Maximum Redshift of Gravitational Wave Merger Events
Koushiappas, Savvas M.; Loeb, Abraham
2017-12-01
Future generations of gravitational wave detectors will have the sensitivity to detect gravitational wave events at redshifts far beyond any detectable electromagnetic sources. We show that if the observed event rate is greater than one event per year at redshifts z ≥40 , then the probability distribution of primordial density fluctuations must be significantly non-Gaussian or the events originate from primordial black holes. The nature of the excess events can be determined from the redshift distribution of the merger rate.
INTEGRAL Upper Limits on Gamma-Ray Emission Associated with the Gravitational Wave Event GW150914
DEFF Research Database (Denmark)
Savchenko, V.; Ferrigno, C.; Mereghetti, S.
2016-01-01
Using observations of the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), we place upper limits on the gamma-ray and hard X-ray prompt emission associated with the gravitational wave event GW150914, which was discovered by the LIGO/Virgo Collaboration. The omnidirectional view...... in the 75 keV-2 MeV energy range for typical spectral models. Our results constrain the ratio of the energy promptly released in gamma-rays in the direction of the observer to the gravitational wave energy Eγ/EGW ... of the gravitational wave source, based on the available predictions for prompt electromagnetic emission....
INTEGRAL Upper Limits on Gamma-Ray Emission Associated with the Gravitational Wave Event GW150914
DEFF Research Database (Denmark)
Savchenko, V.; Ferrigno, C.; Natalucci, L.
Using observations of the INTErnational Gamma-Ray Astrophysics Laboratory (INTEGRAL), we place upper limits on the gamma-ray and hard X-ray prompt emission associated with the gravitational wave event GW150914, discovered by the LIGO/Virgo Collaboration. The omnidirectional view of the INTEGRAL...... MeV energy range for typical spectral models. Our results constrain the ratio of the energy promptly released in gamma-rays in the direction of the observer to the gravitational wave energy Eγ/EGW gravitational wave...
Streamlining Collaboration for the Gravitational-wave Astronomy Community
Koranda, S.
2016-12-01
In the morning hours of September 14, 2015 the LaserInterferometer Gravitational-wave Observatory (LIGO) directlydetected gravitational waves from inspiraling and coalescingblack holes, confirming a major prediction of AlbertEinstein's general theory of relativity and beginning the eraof gravitational-wave astronomy. With the LIGO detectors in the United States, the Virgo andGEO detectors in Europe, and the KAGRA detector in Japan thegravitational-wave astrononmy community is opening a newwindow on our Universe. Realizing the full science potentialof LIGO and the other interferometers requires globalcollaboration not only within the gravitational-wave astronomycommunity but also with the astronomers and astrophysicists acrossmultipe disciplines working to realize and leverage the powerof multi-messenger astronomy. Enabling thousands of researchers from around the world andacross multiple projects to efficiently collaborate, share,and analyze data and provide streamlined access to services,computing, and tools requires new and scalable approaches toidentity and access management (IAM). We will discuss LIGO'sIAM journey that began in 2007 and how today LIGO leveragesinternal identity federations like InCommon and eduGAIN toprovide scalable and managed access for the gravitational-waveastronomy community. We will discuss the steps both largeand small research organizations and projects take as theirIAM infrastructure matures from ad-hoc silos of independent services to fully integrated and federated services thatstreamline collaboration so that scientists can focus onresearch and not managing passwords.
GRAVITATIONAL MICROLENSING EVENTS AS A TARGET FOR THE SETI PROJECT
Energy Technology Data Exchange (ETDEWEB)
Rahvar, Sohrab, E-mail: rahvar@sharif.edu [Department of Physics, Sharif University of Technology, P.O. Box 11365–9161, Tehran (Iran, Islamic Republic of)
2016-09-01
The detection of signals from a possible extrasolar technological civilization is one of the most challenging efforts of science. In this work, we propose using natural telescopes made of single or binary gravitational lensing systems to magnify leakage of electromagnetic signals from a remote planet that harbors Extraterrestrial Intelligent (ETI) technology. Currently, gravitational microlensing surveys are monitoring a large area of the Galactic bulge to search for microlensing events, finding more than 2000 events per year. These lenses are capable of playing the role of natural telescopes, and, in some instances, they can magnify radio band signals from planets orbiting around the source stars in gravitational microlensing systems. Assuming that the frequency of electromagnetic waves used for telecommunication in ETIs is similar to ours, we propose follow-up observation of microlensing events with radio telescopes such as the Square Kilometre Array (SKA), the Low Frequency Demonstrators, and the Mileura Wide-Field Array. Amplifying signals from the leakage of broadcasting by an Earth-like civilization will allow us to detect them as far as the center of the Milky Way galaxy. Our analysis shows that in binary microlensing systems, the probability of amplification of signals from ETIs is more than that in single microlensing events. Finally, we propose the use of the target of opportunity mode for follow-up observations of binary microlensing events with SKA as a new observational program for searching ETIs. Using optimistic values for the factors of the Drake equation provides detection of about one event per year.
A Spectroscopic and Photometric Study of Gravitational Microlensing Events
Kane, Stephen R.
2000-08-01
Gravitational microlensing has generated a great deal of scientific interest over recent years. This has been largely due to the realization of its wide-reaching applications, such as the search for dark matter, the detection of planets, and the study of Galactic structure. A significant observational advance has been that most microlensing events can be identified in real-time while the source is still being lensed. More than 400 microlensing events have now been detected towards the Galactic bulge and Magellanic Clouds by the microlensing survey teams EROS, MACHO, OGLE, DUO, and MOA. The real-time detection of these events allows detailed follow-up observations with much denser sampling, both photometrically and spectroscopically. The research undertaken in this project on photometric studies of gravitational microlensing events has been performed as a member of the PLANET (Probing Lensing Anomalies NETwork) collaboration. This is a worldwide collaboration formed in the early part of 1995 to study microlensing anomalies - departures from an achromatic point source, point lens light curve - through rapidly-sampled, multi-band, photometry. PLANET has demonstrated that it can achieve 1% photometry under ideal circumstances, making PLANET observations sensitive to detection of Earth-mass planets which require characterization of 1%--2% deviations from a standard microlensing light curve. The photometric work in this project involved over 5 months using the 1.0 m telescope at Canopus Observatory in Australia, and 3 separate observing runs using the 0.9 m telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. Methods were developed to reduce the vast amount of photometric data using the image analysis software MIDAS and the photometry package DoPHOT. Modelling routines were then written to analyse a selection of the resulting light curves in order to detect any deviation from an achromatic point source - point lens light curve. The photometric
Díaz, M. C.; Macri, L. M.; Garcia Lambas, D.; Mendes de Oliveira, C.; Nilo Castellón, J. L.; Ribeiro, T.; Sánchez, B.; Schoenell, W.; Abramo, L. R.; Akras, S.; Alcaniz, J. S.; Artola, R.; Beroiz, M.; Bonoli, S.; Cabral, J.; Camuccio, R.; Castillo, M.; Chavushyan, V.; Coelho, P.; Colazo, C.; Costa-Duarte, M. V.; Cuevas Larenas, H.; DePoy, D. L.; Domínguez Romero, M.; Dultzin, D.; Fernández, D.; García, J.; Girardini, C.; Gonçalves, D. R.; Gonçalves, T. S.; Gurovich, S.; Jiménez-Teja, Y.; Kanaan, A.; Lares, M.; Lopes de Oliveira, R.; López-Cruz, O.; Marshall, J. L.; Melia, R.; Molino, A.; Padilla, N.; Peñuela, T.; Placco, V. M.; Quiñones, C.; Ramírez Rivera, A.; Renzi, V.; Riguccini, L.; Ríos-López, E.; Rodriguez, H.; Sampedro, L.; Schneiter, M.; Sodré, L.; Starck, M.; Torres-Flores, S.; Tornatore, M.; Zadrożny, A.
2017-10-01
We present the results of prompt optical follow-up of the electromagnetic counterpart of the gravitational-wave event GW170817 by the Transient Optical Robotic Observatory of the South Collaboration. We detected highly significant dimming in the light curves of the counterpart ({{Δ }}g=0.17+/- 0.03 mag, {{Δ }}r=0.14+/- 0.02 mag, {{Δ }}I=0.10+/- 0.03 mag) over the course of only 80 minutes of observations obtained ˜35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ˜59 hr after the event with the EABA 1.5 m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a “blue kilonova” relatively free of lanthanides.
