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.
The Influence of High-Frequency Gravitational Waves Upon Muscles
Moy, Lawrence S.; Baker, Robert M. L. Jr
2007-01-30
The objective of this paper is to present a theory for the possible influence of high-frequency gravitational waves or HFGWs and pulsed micro-current electromagnetic waves or EMs on biological matter specifically on muscle cells and myofibroblasts. The theory involves consideration of the natural frequency of contractions and relaxations of muscles, especially underlying facial skin, and the possible influence of HFGWs on that process. GWs pass without attenuation through all material thus conventional wisdom would dictate that GWs would have no influence on biological matter. On the other hand, GWs can temporarily modify a gravitational field in some locality if they are of high frequency and such a modification might have an influence in changing the skin muscles' natural frequency. Prior to the actual laboratory generation of HFGWs their influence can be emulated by micro-current EM pulses to the skin and some evidence presented here on that effect may predict the influence of HFGWs. We believe that the HFGW pulsations lead to increased muscle activity and may serve to reverse the aging process. A novel theoretical framework concerning these relaxation phenomena is one result of the paper. Another result is the analysis of the possible delivery system of the FBAR-generated HFGWs, the actual power of the generated HFGWs, and the system's application to nanostructural modification of the skin or muscle cells. It is concluded that a series of non-evasive experiments, which are identified, will have the potential to test theory by detecting and analyzing the possible HFGWs change in polarization, refraction, etc. after their interaction with the muscle cells.
Detecting high-frequency gravitational waves with optically levitated sensors.
Arvanitaki, Asimina; Geraci, Andrew A
2013-02-15
We propose a tunable resonant sensor to detect gravitational waves in the frequency range of 50-300 kHz using optically trapped and cooled dielectric microspheres or microdisks. The technique we describe can exceed the sensitivity of laser-based gravitational wave observatories in this frequency range, using an instrument of only a few percent of their size. Such a device extends the search volume for gravitational wave sources above 100 kHz by 1 to 3 orders of magnitude, and could detect monochromatic gravitational radiation from the annihilation of QCD axions in the cloud they form around stellar mass black holes within our galaxy due to the superradiance effect.
High-Frequency Gravitational Wave Induced Nuclear Fusion
NASA Astrophysics Data System (ADS)
Fontana, Giorgio; Baker, Robert M. L.
2007-01-01
Nuclear fusion is a process in which nuclei, having a total initial mass, combine to produce a single nucleus, having a final mass less than the total initial mass. Below a given atomic number the process is exothermic; that is, since the final mass is less than the combined initial mass and the mass deficit is converted into energy by the nuclear fusion. On Earth nuclear fusion does not happen spontaneously because electrostatic barriers prevent the phenomenon. To induce controlled, industrial scale, nuclear fusion, only a few methods have been discovered that look promising, but net positive energy production is not yet possible because of low overall efficiency of the systems. In this paper we propose that an intense burst of High Frequency Gravitational Waves (HFGWs) could be focused or beamed to a target mass composed of appropriate fuel or target material to efficiently rearrange the atomic or nuclear structure of the target material with consequent nuclear fusion. Provided that efficient generation of HFGW can be technically achieved, the proposed fusion reactor could become a viable solution for the energy needs of mankind and alternatively a process for beaming energy to produce a source of fusion energy remotely — even inside solid materials.
High-Frequency Gravitational Wave Induced Nuclear Fusion
Fontana, Giorgio; Baker, Robert M. L. Jr.
2007-01-30
Nuclear fusion is a process in which nuclei, having a total initial mass, combine to produce a single nucleus, having a final mass less than the total initial mass. Below a given atomic number the process is exothermic; that is, since the final mass is less than the combined initial mass and the mass deficit is converted into energy by the nuclear fusion. On Earth nuclear fusion does not happen spontaneously because electrostatic barriers prevent the phenomenon. To induce controlled, industrial scale, nuclear fusion, only a few methods have been discovered that look promising, but net positive energy production is not yet possible because of low overall efficiency of the systems. In this paper we propose that an intense burst of High Frequency Gravitational Waves (HFGWs) could be focused or beamed to a target mass composed of appropriate fuel or target material to efficiently rearrange the atomic or nuclear structure of the target material with consequent nuclear fusion. Provided that efficient generation of HFGW can be technically achieved, the proposed fusion reactor could become a viable solution for the energy needs of mankind and alternatively a process for beaming energy to produce a source of fusion energy remotely - even inside solid materials.
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)
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)
Proposed Ultra-High Sensitivity High-Frequency Gravitational Wave Detector
NASA Astrophysics Data System (ADS)
Baker, Robert M. L.; Stephenson, Gary V.; Li, Fangyu
2008-01-01
The paper discusses the proposed improvement of a High-Frequency Relic Gravitational Wave (HFRGW) detector designed by Li, Baker, Fang, Stephenson and Chen in order to greatly improve its sensitivity. The improved detector is inspired by the Laser Interferometer Gravitational Observatory or LIGO, but is sensitive to the high-frequency end of the gravitational-wave spectrum. As described in prior papers it utilizes the Gertsenshtein effect, which introduces the conversion of gravitational waves to electromagnetic (EM) waves in the presence of a static magnetic field. Such a conversion, if it leads to photons moving in a direction perpendicular to the plane of the EM waves and the magnetic field, will allow for ultra-high sensitivity HFRGW detection. The use of sensitive microwave, single photon detectors such as a circuit QED and/or the Rydberg Atom Cavity Detector, or off-the-shelf detectors, could lead to such detection. When the EM-detection photons are focused at the microwave detectors by fractal-membrane reflectors sensitivity is also improved. Noise sources external to the HFRGW detector will be eliminated by placing a tight mosaic of superconducting tiles (e.g., YBCO) and/or fractal membranes on the interior surface of the detector's cryogenic containment vessel in order to provide a perfect Faraday cage. Internal thermal noise will be eliminated by means of a microwave absorbing (or reflecting) interior enclosure shaped to conform to a high-intensity continuous microwave Gaussian beam (GB), will reduce any background photon flux (BPF) noise radiated normal to the GB's axis. Such BPF will be further attenuated by a series of microwave absorbing baffles forming tunnels to the sensitive microwave detectors on each side of the GB and at right angles to the static magnetic field. A HFGW detector of bandwidth of 1 KHz to 10 KHz or less in the GHz band has been selected. It is concluded that the utilization of the new ultra-high-sensitivity microwave detectors
Resonance of Gaussian Electromagnetic Field to the High Frequency Gravitational Waves
NASA Astrophysics Data System (ADS)
Li, Jin; Zhang, Lu; Lin, Kai; Wen, Hao
2016-08-01
We consider a Gaussian Beam (GB) resonant system for high frequency gravitational waves (HFGWs) detection. At present, we find the optimal signal strength in theory through setting the magnetic component of GB in a standard gaussian form. Under the synchro-resonance condition, we study the signal strength (i.e., transverse perturbative photon fluxes) from the relic HFGWs (predicted by ordinary inflationary model) and the braneworld HFGWs (from braneworld scenarios). Both of them would generate potentially detectable transverse perturbative photon fluxes (PPFs). Furthermore we find optimal system parameters and the relationship between frequency and effective width of energy fluxes accumulation.
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.
Relic High Frequency Gravitational waves from the Big Bang and How to Detect Them
Beckwith, Andrew
2009-03-16
This paper shows how entropy generation from numerical density calculations of relic gravitons can be measured via the Li-Baker high-frequency gravity wave (HFGW) detector, and suggests the implications this has for the physics of early-universe phase transitions. This paper indicates the role of Ng's revised statistics in gravitational wave physics detection and the application of Baumann et al.(2007) formalism of reduction of rank-two tensorial contributions to density wave physics, using the HFGW approximation directly at the beginning as well as Li's treatment of energy density explicitly. This formalism is a way to refine and add more capacity to the Li-Baker HFGW detector in reconstructing early-universe conditions at the onset of the big bang.
Kocsis, Bence
2013-02-15
It is commonly assumed that ground-based gravitational wave (GW) instruments will not be sensitive to supermassive black holes (SMBHs) because the characteristic GW frequencies are far below the {approx}10-1000 Hz sensitivity bands of terrestrial detectors. Here, however, we explore the possibility of SMBH GWs to leak to higher frequencies. In particular, if the high-frequency spectral tail asymptotes to h-tilde (f){proportional_to}f{sup -{alpha}}, where {alpha} {<=} 2, then the spectral amplitude is a constant or increasing function of the mass M at a fixed frequency f >> c {sup 3}/GM. This will happen if the time-domain waveform or its derivative exhibits a discontinuity. Ground-based instruments could search for these universal spectral tails to detect or rule out such features irrespective of their origin. We identify the following processes which may generate high-frequency signals: (1) gravitational bremsstrahlung of ultrarelativistic objects in the vicinity of an SMBH, (2) ringdown modes excited by an external process that has a high-frequency component or terminates abruptly, and (3) gravitational lensing echoes and diffraction. We estimate the order of magnitude of the detection signal-to-noise ratio for each mechanism (1, 2, and 3) as a function of the waveform parameters. In particular for (3), SMBHs produce GW echoes of inspiraling stellar mass binaries in galactic nuclei with a delay of a few minutes to hours. The lensed primary signal and GW echo are both amplified if the binary is within a {approx}10 deg (r/100M){sup -1/2} cone behind the SMBH relative to the line of sight at a distance r from the SMBH. For the rest of the binaries near SMBHs, the amplitude of the GW echo is {approx}0.1(r/100M){sup -1} of the primary signal on average.
NASA Astrophysics Data System (ADS)
Li, Fangyu; Wen, Hao; Fang, Zhenyun; Wei, Lianfu; Wang, Yiwen; Zhang, Miao
2016-10-01
Interaction of very low-frequency primordial (relic) gravitational waves (GWs) to cosmic microwave background (CMB) can generate B-mode polarization. Here, for the first time we point out that the electromagnetic (EM) response to high-frequency GWs (HFGWs) would produce quasi-B-mode distribution of the perturbative photon fluxes. We study the duality and high complementarity between such two B-modes, and it is shown that such two effects are from the same physical origin: the tensor perturbation of the GWs and not the density perturbation. Based on this quasi-B-mode in HFGWs and related numerical calculation, it is shown that the distinguishing and observing of HFGWs from the braneworld would be quite possible due to their large amplitude, higher frequency and very different physical behaviors between the perturbative photon fluxes and background photons, and the measurement of relic HFGWs may also be possible though face to enormous challenge.
Squeezed light for the interferometric detection of high-frequency gravitational waves
NASA Astrophysics Data System (ADS)
Schnabel, R.; Harms, J.; Strain, K. A.; Danzmann, K.
2004-03-01
The quantum noise of the light field is a fundamental noise source in interferometric gravitational-wave detectors. Injected squeezed light is capable of reducing the quantum noise contribution to the detector noise floor to values that surpass the so-called standard quantum limit (SQL). In particular, squeezed light is useful for the detection of gravitational waves at high frequencies where interferometers are typically shot-noise limited, although the SQL might not be beaten in this case. We theoretically analyse the quantum noise of the signal-recycled laser interferometric gravitational-wave detector GEO 600 with additional input and output optics, namely frequency-dependent squeezing of the vacuum state of light entering the dark port and frequency-dependent homodyne detection. We focus on the frequency range between 1 kHz and 10 kHz, where, although signal recycled, the detector is still shot-noise limited. It is found that the GEO 600 detector with present design parameters will benefit from frequency-dependent squeezed light. Assuming a squeezing strength of -6 dB in quantum noise variance, the interferometer will become thermal noise limited up to 4 kHz without further reduction of bandwidth. At higher frequencies the linear noise spectral density of GEO 600 will still be dominated by shot noise and improved by a factor of 106dB/20dB ap 2 according to the squeezing strength assumed. The interferometer might reach a strain sensitivity of 6 × 10-23 above 1 kHz (tunable) with a bandwidth of around 350 Hz. We propose a scheme to implement the desired frequency-dependent squeezing by introducing an additional optical component into GEO 600's signal-recycling cavity.
NASA Astrophysics Data System (ADS)
Baker, Robert M. L.; Woods, R. Clive; Li, Fangyu
2006-01-01
Here we show the generation of high-frequency-gravitational-waves (HFGWs) utilizing piezoelectric elements such as the ubiquitous Film-Bulk-Acoustic-Resonators (FBARs), found in cell phones, as energized by inexpensive magnetrons, found in microwave ovens, generating GWs having a frequency of about 4.9GHz and their detection by means of new synchro-resonance techniques developed in China. In the 1960s Weber suggested piezoelectric crystals for gravitational-wave (GW) generation. Since then researchers have proposed specific designs. The major obstacle has been the cost of procuring, installing, and energizing a sufficient number of such resonators to generate sufficiently powerful GWs to allow for detection. Recent mass-production techniques, spurred on by the production of cell phones, have driven the cost of resonators down. The new Chinese detector for detecting the 4.9×109Hz HFGW is a coupling-system of fractal membranes-beam-splitters and a narrow, 6.1 cm-radius, pulsed-Gaussian-laser or continuous-Gaussian detection beam passing through a static 15T-magnetic field. The detector is sensitive to GW amplitudes of ~10-30 to be generated with signal-to-noise ratios greater than one. It is concluded that a cost-effective HFGW generation and detection apparatus can now be fabricated and operated in the laboratory. If the two groups or clusters of magnetrons and FBARs were space borne and at lunar distance (e.g., at the Moon and at the lunar L3 libration point) and the quadrupole formalism approximately holds for GW radiators (the FBAR clusters) many GW wavelengths apart, then the HFGW power would be about 420 W and the flux about 2×105 Wm-2 (or more than one hundred times greater than the solar radiation flux at the Earth) focused at the focal spot, or remote-HFGW-emitter, anywhere in the Earth's environs - on or below the Earth's surface.
Applications of High-Frequency Gravitational Waves to the Global War on Terror
NASA Astrophysics Data System (ADS)
Baker, Robert M. L.
2010-01-01
Applications of high-frequency gravitational waves or HFGWs to the global war on terror are now realistic because technology developed by GravWave® LLC and other institutions overseas can lead to devices, some already constructed, that can generate and detect HFGWs. In fact, three HFGW detectors have been built outside the United States and an ultra high-sensitive Li-Baker HFGW Detector has been proposed. HFGW generators have been proposed theoretically by the Russians, Germans, Italians and Chinese. Because of their unique characteristics, such as their ability to pass through all material without attenuation, HFGWs could be utilized for uninterruptible, very low-probability-of-intercept (LPI), high-bandwidth communications among and between anti-terrorist assets. One such communications system, which can be constructed from off-the-shelf elements, is discussed. The HFGW generation device or transmitter alternative selected is based upon bands of piezoelectric crystal, film-bulk acoustic resonators or FBARs energized by conventional Magnetrons. The system is theoretically capable of transmitting and detecting, through use of the Li-Baker HFGW detector, a signal generated on the opposite side of the Earth. Although HFGWs do not interact with and are not absorbed by ordinary matter, their presence can be detected by their distortion of spacetime as measured by the Laser Interferometer Gravitational Observatory (LIGO), Virgo, GEO600, et al., by detection photons generated from electromagnetic beams having the same frequency, direction and phase as the HFGWs in a superimposed magnetic field (Li-Baker HFGW Detector), by the change in polarization HFGWs produce in a microwave guide (Birmingham University Detector) and by other such instruments. Potential theoretical applications, which may or may not be practical yet theoretically possible, are propulsion, including "moving" space objects such as missiles, anti-missiles and warheads in flight; surveillance through
Relic gravitational waves with a running spectral index and its constraints at high frequencies
Tong, M. L.; Zhang, Y.
2009-10-15
We study the impact of a running index {alpha}{sub t} on the spectrum of relic gravitational waves (RGWs) over the whole range of frequency (10{sup -18}{approx}10{sup 10}) Hz and reveal its implications in RGWs detections and in cosmology. Analytical calculations show that, although the spectrum of RGWs on low frequencies is less affected by {alpha}{sub t}{ne}0, on high frequencies, the spectrum is modified substantially. Investigations are made toward potential detections of the {alpha}{sub t}-modified RGWs for several kinds of current and planned detectors. The Advanced LIGO will likely be able to detect RGWs with {alpha}{sub t}{>=}0 for inflationary models with the inflation index {beta}=-1.956 and the tensor-scalar ratio r=0.55. The future LISA can detect RGWs for a much broader range of ({alpha}{sub t},{beta},r), and will have a better chance to break a degeneracy between them. Constraints on {alpha}{sub t} are estimated from several detections and cosmological observations. Among them, the most stringent one is from the bound of the big bang nucleosynthesis, and requires {alpha}{sub t}<0.008 rather conservatively for any reasonable ({beta},r), preferring a nearly power-law spectrum of RGWs. In light of this result, one would expect the scalar running index {alpha}{sub s} to be of the same magnitude as {alpha}{sub t}, if both RGWs and scalar perturbations are generated by the same scalar inflation.
NASA Astrophysics Data System (ADS)
Singh, Avneet; Papa, Maria Alessandra; Eggenstein, Heinz-Bernd; Zhu, Sylvia; Pletsch, Holger; Allen, Bruce; Bock, Oliver; Maschenchalk, Bernd; Prix, Reinhard; Siemens, Xavier
2016-09-01
We present results of a high-frequency all-sky search for continuous gravitational waves from isolated compact objects in LIGO's fifth science run (S5) data, using the computing power of the Einstein@Home volunteer computing project. This is the only dedicated continuous gravitational wave search that probes this high-frequency range on S5 data. We find no significant candidate signal, so we set 90% confidence level upper limits on continuous gravitational wave strain amplitudes. At the lower end of the search frequency range, around 1250 Hz, the most constraining upper limit is 5.0 ×10-24, while at the higher end, around 1500 Hz, it is 6.2 ×10-24. Based on these upper limits, and assuming a fiducial value of the principal moment of inertia of 1038 kg m2 , we can exclude objects with ellipticities higher than roughly 2.8 ×10-7 within 100 pc of Earth with rotation periods between 1.3 and 1.6 milliseconds.
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.
High-frequency Rayleigh-wave method
Xia, J.; Miller, R.D.; Xu, Y.; Luo, Y.; Chen, C.; Liu, J.; Ivanov, J.; Zeng, C.
2009-01-01
High-frequency (???2 Hz) Rayleigh-wave data acquired with a multichannel recording system have been utilized to determine shear (S)-wave velocities in near-surface geophysics since the early 1980s. This overview article discusses the main research results of high-frequency surface-wave techniques achieved by research groups at the Kansas Geological Survey and China University of Geosciences in the last 15 years. The multichannel analysis of surface wave (MASW) method is a non-invasive acoustic approach to estimate near-surface S-wave velocity. The differences between MASW results and direct borehole measurements are approximately 15% or less and random. Studies show that simultaneous inversion with higher modes and the fundamental mode can increase model resolution and an investigation depth. The other important seismic property, quality factor (Q), can also be estimated with the MASW method by inverting attenuation coefficients of Rayleigh waves. An inverted model (S-wave velocity or Q) obtained using a damped least-squares method can be assessed by an optimal damping vector in a vicinity of the inverted model determined by an objective function, which is the trace of a weighted sum of model-resolution and model-covariance matrices. Current developments include modeling high-frequency Rayleigh-waves in near-surface media, which builds a foundation for shallow seismic or Rayleigh-wave inversion in the time-offset domain; imaging dispersive energy with high resolution in the frequency-velocity domain and possibly with data in an arbitrary acquisition geometry, which opens a door for 3D surface-wave techniques; and successfully separating surface-wave modes, which provides a valuable tool to perform S-wave velocity profiling with high-horizontal resolution. ?? China University of Geosciences (Wuhan) and Springer-Verlag GmbH 2009.
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.
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 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.
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.
NASA Astrophysics Data System (ADS)
Fontana, Giorgio
2005-02-01
There is only one experimental proof that gravitational waves exist. With such a limitation, it may seem premature to suggest the possibility that gravitational waves can became a preferred space propulsion technique. The present understanding of the problem indicates that this is not the case. The emission of gravitational waves from astrophysical sources has been confirmed by observation, the respective detection at large distance from the source is difficult and actually we have no confirmation of a successful detection. Therefore the required preliminary discovery has been already made. This opinion is enforced by many different proposals for building the required powerful gravitational wave generators that have recently appeared in the literature and discussed at conferences. It is no longer reasonable to wait for additional confirmation of the existence of gravitational waves to start a program for building generators and testing their possible application to space travel. A vast literature shows that gravitational waves can be employed for space propulsion. Gravitational wave rockets have been proposed, non-linearity of Einstein equations allows the conversion of gravitational waves to a static gravitational field and ``artificial gravity assist'' may become a new way of travelling in space-time. Different approaches to gravitational wave propulsion are reviewed and compared. Gravitational wave propulsion is also compared to traditional rocket propulsion and an undeniable advantage can be demonstrated in terms of efficiency and performance. Testing the predictions will require gravitational wave generators with high power and wavelength short enough for producing high energy densities. Detectors designed for the specific application must be developed, taking into account that non-linearity effects are expected. The study and development of Gravitational wave propulsion is a very challenging endeavor, involving the most complex theories, sophisticated
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.
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 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.
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.
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)
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.
High-frequency matrix converter with square wave input
Carr, Joseph Alexander; Balda, Juan Carlos
2015-03-31
A device for producing an alternating current output voltage from a high-frequency, square-wave input voltage comprising, high-frequency, square-wave input a matrix converter and a control system. The matrix converter comprises a plurality of electrical switches. The high-frequency input and the matrix converter are electrically connected to each other. The control system is connected to each switch of the matrix converter. The control system is electrically connected to the input of the matrix converter. The control system is configured to operate each electrical switch of the matrix converter converting a high-frequency, square-wave input voltage across the first input port of the matrix converter and the second input port of the matrix converter to an alternating current output voltage at the output of the matrix converter.
NASA Astrophysics Data System (ADS)
seyithocuk; jjeherrera; eltodesukane; GrahamRounce; rloldershaw; Beaker, Dr; Sandhu, G. S.; Ophiuchi
2016-03-01
In reply to the news article on the LIGO collaboration's groundbreaking detection of gravitational waves, first predicted by Einstein 100 years ago, from two black holes colliding (pp5, 6-7 and http://ow.ly/Ylsyt).
Gravitational lens time delays and gravitational waves
Frieman, J.A. Department of Astronomy Astrophysics, University of Chicago, Chicago, Illinois 60637 ); Harari, D.D.; Surpi, G.C. )
1994-10-15
Using Fermat's principle, we analyze the effects of very long wavelength gravitational waves upon the images of a gravitationally lensed quasar. We show that the lens equation in the presence of gravity waves is equivalent to that of a lens with a different alignment between source, deflector, and observer in the absence of gravity waves. Contrary to a recent claim, we conclude that measurements of time delays in gravitational lenses cannot serve as a method to detect or constrain a stochastic background of gravitational waves of cosmological wavelengths, because the wave-induced time delay is observationally indistinguishable from an intrinsic time delay due to the lens geometry.
High frequency single mode traveling wave structure for particle acceleration
NASA Astrophysics Data System (ADS)
Ivanyan, M. I.; Danielyan, V. A.; Grigoryan, B. A.; Grigoryan, A. H.; Tsakanian, A. V.; Tsakanov, V. M.; Vardanyan, A. S.; Zakaryan, S. V.
2016-09-01
The development of the new high frequency slow traveling wave structures is one of the promising directions in accomplishment of charged particles high acceleration gradient. The disc and dielectric loaded structures are the most known structures with slowly propagating modes. In this paper a large aperture high frequency metallic two-layer accelerating structure is studied. The electrodynamical properties of the slowly propagating TM01 mode in a metallic tube with internally coated low conductive thin layer are examined.
NASA Astrophysics Data System (ADS)
Mottola, Emil
2016-03-01
General Relativity receives quantum corrections relevant at macroscopic distance scales and near event horizons. These arise from the conformal scalar degree of freedom in the extended effective field theory (EFT) of gravity generated by the trace anomaly of massless quantum fields in curved space. Linearized around flat space this quantum scalar degree of freedom combines with the conformal part of the metric and predicts the existence of scalar spin-0 ``breather'' propagating gravitational waves in addition to the transverse tensor spin-2 waves of classical General Relativity. Estimates of the expected strength of scalar gravitational radiation from compact astrophysical sources are given.
Gravitational Waves and Time-Domain Astronomy
NASA Astrophysics Data System (ADS)
Centrella, Joan; Nissanke, Samaya; Williams, Roy
2012-04-01
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 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.
Sources of gravitational waves
NASA Technical Reports Server (NTRS)
Schutz, Bernard F.
1989-01-01
Sources of low frequency gravitational radiation are reviewed from an astrophysical point of view. Cosmological sources include the formation of massive black holes in galactic nuclei, the capture by such holes of neutron stars, the coalescence of orbiting pairs of giant black holes, and various means of producing a stochastic background of gravitational waves in the early universe. Sources local to our Galaxy include various kinds of close binaries and coalescing binaries. Gravitational wave astronomy can provide information that no other form of observing can supply; in particular, the positive identification of a cosmological background originating in the early universe would be an event as significant as was the detection of the cosmic microwave background.
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)
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.
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.
High-frequency shear-horizontal surface acoustic wave sensor
Branch, Darren W
2013-05-07
A Love wave sensor uses a single-phase unidirectional interdigital transducer (IDT) on a piezoelectric substrate for leaky surface acoustic wave generation. The IDT design minimizes propagation losses, bulk wave interferences, provides a highly linear phase response, and eliminates the need for impedance matching. As an example, a high frequency (.about.300-400 MHz) surface acoustic wave (SAW) transducer enables efficient excitation of shear-horizontal waves on 36.degree. Y-cut lithium tantalate (LTO) giving a highly linear phase response (2.8.degree. P-P). The sensor has the ability to detect at the pg/mm.sup.2 level and can perform multi-analyte detection in real-time. The sensor can be used for rapid autonomous detection of pathogenic microorganisms and bioagents by field deployable platforms.
High-frequency shear-horizontal surface acoustic wave sensor
Branch, Darren W
2014-03-11
A Love wave sensor uses a single-phase unidirectional interdigital transducer (IDT) on a piezoelectric substrate for leaky surface acoustic wave generation. The IDT design minimizes propagation losses, bulk wave interferences, provides a highly linear phase response, and eliminates the need for impedance matching. As an example, a high frequency (.about.300-400 MHz) surface acoustic wave (SAW) transducer enables efficient excitation of shear-horizontal waves on 36.degree. Y-cut lithium tantalate (LTO) giving a highly linear phase response (2.8.degree. P-P). The sensor has the ability to detect at the pg/mm.sup.2 level and can perform multi-analyte detection in real-time. The sensor can be used for rapid autonomous detection of pathogenic microorganisms and bioagents by field deployable platforms.
Corrosion monitoring using high-frequency guided ultrasonic waves
NASA Astrophysics Data System (ADS)
Fromme, Paul
2014-02-01
Corrosion develops due to adverse environmental conditions during the life cycle of a range of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the structural integrity. The nondestructive detection and monitoring of corrosion damage in difficult to access areas can be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, guided wave modes were generated that penetrate through the complete thickness of the structure. The wave propagation and interference of the different guided wave modes depends on the thickness of the structure. Laboratory experiments were conducted and the wall thickness reduced by consecutive milling of the steel structure. Further measurements were conducted using accelerated corrosion in a salt water bath and the damage severity monitored. From the measured signal change due to the wave mode interference the wall thickness reduction was monitored. The high frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.
Corrosion monitoring using high-frequency guided waves
NASA Astrophysics Data System (ADS)
Fromme, P.
2016-04-01
Corrosion can develop due to adverse environmental conditions during the life cycle of a range of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Generalized corrosion leading to wall thickness loss can cause the reduction of the strength and thus degradation of the structural integrity. The monitoring of corrosion damage in difficult to access areas can be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic wedge transducers with single sided access to the structure, guided wave modes were selectively generated that penetrate through the complete thickness of the structure. The wave propagation and interference of the different guided wave modes depends on the thickness of the structure. Laboratory experiments were conducted for wall thickness reduction due to milling of the steel structure. From the measured signal changes due to the wave mode interference the reduced wall thickness was monitored. Good agreement with theoretical predictions was achieved. The high frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.
Sensitivity of high-frequency Rayleigh-wave data revisited
Xia, J.; Miller, R.D.; Ivanov, J.
2007-01-01
Rayleigh-wave phase velocity of a layered earth model is a function of frequency and four groups of earth properties: P-wave velocity, S-wave velocity (Vs), density, and thickness of layers. Analysis of the Jacobian matrix (or the difference method) provides a measure of dispersion curve sensitivity to earth properties. Vs is the dominant influence for the fundamental mode (Xia et al., 1999) and higher modes (Xia et al., 2003) of dispersion curves in a high frequency range (>2 Hz) followed by layer thickness. These characteristics are the foundation of determining S-wave velocities by inversion of Rayleigh-wave data. More applications of surface-wave techniques show an anomalous velocity layer such as a high-velocity layer (HVL) or a low-velocity layer (LVL) commonly exists in near-surface materials. Spatial location (depth) of an anomalous layer is usually the most important information that surface-wave techniques are asked to provide. Understanding and correctly defining the sensitivity of high-frequency Rayleigh-wave data due to depth of an anomalous velocity layer are crucial in applying surface-wave techniques to obtain a Vs profile and/or determine the depth of an anomalous layer. Because depth is not a direct earth property of a layered model, changes in depth will result in changes in other properties. Modeling results show that sensitivity at a given depth calculated by the difference method is dependent on the Vs difference (contrast) between an anomalous layer and surrounding layers. The larger the contrast is, the higher the sensitivity due to depth of the layer. Therefore, the Vs contrast is a dominant contributor to sensitivity of Rayleigh-wave data due to depth of an anomalous layer. Modeling results also suggest that the most sensitive depth for an HVL is at about the middle of the depth to the half-space, but for an LVL it is near the ground surface. ?? 2007 Society of Exploration Geophysicists.
Generation of sheet currents by high frequency fast MHD waves
NASA Astrophysics Data System (ADS)
Núñez, Manuel
2016-07-01
The evolution of fast magnetosonic waves of high frequency propagating into an axisymmetric equilibrium plasma is studied. By using the methods of weakly nonlinear geometrical optics, it is shown that the perturbation travels in the equatorial plane while satisfying a transport equation which enables us to predict the time and location of formation of shock waves. For plasmas of large magnetic Prandtl number, this would result into the creation of sheet currents which may give rise to magnetic reconnection and destruction of the original equilibrium.
Gravitational wave bursts from cosmic strings
Damour; Vilenkin
2000-10-30
Cusps of cosmic strings emit strong beams of high-frequency gravitational waves (GW). As a consequence of these beams, the stochastic ensemble of gravitational waves generated by a cosmological network of oscillating loops is strongly non-Gaussian, and includes occasional sharp bursts that stand above the rms GW background. These bursts might be detectable by the planned GW detectors LIGO/VIRGO and LISA for string tensions as small as G&mgr; approximately 10(-13). The GW bursts discussed here might be accompanied by gamma ray bursts. PMID:11041921
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.
High-frequency wave normals in the solar wind
Herbert, F.; Smith, L.D.; Sonett, C.P.
1984-05-01
High-frequency (0.01--0.04 Hz) magnetic fluctuations in 506 ten-minute intervals of contemporaneous Explorer 35 and Apollo 12 measurements made in the solar wind near the morning side of the Earth's bow shock show the presence of a large population of disturbances resembling Alfven waves. Each wavefront normal n is systematically aligned (median deviation = 35/sup 0/) with , the associated ten-minute average of the magnetic field. Because of variability in the direction of from one interval to another, the coupled distribution of n is nearly isotropic in solar ecliptic coordinates, in contrast with the results of other studies of waves at much lower frequency indicating outward propagation from the sun. Presumably the high frequency waves discussed here are stirred into isotropy (in solar ecliptic coordinates) by following the low frequency fluctuations. As these waves maintain their alignement of n with despite the great variation of , a strong physical alignment constraint is inferred.
Transformation ray method: controlling high frequency elastic waves (L).
Chang, Zheng; Liu, Xiaoning; Hu, Gengkai; Hu, Jin
2012-10-01
Elastic ray theory is a high frequency asymptotic approximation of solution of elastodynamic equation, and is widely used in seismology. In this paper, the form invariance under a general spatial mapping and high frequency wave control have been examined by transformation method. It is showed that with the constraint of major and minor symmetry of the transformed elastic tensor, the eikonal equation keeps its form under a general mapping, however, the transport equation loses its form except for conformal mapping. Therefore, the elastic ray path can be controlled in an exact manner by a transformation method, whereas energy distribution along the ray is only approximately controlled. An elastic rotator based on ray tracing method is also provided to illustrate the method and to access the approximation. PMID:23039561
High-frequency homogenization for travelling waves in periodic media
NASA Astrophysics Data System (ADS)
Harutyunyan, Davit; Milton, Graeme W.; Craster, Richard V.
2016-07-01
We consider high-frequency homogenization in periodic media for travelling waves of several different equations: the wave equation for scalar-valued waves such as acoustics; the wave equation for vector-valued waves such as electromagnetism and elasticity; and a system that encompasses the Schrödinger equation. This homogenization applies when the wavelength is of the order of the size of the medium periodicity cell. The travelling wave is assumed to be the sum of two waves: a modulated Bloch carrier wave having crystal wavevector k and frequency ω1 plus a modulated Bloch carrier wave having crystal wavevector m and frequency ω2. We derive effective equations for the modulating functions, and then prove that there is no coupling in the effective equations between the two different waves both in the scalar and the system cases. To be precise, we prove that there is no coupling unless ω1=ω2 and (k -m )⊙Λ ∈2 π Zd, where Λ=(λ1λ2…λd) is the periodicity cell of the medium and for any two vectors a =(a1,a2,…,ad),b =(b1,b2,…,bd)∈Rd, the product a⊙b is defined to be the vector (a1b1,a2b2,…,adbd). This last condition forces the carrier waves to be equivalent Bloch waves meaning that the coupling constants in the system of effective equations vanish. We use two-scale analysis and some new weak-convergence type lemmas. The analysis is not at the same level of rigour as that of Allaire and co-workers who use two-scale convergence theory to treat the problem, but has the advantage of simplicity which will allow it to be easily extended to the case where there is degeneracy of the Bloch eigenvalue.
The Detection of Gravitational Waves
NASA Astrophysics Data System (ADS)
Blair, David G.
2005-10-01
Part I. An Introduction to Gravitational Waves and Methods for their Detection: 1. Gravitational waves in general relativity D. G. Blair; 2. Sources of gravitational waves D. G. Blair; 3. Gravitational wave detectors D. G. Blair; Part II. Gravitational Wave Detectors: 4. Resonant-bar detectors D. G. Blair; 5. Gravity wave dewars W. O. Hamilton; 6. Internal friction in high Q materials J. Ferreirinko; 7. Motion amplifiers and passive transducers J. P. Richard; 8. Parametric transducers P. J. Veitch; 9. Detection of continuous waves K. Tsubono; 10. Data analysis and algorithms for gravitational wave-antennas G. V. Paalottino; Part III. Laser Interferometer Antennas: 11. A Michelson interferometer using delay lines W. Winkler; 12. Fabry-Perot cavity gravity-wave detectors R. W. P. Drever; 13. The stabilisation of lasers for interferometric gravitational wave detectors J. Hough; 14. Vibration isolation for the test masses in interferometric gravitational wave detectors N. A. Robertson; 15. Advanced techniques A. Brillet; 16. Data processing, analysis and storage for interferometric antennas B. F. Schutz; 17. Gravitational wave detection at low and very low frequencies R. W. Hellings.
High frequency seismic waves and slab structures beneath Italy
NASA Astrophysics Data System (ADS)
Sun, Daoyuan; Miller, Meghan S.; Piana Agostinetti, Nicola; Asimow, Paul D.; Li, Dunzhu
2014-04-01
Tomographic images indicate a complicated subducted slab structure beneath the central Mediterranean where gaps in fast velocity anomalies in the upper mantle are interpreted as slab tears. The detailed shape and location of these tears are important for kinematic reconstructions and understanding the evolution of the subduction system. However, tomographic images, which are produced by smoothed, damped inversions, will underestimate the sharpness of the structures. Here, we use the records from the Italian National Seismic Network (IV) to study the detailed slab structure. The waveform records for stations in Calabria show large amplitude, high frequency (f>5 Hz) late arrivals with long coda after a relatively low-frequency onset for both P and S waves. In contrast, the stations in the southern and central Apennines lack such high frequency arrivals, which correlate spatially with the central Apennines slab window inferred from tomography and receiver function studies. Thus, studying the high frequency arrivals provides an effective way to investigate the structure of slab and detect possible slab tears. The observed high frequency arrivals in the southern Italy are the strongest for events from 300 km depth and greater whose hypocenters are located within the slab inferred from fast P-wave velocity perturbations. This characteristic behavior agrees with previous studies from other tectonic regions, suggesting the high frequency energy is generated by small scale heterogeneities within the slab which act as scatterers. Furthermore, using a 2-D finite difference (FD) code, we calculate synthetic seismograms to search for the scale, shape and velocity perturbations of the heterogeneities that may explain features observed in the data. Our preferred model of the slab heterogeneities beneath the Tyrrhenian Sea has laminar structure parallel to the slab dip and can be described by a von Kármán function with a down-dip correlation length of 10 km and 0.5 km in
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
Quantum Emulation of Gravitational Waves
NASA Astrophysics Data System (ADS)
Fernandez-Corbaton, Ivan; Cirio, Mauro; Büse, Alexander; Lamata, Lucas; Solano, Enrique; Molina-Terriza, Gabriel
2015-07-01
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.
Quantum Emulation of Gravitational Waves.
Fernandez-Corbaton, Ivan; Cirio, Mauro; Büse, Alexander; Lamata, Lucas; Solano, Enrique; Molina-Terriza, Gabriel
2015-07-14
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.
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
High-frequency P wave spectra from explosions and earthquakes
NASA Astrophysics Data System (ADS)
Walter, William R.; Priestley, Keith F.
Two explosion P wave spectral models [Sharpe, 1942; Mueller-Murphy, 1971] and two earthquake P wave spectral models [Archambeau, 1968, 1972; modified Brune 1970, 1971] are reviewed to assess their implications for high-frequency (>1 Hz) seismic discrimination between earthquakes and explosions. The importance of the corner frequency scaling, particularly for models with the same high-frequency spectral decay rate, is demonstrated by calculating source spectral ratios (a potentially important regional discriminant) for these models. We compare North American events and a limited data set of Central Asian events with these spectral models. We find North American earthquakes are consistent with a constant stress drop modified Brune model between 10 and 30 Hz. Shallow (<700 m depth) Pahute Mesa explosions at the Nevada Test Site have a high-frequency spectral decay between 10 and 30 Hz greater than the ω-2 predicted by the explosion models. Near regional recordings of the Soviet Joint Verification Experiment (JVE) explosion show a higher corner frequency and lower 1 to 4 Hz spectral ratios than predicted by either explosion model. The higher corner frequency of the Soviet JVE appears not to be due to attenuation, or receiver effects, and may represent a need for different corner frequency scaling, or result from source complications such as spall and tectonic release. A regional recording of the Soviet JVE (NEIC mb = 6.1) is shown to have a lower 1 to 4 Hz spectral ratio than a smaller earthquake (NEIC mb = 4.6) recorded on a nearly reciprocal path.
High-Frequency Wave Propagation by the Segment Projection Method
NASA Astrophysics Data System (ADS)
Engquist, Björn; Runborg, Olof; Tornberg, Anna-Karin
2002-05-01
Geometrical optics is a standard technique used for the approximation of high-frequency wave propagation. Computational methods based on partial differential equations instead of the traditional ray tracing have recently been applied to geometrical optics. These new methods have a number of advantages but typically exhibit difficulties with linear superposition of waves. In this paper we introduce a new partial differential technique based on the segment projection method in phase space. The superposition problem is perfectly resolved and so is the problem of computing amplitudes in the neighborhood of caustics. The computational complexity is of the same order as that of ray tracing. The new algorithm is described and a number of computational examples are given, including a simulation of waveguides.
High-frequency electrostatic waves in the magnetosphere.
NASA Technical Reports Server (NTRS)
Young, T. S. T.
1973-01-01
High-frequency electrostatic microinstabilities in magnetospheric plasmas are considered in detail. Rather special plasma parameters are found to be required to match the theoretical wave spectrum with satellite observations in the magnetosphere. In particular, it is necessary to have a cold and a warm species of electrons such that (1) the warm component has an anomalous velocity distribution function that is nonmonotonic in the perpendicular component of velocity and is the source of free energy driving the instabilities, (2) the density ratio of the cold component to the hot component is greater than about 0.01, and (3) the temperature ratio of the two components for cases of high particle density is no less than 0.1. These requirements and the corresponding instability criteria are satisfied only in the trapping region; this is also the region in which the waves are most frequently observed. The range of unstable wavelengths and an estimate of the diffusion coefficient are also obtained. The wave are found to induce strong diffusion in velocity space for low-energy electrons during periods of moderate wave amplitude.
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 Wave Experiments - Proceedings of the First Edoardo Amaldi Conference
NASA Astrophysics Data System (ADS)
Coccia, E.; Pizzella, G.; Ronga, F.
