, and all the way to a full coherent search. This leads to a unified framework for studying periodic wave searches and can be used to make informed trade-offs between computational cost, sensitivity, and robustness against signal uncertainties.
Search for Gravitational Waves from Intermediate Mass Binary Black Holes
NASA Technical Reports Server (NTRS)
Blackburn, L.; Camp, J. B.; Cannizzo, J.; Stroeer, A. S.
2012-01-01
We present the results of a weakly modeled burst search for gravitational waves from mergers of non-spinning intermediate mass black holes (IMBH) in the total mass range 100-450 solar Mass and with the component mass ratios between 1:1 and 4:1. The search was conducted on data collected by the LIGO and Virgo detectors between November of 2005 and October of 2007. No plausible signals were observed by the search which constrains the astrophysical rates of the IMBH mergers as a function of the component masses. In the most efficiently detected bin centered on 88 + 88 solar Mass , for non-spinning sources, the rate density upper limit is 0.13 per Mpc(exp 3) per Myr at the 90% confidence level.
Observational Selection Effects with Ground-based Gravitational Wave Detectors
NASA Astrophysics Data System (ADS)
Chen, Hsin-Yu; Essick, Reed; Vitale, Salvatore; Holz, Daniel; Katsavounidis, Erik
2017-01-01
Ground-based interferometers are not perfectly all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean and, as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources' right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO's observations and electromagnetic follow-up. These effects can inform electromagnetic follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.
Distributional Tests for Gravitational Waves from Core-Collapse Supernovae
NASA Astrophysics Data System (ADS)
Szczepanczyk, Marek; LIGO Collaboration
2017-01-01
Core-Collapse Supernovae (CCSN) are spectacular and violent deaths of massive stars. CCSN are some of the most interesting candidates for producing gravitational-waves (GW) transients. Current published results focus on methodologies to detect single GW unmodelled transients. The advantages of these tests are that they do not require a background for which we have an analytical model. Examples of non-parametric tests that will be compared are Kolmogorov-Smirnov, Mann-Whitney, chi squared, and asymmetric chi squared. I will present methodological results using publicly released LIGO-S6 data recolored to the design sensitivity of Advanced LIGO and that will be time lagged between interferometers sites so that the resulting coincident events are not GW.
Gravitational wave background and Higgs false vacuum inflation
NASA Astrophysics Data System (ADS)
Masina, Isabella
2014-06-01
For a narrow band of values of the top quark and Higgs boson masses, the standard model Higgs potential develops a shallow local minimum at energies of about 1016 GeV, where primordial inflation could have started in a cold metastable state. For each point of that band, the highness of the Higgs potential at the false minimum is calculable, and there is an associated prediction for the inflationary gravitational wave background, namely, for the tensor to scalar ratio r. We show that the recent measurement of r by the BICEP2 collaboration, r =0.16-0.05+0.06 at 1σ, combined with the most up-to-date measurements of the top quark and Higgs boson masses, reveals that the hypothesis that a standard model shallow false minimum was the source of inflation in the early Universe is viable.
New Concepts for Space-Based Gravitational Wave Missions
NASA Technical Reports Server (NTRS)
Stebbins, Robin T.; Baker, J. G.; Cooley, D. S.; Gallagher, R. J.; Hughes, S. P.; Livas, J. C.; Simpson, J. E.; Thorpe, J. I.; Welter, G. L.
2011-01-01
The most astrophysically interesting sources in the gravitational wave spectrum lie in the low-frequency band (0.0001 - 1 Hz), which is only accessible from space. For two decades, the LISA concept has been the leading contender for a detector in this band. Despite a strong recommendation from Astro2010, there is strong motivation to find a less expensive concept, even at the loss of some science. We are searching for a lower cost mission concept by examining alternate orbits, less-capable measurement concepts, radically different implementations of the measurement concept and other cost-saving ideas. We report the results of our searches to date, and summarize the analyses behind them.
Residual amplitude modulation in interferometric gravitational wave detectors.