AGILE OBSERVATIONS OF THE GRAVITATIONAL-WAVE EVENT GW150914
Energy Technology Data Exchange (ETDEWEB)
Tavani, M.; Donnarumma, I.; Argan, A.; Monte, E. Del; Evangelista, Y.; Piano, G.; Munar-Adrover, P. [INAF-IAPS, via del Fosso del Cavaliere 100, I-00133 Roma (Italy); Pittori, C.; Verrecchia, F.; Lucarelli, F.; Antonelli, L. A. [ASI Science Data Center (ASDC), Via del Politecnico, I-00133 Roma (Italy); Bulgarelli, A.; Marisaldi, M.; Fioretti, V.; Zoli, A. [INAF-IASF-Bologna, Via Gobetti 101, I-40129 Bologna (Italy); Giuliani, A.; Caraveo, P. [INAF-IASF Milano, via E.Bassini 15, I-20133 Milano (Italy); Trois, A. [INAF, Osservatorio Astronomico di Cagliari, Poggio dei Pini, strada 54, I-09012 Capoterra (Italy); Barbiellini, G. [Dip. di Fisica, Universita’ di Trieste and INFN, Via Valerio 2, I-34127 Trieste (Italy); Cattaneo, P. W., E-mail: victor@roma2.infn.it.it [INFN-Pavia, Via Bassi 6, I-27100 Pavia (Italy); and others
2016-07-01
We report the results of an extensive search through the AGILE data for a gamma-ray counterpart to the LIGO gravitational-wave (GW) event GW150914. Currently in spinning mode, AGILE has the potential of cover 80% of the sky with its gamma-ray instrument, more than 100 times a day. It turns out that AGILE came within a minute of the event time of observing the accessible GW150914 localization region. Interestingly, the gamma-ray detector exposed ∼65% of this region during the 100 s time intervals centered at −100 and +300 s from the event time. We determine a 2 σ flux upper limit in the band 50 MeV–10 GeV, UL = 1.9 × 10{sup −8} erg cm{sup −2} s{sup −1}, obtained ∼300 s after the event. The timing of this measurement is the fastest ever obtained for GW150914, and significantly constrains the electromagnetic emission of a possible high-energy counterpart. We also carried out a search for a gamma-ray precursor and delayed emission over five timescales ranging from minutes to days: in particular, we obtained an optimal exposure during the interval −150/−30 s. In all these observations, we do not detect a significant signal associated with GW150914. We do not reveal the weak transient source reported by Fermi -GBM 0.4 s after the event time. However, even though a gamma-ray counterpart of the GW150914 event was not detected, the prospects for future AGILE observations of GW sources are decidedly promising.
Optimal detection of burst events in gravitational wave interferometric observatories
International Nuclear Information System (INIS)
Vicere, Andrea
2002-01-01
We consider the problem of detecting a burst signal of unknown shape in the data from gravitational wave interferometric detectors. We introduce a statistic which generalizes the excess power statistic proposed first by Flanagan and Hughes, and then extended by Anderson et al. to the multiple detector case. The statistic that we propose is shown to be optimal for an arbitrary noise spectral characteristic, under the two hypotheses that the noise is Gaussian, albeit colored, and that the prior for the signal is uniform. The statistic derivation is based on the assumption that a signal affects only N parallel samples in the data stream, but that no other information is a priori available, and that the value of the signal at each sample can be arbitrary. This is the main difference from previous works, where different assumptions were made, such as a signal distribution uniform with respect to the metric induced by the (inverse) noise correlation matrix. The two choices are equivalent if the noise is white, and in that limit the two statistics do indeed coincide. In the general case, we believe that the statistic we propose may be more appropriate, because it does not reflect the characteristics of the noise affecting the detector on the supposed distribution of the gravitational wave signal. Moreover, we show that the proposed statistic can be easily implemented in its exact form, combining standard time-series analysis tools which can be efficiently implemented. We generalize this version of an excess power statistic to the multiple detector case, considering first a noise uncorrelated among the different instruments, and then including the effect of correlated noise. We discuss exact and approximate forms of the statistic; the choice depends on the characteristics of the noise and on the assumed length of the burst event. As an example, we show the sensitivity of the network of interferometers to a δ-function burst
Gravitational black hole hair from event horizon supertranslations
Energy Technology Data Exchange (ETDEWEB)
Averin, Artem [Arnold-Sommerfeld-Center for Theoretical Physics,Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut,80805 München (Germany); Dvali, Gia [Arnold-Sommerfeld-Center for Theoretical Physics,Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut,80805 München (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University,4 Washington Place, New York, NY 10003 (United States); Gomez, Cesar [Instituto de Física Teórica UAM-CSIC, C-XVI, Universidad Autónoma de Madrid,Cantoblanco, 28049 Madrid (Spain); Lüst, Dieter [Arnold-Sommerfeld-Center for Theoretical Physics,Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut,80805 München (Germany)
2016-06-16
We discuss BMS supertranslations both at null-infinity BMS{sup −} and on the horizon BMS{sup H} for the case of the Schwarzschild black hole. We show that both kinds of supertranslations lead to infinetly many gapless physical excitations. On this basis we construct a quotient algebra A≡BMS{sup H}/BMS{sup −} using suited superpositions of both kinds of transformations which cannot be compensated by an ordinary BMS-supertranslation and therefore are intrinsically due to the presence of an event horizon. We show that transformations in A are physical and generate gapless excitations on the horizon that can account for the gravitational hair as well as for the black hole entropy. We identify the physics of these modes as associated with Bogolioubov-Goldstone modes due to quantum criticality. Classically the number of these gapless modes is infinite. However, we show that due to quantum criticality the actual amount of information-carriers becomes finite and consistent with Bekenstein entropy. Although we only consider the case of Schwarzschild geometry, the arguments are extendable to arbitrary space-times containing event horizons.
Gravitational black hole hair from event horizon supertranslations
International Nuclear Information System (INIS)
Averin, Artem; Dvali, Gia; Gomez, Cesar; Lüst, Dieter
2016-01-01
We discuss BMS supertranslations both at null-infinity BMS"− and on the horizon BMS"H for the case of the Schwarzschild black hole. We show that both kinds of supertranslations lead to infinetly many gapless physical excitations. On this basis we construct a quotient algebra A≡BMS"H/BMS"− using suited superpositions of both kinds of transformations which cannot be compensated by an ordinary BMS-supertranslation and therefore are intrinsically due to the presence of an event horizon. We show that transformations in A are physical and generate gapless excitations on the horizon that can account for the gravitational hair as well as for the black hole entropy. We identify the physics of these modes as associated with Bogolioubov-Goldstone modes due to quantum criticality. Classically the number of these gapless modes is infinite. However, we show that due to quantum criticality the actual amount of information-carriers becomes finite and consistent with Bekenstein entropy. Although we only consider the case of Schwarzschild geometry, the arguments are extendable to arbitrary space-times containing event horizons.
Systematic survey for monitor signals to reduce fake burst events in a gravitational-wave detector
International Nuclear Information System (INIS)
Ishidoshiro, Koji; Ando, Masaki; Tsubono, Kimio
2006-01-01
We present methods and results to reduce fake burst events induced by nonstationary noises. To reduce these fake events, we systematically surveyed monitor signals recorded with a main (or gravitational-wave) signal of a gravitational-wave detector so as to watch the detector. Our survey was to check whether or not there was a coincidence between the main and monitor signals when we found a burst event from the main signal. If there was a coincidence, we rejected this event as a fake event induced by nonstationary noises, regarding the main signal as being dominated by nonstationary noises. As a result, we succeeded to reject about 90% of the burst events of which the SNR values were larger than 10 as fake events, with an accidental probability of about 5% to reject burst-gravitational-wave candidates
Misner, Charles W; Wheeler, John Archibald
2017-01-01
First published in 1973, Gravitation is a landmark graduate-level textbook that presents Einstein’s general theory of relativity and offers a rigorous, full-year course on the physics of gravitation. Upon publication, Science called it “a pedagogic masterpiece,” and it has since become a classic, considered essential reading for every serious student and researcher in the field of relativity. This authoritative text has shaped the research of generations of physicists and astronomers, and the book continues to influence the way experts think about the subject. With an emphasis on geometric interpretation, this masterful and comprehensive book introduces the theory of relativity; describes physical applications, from stars to black holes and gravitational waves; and portrays the field’s frontiers. The book also offers a unique, alternating, two-track pathway through the subject. Material focusing on basic physical ideas is designated as Track 1 and formulates an appropriate one-semester graduate-level...