1995-07-01
Production of Gravitational Radiation by Particle Accelerators and by High Power Lasers * NESTOR: An Underwater Cerenkov Detector for Neutrino Astronomy * A Cosmic-Ray Veto System for the Gravitational Wave Detector NAUTLUS * Interferometers * Development of a 20m Prototype Laser Interferometric Gravitational Wave Detector at NAO * Production of Higher-Order Light Modes by High Quality Optical Components * Vibration Isolation and Suspension Systems for Laser Interferometer Gravitational Wave Detectors * Quality Factors of Stainless Steel Pendulum Wires * Reduction of Suspension Thermal Noises in Laser Free Masses Gravitational Antenna by Correlation of the Output with Additional Optical Signal * Resonant Detectors * Regeneration Effects in a Resonant Gravitational Wave Detector * A Cryogenic Sapphire Transducer with Double Frequency Pumping for Resonant Mass GW Detectors * Effect of Parametric Instability of Gravitational Wave Antenna with Microwave Cavity Transducer * Resonators of Novel Geometry for Large Mass Resonant Transducers * Measurements on the Gravitational Wave Antenna ALTAIR Equipped with a BAE Transducer * The Rome BAE Transducer: Perspectives of its Application to Ultracryogenic Gravitational Wave Antennas * Behavior of a de SQUID Tightly Coupled to a High-Q Resonant Transducer * High Q-Factor LC Resonators for Optimal Coupling * Comparison Between Different Data Analysis Procedures for Gravitational Wave Pulse Detection * Supernova 1987A Rome Maryland Gravitational Radiation Antenna Observations * Analysis of the Data Recorded by the Maryland and Rome Gravitational-Wave Detectors and the Seismic Data from Moscow and Obninsk Station during SN1987A * Multitransducer Resonant Gravitational Antennas * Local Array of High Frequency Antennas * Interaction Cross-Sections for Spherical Resonant GW Antennae * Signal-To-Noise Analysis for a Spherical Gravitational Wave Antenna Instrumented with Multiple Transducers * On the Design of Ultralow Temperature Spherical
Quantum Opportunities in Gravitational Wave Detectors
Mavalvala, Negris
2012-03-14
Direct observation of gravitational waves should open a new window into the Universe. Gravitational wave detectors are the most sensitive position meters ever constructed. The quantum limit in gravitational wave detectors opens up a whole new field of study. Quantum opportunities in gravitational wave detectors include applications of quantum optics techniques and new tools for quantum measurement on truly macroscopic (human) scales.
Geometrical versus wave optics under gravitational waves
NASA Astrophysics Data System (ADS)
Angélil, Raymond; Saha, Prasenjit
2015-06-01
We present some new derivations of the effect of a plane gravitational wave on a light ray. A simple interpretation of the results is that a gravitational wave causes a phase modulation of electromagnetic waves. We arrive at this picture from two contrasting directions, namely, null geodesics and Maxwell's equations, or geometric and wave optics. Under geometric optics, we express the geodesic equations in Hamiltonian form and solve perturbatively for the effect of gravitational waves. We find that the well-known time-delay formula for light generalizes trivially to massive particles. We also recover, by way of a Hamilton-Jacobi equation, the phase modulation obtained under wave optics. Turning then to wave optics—rather than solving Maxwell's equations directly for the fields, as in most previous approaches—we derive a perturbed wave equation (perturbed by the gravitational wave) for the electromagnetic four-potential. From this wave equation it follows that the four-potential and the electric and magnetic fields all experience the same phase modulation. Applying such a phase modulation to a superposition of plane waves corresponding to a Gaussian wave packet leads to time delays.
Multibaseline gravitational wave radiometry
Talukder, Dipongkar; Bose, Sukanta; Mitra, Sanjit
2011-03-15
We present a statistic for the detection of stochastic gravitational wave backgrounds (SGWBs) using radiometry with a network of multiple baselines. We also quantitatively compare the sensitivities of existing baselines and their network to SGWBs. We assess how the measurement accuracy of signal parameters, e.g., the sky position of a localized source, can improve when using a network of baselines, as compared to any of the single participating baselines. The search statistic itself is derived from the likelihood ratio of the cross correlation of the data across all possible baselines in a detector network and is optimal in Gaussian noise. Specifically, it is the likelihood ratio maximized over the strength of the SGWB and is called the maximized-likelihood ratio (MLR). One of the main advantages of using the MLR over past search strategies for inferring the presence or absence of a signal is that the former does not require the deconvolution of the cross correlation statistic. Therefore, it does not suffer from errors inherent to the deconvolution procedure and is especially useful for detecting weak sources. In the limit of a single baseline, it reduces to the detection statistic studied by Ballmer [Classical Quantum Gravity 23, S179 (2006).] and Mitra et al.[Phys. Rev. D 77, 042002 (2008).]. Unlike past studies, here the MLR statistic enables us to compare quantitatively the performances of a variety of baselines searching for a SGWB signal in (simulated) data. Although we use simulated noise and SGWB signals for making these comparisons, our method can be straightforwardly applied on real data.
Comparing the Robustness of High-Frequency Traveling-Wave Tube Slow-Wave Circuits
NASA Technical Reports Server (NTRS)
Chevalier, Christine T.; Wilson, Jeffrey D.; Kory, Carol L.
2007-01-01
A three-dimensional electromagnetic field simulation software package was used to compute the cold-test parameters, phase velocity, on-axis interaction impedance, and attenuation, for several high-frequency traveling-wave tube slow-wave circuit geometries. This research effort determined the effects of variations in circuit dimensions on cold-test performance. The parameter variations were based on the tolerances of conventional micromachining techniques.
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.
Utilization of high-frequency Rayleigh waves in near-surface geophysics
Xia, J.; Miller, R.D.; Park, C.B.; Ivanov, J.; Tian, G.; Chen, C.
2004-01-01
Shear-wave velocities can be derived from inverting the dispersive phase velocity of the surface. The multichannel analysis of surface waves (MASW) is one technique for inverting high-frequency Rayleigh waves. The process includes acquisition of high-frequency broad-band Rayleigh waves, efficient and accurate algorithms designed to extract Rayleigh-wave dispersion curves from Rayleigh waves, and stable and efficient inversion algorithms to obtain near-surface S-wave velocity profiles. MASW estimates S-wave velocity from multichannel vertical compoent data and consists of data acquisition, dispersion-curve picking, and inversion.
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.
The Detection of Gravitational Waves
NASA Astrophysics Data System (ADS)
Braccini, Stefano; Fidecaro, Francesco
The detection of gravitational waves is challenging researchers since half a century. The relative precision required, 10^{-21}, is difficult to imagine, this is 10^{-5} the diameter of a proton over several kilometres, using masses of tens of kilograms, or picometres over millions of kilometres. A theoretical description of gravitational radiation and its effects on matter, all consequence of the general theory of relativity, is given. Then the astrophysical phenomena that are candidates of gravitational wave emission are discussed, considering also amplitudes and rates. The binary neutron star system PSR1913+16, which provided the first evidence for energy loss by gravitational radiation in 1975, is briefly discussed. Then comes a description of the experimental developments, starting with ground-based interferometers, their working principles and their most important sources of noise. The earth-wide network that is being built describes how these instruments will be used in the observation era. Several other detection techniques, such as space interferometry, pulsar timing arrays and resonant detectors, covering different bands of the gravitational wave frequency spectrum complete these lectures.
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.
High-frequency acoustic waves are not sufficient to heat the solar chromosphere.
Fossum, Astrid; Carlsson, Mats
2005-06-16
One of the main unanswered questions in solar physics is why the Sun's outer atmosphere is hotter than its surface. Theory predicts abundant production of high-frequency (10-50 mHz) acoustic waves in subsurface layers of the Sun, and such waves are believed by many to constitute the dominant heating mechanism of the chromosphere (the lower part of the outer solar atmosphere) in non-magnetic regions. Such high-frequency waves are difficult to detect because of high-frequency disturbances in Earth's atmosphere (seeing) and other factors. Here we report the detection of high-frequency waves, and we use numerical simulations to show that the acoustic energy flux of these waves is too low, by a factor of at least ten, to balance the radiative losses in the solar chromosphere. Acoustic waves therefore cannot constitute the dominant heating mechanism of the solar chromosphere. PMID:15959510
High-frequency electrostatic waves near earth's bow shock
NASA Technical Reports Server (NTRS)
Onsager, T. G.; Holzworth, R. H.; Koons, H. C.; Bauer, O. H.; Gurnett, D. A.
1989-01-01
Electrostatic wave measurements from the Active Magnetospheric Particle Tracer Explorer Ion Release Module have been used to investigate the wave modes and their possible generation mechanisms in the earth's bow shock and magnetosheath. It is demonstrated that electrostatic waves are present in the bow shock and magnetosheath with frequencies above the maximum frequency for Doppler-shifted ion acoustic waves, yet below the plasma frequency. Waves in this frequency range are tentatively identified as electron beam mode waves. Data from 45 bow shock crossings are then used to investigate possible correlations between the electrostatic wave properties and the near-shock plasma parameters. The most significant relationships found are anticorrelations with Alfven Mach number and electron beta. Mechanisms which might produce electron beams in the shock and magnetosheath are discussed in terms of the correlation study results. These mechanisms include acceleration by the cross-shock electric field and by lower hybrid frequency waves. A magnetosheath 'time of flight' mechanism, in analogy to the electron foreshock region, is introduced as another possible beam generation mechanism.
High-Frequency Coupling to Cables for Plane Wave and Random Wave Conditions
NASA Astrophysics Data System (ADS)
Pissoort, D.; Vanhee, F.; Boesman, B.; Catrysse, J.; Vandenbosch, G.; Gielen, G.
2012-05-01
In this paper, the high-frequency coupling from electromagnetic fields to cables is studied and this under (i) plane-wave conditions representing a susceptibility test in a semi-anechoic room and (ii) random wave conditions representing a more realistic environment with many reflections. Two set-ups are considered. First, a s imple wire above an infinite ground plane. Second, a more realistic set-up representing a desktop device with attached cables whose layout is according to EN 55016-2-3:2006 [1]. It is shown that for frequencies above 1 GHz the induced (worst-case) current at the side of the device under test can differ significantly between plane-wave and random wave conditions. Moreover, the random wave condition does necessarily not lead to the highest induced currents.
NASA Astrophysics Data System (ADS)
Mukhter, A.; Singh, N.; Khazanov, G.
2006-12-01
Satellite observations in the auroral plasma have revealed that extremely low frequency (ELF) waves play a dominant role in the acceleration of electrons and ions in the auroral plasma. The electromagnetic components of the ELF (EMELF) waves are the electromagnetic ion cyclotron (EMIC) waves below the cyclotron frequency of the lightest ion species in a multi-ion plasma. Shear Alfvén waves (SAWs) constitute the lowest frequency components of the ELF waves below the ion cyclotron frequency of the heaviest ion. The mechanism for the transfer of energy from such EMELF waves to ions affecting transverse ion heating still remains a matter of debate. A very ubiquitous feature of ELF waves now observed in several rocket and satellite experiments is that they occur in conjunction with high-frequency electrostatic waves. The frequency spectrum of the composite wave turbulence extends from the low frequency of the Alfvénic waves to the high frequency of proton plasma frequency and/or the lower hybrid frequency. The spectrum does not show any feature organized by the ion cyclotron frequencies and their harmonics. Such broadband waves consisting of both the EM and ES waves are now popularly referred as BBELF waves. We present results here from 2.5-D particle-in- cell simulations showing that the ES components are directly generated by cross-field plasma instabilities driven by the drifts of the ions and electrons in the EM component of the BBELF waves. We also demonstrate that the ES wave generation is directly involved in the transverse acceleration of ions (TAI) as commonly measured with the BBELF wave events. In the simulation we drive the plasma by the transverse electric field, Ey, of the EM waves; the frequency of Ey is varied from a frequency below the heavy ion cyclotron frequency to below the light ion cyclotron frequency. We have also performed simulations for Ey having a continuous spectrum given by a power law with different spectral indexes. The driving electric
Effect of near-surface topography on high-frequency Rayleigh-wave propagation
NASA Astrophysics Data System (ADS)
Wang, Limin; Xu, Yixian; Xia, Jianghai; Luo, Yinhe
2015-05-01
Rayleigh waves, which are formed due to interference of P- and Sv-waves near the free surface, propagate along the free surface and vanish exponentially in the vertical direction. Their propagation is strongly influenced by surface topography. Due to the high resolution and precision requirements of near-surface investigations, the high-frequency Rayleigh waves are usually used for near-surface structural detecting. Although there are some numerical studies on high-frequency Rayleigh-wave propagation on topographic free surface, detailed analysis of characters of high-frequency Rayleigh-wave propagation on topographic free surface remains untouched. Hence, research of propagation of Rayleigh waves on complex topographic surface becomes critical for Rayleigh-wave methods in near-surface applications. To study the propagation of high-frequency Rayleigh waves on topographic free surface, two main topographic models are designed in this study. One of the models contains a depressed topographic surface, and another contains an uplifted topographic surface. We numerically simulate the propagation of high-frequency Rayleigh waves on these two topographic surfaces by finite-difference method. Soon afterwards, we analyze the propagation character of high-frequency Rayleigh waves on such topographic models, and compare the variations on its energy and frequency before and after passing the topographic region. At last, we discuss the relationship between the variations and topographical steepness of each model. Our numerical results indicate that influence of depressed topography for high-frequency Rayleigh waves is more distinct than influence of uplifted topography. Rayleigh waves produce new scattering body waves during passing the depressed topography with reduction of amplitude and loss of high-frequency components. Moreover, the steeper the depressed topography is, the more energy of Rayleigh waves is lost. The uplifted topography with gentle slope produces similar
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.
Attenuation of high-frequency seismic waves in northeast India
NASA Astrophysics Data System (ADS)
Padhy, Simanchal; Subhadra, N.
2010-04-01
We studied attenuation of S and coda waves, their frequency and lapse time dependencies in northeast India in the frequency range of 1-24 Hz. We adopted theories of both single and multiple scattering to bandpass-filtered seismograms to fit coda envelopes to estimate Q for coda waves (QC) and Q for S-waves (QS) at five central frequencies of 1.5, 3, 6, 12 and 24 Hz. The selected data set consists of 182 seismograms recorded at ten seismic stations within epicentral distance of 22-300 km in the local magnitude range of 2.5-5.2. We found that with the increase in lapse time window from 40 to 60 s, Q0 (QC at 1 Hz) increases from 213 to 278, while the frequency dependent coefficient n decreases from 0.89 to 0.79. Both QC and QS increase with frequency. The average value of QS obtained by using coda normalization method for NE India has the power law form of (96.8 +/- 21.5)f(1.03+/-0.04) in 1-24 Hz. We adopted energy flux model (EFM) and diffusion model for the multiple scattered wave energy in three-dimensions. The results show that the contribution of multiple scattering dominates for longer lapse time close to or larger than mean free time of about 60 s. The estimates of QC are overestimated at longer lapse time by neglecting the effects of multiple scattering. Some discrepancies have been observed between the theoretical predictions and the observations, the difference could be due to the approximation of the uniform medium especially at large hypocentral distances. Increase in QC with lapse time can be explained as the result of the depth dependent attenuation properties and multiple scattering effect.
Accumulative coupling between magnetized tenuous plasma and gravitational waves
NASA Astrophysics Data System (ADS)
Zhang, Fan
2016-07-01
We explicitly compute the plasma wave (PW) induced by a plane gravitational wave (GW) traveling through a region of strongly magnetized plasma, governed by force-free electrodynamics. The PW comoves with the GW and absorbs its energy to grow over time, creating an essentially force-free counterpart to the inverse-Gertsenshtein effect. The time-averaged Poynting flux of the induced PW is comparable to the vacuum case, but the associated current may offer a more sensitive alternative to photodetection when designing experiments for detecting/constraining high-frequency gravitational waves. Aside from the exact solutions, we also offer an analysis of the general properties of the GW to PW conversion process, which should find use when evaluating electromagnetic counterparts to astrophysical gravitational waves that are generated directly by the latter as a second-order phenomenon.
High frequency fast wave current drive for DEMO
NASA Astrophysics Data System (ADS)
Koch, R.; Lerche, E.; Van Eester, D.; Nightingale, M.
2011-12-01
A steady-state tokamak reactor (SSTR) requires a high efficiency current drive system, from plug to driven mega-amps. RF systems working in the ion-cyclotron range of frequencies (ICRF) have high efficiency from plug to antenna but a limited current drive (CD) efficiency and centrally peaked CD profiles. The latter feature is not adequate for a SSTR where the current should be sufficiently broad to keep the central safety factor (possibly significantly) above 1. In addition, the fact that the fast wave (FW) is evanescent at the edge limits coupling, requiring high voltage operation, which makes the system dependent on plasma edge properties and prone to arcing, reducing its reliability. A possible way to overcome these weaknesses is to operate at higher frequency (10 times or more the cyclotron frequency). The advantages are: (1) The coupling can be much better (waves propagate in vacuum) if the parallel refractive index n∥ is kept below one, (2) The FW group velocity tends to align to the magnetic field, so the power circumnavigates the magnetic axis and can drive off-axis current, (3) Due to the latter property, n∥ can be upshifted along the wave propagation path, allowing low n∥ launch (hence good coupling, large CD efficiency) with ultimately good electron absorption (which requires higher n∥). Note however that the n∥ upshift is a self-organized feature, that electron absorption is in competition with α-particle absorption and that uncoupling of the FW from the lower hybrid resonance at the edge requires n∥ slightly above one. The latter possibly counterproductive features might complicate the picture. The different aspects of this potentially attractive off-axis FWCD scheme are discussed.
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.
Gravitational Waves in Effective Quantum Gravity
NASA Astrophysics Data System (ADS)
Calmet, Xavier; Kuntz, Iberê; Mohapatra, Sonali
2016-08-01
In this short paper we investigate quantum gravitational effects on Einstein's equations using Effective Field Theory techniques. We consider the leading order quantum gravitational correction to the wave equation. Besides the usual massless mode, we find a pair of modes with complex masses. These massive particles have a width and could thus lead to a damping of gravitational waves if excited in violent astrophysical processes producing gravitational waves such as e.g. black hole mergers. We discuss the consequences for gravitational wave events such as GW 150914 recently observed by the Advanced LIGO collaboration.
Norin, L; Leyser, T B; Nordblad, E; Thidé, B; McCarrick, M
2009-02-13
Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA. PMID:19257596
Norin, L.; Leyser, T. B.; Nordblad, E.; Thide, B.; McCarrick, M.
2009-02-13
Experimental results of secondary electromagnetic radiation, stimulated by high-frequency radio waves irradiating the ionosphere, are reported. We have observed emission peaks, shifted in frequency up to a few tens of Hertz from radio waves transmitted at several megahertz. These emission peaks are by far the strongest spectral features of secondary radiation that have been reported. The emissions are attributed to stimulated Brillouin scattering, long predicted but hitherto never unambiguously identified in high-frequency ionospheric interaction experiments. The experiments were performed at the High-Frequency Active Auroral Research Program (HAARP), Alaska, USA.
First test of high frequency Gravity Waves from inflation using Advanced LIGO
Lopez, Alejandro; Freese, Katherine E-mail: ktfreese@umich.edu
2015-01-01
Inflation models ending in a first order phase transition produce gravitational waves (GW) via bubble collisions of the true vacuum phase. We demonstrate that these bubble collisions can leave an observable signature in Advanced LIGO, an upcoming ground-based GW experiment. These GW are dependent on two parameters of the inflationary model: ε represents the energy difference between the false vacuum and the true vacuum of the inflaton potential, and χ measures how fast the phase transition ends (χ ∼ the number of e-folds during the actual phase transition). Advanced LIGO will be able to test the validity of single-phase transition models within the parameter space 10{sup 7} GeV∼< ε{sup 1/4} ∼< 10{sup 10} GeV and 0.19 ∼< χ ∼< 1. If inflation occurred through a first order phase transition, then Advanced LIGO could be the first to discover high frequency GW from inflation.
FAST TRACK COMMUNICATION: A gravitational wave window on extra dimensions
NASA Astrophysics Data System (ADS)
Clarkson, Chris; Seahra, Sanjeev S.
2007-05-01
We report on the possibility of detecting a submillimetre-sized extra dimension by observing gravitational waves (GWs) emitted by point-like objects orbiting a braneworld black hole. Matter in the 'visible' universe can generate a discrete spectrum of high frequency GWs with amplitudes moderately weaker than the predictions of general relativity, while GW signals generated by matter on a 'shadow' brane hidden in the bulk are potentially strong enough to be detected using current technology. We know of no other astrophysical phenomena that produce GWs with a similar spectrum, which stresses the need to develop detectors capable of measuring this high-frequency signature of large extra dimensions.
Self-adaptive method for high frequency multi-channel analysis of surface wave method
Technology Transfer Automated Retrieval System (TEKTRAN)
When the high frequency multi-channel analysis of surface waves (MASW) method is conducted to explore soil properties in the vadose zone, existing rules for selecting the near offset and spread lengths cannot satisfy the requirements of planar dominant Rayleigh waves for all frequencies of interest ...
Generation of Gravitational Waves with Nuclear Reactions
NASA Astrophysics Data System (ADS)
Fontana, Giorgio; Baker, Robert M. L.
2006-01-01
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 (~ 3.03×1024 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., 3.67×108 N) acting over extremely short time spans (e.g., 3.3×10-22 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 8.5×1010 W to 1.64×1025 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 ~ 0.005 are theoretically achieved in the laboratory, which might have interesting general-relativity and nuclear-physics consequences.
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.
NASA Technical Reports Server (NTRS)
Jensen, Eric J.
2016-01-01
Recent investigations of the influence of atmospheric waves on ice nucleation in cirrus have identified a number of key processes and sensitivities: (1) ice concentrations produced by homogeneous freezing are strongly dependent on cooling rates, with gravity waves dominating upper tropospheric cooling rates; (2) rapid cooling driven by high-frequency waves are likely responsible for the rare occurrences of very high ice concentrations in cirrus; (3) sedimentation and entrainment tend to decrease ice concentrations as cirrus age; and (4) in some situations, changes in temperature tendency driven by high-frequency waves can quench ice nucleation events and limit ice concentrations. Here we use parcel-model simulations of ice nucleation driven by long-duration, constant-pressure balloon temperature time series, along with an extensive dataset of cold cirrus microphysical properties from the recent ATTREX high-altitude aircraft campaign, to statistically examine the importance of high-frequency waves as well as the consistency between our theoretical understanding of ice nucleation and observed ice concentrations. The parcel-model simulations indicate common occurrence of peak ice concentrations exceeding several hundred per liter. Sedimentation and entrainment would reduce ice concentrations as clouds age, but 1-D simulations using a wave parameterization (which underestimates rapid cooling events) still produce ice concentrations higher than indicated by observations. We find that quenching of nucleation events by high-frequency waves occurs infrequently and does not prevent occurrences of large ice concentrations in parcel simulations of homogeneous freezing. In fact, the high-frequency variability in the balloon temperature data is entirely responsible for production of these high ice concentrations in the simulations.
C1IV:. Gravitational Wave Data Analysis
NASA Astrophysics Data System (ADS)
Sathyaprakash, B. S.
2002-09-01
Resonant bar detectors are routinely searching for astronomical sources of gravitational waves and to setting upper limits on event rates. Interferometric detectors are beginning to operate at sensitivity levels good enough to set meaningful upper limits and begin astrophysical searches. With the long baseline interferometers scheduled to take data at unprecedented sensitivity levels the next few years will be a very exciting period for gravitational waves. In session C1iv there were talks focusing on gravitational wave searches (Krolak and Sintes), setting upper limits on astrophysical signals (Brady and Whelan), theoretical developments in modelling binary black holes (Iyer), testing general relativity with gravitational wave data (Will) and tools for gravitational wave data analysis (Schutz). There was also a one-hour round-table discussion on setting upper limits chaired by Andersson.
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
NASA Astrophysics Data System (ADS)
Masserey, B.; Raemy, C.; Fromme, P.
2012-05-01
Aerospace structures contain multi-layer components subjected to cyclic loading conditions; fatigue cracks and disbonds can develop, often at fastener holes. High-frequency guided waves have the potential for non-destructive damage detection at critical and difficult to access locations from a stand-off distance. Using commercially available ultrasonic transducers, high frequency guided waves were generated that penetrate through the complete thickness of a model structure, consisting of two adhesively bonded aluminum plates. The wave propagation along the specimen was measured and quantified using a laser interferometer. The wave propagation and scattering at internal defects was simulated using Finite Element (FE) models and good agreement with the measurement results found. The detection sensitivity using standard pulse-echo measurements was verified and the influence of the stand-off distance predicted from the FE simulation results.
Gravitaton Wave and Gravitational-Photon Interaction
NASA Astrophysics Data System (ADS)
Khasanov, Kholmurad
2013-06-01
Gravitation waves and gravitational-photon interaction with high energy photons emission is found experimentally. Super-compressibility phenomenon was studied. Spectral investigations of supersonic jets and incandescent nichrome thread and wolfram spiral were studied. The shifting of the emission spectrum was detected depending on vector of gravity. The increasing frequency of light emitted against gravity vector is measured. Uneven along the spectrum character of intensity increasing is found. Generation of short-wavelength component of the spectrum is observed in case of more power of heating. The measurements show that presented interactions have resonance nature. Our experiments demonstrate the existence resonance nature. Our experiments demonstrate the gravitation wave and generation and existence of gravitational-photon interactions. From left to right: Fig. 1-2. Visualization of the gravitation wave. Fig. 3-5. Gravitational-photon interaction in HF field.
Masserey, Bernard; Raemy, Christian; Fromme, Paul
2014-09-01
Aerospace structures often contain multi-layered metallic components where hidden defects such as fatigue cracks and localized disbonds can develop, necessitating non-destructive testing. Employing standard wedge transducers, high frequency guided ultrasonic waves that penetrate through the complete thickness were generated in a model structure consisting of two adhesively bonded aluminium plates. Interference occurs between the wave modes during propagation along the structure, resulting in a frequency dependent variation of the energy through the thickness with distance. The wave propagation along the specimen was measured experimentally using a laser interferometer. Good agreement with theoretical predictions and two-dimensional finite element simulations was found. Significant propagation distance with a strong, non-dispersive main wave pulse was achieved. The interaction of the high frequency guided ultrasonic waves with small notches in the aluminium layer facing the sealant and on the bottom surface of the multilayer structure was investigated. Standard pulse-echo measurements were conducted to verify the detection sensitivity and the influence of the stand-off distance predicted from the finite element simulations. The results demonstrated the potential of high frequency guided waves for hidden defect detection at critical and difficult to access locations in aerospace structures from a stand-off distance. PMID:24856653
Optics in a nonlinear gravitational plane wave
NASA Astrophysics Data System (ADS)
Harte, Abraham I.
2015-09-01
Gravitational waves can act like gravitational lenses, affecting the observed positions, brightnesses, and redshifts of distant objects. Exact expressions for such effects are derived here in general relativity, allowing for arbitrarily-moving sources and observers in the presence of plane-symmetric gravitational waves. At least for freely falling sources and observers, it is shown that the commonly-used predictions of linear perturbation theory can be generically overshadowed by nonlinear effects; even for very weak gravitational waves, higher-order perturbative corrections involve secularly-growing terms which cannot necessarily be neglected when considering observations of sufficiently distant sources. Even on more moderate scales where linear effects remain at least marginally dominant, nonlinear corrections are qualitatively different from their linear counterparts. There is a sense in which they can, for example, mimic the existence of a third type of gravitational wave polarization.
Inversion of high frequency surface waves with fundamental and higher modes
Xia, J.; Miller, R.D.; Park, C.B.; Tian, G.
2003-01-01
The phase velocity of Rayleigh-waves of a layered earth model is a function of frequency and four groups of earth parameters: compressional (P)-wave velocity, shear (S)-wave velocity, density, and thickness of layers. For the fundamental mode of Rayleigh waves, analysis of the Jacobian matrix for high frequencies (2-40 Hz) provides a measure of dispersion curve sensitivity to earth model parameters. S-wave velocities are the dominant influence of the four earth model parameters. This thesis is true for higher modes of high frequency Rayleigh waves as well. Our numerical modeling by analysis of the Jacobian matrix supports at least two quite exciting higher mode properties. First, for fundamental and higher mode Rayleigh wave data with the same wavelength, higher modes can "see" deeper than the fundamental mode. Second, higher mode data can increase the resolution of the inverted S-wave velocities. Real world examples show that the inversion process can be stabilized and resolution of the S-wave velocity model can be improved when simultaneously inverting the fundamental and higher mode data. ?? 2002 Elsevier Science B.V. All rights reserved.
Gravitational waves and light cosmic strings
NASA Astrophysics Data System (ADS)
Depies, Matthew
Gravitational wave signatures from cosmic strings are analyzed numerically. Cosmic string networks form during phase transistions in the early universe and these networks of long cosmic strings break into loops that radiate energy in the form of gravitational waves until they decay. The gravitational waves come in the form of harmonic modes from individual string loops, a "confusion noise" from galactic loops, and a stochastic background of gravitational waves from a network of loops. In this study string loops of larger size a and lower string tensions G m, (where m the mass per unit length of the string) are investigated than in previous studies. Several detectors are currently searching for gravitational waves and a space based satellite, the Laser Interferometer Space Antenna (LISA), is in the final stages of pre-flight. The results for large loop sizes (a = 0.1) put an upper limit of about G m < 10 -9 and indicate that gravitational waves from string loops down to G m [approximate] 10 -20 could be detectabe by LISA. The string tension is related to the energy scale of the phase transition and the Planck mass via Gm = [Special characters omitted.] , so the limits on G m set the energy scale of any phase transition L s < 10^-4.5 m pl . Our results indicate that loops may form a significant gravitational wave signal, even for string tensions too low to have larger cosmological effects.
The Millikan shaking experiments and high-frequency seismic wave propagation in Southern California
NASA Astrophysics Data System (ADS)
Tanimoto, Toshiro; Okamoto, Taro
2014-08-01
In order to study high-frequency seismic wave propagation, seismic wavefields generated by resonant-shaking experiments of the Millikan Library, on the campus of California Institute Technology (Pasadena, California, USA), were analysed. Because the resonant shaking frequencies are 1.12 Hz (the east-west direction) and 1.64 Hz (the north-south direction), this active-source experiment can provide opportunities for studying high-frequency seismic wave propagation in Southern California. Because they are very narrow frequency band data, the analyses must be quite different from ordinary time-domain analyses. We show, theoretically, that the signals must be dominated by surface waves. Adopting this surface wave assumption, we proceed to make two separate analyses, one on spectral amplitude and the other on phase. We present a new method to derive group velocity from phase based on the cross correlations between the station in the Millikan Library (MIK) and stations in the regional network. Our results support that an active-source experiment by resonant shaking of a building is a feasible approach for high-frequency seismic wave studies.
Monitoring of corrosion damage using high-frequency guided ultrasonic waves
NASA Astrophysics Data System (ADS)
Chew, D.; Fromme, P.
2014-03-01
Due to adverse environmental conditions corrosion can develop during the life cycle of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the integrity and load bearing capacity of the structure. Structural health monitoring of corrosion damage in difficult to access areas can in principle be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, high frequency guided wave modes were generated that penetrate through the complete thickness of the structure. Wall thickness reduction was induced using accelerated corrosion in a salt water bath. The corrosion damage was monitored based on the effect on the wave propagation and interference of the different modes. The change in the wave interference was quantified based on an analysis in the frequency domain (Fourier transform) and was found to match well with theoretical predictions for the wall thickness loss. High frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.
Monitoring of corrosion damage using high-frequency guided ultrasonic waves
NASA Astrophysics Data System (ADS)
Chew, D.; Fromme, P.
2015-03-01
Due to adverse environmental conditions corrosion can develop during the life cycle of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the integrity and load bearing capacity of the structure. Structural health monitoring of corrosion damage in difficult to access areas can in principle be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, high frequency guided wave modes were generated that penetrate through the complete thickness of the structure. Wall thickness reduction was induced using accelerated corrosion in a salt water bath. The corrosion damage was monitored based on the effect on the wave propagation and interference of the different modes. The change in the wave interference was quantified based on an analysis in the frequency domain (Fourier transform) and was found to match well with theoretical predictions for the wall thickness loss. High frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.
Heating of ions by high frequency electromagnetic waves in magnetized plasmas
Zestanakis, P. A.; Kominis, Y.; Hizanidis, K.; Ram, A. K.
2013-07-15
The heating of ions by high frequency electrostatic waves in magnetically confined plasmas has been a paradigm for studying nonlinear wave-particle interactions. The frequency of the waves is assumed to be much higher than the ion cyclotron frequency and the waves are taken to propagate across the magnetic field. In fusion type plasmas, electrostatic waves, like the lower hybrid wave, cannot access the core of the plasma. That is a domain for high harmonic fast waves or electron cyclotron waves—these are primarily electromagnetic waves. Previous studies on heating of ions by two or more electrostatic waves are extended to two electromagnetic waves that propagate directly across the confining magnetic field. While the ratio of the frequency of each wave to the ion cyclotron frequency is large, the frequency difference is assumed to be near the ion cyclotron frequency. The nonlinear wave-particle interaction is studied analytically using a two time-scale canonical perturbation theory. The theory elucidates the effects of various parameters on the gain in energy by the ions—parameters such as the amplitudes and polarizations of the waves, the ratio of the wave frequencies to the cyclotron frequency, the difference in the frequency of the two waves, and the wave numbers associated with the waves. For example, the ratio of the phase velocity of the envelope formed by the two waves to the phase velocity of the carrier wave is important for energization of ions. For a positive ratio, the energy range is much larger than for a negative ratio. So waves like the lower hybrid waves will impart very little energy to ions. The theoretical results are found to be in good agreement with numerical simulations of the exact dynamical equations. The analytical results are used to construct mapping equations, simplifying the derivation of the motion of ions, which are, subsequently, used to follow the evolution of an ion distribution function. The heating of ions can then be
Reheating and primordial gravitational waves in generalized Galilean genesis
NASA Astrophysics Data System (ADS)
Nishi, Sakine; Kobayashi, Tsutomu
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 Ωgwpropto f3 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 Ωgw~ 10‑12 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.
Microwave background anisotropy induced by gravitational waves
NASA Technical Reports Server (NTRS)
Linder, Eric V.
1988-01-01
A cosmological background of gravitational waves induces redshift perturbations in light transversing it. Calculations of this Sachs-Wolfe effect on the microwave background are presented in an Omega = 1 Friedmann universe as a function of angular scale and gravitational wave spectrum. Blurriness of the last-scattering surface can cause nonnegligible dilution of the anisotropy for wavelengths less than about 100 Mpc. The limit implied for the energy density of the gravitational waves is given. A difficulty in associating a linear scale with an angular anisotropy, due to the clumpiness of the universe, is also pointed out.
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.
Estimation of pseudo-2D shear-velocity section by inversion of high frequency surface waves
Luo, Y.; Liu, J.; Xia, J.; Xu, Y.; Liu, Q.
2006-01-01
A scheme to generate pseudo-2D shear-velocity sections with high horizontal resolution and low field cost by inversion of high frequency surface waves is presented. It contains six steps. The key step is the joint method of crossed correlation and phase shift scanning. This joint method chooses only two traces to generate image of dispersion curve. For Rayleigh-wave dispersion is most important for estimation of near-surface shear-wave velocity, it can effectively obtain reliable images of dispersion curves with a couple of traces. The result of a synthetic example shows the feasibility of this scheme. ?? 2005 Society of Exploration Geophysicists.
NASA Technical Reports Server (NTRS)
Singh, Nagendra; Khazanov, George; Mukhter, Ali
2006-01-01
Satellite observations in the auroral plasma have revealed that extremely low frequency (ELF) waves play a dominant role in the acceleration of electrons and ions in the auroral plasma. The electromagnetic components of the ELF (EMELF) waves are the electromagnetic ion cyclotron (EMIC) waves below the cyclotron frequency of the lightest ion species in a multi-ion plasma. Shear Alfv6n waves (SAWS) constitute the lowest frequency components of the ELF waves below the ion cyclotron frequency of the heaviest ion. The -2 mechanism for the transfer of energy from such EMELF waves to ions affecting transverse ion heating still remains a matter of debate. A very ubiquitous fe8ture of ELF waves now observed in several rocket and satellite experiments is that they occur in conjunction with high-frequency electrostatic waves. The frequency spectrum of the composite wave turbulence extends from the low frequency of the Alfvenic waves to the high frequency of proton plasma frequency and/or the lower hybrid frequency. The spectrum does not show any feature organized by the ion cyclotron frequencies and their harmonics. Such broadband waves consisting of both the EM and ES waves are now popularly referred as BBELF waves. We present results here from 2.5-D particle-in-cell simulations showing that the ES components are directly generated by cross- field plasma instabilities driven by the drifts of the ions and electrons in the EM component of the BBELF waves.
High-frequency gravity waves and homogeneous ice nucleation in tropical tropopause layer cirrus
NASA Astrophysics Data System (ADS)
Jensen, Eric J.; Ueyama, Rei; Pfister, Leonhard; Bui, Theopaul V.; Alexander, M. Joan; Podglajen, Aurélien; Hertzog, Albert; Woods, Sarah; Lawson, R. Paul; Kim, Ji-Eun; Schoeberl, Mark R.
2016-06-01
The impact of high-frequency gravity waves on homogeneous-freezing ice nucleation in cold cirrus clouds is examined using parcel model simulations driven by superpressure balloon measurements of temperature variability experienced by air parcels in the tropical tropopause region. We find that the primary influence of high-frequency waves is to generate rapid cooling events that drive production of numerous ice crystals. Quenching of ice nucleation events by temperature tendency reversal in the highest-frequency waves does occasionally produce low ice concentrations, but the overall impact of high-frequency waves is to increase the occurrence of high ice concentrations. The simulated ice concentrations are considerably higher than indicated by in situ measurements of cirrus in the tropical tropopause region. One-dimensional simulations suggest that although sedimentation reduces mean ice concentrations, a discrepancy of about a factor of 3 with observed ice concentrations remains. Reconciliation of numerical simulations with the observed ice concentrations will require inclusion of physical processes such as heterogeneous nucleation and entrainment.
ON THE FLARE INDUCED HIGH-FREQUENCY GLOBAL WAVES IN THE SUN
Kumar, Brajesh; Venkatakrishnan, P.; Mathur, Savita; GarcIa, R. A. E-mail: pvk@prl.res.in E-mail: rafael.garcia@cea.fr
2010-03-01
Recently, Karoff and Kjeldsen presented evidence of strong correlation between the energy in the high-frequency part (5.3 < {nu} < 8.3 mHz) of the acoustic spectrum of the Sun and the solar X-ray flux. They have used disk-integrated intensity observations of the Sun obtained from the Variability of solar IRradiance and Gravity Oscillations instrument on board Solar and Heliospheric Observatory (SOHO) spacecraft. Similar signature of flares in velocity observations has not been confirmed till now. The study of low-degree high-frequency waves in the Sun is important for our understanding of the dynamics of the deeper solar layers. In this Letter, we present the analysis of the velocity observations of the Sun obtained from the Michelson and Doppler Imager (MDI) and the Global Oscillations at Low Frequencies (GOLF) instruments on board SOHO for some major flare events of the solar cycle 23. Application of wavelet techniques to the time series of disk-integrated velocity signals from the solar surface using the full-disk Dopplergrams obtained from the MDI clearly indicates that there is enhancement of high-frequency global waves in the Sun during the flares. This signature of flares is also visible in the Fourier Power Spectrum of these velocity oscillations. On the other hand, the analysis of disk-integrated velocity observations obtained from the GOLF shows only marginal evidence of effects of flares on high-frequency oscillations.
On the Flare Induced High-Frequency Global Waves in the Sun
NASA Astrophysics Data System (ADS)
Kumar, Brajesh; Mathur, Savita; García, R. A.; Venkatakrishnan, P.
2010-03-01
Recently, Karoff & Kjeldsen presented evidence of strong correlation between the energy in the high-frequency part (5.3 < ν < 8.3 mHz) of the acoustic spectrum of the Sun and the solar X-ray flux. They have used disk-integrated intensity observations of the Sun obtained from the Variability of solar IRradiance and Gravity Oscillations instrument on board Solar and Heliospheric Observatory (SOHO) spacecraft. Similar signature of flares in velocity observations has not been confirmed till now. The study of low-degree high-frequency waves in the Sun is important for our understanding of the dynamics of the deeper solar layers. In this Letter, we present the analysis of the velocity observations of the Sun obtained from the Michelson and Doppler Imager (MDI) and the Global Oscillations at Low Frequencies (GOLF) instruments on board SOHO for some major flare events of the solar cycle 23. Application of wavelet techniques to the time series of disk-integrated velocity signals from the solar surface using the full-disk Dopplergrams obtained from the MDI clearly indicates that there is enhancement of high-frequency global waves in the Sun during the flares. This signature of flares is also visible in the Fourier Power Spectrum of these velocity oscillations. On the other hand, the analysis of disk-integrated velocity observations obtained from the GOLF shows only marginal evidence of effects of flares on high-frequency oscillations.