Kokeyama, Keiko; Izumi, Kiwamu; Korth, William Z; Smith-Lefebvre, Nicolas; Arai, Koji; Adhikari, Rana X
2014-01-01
The effects of residual amplitude modulation (RAM) in laser interferometers using heterodyne sensing can be substantial and difficult to mitigate. In this work, we analyze the effects of RAM on a complex laser interferometer used for gravitational wave detection. The RAM introduces unwanted offsets in the cavity length signals and thereby shifts the operating point of the optical cavities from the nominal point via feedback control. This shift causes variations in the sensing matrix, and leads to degradation in the performance of the precision noise subtraction scheme of the multiple-degree-of-freedom control system. In addition, such detuned optical cavities produce an optomechanical spring, which also perturbs the sensing matrix. We use our simulations to derive requirements on RAM for the Advanced LIGO (aLIGO) detectors, and show that the RAM expected in aLIGO will not limit its sensitivity.
Anisotropies in the gravitational wave background from preheating.
Bethke, Laura; Figueroa, Daniel G; Rajantie, Arttu
2013-07-05
We investigate the anisotropies in the gravitational wave (GW) background produced at preheating after inflation. Using lattice field theory simulations of a massless preheating model, we show that the GW amplitude depends sensitively on the value of the decay product field χ coupled to the inflaton φ, with the only requisite that χ is light during inflation. We find a strong anisotropy in the amplitude of the GW background on large angular scales, the details of which strongly depend on the reheating dynamics. We expect similar conclusions for a wide class of inflationary models with light scalar fields. If future direct detection GW experiments are capable of detecting the GW produced by preheating, they should also be able to detect this effect. This could eventually provide a powerful way to distinguish between different inflationary and preheating scenarios.
Identifying Electromagnetic Counterparts to Gravitational Wave Triggers With DECam
NASA Astrophysics Data System (ADS)
Cowperthwaite, Philip
2016-03-01
Identifying the electromagnetic counterpart to a gravitational wave (GW) event is one of the great observational challenges in modern astronomy. We report on our work to overcome this challenge by investigating the theoretical and practical issues associated with optical follow-up of a GW event. This includes a systematic study of the potential contaminant population and their impact on counterpart detectability in simulated observations. Additionally, we utilize data taken with the Dark Energy Camera (DECam) on the Blanco 4-m telescope at CTIO. These data serve as a mock follow-up to a GW event and assist in the characterization of contamination not captured in simulations. P.S.C. is grateful for support provided by the NSF through the Graduate Research Fellowship Program, Grant DGE1144152.
FY15 Gravitational-Wave Mission Activities Project
NASA Technical Reports Server (NTRS)
Stebbins, Robin T.
2014-01-01
The Gravitational-Wave (GW) team at Goddard provides leadership to both the US and international research communities through science and conceptual design competencies. To sustain the US effort to either participate in the GW mission that ESA selected for the L3 opportunity or to initiate a NASA-led mission, the Goddard team will engage in the advancement of the science and the conceptual design of a future GW mission. We propose two tasks: (1) deliver new theoretical tools to help the external research community understand how GW observations can contribute to their science and (2) explore new implementations for laser metrology systems based on techniques from time-domain reflectometry and laser communications.
Gravitational wave asteroseismology with fast rotating neutron stars
Gaertig, Erich; Kokkotas, Kostas D.
2011-03-15
We investigate damping and growth times of the quadrupolar f mode for rapidly rotating stars and a variety of different polytropic equations of state in the Cowling approximation. This is the first study of the damping/growth time of these types of oscillations for fast-rotating neutron stars in a relativistic treatment where the spacetime degrees of freedom of the perturbations are neglected. We use these frequencies and damping/growth times to create robust empirical formulae which can be used for gravitational-wave asteroseismology. The estimation of the damping/growth time is based on the quadrupole formula and our results agree very well with Newtonian ones in the appropriate limit.