Modified gravity (MOG), the speed of gravitational radiation and the event GW170817/GRB170817A
Green, M. A.; Moffat, J. W.; Toth, V. T.
2018-05-01
Modified gravity (MOG) is a covariant, relativistic, alternative gravitational theory whose field equations are derived from an action that supplements the spacetime metric tensor with vector and scalar fields. Both gravitational (spin 2) and electromagnetic waves travel on null geodesics of the theory's one metric. MOG satisfies the weak equivalence principle and is consistent with observations of the neutron star merger and gamma ray burster event GW170817/GRB170817A.
Swift pointing and gravitational-wave bursts from gamma-ray burst events
International Nuclear Information System (INIS)
Sutton, Patrick J; Finn, Lee Samuel; Krishnan, Badri
2003-01-01
The currently accepted model for gamma-ray burst phenomena involves the violent formation of a rapidly rotating solar-mass black hole. Gravitational waves should be associated with the black-hole formation, and their detection would permit this model to be tested. Even upper limits on the gravitational-wave strength associated with gamma-ray bursts could constrain the gamma-ray burst model. This requires joint observations of gamma-ray burst events with gravitational and gamma-ray detectors. Here we examine how the quality of an upper limit on the gravitational-wave strength associated with gamma-ray bursts depends on the relative orientation of the gamma-ray-burst and gravitational-wave detectors, and apply our results to the particular case of the Swift Burst-Alert Telescope (BAT) and the LIGO gravitational-wave detectors. A result of this investigation is a science-based 'figure of merit' that can be used, together with other mission constraints, to optimize the pointing of the Swift telescope for the detection of gravitational waves associated with gamma-ray bursts
Candidate gravitational microlensing events for future direct lens imaging
Energy Technology Data Exchange (ETDEWEB)
Henderson, C. B.; Gould, A.; Gaudi, B. S. [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Park, H.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Sumi, T.; Koshimoto, N. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Tsapras, Y. [Las Cumbres Observatory Global Telescope Network, 6740 Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Bozza, V. [Department of Physics, University of Salerno, I-84084 Fisciano (Italy); Abe, F.; Fukunaga, D.; Itow, Y.; Masuda, K. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Bond, I. A.; Ling, C. H. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland 0745 (New Zealand); Botzler, C. S.; Freeman, M. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Fukui, A. [School of Chemical and Physical Sciences, Victoria University, Wellington 6140 (New Zealand); Collaboration: MOA Collaboration; OGLE Collaboration; μFUN Collaboration; RoboNet Collaboration; and others
2014-10-10
The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be separated from that of the source, companions to the source, and unrelated nearby stars with high-resolution images taken when the lens and source are spatially resolved. For typical ground-based adaptive optics (AO) or space-based observations, this requires either inordinately long time baselines or high relative proper motions. We provide a list of microlensing events toward the Galactic bulge with high relative lens-source proper motion that are therefore good candidates for constraining the lens mass with future high-resolution imaging. We investigate all events from 2004 to 2013 that display detectable finite-source effects, a feature that allows us to measure the proper motion. In total, we present 20 events with μ ≳ 8 mas yr{sup –1}. Of these, 14 were culled from previous analyses while 6 are new, including OGLE-2004-BLG-368, MOA-2005-BLG-36, OGLE-2012-BLG-0211, OGLE-2012-BLG-0456, MOA-2012-BLG-532, and MOA-2013-BLG-029. In ≲12 yr from the time of each event the lens and source of each event will be sufficiently separated for ground-based telescopes with AO systems or space telescopes to resolve each component and further characterize the lens system. Furthermore, for the most recent events, comparison of the lens flux estimates from images taken immediately to those estimated from images taken when the lens and source are resolved can be used to empirically check the robustness of the single-epoch method currently being used to estimate lens masses for many events.
Candidate gravitational microlensing events for future direct lens imaging
International Nuclear Information System (INIS)
Henderson, C. B.; Gould, A.; Gaudi, B. S.; Park, H.; Han, C.; Sumi, T.; Koshimoto, N.; Udalski, A.; Tsapras, Y.; Bozza, V.; Abe, F.; Fukunaga, D.; Itow, Y.; Masuda, K.; Bennett, D. P.; Bond, I. A.; Ling, C. H.; Botzler, C. S.; Freeman, M.; Fukui, A.
2014-01-01
The mass of the lenses giving rise to Galactic microlensing events can be constrained by measuring the relative lens-source proper motion and lens flux. The flux of the lens can be separated from that of the source, companions to the source, and unrelated nearby stars with high-resolution images taken when the lens and source are spatially resolved. For typical ground-based adaptive optics (AO) or space-based observations, this requires either inordinately long time baselines or high relative proper motions. We provide a list of microlensing events toward the Galactic bulge with high relative lens-source proper motion that are therefore good candidates for constraining the lens mass with future high-resolution imaging. We investigate all events from 2004 to 2013 that display detectable finite-source effects, a feature that allows us to measure the proper motion. In total, we present 20 events with μ ≳ 8 mas yr –1 . Of these, 14 were culled from previous analyses while 6 are new, including OGLE-2004-BLG-368, MOA-2005-BLG-36, OGLE-2012-BLG-0211, OGLE-2012-BLG-0456, MOA-2012-BLG-532, and MOA-2013-BLG-029. In ≲12 yr from the time of each event the lens and source of each event will be sufficiently separated for ground-based telescopes with AO systems or space telescopes to resolve each component and further characterize the lens system. Furthermore, for the most recent events, comparison of the lens flux estimates from images taken immediately to those estimated from images taken when the lens and source are resolved can be used to empirically check the robustness of the single-epoch method currently being used to estimate lens masses for many events.
International Nuclear Information System (INIS)
Fennelly, A.J.
1978-01-01
Investigations of several problems of gravitation are discussed. The question of the existence of black holes is considered. While black holes like those in Einstein's theory may not exist in other gravity theories, trapped surfaces implying such black holes certainly do. The theories include those of Brans-Dicke, Lightman-Lee, Rosen, and Yang. A similar two-tensor theory of Yilmaz is investigated and found inconsistent and nonviable. The Newman-Penrose formalism for Riemannian geometries is adapted to general gravity theories and used to implement a search for twisting solutions of the gravity theories for empty and nonempty spaces. The method can be used to find the gravitational fields for all viable gravity theories. The rotating solutions are of particular importance for strong field interpretation of the Stanford/Marshall gyroscope experiment. Inhomogeneous cosmologies are examined in Einstein's theory as generalizations of homogeneous ones by raising the dimension of the invariance groups by one more parameter. The nine Bianchi classifications are extended to Rosen's theory of gravity for homogeneous cosmological models
Gando, A.; Gando, Y.; Hachiya, T.; Hayashi, A.; Hayashida, S.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Karino, Y.; Koga, M.; Matsuda, S.; Mitsui, T.; Nakamura, K.; Obara, S.; Oura, T.; Ozaki, H.; Shimizu, I.; Shirahata, Y.; Shirai, J.; Suzuki, A.; Takai, T.; Tamae, K.; Teraoka, Y.; Ueshima, K.; Watanabe, H.; Kozlov, A.; Takemoto, Y.; Yoshida, S.; Fushimi, K.; Piepke, A.; Banks, T.I.; Berger, B.E.; Fujikawa, B.K.; O'Donnell, T.; Learned, J.G.; Maricic, J.; Sakai, M.; Winslow, L.A.; Krupczak, E.; Ouellet, J.; Efremenko, Y.; Karwowski, H.J.; Markoff, D.M.; Tornow, W.; Detwiler, J.A.; Enomoto, S.; Decowski, M.P.