Gravitational wave astronomy: the current status
NASA Astrophysics Data System (ADS)
Blair, David; Ju, Li; Zhao, ChunNong; Wen, LinQing; Chu, Qi; Fang, Qi; Cai, RongGen; Gao, JiangRui; Lin, XueChun; Liu, Dong; Wu, Ling-An; Zhu, ZongHong; Reitze, David H.; Arai, Koji; Zhang, Fan; Flaminio, Raffaele; Zhu, XingJiang; Hobbs, George; Manchester, Richard N.; Shannon, Ryan M.; Baccigalupi, Carlo; Gao, Wei; Xu, Peng; Bian, Xing; Cao, ZhouJian; Chang, ZiJing; Dong, Peng; Gong, XueFei; Huang, ShuangLin; Ju, Peng; Luo, ZiRen; Qiang, Li'E.; Tang, WenLin; Wan, XiaoYun; Wang, Yue; Xu, ShengNian; Zang, YunLong; Zhang, HaiPeng; Lau, Yun-Kau; Ni, Wei-Tou
2015-12-01
In the centenary year of Einstein's General Theory of Relativity, this paper reviews the current status of gravitational wave astronomy across a spectrum which stretches from attohertz to kilohertz frequencies. Sect. 1 of this paper reviews the historical development of gravitational wave astronomy from Einstein's first prediction to our current understanding the spectrum. It is shown that detection of signals in the audio frequency spectrum can be expected very soon, and that a north-south pair of next generation detectors would provide large scientific benefits. Sect. 2 reviews the theory of gravitational waves and the principles of detection using laser interferometry. The state of the art Advanced LIGO detectors are then described. These detectors have a high chance of detecting the first events in the near future. Sect. 3 reviews the KAGRA detector currently under development in Japan, which will be the first laser interferometer detector to use cryogenic test masses. Sect. 4 of this paper reviews gravitational wave detection in the nanohertz frequency band using the technique of pulsar timing. Sect. 5 reviews the status of gravitational wave detection in the attohertz frequency band, detectable in the polarisation of the cosmic microwave background, and discusses the prospects for detection of primordial waves from the big bang. The techniques described in sects. 1-5 have already placed significant limits on the strength of gravitational wave sources. Sects. 6 and 7 review ambitious plans for future space based gravitational wave detectors in the millihertz frequency band. Sect. 6 presents a roadmap for development of space based gravitational wave detectors by China while sect. 7 discusses a key enabling technology for space interferometry known as time delay interferometry.
On the estimation of gravitational wave spectrum from cosmic domain walls
Hiramatsu, Takashi; Kawasaki, Masahiro; Saikawa, Ken'ichi E-mail: kawasaki@icrr.u-tokyo.ac.jp
2014-02-01
We revisit the production of gravitational waves from unstable domain walls analyzing their spectrum by the use of field theoretic lattice simulations with grid size 1024{sup 3}, which is larger than the previous study. We have recognized that there exists an error in the code used in the previous study, and the correction of the error leads to the suppression of the spectrum of gravitational waves at high frequencies. The peak of the spectrum is located at the scale corresponding to the Hubble radius at the time of the decay of domain walls, and its amplitude is consistent with the naive estimation based on the quadrupole formula. Using the numerical results, the magnitude and the peak frequency of gravitational waves at the present time are estimated. It is shown that for some choices of parameters the signal of gravitational waves is strong enough to be probed in the future gravitational wave experiments.
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.
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.
Gravitational Wave Physics with Binary Love Relations
NASA Astrophysics Data System (ADS)
Yagi, Kent; Yunes, Nicolas
2016-03-01
Gravitational waves from the late inspiral of neutron star binaries encode rich information about their internal structure at supranuclear densities through their tidal deformabilities. However, extracting the individual tidal deformabilities of the components of a binary is challenging with future ground-based gravitational wave interferometers due to degeneracies between them. We overcome this difficulty by finding new, approximate universal relations between the individual tidal deformabilities that depend on the mass ratio of the two stars and are insensitive to their internal structure. Such relations have applications not only to gravitational wave astrophysics, but also to nuclear physics as they improve the measurement accuracy of tidal parameters. Moreover, the relations improve our ability to test extreme gravity and perform cosmology with gravitational waves emitted from neutron star binaries.
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.
High-frequency programmable acoustic wave device realized through ferroelectric domain engineering
Ivry, Yachin E-mail: cd229@eng.cam.ac.uk; Wang, Nan; Durkan, Colm E-mail: cd229@eng.cam.ac.uk
2014-03-31
Surface acoustic wave devices are extensively used in contemporary wireless communication devices. We used atomic force microscopy to form periodic macroscopic ferroelectric domains in sol-gel deposited lead zirconate titanate, where each ferroelectric domain is composed of many crystallites, each of which contains many microscopic ferroelastic domains. We examined the electro-acoustic characteristics of the apparatus and found a resonator behavior similar to that of an equivalent surface or bulk acoustic wave device. We show that the operational frequency of the device can be tailored by altering the periodicity of the engineered domains and demonstrate high-frequency filter behavior (>8 GHz), allowing low-cost programmable high-frequency resonators.
Gravitational wave detection in the laboratory.
NASA Astrophysics Data System (ADS)
Chen, Y. T.; Kawashima, N.; Othman, M.; Chia, S. P.; Karim, M.; Sanugi, B.; Lim, B. H.; Chong, K. K.
1998-09-01
After reviewing the research work of gravitational wave detection in the laboratory, particularly long base laser interferometer detectors, the authors report on the recent progress of gravitational wave detection using laser interferometer (Tianyin-100) in Malaysia. The authors also outline the brief plan for Tianyin-500 in the future as a full-scale observatory competitive to other projects such as Ligo, Geo600, etc.
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).
Liu, Yong-Xin; Gao, Fei; Liu, Jia; Wang, You-Nian
2014-07-28
Radial uniformity measurements of plasma density were carried out by using a floating double probe in a cylindrical (21 cm in electrode diameter) capacitive discharge reactor driven over a wide range of frequencies (27–220 MHz). At low rf power, a multiple-node structure of standing wave effect was observed at 130 MHz. The secondary density peak caused by the standing wave effect became pronounced and shifts toward the axis as the driving frequency further to increase, indicative of a much more shortened standing-wave wavelength. With increasing rf power, the secondary density peak shift toward the radial edge, namely, the standing-wave wavelength was increased, in good qualitative agreement with the previous theory and simulation results. At higher pressures and high frequencies, the rf power was primarily deposited at the periphery of the electrode, due to the fact that the waves were strongly damped as they propagated from the discharge edge into the center.
Gravitational wave asteroseismology with protoneutron stars
NASA Astrophysics Data System (ADS)
Sotani, Hajime; Takiwaki, Tomoya
2016-08-01
We examine the time evolution of the frequencies of the gravitational wave after the bounce within the framework of relativistic linear perturbation theory using the results of one-dimensional numerical simulations of core-collapse supernovae. Protoneutron star models are constructed in such a way that the mass and the radius of the protoneutron star become equivalent to the results obtained from the numerical simulations. Then we find that the frequencies of gravitational waves radiating from protoneutron stars strongly depend on the mass and the radius of protoneutron stars, but almost independently of the profiles of the electron fraction and the entropy per baryon inside the star. Additionally, we find that the frequencies of gravitational waves can be characterized by the square root of the average density of the protoneutron star irrespective of the progenitor models, which are completely different from the empirical formula for cold neutron stars. The dependence of the spectra on the mass and the radius is different from that of the g -mode: the oscillations around the surface of protoneutron stars due to the convection and the standing accretion-shock instability. Careful observation of these modes of gravitational waves can determine the evolution of the mass and the radius of protoneutron stars after core bounce. Furthermore, the expected frequencies of gravitational waves are around a few hundred hertz in the early stages after bounce, which must be a good candidate for the ground-based gravitational wave detectors.
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.
Ocean wave parameters and spectrum estimated from single and dual high-frequency radar systems
NASA Astrophysics Data System (ADS)
Hisaki, Yukiharu
2016-09-01
The high-frequency (HF) radar inversion algorithm for spectrum estimation (HIAS) can estimate ocean wave directional spectra from both dual and single radar. Wave data from a dual radar and two single radars are compared with in situ observations. The agreement of the wave parameters estimated from the dual radar with those from in situ observations is the best of the three. In contrast, the agreement of the wave parameters estimated from the single radar in which no Doppler spectra are observed in the cell closest to the in situ observation point is the worst among the three. Wave data from the dual radar and the two single radars are compared. The comparison of the wave heights estimated from the single and dual radars shows that the area sampled by the Doppler spectra for the single radar is more critical than the number of Doppler spectra in terms of agreement with the dual-radar-estimated wave heights. In contrast, the comparison of the wave periods demonstrates that the number of Doppler spectra observed by the single radar is more critical for agreement of the wave periods than the area of the Doppler spectra. There is a bias directed to the radar position in the single radar estimated wave direction.
Relations among low ionosphere parameters and high frequency radio wave absorption
NASA Technical Reports Server (NTRS)
Cipriano, J. P.
1973-01-01
Charged particle conductivities measured in the very low ionosphere at White Sands Missile Range, New Mexico, and Wallops Island, Virginia, are compared with atmospheric parameters and high frequency radio wave absorption measurements. Charged particle densities are derived from the conductivity data. Between 33 and 58 km, positive conductivity correlated well with neutral atmospheric temperature, with temperature coefficients as large as 4.6%/deg K. Good correlations were also found between HF radio wave absorption and negative conductivity at altitudes as low as 53 km, indicating that the day-to-day absorption variations were principally due to variations in electron loss rate.
Gravitational wave astrophysics with compact binary systems
NASA Astrophysics Data System (ADS)
Addison, Eric
2014-10-01
Gravitational waves are ripples in the fabric of spacetime that convey information about changing gravitational fields. Large-scale detection projects are currently in operation, and more advanced detectors are being designed and built. Though we have yet to make a direct detection of a gravitational wave signal, upgrades to current detectors are expected to bring the first detections within the next year or two. Gravitational waves will bring us information about astrophysical phenomena that is complementary to the information gained from photon-based observations (e.g., telescopes and radio receivers). One of the primary sources of gravitational waves are binary systems: two massive objects that orbit around each other due to their mutual gravitational attraction. These systems can have very predictable gravitational wave signatures due to their repetitive motions, making them ideal gravitational wave sources. In this dissertation, I present two research projects pertaining to gravitational wave astrophysics and compact binary systems. In the first, I explore interactions between compact binary systems near the center of our galaxy with the supermassive black hole that resides there. I am interested in the final state of the binary as a result of the interaction, ranging from small perturbations to the orbit up to total disruption. In the case of disruption, I characterize the new orbits formed between the binary components and the central black hole, known as extreme mass ratio inspirals. For binaries that survive the encounter, I examine the changes they experience, and find on average, they will merge together as a result of gravitational wave emission faster than before the encounter. In the second project, I propose a new method of measuring the radius of the swirling disc of gas and dust that encircles some stars in compact binary systems, known as the accretion disc. This method relies on the use of coupled electromagnetic and gravitational wave
The possible role of high-frequency waves in heating solar coronal loops
NASA Technical Reports Server (NTRS)
Porter, Lisa J.; Klimchuk, James A.; Sturrock, Peter A.
1994-01-01
We investigate the role of high-frequency waves in the heating of solar active region coronal loops. We assume a uniform background magnetic field, and we introduce a density stratification in a direction perpendicular to this field. We focus on ion compressive viscosity as the damping mechanism of the waves. We incorporate viscosity self-consistently into the equations, and we derive a dispersion relation by adopting a slab model, where the density inside the slab is greater than that outside. Such a configuration supports two types of modes: surface waves and trapped body waves. In order to determine under what conditions these waves may contribute to the heating of active regions, we solve our dispersion relation for a range of densities, temperatures, magnetic field strengths, density ratios, wavevector magnitudes, wavevector ratios, and slab widths. We find that surface waves exhibit very small damping, but body waves can potentially damp at rates needed to balance radiative losses. However, the required frequencies of these body waves are very high. For example, the wave frequency must be at least 5.0/s for a slab density of 10(exp 9,5)/cc, a slab temperature of 10(exp 6,5) K, a field strength of 100 G, and a density ratio of 5. For a slab density of 10(exp 10)/cc, this frequency increases to 8.8/s. Although these frequencies are very high, there in no observational evidence to rule out their existence, and they may be generated both below the corona and at magnetic reconnection sites in the corona. However, we do find that, for slab densities of 10(exp 10)/cc or less, the dissipation of high-frequency waves will be insufficient to balance the radiative losses if the magnetic field strength exceeds roughly 200 G. Because the magnetic field is known to exceed 200 G in many active region loops, particularly low-lying loops and loops emanating from sunspots, it is unlikely that high-frequency waves can provide sufficient heating in these regions.
Strong gravitational lensing of gravitational waves in Einstein Telescope
Piórkowska, Aleksandra; Biesiada, Marek; Zhu, Zong-Hong E-mail: marek.biesiada@us.edu.pl
2013-10-01
Gravitational wave experiments have entered a new stage which gets us closer to the opening a new observational window on the Universe. In particular, the Einstein Telescope (ET) is designed to have a fantastic sensitivity that will provide with tens or hundreds of thousand NS-NS inspiral events per year up to the redshift z = 2. Some of such events should be gravitationally lensed by intervening galaxies. We explore the prospects of observing gravitationally lensed inspiral NS-NS events in the Einstein telescope. Being conservative we consider the lens population of elliptical galaxies. It turns out that depending on the local insipral rate ET should detect from one per decade detection in the pessimistic case to a tens of detections per year for the most optimistic case. The detection of gravitationally lensed source in gravitational wave detectors would be an invaluable source of information concerning cosmography, complementary to standard ones (like supernovae or BAO) independent of the local cosmic distance ladder calibrations.
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.
Gravitational Waves from a Dark Phase Transition.
Schwaller, Pedro
2015-10-30
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 n_{f} 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. PMID:26565451
Dissipation of modified entropic gravitational energy through gravitational waves
NASA Astrophysics Data System (ADS)
de Matos, Clovis Jacinto
2012-01-01
The phenomenological nature of a new gravitational type interaction between two different bodies derived from Verlinde's entropic approach to gravitation in combination with Sorkin's definition of Universe's quantum information content, is investigated. Assuming that the energy stored in this entropic gravitational field is dissipated under the form of gravitational waves and that the Heisenberg principle holds for this system, one calculates a possible value for an absolute minimum time scale in nature tau=15/16 Λ^{1/2}hbar G/c4˜9.27×10^{-105} seconds, which is much smaller than the Planck time t P =( ħG/ c 5)1/2˜5.38×10-44 seconds. This appears together with an absolute possible maximum value for Newtonian gravitational forces generated by matter Fg=32/30c7/Λ hbar G2˜ 3.84× 10^{165} Newtons, which is much higher than the gravitational field between two Planck masses separated by the Planck length F gP = c 4/ G˜1.21×1044 Newtons.
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.
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.
Nonlinear propagation of high-frequency energy from blast waves as it pertains to bat hearing
NASA Astrophysics Data System (ADS)
Loubeau, Alexandra
Close exposure to blast noise from military weapons training can adversely affect the hearing of both humans and wildlife. One concern is the effect of high-frequency noise from Army weapons training on the hearing of endangered bats. Blast wave propagation measurements were conducted to investigate nonlinear effects on the development of blast waveforms as they propagate from the source. Measurements were made at ranges of 25, 50, and 100 m from the blast. Particular emphasis was placed on observation of rise time variation with distance. Resolving the fine shock structure of blast waves requires robust transducers with high-frequency capability beyond 100 kHz, hence the limitations of traditional microphones and the effect of microphone orientation were investigated. Measurements were made with a wide-bandwidth capacitor microphone for comparison with conventional 3.175-mm (⅛-in.) microphones with and without baffles. The 3.175-mm microphone oriented at 90° to the propagation direction did not have sufficient high-frequency response to capture the actual rise times at a range of 50 m. Microphone baffles eliminate diffraction artifacts on the rise portion of the measured waveform and therefore allow for a more accurate measurement of the blast rise time. The wide-band microphone has an extended high-frequency response and can resolve shorter rise times than conventional microphones. For a source of 0.57 kg (1.25 lb) of C-4 plastic explosive, it was observed that nonlinear effects steepened the waveform, thereby decreasing the shock rise time, from 25 to 50 m. At 100m, the rise times had increased slightly. For comparison to the measured blast waveforms, several models of nonlinear propagation are applied to the problem of finite-amplitude blast wave propagation. Shock front models, such as the Johnson and Hammerton model, and full-waveform marching algorithms, such as the Anderson model, are investigated and compared to experimental results. The models
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.
High-frequency electromagnetic surface waves in a semi-bounded weakly ionized plasma
Moaied, M.; Tyshetskiy, Yu.; Vladimirov, S. V.
2013-02-15
High-frequency electromagnetic surface waves (SWs) in a weakly ionized plasma half-space with Maxwellian electrons are studied taking into account elastic electron-neutral collisions. The SWs spectrum and damping rate are obtained numerically for a wide range of wavelengths, and the asymptotes of damping rate are analytically calculated in some limits. It is shown that the high-frequency SWs become strongly damped at wavelengths {lambda}<{lambda}{sub Min}, where {lambda}{sub Min} significantly depends on plasma parameters (e.g., electron temperature and electron and neutral atom density). The relative importance of collisional and Cherenkov (collisionless) damping of SWs is investigated and is graphically shown for a range of plasma parameters and SW wavelengths. The behavior of weakly ionized plasma with respect to the SW propagation has been recovered for the collisional parameter {eta}.
Low Frequency Turbulence as the Source of High Frequency Waves in Multi-Component Space Plasmas
NASA Technical Reports Server (NTRS)
Khazanov, George V.; Krivorutsky, Emmanuel N.; Uritsky, Vadim M.
2011-01-01
Space plasmas support a wide variety of waves, and wave-particle interactions as well as wavewave interactions are of crucial importance to magnetospheric and ionospheric plasma behavior. High frequency wave turbulence generation by the low frequency (LF) turbulence is restricted by two interconnected requirements: the turbulence should be strong enough and/or the coherent wave trains should have the appropriate length. These requirements are strongly relaxed in the multi-component plasmas, due to the heavy ions large drift velocity in the field of LF wave. The excitation of lower hybrid waves (LHWs), in particular, is a widely discussed mechanism of interaction between plasma species in space and is one of the unresolved questions of magnetospheric multi-ion plasmas. It is demonstrated that large-amplitude Alfven waves, in particular those associated with LF turbulence, may generate LHW s in the auroral zone and ring current region and in some cases (particularly in the inner magnetosphere) this serves as the Alfven wave saturation mechanism. We also argue that the described scenario can playa vital role in various parts of the outer magnetosphere featuring strong LF turbulence accompanied by LHW activity. Using the data from THEMIS spacecraft, we validate the conditions for such cross-scale coupling in the near-Earth "flow-braking" magnetotail region during the passage of sharp injection/dipolarization fronts, as well as in the turbulent outflow region of the midtail reconnection site.
Joint inversion of high-frequency surface waves with fundamental and higher modes
Luo, Y.; Xia, J.; Liu, J.; Liu, Q.; Xu, S.
2007-01-01
Joint inversion of multimode surface waves for estimating the shear (S)-wave velocity has received much attention in recent years. In this paper, we first analyze sensitivity of phase velocities of multimodes of surface waves for a six-layer earth model, and then we invert surface-wave dispersion curves of the theoretical model and a real-world example. Sensitivity analysis shows that fundamental mode data are more sensitive to the S-wave velocities of shallow layers and are concentrated on a very narrow frequency band, while higher mode data are more sensitive to the parameters of relatively deeper layers and are distributed over a wider frequency band. These properties provide a foundation of using a multimode joint inversion to define S-wave velocities. Inversion results of both synthetic data and a real-world example demonstrate that joint inversion with the damped least-square method and the singular-value decomposition technique to invert high-frequency surface waves with fundamental and higher mode data simultaneously can effectively reduce the ambiguity and improve the accuracy of S-wave velocities. ?? 2007.
A Brief History of Gravitational Waves
NASA Astrophysics Data System (ADS)
Cervantes-Cota, Jorge; Galindo-Uribarri, Salvador; Smoot, George
2016-09-01
This review describes the discovery of gravitational waves. We recount the journey of predicting and finding those waves, since its beginning in the early twentieth century, their prediction by Einstein in 1916, theoretical and experimental blunders, efforts towards their detection, and finally the subsequent successful discovery.
Comment on ``Atomic gravitational wave interferometric sensor''
NASA Astrophysics Data System (ADS)
Bender, Peter L.
2011-07-01
The use of laser interferometers for detecting and studying gravitational-wave signals from many types of astronomical sources is being pursued actively by a number of groups in different countries. However, it has been suggested recently that cooled atom clouds in atom interferometers could be used to replace the test masses in space-based gravitational-wave detectors and the end mirrors in ground-based detectors [S. Dimopoulos, P. W. Graham, J. M. Hogan, M. A. Kasevich, and S. Rajendran, Phys. Rev. DPRVDAQ1550-7998 78, 122002 (2008).10.1103/PhysRevD.78.122002]. Some new error sources that apparently have not been included in proposals of atom interferometer gravitational-wave detectors will be discussed in this comment. They are based on additional effects of aberrations in the laser wave fronts that interact with the atom clouds.
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 waves in fourth order gravity
NASA Astrophysics Data System (ADS)
Capozziello, S.; Stabile, A.
2015-08-01
In the post-Minkowskian limit approximation, we study gravitational wave solutions for general fourth-order theories of gravity. Specifically, we consider a Lagrangian with a generic function of curvature invariants . It is well known that when dealing with General Relativity such an approach provides massless spin-two waves as propagating degree of freedom of the gravitational field while this theory implies other additional propagating modes in the gravity spectra. We show that, in general, fourth order gravity, besides the standard massless graviton is characterized by two further massive modes with a finite-distance interaction. We find out the most general gravitational wave solutions in terms of Green functions in vacuum and in presence of matter sources. If an electromagnetic source is chosen, only the modes induced by are present, otherwise, for any gravity model, we have the complete analogy with tensor modes of General Relativity. Polarizations and helicity states are classified in the hypothesis of plane wave.
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.
External control of ion waves in a plasma by high frequency fields
Kaw, P.K.; Dawson, J.M.
1973-12-18
An apparatus and method are described for stabilizing plasma instabilities, in a magnetically confined plasma column by transmitting into the plasma high frequency electromagnetic waves at a frequency close to the electron plasma frequency. The said frequencies, e.g., are between the plasma frequency and 1.5 times the plasma frequency at a power level below the level for producing parametric instabilities in a plasma having temperatures from below 10 eV to about 10 keV or more, at densities from below 10/sup 13/ to above 10/sup 18/ particles/cm/sup 3/. (Official Gazette)
Validation of HFCS-I on Calculation of High-Frequency Parameters of Helical Slow-Wave Structures
NASA Astrophysics Data System (ADS)
Zhu, Xiaofang; Yang, Zhonghai; Li, Bin; Li, Jianqing; Xu, Li
2010-02-01
To validate HFCS-I, a newly developed design tool for high frequency circuits of microwave tubes, the high-frequency parameters (including dispersion, interaction impedance and attenuation constant) of a typical helical slow-wave structure (SWS) for millimetre wave travelling-wave tube are calculated by HFCS-I and MAFIA. Both the direct calculation method and the Non-Resonant Perturbation (NRP) technique are adopted to get the interaction impedance. The obtained high-frequency parameters from HFCS-I and MAFIA are compared in detail and the consistency has proved the reliability and validity of HFCS-I.
Precision calculations of the gravitational wave background spectrum from inflation
Kuroyanagi, Sachiko; Chiba, Takeshi; Sugiyama, Naoshi
2009-05-15
The spectrum of the gravitational wave background originating from quantum fluctuations during inflation is calculated numerically for various inflation models over a wide range of frequencies. We take into account four ingredients: the scalar field dynamics during inflation making no use of the slow-roll approximation, the fermionic decay of the scalar field with a small coupling constant during the reheating process, the change of the effective number of degrees of freedom g{sub *} in the radiation-dominated era, and the anisotropic stress of free-streaming neutrinos. By numerically solving the evolution of gravitational waves during and after inflation up to the present, all of these effects can be examined comprehensively and accurately over a broad spectrum, even at very high frequencies. We find that the spectrum shows (i) a large deviation from the spectrum less accurate obtained by Taylor expanding around the CMB scale using the slow-roll approximation, (ii) a characteristic frequency dependence due to the reheating effect, and (iii) damping due to the g{sub *} changes and the neutrino anisotropic stress. We suggest that future analysis of the gravitational wave background should take into consideration the fact that analytical estimates using the Taylor expansion overestimate the amplitude of the spectrum.
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 wave background from Standard Model physics: qualitative features
NASA Astrophysics Data System (ADS)
Ghiglieri, J.; Laine, M.
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 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.
NASA Astrophysics Data System (ADS)
PanneerChelvam, Premkumar; Raja, Laxminarayan L.; Upadhyay, Rochan R.
2016-09-01
We discuss the computational modeling of a single microplasma and its interaction with high frequency electromagnetic waves in a microwave regime. The work is motivated by a strong recent interest in the area of reconfigurable plasma-based metamaterials (MM) and photonic crystals (PC) where the interaction of electromagnetic waves with plasma elements (e.g. microdischarges) forms the basis for the MM/PC operation. In this work the microplasma is assumed to be driven by a 1 GHz microwave source in a parallel plate electrode configuration. Its structure and properties are described using a fluid plasma model. The interaction of the microplasma with a 100 GHz transverse magnetic (TM) and transverse electric (TE) polarized microwave propagating in a rectangular waveguide is studied. Two operational regimes of the plasma discharge are considered. One in which the peak electron density is less than the critical density (under-dense) for the interacting wave and the other in which it is higher (over-dense). The under-dense plasma with positive less than unity dielectric constant has sufficient dielectric contrast from the surrounding medium that a slight perturbation of the incident wave and bending of wave path lines through the discharge is realized. The over-dense plasma interacts strongly with the TM polarized wave because of epsilon-zero resonance at the critical density locations and the wave path lines are observed to reverse their direction near the regions of critical plasma density. The transverse electric (TE) polarized wave does not exhibit epsilon-zero resonance and the interactions are weaker than the TM wave.
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.
NASA Astrophysics Data System (ADS)
Caplinger, J.; Sotnikov, V. I.; Wallerstein, A. J.
2014-12-01
A three dimensional numerical ray-tracing algorithm based on a Hamilton-Jacobi geometric optics approximation is used to analyze propagation of high frequency (HF) electromagnetic waves through a plasma with randomly distributed vortex structures having a spatial dependence in the plane perpendicular to earth's magnetic field. This spatial dependence in density is elongated and uniform along the magnetic field lines. Similar vortex structures may appear in the equatorial spread F region and in the Auroral zone of the ionosphere. The diffusion coefficient associated with wave vector deflection from a propagation path can be approximated by measuring the average deflection angle of the beam of rays. Then, the beam broadening can be described statistically using the Fokker-Planck equation. Visualizations of the ray propagation through generated density structures along with estimated and analytically calculated diffusion coefficients will be presented.
Photonic generation of high frequency millimeter-wave and transmission over optical fiber.
Kumar, Amitesh; Priye, Vishnu
2016-08-01
A novel technique of photonic generation of millimeter-waves beyond the presently reported 120 GHz and with a wider tunability (∼240 GHz) is proposed and demonstrated through a simulation experiment. The scheme consists of generating 24 times the frequency of a conventional low frequency microwave source using a combination of a LiNbO_{3} Mach-Zehnder modulator and four-wave mixing in a semiconductor optical amplifier. The filtering of a high frequency sideband and the suppression of a carrier are achieved by incorporating an optical band pass and fiber Bragg grating filters, respectively. Next, the spectral purity of the generated millimeter-wave parameters is evaluated after propagation through a conventional fiber of different lengths by digitally modulating it at 2.5 Gbps and generating an eye diagram. The constraints on the selection of the frequency of the millimeter-wave and length of fiber are discussed. The present method of millimeter-wave generation and distribution will find applications in photonic up/down conversion, phase-array antennas, photonic sensors, radars, and terahertz applications.
Photonic generation of high frequency millimeter-wave and transmission over optical fiber.
Kumar, Amitesh; Priye, Vishnu
2016-08-01
A novel technique of photonic generation of millimeter-waves beyond the presently reported 120 GHz and with a wider tunability (∼240 GHz) is proposed and demonstrated through a simulation experiment. The scheme consists of generating 24 times the frequency of a conventional low frequency microwave source using a combination of a LiNbO_{3} Mach-Zehnder modulator and four-wave mixing in a semiconductor optical amplifier. The filtering of a high frequency sideband and the suppression of a carrier are achieved by incorporating an optical band pass and fiber Bragg grating filters, respectively. Next, the spectral purity of the generated millimeter-wave parameters is evaluated after propagation through a conventional fiber of different lengths by digitally modulating it at 2.5 Gbps and generating an eye diagram. The constraints on the selection of the frequency of the millimeter-wave and length of fiber are discussed. The present method of millimeter-wave generation and distribution will find applications in photonic up/down conversion, phase-array antennas, photonic sensors, radars, and terahertz applications. PMID:27505360
Gravitational wave detection using atom interferometry
NASA Astrophysics Data System (ADS)
Hogan, Jason
2016-05-01
The advent of gravitational wave astronomy promises to provide a new window into the universe. Low frequency gravitational waves below 10 Hz are expected to offer rich science opportunities both in astrophysics and cosmology, complementary to signals in LIGO's band. Detector designs based on atom interferometry have a number of advantages over traditional approaches in this band, including the possibility of substantially reduced antenna baseline length in space and high isolation from seismic noise for a terrestrial detector. In particular, atom interferometry based on the clock transition in group II atoms offers tantalizing new possibilities. Such a design is expected to be highly immune to laser frequency noise because the signal arises strictly from the light propagation time between two ensembles of atoms. This would allow for a gravitational wave detector with a single linear baseline, potentially offering advantages in cost and design flexibility. In support of these proposals, recent progress in long baseline atom interferometry in a 10-meter drop tower has enabled observation of matter wave interference with atomic wavepacket separations exceeding 50 cm and interferometer durations of more than 2 seconds. This approach can provide ground-based proof-of-concept demonstrations of many of the technical requirements of both terrestrial and satellite gravitational wave detectors.
NASA Astrophysics Data System (ADS)
Kryuchkov, S. V.; Kukhar', E. I.
2015-01-01
The influence of high-frequency electromagnetic radiation on propagation of solitary electromagnetic waves in graphene superlattice is analyzed taking into consideration energy dissipation. The expression for dissipative soliton potential is derived. It is demonstrated that the shape of the dissipative soliton depends on the high-frequency radiation amplitude. Intervals of high-frequency field amplitudes for which two types of dissipative solitons form in graphene superlattice are found. It is shown that areas of these solitons are regulated by variation of the high-frequency radiation amplitude.
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
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.
High frequency computation in wave equations and optimal design for a cavity
NASA Astrophysics Data System (ADS)
Lai, Jun
Two types of problems are studied in this thesis. One part of the thesis is devoted to high frequency computation. Motivated by fast multiscale Gaussian wavepacket transforms and multiscale Gaussian beam methods which were originally designed for initial value problems of wave equations in the high frequency regime, we develop fast multiscale Gaussian beam methods for wave equations in bounded convex domains in the high frequency regime. To compute the wave propagation in bounded convex domains, we have to take into account reflecting multiscale Gaussian beams, which are accomplished by enforcing reflecting boundary conditions during beam propagation and carrying out suitable reflecting beam summation. To propagate multiscale beams efficiently, we prove that the ratio of the squared magnitude of beam amplitude and the beam width is roughly conserved, and accordingly we propose an effective indicator to identify significant beams. We also prove that the resulting multiscale Gaussian beam methods converge asymptotically. Numerical examples demonstrate the accuracy and efficiency of the method. The second part of the thesis studies the reduction of backscatter radar cross section (RCS) for a cavity embedded in the ground plane. One approach for RCS reduction is through the coating material. Assume the bottom of the cavity is coated by a thin, multilayered radar absorbing material (RAM) with possibly different permittivities. The objective is to minimize the backscatter RCS by the incidence of a plane wave over a single or a set of incident angles and frequencies. By formulating the scattering problem as a Helmholtz equation with artificial boundary condition, the gradient with respect to the material permittivities is determined efficiently by the adjoint state method, which is integrated into a nonlinear optimization scheme. Numerical example shows the RCS may be significantly reduced. Another approach is through shape optimization. By introducing a transparent
Gravitational waves in ghost free bimetric gravity
Mohseni, Morteza
2012-11-01
We obtain a set of exact gravitational wave solutions for the ghost free bimetric theory of gravity. With a flat reference metric, the theory admits the vacuum Brinkmann plane wave solution for suitable choices of the coefficients of different terms in the interaction potential. An exact gravitational wave solution corresponding to a massive scalar mode is also admitted for arbitrary choice of the coefficients with the reference metric being proportional to the spacetime metric. The proportionality factor and the speed of the wave are calculated in terms of the parameters of the theory. We also show that a F(R) extension of the theory admits similar solutions but in general is plagued with ghost instabilities.
Simple equations guide high-frequency surface-wave investigation techniques
Xia, J.; Xu, Y.; Chen, C.; Kaufmann, R.D.; Luo, Y.
2006-01-01
We discuss five useful equations related to high-frequency surface-wave techniques and their implications in practice. These equations are theoretical results from published literature regarding source selection, data-acquisition parameters, resolution of a dispersion curve image in the frequency-velocity domain, and the cut-off frequency of high modes. The first equation suggests Rayleigh waves appear in the shortest offset when a source is located on the ground surface, which supports our observations that surface impact sources are the best source for surface-wave techniques. The second and third equations, based on the layered earth model, reveal a relationship between the optimal nearest offset in Rayleigh-wave data acquisition and seismic setting - the observed maximum and minimum phase velocities, and the maximum wavelength. Comparison among data acquired with different offsets at one test site confirms the better data were acquired with the suggested optimal nearest offset. The fourth equation illustrates that resolution of a dispersion curve image at a given frequency is directly proportional to the product of a length of a geophone array and the frequency. We used real-world data to verify the fourth equation. The last equation shows that the cut-off frequency of high modes of Love waves for a two-layer model is determined by shear-wave velocities and the thickness of the top layer. We applied this equation to Rayleigh waves and multi-layer models with the average velocity and obtained encouraging results. This equation not only endows with a criterion to distinguish high modes from numerical artifacts but also provides a straightforward means to resolve the depth to the half space of a layered earth model. ?? 2005 Elsevier Ltd. All rights reserved.
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.
The generation of gravitational waves. IV - Bremsstrahlung
NASA Technical Reports Server (NTRS)
Kovacs, S. J., Jr.; Thorne, K. S.
1978-01-01
Previously derived waveforms for gravitational bremsstrahlung are discussed along with their spectra and their limiting structure at high and low relative velocities. Waveforms and spectra are presented for a low-velocity bremsstrahlung encounter, and waveforms are given for encounters of arbitrary relative velocity. Limiting forms for the gravitational-wave amplitudes in the 'forward', 'intermediate', and 'backward' regions are derived in the high-velocity limit. The energy spectra seen by observers in the three regions are computed for arbitrary and high velocities. Simpler methods for analyzing special cases of the bremsstrahlung problem are examined, and the results of those methods are compared with the present results. Those methods include the quadrupole-moment and post-Newtonian formalisms, linear perturbations of the Schwarzschild metric, the method of colliding plane waves, the method of virtual quanta, and the zero-frequency limit. Classical gravitational bremsstrahlung is then compared with classical electromagnetic bremsstrahlung.
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
The wave energy flux of high frequency diffracting beams in complex geometrical optics
NASA Astrophysics Data System (ADS)
Maj, Omar; Mariani, Alberto; Poli, Emanuele; Farina, Daniela
2013-04-01
We consider the construction of asymptotic solutions of Maxwell's equations for a diffracting wave beam in the high frequency limit and address the description of the wave energy flux transported by the beam. With this aim, the complex eikonal method is applied. That is a generalization of the standard geometrical optics method in which the phase function is assumed to be complex valued, with the non-negative imaginary part accounting for the finite width of the beam cross section. In this framework, we propose an argument which simplifies significantly the analysis of the transport equation for the wave field amplitude and allows us to derive the wave energy flux. The theoretical analysis is illustrated numerically for the case of electron cyclotron beams in tokamak plasmas by using the GRAY code [D. Farina, Fusion Sci. Technol. 52, 154 (2007)], which is based upon the complex eikonal theory. The results are compared to those of the paraxial beam tracing code TORBEAM [E. Poli et al., Comput. Phys. Commun. 136, 90 (2001)], which provides an independent calculation of the energy flow.
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.
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.
Chiral primordial gravitational waves from a Lifshitz point.
Takahashi, Tomohiro; Soda, Jiro
2009-06-12
We study primordial gravitational waves produced during inflation in quantum gravity at a Lifshitz point proposed by Horava. Assuming power-counting renormalizability, foliation-preserving diffeomorphism invariance, and the condition of detailed balance, we show that primordial gravitational waves are circularly polarized due to parity violation. The chirality of primordial gravitational waves is a quite robust prediction of quantum gravity at a Lifshitz point which can be tested through observations of cosmic microwave background radiation and stochastic gravitational waves.
Shilton, Richie J.; Travagliati, Marco; Beltram, Fabio; Cecchini, Marco
2014-08-18
Surface acoustic waves (SAWs) are an effective means to pump fluids through microchannel arrays within fully portable systems. The SAW-driven acoustic counterflow pumping process relies on a cascade phenomenon consisting of SAW transmission through the microchannel, SAW-driven fluid atomization, and subsequent coalescence. Here, we investigate miniaturization of device design, and study both SAW transmission through microchannels and the onset of SAW-driven atomization up to the ultra-high-frequency regime. Within the frequency range from 47.8 MHz to 754 MHz, we show that the acoustic power required to initiate SAW atomization remains constant, while transmission through microchannels is most effective when the channel widths w ≳ 10 λ, where λ is the SAW wavelength. By exploiting the enhanced SAW transmission through narrower channels at ultra-high frequencies, we discuss the relevant frequency-dependent length scales and demonstrate the scaling down of internal flow patterns and discuss their impact on device miniaturization strategies.
Gravitational waves generated by laser accelerated relativistic ions
NASA Astrophysics Data System (ADS)
Gelfer, Evgeny G.; Kadlecová, Hedvika; Klimo, Ondřej; Weber, Stefan; Korn, Georg
2016-09-01
The generation of gravitational waves by laser accelerated relativistic ions is investigated. The piston and light sail models of laser plasma acceleration are considered, and analytical expressions for space-time metric perturbation are derived. For both models, the dependence of gravitational wave amplitude on the laser and plasma parameters as well as gravitational wave spectrum and angular distribution is examined.
NASA Astrophysics Data System (ADS)
Chunping, Zhang; Wei, Liu; Zhichun, Yang; Zhengyu, Li; Xiaoqing, Zhang; Feng, Wu
2012-05-01
A small size standing wave thermoacoustic refrigerator driven by a high frequency loudspeaker has been experimentally studied. Instead of water cooling, the cold heat exchanger of the refrigerator was cooled by air through fins on it. By working at 600-700 Hz and adjusting the position of the thermoacoustic core components including the stack and adjacent exchangers, the influences of it on the capability of refrigeration were experimentally investigated. The lowest temperature of 4.1 °C in the cold heat exchanger with the highest temperature difference of 21.5 °C between two heat exchangers were obtained. And the maximum cooling power of 9.7 W has been achieved.
Michaud, Mark; Leong, Thomas; Swiergon, Piotr; Juliano, Pablo; Knoerzer, Kai
2015-09-01
This work validated, in a higher frequency range, the theoretical predictions made by Boyle around 1930, which state that the optimal transmission of sound pressure through a metal plate occurs when the plate thickness equals a multiple of half the wavelength of the sound wave. Several reactor design parameters influencing the transmission of high frequency ultrasonic waves through a stainless steel plate were examined. The transmission properties of steel plates of various thicknesses (1-7 mm) were studied for frequencies ranging from 400 kHz to 2 MHz and at different distances between plates and transducers. It was shown that transmission of sound pressure through a steel plate showed high dependence of the thickness of the plate to the frequency of the sound wave (thickness ratio). Maximum sound pressure transmission of ∼ 60% of the incident pressure was observed when the ratio of the plate thickness to the applied frequency was a multiple of a half wavelength (2 MHz, 6mm stainless steel plate). In contrast, minimal sound pressure transmission (∼ 10-20%) was measured for thickness ratios that were not a multiple of a half wavelength. Furthermore, the attenuation of the sound pressure in the transmission region was also investigated. As expected, it was confirmed that higher frequencies have more pronounced sound pressure attenuation than lower frequencies. The spatial distribution of the sound pressure transmitted through the plate characterized by sonochemiluminescence measurements using luminol emission, supports the validity of the pressure measurements in this study.
Testing gravity with gravitational wave source counts
NASA Astrophysics Data System (ADS)
Calabrese, Erminia; Battaglia, Nicholas; Spergel, David N.