NASA Sees Orbiting Stars Flooding Space with Gravitational Waves
NASA Astrophysics Data System (ADS)
2005-05-01
A scientist using NASA's Chandra X-ray Observatory has found evidence that two white dwarf stars are orbiting each other in a death grip, destined to merge. The data indicate that gravitational waves are carrying energy away from the star system at a prodigious rate - making it a prime candidate for future missions designed to directly detect these subtle ripples in space-time. Einstein's General Theory of Relativity predicts that a binary star system should emit gravitational waves, which rush away at the speed of light and cause the stars to move closer together. The orbital period of this system, known as RX J0806.3+1527, or J0806, is decreasing by 1.2 milliseconds every year, a rate consistent with theory. Animation of White Dwarfs Animation of White Dwarfs The white dwarf pair in J0806 might have the smallest orbit of any known binary system with the stars only about 50,000 miles apart, a fifth of the distance from the Earth to the Moon. As the stars swirl closer together, traveling in excess of a million miles per hour, the production of gravitational waves increases. "If confirmed, J0806 could be one of the brightest sources of gravitational waves in our Galaxy," said Tod Strohmayer of NASA's Goddard Space Flight Center of Greenbelt, Md., who presents his results today at the American Astronomical Society meeting in Minneapolis, Minn. "It could be among the first to be detected directly with an upcoming space mission called LISA, the Laser Interferometer Space Antenna." White dwarfs are remnants of stars like our Sun that have used up all their fuel. Along with neutron stars and black holes, white dwarfs are called compact objects because they pack a lot of mass into a small volume. The white dwarfs in the J0806 system each have an estimated mass half that of the Sun, yet are only about the size of Earth. Chandra Light Curve of RX J0806.3+1527 Chandra Light Curve of RX J0806.3+1527 Optical and X-ray observations of J0806 show periodic variations with a
Mild bounds on bigravity from primordial gravitational waves
Fasiello, Matteo; Ribeiro, Raquel H. E-mail: R.Ribeiro@qmul.ac.uk
2015-07-01
If the amplitude of primordial gravitational waves is measured in the near-future, what could it tell us about bigravity? To address this question, we study massive bigravity theories by focusing on a region in parameter space which is safe from known instabilities. Similarly to investigations on late time constraints, we implicitly assume there is a successful implementation of the Vainshtein mechanism which guarantees that standard cosmological evolution is largely unaffected. We find that viable bigravity models are subject to far less stringent constraints than massive gravity, where there is only one set of (massive) tensor modes. In principle sensitive to the effective graviton mass at the time of recombination, we find that in our setup the primordial tensor spectrum is more responsive to the dynamics of the massless tensor sector rather than its massive counterpart. We further show there are intriguing windows in the parameter space of the theory which could potentially induce distinct signatures in the B-modes spectrum.
Gravitational wave sirens as a triple probe of dark energy
Linder, Eric V
2008-03-15
Gravitational wave standard sirens have been considered as precision distance indicators of high redshift; however, at high redshift standard sirens or standard candles such as supernovae suffer from lensing noise. We investigate lensing noise as a signal instead and show how measurements of the maximum demagnification (minimum convergence) probe cosmology in a manner highly complementary to the distance itself. Revisiting the original form for minimum convergence we quantify the bias arising from the commonly used approximation. Furthermore, after presenting a new lensing probability function we discuss how the width of the lensed standard siren amplitude distribution also probes growth of structure. Thus standard sirens and candles can serve as triple probes of dark energy, measuring both the cosmic expansion history and growth history.
Gravitational wave sirens as a triple probe of dark energy
NASA Astrophysics Data System (ADS)
Linder, Eric V.
2008-03-01
Gravitational wave standard sirens have been considered as precision distance indicators of high redshift; however, at high redshift standard sirens or standard candles such as supernovae suffer from lensing noise. We investigate lensing noise as a signal instead and show how measurements of the maximum demagnification (minimum convergence) probe cosmology in a manner highly complementary to the distance itself. Revisiting the original form for minimum convergence we quantify the bias arising from the commonly used approximation. Furthermore, after presenting a new lensing probability function we discuss how the width of the lensed standard siren amplitude distribution also probes growth of structure. Thus standard sirens and candles can serve as triple probes of dark energy, measuring both the cosmic expansion history and growth history.
Pulsar timing sensitivity to very-low-frequency gravitational waves
Jenet, Fredrick A.; Armstrong, J. W.; Tinto, Massimo
2011-04-15
We compute the sensitivity, constrained by instrumental, propagation, and other fundamental noises, of pulsar timing to very-low-frequency gravitational waves (GWs). Reaching predicted GW signal strengths will require suppression of time-of-arrival fluctuations caused by interstellar plasma turbulence and a reduction of white rms timing noise to < or approx. 100 ns. Assuming negligible intrinsic pulsar rotational noise, perfect time transfer from time standard to observatory, and stable pulse profiles, the resulting single-pulsar signal-to-noise ratio=1 sensitivity is limited by terrestrial time standards at h{sub rms}{approx}2x10{sup -16} [f/ (1 cycle/year)]-1/2 for f<3x10{sup -8} Hz, where f is the Fourier frequency and a bandwidth of 1 cycle/(10 years) is assumed. Since this sensitivity is comparable to predicted GW signal levels, a reliable detection will require substantial signal-to-noise ratio improvement via pulsar timing array.