2016-01-01
We present a search, using KamLAND, a kiloton-scale anti-neutrino detector, for low-energy anti-neutrino events that were coincident with the gravitational-wave (GW) events GW150914 and GW151226, and the candidate event LVT151012. We find no inverse beta-decay neutrino events within ±500 s of either
Energy Technology Data Exchange (ETDEWEB)
Karami, K; Ghaffari, S; Soltanzadeh, M M, E-mail: KKarami@uok.ac.i [Department of Physics, University of Kurdistan, Pasdaran St, Sanandaj (Iran, Islamic Republic of)
2010-10-21
We investigate the validity of the generalized second law (GSL) of gravitational thermodynamics on the apparent and event horizons in a non-flat Friedmann-Robertson-Walker (FRW) universe containing dark energy interacting with dark matter. We show that for the dynamical apparent horizon, the GSL is always satisfied throughout the history of the universe for any spatial curvature and it is independent of the equation of state parameter of the interacting dark energy model. On the other hand, for the cosmological event horizon, the validity of the GSL depends on the equation of state parameter of the model.
International Nuclear Information System (INIS)
Karami, K; Ghaffari, S; Soltanzadeh, M M
2010-01-01
We investigate the validity of the generalized second law (GSL) of gravitational thermodynamics on the apparent and event horizons in a non-flat Friedmann-Robertson-Walker (FRW) universe containing dark energy interacting with dark matter. We show that for the dynamical apparent horizon, the GSL is always satisfied throughout the history of the universe for any spatial curvature and it is independent of the equation of state parameter of the interacting dark energy model. On the other hand, for the cosmological event horizon, the validity of the GSL depends on the equation of state parameter of the model.
Indico central - events organisation, ergonomics and collaboration tools integration
International Nuclear Information System (INIS)
Gonzalez Lopez, Jose Benito; Ferreira, Jose Pedro; Baron, Thomas
2010-01-01
While the remote collaboration services at CERN slowly aggregate around the Indico event management software, its new version which is the result of a careful maturation process includes improvements which will set a new reference in its domain. The presentation will focus on the description of the new features of the tool, the user feedback process which resulted in a new record of usability. We will also describe the interactions with the worldwide community of users and server administrators and the impact this has had on our development process, as well as the tools set in place to streamline the work between the different collaborating sites. A last part will be dedicated to the use of Indico as a central hub for operating other local services around the event organisation (registration epayment, audiovisual recording, webcast, room booking, and videoconference support)
Indico central - events organisation, ergonomics and collaboration tools integration
Energy Technology Data Exchange (ETDEWEB)
Gonzalez Lopez, Jose Benito; Ferreira, Jose Pedro; Baron, Thomas, E-mail: jose.benito.gonzalez@cern.c, E-mail: jose.pedro.ferreira@cern.c, E-mail: thomas.baron@cern.c [CERN IT-UDS-AVC, 1211 Geneve 23 (Switzerland)
2010-04-01
While the remote collaboration services at CERN slowly aggregate around the Indico event management software, its new version which is the result of a careful maturation process includes improvements which will set a new reference in its domain. The presentation will focus on the description of the new features of the tool, the user feedback process which resulted in a new record of usability. We will also describe the interactions with the worldwide community of users and server administrators and the impact this has had on our development process, as well as the tools set in place to streamline the work between the different collaborating sites. A last part will be dedicated to the use of Indico as a central hub for operating other local services around the event organisation (registration epayment, audiovisual recording, webcast, room booking, and videoconference support)
Indico Central - Events Organisation, Ergonomics and Collaboration Tools Integration
Gonzalez Lopez, J B; Baron, T; CERN. Geneva. IT Department
2010-01-01
While the remote collaboration services at CERN slowly aggregate around the Indico event management software, its new version which is the result of a careful maturation process includes improvements which will set a new reference in its domain. The presentation will focus on the description of the new features of the tool, the user feedback process which resulted in a new record of usability. We will also describe the interactions with the worldwide community of users and server administrators and the impact this has had on our development process, as well as the tools set in place to streamline the work between the different collaborating sites. A last part will be dedicated to the use of Indico as a central hub for operating other local services around the event organisation (registration epayment, audiovisual recording, webcast, room booking, and videoconference support)
International Nuclear Information System (INIS)
Abe, K.; Haga, K.; Hayato, Y.; Ikeda, M.; Iyogi, K.; Kameda, J.; Kishimoto, Y.; Miura, M.; Moriyama, S.; Nakahata, M.; Nakajima, T.; Nakano, Y.; Nakayama, S.; Orii, A.; Sekiya, H.; Shiozawa, M.; Takeda, A.; Tanaka, H.; Tasaka, S.; Tomura, T.
2016-01-01
We report the results from a search in Super-Kamiokande for neutrino signals coincident with the first detected gravitational-wave events, GW150914 and GW151226, as well as LVT151012, using a neutrino energy range from 3.5 MeV to 100 PeV. We searched for coincident neutrino events within a time window of ±500 s around the gravitational-wave detection time. Four neutrino candidates are found for GW150914, and no candidates are found for GW151226. The remaining neutrino candidates are consistent with the expected background events. We calculated the 90% confidence level upper limits on the combined neutrino fluence for both gravitational-wave events, which depends on event energy and topologies. Considering the upward-going muon data set (1.6 GeV–100 PeV), the neutrino fluence limit for each gravitational-wave event is 14–37 (19–50) cm"−"2 for muon neutrinos (muon antineutrinos), depending on the zenith angle of the event. In the other data sets, the combined fluence limits for both gravitational-wave events range from 2.4 × 10"4 to 7.0 × 10"9 cm"−"2.
Some little-known facts and events from the history of gravitational wave research in Ukraine
Yatskiv, Ya. S.,; Vavilova, I. B.; Romanets, O. A.; Savchuk, V. S.
2017-10-01
The paper deals with the history of gravitational wave research in Ukraine and describes two little-known facts and events. The first one is concerning with a short period of Dr. Nathan Rosen's life in Kyiv and his scientific activity at the Institute of Physics of the Academy of Sciences of the UkrSSR in 1936-1938 years. At that time, he has published several papers, which promoted the first steps in the creation of modern theories in the fields of gravity and quantum physics. These papers, including "Plane-polarized waves in the General Theory of Relativity", have been issued in the "Ukrainian Physical Notes" ("Ukrainski Fizychni Zapysky"), which was not widely accessed. We quote also some parts from correspondence of N. Rosen and A. Einstein in this period. The second comment is related to the history of gravitational wave experimental research in Kyiv, which were initiated in 1970s by Prof. Aleksey Z. Petrov at the Institute of Theoretical Physics of the Academy of Sciences of the UkrSSR. We describe briefly the development of the detector of high-frequency gravitational waves (the Weber type antenna) as well as results obtained by K.A. Piragas's group.
Fermi GBM Observations of LIGO Gravitational-Wave Event Gw150914
Connaughton, V.; Burns, E.; Goldstein, A.; Blackburn, L.; Briggs, M. S.; Zhang, B.-B.; Camp, J.; Christensen, N.; Hui, C. M.; Jenke, P.;
2016-01-01
With an instantaneous view of 70% of the sky, the Fermi Gamma-ray Burst Monitor (GBM) is an excellent partner in the search for electromagnetic counterparts to gravitational-wave (GW) events. GBM observations at the time of the Laser Interferometer Gravitational-wave Observatory (LIGO) event GW150914 reveal the presence of a weak transient above 50 keV, 0.4 s after the GW event, with a false-alarm probability of 0.0022 (2.9(sigma)). This weak transient lasting 1 s was not detected by any other instrument and does not appear to be connected with other previously known astrophysical, solar, terrestrial, or magnetospheric activity. Its localization is ill-constrained but consistent with the direction of GW150914. The duration and spectrum of the transient event are consistent with a weak short gamma-ray burst (GRB) arriving at a large angle to the direction in which Fermi was pointing where the GBM detector response is not optimal. If the GBM transient is associated with GW150914, then this electromagnetic signal from a stellar mass black hole binary merger is unexpected. We calculate a luminosity in hard X-ray emission between 1 keV and 10 MeV of 1.8(sup +1.5, sub -1.0) x 10(exp 49) erg/s. Future joint observations of GW events by LIGO/Virgo and Fermi GBM could reveal whether the weak transient reported here is a plausible counterpart to GW150914 or a chance coincidence, and will further probe the connection between compact binary mergers and short GRBs.