2016-08-01
We show that the gravitational wave source counts distribution can test how gravitational radiation propagates on cosmological scales. This test does not require obtaining redshifts for the sources. If the signal-to-noise ratio (ρ) from a gravitational wave source is proportional to the strain then it falls as {R}-1, thus we expect the source counts to follow {{d}}{N}/{{d}}ρ \\propto {ρ }-4. However, if gravitational waves decay as they propagate or propagate into other dimensions, then there can be deviations from this generic prediction. We consider the possibility that the strain falls as {R}-γ , where γ =1 recovers the expected predictions in a Euclidean uniformly-filled Universe, and forecast the sensitivity of future observations to deviations from standard General Relativity. We first consider the case of few objects, seven sources, with a signal-to-noise from 8 to 24, and impose a lower limit on γ, finding γ \\gt 0.33 at 95% confidence level. The distribution of our simulated sample is very consistent with the distribution of the trigger events reported by Advanced LIGO. Future measurements will improve these constraints: with 100 events, we estimate that γ can be measured with an uncertainty of 15%. We generalize the formalism to account for a range of chirp masses and the possibility that the signal falls as {exp}(-R/{R}0)/{R}γ .
Quantum metrology for gravitational wave astronomy.
Schnabel, Roman; Mavalvala, Nergis; McClelland, David E; Lam, Ping K
2010-11-16
Einstein's general theory of relativity predicts that accelerating mass distributions produce gravitational radiation, analogous to electromagnetic radiation from accelerating charges. These gravitational waves (GWs) have not been directly detected to date, but are expected to open a new window to the Universe once the detectors, kilometre-scale laser interferometers measuring the distance between quasi-free-falling mirrors, have achieved adequate sensitivity. Recent advances in quantum metrology may now contribute to provide the required sensitivity boost. The so-called squeezed light is able to quantum entangle the high-power laser fields in the interferometer arms, and could have a key role in the realization of GW astronomy.
Quantum metrology for gravitational wave astronomy.
Schnabel, Roman; Mavalvala, Nergis; McClelland, David E; Lam, Ping K
2010-01-01
Einstein's general theory of relativity predicts that accelerating mass distributions produce gravitational radiation, analogous to electromagnetic radiation from accelerating charges. These gravitational waves (GWs) have not been directly detected to date, but are expected to open a new window to the Universe once the detectors, kilometre-scale laser interferometers measuring the distance between quasi-free-falling mirrors, have achieved adequate sensitivity. Recent advances in quantum metrology may now contribute to provide the required sensitivity boost. The so-called squeezed light is able to quantum entangle the high-power laser fields in the interferometer arms, and could have a key role in the realization of GW astronomy. PMID:21081919
On-board processing of high frequency plasma wave measurements on Solar Orbiter RPW instrument
NASA Astrophysics Data System (ADS)
Soucek, J.; Uhlir, L.; Santolik, O.; Kolmasova, I.; Lan, R.
2013-09-01
The Radio and Plasma Wave (RPW) instrument of the Solar Orbiter spacecraft will include a Time Domain Sampler module (TDS) dedicated to electromagnetic waveform measurements from about 100 Hz to 500 kHz. The primary science objective of the instrument is in-situ measurement of solar wind Langmuir waves associated with solar bursts and interplanetary shocks and the process of their conversion to electromagnetic radiation. Langmuir waves are observed at relatively high frequency (10-100 kHz) and appear in the form of short bursts (Fig. 1). A secondary science objective of TDS is the detection voltage spikes often observed on electric field antennas as a result of an impact of dust particle on the spacecraft (Fig. 2). Both phenomena are relatively rare and the data volume associated with the measurement is very large. On board detection and pre-processing of the data can thus greatly reduce the telemetry requirements and increase the science return of the experiment. The instrument implements an advanced on-board digital signal processor which allows for preprocessing of captured waveform data by configurable digital filters and basic analysis of waveform snapshots (identification of wave packets and electric field signatures of impacts of dust particles on the spacecraft, calculation of basic signal characteristics). The results of the on-board analysis are used to select interesting wave events for downlink and to collect statistics on observed snapshots which cannot be transmitted to ground. The data filtering and decimation are implemented in FPGA firmware and the more complicated data processing is performed in software running on Leon 3 CPU. We present the design of the instrument, basic overview of the algorithms used in event identification, and the assessment of their erformance on test datasets based data from STEREO spacecraft.
Standing gravitational waves from domain walls
Gogberashvili, Merab; Myrzakul, Shynaray; Singleton, Douglas
2009-07-15
We construct a plane symmetric, standing gravitational wave for a domain wall plus a massless scalar field. The scalar field can be associated with a fluid which has the properties of 'stiff' matter, i.e., matter in which the speed of sound equals the speed of light. Although domain walls are observationally ruled out in the present era, the solution has interesting features which might shed light on the character of exact nonlinear wave solutions to Einstein's equations. Additionally this solution may act as a template for higher dimensional 'brane-world' model standing waves.
Detectability of inflationary gravitational waves with microwave background polarization
Kamionkowski, M.; Kosowsky, A. |
1998-01-01
Inflation predicts specific relations between the amplitudes and spectral indices of the primordial spectrum of density (scalar metric) perturbations and gravitational waves (tensor metric perturbations). Detection of a stochastic gravitational-wave background is essential for identifying this unmistakable signature. Polarization of the cosmic microwave background can isolate these tensor modes in a model-independent way and thereby circumvent the cosmic-variance limit to detecting a small tensor signal with only a temperature map. Here we assess the detectability of a gravity-wave background with a temperature and polarization map. For detector sensitivities better than 10{endash}20{mu}K{radical} (sec) , the sensitivity to a tensor signal is always dominated by the polarization map. With a detector sensitivity of order 1{mu}K{radical} (sec) , polarization could improve on a temperature-map sensitivity to tensor modes by two to three orders of magnitude. Even a small amount of reionization substantially enhances tensor-mode detectability. We also argue that the sensitivity of the Planck Surveyor to tensor modes is significantly improved with polarization, even taking into account the resulting degradation of the intensity determination in the high-frequency channels. {copyright} {ital 1997} {ital The American Physical Society}
NASA Astrophysics Data System (ADS)
Song, Xianhai; Li, Lei; Zhang, Xueqiang; Huang, Jianquan; Shi, Xinchun; Jin, Si; Bai, Yiming
2014-10-01
to nonlinear inversion of high-frequency surface wave data should be considered good not only in terms of the accuracy but also in terms of the convergence speed.
Seto, Naoki
2009-11-15
Gravitational waves (GWs) from cosmological double neutron star binaries (NS+NS) can be significantly demagnified by the strong gravitational lensing effect, and the proposed future missions such as the Big Bang Observer or Deci-hertz Interferometer Gravitational Wave Observatory might miss some of the demagnified GW signals below a detection threshold. The undetectable binaries would form a GW foreground, which might hamper detection of a very weak primordial GW signal. We discuss the outlook of this potential problem, using a simple model based on the singular isothermal sphere lens profile. Fortunately, it is expected that, for a presumable merger rate of NS+NSs, the residual foreground would be below the detection limit {omega}{sub GW,lim}{approx}10{sup -16} realized with the Big Bang Observer/Deci-hertz Interferometer Gravitational Wave Observatory by correlation analysis.
Gravitational waves: Perspectives of detection
NASA Astrophysics Data System (ADS)
Cerdonio, Massimo
2015-01-01
With Giovanni Losurdo, the PI of Advanced Virgo, we recently dwelled on this subject in an invited review paper [#!ncc10890bib1!#]. Here I first give a short introduction by answering in brief to a few basic and relevant questions, which I was often asked by colleagues not specifically working on gravitation. Then I highlight the main considerations discussed in [#!ncc10890bib1!#], in a sort of guide for the reader, where more details and an extensive reference list can be found. For more complete info, I call the attention to a number of beautiful pictures, kindly provided by my colleagues, which I put on the IFAE website, but are not given here nor in [#!ncc10890bib1!#]. After publication of [#!ncc10890bib1!#], a few relevant developments occurred, especially in the long-term planning of experiments, on which I report here. To update the references would have resulted in adding some sort of ten percent more than those in [#!ncc10890bib1!#], so I have added only a few, which I rate most recent and particularly relevant to the relative issue.
Gravitational wave searches using the DSN (Deep Space Network)
NASA Technical Reports Server (NTRS)
Nelson, S. J.; Armstrong, J. W.
1988-01-01
The Deep Space Network Doppler spacecraft link is currently the only method available for broadband gravitational wave searches in the 0.01 to 0.001 Hz frequency range. The DSN's role in the worldwide search for gravitational waves is described by first summarizing from the literature current theoretical estimates of gravitational wave strengths and time scales from various astrophysical sources. Current and future detection schemes for ground based and space based detectors are then discussed. Past, present, and future planned or proposed gravitational wave experiments using DSN Doppler tracking are described. Lastly, some major technical challenges to improve gravitational wave sensitivities using the DSN are discussed.
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.
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.
Gravitational Wave Astronomy and Constraints on Binary Synthesis
NASA Astrophysics Data System (ADS)
Kalogera, V.
2004-12-01
In the coming decade gravitational-wave astronomy is expected to develop as a new field of astronomical research and exploration of the cosmos. In this talk I summarize the outcome of a recent workshop ``Imagining the Future: Gravitational Wave Astronomy" and discuss a specific example of how gravitational-wave observations could be used in the future to improve our understanding of binary evolution and compact objects. This work is partially supported by NSF Gravitational Physics Program and a NASA ATP awards.
CMB μ distortion from primordial gravitational waves
Ota, Atsuhisa; Yamaguchi, Masahide; Takahashi, Tomo; Tashiro, Hiroyuki E-mail: tomot@cc.saga-u.ac.jp E-mail: gucci@phys.titech.ac.jp
2014-10-01
We propose a new mechanism of generating the μ distortion in cosmic microwave background (CMB) originated from primordial gravitational waves. Such μ distortion is generated by the damping of the temperature anisotropies through the Thomson scattering, even on scales larger than that of Silk damping. This mechanism is in sharp contrast with that from the primordial curvature (scalar) perturbations, in which the temperature anisotropies mainly decay by Silk damping effects. We estimate the size of the μ distortion from the new mechanism, which can be used to constrain the amplitude of primordial gravitational waves on smaller scales independently from the CMB anisotropies, giving more wide-range constraint on their spectral index by combining the amplitude from the CMB anisotropies.
Gravitational wave memory in an expanding universe
NASA Astrophysics Data System (ADS)
Tolish, Alexander; Wald, Robert
2016-03-01
We investigate the gravitational wave memory effect in an expanding FLRW spacetime. We find that if the gravitational field is decomposed into gauge-invariant scalar, vector, and tensor modes after the fashion of Bardeen, only the tensor mode gives rise to memory, and this memory can be calculated using the retarded Green's function associated with the tensor wave equation. If locally similar radiation source events occur on flat and FLRW backgrounds, we find that the resulting memories will differ only by a redshift factor, and we explore whether or not this factor depends on the expansion history of the FLRW universe. We compare our results to related work by Bieri, Garfinkle, and Yau.
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.
Gravitational Waves from Core Collapse Supernovae
Yakunin, Konstantin; Marronetti, Pedro; Mezzacappa, Anthony; Bruenn, S. W.; Lee, Ching-Tsai; Chertkow, Merek A; Hix, William Raphael; Blondin, J. M.; Lentz, Eric J; Messer, Bronson; Yoshida, S.
2010-01-01
We present the gravitational wave signatures for a suite of axisymmetric core collapse supernova models with progenitor masses between 12 and 25 M{sub odot}. These models are distinguished by the fact that they explode and contain essential physics (in particular, multi-frequency neutrino transport and general relativity) needed for a more realistic description. Thus, we are able to compute complete waveforms (i.e. through explosion) based on non-parameterized, first-principles models. This is essential if the waveform amplitudes and time scales are to be computed more precisely. Fourier decomposition shows that the gravitational wave signals we predict should be observable by AdvLIGO across the range of progenitors considered here. The fundamental limitation of these models is in their imposition of axisymmetry. Further progress will require counterpart three-dimensional models.
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.
Garfinkle, David; Pretorius, Frans; Yunes, Nicolas
2010-08-15
We perform a linear stability analysis of dynamical Chern-Simons modified gravity in the geometric optics approximation and find that it is linearly stable on the backgrounds considered. Our analysis also reveals that gravitational waves in the modified theory travel at the speed of light in Minkowski spacetime. However, on a Schwarzschild background the characteristic speed of propagation along a given direction splits into two modes, one subluminal and one superluminal. The width of the splitting depends on the azimuthal components of the propagation vector, is linearly proportional to the mass of the black hole, and decreases with the third inverse power of the distance from the black hole. Radial propagation is unaffected, implying that as probed by gravitational waves the location of the event horizon of the spacetime is unaltered. The analysis further reveals that when a high frequency, pure gravitational wave is scattered from a black hole, a scalar wave of comparable amplitude is excited, and vice versa.
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.
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.
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 an inflationary to a radiation-dominated universe is accomplished by bubble nucleation, bubble collisions supply a potent - and potentially detectable - source of gravitational waves. The energy density in relic gravitons from bubble collisions is expected to be about 0.00005 of closure density. Their characteristic wavelength depends on the reheating temperature. If black holes are produced by bubble collisions, they will evaporate, producing shorter-wavelength gravitons.
Separating gravitational wave signals from instrument artifacts
Littenberg, Tyson B.; Cornish, Neil J.
2010-11-15
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 transdimensional 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 nonstationary 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.
Gravitational waves from the big bounce
Mielczarek, Jakub
2008-11-15
In this paper we investigate gravitational wave production during the big bounce phase, inspired by loop quantum cosmology. We consider the influence of the holonomy corrections to the equation for tensor modes. We show that they act like additional effective graviton mass, suppressing gravitational wave creation. However, such effects can be treated perturbatively. We investigate a simplified model without holonomy corrections to the equation for modes and find its exact analytical solution. Assuming the form for matter {rho}{proportional_to}a{sup -2} we calculate the full spectrum of the gravitational waves from the big bounce phase. The spectrum obtained decreases to zero for the low energy modes. On the basis of this observation we infer that this effect can lead to low cosmic microwave background (CMB) multipole suppression and gives a potential way for testing loop quantum cosmology models. We also consider a scenario with a post-bounce inflationary phase. The power spectrum obtained gives a qualitative explanation of the CMB spectra, including low multipole suppression.
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 .
LIGO and the Search for Gravitational Waves
Robertson, Norna A.
2006-10-16
Gravitational waves, predicted to exist by Einstein’s General Theory of Relativity but as yet undetected, are expected to be emitted during violent astrophysical events such as supernovae, black hole interactions and the coalescence of compact binary systems. Their detection and study should lead to a new branch of astronomy. However the experimental challenge is formidable: ground-based detection relies on sensing displacements of order 10^-18 m over a frequency range of tens of hertz to a few kHz. There is currently a large international effort to commission and operate long baseline interferometric detectors including those that comprise LIGO - the Laser Interferometer Gravitational-Wave Observatory - in the USA. In this talk I will give an introduction to the topic of gravitational wave detection and in particular review the status of the LIGO project which is currently taking data at its design sensitivity. I will also look to the future to consider planned improvements in sensitivity for such detectors, focusing on Advanced LIGO, the proposed upgrade to the LIGO project
LIGO and the Search for Gravitational Waves
Robertson, Norna A.
2006-10-16
Gravitational waves, predicted to exist by Einstein's General Theory of Relativity but as yet undetected, are expected to be emitted during violent astrophysical events such as supernovae, black hole interactions and the coalescence of compact binary systems. Their detection and study should lead to a new branch of astronomy. However the experimental challenge is formidable: ground-based detection relies on sensing displacements of order 10{sup -18} m over a frequency range of tens of hertz to a few kHz. There is currently a large international effort to commission and operate long baseline interferometric detectors including those that comprise LIGO - the Laser Interferometer Gravitational-Wave Observatory - in the USA. In this talk I will give an introduction to the topic of gravitational wave detection and in particular review the status of the LIGO project which is currently taking data at its design sensitivity. I will also look to the future to consider planned improvements in sensitivity for such detectors, focusing on Advanced LIGO, the proposed upgrade to the LIGO project.
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.
Gravitational Waves from Black Hole Mergers
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based interferometer LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, data analysis, and astrophysics.
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).
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.
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.
Remote sensing of surface currents with single shipborne high-frequency surface wave radar
NASA Astrophysics Data System (ADS)
Wang, Zhongbao; Xie, Junhao; Ji, Zhenyuan; Quan, Taifan
2016-01-01
High-frequency surface wave radar (HFSWR) is a useful technology for remote sensing of surface currents. It usually requires two (or more) stations spaced apart to create a two-dimensional (2D) current vector field. However, this method can only obtain the measurements within the overlapping coverage, which wastes most of the data from only one radar observation. Furthermore, it increases observation's costs significantly. To reduce the number of required radars and increase the ocean area that can be measured, this paper proposes an economical methodology for remote sensing of the 2D surface current vector field using single shipborne HFSWR. The methodology contains two parts: (1) a real space-time multiple signal classification (MUSIC) based on sparse representation and unitary transformation techniques is developed for measuring the radial currents from the spreading first-order spectra, and (2) the stream function method is introduced to obtain the 2D surface current vector field. Some important conclusions are drawn, and simulations are included to validate the correctness of them.
Tsujimura, Shinichi; Yamagishi, Hiroto; Sankai, Yoshiyuki
2009-01-01
In order to minimize infection risks of patients with artificial hearts, wireless data transmission methods with electromagnetic induction or light have been developed. However, these methods tend to become difficult to transmit data if the external data transmission unit moves from its proper position. To resolve this serious problem, the purpose of this study is to develop a prototype wireless data communication system with ultra high frequency radio wave and confirm its performance. Due to its high-speed communication rate, low power consumption, high tolerance to electromagnetic disturbances, and secure wireless communication, we adopted Bluetooth radio wave technology for our system. The system consists of an internal data transmission unit and an external data transmission unit (53 by 64 by 16 mm, each), and each has a Bluetooth module (radio field intensity: 4 dBm, receiver sensitivity: -80 dBm). The internal unit also has a micro controller with an 8-channel 10-bit A/D converter, and the external unit also has a RS-232C converter. We experimented with the internal unit implanted into pig meat, and carried out data transmission tests to evaluate the performance of this system in tissue thickness of up to 3 mm. As a result, data transfer speeds of about 20 kbps were achieved within the communication distance of 10 m. In conclusion, we confirmed that the system can wirelessly transmit the data from the inside of the body to the outside, and it promises to resolve unstable data transmission due to accidental movements of an external data transmission unit. PMID:19964616
Kuo, Spencer; Snyder, Arnold; Chang, Chia-Lie
2010-08-15
Results of extremely low frequency/very low frequency (ELF/VLF) wave generation by intensity-modulated high frequency (HF) heaters of 3.2 MHz in Gakona, Alaska, near local solar noon during a geomagnetic quiet time, are presented to support an electrojet-independent ELF/VLF wave generation mechanism. The modulation was set by splitting the HF transmitter array into two subarrays; one was run at cw full power and the other run alternatively at 50% and 100% power modulation by rectangular waves of 2.02, 5, 8, and 13 kHz. The most effective generation was from the X-mode heater with 100% modulation. While the 8 kHz radiation has the largest wave amplitude, the spectral intensity of the radiation increases with the modulation frequency, i.e., 13 kHz line is the strongest. Ionograms recorded significant virtual height spread of the O-mode sounding echoes. The patterns of the spreads and the changes of the second and third hop virtual height traces caused by the O/X-mode heaters are distinctively different, evidencing that it is due to differently polarized density irregularities generated by the filamentation instability of the O/X-mode HF heaters.
Gravitational waves from the electroweak phase transition
Leitao, Leonardo; Mégevand, Ariel; Sánchez, Alejandro D. E-mail: megevand@mdp.edu.ar
2012-10-01
We study the generation of gravitational waves in the electroweak phase transition. We consider a few extensions of the Standard Model, namely, the addition of scalar singlets, the minimal supersymmetric extension, and the addition of TeV fermions. For each model we consider the complete dynamics of the phase transition. In particular, we estimate the friction force acting on bubble walls, and we take into account the fact that they can propagate either as detonations or as deflagrations preceded by shock fronts, or they can run away. We compute the peak frequency and peak intensity of the gravitational radiation generated by bubble collisions and turbulence. We discuss the detectability by proposed spaceborne detectors. For the models we considered, runaway walls require significant fine tuning of the parameters, and the gravitational wave signal from bubble collisions is generally much weaker than that from turbulence. Although the predicted signal is in most cases rather low for the sensitivity of LISA, models with strongly coupled extra scalars reach this sensitivity for frequencies f ∼ 10{sup −4} Hz, and give intensities as high as h{sup 2}Ω{sub GW} ∼ 10{sup −8}.
Modulation of a chirp gravitational wave from a compact binary due to gravitational lensing
Yamamoto, Kazuhiro
2005-05-15
A possible wave effect in the gravitational lensing phenomenon is discussed. We consider the interference of two coherent gravitational waves of slightly different frequencies from a compact binary, due to the gravitational lensing by a galaxy halo. This system shows the modulation of the wave amplitude. The lensing probability of such the phenomenon is of order 10{sup -5} for a high-z source, but it may be advantageous to the observation due to the magnification of the amplitude.
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.
Gravitational waves from a curvaton model with blue spectrum
Kawasaki, Masahiro; Kitajima, Naoya; Yokoyama, Shuichiro E-mail: nk610@icrr.u-tokyo.ac.jp
2013-08-01
We investigate the gravitational wave background induced by the first order scalar perturbations in the curvaton models. We consider the quadratic and axion-like curvaton potential which can generate the blue-tilted power spectrum of curvature perturbations on small scales and derive the maximal amount of gravitational wave background today. We find the power spectrum of the induced gravitational wave background has a characteristic peak at the frequency corresponding to the scale reentering the horizon at the curvaton decay, in the case where the curvaton does not dominate the energy density of the Universe. We also find the enhancement of the amount of the gravitational waves in the case where the curvaton dominates the energy density of the Universe. Such induced gravitational waves would be detectable by the future space-based gravitational wave detectors or pulsar timing observations.
Kim, Hoe Woong; Cho, Seung Hyun; Kim, Yoon Young
2011-08-01
Recently, megahertz-range torsional waves have been successfully generated and measured by a magnetostrictive patch transducer employing a meander coil. But the waveform of a high-frequency torsional wave generated by magnetostrictive patch transducers becomes greatly distorted with multiple trailing pulses. The hypothesis explaining the cause of the waveform distortion is that the distortion results mainly from the internal wave reflection within the magnetostrictive patch, which is in turn caused by the impedance mismatch between the bare and patch-bonded parts of the pipe. Based on the hypothesis, we developed an analytic model for internal reflection simulation and conducted several experiments using a patch transducer to verify the hypothesis. The comparison of the analytical and experimental results showed that the internal reflection at the edge of the patch was responsible for the distortion of the measured waveform. The present study also confirmed that the standard acoustic impedance matching to avoid sudden discontinuities at the patch edges can effectively reduce the internal reflection and alleviate the waveform distortion problem. PMID:21420708
Kim, Hoe Woong; Cho, Seung Hyun; Kim, Yoon Young
2011-08-01
Recently, megahertz-range torsional waves have been successfully generated and measured by a magnetostrictive patch transducer employing a meander coil. But the waveform of a high-frequency torsional wave generated by magnetostrictive patch transducers becomes greatly distorted with multiple trailing pulses. The hypothesis explaining the cause of the waveform distortion is that the distortion results mainly from the internal wave reflection within the magnetostrictive patch, which is in turn caused by the impedance mismatch between the bare and patch-bonded parts of the pipe. Based on the hypothesis, we developed an analytic model for internal reflection simulation and conducted several experiments using a patch transducer to verify the hypothesis. The comparison of the analytical and experimental results showed that the internal reflection at the edge of the patch was responsible for the distortion of the measured waveform. The present study also confirmed that the standard acoustic impedance matching to avoid sudden discontinuities at the patch edges can effectively reduce the internal reflection and alleviate the waveform distortion problem.
A new gravitational wave verification source
NASA Astrophysics Data System (ADS)
Kilic, Mukremin; Brown, Warren R.; Gianninas, A.; Hermes, J. J.; Allende Prieto, Carlos; Kenyon, S. J.
2014-10-01
We report the discovery of a detached 20-min orbital period binary white dwarf (WD). WD 0931+444 (SDSS J093506.93+441106.9) was previously classified as a WD + M dwarf system based on its optical spectrum. Our time-resolved optical spectroscopy observations obtained at the 8 m Gemini and 6.5 m MMT reveal peak-to-peak radial velocity variations of ≈400 km s-1 every 20 min for the WD, but no velocity variations for the M dwarf. In addition, high-speed photometry from the McDonald 2.1 m telescope shows no evidence of variability nor evidence of a reflection effect. An M dwarf companion is physically too large to fit into a 20 min orbit. Thus, the orbital motion of the WD is almost certainly due to an invisible WD companion. The M dwarf must be either an unrelated background object or the tertiary component of a hierarchical triple system. WD 0931+444 contains a pair of WDs, a 0.32 M⊙ primary and a ≥0.14 M⊙ secondary, at a separation of ≥0.19 R⊙. After J0651+2844, WD 0931+444 becomes the second shortest period detached binary WD currently known. The two WDs will lose angular momentum through gravitational wave radiation and merge in ≤9 Myr. The log h ≃ -22 gravitational wave strain from WD 0931+444 is strong enough to make it a verification source for gravitational wave missions in the milli-Hertz frequency range, e.g. the evolved Laser Interferometer Space Antenna (eLISA), bringing the total number of known eLISA verification sources to nine.
NASA Astrophysics Data System (ADS)
Hatakeyama, Norishige; Uchida, Naoki; Matsuzawa, Toru; Okada, Tomomi; Nakajima, Junichi; Matsushima, Takeshi; Kono, Toshio; Hirahara, Satoshi; Nakayama, Takashi
2016-11-01
We examined the variation in the high-frequency wave radiation for three repeating earthquake sequences (M = 3.1-4.1) in the northeastern Japan subduction zone by waveform analyses. Earthquakes in each repeating sequence are located at almost the same place and show low-angle thrust type focal mechanisms, indicating that they represent repeated ruptures of a seismic patch on the plate boundary. We calculated cross-spectra of the waveforms and obtained the phases and coherences for pairs of events in the respective repeating sequences in order to investigate the waveform differences. We used waveform data sampled at 1 kHz that were obtained from temporary seismic observations we conducted immediately after the 2011 Tohoku earthquake near the source area. For two repeating sequences, we found that the interevent delay times for the two waveforms in a frequency band higher than the corner frequencies are different from those in a lower frequency band for particular event pairs. The phases and coherences show that there are coherent high-frequency waves for almost all the repeaters regardless of the high-frequency delays. These results indicate that high-frequency waves are always radiated from the same vicinity (subpatch) for these events but the time intervals between the ruptures of the subpatch and the centroid times can vary. We classified events in the sequence into two subgroups according to the high-frequency band interevent delays relative to the low-frequency band. For one sequence, we found that all the events that occurred just after (within 11 days) larger nearby earthquakes belong to one subgroup while other events belong to the other subgroup. This suggests that the high-frequency wave differences were caused by stress perturbations due to the nearby earthquakes. In summary, our observations suggest that high-frequency waves from the repeating sequence are radiated not from everywhere but from a long-duration subpatch within the seismic slip area. The
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...''
Gravitational waves from neutron-star mergers
NASA Astrophysics Data System (ADS)
Read, Jocelyn; Cullen, Torrey; Flynn, Eric; Lockett-Ruiz, Veronica; Park, Conner; Vong, Susan
2016-03-01
The inspiral and merger of binary neutron stars is expected to provide many signals for Advanced LIGO at design sensitivity. The waveform models currently used to search for and parameterize these signals ignore effects near the merger: as the stars coalesce, the gravitational waves depend additionally on the properties of matter in the core of the stars. In this talk, I will discuss potential systematic error from neglecting these features and present phenomenological waveform models currently being developed to capture the dynamics of merging neutron stars.
Gravitational waves from self-ordering scalar fields
Fenu, Elisa; Durrer, Ruth; Figueroa, Daniel G.; García-Bellido, Juan E-mail: daniel.figueroa@uam.es E-mail: juan.garciabellido@uam.es
2009-10-01
Gravitational waves were copiously produced in the early Universe whenever the processes taking place were sufficiently violent. The spectra of several of these gravitational wave backgrounds on subhorizon scales have been extensively studied in the literature. In this paper we analyze the shape and amplitude of the gravitational wave spectrum on scales which are superhorizon at the time of production. Such gravitational waves are expected from the self ordering of randomly oriented scalar fields which can be present during a thermal phase transition or during preheating after hybrid inflation. We find that, if the gravitational wave source acts only during a small fraction of the Hubble time, the gravitational wave spectrum at frequencies lower than the expansion rate at the time of production behaves as Ω{sub GW}(f) ∝ f{sup 3} with an amplitude much too small to be observable by gravitational wave observatories like LIGO, LISA or BBO. On the other hand, if the source is active for a much longer time, until a given mode which is initially superhorizon (kη{sub *} << 1), enters the horizon, for kη ∼> 1, we find that the gravitational wave energy density is frequency independent, i.e. scale invariant. Moreover, its amplitude for a GUT scale scenario turns out to be within the range and sensitivity of BBO and marginally detectable by LIGO and LISA. This new gravitational wave background can compete with the one generated during inflation, and distinguishing both may require extra information.
Gravitational-wave stochastic background from cosmic strings.
Siemens, Xavier; Mandic, Vuk; Creighton, Jolien
2007-03-16
We consider the stochastic background of gravitational waves produced by a network of cosmic strings and assess their accessibility to current and planned gravitational wave detectors, as well as to big bang nucleosynthesis (BBN), cosmic microwave background (CMB), and pulsar timing constraints. We find that current data from interferometric gravitational wave detectors, such as Laser Interferometer Gravitational Wave Observatory (LIGO), are sensitive to areas of parameter space of cosmic string models complementary to those accessible to pulsar, BBN, and CMB bounds. Future more sensitive LIGO runs and interferometers such as Advanced LIGO and Laser Interferometer Space Antenna (LISA) will be able to explore substantial parts of the parameter space. PMID:17501038
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%.
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.
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. PMID:23277598
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.
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.
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.
Gravitational waves from preheating in M-flation
Ashoorioon, Amjad; Fung, Brandon; Mann, Robert B.; Oltean, Marius; Sheikh-Jabbari, M.M. E-mail: b6fung@uwaterloo.ca E-mail: moltean@physics.mcgill.ca
2014-03-01
Matrix inflation, or M-flation, is a string theory motivated inflationary model with three scalar field matrices and gauge fields in the adjoint representation of the U(N) gauge group. One of these 3N{sup 2} scalars appears as the effective inflaton while the rest of the fields (scalar and gauge fields) can play the role of isocurvature fields during inflation and preheat fields afterwards. There is a region in parameter space and initial field values, ''the hilltop region'', where predictions of the model are quite compatible with the recent Planck data. We show that in this hilltop region, if the inflaton ends up in the supersymmetric vacuum, the model can have an embedded preheating mechanism. Couplings of the preheat modes are related to the inflaton self-couplings and therefore are known from the CMB data. Through lattice simulations performed using a symplectic integrator, we numerically compute the power spectra of gravitational waves produced during the preheating stage following M-flation. The preliminary numerical simulation of the spectrum from multi-preheat fields peaks in the GHz band with an amplitude Ω{sub gw}h{sup 2}∝10{sup −16}, suggesting that the model has concrete predictions for the ultra-high frequency gravity-wave probes. This signature could be used to distinguish the model from rival inflationary models.
Gravitational-wave detection using redshifted 21-cm observations
Bharadwaj, Somnath; Guha Sarkar, Tapomoy
2009-06-15
A gravitational-wave traversing the line of sight to a distant source produces a frequency shift which contributes to redshift space distortion. As a consequence, gravitational waves are imprinted as density fluctuations in redshift space. The gravitational-wave contribution to the redshift space power spectrum has a different {mu} dependence as compared to the dominant contribution from peculiar velocities. This, in principle, allows the two signals to be separated. The prospect of a detection is most favorable at the highest observable redshift z. Observations of redshifted 21-cm radiation from neutral hydrogen hold the possibility of probing very high redshifts. We consider the possibility of detecting primordial gravitational waves using the redshift space neutral hydrogen power spectrum. However, we find that the gravitational-wave signal, though present, will not be detectable on superhorizon scales because of cosmic variance and on subhorizon scales where the signal is highly suppressed.
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.
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.
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.
Transmission of high frequency sound waves through a slug flow jet
NASA Technical Reports Server (NTRS)
Parthasarathy, S. P.; Vijayaraghavan, A.
1980-01-01
An analysis has been performed of sound waves which propagate in a pipe with gas flow. At the pipe exit these waves are partially reflected and the remainder are diffracted. The analysis is carried out by resolving the sound at the exit into its Fourier components and then continuing the solution, which is a combination of elementary plane waves, beyond the exit. These waves are of two types: homogeneous waves which propagate to infinity, and inhomogeneous waves with complex wave numbers which decay. The reflected waves are evaluated from the inhomogeneous waves. At the boundary of the jet, refraction of the elementary plane waves is accounted for and the far field sound is evaluated by the method of stationary phase. Comparisons of the theoretical calculations are made with experimental results and with calculations of other theories.
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.
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.
Constraining the braneworld with gravitational wave observations.
McWilliams, Sean T
2010-04-01
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 microm level for optimal cases, while the observation of a single galactic black hole binary with LISA results in an optimal constraint of l < or = 5 microm. PMID:20481929
Optimal directed searches for continuous gravitational waves
NASA Astrophysics Data System (ADS)
Ming, Jing; Krishnan, Badri; Papa, Maria Alessandra; Aulbert, Carsten; Fehrmann, Henning
2016-03-01
Wide parameter space searches for long-lived continuous gravitational wave signals are computationally limited. It is therefore critically important that the available computational resources are used rationally. In this paper we consider directed searches, i.e., targets for which the sky position is known accurately but the frequency and spin-down parameters are completely unknown. Given a list of such potential astrophysical targets, we therefore need to prioritize. On which target(s) should we spend scarce computing resources? What parameter space region in frequency and spin-down should we search through? Finally, what is the optimal search setup that we should use? In this paper we present a general framework that allows us to solve all three of these problems. This framework is based on maximizing the probability of making a detection subject to a constraint on the maximum available computational cost. We illustrate the method for a simplified problem.
Interaction of gravitational waves with magnetic and electric fields
Barrabes, C.; Hogan, P. A.
2010-03-15
The existence of large-scale magnetic fields in the universe has led to the observation that if gravitational waves propagating in a cosmological environment encounter even a small magnetic field then electromagnetic radiation is produced. To study this phenomenon in more detail we take it out of the cosmological context and at the same time simplify the gravitational radiation to impulsive waves. Specifically, to illustrate our findings, we describe the following three physical situations: (1) a cylindrical impulsive gravitational wave propagating into a universe with a magnetic field, (2) an axially symmetric impulsive gravitational wave propagating into a universe with an electric field and (3) a 'spherical' impulsive gravitational wave propagating into a universe with a small magnetic field. In cases (1) and (3) electromagnetic radiation is produced behind the gravitational wave. In case (2) no electromagnetic radiation appears after the wave unless a current is established behind the wave breaking the Maxwell vacuum. In all three cases the presence of the magnetic or electric fields results in a modification of the amplitude of the incoming gravitational wave which is explicitly calculated using the Einstein-Maxwell vacuum field equations.
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.
Searching for gravitational waves from neutron stars
NASA Astrophysics Data System (ADS)
Idrisy, Ashikuzzaman
In this dissertation we discuss gravitational waves (GWs) and their neutron star (NS) sources. We begin with a general discussion of the motivation for searching for GWs and the indirect experimental evidence of their existence. Then we discuss the various mechanisms through which NS can emit GWs, paying special attention the r-mode oscillations. Finally we end with discussion of GW detection. In Chapter 2 we describe research into the frequencies of r-mode oscillations. Knowing these frequencies can be useful for guiding and interpreting gravitational wave and electromagnetic observations. The frequencies of slowly rotating, barotropic, and non-magnetic Newtonian stars are well known, but subject to various corrections. After making simple estimates of the relative strengths of these corrections we conclude that relativistic corrections are the most important. For this reason we extend the formalism of K. H. Lockitch, J. L. Friedman, and N. Andersson [Phys. Rev. D 68, 124010 (2003)], who consider relativistic polytropes, to the case of realistic equations of state. This formulation results in perturbation equations which are solved using a spectral method. We find that for realistic equations of state the r-mode frequency ranges from 1.39--1.57 times the spin frequency of the star when the relativistic compactness parameter (M/R) is varied over the astrophysically motivated interval 0.110--0.310. Following a successful r-mode detection our results can help constrain the high density equation of state. In Chapter 3 we present a technical introduction to the data analysis tools used in GW searches. Starting from the plane-wave solutions derived in Chapter 1 we develop the F-statistic used in the matched filtering technique. This technique relies on coherently integrating the GW detector's data stream with a theoretically modeled wave signal. The statistic is used to test the null hypothesis that the data contains no signal. In this chapter we also discuss how to
Polnarev, A. G.; Baskaran, D.
2008-06-15
In the current work we investigate the propagation of electromagnetic waves in the field of gravitational waves. Starting with the simple case of an electromagnetic wave traveling in the field of a plane monochromatic gravitational wave, we introduce the concept of the surfing effect and analyze its physical consequences. We then generalize these results to an arbitrary gravitational wave field. We show that, due to the transverse nature of gravitational waves, the surfing effect leads to significant observable consequences only if the velocity of gravitational waves deviates from the speed of light. This fact can help to place an upper limit on the deviation of gravitational wave velocity from the speed of light. The microarcsecond resolution promised by the upcoming precision interferometry experiments allow one to place stringent upper limits on {epsilon}=(v{sub gw}-c)/c as a function of the energy density parameter for gravitational waves {omega}{sub gw}. For {omega}{sub gw}{approx_equal}10{sup -10} this limit amounts to {epsilon} < or approx. 2{center_dot}10{sup -2}.
Magnetar asteroseismology with long-term gravitational waves
Kashiyama, Kazumi; Ioka, Kunihito
2011-04-15
Magnetic flares and induced oscillations of magnetars (supermagnetized neutron stars) are promising sources of gravitational waves (GWs). We suggest that the GW emission, if any, would last longer than the observed x-ray quasiperiodic oscillations (X-QPOs), calling for longer-term GW analyses lasting a day to months, compared to current searches' durations. Like the pulsar timing, the oscillation frequency would also evolve with time because of the decay or reconfiguration of the magnetic field, which is crucial for the GW detection. With the observed GW frequency and its time-derivatives, we can probe the interior magnetic field strength of {approx}10{sup 16} G and its evolution to open a new GW asteroseismology with the next generation interferometers like the advanced laser interferometer gravitational wave observatory, the advanced Virgo gravitational wave detector at the European Gravitational Observatory, the Large-scale cryogenic gravitational wave telescope, and the Einstein telescope.
NASA Astrophysics Data System (ADS)
Poppeliers, C.; Mallinson, D. J.
2015-12-01
Breaking waves in the near-shore are known to generate a significant amount of high frequency (f>5 Hz) energy. We investigate the correlation between the spectrum of seismic energy and the local sea states. We deployed a single three-component broadband seismometer approximately 50 m from the sea shore and recorded continuously for approximately 10 days. Our observations show that during elevated sea states, and presumably larger breaking waves in the surf zone, the power spectral density of the wave-generated seismic energy shifts to lower frequencies and higher spectral amplitudes. The correlation of the seismic spectral power to the height and period of ocean waves suggests that seismic observations can be used as a proxy for local sea states, which may have implications for sea shore sediment transport.
NASA Astrophysics Data System (ADS)
Dajun, Wang; Chunyan, Zhou; Li, Junbao; Shen, Song; Li, Min; Liu, Xijun
2013-07-01
This paper presents an experimental investigation on nonlinear low frequency gravity water waves in a partially filled cylindrical shell subjected to high frequency horizontal excitations. The characteristics of natural frequencies and mode shapes of the water-shell coupled system are discussed. The boundaries for onset of gravity waves are measured and plotted by curves of critical excitation force magnitude with respect to excitation frequency. For nonlinear water waves, the time history signals and their spectrums of motion on both water surface and shell are recorded. The shapes of water surface are also measured using scanning laser vibrometer. In particular, the phenomenon of transitions between different gravity wave patterns is observed and expressed by the waterfall graphs. These results exhibit pronounced nonlinear properties of shell-fluid coupled system.
Stochastic gravitational wave background from light cosmic strings
DePies, Matthew R.; Hogan, Craig J.
2007-06-15
Spectra of the stochastic gravitational wave backgrounds from cosmic strings are calculated and compared with present and future experimental limits. Motivated by theoretical expectations of light cosmic strings in superstring cosmology, improvements in experimental sensitivity, and recent demonstrations of large, stable loop formation from a primordial network, this study explores a new range of string parameters with masses lighter than previously investigated. A standard 'one-scale' model for string loop formation is assumed. Background spectra are calculated numerically for dimensionless string tensions G{mu}/c{sup 2} between 10{sup -7} and 10{sup -18}, and initial loop sizes as a fraction of the Hubble radius {alpha} from 0.1 to 10{sup -6}. The spectra show a low frequency power-law tail, a broad spectral peak due to loops decaying at the present epoch (including frequencies higher than their fundamental mode, and radiation associated with cusps), and a flat (constant energy density) spectrum at high frequencies due to radiation from loops that decayed during the radiation-dominated era. The string spectrum is distinctive and unlike any other known source. The peak of the spectrum for light strings appears at high frequencies, significantly affecting predicted signals. The spectra of the cosmic string backgrounds are compared with current millisecond pulsar limits and Laser Interferometer Space Antenna (LISA) sensitivity curves. For models with large stable loops ({alpha}=0.1), current pulsar-timing limits exclude G{mu}/c{sup 2}>10{sup -9}, a much tighter limit on string tension than achievable with other techniques, and within the range of current models based on brane inflation. LISA may detect a background from strings as light as G{mu}/c{sup 2}{approx_equal}10{sup -16}, corresponding to field theory strings formed at roughly 10{sup 11} GeV.