Statistical improvement in detection level of gravitational microlensing events from their light curves
Ibrahim, Ichsan; Malasan, Hakim L.; Kunjaya, Chatief; Timur Jaelani, Anton; Puannandra Putri, Gerhana; Djamal, Mitra
2018-04-01
In astronomy, the brightness of a source is typically expressed in terms of magnitude. Conventionally, the magnitude is defined by the logarithm of received flux. This relationship is known as the Pogson formula. For received flux with a small signal to noise ratio (S/N), however, the formula gives a large magnitude error. We investigate whether the use of Inverse Hyperbolic Sine function (hereafter referred to as the Asinh magnitude) in the modified formulae could allow for an alternative calculation of magnitudes for small S/N flux, and whether the new approach is better for representing the brightness of that region. We study the possibility of increasing the detection level of gravitational microlensing using 40 selected microlensing light curves from the 2013 and 2014 seasons and by using the Asinh magnitude. Photometric data of the selected events are obtained from the Optical Gravitational Lensing Experiment (OGLE). We found that utilization of the Asinh magnitude makes the events brighter compared to using the logarithmic magnitude, with an average of about 3.42 × 10‑2 magnitude and an average in the difference of error between the logarithmic and the Asinh magnitude of about 2.21 × 10‑2 magnitude. The microlensing events OB140847 and OB140885 are found to have the largest difference values among the selected events. Using a Gaussian fit to find the peak for OB140847 and OB140885, we conclude statistically that the Asinh magnitude gives better mean squared values of the regression and narrower residual histograms than the Pogson magnitude. Based on these results, we also attempt to propose a limit in magnitude value for which use of the Asinh magnitude is optimal with small S/N data.
The Distance to NGC 4993: The Host Galaxy of the Gravitational-wave Event GW170817
Hjorth, Jens; Levan, Andrew J.; Tanvir, Nial R.; Lyman, Joe D.; Wojtak, Radosław; Schrøder, Sophie L.; Mandel, Ilya; Gall, Christa; Bruun, Sofie H.
2017-10-01
The historic detection of gravitational waves from a binary neutron star merger (GW170817) and its electromagnetic counterpart led to the first accurate (sub-arcsecond) localization of a gravitational-wave event. The transient was found to be ˜10″ from the nucleus of the S0 galaxy NGC 4993. We report here the luminosity distance to this galaxy using two independent methods. (1) Based on our MUSE/VLT measurement of the heliocentric redshift (z helio = 0.009783 ± 0.000023), we infer the systemic recession velocity of the NGC 4993 group of galaxies in the cosmic microwave background (CMB) frame to be v CMB = 3231 ± 53 km s-1. Using constrained cosmological simulations we estimate the line-of-sight peculiar velocity to be v pec = 307 ± 230 km s-1, resulting in a cosmic velocity of v cosmic = 2924 ± 236 km s-1 (z cosmic = 0.00980 ± 0.00079) and a distance of D z = 40.4 ± 3.4 Mpc assuming a local Hubble constant of H 0 = 73.24 ± 1.74 km s-1 Mpc-1. (2) Using Hubble Space Telescope measurements of the effective radius (15.″5 ± 1.″5) and contained intensity and MUSE/VLT measurements of the velocity dispersion, we place NGC 4993 on the Fundamental Plane (FP) of E and S0 galaxies. Comparing to a frame of 10 clusters containing 226 galaxies, this yields a distance estimate of D FP = 44.0 ± 7.5 Mpc. The combined redshift and FP distance is D NGC 4993 = 41.0 ± 3.1 Mpc. This “electromagnetic” distance estimate is consistent with the independent measurement of the distance to GW170817 as obtained from the gravitational-wave signal ({D}{GW}={43.8}-6.9+2.9 Mpc) and confirms that GW170817 occurred in NGC 4993.
CERN. Geneva
2016-01-01
In the past year, the LIGO-Virgo Collaboration announced the first secure detection of gravitational waves. This discovery heralds the beginning of gravitational wave astronomy: the use of gravitational waves as a tool for studying the dense and dynamical universe. In this talk, I will describe the full spectrum of gravitational waves, from Hubble-scale modes, through waves with periods of years, hours and milliseconds. I will describe the different techniques one uses to measure the waves in these bands, current and planned facilities for implementing these techniques, and the broad range of sources which produce the radiation. I will discuss what we might expect to learn as more events and sources are measured, and as this field matures into a standard part of the astronomical milieu.
Albert, A.; Andre, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J. -J.; Avgitas, T.; Baret, B.; Barrios-Marti, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M. C.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coelho, J. A. B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; Di Palma, I.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsaesser, D.; Enzenhofer, A.; Felis, I.; Fusco, L. A.; Galata, S.; Gay, P.; Giordano, V.; Glotin, H.; Gregoire, T.; Ruiz, R. Gracia; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernandez-Rey, J. J.; Hoessl, J.; Hofestaedt, J.; Hugon, C.; Illuminati, G.; James, C. W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kiessling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefevre, D.; Leonora, E.; Lotze, M.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martinez-Mora, J. A.; Mathieu, A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Nezri, E.; Pavalas, G. E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Sanchez-Losa, A.; Saldana, M.; Salvadori, I.; Samtleben, D. F. E.; Sanguineti, M.; Sapienza, P.; Schussler, F.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Turpin, D.; Tonnis, C.; Vallage, B.; Vallee, C.; Van Elewyck, V.; Versari, F.; Vivolo, D.; Vizzoca, A.; Wilms, J.; Zornoza, J. D.; Zuniga, J.; Aartsen, M. G.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Ahrens, M.; Al Samarai, I.; Altmann, D.; Andeen, K.; Anderson, T.; Ansseau, I.; Anton, G.; Archinger, M.; Arguelles, C.; Auffenberg, J.; Axani, S.; Bagherpour, H.; Bai, X.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Tjus, J. Becker; Becker, K. -H.; BenZvi, S.; Berley, D.; Bernardini, E.; Besson, D. Z.; Binder, G.; Bindig, D.; Blaufuss, E.; Blot, S.; Bohm, C.; Borner, M.; Bos, F.; Bose, D.; Boser, S.; Botner, O.; Bradascio, F.; Braun, J.; Brayeur, L.; Bretz, H. -P.; Bron, S.; Burgman, A.; Carver, T.; Casier, M.; Cheung, E.; Chirkin, D.; Christov, A.; Clark, K.; Classen, L.; Coenders, S.; Collin, G. H.; Conrad, J. M.; Cowen, D. F.; Cross, R.; Day, M.; de Andre, J. P. A. M.; De Clercq, C.; Rosendo, E. del Pino; Dembinski, H.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de Wasseige, G.; de With, M.; DeYoung, T.; Diaz-Velez, J. C.; di Lorenzo, V.; Dujmovic, H.; Dumm, J. P.; Dunkman, M.; Eberhardt, B.; Ehrhardt, T.; Eichmann, B.; Eller, P.; Euler, S.; Evenson, P. A.; Fahey, S.; Fazely, A. R.; Feintzeig, J.; Felde, J.; Filimonov, K.; Finley, C.; Flis, S.; Fosig, C. -C.; Franckowiak, A.; Friedman, E.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Ghorbani, K.; Giang, W.; Gladstone, L.; Glauch, T.; Gluesenkamp, T.; Goldschmidt, A.; Gonzalez, J. G.; Grant, D.; Griffith, Z.; Haack, C.; Hallgren, A.; Halzen, F.; Hansen, E.; Hansmann, T.; Hanson, K.; Hebecker, D.; Heereman, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hignight, J.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Hoshina, K.; Huang, F.; Huber, M.; Hultqvist, K.; In, S.; Ishihara, A.; Jacobi, E.; Japaridze, G. S.; Jeong, M.; Jero, K.; Jones, B. J. P.; Kang, W.; Kappes, A.; Karg, T.; Karle, A.; Katz, U.; Kauer, M.; Keivani, A.; Kelley, J. L.; Kheirandish, A.; Kim, J.; Kim, M.; Kintscher, T.; Kiryluk, J.; Kittler, T.; Klein, S. R.; Kohnen, G.; Koirala, R.; Kolanoski, H.; Konietz, R.; Kopke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krings, K.; Kroll, M.; Kruckl, G.; Kruger, C.; Kunnen, J.; Kunwar, S.; Kurahashi, N.; Kuwabara, T.; Kyriacou, A.; Labare, M.; Lanfranchi, J. L.; Larson, M. J.; Lauber, F.; Lennarz, D.; Lesiak-Bzdak, M.; Leuermann, M.; Lu, L.; Lunemann, J.; Madsen, J.; Maggi, G.; Mahn, K. B. M.; Mancina, S.; Maruyama, R.; Mase, K.; Maunu, R.; McNally, F.; Meagher, K.; Medici, M.; Meier, M.; Menne, T.; Merino, G.; Meures, T.; Miarecki, S.; Micallef, J.; Momente, G.; Montaruli, T.; Moulai, M.; Nahnhauer, R.; Naumann, U.; Neer, G.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Pollmann, A. Obertacke; Olivas, A.; O'Murchadha, A.; Palczewski, T.; Pandya, H.; Pankova, D. V.; Peiffer, P.; Penek, O.; Pepper, J. A.; de los Heros, C. Perez; Pieloth, D.; Pinat, E.; Price, P. B.; Przybylski, G. T.; Quinnan, M.; Raab, C.; Raedel, L.; Rameez, M.; Rawlins, K.; Reimann, R.; Relethford, B.; Relich, M.; Resconi, E.; Rhode, W.; Richman, M.; Riedel, B.; Robertson, S.; Rongen, M.; Rott, C.; Ruhe, T.; Ryckbosch, D.; Rysewyk, D.; Sabbatini, L.; Herrera, S. E. Sanchez; Sandrock, A.; Sandroos, J.; Sarkar, S.; Satalecka, K.; Schlunder, P.; Schmidt, T.; Schoenen, S.; Schoeneberg, S.; Schumacher, L.; Seckel, D.; Seunarine, S.; Soldin, D.; Song, M.; Spiczak, G. M.; Spiering, C.; Stachurska, J.; Stanev, T.; Stasik, A.; Stettner, J.; Steuer, A.; Stezelberger, T.; Stokstad, R. G.; Stossl, A.; Strom, R.; Strotjohann, N. L.; Sullivan, G. W.; Sutherland, M.; Taavola, H.; Taboada, I.; Tatar, J.; Tenholt, F.; Ter-Antonyan, S.; Terliuk, A.; Tesic, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Toscano, S.; Tosi, D.; Tselengidou, M.; Tung, C. F.; Turcati, A.; Unger, E.; Usner, M.; Vandenbroucke, J.; van Eijndhoven, N.; Vanheule, S.; van Rossem, M.; van Santen, J.; Vehring, M.; Voge, M.; Vogel, E.; Vraeghe, M.; Walck, C.; Wallace, A.; Wallraff, M.; Wandkowsky, N.; Waza, A.; Weaver, Ch.; Weiss, M. J.; Wendt, C.; Westerhoff, S.; Whelan, B. J.; Wickmann, S.; Wiebe, K.; Wiebusch, C. H.; Wille, L.; Williams, D. R.; Wills, L.; Wolf, M.; Wood, T. R.; Woolsey, E.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Xu, Y.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zoll, M.; Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allocca, A.; Altin, P. A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Aufmuth, P.; Aulbert, C.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; D. Barta,; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Beer, C.; Bejger, M.; Belahcene, I.; Belgin, M.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackman, J.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Boer, M.; Bogaert, G.; Bohe, A.; Bondu, F.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Braginsky, V. B.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brown, N. M.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cabero, M.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Bustillo, J. Calderon; Callister, T. A.; Calloni, E.; Camp, J. B.; Canepa, M.; Cannon, K. C.; Cao, H.; Cao, J.; Capano, C. D.; Capocasa, E.; Carbognani, F.; Caride, S.; Diaz, J. Casanueva; Casentini, C.; Caudill, S.; Cavaglia, M.; Cavalier, F.; Cavalieri, R.; Cella, G.; Cepeda, C. B.; Baiardi, L. Cerboni; Cerretani, G.; Cesarini, E.; Chamberlin, S. J.; Chan, M.; Chao, S.; Charlton, P.; Chassande-Mottin, E.; Cheeseboro, B. D.; Chen, H. Y.; Chen, Y.; Cheng, H. -P.; Chincarini, A.; Chiummo, A.; Chmiel, T.; Cho, H. S.; Cho, M.; Chow, J. H.; Christensen, N.; Chu, Q.; Chua, A. J. K.; Chua, S.; Chung, S.; Ciani, G.; Clara, F.; Clark, J. A.; Cleva, F.; Cocchieri, C.; Coccia, E.; Cohadon, P. -F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M., Jr.; Conti, L.; Cooper, S. J.; 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.; Covas, P. B.; Cowan, E. E.; Coward, D. M.; Cowart, M. J.; Coyne, D. C.; Coyne, R.; Creighton, J. D. E.; Creighton, T. D.; Cripe, J.; Crowder, S. G.; Cullen, T. J.; Cumming, A.; Cunningham, L.; Cuoco, E.; Dal Canton, T.; Danilishin, S. L.; D'Antonio, S.; Danzmann, K.; Dasgupta, A.; Costa, C. F. Da Silva; Dattilo, V.; Dave, I.; Davier, M.; Davies, G. S.; Davis, D.; Daw, E. J.; Day, B.; Day, R.; De, S.; DeBra, D.; G. Debreczeni,; Degallaix, J.; De Laurentis, M.; Deleglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dergachev, V.; De Rosa, R.; DeRosa, R. T.; DeSalvo, R.; Devine, R. C.; Dhurandhar, S.; Diaz, M. C.; Di Fiore, L.; Di Giovanni, M.; Di Girolamo, T.; Di Lieto, A.; Di Pace, S.; Di Palma, I.; Di Virgilio, A.; Doctor, Z.; Dolique, V.; Donovan, F.; Dooley, K. L.; Doravari, S.; Dorrington, I.; Douglas, R.; Alvarez, M. Dovale; 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.; Eisenstein, R. A.; Essick, R. C.; Etienne, Z.; Etzel, T.; Evans, M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E. J.; Favata, M.; Fays, M.; Fehrmann, H.; Fejer, M. M.; Galiana, A. Fernandez; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Fiori, I.; Fiorucci, D.; Fisher, R. P.; Flaminio, R.; Fletcher, M.; Fong, H.; Forsyth, S. S.; Fournier, J. -D.; Frasca, S.; Frasconi, F.; Z. Frei,; Freise, A.; Frey, R.; Frey, V.; Fries, E. M.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H.; Gadre, B. U.; Gaebel, S. M.; Gair, J. R.; Gammaitoni, L.; Gaonkar, S. G.; Garufi, F.; Gaur, G.; Gayathri, V.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, J.; L. Gergely,; Germain, V.; Ghonge, S.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glaefke, A.; Goetz, E.; Goetz, R.; L. Gondan,; Gonzalez, G.; Castro, J. M. Gonzalez; Gopakumar, A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Hall, B. R.; Hall, E. D.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C. -J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Henry, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J. -M.; Isi, M.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jimenez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Junker, J.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kefelian, F.; Keitel, D.; Kelley, D. B.; Kennedy, R.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J. C.; Kim, Whansun; Kim, W.; Kim, Y. -M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kirchhoff, R.; Kissel, J. S.; Klein, B.; Kleybolte, L.; Klimenko, S.; Koch, P.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kraemer, C.; Kringel, V.; Krolak, A.; Kuehn, G.; Kumar, P.; Kumar, R.; Kuo, L.; Kutynia, A.; Lackey, B. D.; Landry, M.; Lang, R. N.; Lange, J.; Lantz, B.; Lanza, R. K.; Lartaux-Vollard, A.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lebigot, E. O.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, K.; Lehmann, J.; Lenon, A.; Leonardi, M.; Leong, J. R.; Leroy, N.; Letendre, N.; Levin, Y.; Li, T. G. F.; Libson, A.; Littenberg, T. B.; Liu, J.; Lockerbie, N. A.; Lombardi, A. L.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lovelace, G.; Lueck, H.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macfoy, S.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-Sandoval, F.; Majorana, E.; Maksimovic, I.; Malvezzi, V.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Marka, S.; Marka, Z.; Markosyan, A. S.; Maros, E.; Martelli, F.; Martellini, L.; Martin, I. W.; Martynov, D. V.; Mason, K.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McGrath, C.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; Mcrae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Meidam, J.; Melatos, A.; Mendell, G.; Mendoza-Gandara, D.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Mezzani, F.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, A.; Miller, B. B.; Miller, J.; Millhouse, M.; Minenkov, Y.; Ming, J.; Mirshekari, S.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moggi, A.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, B. C.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Muniz, E. A. M.; Murray, P. G.; Mytidis, A.; Napier, K.; Nardecchia, I.; Naticchioni, L.; Nelemans, G.; Nelson, T. J. N.; Neri, M.; Nery, M.; Neunzert, A.; Newport, J. M.; Newton, G.; Nguyen, T. T.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Noack, A.; Nocera, F.; Nolting, D.; Normandin, M. E. N.; Nuttall, L. K.; Oberling, J.; Ochsner, E.; Oelker, E.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; O'Shaughnessy, R.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pace, A. E.; Page, J.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patricelli, B.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perez, C. J.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Post, A.; Powell, J.; Prasad, J.; Pratt, J. W. W.; Predoi, V.; Prestegard, T.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Puerrer, M.; Qi, H.; Qin, J.; Qiu, S.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; P. Raffai,; Raja, S.; Rajan, C.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Rhoades, E.; Ricci, F.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, R.; Romie, J. H.; Rosinska, D.; Rowan, S.; Ruediger, A.; Ruggi, P.