Gravitational waves from spinning eccentric binaries
NASA Astrophysics Data System (ADS)
Csizmadia, Péter; Debreczeni, Gergely; Rácz, István; Vasúth, Mátyás
2012-12-01
This paper is to introduce a new software called CBwaves which provides a fast and accurate computational tool to determine the gravitational waveforms yielded by generic spinning binaries of neutron stars and/or black holes on eccentric orbits. This is done within the post-Newtonian (PN) framework by integrating the equations of motion and the spin precession equations, while the radiation field is determined by a simultaneous evaluation of the analytic waveforms. In applying CBwaves various physically interesting scenarios have been investigated. In particular, we have studied the appropriateness of the adiabatic approximation, and justified that the energy balance relation is indeed insensitive to the specific form of the applied radiation reaction term. By studying eccentric binary systems, it is demonstrated that circular template banks are very ineffective in identifying binaries even if they possess tiny residual orbital eccentricity, thus confirming a similar result obtained by Brown and Zimmerman (2010 Phys. Rev. D 81 024007). In addition, by investigating the validity of the energy balance relation we show that, contrary to the general expectations, the PN approximation should not be applied once the PN parameter gets beyond the critical value ˜0.08 - 0.1. Finally, by studying the early phase of the gravitational waves emitted by strongly eccentric binary systems—which could be formed e.g. in various many-body interactions in the galactic halo—we have found that they possess very specific characteristics which may be used to identify these type of binary systems. This paper is dedicated to the memory of our colleague and friend Péter Csizmadia a young physicist, computer expert and one of the best Hungarian mountaineers who disappeared in China’s Sichuan near the Ren Zhong Feng peak of the Himalayas on 23 Oct. 2009. We started to develop CBwaves jointly with Péter a couple of months before he left for China.
NASA Astrophysics Data System (ADS)
Chan, H.; Masserey, B.; Fromme, P.
2015-03-01
Varying loading conditions of aircraft structures result in stress concentration at fastener holes, where multi-layered components are connected, potentially leading to the development of hidden fatigue cracks in inaccessible layers. High frequency guided waves propagating along the structure allow for the structural health monitoring (SHM) of such components, e.g., aircraft wings. Experimentally the required guided wave modes can be easily excited using standard ultrasonic wedge transducers. However, the sensitivity for the detection of small, potentially hidden, fatigue cracks has to be ascertained. The type of multi-layered model structure investigated consists of two adhesively bonded aluminum plate-strips with a sealant layer. Fatigue experiments were carried out and the growth of fatigue cracks at the fastener hole in one of the metallic layers was monitored optically during cyclic loading. The influence of the fatigue cracks of increasing size on the scattered guided wave field was evaluated. The sensitivity and repeatability of the high frequency guided wave modes to detect and monitor the fatigue crack growth was investigated, using both standard pulse-echo equipment and a laser interferometer. The potential for hidden fatigue crack growth monitoring at critical and difficult to access fastener locations from a stand-off distance was ascertained. The robustness of the methodology for practical in situ ultrasonic monitoring of fatigue crack growth is discussed.
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).
Precision Ephemerides for Gravitational Wave Searches. II. Cyg X-2
NASA Astrophysics Data System (ADS)
Premachandra, Sammanani S.; Galloway, Duncan K.; Casares, Jorge; Steeghs, Danny T.; Marsh, Thomas R.
2016-06-01
Accreting neutron stars in low-mass X-ray binaries are candidate high-frequency persistent gravitational wave sources. These may be detectable with next-generation interferometers such as Advanced LIGO/VIRGO within this decade. However, the search sensitivity is expected to be limited principally by the uncertainty in the binary system parameters. We combine new optical spectroscopy of Cyg X-2 obtained with the Liverpool Telescope with available historical radial velocity data, which gives us improved orbital parameter uncertainties based on a 44 year baseline. We obtained an improvement of a factor of 2.6 in the orbital period precision and a factor of 2 in the epoch of inferior conjunction T 0. The updated orbital parameters imply a mass function of 0.65 ± 0.01 M ⊙, leading to a primary mass (M 1) of 1.67 ± 0.22 M ⊙ (for i = 62.{}^\\circ 5+/- 4^\\circ ). In addition, we estimate the likely orbital parameter precision through to the expected Advanced LIGO and VIRGO detector observing period and quantify the corresponding improvement in sensitivity via the required number of templates.
Design of readout IC for photoelectron detector of short-wave high frequency IRFPA
NASA Astrophysics Data System (ADS)
Wang, Pan; Ding, Rui-jun; Chen, Guo-qiang; Chen, Honglei
2013-01-01
Design of readout-integrated circuit(ROIC) with high frequency and low signal for 512×256 short wavelength(SW) inferred-focal-plane-arrays(IRFPAs) is presented. The ROIC with high performance in frame rate can integrate and read out the low signal. An analog signal chain, which contains CTIA, CDS module, amplifier of charge and complementary output stage, can satisfy the high frequency and low signal application. A reliable digital control structure of IRFPA ROIC is presented, with which the integral voltage of arbitrary contiguous or noncontiguous lines, rather than regular lines, can be selected to readout. The simulation and verification are completed both before and after completing the layout. The circuit's structure and operation principle are analyzed under the environment of mix-signal, and the result shows that the output dynamic range is over 2.5V, the charge capacity is more than 1Me-, the frame rate is 250Hz, the linearity within useful dynamic range is above 99.9 percent.
Improving Horizontal Resolution of High-frequency Surface-wave Methods Using Travel-time Tomography
NASA Astrophysics Data System (ADS)
Yin, X.; Xia, J.; Sun, S.; Shen, C.
2015-12-01
In surface-wave methods, horizontal resolution can be defined as the ability to distinguish anomalous objects that are laterally displaced from each other. And the horizontal length of a recognizable geological anomalous body is measured by the lateral variation of S-wave velocity. Multichannel analysis of surface waves (MASW) method is an efficient tool to determine near-surface shear-wave velocities. The acquisition of the MASW method involves the same source-receiver configuration moved successively by a fixed distance interval (a few to several stations) along a linear survey line, which is called a roll-along acquisition geometry. A pseudo-2D S-wave velocity section is constructed by aligning 1D models, and each inverted 1D S-wave velocity model reflects the vertical S-wave velocity variation at the midpoint of each geophone spread. Although the MASW method can improve the horizontal resolution of S-wave velocity sections to some degree, the amount of fieldwork is increased by the roll-along acquisition geometry. We propose surface-wave tomography method to investigate horizontal resolution of surface-wave exploration. Phase-velocity dispersion curves are calculated by a pair of traces within a multichannel record through cross-correlation combined with a phase-shift scanning method. Then with the utilization of travel-time tomography, we can obtain high resolution pure-path dispersion curves with diverse sizes of grids at different frequencies. Finally, the pseudo-2D S-wave velocity structure is reconstructed by inverting the pure-path dispersion curves. Travel-time tomography of surface waves can extract accurate dispersion curves from a record with a short receiver spacing, and it can effectively enhance the ability of random noise immunity. Synthetic tests and a real-world example have indicated that travel-time tomography has a great potential for improving the horizontal resolution of surface waves. Keywords: Travel-time tomography of surface waves
Composite gravitational-wave detection of compact binary coalescence
Cannon, Kipp; Hanna, Chad; Keppel, Drew; Searle, Antony C.
2011-04-15
The detection of gravitational waves from compact binaries relies on a computationally burdensome processing of gravitational-wave detector data. The parameter space of compact-binary-coalescence gravitational waves is large and optimal detection strategies often require nearly redundant calculations. Previously, it has been shown that singular value decomposition of search filters removes redundancy. Here we will demonstrate the use of singular value decomposition for a composite detection statistic. This can greatly improve the prospects for a computationally feasible rapid detection scheme across a large compact binary parameter space.
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%. PMID:21532671
Observable induced gravitational waves from an early matter phase
Alabidi, Laila; Sasaki, Misao; Kohri, Kazunori; Sendouda, Yuuiti E-mail: kohri@post.kek.jp E-mail: sendouda@cc.hirosaki-u.ac.jp
2013-05-01
Assuming that inflation is succeeded by a phase of matter domination, which corresponds to a low temperature of reheating T{sub r} < 10{sup 9}GeV, we evaluate the spectra of gravitational waves induced in the post-inflationary universe. We work with models of hilltop-inflation with an enhanced primordial scalar spectrum on small scales, which can potentially lead to the formation of primordial black holes. We find that a lower reheat temperature leads to the production of gravitational waves with energy densities within the ranges of both space and earth based gravitational wave detectors.
Gravitational waves from kinks on infinite cosmic strings
Kawasaki, Masahiro; Miyamoto, Koichi; Nakayama, Kazunori
2010-05-15
Gravitational waves emitted by kinks on infinite strings are investigated using detailed estimations of the kink distribution on infinite strings. We find that gravitational waves from kinks can be detected by future pulsar timing experiments such as SKA for an appropriate value of the string tension, if the typical size of string loops is much smaller than the horizon at their formation. Moreover, the gravitational wave spectrum depends on the thermal history of the Universe and hence it can be used as a probe into the early evolution of the Universe.
Three-point statistics of cosmological stochastic gravitational waves
Adshead, Peter; Lim, Eugene A.
2010-07-15
We consider the three-point function (i.e. the bispectrum or non-Gaussianity) for stochastic backgrounds of gravitational waves. We estimate the amplitude of this signal for the primordial inflationary background, gravitational waves generated during preheating, and for gravitational waves produced by self-ordering scalar fields following a global phase transition. To assess detectability, we describe how to extract the three-point signal from an idealized interferometric experiment and compute the signal to noise ratio as a function of integration time. The three-point signal for the stochastic gravitational wave background generated by inflation is unsurprisingly tiny. For gravitational radiation generated by purely causal, classical mechanisms we find that, no matter how nonlinear the process is, the three-point correlations produced vanish in direct detection experiments. On the other hand, we show that in scenarios where the B-mode of the cosmic microwave background is sourced by gravitational waves generated by a global phase transition, a strong three-point signal among the polarization modes is also produced. This may provide another method of distinguishing inflationary B-modes. To carry out this computation, we have developed a diagrammatic approach to the calculation of stochastic gravitational waves sourced by scalar fluids, which has applications beyond the present scenario.
Analysis of group-velocity dispersion of high-frequency Rayleigh waves for near-surface applications
Luo, Y.; Xia, J.; Xu, Y.; Zeng, C.
2011-01-01
The Multichannel Analysis of Surface Waves (MASW) method is an efficient tool to obtain the vertical shear (S)-wave velocity profile using the dispersive characteristic of Rayleigh waves. Most MASW researchers mainly apply Rayleigh-wave phase-velocity dispersion for S-wave velocity estimation with a few exceptions applying Rayleigh-wave group-velocity dispersion. Herein, we first compare sensitivities of fundamental surface-wave phase velocities with group velocities with three four-layer models including a low-velocity layer or a high-velocity layer. Then synthetic data are simulated by a finite difference method. Images of group-velocity dispersive energy of the synthetic data are generated using the Multiple Filter Analysis (MFA) method. Finally we invert a high-frequency surface-wave group-velocity dispersion curve of a real-world example. Results demonstrate that (1) the sensitivities of group velocities are higher than those of phase velocities and usable frequency ranges are wider than that of phase velocities, which is very helpful in improving inversion stability because for a stable inversion system, small changes in phase velocities do not result in a large fluctuation in inverted S-wave velocities; (2) group-velocity dispersive energy can be measured using single-trace data if Rayleigh-wave fundamental-mode energy is dominant, which suggests that the number of shots required in data acquisition can be dramatically reduced and the horizontal resolution can be greatly improved using analysis of group-velocity dispersion; and (3) the suspension logging results of the real-world example demonstrate that inversion of group velocities generated by the MFA method can successfully estimate near-surface S-wave velocities. ?? 2011 Elsevier B.V.
Siemens, M.; Li, Q.; Murnane, M.; Kapteyn, H.; Yang, R.; Anderson, E.; Nelson, K.
2009-03-02
We study ultrahigh frequency surface acoustic wave propagation in nickel-on-sapphire nanostructures. The use of ultrafast, coherent, extreme ultraviolet beams allows us to extend optical measurements of propagation dynamics of surface acoustic waves to frequencies of nearly 50 GHz, corresponding to wavelengths as short as 125 nm. We repeat the measurement on a sequence of nanostructured samples to observe surface acoustic wave dispersion in a nanostructure series for the first time. These measurements are critical for accurate characterization of thin films using this technique.
High-frequency sound waves to eliminate a horizon in the mixmaster universe.
NASA Technical Reports Server (NTRS)
Chitre, D. M.
1972-01-01
From the linear wave equation for small-amplitude sound waves in a curved space-time, there is derived a geodesiclike differential equation for sound rays to describe the motion of wave packets. These equations are applied in the generic, nonrotating, homogeneous closed-model universe (the 'mixmaster universe,' Bianchi type IX). As for light rays described by Doroshkevich and Novikov (DN), these sound rays can circumnavigate the universe near the singularity to remove particle horizons only for a small class of these models and in special directions. Although these results parallel those of DN, different Hamiltonian methods are used for treating the Einstein equations.
Servant, G; Caltagirone, J P; Gérard, A; Laborde, J L; Hita, A
2000-10-01
The use of high frequency ultrasound in chemical systems is of major interest to optimize chemical procedures. Characterization of an open air 477 kHz ultrasound reactor shows that, because of the collapse of transient cavitation bubbles and pulsation of stable cavitation bubbles, chemical reactions are enhanced. Numerical modelling is undertaken to determine the spatio-temporal evolution of cavitation bubbles. The calculus of the emergence of cavitation bubbles due to the acoustic driving (by taking into account interactions between the sound field and bubbles' distribution) gives a cartography of bubbles' emergence within the reactor. Computation of their motion induced by the pressure gradients occurring in the reactor show that they migrate to the pressure nodes. Computed bubbles levitation sites gives a cartography of the chemical activity of ultrasound. Modelling of stable cavitation bubbles' motion induced by the motion of the liquid gives some insight on degassing phenomena. PMID:11062879
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.
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.
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.
Gravitational wave damping of neutron star wobble
NASA Astrophysics Data System (ADS)
Cutler, Curt; Jones, David Ian
2001-01-01
We calculate the effect of gravitational wave (GW) back reaction on realistic neutron stars (NS's) undergoing torque-free precession. By ``realistic'' we mean that the NS is treated as a mostly fluid body with an elastic crust, as opposed to a rigid body. We find that GW's damp NS wobble on a time scale τθ~2×105 yr [10- 7/(ΔId/I0)]2(kHz/ νs)4, where νs is the spin frequency and ΔId is the piece of the NS's inertia tensor that ``follows'' the crust's principal axis (as opposed to its spin axis). We give two different derivations of this result: one based solely on energy and angular momentum balance, and another obtained by adding the Burke-Thorne radiation reaction force to the Newtonian equations of motion. This problem was treated long ago by Bertotti and Anile, but their claimed result is wrong. When we convert from their notation to ours, we find that their τθ is too short by a factor of ~105 for the typical cases of interest and even has the wrong sign for ΔId negative. We show where their calculation went astray.
Measuring the speed of cosmological gravitational waves
NASA Astrophysics Data System (ADS)
Raveri, Marco; Baccigalupi, Carlo; Silvestri, Alessandra; Zhou, Shuang-Yong
2015-03-01
In general relativity gravitational waves propagate at the speed of light; however, in alternative theories of gravity that might not be the case. We investigate the effects of a modified speed of gravity, cT2, on the B modes of the cosmic microwave background (CMB) anisotropy in polarization. We find that a departure from the light speed value would leave a characteristic imprint on the BB spectrum part induced by tensors, manifesting as a shift in the angular scale of its peaks which allows us to constrain cT without any significant degeneracy with other cosmological parameters. We derive constraints from current data and forecast the accuracy with which cT will be measured by the next generation CMB satellites. In the former case, using the available Planck and BICEP2 data sets, we obtain cT2=1.30 ±0.79 and cT2<2.85 at 95% C.L. by assuming a power law primordial tensor power spectrum and cT2<2.33 at 95% C.L. if the running of the spectral index is allowed. More interestingly, in the latter case we find future CMB satellites capable of constraining cT2 at percent level, comparable with bounds from binary pulsar measurements, largely due to the absence of degeneracy with other cosmological parameters.
NASA's Gravitational-Wave Mission Concept Study
NASA Astrophysics Data System (ADS)
Stebbins, Robin; Jennrich, Oliver; McNamara, Paul
2012-07-01
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 key performance parameters, assess risk and estimate cost and schedule. The Study results are summarized.
Attenuation of high-frequency body waves in the crust of the Central External Dinarides
NASA Astrophysics Data System (ADS)
Dasović, Iva; Ruščić, Marija; Herak, Davorka; Herak, Marijan
2015-10-01
The Central External Dinarides are known as a tectonically complex region of moderate seismicity where several strong earthquakes occurred in the last century. In order to gain insight into the attenuation of seismic waves in the area, the extended coda normalization method was applied to band-pass-filtered seismograms of local earthquakes recorded at seven seismological broadband stations. Obtained results indicate strong attenuation of direct body waves: Q 0,P = Q P(1 Hz) is found between 21 and 120 and Q 0,S = Q S(1 Hz) is between 46 and 113, whereas the exponent n in the power law of frequency dependence of the quality factor is found in the range of 0.63-1.52 and 0.65-0.97 for n P and n S, respectively. P-waves are, on the average, attenuated more than S-waves. The three island stations (Dugi Otok (DUGI), Žirje (ZIRJ), Hvar (HVAR)) are distinguished by the strong low-frequency P-wave attenuation and more pronounced frequency dependence of the Q P factor ( Q 0,S/ Q 0,P > 1.7, Q 0,P < 60, n P > n S). The remaining four inland stations (Udbina (UDBI), Morići (MORI), Kijevo (KIJV), Čačvina (CACV)) all exhibit similar qualitative attenuation properties for P- and S-waves ( n P ≈ n S ≈ 1 and Q 0,S ≈ Q 0,P), although individual values of the Q-factors vary notably within this group. Low-frequency attenuation of direct S-waves in the crust is stronger than mean attenuation of scattered coda waves in the lithosphere, especially for long coda lapse times. The results are also qualitatively in agreement with the thermal regime in the area.
Estimating gravity wave parameters from oblique high-frequency backscatter: Modeling and analysis
Bristow, W.A.; Greenwald, R.A.
1995-03-01
A new technique for estimating electron density perturbation amplitudes of traveling ionospheric disturbances (TIDs), using HF radar data, is presented. TIDs are observed in HF radar data as enhancements of the ground-scattered power which propagate through the radar`s field of view. These TIDs are the ionospheric manifestation of atmospheric acoustic-gravity waves. TID electron density perturbation amplitudes were estimated by simulating the radar returns, using HF ray tracing through a model ionosphere perturbed by a model gravity wave. The simulation determined the return power in the ground-scattered portion of the signal as a function of range, and this was compared to HF radar data from the Goose Bay HF radar at a time when evidence of gravity waves was present in the data. By varying the amplitude of the electron density perturbation in the model it was possible to estimate the perturbation of the actual wave. It was found that the perturbations that are observed by the Goose Bay HF radar are of the order of 20% to 35%. It was also found that the number of observable power enhancements, and the relative amplitudes of these enhancements, depended on the vertical thickness of the gravity wave`s source region. From the simulations and observations it was estimated that the source region for the case presented here was approximately 20 km thick. In addition, the energy in the wave packet was calculated and compared to an estimate of the available energy in the source region. It was found that the wave energy was about 0.2% of the estimated available source region energy. 20 refs., 12 figs.
Gravitational wave astrophysics, data analysis and multimessenger astronomy
NASA Astrophysics Data System (ADS)
Lee, Hyung Mok; Le Bigot, Eric-Olivier; Du, ZhiHui; Lin, ZhangXi; Guo, XiangYu; Wen, LinQing; Phukon, Khun Sang; Pandey, Vihan; Bose, Sukanta; Fan, Xi-Long; Hendry, Martin
2015-12-01
This paper reviews gravitational wave sources and their detection. One of the most exciting potential sources of gravitational waves are coalescing binary black hole systems. They can occur on all mass scales and be formed in numerous ways, many of which are not understood. They are generally invisible in electromagnetic waves, and they provide opportunities for deep investigation of Einstein's general theory of relativity. Sect. 1 of this paper considers ways that binary black holes can be created in the universe, and includes the prediction that binary black hole coalescence events are likely to be the first gravitational wave sources to be detected. The next parts of this paper address the detection of chirp waveforms from coalescence events in noisy data. Such analysis is computationally intensive. Sect. 2 reviews a new and powerful method of signal detection based on the GPUimplemented summed parallel infinite impulse response filters. Such filters are intrinsically real time alorithms, that can be used to rapidly detect and localise signals. Sect. 3 of the paper reviews the use of GPU processors for rapid searching for gravitational wave bursts that can arise from black hole births and coalescences. In sect. 4 the use of GPU processors to enable fast efficient statistical significance testing of gravitational wave event candidates is reviewed. Sect. 5 of this paper addresses the method of multimessenger astronomy where the discovery of electromagnetic counterparts of gravitational wave events can be used to identify sources, understand their nature and obtain much greater science outcomes from each identified event.
Enabling high confidence detections of gravitational-wave bursts
NASA Astrophysics Data System (ADS)
Littenberg, Tyson B.; Kanner, Jonah B.; Cornish, Neil J.; Millhouse, Margaret
2016-08-01
Extracting astrophysical information from gravitational-wave detections is a well-posed problem and thoroughly studied when detailed models for the waveforms are available. However, one motivation for the field of gravitational-wave astronomy is the potential for new discoveries. Recognizing and characterizing unanticipated signals requires data analysis techniques which do not depend on theoretical predictions for the gravitational waveform. Past searches for short-duration unmodeled gravitational-wave signals have been hampered by transient noise artifacts, or "glitches," in the detectors. We have put forth the BayesWave algorithm to differentiate between generic gravitational-wave transients and glitches, and to provide robust waveform reconstruction and characterization of the astrophysical signals. Here we study BayesWave's capabilities for rejecting glitches while assigning high confidence to detection candidates through analytic approximations to the Bayesian evidence. Analytic results are tested with numerical experiments by adding simulated gravitational-wave transient signals to LIGO data collected between 2009 and 2010 and found to be in good agreement.
Origins of high-frequency scattered waves near PKKP from large aperture seismic array data
Earle, P.S.
2002-01-01
This article identifies the likely origin of 1-Hz scattered waves in the vicinity of PKKP by comparing measurements of slowness and onset time to ray-theoretical predictions. The measurements are obtained from slant stacks of Large Aperture Seismic Array (LASA) data from 36 earthquakes and six explosions in the range 30??-116??. Three types of scattered waves explain the main features seen in the stacks, including: P scattered to PKP near the Earth's surface (P.PKP), PKKP scattered near its core-mantle-boundary (CMB) reflection point (PK.KP), and SKKP scattered near its CMB reflection point (SK.KP). The LASA stacks image the amplitude and slowness variations of the scattered waves with time. They also show where these waves can be detected and where they are free from contaminating arrivals. SK.KP waves rise above the noise approximately 100 sec before the onset time of the main SKKP arrival near 113??. Observations of PK.KP span 30??-100??. However, at distances greater than 50?? they suffer from P.PKP contamination. At distances less than 40?? the PK.KP last for about 280 sec. This is approximately 130 sec longer than the maximum ray-theoretical prediction for waves scattered at the CMB, indicating a possible combination of near-surface scattering and contributions from the overlying mantle.
Aseeva, N. V. Gromov, E. M.; Tyutin, V. V.
2015-12-15
The dynamics of high-frequency field solitons is considered using the extended nonhomogeneous nonlinear Schrödinger equation with induced scattering from damped low-frequency waves (pseudoinduced scattering). This scattering is a 3D analog of the stimulated Raman scattering from temporal spatially homogeneous damped low-frequency modes, which is well known in optics. Spatial inhomogeneities of secondorder linear dispersion and cubic nonlinearity are also taken into account. It is shown that the shift in the 3D spectrum of soliton wavenumbers toward the short-wavelength region is due to nonlinearity increasing in coordinate and to decreasing dispersion. Analytic results are confirmed by numerical calculations.
Electromagnetic Resonance of Astigmatic Gaussian Beam to the High Frequency Gravitational Waves
NASA Astrophysics Data System (ADS)
Zhong, Yuan-Hong; Li, Jin; Zhou, Yao; Lei, Qi-Lun
2016-10-01
Not Available Supported by the National Natural Science Foundation of China under Grant Nos 11205254 and 61501069, and the Fundamental Research Funds for the Central Universities under Grant No 106112016CDJXY300002.
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.
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...
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.
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.
Thermal Noise in Laser Interferometer Gravitational Wave Detectors
NASA Astrophysics Data System (ADS)
Flaminio, Raffaele
Thermal noise is one of the major limitations to the sensitivity of present and future laser interferometers devoted to gravitational wave detection. According to the fluctuation-dissipation theorem any mechanical oscillator is affected by a motion of thermal origin directly related to its thermodynamic temperature. The mirrors and their suspensions that are used in gravitational wave detectors such as Virgo or LIGO are examples of such mechanical oscillators. As a consequence their position is affected by this thermal vibration and the sensitivity of the gravitational wave detector is thermal noise limited over a wide range of frequencies. After recalling briefly the fluctuation-dissipation theorem and its origins, this chapter describes the main types of thermal noise affecting gravitational wave detectors. In the last part of the chapter a special emphasis is given to the thermal noise due to dissipation in the mirrors optical coatings.
Black Hole Kicks as New Gravitational Wave Observables
NASA Astrophysics Data System (ADS)
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.
PREFACE: 8th Edoardo Amaldi Conference on Gravitational Waves
NASA Astrophysics Data System (ADS)
Marka, Zsuzsa; Marka, Szabolcs
2010-04-01
(The attached PDF contains select pictures from the Amaldi8 Conference) At Amaldi7 in Sydney in 2007 the Gravitational Wave International Committee (GWIC), which oversees the Amaldi meetings, decided to hold the 8th Edoardo Amaldi Conference on Gravitational Waves at Columbia University in the City of New York. With this decision, Amaldi returned to North America after a decade. The previous two years have seen many advances in the field of gravitational wave detection. By the summer of 2009 the km-scale ground based interferometric detectors in the US and Europe were preparing for a second long-term scientific run as a worldwide detector network. The advanced or second generation detectors had well-developed plans and were ready for the production phase or started construction. The European-American space mission, LISA Pathfinder, was progressing towards deployment in the foreseeable future and it is expected to pave the ground towards gravitational wave detection in the milliHertz regime with LISA. Plans were developed for an additional gravitational wave detector in Australia and in Japan (in this case underground) to extend the worldwide network of detectors for the advanced detector era. Japanese colleagues also presented plans for a space mission, DECIGO, that would bridge the gap between the LISA and ground-based interferometer frequency range. Compared to previous Amaldi meetings, Amaldi8 had new elements representing emerging trends in the field. For example, with the inclusion of pulsar timing collaborations to the GWIC, gravitational wave detection using pulsar timing arrays was recognized as one of the prominent directions in the field and was represented at Amaldi8 as a separate session. By 2009, searches for gravitational waves based on external triggers received from electromagnetic observations were already producing significant scientific results and plans existed for pointing telescopes by utilizing gravitational wave trigger events. Such
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. PMID:27419556
Gravitational Waves from Magnetized Binary Neutron Star Mergers
NASA Astrophysics Data System (ADS)
Giacomazzo, Bruno; Rezzolla, Luciano; Baiotti, Luca
2010-02-01
Binary neutron stars are among the most important sources of gravitational waves which are expected to be detected by the current or next generation of gravitational wave detectors, such as LIGO and Virgo, and they are also thought to be at the origin of very important astrophysical phenomena, such as short gamma-ray bursts. In order to describe the dynamics of these events one needs to solve the full set of general relativistic magnetohydrodynamics equations through the use of parallel numerical codes. I will report on some recent results obtained with the use of the fully general relativistic magnetohydrodynamic code Whisky in simulating binary neutron stars which inspiral and merge forming an hypermassive neutron star which eventually collapses to form a black hole surrounded by a torus. I will in particular describe how the magnetic fields can affect the dynamics and consequently the gravitational waves emitted by these systems and discuss about their detectability by current and future gravitational-wave detectors. )
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.
Finite beta effects on low- and high-frequency magnetosonic waves in a two-ion-species plasma
Toida, Mieko; Aota, Yukio
2013-08-15
A magnetosonic wave propagating perpendicular to a magnetic field in a two-ion-species plasma has two branches, high-frequency and low-frequency modes. The finite beta effects on these modes are analyzed theoretically on the basis of the three-fluid model with finite ion and electron pressures. First, it is shown that the Korteweg-de Vries (KdV) equation for the low-frequency mode is valid for amplitudes ε<ε{sub max}, where the upper limit of the amplitude ε{sub max} is given as a function of β (β is the ratio of the kinetic and magnetic energy densities), the density ratio, and the cyclotron frequency ratio of two ion species. Next, the linear dispersion relation and KdV equation for the high-frequency mode are derived, including β as a factor. In addition, the theory for heavy ion acceleration by the high-frequency mode pulse and the pulse damping due to this energy transfer in a finite beta plasma are presented.
Estimating gravity wave parameters from oblique high-frequency backscatter: Modeling and analysis
NASA Technical Reports Server (NTRS)
Bristow, W. A.; Greenwald, R. A.
1995-01-01
A new technique for estimating electron density perturbation amplitudes of traveling ionospheric disturbances (TIDs), using HF radar data, is presented. TIDs are observed in HF radar data as enhancements of the ground-scattered power which propagate through the radar's field of view. These TIDs are the ionospheric manifestation of atmospheric acoustic-gravity waves. TID electron density perturbation amplitudes were estimated by simulating the radar returns, using HF ray tracing through a model ionosphere perturbed by a model gravity wave. The simulation determined the return power in the ground-scattered portion of the signal as a function of range, and this was compared to HF radar data from the Goose Bay HF radar at a time when evidence of gravity waves was present in the data. By varying the amplitude of the electron density perturbation in the model it was possible to estimate the perturbation of the actual wave. It was found that the perturbations that are observed by the Goose Bay HF radar are of the order of 20% to 35%. It was also found that the number of observable power enhancements, and the relative amplitudes of these enhancements, depended on the vertical thickness of the gravity wave's source region. From the simulations and observations it was estimated that the source region for the case presented here was approximately 20 km thick. In addition, the energy in the wave packet was calculated and compared to an estimate of the available energy in the source region. It was found that the wave energy was about 0.2% of the estimated available source region energy.
Intensity statistics of very high frequency sound scattered from wind-driven waves.
Walstead, Sean P; Deane, Grant B
2016-05-01
The interaction of vhf 100-1000 kHz underwater sound with the ocean surface is explored. The bistatic forward scatter of 300 kHz sound is measured in a wind driven wave channel. Fluctuations in arrival amplitude are described by the scintillation index (SI) which is a measure of arrival intensity variance. SI initially increases with wind speed but eventually saturates to a value of 0.5 when the root-mean-square (rms) roughness is 0.5 mm. An adjusted scintillation index (SI*) is suggested that accounts for the multiple arrivals and properly saturates to a value of 1. Fluctuations in arrival time do not saturate and increase proportionately to the dominant surface wave component. Forward scattering is modeled at frequencies ranging from 50 to 2000 kHz using the Helmholtz-Kirchhoff integral with surface wave realizations derived from wave gauge data. The amplitude and temporal statistics of the simulated scattering agree well with measured data. Intensity saturation occurs at lower wind speeds for higher frequency sound. Both measured and modeled vhf sound is characterized by many surface arrivals at saturation. Doppler shifts associated with wave motion are expected to vary rapidly for vhf sound however further analysis is required.
Intensity statistics of very high frequency sound scattered from wind-driven waves.
Walstead, Sean P; Deane, Grant B
2016-05-01
The interaction of vhf 100-1000 kHz underwater sound with the ocean surface is explored. The bistatic forward scatter of 300 kHz sound is measured in a wind driven wave channel. Fluctuations in arrival amplitude are described by the scintillation index (SI) which is a measure of arrival intensity variance. SI initially increases with wind speed but eventually saturates to a value of 0.5 when the root-mean-square (rms) roughness is 0.5 mm. An adjusted scintillation index (SI*) is suggested that accounts for the multiple arrivals and properly saturates to a value of 1. Fluctuations in arrival time do not saturate and increase proportionately to the dominant surface wave component. Forward scattering is modeled at frequencies ranging from 50 to 2000 kHz using the Helmholtz-Kirchhoff integral with surface wave realizations derived from wave gauge data. The amplitude and temporal statistics of the simulated scattering agree well with measured data. Intensity saturation occurs at lower wind speeds for higher frequency sound. Both measured and modeled vhf sound is characterized by many surface arrivals at saturation. Doppler shifts associated with wave motion are expected to vary rapidly for vhf sound however further analysis is required. PMID:27250171
NASA Astrophysics Data System (ADS)
Murphy, J. R.; Martin, T. Z.; Blackmon, M.; Nelli, S.
2001-11-01
Stationary and high frequency travelling atmospheric thermal waves on Mars have been quantitatively studied via analyses of temperatures obtained with the Mars Global Surveyor orbiter Horizon Sensor Array (MHSA) instrument. This infrared instrument obtains both in-track and cross-track determinations of martian atmospheric temperature with a vertically broad weighting function. The six local times of coverage provided by these four simultaneous fields of view from MGS's sun-synchronous mapping orbit allow for quantification of eastward and westward travelling diurnal and semi-diurnal atmospheric thermal waves. These high frequency wave (tide) phenomena exhibit seasonal variations due to both changing solar heating and to varying atmospheric dust content. Comparisons with numerical model results illustrate the viability of the MHSA time/space sampling to provide valid determination of the amplitudes and phases of these wave phenomena. The results from these studies are complimentary to the more vertically resolved but less time-of-sol abundant MGS TES temperatures. Results of the MHSA analyses indicate the annual persistence of eastward travelling (asynchronous or 'non-travelling') atmospheric tidal modes, and the sensitivity of tidal amplitudes to both season and dust load. Stationary waves at middle latitudes of both hemispheres exhibit significant seasonal variability, as has previously been inferred from TES data and which is theoretically consistent with thermal wind considerations. The accumulating data being obtained by MGS' instruments, including the MHSA, offer the opportunity to investigate interannual atmospheric variability from a self-consistent set of orbital measurements. Current results will be presented. This work has been funded by NASA's Mars Data Analysis Program.
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.
Alternative derivation of the response of interferometric gravitational wave detectors
Cornish, Neil J.
2009-10-15
It has recently been pointed out by Finn that the long-standing derivation of the response of an interferometric gravitational wave detector contains several errors. Here I point out that a contemporaneous derivation of the gravitational wave response for spacecraft doppler tracking and pulsar timing avoids these pitfalls, and when adapted to describe interferometers, recovers a simplified version of Finn's derivation. This simplified derivation may be useful for pedagogical purposes.
Gravitational waves from global second order phase transitions
Jr, John T. Giblin; Price, Larry R.; Siemens, Xavier; Vlcek, Brian E-mail: larryp@caltech.edu E-mail: bvlcek@uwm.edu
2012-11-01
Global second-order phase transitions are expected to produce scale-invariant gravitational wave spectra. In this manuscript we explore the dynamics of a symmetry-breaking phase transition using lattice simulations. We explicitly calculate the stochastic gravitational wave background produced during the transition and subsequent self-ordering phase. We comment on this signal as it compares to the scale-invariant spectrum produced during inflation.
Anisotropies in the gravitational-wave stochastic background
Ölmez, S.; Mandic, V.; Siemens, X. E-mail: mandic@physics.umn.edu
2012-07-01
We consider anisotropies in the stochastic background of gravitational-waves (SBGW) arising from random fluctuations in the number of gravitational-wave sources. We first develop the general formalism which can be applied to different cosmological or astrophysical scenarios. We then apply this formalism to calculate the anisotropies of SBGW associated with the fluctuations in the number of cosmic string loops, considering both cosmic string cusps and kinks. We calculate the anisotropies as a function of angle and frequency.
Inflationary gravitational waves and the evolution of the early universe
Jinno, Ryusuke; Moroi, Takeo; Nakayama, Kazunori E-mail: moroi@hep-th.phys.s.u-tokyo.ac.jp
2014-01-01
We study the effects of various phenomena which may have happened in the early universe on the spectrum of inflationary gravitational waves. The phenomena include phase transitions, entropy productions from non-relativistic matter, the production of dark radiation, and decoupling of dark matter/radiation from thermal bath. These events can create several characteristic signatures in the inflationary gravitational wave spectrum, which may be direct probes of the history of the early universe and the nature of high-energy physics.
Gravitational Wave Science: Challenges for Numerical Relativistic Astrophysics
NASA Technical Reports Server (NTRS)
Cenrella, Joan
2005-01-01
Gravitational wave detectors on earth and in space will open up a new observational window on the universe. The new information about astrophysics and fundamental physics these observations will bring is expected to pose exciting challenges. This talk will provide an overview of this emerging area of gravitational wave science, with a focus on the challenges it will bring for numerical relativistic astrophysics and a look at some recent results.
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. PMID:20868089
Self-focusing of intense high frequency electromagnetic waves in a collisional magnetoactive plasma
Niknam, A. R.; Hashemzadeh, M.; Aliakbari, A.; Majedi, S.; Haji Mirzaei, F.
2011-11-15
The self-focusing of an intense electromagnetic beam in a collisional magnetoactive plasma has been investigated by the perturbation method. Considering the relativistic and ponderomotive nonlinearities and the first three terms of perturbation expansion for the electron density and velocity, the nonlinear wave equation is obtained. This wave equation is solved by applying the source dependent expansion method and the evolution of electromagnetic beam spot-size is discussed. It is shown that the laser spot-size decreases with increasing the collision frequency and external magnetic field strength.
NASA Astrophysics Data System (ADS)
Fernandes, Maria; Alonso-Martirena, Andrés; Agostinho, Pedro; Sanchez, Jorge; Ferrer, Macu; Fernandes, Carlos
2015-04-01
The coastal zone is an important area for the development of maritime countries, either in terms of recreation, energy exploitation, weather forecasting or national security. Field measurements are in the basis of understanding how coastal and oceanic processes occur. Most processes occur over long timescales and over large spatial ranges, like the variation of mean sea level. These processes also involve a variety of factors such as waves, winds, tides, storm surges, currents, etc., that cause huge interference on such phenomena. Measurement of waves have been carried out using different techniques. The instruments used to measure wave parameters can be very different, i.e. buoys, ship base equipment like sonar and satellites. Each equipment has its own advantage and disadvantage depending on the study subject. The purpose of this study is to evaluate the behaviour of a different technology available and presently adopted in wave measurement. In the past few years the measurement of waves using High Frequency (HF) Radars has had several developments. Such a method is already established as a powerful tool for measuring the pattern of surface current, but its use in wave measurements, especially in the dual arrangement is recent. Measurement of the backscatter of HF radar wave provides the raw dataset which is analyzed to give directional data of surface elevation at each range cell. Buoys and radars have advantages, disadvantages and its accuracy is discussed in this presentation. A major advantage with HF radar systems is that they are unaffected by weather, clouds or changing ocean conditions. The HF radar system is a very useful tool for the measurement of waves over a wide area with real-time observation, but it still lacks a method to check its accuracy. The primary goal of this study was to show how the HF radar system responds to high energetic variations when compared to wave buoy data. The bulk wave parameters used (significant wave height, period and
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.
Propagation effect of gravitational wave on detector response
NASA Astrophysics Data System (ADS)
Chang, Zhe; Huang, Chao-Guang; Zhao, Zhi-Chao
2016-10-01
The response of a detector to gravitational wave is a function of frequency. When the time a photon moving around in the Fabry-Perot cavities is the same order of the period of a gravitational wave, the phase-difference due to the gravitational wave should be an integral along the path. We present a formula description for detector response to gravitational wave with varied frequencies. The LIGO data for GW150914 and GW 151226 are reexamined in this framework. For GW150924, the traveling time of a photon in the LIGO detector is just a bit larger than a half period of the highest frequency of gravitational wave and the similar result is obtained with LIGO and Virgo collaborations. However, we are not always so luck. In the case of GW151226, the time of a photon traveling in the detector is larger than the period of the highest frequency of gravitational wave and the announced signal cannot match well the template with the initial black hole masses 14.2M$_\\odot$ and 7.5M$_\\odot$.
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.
Luo, Y.; Xia, J.; Xu, Y.; Zeng, C.; Liu, J.
2010-01-01
Love-wave propagation has been a topic of interest to crustal, earthquake, and engineering seismologists for many years because it is independent of Poisson's ratio and more sensitive to shear (S)-wave velocity changes and layer thickness changes than are Rayleigh waves. It is well known that Love-wave generation requires the existence of a low S-wave velocity layer in a multilayered earth model. In order to study numerically the propagation of Love waves in a layered earth model and dispersion characteristics for near-surface applications, we simulate high-frequency (>5 Hz) Love waves by the staggered-grid finite-difference (FD) method. The air-earth boundary (the shear stress above the free surface) is treated using the stress-imaging technique. We use a two-layer model to demonstrate the accuracy of the staggered-grid modeling scheme. We also simulate four-layer models including a low-velocity layer (LVL) or a high-velocity layer (HVL) to analyze dispersive energy characteristics for near-surface applications. Results demonstrate that: (1) the staggered-grid FD code and stress-imaging technique are suitable for treating the free-surface boundary conditions for Love-wave modeling, (2) Love-wave inversion should be treated with extra care when a LVL exists because of a lack of LVL information in dispersions aggravating uncertainties in the inversion procedure, and (3) energy of high modes in a low-frequency range is very weak, so that it is difficult to estimate the cutoff frequency accurately, and "mode-crossing" occurs between the second higher and third higher modes when a HVL exists. ?? 2010 Birkh??user / Springer Basel AG.
Anatomy of the high-frequency ambient seismic wave field at the TCDP borehole
NASA Astrophysics Data System (ADS)
Hillers, G.; Campillo, M.; Lin, Y.-Y.; Ma, K.-F.; Roux, P.
2012-06-01
The Taiwan Chelungpu-fault Drilling Project (TCDP) installed a vertical seismic array between 950 and 1270 m depth in an active thrust fault environment. In this paper we analyze continuous noise records of the TCDP array between 1 and 16 Hz. We apply multiple array processing and noise correlation techniques to study the noise source process, properties of the propagation medium, and the ambient seismic wave field. Diurnal amplitude and slowness patterns suggest that noise is generated by cultural activity. The vicinity of the recording site to the excitation region, indicated by a narrow azimuthal distribution of propagation directions, leads to a predominant ballistic propagation regime. This is evident from the compatibility of the data with an incident plane wave model, polarized direct arrivals of noise correlation functions, and the asymmetric arrival shape. Evidence for contributions from scattering comes from equilibrated earthquake coda energy ratios, the frequency dependent randomization of propagation directions, and the existence of correlation coda waves. We conclude that the ballistic and scattered propagation regime coexist, where the first regime dominates the records, but the second is weaker yet not negligible. Consequently, the wave field is not equipartitioned. Correlation signal-to-noise ratios indicate a frequency dependent noise intensity. Iterations of the correlation procedure enhance the signature of the scattered regime. Discrepancies between phase velocities estimated from correlation functions and in-situ measurements are associated with the array geometry and its relative orientation to the predominant energy flux. The stability of correlation functions suggests their applicability in future monitoring efforts.
Nanoliter-droplet acoustic streaming via ultra high frequency surface acoustic waves.
Shilton, Richie J; Travagliati, Marco; Beltram, Fabio; Cecchini, Marco
2014-08-01
The relevant length scales in sub-nanometer amplitude surface acoustic wave-driven acoustic streaming are demonstrated. We demonstrate the absence of any physical limitations preventing the downscaling of SAW-driven internal streaming to nanoliter microreactors and beyond by extending SAW microfluidics up to operating frequencies in the GHz range. This method is applied to nanoliter scale fluid mixing.
High-frequency Surface Wave Measurements of Micro-tunamis generated by Glacier Calving
NASA Astrophysics Data System (ADS)
Minowa, Masahiro; Sugiyama, Shin; Sakakibara, Daiki; Podolskiy, Evgeny; Ohashi, Yoshihiko; Skvarca, Pedro
2016-04-01
Calving plays a key role in recent rapid retreat of glaciers in Greenland, Alaska and Patagonia. However, processes related to calving are poorly understood since direct observations are difficult. When calving occurred at the glacier front, ice hits water surface and generates surface wave or micro-tsunami. Because characteristics of the micro-tsunami are dependent on the impact on water, it is expected that analysis of the wave provides useful information on the size and type of calving. To study the calving processes from surface wave, we performed field observations at Glaciar Perito Moreno, a freshwater calving glacier in the Southern Patagonia Icefield. We measured the surface level by recording water pressure every 2 s (0.5 Hz), using a sensor installed in a lake 300 m from the calving front. Spectral and statistical analyses were performed on the wave data. We also carried out time-lapse photography, ice speed and water temperature measurements. The time-lapse photographs were used to identify the types of observed calving events (1. Subaqueous, 2. Topple, 3. Drop, 4. Small serac failure). During summer (15 December 2013-4 January 2014) and spring (6-20 October 2014) field campaigns, 640 (30 events d-1) and 195 (12 events d-1) calving events were recorded by the pressure sensor, respectively. The number of calving events varied in time (from 0 to 6 events h-1) and this variation correlates well with lakewater temperature. Subaqueous calving account for only 2.4 % of calving events recorded during the field campaigns (7 out of 364 events). These results imply importance of melting at/under water surface as a triggering mechanism of calving. Waves generated by subaerial calving events (type 2, 3 and 4) showed similar frequency spectrums, whereas those by subaqueous calving had smaller power in frequency range between 0.12-0.25 Hz. The amplitude of the surface waves increased with size of calving, which was quantified by the time-lapse photographs. Our results
Maxwellian theory of gravitational waves and their mechanical properties
NASA Astrophysics Data System (ADS)
Barnett, Stephen M.
2014-02-01
We present a theory in Maxwellian form for gravitational waves in a flat background. This requires us to identify the gravitational analogues of the electric and magnetic fields for light. An important novelty, however, is that our analogues are not vector fields but rather rank-two tensor fields; in place of a three-component vector at each point in space, as in electromagnetism, our fields are three by three symmetric matrices at each point. The resulting Maxwell-like equations lead directly to a Poynting theorem for the local energy density associated with a gravitational wave and to associated local properties including densities of momentum and angular momentum.
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.
NASA Astrophysics Data System (ADS)
Sotnikov, V.; Kim, T.; Lundberg, J.; Paraschiv, I.; Mehlhorn, T. A.
2014-10-01
Interchange or flute type density irregularities in magnetized plasma are associated with Rayleigh-Taylor type instability. In particular, we are interested in the generation of low frequency plasma density irregularities in the form of flute type vortex density structures and interaction of high frequency electromagnetic waves used for surveillance and communication with such structures. These types of density irregularities play an important role in refraction and scattering of high frequency electromagnetic signals propagating in the earth ionosphere, in high energy density physics (HEDP), and in many other applications. We will present PIC simulation results of EM scattering on vortex type density structures using the LSP code and compare them with analytical results. Two cases will be analyzed. In the first case electromagnetic wave scattering will take place in the ionospheric plasma. In the second case laser probing in a high-beta Z-pinch plasma will be presented. This work was supported by the Air Force Research laboratory, the Air Force Office of Scientific Research, the Naval Research Laboratory and NNSA/DOE Grant No. DE-FC52-06NA27616 at the University of Nevada at Reno.
CMB statistical anisotropy from noncommutative gravitational waves
NASA Astrophysics Data System (ADS)
Shiraishi, Maresuke; Mota, David F.; Ricciardone, Angelo; Arroja, Frederico
2014-07-01
Primordial statistical anisotropy is a key indicator to investigate early Universe models and has been probed by the cosmic microwave background (CMB) anisotropies. In this paper, we examine tensor-mode CMB fluctuations generated from anisotropic gravitational waves, parametrised by Ph(k) = Ph(0)(k) [ 1 + ∑LM fL(k) gLM YLM (hat k)], where Ph(0)(k) is the usual scale-invariant power spectrum. Such anisotropic tensor fluctuations may arise from an inflationary model with noncommutativity of fields. It is verified that in this model, an isotropic component and a quadrupole asymmetry with f0(k) = f2(k) propto k-2 are created and hence highly red-tilted off-diagonal components arise in the CMB power spectra, namely l2 = l1 ± 2 in TT, TE, EE and BB, and l2 = l1 ± 1 in TB and EB. We find that B-mode polarisation is more sensitive to such signals than temperature and E-mode polarisation due to the smallness of large-scale cosmic variance and we can potentially measure g00 = 30 and g2M = 58 at 68% CL in a cosmic-variance-limited experiment. Such a level of signal may be measured in a PRISM like experiment, while the instrumental noise contaminates it in the Planck experiment. These results imply that it is impossible to measure the noncommutative parameter if it is small enough for the perturbative treatment to be valid. Our formalism and methodology for dealing with the CMB tensor statistical anisotropy are general and straightforwardly applicable to other early Universe models.
Gravitational waves from Q-ball formation
Chiba, Takeshi; Kamada, Kohei; Yamaguchi, Masahide
2010-04-15
We study the detectability of the gravitational waves (GWs) from the Q-ball formation associated with the Affleck-Dine (AD) mechanism, taking into account both the dilution effects due to Q-ball domination and to finite temperature. The AD mechanism predicts the formation of nontopological solitons, Q-balls, from which GWs are generated. Q-balls with large conserved charge Q can produce a large amount of GWs. On the other hand, the decay rate of such Q-balls is so small that they may dominate the energy density of the Universe, which implies that GWs are significantly diluted and that their frequencies are redshifted during the Q-ball dominated era. Thus, the detectability of the GWs associated with the formation of Q-balls is determined by these two competing effects. We find that there is a finite but small parameter region where such GWs may be detected by future detectors such as DECIGO or BBO, only in the case when the thermal logarithmic potential dominates the potential of the AD field. Otherwise GWs from Q-balls would not be detectable even by these futuristic detectors: {Omega}{sub GW}{sup 0}<10{sup -21}. Unfortunately, for such parameter region the present baryon asymmetry of the Universe can hardly be explained unless one fine-tunes A-terms in the potential. However the detection of such a GW background may give us an information about the early Universe, for example, it may suggest that the flat directions with B-L=0 are favored.
Potential damage to DC superconducting magnets due to the high frequency electromagnetic waves
NASA Technical Reports Server (NTRS)
Gabriel, G. J.
1977-01-01
Experimental data are presented in support of the hypothesis that a dc superconducting magnet coil does not behave strictly as an inductor, but as a complicated electrodynamic device capable of supporting electromagnetic waves. Travel times of nanosecond pulses and evidence of sinusoidal standing waves were observed on a prototype four-layer solenoidal coil at room temperature. Ringing observed during switching transients appears as a sequence of multiple reflected square pulses whose durations are related to the layer lengths. With sinusoidal excitation of the coil, the voltage amplitude between a pair of points on the coil exhibits maxima at those frequencies such that the distance between these points is an odd multiple of half wavelength in free space. Evidence indicates that any disturbance, such as that resulting from switching or sudden fault, initiates multiple reflections between layers, thus raising the possibility for sufficiently high voltages to cause breakdown.
Ang, Kar M; Yeo, Leslie Y; Hung, Yew M; Tan, Ming K
2016-09-21
The deposition of a thin graphene film atop a chip scale piezoelectric substrate on which surface acoustic waves are excited is observed to enhance its performance for fluid transport and manipulation considerably, which can be exploited to achieve further efficiency gains in these devices. Such gains can then enable complete integration and miniaturization for true portability for a variety of microfluidic applications across drug delivery, biosensing and point-of-care diagnostics, among others, where field-use, point-of-collection or point-of-care functionality is desired. In addition to a first demonstration of vibration-induced molecular transport in graphene films, we show that the coupling of the surface acoustic wave gives rise to antisymmetric Lamb waves in the film which enhance molecular diffusion and hence the flow through the interstitial layers that make up the film. Above a critical input power, the strong substrate vibration displacement can also force the molecules out of the graphene film to form a thin fluid layer, which subsequently destabilizes and breaks up to form a mist of micron dimension aerosol droplets. We provide physical insight into this coupling through a simple numerical model, verified through experiments, and show several-fold improvement in the rate of fluid transport through the film, and up to 55% enhancement in the rate of fluid atomization from the film using this simple method. PMID:27502324
Pulsar timing arrays: the promise of gravitational wave detection
NASA Astrophysics Data System (ADS)
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.
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.
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. PMID:26564968
NONLINEAR GRAVITATIONAL-WAVE MEMORY FROM BINARY BLACK HOLE MERGERS
Favata, Marc
2009-05-10
Some astrophysical sources of gravitational waves can produce a 'memory effect', which causes a permanent displacement of the test masses in a freely falling gravitational-wave detector. The Christodoulou memory is a particularly interesting nonlinear form of memory that arises from the gravitational-wave stress-energy tensor's contribution to the distant gravitational-wave field. This nonlinear memory contributes a nonoscillatory component to the gravitational-wave signal at leading (Newtonian-quadrupole) order in the waveform amplitude. Previous computations of the memory and its detectability considered only the inspiral phase of binary black hole coalescence. Using an 'effective-one-body' (EOB) approach calibrated to numerical relativity simulations, as well as a simple fully analytic model, the Christodoulou memory is computed for the inspiral, merger, and ringdown. The memory will be very difficult to detect with ground-based interferometers, but is likely to be observable in supermassive black hole mergers with LISA out to redshifts z {approx}< 2. Detection of the nonlinear memory could serve as an experimental test of the ability of gravity to 'gravitate'.
Newtorites in bar detectors of gravitational wave
NASA Astrophysics Data System (ADS)
Ronga, F.;
2016-05-01
The detection of particles with only gravitational interactions (Newtorites) in gravitational bar detectors was studied in 1984 by Bernard, De Rujula and Lautrup. The negative results of dark matter searches suggest to look to exotic possibilities like Newtorites. The limits obtained with the Nautilus bar detector will be presented and the possible improvements will be discussed. Since the gravitational coupling is very weak, the possible limits are very far from what is needed for dark matter, but for large masses are the best limits obtained on the Earth. An update of limits for MACRO particles will be given.
NASA Astrophysics Data System (ADS)
Lu, Wangtao; Qian, Jianliang; Burridge, Robert
2016-05-01
In some applications, it is reasonable to assume that geodesics (rays) have a consistent orientation so that the Helmholtz equation can be viewed as an evolution equation in one of the spatial directions. With such applications in mind, starting from Babich's expansion, we develop a new high-order asymptotic method, which we dub the fast Huygens sweeping method, for solving point-source Helmholtz equations in inhomogeneous media in the high-frequency regime and in the presence of caustics. The first novelty of this method is that we develop a new Eulerian approach to compute the asymptotics, i.e. the traveltime function and amplitude coefficients that arise in Babich's expansion, yielding a locally valid solution, which is accurate close enough to the source. The second novelty is that we utilize the Huygens-Kirchhoff integral to integrate many locally valid wavefields to construct globally valid wavefields. This automatically treats caustics and yields uniformly accurate solutions both near the source and remote from it. The third novelty is that the butterfly algorithm is adapted to accelerate the Huygens-Kirchhoff summation, achieving nearly optimal complexity O (Nlog N), where N is the number of mesh points; the complexity prefactor depends on the desired accuracy and is independent of the frequency. To reduce the storage of the resulting tables of asymptotics in Babich's expansion, we use the multivariable Chebyshev series expansion to compress each table by encoding the information into a small number of coefficients. The new method enjoys the following desired features. First, it precomputes the asymptotics in Babich's expansion, such as traveltime and amplitudes. Second, it takes care of caustics automatically. Third, it can compute the point-source Helmholtz solution for many different sources at many frequencies simultaneously. Fourth, for a specified number of points per wavelength, it can construct the wavefield in nearly optimal complexity in terms
NASA Astrophysics Data System (ADS)
Moradi, Afshin
2016-09-01
Propagation of magnetoplasma waves at an angle to a static magnetic field is studied for a random distribution of spherical metallic nanoparticles. A general analytical expression for dispersion relation of the system is derived and useful expressions are obtained in the limiting cases. It is found that the interaction between longitudinal and transverse modes leads to coupled modes in the vicinity of the frequency √ {f + ξ } {ω _p}, where ξ is the ratio of the volume occupied by all the nanoparticles to the entire volume, ωp the plasma frequency of electrons inside a nanoparticle, and f a geometrical factor of order unity (1/3 for spherical nanoparticles).
Potential damage to dc superconducting magnets due to high frequency electromagnetic waves
NASA Technical Reports Server (NTRS)
Gabriel, G. J.; Burkhart, J. A.
1977-01-01
Studies of a d.c. superconducting magnet coil indicate that the large coil behaves as a straight waveguide structure. Voltages between layers within the coil sometimes exceeded those recorded at terminals where protective resistors are located. Protection of magnet coils against these excessive voltages could be accomplished by impedance matching throughout the coil system. The wave phenomenon associated with superconducting magnetic coils may create an instability capable of converting the energy of a quiescent d.c. superconducting coil into dissipative a.c. energy, even in cases when dielectric breakdown does not take place.
Wang, Ying; Rezk, Amgad R; Khara, Jasmeet Singh; Yeo, Leslie Y; Ee, Pui Lai Rachel
2016-05-01
Surface acoustic wave (SAW), a nanometer amplitude electroelastic wave generated and propagated on low-loss piezoelectric substrates (such as LiNbO3), is an extremely efficient solid-fluid energy transfer mechanism. The present study explores the use of SAW nebulization as a solution for effective pulmonary peptide delivery. In vitro deposition characteristics of the nebulized peptides were determined using a Next Generation Cascade Impactor. 70% of the peptide-laden aerosols generated were within a size distribution favorable for deep lung distribution. The integrity of the nebulized peptides was found to be retained, as shown via mass spectrometry. The anti-mycobacterial activity of the nebulized peptides was found to be uncompromised compared with their non-nebulized counterparts, as demonstrated by the minimum inhibition concentration and the colony forming inhibition activity. The peptide concentration and volume recoveries for the SAW nebulizer were significantly higher than 90% and found to be insensitive to variation in the peptide sequences. These results demonstrate the potential of the SAW nebulization platform as an effective delivery system of therapeutic peptides through the respiratory tract to the deep lung. PMID:27375820
Pyle, Moira L.; Koper, Keith D.; Euler, Garrett G.; Burlacu, Relu
2015-04-20
We investigate source locations of P-wave microseisms within a narrow frequency band (0.67–1.33 Hz) that is significantly higher than the classic microseism band (~0.05–0.3 Hz). Employing a backprojection method, we analyze data recorded during January 2010 from five International Monitoring System arrays that border the Pacific Ocean. We develop a ranking scheme that allows us to combine beam power from multiple arrays to obtain robust locations of the microseisms. Some individual arrays exhibit a strong regional component, but results from the combination of all arrays show high-frequency P wave energy emanating from the North Pacific basin, in general agreement withmore » previous observations in the double-frequency (DF) microseism band (~0.1–0.3 Hz). This suggests that the North Pacific source of ambient P noise covers a broad range of frequencies and that the wave-wave interaction model is likely valid at shorter periods.« less
Squeezed states in the theory of primordial gravitational waves
NASA Technical Reports Server (NTRS)
Grishchuk, Leonid P.
1992-01-01
It is shown that squeezed states of primordial gravitational waves are inevitably produced in the course of cosmological evolution. The theory of squeezed gravitons is very similar to the theory of squeezed light. Squeezed parameters and statistical properties of the expected relic gravity-wave radiation are described.
Clustering correlations and limits on cosmological gravitational waves
NASA Technical Reports Server (NTRS)
Linder, Eric V.
1988-01-01
A cosmological background of gravitational waves induces angular deviations in the propagation of light traversing it. All observed astrophysical sources might therefore have varying apparent positions, with the time dependence set by the wave period. Wavelengths greater than a kiloparsec are examined, so the positions are frozen but in general correlated. Comparison with observed galaxy-galaxy n-point correlation functions provide a spectrum-independent limit on the energy density of gravitational waves with wavelengths between a few tens of kiloparsecs and a few hundred megaparsecs of Omega(GW) less than 0.001.
Atom Interferometry for Detection of Gravitational Waves: Progress and Prospects
NASA Astrophysics Data System (ADS)
Hogan, Jason
2015-04-01
Gravitational wave astronomy promises to provide a new window into the universe, collecting information about astrophysical systems and cosmology that is difficult or impossible to acquire by other methods. Detector designs based on atom interferometry offer a number of advantages over traditional approaches, including access to conventionally inaccessible frequency ranges and substantially reduced antenna baselines. Atomic physics techniques also make it possible to build a gravitational wave detector with a single linear baseline, potentially offering advantages in cost and design flexibility. In support of these proposals, recent progress in long baseline atom interferometry has enabled observation of matter wave interference with atomic wavepacket separations exceeding 10 cm and interferometer durations of more than 2 seconds. These results are obtained in a 10-meter drop tower incorporating large momentum transfer atom optics. This approach can provide ground-based proof-of-concept demonstrations of many of the technical requirements of both terrestrial and satellite gravitational wave detectors.
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
CMB statistical anisotropy from noncommutative gravitational waves
Shiraishi, Maresuke; Ricciardone, Angelo; Mota, David F.; Arroja, Frederico E-mail: d.f.mota@astro.uio.no E-mail: arroja@pd.infn.it
2014-07-01
Primordial statistical anisotropy is a key indicator to investigate early Universe models and has been probed by the cosmic microwave background (CMB) anisotropies. In this paper, we examine tensor-mode CMB fluctuations generated from anisotropic gravitational waves, parametrised by P{sub h}(k) = P{sub h}{sup (0)}(k) [ 1 + ∑{sub LM} f{sub L}(k) g{sub LM} Y{sub LM} ( k-circumflex )], where P{sub h}{sup (0)}(k) is the usual scale-invariant power spectrum. Such anisotropic tensor fluctuations may arise from an inflationary model with noncommutativity of fields. It is verified that in this model, an isotropic component and a quadrupole asymmetry with f{sub 0}(k) = f{sub 2}(k) ∝ k{sup -2} are created and hence highly red-tilted off-diagonal components arise in the CMB power spectra, namely ℓ{sub 2} = ℓ{sub 1} ± 2 in TT, TE, EE and BB, and ℓ{sub 2} = ℓ{sub 1} ± 1 in TB and EB. We find that B-mode polarisation is more sensitive to such signals than temperature and E-mode polarisation due to the smallness of large-scale cosmic variance and we can potentially measure g{sub 00} = 30 and g{sub 2M} = 58 at 68% CL in a cosmic-variance-limited experiment. Such a level of signal may be measured in a PRISM like experiment, while the instrumental noise contaminates it in the Planck experiment. These results imply that it is impossible to measure the noncommutative parameter if it is small enough for the perturbative treatment to be valid. Our formalism and methodology for dealing with the CMB tensor statistical anisotropy are general and straightforwardly applicable to other early Universe models.
Soghomonyan, Diana; Trchounian, Karen; Trchounian, Armen
2016-06-01
Millimeter waves (MMW) or electromagnetic fields of extremely high frequencies at low intensity is a new environmental factor, the level of which is increased as technology advance. It is of interest that bacteria and other cells might communicate with each other by electromagnetic field of sub-extremely high frequency range. These MMW affected Escherichia coli and many other bacteria, mainly depressing their growth and changing properties and activity. These effects were non-thermal and depended on different factors. The significant cellular targets for MMW effects could be water, cell plasma membrane, and genome. The model for the MMW interaction with bacteria is suggested; a role of the membrane-associated proton FOF1-ATPase, key enzyme of bioenergetic relevance, is proposed. The consequences of MMW interaction with bacteria are the changes in their sensitivity to different biologically active chemicals, including antibiotics. Novel data on MMW effects on bacteria and their sensitivity to different antibiotics are presented and discussed; the combined action of MMW and antibiotics resulted with more strong effects. These effects are of significance for understanding changed metabolic pathways and distinguish role of bacteria in environment; they might be leading to antibiotic resistance in bacteria. The effects might have applications in the development of technique, therapeutic practices, and food protection technology. PMID:27087527
NASA Astrophysics Data System (ADS)
Toyota, Koudai
2016-10-01
The method of the envelope Hamiltonian [K. Toyota, U. Saalmann, and J. M. Rost, New J. Phys. 17, 073005 (2015), 10.1088/1367-2630/17/7/073005] is applied to further study a detachment dynamics of a model negative ion in one dimension in the high-frequency regime. This method is based on the Floquet approach, but the time dependency of an envelope function is explicitly kept for arbitrary pulse durations. Therefore, it is capable of describing not only a photon absorption or emission, but also a nonadiabatic transition which is induced by the time-varying envelope of the pulse. It was shown that the envelope Hamiltonian accurately retrieves the results obtained by the time-dependent Schrödinger equation, and the underlying physics were well understood by the adiabatic approximation based on the envelope Hamiltonian. In this paper, we explore two more aspects of the detachment dynamics, which were not considered in our previous work. First, we determine the features of both a spatial and temporal interference of photoelectron wave packets in a photon-absorption process. We conclude that both of the interference mechanisms are universal in ionization dynamics in the high-frequency regime. Second, we extract a pulse duration which maximizes a yield of the nonadiabatic transition as a function of a pulse duration. It is shown that it becomes maximum when the pulse duration is comparable to a time scale of an electron.
Soghomonyan, Diana; Trchounian, Karen; Trchounian, Armen
2016-06-01
Millimeter waves (MMW) or electromagnetic fields of extremely high frequencies at low intensity is a new environmental factor, the level of which is increased as technology advance. It is of interest that bacteria and other cells might communicate with each other by electromagnetic field of sub-extremely high frequency range. These MMW affected Escherichia coli and many other bacteria, mainly depressing their growth and changing properties and activity. These effects were non-thermal and depended on different factors. The significant cellular targets for MMW effects could be water, cell plasma membrane, and genome. The model for the MMW interaction with bacteria is suggested; a role of the membrane-associated proton FOF1-ATPase, key enzyme of bioenergetic relevance, is proposed. The consequences of MMW interaction with bacteria are the changes in their sensitivity to different biologically active chemicals, including antibiotics. Novel data on MMW effects on bacteria and their sensitivity to different antibiotics are presented and discussed; the combined action of MMW and antibiotics resulted with more strong effects. These effects are of significance for understanding changed metabolic pathways and distinguish role of bacteria in environment; they might be leading to antibiotic resistance in bacteria. The effects might have applications in the development of technique, therapeutic practices, and food protection technology.
NASA Astrophysics Data System (ADS)
Lu, B.; Darmon, M.; Leymarie, N.; Chatillon, S.; Potel, C.
2012-05-01
In-service inspection of Sodium-Cooled Fast Reactors (SFR) requires the development of non-destructive techniques adapted to the harsh environment conditions and the examination complexity. From past experiences, ultrasonic techniques are considered as suitable candidates. The ultrasonic telemetry is a technique used to constantly insure the safe functioning of reactor inner components by determining their exact position: it consists in measuring the time of flight of the ultrasonic response obtained after propagation of a pulse emitted by a transducer and its interaction with the targets. While in-service the sodium flow creates turbulences that lead to temperature inhomogeneities, which translates into ultrasonic velocity inhomogeneities. These velocity variations could directly impact the accuracy of the target locating by introducing time of flight variations. A stochastic simulation model has been developed to calculate the propagation of ultrasonic waves in such an inhomogeneous medium. Using this approach, the travel time is randomly generated by a stochastic process whose inputs are the statistical moments of travel times known analytically. The stochastic model predicts beam deviations due to velocity inhomogeneities, which are similar to those provided by a determinist method, such as the ray method.
Lu, B.; Darmon, M.; Leymarie, N.; Chatillon, S.; Potel, C.
2012-05-17
In-service inspection of Sodium-Cooled Fast Reactors (SFR) requires the development of non-destructive techniques adapted to the harsh environment conditions and the examination complexity. From past experiences, ultrasonic techniques are considered as suitable candidates. The ultrasonic telemetry is a technique used to constantly insure the safe functioning of reactor inner components by determining their exact position: it consists in measuring the time of flight of the ultrasonic response obtained after propagation of a pulse emitted by a transducer and its interaction with the targets. While in-service the sodium flow creates turbulences that lead to temperature inhomogeneities, which translates into ultrasonic velocity inhomogeneities. These velocity variations could directly impact the accuracy of the target locating by introducing time of flight variations. A stochastic simulation model has been developed to calculate the propagation of ultrasonic waves in such an inhomogeneous medium. Using this approach, the travel time is randomly generated by a stochastic process whose inputs are the statistical moments of travel times known analytically. The stochastic model predicts beam deviations due to velocity inhomogeneities, which are similar to those provided by a determinist method, such as the ray method.
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.
Observation of Gravitational Waves from a Binary Black Hole Merger.
Abbott, B P; Abbott, R; Abbott, T D; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V B; Affeldt, C; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Aiello, L; Ain, A; Ajith, P; Allen, B; Allocca, A; Altin, P A; Anderson, S B; Anderson, W G; Arai, K; Arain, M A; Araya, M C; Arceneaux, C C; Areeda, J S; Arnaud, N; Arun, K G; Ascenzi, S; Ashton, G; Ast, M; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Babak, S; Bacon, P; Bader, M K M; Baker, P T; Baldaccini, F; Ballardin, G; Ballmer, S W; Barayoga, J C; Barclay, S E; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barta, D; Bartlett, J; Barton, M A; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Baune, C; Bavigadda, V; Bazzan, M; Behnke, B; Bejger, M; Belczynski, C; Bell, A S; Bell, C J; Berger, B K; Bergman, J; Bergmann, G; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Birch, J; Birney, R; Birnholtz, O; Biscans, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blair, C D; Blair, D G; Blair, R M; Bloemen, S; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bogan, C; Bohe, A; Bojtos, P; Bond, C; Bondu, F; Bonnand, R; Boom, B A; Bork, R; Boschi, V; Bose, S; Bouffanais, Y; Bozzi, A; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Brillet, A; Brinkmann, M; Brisson, V; Brockill, P; Brooks, A F; Brown, D A; Brown, D D; Brown, N M; Buchanan, C C; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Byer, R L; Cabero, M; Cadonati, L; Cagnoli, G; Cahillane, C; Calderón Bustillo, J; Callister, T; Calloni, E; Camp, J B; Cannon, K C; Cao, J; Capano, C D; Capocasa, E; Carbognani, F; Caride, S; Casanueva Diaz, J; Casentini, C; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C B; Cerboni Baiardi, L; Cerretani, G; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chan, M; Chao, S; Charlton, P; Chassande-Mottin, E; Chen, H Y; Chen, Y; Cheng, C; Chincarini, A; Chiummo, A; Cho, H S; Cho, M; Chow, J H; Christensen, N; Chu, Q; Chua, S; Chung, S; Ciani, G; Clara, F; Clark, J A; Cleva, F; Coccia, E; Cohadon, P-F; Colla, A; Collette, C G; Cominsky, L; Constancio, M; Conte, A; Conti, L; Cook, D; Corbitt, T R; Cornish, N; Corsi, A; Cortese, S; Costa, C A; Coughlin, M W; Coughlin, S B; Coulon, J-P; Countryman, S T; Couvares, P; Cowan, E E; Coward, D M; Cowart, M J; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Creighton, T D; Cripe, J; Crowder, S G; Cruise, A M; Cumming, A; Cunningham, L; Cuoco, E; Dal Canton, T; Danilishin, S L; D'Antonio, S; Danzmann, K; Darman, N S; Da Silva Costa, C F; Dattilo, V; Dave, I; Daveloza, H P; Davier, M; Davies, G S; Daw, E J; Day, R; De, S; DeBra, D; Debreczeni, G; Degallaix, J; De Laurentis, M; Deléglise, S; Del Pozzo, W; Denker, T; Dent, T; Dereli, H; Dergachev, V; DeRosa, R T; De Rosa, R; DeSalvo, R; Dhurandhar, S; Díaz, M C; Di Fiore, L; Di Giovanni, M; Di Lieto, A; Di Pace, S; Di Palma, I; Di Virgilio, A; Dojcinoski, G; Dolique, V; Donovan, F; Dooley, K L; Doravari, S; Douglas, R; Downes, T P; Drago, M; Drever, R W P; Driggers, J C; Du, Z; Ducrot, M; Dwyer, S E; Edo, T B; Edwards, M C; Effler, A; Eggenstein, H-B; Ehrens, P; Eichholz, J; Eikenberry, S S; Engels, W; Essick, R C; Etzel, T; Evans, M; Evans, T M; Everett, R; Factourovich, M; Fafone, V; Fair, H; Fairhurst, S; Fan, X; Fang, Q; Farinon, S; Farr, B; Farr, W M; Favata, M; Fays, M; Fehrmann, H; Fejer, M M; Feldbaum, D; Ferrante, I; Ferreira, E C; Ferrini, F; Fidecaro, F; Finn, L S; Fiori, I; Fiorucci, D; Fisher, R P; Flaminio, R; Fletcher, M; Fong, H; Fournier, J-D; Franco, S; Frasca, S; Frasconi, F; Frede, M; Frei, Z; Freise, A; Frey, R; Frey, V; Fricke, T T; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gabbard, H A G; Gair, J R; Gammaitoni, L; Gaonkar, S G; Garufi, F; Gatto, A; Gaur, G; Gehrels, N; Gemme, G; Gendre, B; Genin, E; Gennai, A; George, J; Gergely, L; Germain, V; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, K; Glaefke, A; Gleason, J R; Goetz, E; Goetz, R; Gondan, L; González, G; 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; 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
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. PMID:26918975
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.
Observation of Gravitational Waves from a Binary Black Hole Merger.
Abbott, B P; Abbott, R; Abbott, T D; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Adya, V B; Affeldt, C; Agathos, M; Agatsuma, K; Aggarwal, N; Aguiar, O D; Aiello, L; Ain, A; Ajith, P; Allen, B; Allocca, A; Altin, P A; Anderson, S B; Anderson, W G; Arai, K; Arain, M A; Araya, M C; Arceneaux, C C; Areeda, J S; Arnaud, N; Arun, K G; Ascenzi, S; Ashton, G; Ast, M; Aston, S M; Astone, P; Aufmuth, P; Aulbert, C; Babak, S; Bacon, P; Bader, M K M; Baker, P T; Baldaccini, F; Ballardin, G; Ballmer, S W; Barayoga, J C; Barclay, S E; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barta, D; Bartlett, J; Barton, M A; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Baune, C; Bavigadda, V; Bazzan, M; Behnke, B; Bejger, M; Belczynski, C; Bell, A S; Bell, C J; Berger, B K; Bergman, J; Bergmann, G; Berry, C P L; Bersanetti, D; Bertolini, A; Betzwieser, J; Bhagwat, S; Bhandare, R; Bilenko, I A; Billingsley, G; Birch, J; Birney, R; Birnholtz, O; Biscans, S; Bisht, A; Bitossi, M; Biwer, C; Bizouard, M A; Blackburn, J K; Blair, C D; Blair, D G; Blair, R M; Bloemen, S; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bogan, C; Bohe, A; Bojtos, P; Bond, C; Bondu, F; Bonnand, R; Boom, B A; Bork, R; Boschi, V; Bose, S; Bouffanais, Y; Bozzi, A; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Brillet, A; Brinkmann, M; Brisson, V; Brockill, P; Brooks, A F; Brown, D A; Brown, D D; Brown, N M; Buchanan, C C; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Buskulic, D; Buy, C; Byer, R L; Cabero, M; Cadonati, L; Cagnoli, G; Cahillane, C; Calderón Bustillo, J; Callister, T; Calloni, E; Camp, J B; Cannon, K C; Cao, J; Capano, C D; Capocasa, E; Carbognani, F; Caride, S; Casanueva Diaz, J; Casentini, C; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Cella, G; Cepeda, C B; Cerboni Baiardi, L; Cerretani, G; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chan, M; Chao, S; Charlton, P; Chassande-Mottin, E; Chen, H Y; Chen, Y; Cheng, C; Chincarini, A; Chiummo, A; Cho, H S; Cho, M; Chow, J H; Christensen, N; Chu, Q; Chua, S; Chung, S; Ciani, G; Clara, F; Clark, J A; Cleva, F; Coccia, E; Cohadon, P-F; Colla, A; Collette, C G; Cominsky, L; Constancio, M; Conte, A; Conti, L; Cook, D; Corbitt, T R; Cornish, N; Corsi, A; Cortese, S; Costa, C A; Coughlin, M W; Coughlin, S B; Coulon, J-P; Countryman, S T; Couvares, P; Cowan, E E; Coward, D M; Cowart, M J; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Creighton, T D; Cripe, J; Crowder, S G; Cruise, A M; Cumming, A; Cunningham, L; Cuoco, E; Dal Canton, T; Danilishin, S L; D'Antonio, S; Danzmann, K; Darman, N S; Da Silva Costa, C F; Dattilo, V; Dave, I; Daveloza, H P; Davier, M; Davies, G S; Daw, E J; Day, R; De, S; DeBra, D; Debreczeni, G; Degallaix, J; De Laurentis, M; Deléglise, S; Del Pozzo, W; Denker, T; Dent, T; Dereli, H; Dergachev, V; DeRosa, R T; De Rosa, R; DeSalvo, R; Dhurandhar, S; Díaz, M C; Di Fiore, L; Di Giovanni, M; Di Lieto, A; Di Pace, S; Di Palma, I; Di Virgilio, A; Dojcinoski, G; Dolique, V; Donovan, F; Dooley, K L; Doravari, S; Douglas, R; Downes, T P; Drago, M; Drever, R W P; Driggers, J C; Du, Z; Ducrot, M; Dwyer, S E; Edo, T B; Edwards, M C; Effler, A; Eggenstein, H-B; Ehrens, P; Eichholz, J; Eikenberry, S S; Engels, W; Essick, R C; Etzel, T; Evans, M; Evans, T M; Everett, R; Factourovich, M; Fafone, V; Fair, H; Fairhurst, S; Fan, X; Fang, Q; Farinon, S; Farr, B; Farr, W M; Favata, M; Fays, M; Fehrmann, H; Fejer, M M; Feldbaum, D; Ferrante, I; Ferreira, E C; Ferrini, F; Fidecaro, F; Finn, L S; Fiori, I; Fiorucci, D; Fisher, R P; Flaminio, R; Fletcher, M; Fong, H; Fournier, J-D; Franco, S; Frasca, S; Frasconi, F; Frede, M; Frei, Z; Freise, A; Frey, R; Frey, V; Fricke, T T; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gabbard, H A G; Gair, J R; Gammaitoni, L; Gaonkar, S G; Garufi, F; Gatto, A; Gaur, G; Gehrels, N; Gemme, G; Gendre, B; Genin, E; Gennai, A; George, J; Gergely, L; Germain, V; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gill, K; Glaefke, A; Gleason, J R; Goetz, E; Goetz, R; Gondan, L; González, G; 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; 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
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.
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.
Gravitational waves in viable f(R) models
Yang, Louis; Lee, Chung-Chi; Geng, Chao-Qiang E-mail: geng@phys.nthu.edu.tw
2011-08-01
We study gravitational waves in viable f(R) theories under a non-zero background curvature. In general, an f(R) theory contains an extra scalar degree of freedom corresponding to a massive scalar mode of gravitational wave. For viable f(R) models, since there always exits a de-Sitter point where the background curvature in vacuum is non-zero, the mass squared of the scalar mode of gravitational wave is about the de-Sitter point curvature R{sub d} ∼ 10{sup −66}eV{sup 2}. We illustrate our results in two types of viable f(R) models: the exponential gravity and Starobinsky models. In both cases, the mass will be in the order of 10{sup −33}eV when it propagates in vacuum. However, in the presence of matter density in galaxy, the scalar mode can be heavy. Explicitly, in the exponential gravity model, the mass becomes almost infinity, implying the disappearance of the scalar mode of gravitational wave, while the Starobinsky model gives the lowest mass around 10{sup −24}eV, corresponding to the lowest frequency of 10{sup −9} Hz, which may be detected by the current and future gravitational wave probes, such as LISA and ASTROD-GW.
Gravitational waves from a very strong electroweak phase transition
NASA Astrophysics Data System (ADS)
Leitao, Leonardo; Mégevand, Ariel
2016-05-01
We investigate the production of a stochastic background of gravitational waves in the electroweak phase transition. We consider extensions of the Standard Model which can give very strongly first-order phase transitions, such that the transition fronts either propagate as detonations or run away. To compute the bubble wall velocity, we estimate the friction with the plasma and take into account the hydrodynamics. We track the development of the phase transition up to the percolation time, and we calculate the gravitational wave spectrum generated by bubble collisions, magnetohydrodynamic turbulence, and sound waves. For the kinds of models we consider, we find parameter regions for which the gravitational waves are potentially observable at the planned space-based interferometer eLISA. In such cases, the signal from sound waves is generally dominant, while that from bubble collisions is the least significant of them. Since the sound waves and turbulence mechanisms are diminished for runaway walls, the models with the best prospects of detection at eLISA are those which do not have such solutions. In particular, we find that heavy extra bosons provide stronger gravitational wave signals than tree-level terms.
The generation of gravitational waves. III - Derivation of bremsstrahlung formulae
NASA Technical Reports Server (NTRS)
Kovacs, S. J.; Thorne, K. S.