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sampson, L. M.; Sanchez, E. J.; Sandberg, V.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Scheuer, J.; Schmidt, E.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schoenbeck, A.; Schreiber, E.; Schuette, D.; Schutz, B. F.; Schwalbe, S. G.; Scott, J.; Scott, S. M.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Setyawati, Y.; Shaddock, D. A.; Shaffer, T. J.; Shahriar, M. S.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, A.; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, B.; Smith, R. J. E.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Spencer, A. P.; Srivastava, A. K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stevenson, S. P.; Stone, R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strigin, S. E.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Sutton, P. J.; Swinkels, B. L.; Szczepanczyk, M. J.; Tacca, M.; Talukder, D.; Tanner, D. B.; M. Tapai,; Taracchini, A.; Taylor, R.; Theeg, T.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tippens, T.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tomlinson, C.; Tonelli, M.; Tornasi, Z.; Torrie, C. I.; Toyra, D.; Travasso, F.; Traylor, G.; Trifiro, D.; Trinastic, J.; Tringali, M. C.; Trozzo, L.; Tse, M.; Tso, R.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Varma, V.; Vass, S.; M. Vasuth,; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Venugopalan, G.; Verkindt, D.; Vetrano, F.; Vicere, A.; Viets, A. D.; Vinciguerra, S.; Vine, D. J.; Vinet, J. -Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, M.; Wang, Y.; Ward, R. L.; Warner, J.; Was, M.; Watchi, J.; Weaver, B.; Wei, L. -W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Whittle, C.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Worden, J.; Wright, J. L.; Wu, D. S.; Wu, G.; Yam, W.; Yamamoto, H.; Yancey, C. C.; Yap, M. J.; Yu, Hang; Yu, Haocun; Yvert, M.; Zadrozny, A.; Zangrando, L.; Zanolin, M.; Zendri, J. -P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, T.; Zhang, Y.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, S. J.; Zhu, X. J.; Zucker, M. E.; Zweizig, J.
2017-01-01
The Advanced LIGO observatories detected gravitational waves from two binary black hole mergers during their first observation run (O1). We present a high-energy neutrino follow-up search for the second gravitational wave event, GW151226, as well as for gravitational wave candidate LVT151012. We
Detections of Planets in Binaries Through the Channel of Chang–Refsdal Gravitational Lensing Events
Energy Technology Data Exchange (ETDEWEB)
Han, Cheongho [Department of Physics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Shin, In-Gu; Jung, Youn Kil [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States)
2017-02-01
Chang–Refsdal (C–R) lensing, which refers to the gravitational lensing of a point mass perturbed by a constant external shear, provides a good approximation in describing lensing behaviors of either a very wide or a very close binary lens. C–R lensing events, which are identified by short-term anomalies near the peak of high-magnification lensing light curves, are routinely detected from lensing surveys, but not much attention is paid to them. In this paper, we point out that C–R lensing events provide an important channel to detect planets in binaries, both in close and wide binary systems. Detecting planets through the C–R lensing event channel is possible because the planet-induced perturbation occurs in the same region of the C–R lensing-induced anomaly and thus the existence of the planet can be identified by the additional deviation in the central perturbation. By presenting the analysis of the actually observed C–R lensing event OGLE-2015-BLG-1319, we demonstrate that dense and high-precision coverage of a C–R lensing-induced perturbation can provide a strong constraint on the existence of a planet in a wide range of planet parameters. The sample of an increased number of microlensing planets in binary systems will provide important observational constraints in giving shape to the details of planet formation, which have been restricted to the case of single stars to date.
A Model of Dust-like Spherically Symmetric Gravitational Collapse without Event Horizon Formation
Directory of Open Access Journals (Sweden)
Piñol M.
2015-10-01
Full Text Available Some dynamical aspects of gravitational collapse are explored in this paper. A time- dependent spherically symmetric metric is proposed and the corresponding Einstein field equations are derived. An ultrarelativistic dust-like stress-momentum tensor is considered to obtain analytical solutions of these equations, with the perfect fluid con- sisting of two purely radial fluxes — the inwards flux of collapsing matter and the outwards flux of thermally emitted radiation. Thermal emission is calculated by means of a simplistic but illustrative model of uninteracting collapsing shells. Our results show an asymptotic approach to a maximal space-time deformation without the formation of event horizons. The size of the body is slightly larger than the Schwarzschild radius during most of its lifetime, so that there is no contradiction with either observations or previous theorems on black holes. The relation of the latter with our results is scruti- nized in detail.
DEFF Research Database (Denmark)
Parker, M. L.; Wilkins, D. R.; Fabian, A. C.
2014-01-01
gravitational radii (R-G) of the event horizon. The reflection fraction decreases sharply with increasing flux, consistent with a point source moving up to above 10 R-G as the source brightens. We constrain the spin parameter to greater than 0.9 at the 3 sigma confidence level. By adding a spin-dependent upper...
The two event horizons - an apparent contribution of vacuum to gravitation
International Nuclear Information System (INIS)
Dinculescu, A.
1994-01-01
Our possibilities of investigation are limited by two horizons: a local one - the black hole horizon R 0 , and the global one - the cosmic horizon R u . Till now, only the first horizon has been taken into consideration as a measure of the curvature of space near a massive body. It is argued that in order to satisfy Mach's principle when characterizing matter in a point relative to a center of mass, one has to take into consideration both event horizons. Accordingly, a local cosmological term Λ * =(R 0 R u ) -1 is defined as a combination of the above horizons in a given point. The corresponding non-dimensional coefficient ξ=Λ * R 2 is an indicator of the position of a mass point between the two event horizons. When taking into account as a contribution of vacuum energy to the gravitational field it restores the low of conservation of energy in an expanding universe, and explains the dynamics of galaxies and clusters of galaxies without resorting to the 'dark matter' hypothesis. (Author) 3 Tabs., 38 Refs
XMM-NEWTON SLEW SURVEY OBSERVATIONS OF THE GRAVITATIONAL WAVE EVENT GW150914
Energy Technology Data Exchange (ETDEWEB)
Troja, E. [NASA Goddard Space Flight Center, 8800 Greenbelt Rd, Greenbelt, MD 20771 (United States); Read, A. M. [Department of Physics and Astronomy, Leicester University, Leicester LE1 7RH (United Kingdom); Tiengo, A. [Istituto Universitario di Studi Superiori, piazza della Vittoria 15, I-27100 Pavia (Italy); Salvaterra, R. [Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, INAF, via E. Bassini 15, I-20133 Milano (Italy)
2016-05-01
The detection of the first gravitational wave (GW) transient GW150914 prompted an extensive campaign of follow-up observations at all wavelengths. Although no dedicated XMM-Newton observations have been performed, the satellite passed through the GW150914 error region during normal operations. Here we report the analysis of the data taken during these satellite slews performed two hours and two weeks after the GW event. Our data cover 1.1 and 4.8 deg{sup 2} of the final GW localization region. No X-ray counterpart to GW150914 is found down to a sensitivity of 6 × 10{sup −13} erg cm{sup −2} s{sup −1} in the 0.2–2 keV band. Nevertheless, these observations show the great potential of XMM-Newton slew observations for searching for the electromagnetic counterparts of GW events. A series of adjacent slews performed in response to a GW trigger would take ≲1.5 days to cover most of the typical GW credible region. We discuss this scenario and its prospects for detecting the X-ray counterpart of future GW detections.