1977-01-01
Formulas are derived describing the gravitational waves produced by a stellar encounter of the following type. The two stars have stationary (i.e., nonpulsating) nearly Newtonian structures with arbitrary relative masses; they fly past each other with an arbitrary relative velocity; and their impact parameter is sufficiently large that they gravitationally deflect each other through an angle that is small as compared with 90 deg.
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. PMID:16384203
The Scientific Potential of Space-Based Gravitational Wave Detectors
NASA Astrophysics Data System (ADS)
Gair, Jonathan R.
The millihertz gravitational wave band can only be accessed with a space-based interferometer, but it is one of the richest in potential sources. Observations in this band have amazing scientific potential. The mergers between massive black holes with mass in the range 104-107M_{⊙}, which are expected to occur following the mergers of their host galaxies, produce strong millihertz gravitational radiation. Observations of these systems will trace the hierarchical assembly of structure in the Universe in a mass range that is very difficult to probe electromagnetically. Stellar mass compact objects falling into such black holes in the centres of galaxies generate detectable gravitational radiation for several years prior to the final plunge and merger with the central black hole. Measurements of these systems offer an unprecedented opportunity to probe the predictions of general relativity in the strong-field and dynamical regime. Millihertz gravitational waves are also generated by millions of ultra-compact binaries in the Milky Way, providing a new way to probe galactic stellar populations. ESA has recognised this great scientific potential by selecting The Gravitational Universe as its theme for the L3 large satellite mission, scheduled for launch in ˜ 2034. In this article we will review the likely sources for millihertz gravitational wave detectors and describe the wide applications that observations of these sources could have for astrophysics, cosmology and fundamental physics.
Studying inflation with future space-based gravitational wave detectors
Jinno, Ryusuke; Moroi, Takeo; Takahashi, Tomo E-mail: moroi@phys.s.u-tokyo.ac.jp
2014-12-01
Motivated by recent progress in our understanding of the B-mode polarization of cosmic microwave background (CMB), which provides important information about the inflationary gravitational waves (IGWs), we study the possibility to acquire information about the early universe using future space-based gravitational wave (GW) detectors. We perform a detailed statistical analysis to estimate how well we can determine the reheating temperature after inflation as well as the amplitude, the tensor spectral index, and the running of the inflationary gravitational waves. We discuss how the accuracies depend on noise parameters of the detector and the minimum frequency available in the analysis. Implication of such a study on the test of inflation models is also discussed.
GRAVITATIONAL WAVES OF JET PRECESSION IN GAMMA-RAY BURSTS
Sun Mouyuan; Liu Tong; Gu Weimin; Lu Jufu
2012-06-10
The physical nature of gamma-ray bursts (GRBs) is believed to involve an ultra-relativistic jet. The observed complex structure of light curves motivates the idea of jet precession. In this work, we study the gravitational waves of jet precession based on neutrino-dominated accretion disks around black holes, which may account for the central engine of GRBs. In our model, the jet and the inner part of the disk may precess along with the black hole, which is driven by the outer part of the disk. Gravitational waves are therefore expected to be significant from this black-hole-inner-disk precession system. By comparing our numerical results with the sensitivity of some detectors, we find that it is possible for DECIGO and BBO to detect such gravitational waves, particularly for GRBs in the Local Group.
Detecting stochastic backgrounds of gravitational waves with pulsar timing arrays
NASA Astrophysics Data System (ADS)
Siemens, Xavier
2016-03-01
For the past decade the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) has been using the Green Bank Telescope and the Arecibo Observatory to monitor millisecond pulsars. NANOGrav, along with two other international collaborations, the European Pulsar Timing Array and the Parkes Pulsar Timing Array in Australia, form a consortium of consortia: the International Pulsar Timing Array (IPTA). The goal of the IPTA is to directly detect low-frequency gravitational waves which cause small changes to the times of arrival of radio pulses from millisecond pulsars. In this talk I will discuss the work of NANOGrav and the IPTA, as well as our sensitivity to stochastic backgrounds of gravitational waves. I will show that a detection of the background produced by supermassive black hole binaries is possible by the end of the decade. Supported by the NANOGrav Physics Frontiers Center.
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.
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.
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.
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. PMID:27015470
Discriminating between a stochastic gravitational wave background and instrument noise
Adams, Matthew R.; Cornish, Neil J.
2010-07-15
The detection of a stochastic background of gravitational waves could significantly impact our understanding of the physical processes that shaped the early Universe. The challenge lies in separating the cosmological signal from other stochastic processes such as instrument noise and astrophysical foregrounds. One approach is to build two or more detectors and cross correlate their output, thereby enhancing the common gravitational wave signal relative to the uncorrelated instrument noise. When only one detector is available, as will likely be the case with the Laser Interferometer Space Antenna (LISA), alternative analysis techniques must be developed. Here we show that models of the noise and signal transfer functions can be used to tease apart the gravitational and instrument noise contributions. We discuss the role of gravitational wave insensitive ''null channels'' formed from particular combinations of the time delay interferometry, and derive a new combination that maintains this insensitivity for unequal arm-length detectors. We show that, in the absence of astrophysical foregrounds, LISA could detect signals with energy densities as low as {Omega}{sub gw}=6x10{sup -13} with just one month of data. We describe an end-to-end Bayesian analysis pipeline that is able to search for, characterize and assign confidence levels for the detection of a stochastic gravitational wave background, and demonstrate the effectiveness of this approach using simulated data from the third round of Mock LISA Data Challenges.
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.
Gravitational waves from first-order cosmological phase transitions
NASA Technical Reports Server (NTRS)
Kosowsky, Arthur; Turner, Michael S.; Watkins, Richard
1992-01-01
A first-order cosmological phase transition that proceeds through the nucleation and collision of true-vacuum bubbles is a potent source of gravitational radiation. Possibilities for such include first-order inflation, grand-unified-theory-symmetry breaking, and electroweak-symmetry breaking. We have calculated gravity-wave production from the collision of two scalar-field vacuum bubbles, and, using an approximation based upon these results, from the collision of 20 to 30 vacuum bubbles. We present estimates of the relic background of gravitational waves produced by a first-order phase transition.
Parameter estimation on gravitational waves from multiple coalescing binaries
Mandel, Ilya
2010-04-15
Future ground-based and space-borne interferometric gravitational-wave detectors may capture between tens and thousands of binary coalescence events per year. There is a significant and growing body of work on the estimation of astrophysically relevant parameters, such as masses and spins, from the gravitational-wave signature of a single event. This paper introduces a robust Bayesian framework for combining the parameter estimates for multiple events into a parameter distribution of the underlying event population. The framework can be readily deployed as a rapid post-processing tool.
Revisiting the envelope approximation: Gravitational waves from bubble collisions
NASA Astrophysics Data System (ADS)
Weir, David J.
2016-06-01
We study the envelope approximation and its applicability to first-order phase transitions in the early Universe. We demonstrate that the power laws seen in previous studies exist independently of the nucleation rate. We also compare the envelope approximation prediction to results from large-scale phase transition simulations. For phase transitions where the contribution to gravitational waves from scalar fields dominates over that from the coupled plasma of light particles, the envelope approximation is in agreement, giving a power spectrum of the same form and order of magnitude. In all other cases the form and amplitude of the gravitational wave power spectrum is markedly different and new techniques are required.
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.
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. PMID:21599351
Education and public outreach on gravitational-wave astronomy
NASA Astrophysics Data System (ADS)
Hendry, M.; Bradaschia, C.; Audley, H.; Barke, S.; Blair, D. G.; Christensen, N.; Danzmann, K.; Freise, A.; Gerberding, O.; Knispel, B.; Lieser, M.; Mandel, I.; Moore, T.; Stuver, A.; Whiting, B.
2014-08-01
In this paper we summarise the presentations given during the "Education and Public Outreach on Gravitational-Wave Astronomy" parallel session at the GR-20/Amaldi conference, held in Warsaw, July 2013. The talks presented demonstrate the wide range of education and public outreach activities being undertaken in the field of gravitational-wave astronomy—across science festivals, science education centers, junior schools and high schools, colleges and universities, via both face-to-face delivery and (increasingly) the internet and social media.
Preparing for LISA in the Gravitational Wave Era
NASA Astrophysics Data System (ADS)
Larson, Shane
2016-03-01
Before the end of the decade, both LIGO and Pulsar Timing Arrays are expected to make the first detections of gravitational waves, and in all likelihood will have started the compilation of the first gravitational wave catalogs. Both LIGO and Pulsar Timing Arrays observe source populations that radiate in the LISA band at other points in their evolutionary history. In this talk, we'll discuss how early detections of supermassive black hole binaries (by PTAs) and ultra-compact binary mergers (by LIGO) will be important players in understanding the scope of LISA science.
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.
Gravitational waves from periodic three-body systems.
Dmitrašinović, V; Suvakov, Milovan; Hudomal, Ana
2014-09-01
Three bodies moving in a periodic orbit under the influence of Newtonian gravity ought to emit gravitational waves. We have calculated the gravitational radiation quadrupolar waveforms and the corresponding luminosities for the 13+11 recently discovered three-body periodic orbits in Newtonian gravity. These waves clearly allow one to distinguish between their sources: all 13+11 orbits have different waveforms and their luminosities (evaluated at the same orbit energy and body mass) vary by up to 13 orders of magnitude in the mean, and up to 20 orders of magnitude for the peak values. PMID:25238346
Stochastic template placement algorithm for gravitational wave data analysis
Harry, I. W.; Sathyaprakash, B. S.; Allen, B.
2009-11-15
This paper presents an algorithm for constructing matched-filter template banks in an arbitrary parameter space. The method places templates at random, then removes those which are 'too close' together. The properties and optimality of stochastic template banks generated in this manner are investigated for some simple models. The effectiveness of these template banks for gravitational wave searches for binary inspiral waveforms is also examined. The properties of a stochastic template bank are then compared to the deterministically placed template banks that are currently used in gravitational wave data analysis.
Hunting for MHz gravitational waves with the Fermilab Holometer
NASA Astrophysics Data System (ADS)
Kamai, Brittany; The Holometer Collaboration Collaboration
2016-03-01
The highest frequency end of the gravitational wave spectrum remains poorly constrained. Cosmic strings and primordial black holes are potential gravitational waves candidates that could radiate at MHz frequencies. The existence of nearby sources can be tested using the Fermilab Holometer, two nested 40 meter Michelson interferometers. This instrument can achieve strain sensitivity better than 10- 20 / rt .Hz within the 1-10 MHz frequency band. The Holometer is fully operational and has taken long observational campaigns acquiring 100s of hours of science quality data. I will present results of a search for narrow-lined sources and constraints on the stochastic background in the MHz band.
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.
Gravitational waves from periodic three-body systems.
Dmitrašinović, V; Suvakov, Milovan; Hudomal, Ana
2014-09-01
Three bodies moving in a periodic orbit under the influence of Newtonian gravity ought to emit gravitational waves. We have calculated the gravitational radiation quadrupolar waveforms and the corresponding luminosities for the 13+11 recently discovered three-body periodic orbits in Newtonian gravity. These waves clearly allow one to distinguish between their sources: all 13+11 orbits have different waveforms and their luminosities (evaluated at the same orbit energy and body mass) vary by up to 13 orders of magnitude in the mean, and up to 20 orders of magnitude for the peak values.
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.
Fan, Xu; Wang, Yunguang; Cheng, Haiping; Chong, Xiaochen
2016-02-01
The present circuit was designed to apply to human tissue impedance tuning and matching device in ultra-short wave treatment equipment. In order to judge if the optimum status of circuit parameter between energy emitter circuit and accepter circuit is in well syntony, we designed a high frequency envelope detect circuit to coordinate with automatic adjust device of accepter circuit, which would achieve the function of human tissue impedance matching and tuning. Using the sampling coil to receive the signal of amplitude-modulated wave, we compared the voltage signal of envelope detect circuit with electric current of energy emitter circuit. The result of experimental study was that the signal, which was transformed by the envelope detect circuit, was stable and could be recognized by low speed Analog to Digital Converter (ADC) and was proportional to the electric current signal of energy emitter circuit. It could be concluded that the voltage, transformed by envelope detect circuit can mirror the real circuit state of syntony and realize the function of human tissue impedance collecting.
Fan, Xu; Wang, Yunguang; Cheng, Haiping; Chong, Xiaochen
2016-02-01
The present circuit was designed to apply to human tissue impedance tuning and matching device in ultra-short wave treatment equipment. In order to judge if the optimum status of circuit parameter between energy emitter circuit and accepter circuit is in well syntony, we designed a high frequency envelope detect circuit to coordinate with automatic adjust device of accepter circuit, which would achieve the function of human tissue impedance matching and tuning. Using the sampling coil to receive the signal of amplitude-modulated wave, we compared the voltage signal of envelope detect circuit with electric current of energy emitter circuit. The result of experimental study was that the signal, which was transformed by the envelope detect circuit, was stable and could be recognized by low speed Analog to Digital Converter (ADC) and was proportional to the electric current signal of energy emitter circuit. It could be concluded that the voltage, transformed by envelope detect circuit can mirror the real circuit state of syntony and realize the function of human tissue impedance collecting. PMID:27382746
NASA Astrophysics Data System (ADS)
Isobe, H.
2007-12-01
The energy source of coronal heating and solar wind acceleration is the interaction of magnetic field and thermal convection in the photosphere. Magnetoconvection has complicated bifurcation structure, and the mode, spectra and power of the waves generated in the photosphere depend on the nature of magnetoconvection in the photosphere. In order to study the relation between magnetoconvection and coronal heating/solar wind acceleration, we performed three-dimensional magnetohydrodynamic simulation of a domain that includes from upper convection zone to the corona. We first ran the simulation without magnetic field until convection developed to quasi-steady state, and then imposed a vertical and uniform magnetic field. We found that, in addition to the well-known fact that vertical magnetic field is swept into the downflow region, small scale horizontal fields as strong as 800G intermittently emerge in the photosphere. Even though the initial magnetic field is vertical and uniform, magnetic field in the convection zone become turbulent, and occasionally a bundle of strong magnetic flux is driven by the upward convection flow and emerges in the photosphere. Such horizontal fields undergo magnetic reconnection with pre-existing magnetic field in the chromosphere (so called "canopy" field), and then emit high-frequency (>0.05mHz) waves into the corona. We discuss the possible role of these processes in heating, acceleration and turbulence of the corona and the solar wind.
Growing intermediate-mass black holes with gravitational waves
NASA Astrophysics Data System (ADS)
Gultekin, Kayhan
2006-06-01
We present results of numerical simulations of sequences of binary-single scattering events of black holes in dense stellar environments. The simulations cover a wide range of mass ratios from equal mass objects to 1000:10:10 [Special characters omitted.] and compare purely Newtonian simulations with a relativistic endpoint, simulations in which Newtonian encounters are interspersed with gravitational wave emission from the binary, and simulations that include the effects of gravitational radiation reaction by using equations of motion that include the 2.5-order post-Newtonian force terms, which are the leading-order terms of energy loss from gravitational waves. In all cases, the sequence is terminated when the binary's merger time due to gravitational radiation is less than the arrival time of the next interloper. We also examine the role of gravitational waves during an encounter and show that close approach cross-sections for three 1 [Special characters omitted.] objects are unchanged from the purely Newtonian dynamics except for close approaches smaller than 10-5 times the initial semimajor axis of the binary. We also present cross-sections for mergers resulting from gravitational radiation during three-body encounters for a range of binary semimajor axes and mass ratios including those of interest for intermediate-mass black holes (IMBHs). We find that black hole binaries typically merge with a very high eccentricity- --extremely high when gravitational waves are included during the encounter such that when the gravitational waves are detectable by LISA, most of the binaries will have eccentricities e > 0.9 though all will have circularized by the time they are detectable by LIGO. We also investigate the implications for the formation and growth of IMBHs and find that the inclusion of gravitational waves during the encounter results in roughly half as many black holes ejected from the host cluster for each black hole accreted onto the growing IMBH. The
Gravitational waves from binaries on unbound orbits
NASA Astrophysics Data System (ADS)
Majár, János; Forgács, Péter; Vasúth, Mátyás
2010-09-01
A generalized true anomaly-type parametrization, convenient to describe both bound and open orbits of a two-body system in general relativity is introduced. A complete description of the time evolution of both the radial and angular equations of a binary system taking into account the first order post-Newtonian (1PN) corrections is given. The gravitational radiation field emitted by the system is computed in the 1PN approximation including higher multipole moments beyond the standard quadrupole term. The gravitational waveforms in the time domain are explicitly given up to the 1PN order for unbound orbits, but the results are also illustrated on binaries on elliptic orbits with special attention given to the effects of eccentricity.
The Parkes Pulsar Timing Array and detection of gravitational waves
NASA Astrophysics Data System (ADS)
Manchester, R.
Gravitational waves are an important prediction of Einstein s general theory of relativity Evidence for their existence has come from observations of orbit decay in double-neutron-star binary systems but up to now despite huge efforts there has been no direct detection of these waves In collaboration with groups from the Swinburne University of Technology Melbourne and the University of Texas Brownsville we have embarked on a major project to establish the Parkes Pulsar Timing Array PPTA with the principal goal of making a direct detection of gravitational waves of astronomical origin The project involves making precision timing observations of 20 millisecond pulsars at intervals of 2 -- 3 weeks using the Parkes 64-m radio telescope Observations are made at three radio frequencies 685 1400 and 3100 MHz to allow correction for interstellar propagation effects The PPTA is most sensitive to gravitational waves with frequencies in the nanoHertz range and hence is complementary to ground- and space-based laser interferometer systems Simulations suggest that if timing precisions of order 100 nanoseconds can be reached for most of the observed sample over a 5-year data span the stochastic background of gravitational waves from super-massive binary black holes in the cores of galaxies should be detectable Currently we have achieved this level of precision for 3 or 4 pulsars and sub-microsecond precision for a further 8 or 9 pulsars Improved hardware and software systems under development will hopefully allow us to reach our goal The PPTA
Binary Black Holes, Numerical Relativity, and Gravitational Waves
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these wave patterns. For more than 30 years, scientists have tried to compute these wave patterns. However, their computer codes have been plagued by problems that caused them to crash. This situation has changed dramatically in the past 2 years, with a series of amazing breakthroughs. This talk will take you on this quest for these gravitational wave patterns, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will be observed by LISA
Cosmic Messengers: Binary Black Holes and Gravitational Waves
NASA Technical Reports Server (NTRS)
Centrella, Joan
2007-01-01
The final merger of two black holes releases a tremendous amount of energy, more than the combined light from all the stars in the visible universe. This energy is emitted in the form of gravitational waves, and observing these sources with gravitational wave detectors such as LISA requires that we know the pattern or fingerprint of the radiation emitted. Since black hole mergers take place in regions of extreme gravitational fields, we need to solve Einstein s equations of general relativity on a computer in order to calculate these wave patterns. For more than 30 years, scientists have tried to compute these wave patterns. However, their computer codes have been plagued by problems that caused them to crash. . This situation has changed dramatically in the past 2 years, with a series of amazing breakthroughs. This talk will take you on this quest for these gravitational wave patterns, showing how a spacetime is constructed on a computer to build a simulation laboratory for binary black hole mergers. We will focus on the recent advances that are revealing these waveforms, and the dramatic new potential for discoveries that arises when these sources will. be observed by LISA.
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).
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.; Addesso, P.; 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.; Bersanetti, D.; Bertolini, A.; Bessis, D.; Betzwieser, J.; Beyersdorf, P. T.; Bhadbhade, T.; Bilenko, I. A.; Billingsley, G.; Birch, J.; Biscans, S.; 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.; Boschi, V.; 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.; Conte, A.; 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.; Debreczeni, G.; Degallaix, J.; Deleeuw, E.; 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.; Dietz, A.; Di Fiore, L.; Di Lieto, A.; Di Palma, I.; Di Virgilio, 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.; 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.; 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. I.; Jones, D.; Jones, R.; Jonker, R. J. G.; Ju, L.; Haris, K.; 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.; 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, D. Nanda; Kumar, P.; Kumar, R.; Kurdyumov, R.; Kwee, P.; Landry, M.; Lantz, B.; Larson, S.; Lasky, P. D.; Lawrie, C.; Lazzarini, A.; Leaci, P.; Lebigot, E. O.; Lee, C.-H.; Lee, H. K.; Lee, H. M.; Lee, J. J.; Lee, J.; Leonardi, M.; Leong, J. R.; Le Roux, A.; 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.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martini, G.; 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.; 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.; Nardecchia, I.; Nash, T.; Naticchioni, L.; Nayak, R.; Necula, V.; Neri, I.; Neri, M.; 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.; 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.; Poeld, J.; Poggiani, R.; Poole, V.; Postiglione, F.; Poux, C.; Predoi, V.; Prestegard, T.; Price, L. R.; Prijatelj, M.; Privitera, S.; 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.; Sequino, V.; Sergeev, A.; Shaddock, D.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shapiro, B.; Shawhan, P.; Shoemaker, D. H.; Sidery, T. L.; Siellez, K.; Siemens, X.; Sigg, D.; Simakov, D.; Singer, A.; Singer, L.; 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.; Straniero, N.; 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, P. J.; Veitch, J.; Venkateswara, K.; Verkindt, D.; Verma, S.; Vetrano, F.; Viceré, A.; Vincent-Finley, R.; Vinet, J.-Y.; Vitale, S.; 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.; 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.; LIGO Scientific Collaboration; Virgo Collaboration
2015-01-01
Searches for a stochastic gravitational-wave background (SGWB) using terrestrial detectors typically involve cross-correlating data from pairs of detectors. The sensitivity of such cross-correlation analyses depends, among other things, on the separation between the two detectors: the smaller the separation, the better the sensitivity. Hence, a colocated detector pair is more sensitive to a gravitational-wave background than a noncolocated detector pair. However, colocated detectors are also expected to suffer from correlated noise from instrumental and environmental effects that could contaminate the measurement of the background. Hence, methods to identify and mitigate the effects of correlated noise are necessary to achieve the potential increase in sensitivity of colocated detectors. Here we report on the first SGWB analysis using the two LIGO Hanford detectors and address the complications arising from correlated environmental noise. We apply correlated noise identification and mitigation techniques to data taken by the two LIGO Hanford detectors, H1 and H2, during LIGO's fifth science run. At low frequencies, 40-460 Hz, we are unable to sufficiently mitigate the correlated noise to a level where we may confidently measure or bound the stochastic gravitational-wave signal. However, at high frequencies, 460-1000 Hz, these techniques are sufficient to set a 95% confidence level upper limit on the gravitational-wave energy density of Ω (f )<7.7 ×1 0-4(f /900 Hz )3 , which improves on the previous upper limit by a factor of ˜180 . In doing so, we demonstrate techniques that will be useful for future searches using advanced detectors, where correlated noise (e.g., from global magnetic fields) may affect even widely separated detectors.
NASA Technical Reports Server (NTRS)
Aasi, J.; Abadie, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Accadia, T.; Acernese, F.; Adams, C.; Adams, T.; Addesso, P.; 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.; Camp, Jordan B; Gehrels, N.; Kanner, J. B.
2014-01-01
Searches for a stochastic gravitational-wave background (SGWB) using terrestrial detectors typically involve cross-correlating data from pairs of detectors. The sensitivity of such cross-correlation analyses depends, among other things, on the separation between the two detectors: the smaller the separation, the better the sensitivity. Hence, a co-located detector pair is more sensitive to a gravitational-wave background than a nonco- located detector pair. However, co-located detectors are also expected to suffer from correlated noise from instrumental and environmental effects that could contaminate the measurement of the background. Hence, methods to identify and mitigate the effects of correlated noise are necessary to achieve the potential increase in sensitivity of co-located detectors. Here we report on the first SGWB analysis using the two LIGO Hanford detectors and address the complications arising from correlated environmental noise. We apply correlated noise identification and mitigation techniques to data taken by the two LIGO Hanford detectors, H1 and H2, during LIGO's fifth science run. At low frequencies, 40-460Hz, we are unable to sufficiently mitigate the correlated noise to a level where we may confidently measure or bound the stochastic gravitational-wave signal. However, at high frequencies, 460 - 1000Hz, these techniques are sufficient to set a 95% confidence level (C.L.) upper limit on the gravitational-wave energy density of Omega(f) < 7.7 × 10(exp -4)(f/900Hz)(sup 3), which improves on the previous upper limit by a factor of approx. 180. In doing so, we demonstrate techniques that will be useful for future searches using advanced detectors, where correlated noise (e.g., from global magnetic fields) may affect even widely separated detectors.
BOOK REVIEW: Gravitational Waves, Volume 1: Theory and Experiments
NASA Astrophysics Data System (ADS)
Poisson, Eric
2008-10-01
A superficial introduction to gravitational waves can be found in most textbooks on general relativity, but typically, the treatment hardly does justice to a field that has grown tremendously, both in its theoretical and experimental aspects, in the course of the last twenty years. Other than the technical literature, few other sources have been available to the interested reader; exceptions include edited volumes such as [1] and [2], Weber's little book [3] which happily is still in print, and Peter Saulson's text [4] which appears, unfortunately, to be out of print. In addition to these technical references, the story of gravitational waves was famously told by a sociologist of scientific knowledge [5] (focusing mostly on the experimental aspects) and a historian of science [6] (focusing mostly on the theoretical aspects). The book Gravitational Waves, Volume 1, by Michele Maggiore, is a welcome point of departure. This is, as far as I know, the first comprehensive textbook on gravitational waves. It describes the theoretical foundations of the subject, the known (and anticipated) sources, and the principles of detection by resonant masses and laser interferometers. This book is a major accomplishment, and with the promised volume 2 on astrophysical and cosmological aspects of gravitational waves, the community of all scientists interested in this topic will be well served. Part I of the book is devoted to the theoretical aspects of gravitational waves. In chapter 1 the waves are introduced in usual relativist's fashion, in the context of an approximation to general relativity in which they are treated as a small perturbation of the Minkowski metric of flat spacetime. This is an adequate foundation to study how the waves propagate, and how they interact with freely moving masses making up a detector. The waves are presented in the usual traceless-transverse gauge, but the detection aspects are also worked out in the detector's proper rest frame; this dual
Implications of the gravitational wave event GW150914
NASA Astrophysics Data System (ADS)
Miller, M. Coleman
2016-07-01
The era of gravitational-wave astronomy began on 14 September 2015, when the LIGO Scientific Collaboration detected the merger of two ˜30 M_⊙ black holes at a distance of {˜ }400 Mpc. This event has facilitated qualitatively new tests of gravitational theories, and has also produced exciting information about the astrophysical origin of black hole binaries. In this review we discuss the implications of this event for gravitational physics and astrophysics, as well as the expectations for future detections. In brief: (1) because the spins of the black holes could not be measured accurately and because mergers are not well calculated for modified theories of gravity, the current analysis of GW150914 does not place strong constraints on gravity variants that change only the generation of gravitational waves, but (2) it does strongly constrain alterations of the propagation of gravitational waves and alternatives to black holes. Finally, (3) many astrophysical models for the origin of heavy black hole binaries such as the GW150914 system are in play, but a reasonably robust conclusion that was reached even prior to the detection is that the environment of such systems needs to have a relatively low abundance of elements heavier than helium.
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.
Limitations of atom interferometry for gravitational wave observations in space
NASA Astrophysics Data System (ADS)
Bender, Peter L.
2012-03-01
A paper published recently (Hogan et al. in Gen. Relativ. Gravit. 43:1953-2009, 2011) suggests the use of atom interferometry between satellites in Earth orbit to observe gravitational waves. The proposed altitude and satellite separation are about 1,000 and 30 km respectively. The difference in acceleration between clouds of ultracold atoms in atom interferometers near the two satellites would be detected by using laser beams between the interferometers. Because of the measurement path being very short compared with the million km or longer measurement path for a proposed laser interferometer gravitational wave antenna in space, the sensitivity to differential fluctuations in the laser phase as seen by the atoms in the two atom interferometers is very high. Problems introduced by this high sensitivity to spurious laser beam phase changes will be described in the first part of this paper. Then other limitations on the performance and on the suggested types of sources that could be observed will be discussed.
Phasing of gravitational waves from inspiralling eccentric binaries
NASA Astrophysics Data System (ADS)
Damour, Thibault; Gopakumar, Achamveedu; Iyer, Bala R.
2005-05-01
We develop a method for analytically constructing highly accurate post-Newtonian (PN) templates for gravitational-wave signals emitted by compact binaries moving in inspiralling eccentric orbits. Employing an improved 'method of variation of constants', applied to 2PN accurate generalized quasi-Keplerian parametrization for the orbital motion, we combine three relevant time scales associated with the orbital period, periastron precession and radiation reaction, without treating the radiative time scale in an adiabatic manner. We explicitly implement our method to obtain 2.5PN accurate 'post-adiabatic' gravitational waveforms h+,×. Using the 'effective one-body' approach, we define the domain of validity of our method. We also discuss how to extend our method to construct 'ready to use' search templates for gravitational waves from inspiralling eccentric orbits. For a detailed version of this article, see Damour T, Gopakumar A and Iyer B R 2004 Phys. Rev. D 70 064028
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.
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. PMID:21668135
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.
Geodesics in nonexpanding impulsive gravitational waves with Λ, part I
NASA Astrophysics Data System (ADS)
Sämann, Clemens; Steinbauer, Roland; Lecke, Alexander; Podolský, Jiřˇí
2016-06-01
We investigate the geodesics in the entire class of nonexpanding impulsive gravitational waves propagating in an (anti-)de Sitter universe using the distributional form of the metric. Employing a five-dimensional embedding formalism and a general regularisation technique, we prove the existence and uniqueness of the geodesics crossing the wave impulse, leading to a completeness result. We also derive the explicit form of the geodesics, thereby confirming previous results derived in a heuristic approach.
Joint Soviet-American project for detection of gravitational waves
NASA Astrophysics Data System (ADS)
Dubinsky, V.
1984-06-01
A cooperative venture between the U.S.S.R. and the United States on the effects of gravitational waves is discussed. Twenty teams of scientists around the world are designing and building antennas to detect these waves. Two goals are sought: the demonstration of the existence of a qualitatively new structure of matter and a method for obtaining yet inaccessible information on the universe.
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.
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.
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).
Coincidently Searching for Gravitational Waves and Low Frequency Radio Transients
NASA Astrophysics Data System (ADS)
Kavic, Michael; Yancey, C.; Shawhan, P. S.; Cutchin, S.; Simonetti, J. H.; Bear, B.; Tsai, J.
2014-01-01
The transient sky has become an important area of astrophysical study, especially with the appearance of recent fast transients, but little is known about the sources of these transients. One possible approach which can shed light on this area is multi-messenger astronomy using gravitational waves and prompt emission meter-wavelength radio to observe fast transients. This is made possible with gravitational-wave detectors such as LIGO, VIRGO, and GEO (IndIGO and KAGRA proposed or under construction) and phased-array radio-telescopes such LWA, LOFAR, LoFASM, and MWA. This talk presents a method for coincidence of gravitational wave and meter-wavelength radio observations to enable multi-messenger astronomy and discusses the optimization of gravitational-wave and radio sensitivities to attain effective combined observational sensitivities. It is shown that coincidence provides a 52.9% increase to the sensitivity distance for LIGO and a 200% increase to the SNR of radio arrays for particular cases.
Generation of gravitational waves: The post Newtonian spin octupole moment
NASA Astrophysics Data System (ADS)
Damour, T.; Iyer, B. R.
1993-12-01
Using the gravitational wave formalism developed by Blanchet, Damour, and Iyer, this note computes the post-Newtonian-accurate spin octupole moment. The result is checked by explicitly verifying the transformation of the radiative spin octupole moment under shifts of the spatial origin.
Phasing of gravitational waves from inspiralling eccentric binaries
Damour, Thibault; Gopakumar, Achamveedu; Iyer, Bala R.
2004-09-15
We provide a method for analytically constructing high-accuracy templates for the gravitational-wave signals emitted by compact binaries moving in inspiralling eccentric orbits. In contrast to the simpler problem of modeling the gravitational-wave signals emitted by inspiralling circular orbits, which contain only two different time scales, namely, those associated with the orbital motion and the radiation reaction, the case of inspiralling eccentric orbits involves three different time scales: orbital period, periastron precession, and radiation-reaction time scales. By using an improved 'method of variation of constants', we show how to combine these three time scales, without making the usual approximation of treating the radiative time scale as an adiabatic process. We explicitly implement our method at the 2.5PN post-Newtonian accuracy. Our final results can be viewed as computing new 'postadiabatic' short-period contributions to the orbital phasing or, equivalently, new short-period contributions to the gravitational-wave polarizations, h{sub +,x}, that should be explicitly added to the 'post-Newtonian' expansion for h{sub +,x}, if one treats radiative effects on the orbital phasing of the latter in the usual adiabatic approximation. Our results should be of importance both for the LIGO/VIRGO/GEO network of ground based interferometric gravitational-wave detectors (especially if Kozai oscillations turn out to be significant in globular cluster triplets) and for the future space-based interferometer LISA.
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
PREFACE: 8th Edoardo Amaldi Conference on Gravitational Waves
NASA Astrophysics Data System (ADS)
Marka, Zsuzsa; Marka, Szabolcs
2010-04-01
(The attached PDF contains select pictures from the Amaldi8 Conference) At Amaldi7 in Sydney in 2007 the Gravitational Wave International Committee (GWIC), which oversees the Amaldi meetings, decided to hold the 8th Edoardo Amaldi Conference on Gravitational Waves at Columbia University in the City of New York. With this decision, Amaldi returned to North America after a decade. The previous two years have seen many advances in the field of gravitational wave detection. By the summer of 2009 the km-scale ground based interferometric detectors in the US and Europe were preparing for a second long-term scientific run as a worldwide detector network. The advanced or second generation detectors had well-developed plans and were ready for the production phase or started construction. The European-American space mission, LISA Pathfinder, was progressing towards deployment in the foreseeable future and it is expected to pave the ground towards gravitational wave detection in the milliHertz regime with LISA. Plans were developed for an additional gravitational wave detector in Australia and in Japan (in this case underground) to extend the worldwide network of detectors for the advanced detector era. Japanese colleagues also presented plans for a space mission, DECIGO, that would bridge the gap between the LISA and ground-based interferometer frequency range. Compared to previous Amaldi meetings, Amaldi8 had new elements representing emerging trends in the field. For example, with the inclusion of pulsar timing collaborations to the GWIC, gravitational wave detection using pulsar timing arrays was recognized as one of the prominent directions in the field and was represented at Amaldi8 as a separate session. By 2009, searches for gravitational waves based on external triggers received from electromagnetic observations were already producing significant scientific results and plans existed for pointing telescopes by utilizing gravitational wave trigger events. Such
The Center for Gravitational Wave Astronomy at UTB
NASA Astrophysics Data System (ADS)
Diaz, Mario
2013-03-01
In this talk I will succinctly describe the first ten years of research and educational activity at the Center for Gravitational Wave Astronomy at The University of Texas at Brownsville as a potential model for fostering collaborations between minority serving institutions and major research institutions in the USA.
The New Science of Gravitational Waves
NASA Astrophysics Data System (ADS)
Hogan, C. J.
2008-08-01
A brief survey is presented of new science that will emerge during the decades ahead from direct detection of gravitational radiation. Interferometers on earth and in space will probe the universe in an entirely new way by directly sensing motions of distant matter over a range of more than a million in frequency. The most powerful sources of gravitational (or indeed any form of) energy in the universe are inspiraling and merging binary black holes; with Laser Interferometer Space Antenna (LISA) data, they will become the most distant, most completely and precisely modeled, and most accurately measured systems in astronomy outside the solar system. Other sources range from already known and named nearby Galactic binary stars, to compact objects being swallowed by massive black holes, to possible effects of new physics: phase transitions and superstrings from the early universe, or holographic noise from quantum fluctuations of local spacetime. Parts of this survey are based on text prepared by the author for the executive summary of LISA science in the LISA mission's report to the NRC's Beyond Einstein Program Assessment Committee tep{hogan:LISAscience}, where more extensive references can be found. Other reviews and summaries can be found in tet{hogan:flan}, tet{hogan:amsci}, tet{hogan:hughes03}, tet{hogan:hughes06}, tet{ hogan:LISA6}, tet{hogan:thorne}, and tet{hogan:schutz}.
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.
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.
NASA Astrophysics Data System (ADS)
Zhou, M.; Ashour-Abdalla, M.; Berchem, J.; Walker, R. J.; Liang, H.; El-Alaoui, M.; Goldstein, M. L.; Lindqvist, P.-A.; Marklund, G.; Khotyaintsev, Y. V.; Ergun, R. E.; Wilder, F. D.; Russell, C. T.; Strangewway, R. J.; Zhao, C.; Paterson, W. R.; Giles, B. L.; Pollock, C. J.; Torbert, R. B.; Burch, J. L.; Dorelli, J. C.; Gershman, D. J.; Avanov, L. A.; Lavraud, B.; Chandler, M. O.
2016-05-01
We report Magnetospheric Multiscale observations of high-frequency electrostatic waves in the vicinity of the reconnection ion diffusion region on the dayside magnetopause. The ion diffusion region is identified during two magnetopause crossings by the Hall electromagnetic fields, the slippage of ions with respect to the magnetic field, and magnetic energy dissipation. In addition to electron beam modes that have been previously detected at the separatrix on the magnetospheric side of the magnetopause, we report, for the first time, the existence of electron cyclotron harmonic waves at the magnetosheath separatrix. Broadband waves between the electron cyclotron and electron plasma frequencies, which were probably generated by electron beams, were found within the magnetopause current sheet. Contributions by these high-frequency waves to the magnetic energy dissipation were negligible in the diffusion regions as compared to those of lower-frequency waves.
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.
NASA Technical Reports Server (NTRS)
Tinto, Massimo; Armstrong, J. W.
1991-01-01
Massive coalescing binary systems are candidate sources of gravitational radiation in the millihertz frequency band accessible to spacecraft Doppler tracking experiments. This paper discusses signal processing and detection probability for waves from coalescing binaries in the regime where the signal frequency increases linearly with time, i.e., 'chirp' signals. Using known noise statistics, thresholds with given false alarm probabilities are established for one- and two-spacecraft experiments. Given the threshold, the detection probability is calculated as a function of gravitational wave amplitude for both one- and two-spacecraft experiments, assuming random polarization states and under various assumptions about wave directions. This allows quantitative statements about the detection efficiency of these experiments and the utility of coincidence experiments. In particular, coincidence probabilities for two-spacecraft experiments are insensitive to the angle between the directions to the two spacecraft, indicating that near-optical experiments can be done without constraints on spacecraft trajectories.
Maximum gravitational-wave energy emissible in magnetar flares
Corsi, Alessandra; Owen, Benjamin J.
2011-05-15
Recent searches of gravitational-wave data raise the question of what maximum gravitational-wave energies could be emitted during gamma-ray flares of highly magnetized neutron stars (magnetars). The highest energies ({approx}10{sup 49} erg) predicted so far come from a model [K. Ioka, Mon. Not. R. Astron. Soc. 327, 639 (2001), http://adsabs.harvard.edu/abs/2001MNRAS.327..639I] in which the internal magnetic field of a magnetar experiences a global reconfiguration, changing the hydromagnetic equilibrium structure of the star and tapping the gravitational potential energy without changing the magnetic potential energy. The largest energies in this model assume very special conditions, including a large change in moment of inertia (which was observed in at most one flare), a very high internal magnetic field, and a very soft equation of state. Here we show that energies of 10{sup 48}-10{sup 49} erg are possible under more generic conditions by tapping the magnetic energy, and we note that similar energies may also be available through cracking of exotic solid cores. Current observational limits on gravitational waves from magnetar fundamental modes are just reaching these energies and will beat them in the era of advanced interferometers.
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
NASA Astrophysics Data System (ADS)
Danilishin, Stefan L.; Khalili, Farid Ya.
2012-04-01
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.
Probing tensor-vector-scalar theory with gravitational wave asteroseismology
Sotani, Hajime
2009-09-15
In order to examine the gravitational waves emitted from the neutron stars in the tensor-vector-scalar (TeVeS) theory, we derive the perturbation equations for relativistic stars, where for simplicity we omit the perturbations of the vector field. That is, we consider the perturbations of scalar and tensor fields. With this assumption, we find that the axial gravitational waves, which are corresponding to the oscillations of spacetime (w modes), are independent from the perturbations of the scalar field and the effects of the scalar field can be mounted only via the background properties. Using two different equations of state, we calculate the complex eigenfrequencies of axial w modes and find that the dependences of frequencies on the stellar compactness are almost independent from the adopted equation of state and the parameter in TeVeS. Additionally, these dependences of frequencies of axial w modes in TeVeS are obviously different from those expected in general relativity. Thus the direct observations of gravitational waves could reveal the gravitational theory in the strong-field regime.
Periodic gravitational waves from small cosmic string loops
NASA Astrophysics Data System (ADS)
Dubath, Florian; Rocha, Jorge V.
2007-07-01
We consider a population of small, high-velocity cosmic string loops. We assume the typical length of these loops is determined by the gravitational radiation scale and use the results of Polchinski and Rocha which pointed out their highly relativistic nature. A study of the gravitational wave emission from such a population is carried out. The large Lorentz boost involved causes the lowest harmonics of the loops to fall within the frequency band of the Laser Interferometer Gravitational Wave Observatory detector. Because of this feature the gravitational waves emitted by such loops can be detected in a periodic search rather than in burst or stochastic analysis. It is shown that, for interesting values of the string tension (10-10≲Gμ≲10-8), the detector can observe loops at reasonably high redshifts and that detection is, in principle, possible. We compute the number of expected observations produced by such a process. For a 10 h search we find that this number is of order O(10-4). This is a consequence of the low effective number density of the loops traveling along the line of sight. However, small probabilities of reconnection and longer observation times can improve the result.
Simulating Gravitational Wave Emission from Massive Black Hole Binaries
NASA Technical Reports Server (NTRS)
Centrella, Joan
2008-01-01
The final merger of two black holes releases a tremendous amount of energy and is one of the brightest sources in the gravitational wave sky. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. Since these mergers take place in regions of very strong gravitational fields, we need to solve Einstein's equations of general relativity on a computer in order to calculate these waveforms. For more than 30 years, scientists have tried to compute these waveforms using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. In the past few years, this situation has changed dramatically, with a series of amazing breakthroughs. This talk will focus on the recent advances that are revealing these waveforms. highlighting their astrophysical consequences and the dramatic new potential for discovery that arises when merging black holes will be observed using gravitational waves.
NASA Astrophysics Data System (ADS)
Kadinsky-Cade, Katharine; Barazangi, Muawia; Oliver, Jack; Isacks, Bryan
1981-10-01
In this study we investigate crustal and uppermost mantle physical properties that characterize some of the continental plateaus of the Middle East. This is done as part of a larger effort to map and compare high-frequency wave propagation at regional distances across the earth's continental plateaus. Thousands of short-period WWSSN seismograms recorded at stations located in the Middle East and produced by earthquakes with epicentral distances less than about 20° were examined visually in an effort to study lateral variations of high-frequency (0.5-2 Hz) seismic wave propagation across this area, particularly to the north of the zone of continental collision between the Africa-Arabian and Eurasian plates. Variations of frequencies and amplitudes of Sn and Lg relative to P are examined and mapped throughout the region, and this work is supplemented by a study of velocities of Pn, Sn, and Lg. Sn amplitude variations are very striking in this area. An important observation of this study is that Sn propagates efficiently beneath a major part of the Turkish and Iranian plateaus. Sn is strongly attenuated, however, in the northernmost portion of the plateaus south of the Black and Caspian seas and in an area between the two seas. These regions are characterized, in general, by active tectonism, including volcanism, faulting, and folding. However, this active tectonism is not restricted to the areas of high Sn attenuation but appears to extend beneath other parts of the Iranian and Turkish plateaus. Patterns of lateral variations in the propagation of Lg are not as consistent as those for Sn. Lg propagates efficiently across Turkey, Iran, and adjacent regions, but the Lg waves that cross the Turkish and Iranian plateaus are weak and have relatively long predominant periods of about 2-5 s. The Lg phase is not observed when the path of propagation crosses the southern Caspian and the Black seas, consistent with the evidence of oceanic-type crustal structure beneath these
Astronomers Get New Tools for Gravitational-Wave Detection
NASA Astrophysics Data System (ADS)
2010-01-01
Teamwork between gamma-ray and radio astronomers has produced a breakthrough in finding natural cosmic tools needed to make the first direct detections of the long-elusive gravitational waves predicted by Albert Einstein nearly a century ago. An orbiting gamma-ray telescope has pointed radio astronomers to specific locations in the sky where they can discover new millisecond pulsars. Millisecond pulsars, rapidly-spinning superdense neutron stars, can serve as extremely precise and stable natural clocks. Astronomers hope to detect gravitational waves by measuring tiny changes in the pulsars' rotation caused by the passage of the gravitational waves. To do this, they need a multitude of millisecond pulsars dispersed widely throughout the sky. However, nearly three decades after the discovery of the first millisecond pulsar, only about 150 of them had been found, some 90 of those clumped tightly in globular star clusters and thus unusable for detecting gravitational waves. The problem was that millisecond pulsars could only be discovered through arduous, computing-intensive searches of small portions of sky. "We've probably found far less than one percent of the millisecond pulsars in the Milky Way Galaxy," said Scott Ransom of the National Radio Astronomy Observatory (NRAO). The breakthrough came when an instrument aboard NASA's Fermi Gamma-Ray Space Telescope began surveying the sky in 2008. This instrument located hundreds of gamma-ray-emitting objects throughout our Galaxy, and astronomers suspected many of these could be millisecond pulsars. Paul Ray of the Naval Research Laboratory initiated an international collaboration to use radio telescopes to confirm the identity of these objects as millisecond pulsars. "The data from Fermi were like a buried-treasure map," Ransom said. "Using our radio telescopes to study the objects located by Fermi, we found 17 millisecond pulsars in three months. Large-scale searches had taken 10-15 years to find that many," Ransom
Scale-dependent gravitational waves from a rolling axion
NASA Astrophysics Data System (ADS)
Namba, Ryo; Peloso, Marco; Shiraishi, Maresuke; Sorbo, Lorenzo; Unal, Caner
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.
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.
Probing circular polarization in stochastic gravitational wave background with pulsar timing arrays
NASA Astrophysics Data System (ADS)
Kato, Ryo; Soda, Jiro
2016-03-01
We study the detectability of circular polarization in a stochastic gravitational wave background from various sources such as supermassive black hole binaries, cosmic strings, and inflation in the early universe with pulsar timing arrays. We calculate generalized overlap reduction functions for the circularly polarized stochastic gravitational wave background. We find that the circular polarization cannot be detected for an isotropic background. However, there is a chance to observe the circular polarization for an anisotropic gravitational wave background. We also show how to separate polarized gravitational waves from unpolarized gravitational waves.
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}.
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
Testing Modified Gravity with Gravitational-Wave Observations from Space
NASA Astrophysics Data System (ADS)
Sopuerta, Carlos F.; Yunes, Nicolas
The inspiral of stellar compact objects into massive black holes sitting at galactic centers, usually known as extreme-mass-ratio inspirals (EMRIs), is one of the most important sources of gravitational radiation for the future Laser Interferometer Space Antenna (LISA), an ESA-NASA mission. It is expected that LISA will determine the physical parameters of these sources with a high precision. These precise measurements open the possibility of making robust tests of the existence of black holes, of their geometry, and even of the gravitational interaction. In relation to this, intermediate-mass-ratio inspirals (IMRIs) are also of interest to advance ground-based gravitational-wave observatories. In this talk, we discuss how modifications to the gravitational interaction can affect the signals emitted by EMRIs and the detectability of these modifications by LISA. To that end, we present results from an study of a particular modification of General Relativity (GR): Chern-Simons modified gravity, a theory that emerges in different quantum gravitational approaches and where spinning black holes have a geometry different from the Kerr geometry predicted by GR. References: C. F. Sopuerta and N. Yunes "Extreme and Intermediate-Mass Ratio Inspirals in Dynamical Chern-Simons Modified Gravity" Physical Review D80, 064006 (2009). e-Print: arXiv:0904.4501 [gr-qc
Testing Einstein's weak equivalence principle with gravitational waves
NASA Astrophysics Data System (ADS)
Wu, Xue-Feng; Gao, He; Wei, Jun-Jie; Mészáros, Peter; Zhang, Bing; Dai, Zi-Gao; Zhang, Shuang-Nan; Zhu, Zong-Hong
2016-07-01
A conservative constraint on Einstein's weak equivalence principle (WEP) can be obtained under the assumption that the observed time delay between correlated particles from astronomical sources is dominated by the gravitational fields through which they move. Current limits on the WEP are mainly based on the observed time delays of photons with different energies. It is highly desirable to develop more accurate tests that include the gravitational wave (GW) sector. The detection by the advanced LIGO/VIRGO systems of gravitational waves will provide attractive candidates for constraining the WEP, extending the tests to gravitational interactions with potentially higher accuracy. Considering the capabilities of the advanced LIGO/VIRGO network and the source direction uncertainty, we show that the joint detection of GWs and electromagnetic signals could probe the WEP to an accuracy down to 10-10 , which is one order of magnitude tighter than previous limits, and 7 orders of magnitude tighter than the multimessenger (photons and neutrinos) results by supernova 1987A.
The terrestrial gravitational wave environment from known sources
NASA Technical Reports Server (NTRS)
Webbink, Ronald F.
1993-01-01
The objective of this project was to produce a gravitational wave spectral line list of all known binary stars producing expected strain amplitudes at Earth in excess of h = 10 (exp -21), or gravitational wave fluxes in excess of F = 10 (exp -12) erg cm(exp -2) s(exp -1). These strain and flux limits lie above the anticipated detection thresholds for space-borne laser interferometers capable of detecting gravitational radiation in the 10 micron Hz to 1 Hz frequency range. The source list was intended to provide frequency (including each harmonic), amplitude and phase (for each polarization and harmonic), and celestial coordinates for each system, lacking only the orientation of the principal polarization axis with respect to the pole of the coordinate system, and the sign of the source phase and frequency (or, equivalently, of the sense of rotation of the strain tensor with time) from providing a complete source description. Such a spectral line list would lay essential groundwork for high-sensitivity, low-frequency searches for gravitational radiation.
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).
Charge management for gravitational-wave observatories using UV LEDs
NASA Astrophysics Data System (ADS)
Pollack, S. E.; Turner, M. D.; Schlamminger, S.; Hagedorn, C. A.; Gundlach, J. H.
2010-01-01
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 ˜105e/s, as well as spectral measurements of the pendulum charge resulting in a white noise level equivalent to 3×105e/Hz.
White dwarf binaries and the gravitational wave foreground
NASA Astrophysics Data System (ADS)
Benacquista, Matthew
2016-02-01
Galactic white dwarf binaries will be an abundant source of gravitational waves in the mHz frequency band of space-based detectors such as eLISA. A few thousand to a few tens of thousands of these systems will be individually resolvable by eLISA, depending on the final detector configuration. The remaining tens of millions of close white dwarf binaries will create an unresolvable anisotropic foreground of gravitational waves that will be comparable to the instrument noise of eLISA at frequencies below about a mHz. Both the resolvable binaries and the foreground can be used to better understand this population. Careful choice of the initial orientation of eLISA can mitigate this foreground in searches for other sources.
Optimized multilayer dielectric mirror coatings for gravitational wave interferometers
NASA Astrophysics Data System (ADS)
Agresti, Juri; Castaldi, Giuseppe; DeSalvo, Riccardo; Galdi, Vincenzo; Pierro, Vincenzo; Pinto, Innocenzo M.
2006-08-01
The limit sensitivity of interferometric gravitational wave antennas is set by the thermal noise in the dielectric mirror coatings. These are currently made of alternating quarter-wavelength high/low index material layers with low mechanical losses. The quarter-wavelength design yields the maximum reflectivity for a fixed number of layers, but not the lowest noise for a prescribed reflectivity. This motivated our recent investigation of optimal thickness configurations, which guarantee the lowest thermal noise for a targeted reflectivity. This communication provides a compact overview of our results, involving nonperiodic genetically-engineered and truncated periodically-layered configurations. Possible implications for the advanced Laser Interferometer Gravitational wave Observatory (LIGO) are discussed.
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.
Searching for Correlated Radio Transients & Gravitational Wave Bursts
NASA Astrophysics Data System (ADS)
Kavic, Michael; Shawhan, P. S.; Yancey, C.; Cutchin, S.; Simonetti, J. H.; Bear, B.; Tsai, J.
2013-01-01
We will discuss an ongoing multi-messenger search for transient radio pulses and gravitational wave bursts. This work is being conducted jointly by the Long Wavelength Array (LWA) and the LIGO Scientific Collaboration (LSC). A variety of astrophysical sources can produce simultaneous emission of gravitational waves and coherent low-frequency electromagnetic radiation. The primary common source motivating this work is the merger of neutron star binaries for which the LWA and LSC instruments have comparable sensitivity. Additional common sources include supernovae, long timescale GRBs and cosmic string cusp events. Data taken by both instruments can be compared to search for correlated signals. Identification of correlated signals can be used to increase the sensitivity of both instruments. We will summarize the coincident observations which have already been conducted and outline plans for future work. We will describe the process being used for synthesizing these data set and present preliminary results.
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.
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.
Inhomogeneous cosmology. III - Primordial gravitational waves and dust
NASA Technical Reports Server (NTRS)
Adams, P. J.; Hellings, R. W.; Zimmerman, R. L.
1987-01-01
In this paper, the properties of a special class of inhomogeneous cosmological models and the interaction of the inhomogeneities with the evolution of the background geometry and matter are studied. The cosmological model is chosen so that the initial inhomogeneities evolve into 'plane' gravitational waves propagating through a smooth Bianchi I dust background. It is shown how the inhomogeneities interact with matter, 3 K radiation, and the background geometry, causing the expansion to slow down in some regions and speed up in others. It is also shown how the gravitational waves can produce a 'dragging of the inertial frame' which will affect the observed distribution of matter and 3 K radiation. In particular, this frame-dragging effect can account for a major fraction of the obsserved dipole component between the 3 K background radiation and the rest frame of global matter, an effect usually assumed to have been produced by large-scale local motion.
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. PMID:23679702
Breaking strain of neutron star crust and gravitational waves.
Horowitz, C J; Kadau, Kai
2009-05-15
Mountains on rapidly rotating neutron stars efficiently radiate gravitational waves. The maximum possible size of these mountains depends on the breaking strain of the neutron star crust. With multimillion ion molecular dynamics simulations of Coulomb solids representing the crust, we show that the breaking strain of pure single crystals is very large and that impurities, defects, and grain boundaries only modestly reduce the breaking strain to around 0.1. Because of the collective behavior of the ions during failure found in our simulations, the neutron star crust is likely very strong and can support mountains large enough so that their gravitational wave radiation could limit the spin periods of some stars and might be detectable in large-scale interferometers. Furthermore, our microscopic modeling of neutron star crust material can help analyze mechanisms relevant in magnetar giant flares and microflares.
Nonlinear metric perturbation enhancement of primordial gravitational waves.
Bastero-Gil, M; Macias-Pérez, J; Santos, D
2010-08-20
We present the evolution of the full set of Einstein equations during preheating after inflation. We study a generic supersymmetric model of hybrid inflation, integrating fields and metric fluctuations in a 3-dimensional lattice. We take initial conditions consistent with Einstein's constraint equations. The induced preheating of the metric fluctuations is not large enough to backreact onto the fields, but preheating of the scalar modes does affect the evolution of vector and tensor modes. In particular, they do enhance the induced stochastic background of gravitational waves during preheating, giving an energy density in general an order of magnitude larger than that obtained by evolving the tensor fluctuations in an homogeneous background metric. This enhancement can improve the expectations for detection by planned gravitational wave observatories. PMID:20868087
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.
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. PMID:24663746
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.
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.
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.
Distinct family of colliding gravitational waves in general relativity
NASA Astrophysics Data System (ADS)
Halilsoy, Mustafa
1988-11-01
We present a new family of exact solutions for the Einstein equations that describes colliding gravitational shock waves with cross polarization. In the limit of single polarization it reduces to a family that, up to a transformation of its metric functions, is distinct from the well-known Szekeres family. Furthermore, this family of solutions does not belong to the largest family found recently by Ferrari, Iban~ez, and Bruni.
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.
Quark nuggets search using gravitational waves aluminum bar detectors
NASA Astrophysics Data System (ADS)
Ronga, Francesco
2016-07-01
Up to now there is no evidence of supersymmetric WIMPS dark matter. This may suggests to look for more exotic possibilities, for example compact ultra-dense quark nuggets. Nuclearites are an example of compact objects that could be constituent of the dark matter. After a short discussion on nuclearites, the result of a nuclearite search with the gravitational wave bar detectors NAUTILUS and EXPLORER is reported.
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).
Upper limit map of a background of gravitational waves
NASA Astrophysics Data System (ADS)
Abbott, B.; Abbott, R.; Adhikari, R.; Agresti, J.; Ajith, P.; Allen, B.; Amin, R.; Anderson, S. B.; Anderson, W. G.; Arain, M.; Araya, M.; Armandula, H.; Ashley, M.; Aston, S.; Aufmuth, P.; Aulbert, C.; Babak, S.; Ballmer, S.; Bantilan, H.; Barish, B. C.; Barker, C.; Barker, D.; Barr, B.; Barriga, P.; Barton, M. A.; Bayer, K.; Belczynski, K.; Betzwieser, J.; Beyersdorf, P. T.; Bhawal, B.; Bilenko, I. A.; Billingsley, G.; Biswas, R.; Black, E.; Blackburn, K.; Blackburn, L.; Blair, D.; Bland, B.; Bogenstahl, J.; Bogue, L.; Bork, R.; Boschi, V.; Bose, S.; Brady, P. R.; Braginsky, V. B.; Brau, J. E.; Brinkmann, M.; Brooks, A.; Brown, D. A.; Bullington, A.; Bunkowski, A.; Buonanno, A.; Burmeister, O.; Busby, D.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Camp, J. B.; Cannizzo, J.; Cannon, K.; Cantley, C. A.; Cao, J.; Cardenas, L.; Casey, M. M.; Castaldi, G.; Cepeda, C.; Chalkey, E.; Charlton, P.; Chatterji, S.; Chelkowski, S.; Chen, Y.; Chiadini, F.; Chin, D.; Chin, E.; Chow, J.; Christensen, N.; Clark, J.; Cochrane, P.; Cokelaer, T.; Colacino, C. N.; Coldwell, R.; Conte, R.; Cook, D.; Corbitt, T.; Coward, D.; Coyne, D.; Creighton, J. D. E.; Creighton, T. D.; Croce, R. P.; Crooks, D. R. M.; Cruise, A. M.; Cumming, A.; Dalrymple, J.; D'Ambrosio, E.; Danzmann, K.; Davies, G.; Debra, D.; Degallaix, J.; Degree, M.; Demma, T.; Dergachev, V.; Desai, S.; Desalvo, R.; Dhurandhar, S.; Díaz, M.; Dickson, J.; di Credico, A.; Diederichs, G.; Dietz, A.; Doomes, E. E.; Drever, R. W. P.; Dumas, J.-C.; Dupuis, R. J.; Dwyer, J. G.; Ehrens, P.; Espinoza, E.; Etzel, T.; Evans, M.; Evans, T.; Fairhurst, S.; Fan, Y.; Fazi, D.; Fejer, M. M.; Finn, L. S.; Fiumara, V.; Fotopoulos, N.; Franzen, A.; Franzen, K. Y.; Freise, A.; Frey, R.; Fricke, T.; Fritschel, P.; Frolov, V. V.; Fyffe, M.; Galdi, V.; Garofoli, J.; Gholami, I.; Giaime, J. A.; Giampanis, S.; Giardina, K. D.; Goda, K.; Goetz, E.; Goggin, L. M.; González, G.; Gossler, S.; Grant, A.; Gras, S.; Gray, C.; Gray, M.; Greenhalgh, J.; Gretarsson, A. M.; Grosso, R.; Grote, H.; Grunewald, S.; Guenther, M.; Gustafson, R.; Hage, B.; Hammer, D.; Hanna, C.; Hanson, J.; Harms, J.; Harry, G.; Harstad, E.; Hayler, T.; Heefner, J.; Heng, I. S.; Heptonstall, A.; Heurs, M.; Hewitson, M.; Hild, S.; Hirose, E.; Hoak, D.; Hosken, D.; Hough, J.; Howell, E.; Hoyland, D.; Huttner, S. H.; Ingram, D.; Innerhofer, E.; Ito, M.; Itoh, Y.; Ivanov, A.; Jackrel, D.; Johnson, B.; Johnson, W. W.; Jones, D. I.; Jones, G.; Jones, R.; Ju, L.; Kalmus, P.; Kalogera, V.; Kasprzyk, D.; Katsavounidis, E.; Kawabe, K.; Kawamura, S.; Kawazoe, F.; Kells, W.; Keppel, D. G.; Khalili, F. Ya.; Kim, C.; King, P.; Kissel, J. S.; Klimenko, S.; Kokeyama, K.; Kondrashov, V.; Kopparapu, R. K.; Kozak, D.; Krishnan, B.; Kwee, P.; Lam, P. K.; Landry, M.; Lantz, B.; Lazzarini, A.; Lee, B.; Lei, M.; Leiner, J.; Leonhardt, V.; Leonor, I.; Libbrecht, K.; Lindquist, P.; Lockerbie, N. A.; Longo, M.; Lormand, M.; Lubiński, M.; Lück, H.; Machenschalk, B.; Macinnis, M.; Mageswaran, M.; Mailand, K.; Malec, M.; Mandic, V.; Marano, S.; Márka, S.; Markowitz, J.; Maros, E.; Martin, I.; Marx, J. N.; Mason, K.; Matone, L.; Matta, V.; Mavalvala, N.; McCarthy, R.; McClelland, D. E.; McGuire, S. C.; McHugh, M.; McKenzie, K.; McNabb, J. W. C.; McWilliams, S.; Meier, T.; Melissinos, A.; Mendell, G.; Mercer, R. A.; Meshkov, S.; Messaritaki, E.; Messenger, C. J.; Meyers, D.; Mikhailov, E.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Miyakawa, O.; Mohanty, S.; Moreno, G.; Mossavi, K.; Mowlowry, C.; Moylan, A.; Mudge, D.; Mueller, G.; Mukherjee, S.; Müller-Ebhardt, H.; Munch, J.; Murray, P.; Myers, E.; Myers, J.; Newton, G.; Nishizawa, A.; Numata, K.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pan, Y.; Papa, M. A.; Parameshwaraiah, V.; Patel, P.; Pedraza, M.; Penn, S.; Pierro, V.; Pinto, I. M.; Pitkin, M.; Pletsch, H.; Plissi, M. V.; Postiglione, F.; Prix, R.; Quetschke, V.; Raab, F.; Rabeling, D.; Radkins, H.; Rahkola, R.; Rainer, N.; Rakhmanov, M.; Rawlins, K.; Ray-Majumder, S.; Re, V.; Rehbein, H.; Reid, S.; Reitze, D. H.; Ribichini, L.; Riesen, R.; Riles, K.; Rivera, B.; Robertson, N. A.; Robinson, C.; Robinson, E. L.; Roddy, S.; Rodriguez, A.; Rogan, A. M.; Rollins, J.; Romano, J. D.; Romie, J.; Route, R.; Rowan, S.; Rüdiger, A.; Ruet, L.; Russell, P.; Ryan, K.; Sakata, S.; Samidi, M.; Sancho de La Jordana, L.; Sandberg, V.; Sannibale, V.; Saraf, S.; Sarin, P.; Sathyaprakash, B. S.; Sato, S.; Saulson, P. R.; Savage, R.; Savov, P.; Schediwy, S.; Schilling, R.; Schnabel, R.; Schofield, R.; Schutz, B. F.; Schwinberg, P.; Scott, S. M.; Searle, A. C.; Sears, B.; Seifert, F.; Sellers, D.; Sengupta, A. S.; Shawhan, P.; Shoemaker, D. H.; Sibley, A.; Sidles, J. A.; Siemens, X.; Sigg, D.; Sinha, S.; Sintes, A. M.; Slagmolen, B. J. J.; Slutsky, J.; Smith, J. R.; Smith, M. R.; Somiya, K.; Strain, K. A.; Strom, D. M.; Stuver, A.; Summerscales, T. Z.; Sun, K.-X.; Sung, M.; Sutton, P. J.; Takahashi, H.; Tanner, D. B.; Tarallo, M.; Taylor, R.; Taylor, R.; Thacker, J.; Thorne, K. A.; Thorne, K. S.; Thüring, A.; Tokmakov, K. V.; Torres, C.; Torrie, C.; Traylor, G.; Trias, M.; Tyler, W.; Ugolini, D.; Ungarelli, C.; Urbanek, K.; Vahlbruch, H.; Vallisneri, M.; van den Broeck, C.; Varvella, M.; Vass, S.; Vecchio, A.; Veitch, J.; Veitch, P.; Villar, A.; Vorvick, C.; Vyachanin, S. P.; Waldman, S. J.; Wallace, L.; Ward, H.; Ward, R.; Watts, K.; Webber, D.; Weidner, A.; Weinert, M.; Weinstein, A.; Weiss, R.; Wen, S.; Wette, K.; Whelan, J. T.; Whitbeck, D. M.; Whitcomb, S. E.; Whiting, B. F.; Wilkinson, C.; Willems, P. A.; Williams, L.; Willke, B.; Wilmut, I.; Winkler, W.; Wipf, C. C.; Wise, S.; Wiseman, A. G.; Woan, G.; Woods, D.; Wooley, R.; Worden, J.; Wu, W.; Yakushin, I.; Yamamoto, H.; Yan, Z.; Yoshida, S.; Yunes, N.; Zanolin, M.; Zhang, J.; Zhang, L.; Zhao, C.; Zotov, N.; Zucker, M.; Zur Mühlen, H.; Zweizig, J.
2007-10-01
We searched for an anisotropic background of gravitational waves using data from the LIGO S4 science run and a method that is optimized for point sources. This is appropriate if, for example, the gravitational wave background is dominated by a small number of distinct astrophysical sources. No signal was seen. Upper limit maps were produced assuming two different power laws for the source strain power spectrum. For an f-3 power law and using the 50 Hz to 1.8 kHz band the upper limits on the source strain power spectrum vary between 1.2×10-48Hz-1 (100Hz/f)3 and 1.2×10-47Hz-1 (100Hz/f)3, depending on the position in the sky. Similarly, in the case of constant strain power spectrum, the upper limits vary between 8.5×10-49Hz-1 and 6.1×10-48Hz-1. As a side product a limit on an isotropic background of gravitational waves was also obtained. All limits are at the 90% confidence level. Finally, as an application, we focused on the direction of Sco-X1, the brightest low-mass x-ray binary. We compare the upper limit on strain amplitude obtained by this method to expectations based on the x-ray flux from Sco-X1.
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. PMID:25763948
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.
Error Sources for Gravitational Wave Sensors using Atom Interferometry
NASA Astrophysics Data System (ADS)
Bender, Peter L.
2011-04-01
Proposals were made in 2008 for using two atom interferometers with laser links between them as gravitational wave sensors (S. Dimopoulos et al., PRD 78, 122002 (2008)). However, the importance of fluctuations in the laser wavefront aberrations over periods of seconds to minutes was overlooked in these proposals. For the AGIS-Sat 3 proposal, the total path length would be 10,000 km, and the laser wavefront aberration fluctuations would have to be attenuated to a level of 2 × 10-9 wavelengths in order to achieve the quoted gravitational wave sensitivity. For the AGIS-Sat 2 proposal, the requirement would be a factor 10 less severe. In addition, the atom cloud temperature fluctuations from cloud to cloud would have to be less than 0.2 pK and 2 pK for the two proposed missions. More recently, a proposal for a gravitational wave mission called AGIS-LEO at 1000 km altitude in Earth orbit has been made (J. M. Hogan et al., arXiv:1009.2702v1, 14 Sept. 2010). For this mission, the atom interferometer separation would be 30 km, and the wavefront aberration jitter would need to be reduced to 2 × 10-8 wavelengths. Some steps toward mitigation of the wavefront aberration jitter problem are mentioned, including possible use of an extra initial laser propagation path and a mode-scrubbing cavity. However, the requirements on such filtering systems appear to be severe.
Gravitational Wave Astronomy: Opening a New Window on the Universe
NASA Astrophysics Data System (ADS)
Hendry, Martin A.
2015-08-01
As we mark the centenary of Einstein's General Theory of Relativity, a new era of observational astronomy is about to begin with the upcoming first science runs of a global network of second generation, ground-based laser interferometric gravitational wave detectors.In this talk I will briefly review the history of the field, and the scientific results achieved to date by the LIGO and Virgo detectors, before describing the significant technological developments that mark the transition from initial LIGO and Virgo to their advanced counterparts. I will then outline the path towards the first direct detections of gravitational wave sources - expected to occur within the next few years - highlighting the astrophysical nature of the sources, current best estimates for their detection rates, the analysis methods that will be employed and the opportunities and strategies for identifying counterparts across the E-M spectrum. Finally I will describe some of the key science questions - in astrophysics, fundamental physics and cosmology - that future gravitational wave observations may address.
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.
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.
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.
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.
Possibility of observable amount of gravitational waves from inflation.
Pilo, L; Riotto, A; Zaffaroni, A
2004-05-21
The curvaton and inhomogeneous reheating scenarios for the generation of the cosmological curvature perturbation on large scales represent an alternative to the standard slow-roll scenario. The basic assumption of these mechanisms is that the initial curvature perturbation due to the inflaton field is negligible. This is usually attained by lowering the energy scale of inflation, thereby concluding that the amount of gravitational waves produced during inflation is highly suppressed. We show that the curvaton and inhomogeneous reheating scenarios are compatible with a level of gravity-wave fluctuations which may well be observed in future satellite experiments.
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.
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.
Massive to gauge field reduction and gravitational wave zone information
NASA Astrophysics Data System (ADS)
Deser, S.
2016-07-01
I analyze the possible relevance of LIGO's gravitational wave detection to the viability of massive gravity models. In GR, a wave zone, where the linearized approximation holds, is guaranteed to exist and the observed wave's amplitude profile can be sufficiently related to the emitting strong field interior to verify that, in this case, it was due to an inspiraling black hole merger. After an excursion to massive spin 1's massless limit, linear massive tensor theory is shown explicitly to propagate only (retarded) maximal, helicity 2, modes to O( m) as m→ 0; however, we don't know if the full theory has a similar "wave zone" governed by the linear model. Even if it does, a much more serious obstacle for massive gravity is to construct a time-varying strong field event to compare with the strong field footprint of LIGO's observed signals.
Testing General Relativity with Low-Frequency, Space-Based Gravitational-Wave Detectors
NASA Astrophysics Data System (ADS)
Gair, Jonathan R.; Vallisneri, Michele; Larson, Shane L.; Baker, John G.
2013-09-01
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.
NASA Technical Reports Server (NTRS)
Peng, Huei; Torr, Douglas G.
1990-01-01
This paper investigates the effect of gravitational waves on a superconductor. It is found that the key properties of a superconductor, namely zero resistance and perfect diamagnetism, give rise to an important new effect, the presence of an induced electric field E in the interior of the superconductor. The E field reacts with the ions and superelectrons. It is argued that the induced E field might provide a significantly more sensitive means of detecting gravitational waves. It appears likely that existing resonant-mass superconducting antennas with L about 3m, Q about 10 to the 8th could be readily modified to detect E fields induced by GWs of dimensionless amplitude h about 10 to the -24th.
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
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
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
Gravitational waves from first order phase transitions during inflation
Chialva, Diego
2011-01-15
We study the production, spectrum, and detectability of gravitational waves in models of the early Universe where first order phase transitions occur during inflation. We consider all relevant sources. The self-consistency of the scenario strongly affects the features of the waves. The spectrum appears to be mainly sourced by collisions of bubble of the new phases, while plasma dynamics (turbulence) and the primordial gauge fields connected to the physics of the transitions are generally subdominant. The amplitude and frequency dependence of the spectrum for modes that exit the horizon during inflation are different from those of the waves produced by quantum vacuum oscillations of the metric or by first order phase transitions not occurring during inflation. A not too large number of slow (but still successful) phase transitions can leave detectable marks in the common microwave background radiation, but the signal weakens rapidly for faster transitions. When the number of phase transitions is instead large, the primordial gravitational waves can be observed both in the common microwave background radiation or with LISA (but in this case only marginally, for the slowest transitions) and especially with DECIGO. We also discuss the nucleosynthesis bound and the constraints it places on the parameters of the models.
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.
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
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 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
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.
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.
NASA Astrophysics Data System (ADS)
Tanimoto, T.; Okamoto, T.
2013-12-01
Modeling high-frequency (>1 Hz) seismic waves is known to be difficult but it is extremely important for earthquake hazard mitigation as many buildings have resonant frequencies above 1 Hz. In this study, we examine high-frequency waves at 1.64 Hz, generated by building-shaking experiments in California. The specific data we will examine are seismic data generated by shaking experiments of the Millikan Library between 2000 and 2002, located on the campus of California Institute of Technology in Pasadena, California. The excited wavefields were recorded by the broadband seismic network in the region (~150 stations), Southern California Seismic Network (SCSN). There were about 60 stations with good signal-to-noise ratios among SCSN stations. The maximum distance for signal detection was 323 km (station GRA). Based on numerical calculations for a regional seismic structure model (SCEC Community Velocity Model 11.9), we can show that the signals are dominated by surface waves (at 1.11 Hz and 1.64 Hz), whose energy is confined to shallow depths. The focus of this report will be on the cross-correlated signals between a station in the building (station MIK) and other stations. This cross-correlation may be viewed as a source deconvolution process and will let us focus on propagation in the medium. This cross-correlated phase can be expressed as a line integral of wavenumber along a propagation path for a direct (ballistic) phase, although it may contain complexity from the caustics (the Maslov index). Somewhat to our surprise, despite the fact that we are dealing with high frequency waves (1.64 Hz), we observe well-defined constant phase in many cross-correlated seismograms. If we knew the number of cycles between the source (Millikan) and a station, we could estimate phase velocity in principle but this is not possible and seems extremely hard because the number of cycles is about 50-100 or more. However, our signals do show frequency-dependence within a narrow (signal
Implementation of barycentric resampling for continuous wave searches in gravitational wave data
Patel, Pinkesh; Dupuis, Rejean; Betzwieser, Joseph; Siemens, Xavier
2010-04-15
We describe an efficient implementation of a coherent statistic for searches of continuous gravitational wave from neutron stars. The algorithm works by transforming the data taken by a gravitational wave detector from a moving Earth bound frame to one that sits at the Solar System barycenter. Many practical difficulties arise in the implementation of this algorithm, some of which have not been discussed previously. These difficulties include constraints of small computer memory, discreteness of the data, losses due to interpolation, and gaps in real data. This implementation is considerably more efficient than previous implementations of these kinds of searches on Laser Interferometer Gravitational Wave (LIGO) detector data. The speed-up factors range from 10, when applied to Einstein-Home, to about 2000 for targeted searches which integrate over months of data.
Gapeev, A B; Rubanik, A V; Pashovkin, T N; Chemeris, N K
2007-01-01
The capability of high peak-power pulsed electromagnetic radiation of extremely high frequency (35,27 GHz, pulse widths of 100 and 600 ns, peak power of 20 kW) to excite acoustic waves in model water-containing objects and muscular tissue of animals has been experimentally shown for the first time. The amplitude and duration of excited acoustic pulses are within the limits of accuracy of theoretical assessments and have a complex nonlinear dependence on the energy input of electromagnetic radiation supplied. The velocity of propagation of acoustic pulses in water-containing models and isolated muscular tissue of animals was close to the reference data. The excitation of acoustic waves in biological systems under the action of high peak-power pulsed electromagnetic radiation of extremely high frequency is the important phenomenon, which essentially contributes to the understanding of the mechanisms of biological effects of these electromagnetic fields.
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. PMID:26371635
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.
A lunar gravitational wave antenna using a laser interferometer
NASA Astrophysics Data System (ADS)
Stebbins, R. T.; Bender, P. L.
1990-03-01
A moon-based laser interferometer for detecting gravitational radiation could detect signals in the band 0.1 - 10,000 Hz. A preliminary evaluation of the noise budget for an optimistic antenna design is reported here and compared to that for other planned gravitational wave interferometers. Over most of the frequency range, the sensitivity is controlled by the thermal noise in the test mass suspensions. From roughly 3 to a few hundred Hertz, it is about the same as the sensitivity expected in terrestrial antennas of the same construction, which will have been operating for at least a decade. Below 0.3 Hz, a proposed space-based interferometer, designed for operation down to 10 exp -5 Hz, would have better sensitivity.
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. PMID:23003237
Low-frequency terrestrial gravitational-wave detectors
NASA Astrophysics Data System (ADS)
Harms, Jan; Slagmolen, Bram J. J.; Adhikari, Rana X.; Miller, M. Coleman; Evans, Matthew; Chen, Yanbei; Müller, Holger; Ando, Masaki
2013-12-01
Direct detection of gravitational radiation in the audio band is being pursued with a network of kilometer-scale interferometers (LIGO, Virgo, KAGRA). Several space missions (LISA, DECIGO, BBO) have been proposed to search for sub-hertz radiation from massive astrophysical sources. Here we examine the potential sensitivity of three ground-based detector concepts aimed at radiation in the 0.1-10 Hz band. We describe the plethora of potential astrophysical sources in this band and make estimates for their event rates and thereby, the sensitivity requirements for these detectors. The scientific payoff from measuring astrophysical gravitational waves in this frequency band is great. Although we find no fundamental limits to the detector sensitivity in this band, the remaining technical limits will be extremely challenging to overcome.
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.
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.
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.
Detection methods for non-Gaussian gravitational wave stochastic backgrounds
NASA Astrophysics Data System (ADS)
Drasco, Steve; Flanagan, Éanna É.
2003-04-01
A gravitational wave stochastic background can be produced by a collection of independent gravitational wave events. There are two classes of such backgrounds, one for which the ratio of the average time between events to the average duration of an event is small (i.e., many events are on at once), and one for which the ratio is large. In the first case the signal is continuous, sounds something like a constant hiss, and has a Gaussian probability distribution. In the second case, the discontinuous or intermittent signal sounds something like popcorn popping, and is described by a non-Gaussian probability distribution. In this paper we address the issue of finding an optimal detection method for such a non-Gaussian background. As a first step, we examine the idealized situation in which the event durations are short compared to the detector sampling time, so that the time structure of the events cannot be resolved, and we assume white, Gaussian noise in two collocated, aligned detectors. For this situation we derive an appropriate version of the maximum likelihood detection statistic. We compare the performance of this statistic to that of the standard cross-correlation statistic both analytically and with Monte Carlo simulations. In general the maximum likelihood statistic performs better than the cross-correlation statistic when the stochastic background is sufficiently non-Gaussian, resulting in a gain factor in the minimum gravitational-wave energy density necessary for detection. This gain factor ranges roughly between 1 and 3, depending on the duty cycle of the background, for realistic observing times and signal strengths for both ground and space based detectors. The computational cost of the statistic, although significantly greater than that of the cross-correlation statistic, is not unreasonable. Before the statistic can be used in practice with real detector data, further work is required to generalize our analysis to accommodate separated, misaligned
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 Waves from Coalescing Binary Black Holes: Theoretical and Experimental Challenges
2010-04-29
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, ...).
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.
Physics and Astronomy with Sources of Gravitational Waves
NASA Astrophysics Data System (ADS)
Phinney, S.
Over the next decade, astrophysical sources of gravitational waves will almost certainly be detected at frequencies ranging from 10-17Hz to 1 kHz, by ground-based interferometers (e.g.GEO-600, LIGO, VIRGO), by the NASA/ESA Laser Interferometer Space Antenna (LISA) mission planned for launch in 2012, by timing of millisecond pulsars, and by measurements of the polarisation of the cosmic microwave background. We describe the nature of the likely sources, and the impact their detection will have on our understanding of relativity, cosmology and a wide range of astrophysical phenomena.
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.
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.
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. PMID:26252674
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.
Mirror thermal noise in interferometric gravitational wave detectors
NASA Astrophysics Data System (ADS)
Rao, Shanti Raja
2003-12-01
The LIGO (Laser Interferometer Gravitational-wave Observatory) project has begun its search for gravitational waves, and efforts are being made to improve its ability to detect these. The LIGO observatories are long, Fabry-Perot-Michelson interferometers, where the interferometer mirrors are also the gravitational wave test masses. LIGO is designed to detect the ripples in spacetime caused by cataclysmic astrophysical events, with a target gravitational wave minimum strain sensitivity of 4 × 10-22 [7] around 100 Hz. The Advanced LIGO concept [57] calls for an order of magnitude improvement in strain sensitivity, with a better signal to noise ratio to increase the rate of detection of events. Some of Advanced LIGO's major requirements are improvements over the LIGO design for thermal noise in the test mass substrates and reflective coatings [57]. Thermal noise in the interferometer mirrors is a significant challenge in LIGO's development. This thesis reviews the theory of test mass thermal noise and reports on several experiments conducted to understand this theory. Experiments to measure the thermal expansion of mirror substrates and coatings use the photothermal effect in a cross-polarized Fabry-Perot interferometer, with displacement sensitivity of 10-15m/rHz. Data are presented from 10 Hz to 4 kHz on solid aluminum, and on sapphire, BK7, and fused silica, with and without commercial TiO2/SiO2 dielectric mirror coatings. The substrate contribution to thermal expansion is compared to theories by Cerdonio et al. [32] and Braginsky, Vyatchanin, and Gorodetsky [22]. New theoretical models are presented for estimating the coating contribution to the thermal expansion. These results can also provide insight into how heat flows between coatings and substrates relevant to predicting coating thermoelastic noise [26, 108]. The Thermal Noise Interferometer (TNI) project is a interferometer built specifically to study thermal noise, and this thesis describes its
Propagating speed of primordial gravitational waves and inflation
NASA Astrophysics Data System (ADS)
Cai, Yong; Wang, Yu-Tong; Piao, Yun-Song
2016-08-01
We show that if the propagating speed of gravitational waves (GWs) gradually diminishes during inflation, the power spectrum of primordial GWs will be strongly blue, while that of the primordial scalar perturbation may be unaffected. We also illustrate that such a scenario is actually a disformal dual to the superinflation, but it does not have the ghost instability. The blue tilt obtained is 0
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.
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.
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.