Gando, A.; Gando, Y.; Hachiya, T.; Hayashi, A.; Hayashida, S.; Ikeda, H.; Inoue, K.; Ishidoshiro, K.; Karino, Y.; Koga, M.; Matsuda, S.; Mitsui, T.; Nakamura, K.; Obara, S.; Oura, T.; Ozaki, H.; Shimizu, I.; Shirahata, Y.; Shirai, J.; Suzuki, A.; Takai, T.; Tamae, K.; Teraoka, Y.; Ueshima, K.; Watanabe, H.; Kozlov, A.; Takemoto, Y.; Yoshida, S.; Fushimi, K.; Piepke, A.; Banks, T. I.; Berger, B. E.; Fujikawa, B. K.; O'Donnell, T.; Learned, J. G.; Maricic, J.; Sakai, M.; Winslow, L. A.; Krupczak, E.; Ouellet, J.; Efremenko, Y.; Karwowski, H. J.; Markoff, D. M.; Tornow, W.; Detwiler, J. A.; Enomoto, S.; Decowski, M. P.; KamLAND Collaboration
2016-10-01
We present a search, using KamLAND, a kiloton-scale anti-neutrino detector, for low-energy anti-neutrino events that were coincident with the gravitational-wave (GW) events GW150914 and GW151226, and the candidate event LVT151012. We find no inverse beta-decay neutrino events within ±500 s of either GW signal. This non-detection is used to constrain the electron anti-neutrino fluence and the total integrated luminosity of the astrophysical sources.
Energy Technology Data Exchange (ETDEWEB)
Annis, J.; Soares-Santos, M.; Diehl, H. T.; Drlica-Wagner, A.; Finley, D. A.; Flaugher, B.; Frieman, J.; Herner, K. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Berger, E.; Cowperthwaite, P. S.; Drout, M. R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Brout, D. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Chen, H.; Doctor, Z.; Farr, B.; Holz, D.; Kessler, R. [Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Chornock, R. [Astrophysical Institute, Department of Physics and Astronomy, Ohio University, 251B Clippinger Lab, Athens, OH 45701 (United States); Foley, R. J.; Gruendl, R. A. [Department of Astronomy, University of Illinois, 1002 W. Green Street, Urbana, IL 61801 (United States); Collaboration: DES Collaboration; and others
2016-06-01
The collapse of a stellar core is expected to produce gravitational waves (GWs), neutrinos, and in most cases a luminous supernova. Sometimes, however, the optical event could be significantly less luminous than a supernova and a direct collapse to a black hole, where the star just disappears, is possible. The GW event GW150914 was detected by the LIGO Virgo Collaboration via a burst analysis that gave localization contours enclosing the Large Magellanic Cloud (LMC). Shortly thereafter, we used DECam to observe 102 deg{sup 2} of the localization area, including 38 deg{sup 2} on the LMC for a missing supergiant search. We construct a complete catalog of LMC luminous red supergiants, the best candidates to undergo invisible core collapse, and collected catalogs of other candidates: less luminous red supergiants, yellow supergiants, blue supergiants, luminous blue variable stars, and Wolf–Rayet stars. Of the objects in the imaging region, all are recovered in the images. The timescale for stellar disappearance is set by the free-fall time, which is a function of the stellar radius. Our observations at 4 and 13 days after the event result in a search sensitive to objects of up to about 200 solar radii. We conclude that it is unlikely that GW150914 was caused by the core collapse of a relatively compact supergiant in the LMC, consistent with the LIGO Collaboration analyses of the gravitational waveform as best interpreted as a high mass binary black hole merger. We discuss how to generalize this search for future very nearby core-collapse candidates.
Annis, J.; Soares-Santos, M.; Berger, E.; Brout, D.; Chen, H.; Chornock, R.; Cowperthwaite, P. S.; Diehl, H. T.; Doctor, Z.; Cenko, S. B.
2016-01-01
The collapse of a stellar core is expected to produce gravitational waves (GWs), neutrinos, and in most cases a luminous supernova. Sometimes, however, the optical event could be significantly less luminous than a supernova and a direct collapse to a black hole, where the star just disappears, is possible. The GW event GW150914 was detected by the LIGO Virgo Collaboration via a burst analysis that gave localization contours enclosing the Large Magellanic Cloud (LMC). Shortly thereafter, we used DECam to observe 102 deg(exp.2) of the localization area,including 38 deg(exp. 2) on the LMC for a missing supergiant search. We construct a complete catalog of LMC luminous red supergiants, the best candidates to undergo invisible core collapse, and collected catalogs of other candidates:less luminous red supergiants, yellow supergiants, blue supergiants, luminous blue variable stars, and Wolf-Rayet stars. Of the objects in the imaging region, all are recovered in the images. The timescale for stellar disappearance is set by the free-fall time, which is a function of the stellar radius. Our observations at 4 and 13 days after the event result in a search sensitive to objects of up to about 200 solar radii. We conclude that it is unlikely that GW150914 was caused by the core collapse of a relatively compact supergiant in the LMC, consistent with the LIGO Collaboration analyses of the gravitational waveform as best interpreted as a high mass binary black hole merger. We discuss how to generalize this search for future very nearby core-collapse candidates.
Merger of Multiple Accreting Black Holes Concordant with Gravitational-wave Events
Tagawa, Hiromichi; Umemura, Masayuki
2018-03-01
Recently, the advanced Laser Interferometer Gravitational-Wave Observatory (aLIGO) has detected black hole (BH) merger events, most of which are sourced by BHs more massive than 30 M ⊙. Especially, the observation of GW170104 suggests dynamically assembled binaries favoring a distribution of misaligned spins. It has been argued that mergers of unassociated BHs can be engendered through a chance meeting in a multiple BH system under gas-rich environments. In this paper, we consider the merger of unassociated BHs, concordant with the massive BH merger events. To that end, we simulate a multiple BH system with a post-Newtonian N-body code incorporating gas accretion and general relativistic effects. As a result, we find that gas dynamical friction effectively promotes a three-body interaction of BHs in dense gas of n gas ≳ 106 cm‑3, so that BH mergers can take place within 30 Myr. This scenario predicts an isotropic distribution of spin tilts. In the concordant models with GW150914, the masses of seed BHs are required to be ≳25 M ⊙. The potential sites of such chance meeting BH mergers are active galactic nucleus (AGN) disks and dense interstellar clouds. Assuming the LIGO O1, we roughly estimate the event rates for PopI BHs and PopIII BHs in AGN disks to be ≃1–2 yr‑1 and ≃1 yr‑1, respectively. Multiple episodes of AGNs may enhance the rates by roughly an order of magnitude. For massive PopI BHs in dense interstellar clouds the rate is ≃0.02 yr‑1. Hence, high-density AGN disks are a more plausible site for mergers of chance meeting BHs.
A SEARCH FOR AN OPTICAL COUNTERPART TO THE GRAVITATIONAL-WAVE EVENT GW151226
Energy Technology Data Exchange (ETDEWEB)
Smartt, S. J.; Smith, K. W.; Young, D. R.; Inserra, C.; Wright, D. E.; Jerkstrand, A.; Maguire, K.; Mueller, B. [Astrophysics Research Centre, School of Mathematics and Physics, Queens University Belfast, Belfast BT7 1NN (United Kingdom); Chambers, K. C.; Huber, M. E.; Denneau, L.; Flewelling, H.; Heinze, A.; Magnier, E. A.; Sherstyuk, A.; Stalder, B.; Schultz, A. S. B. [Institute of Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Chen, T.-W. [Max-Planck-Institut für Extraterrestrische Physik, Giessenbachstraße 1, D-85748, Garching (Germany); Coughlin, M. [Department of Physics, Harvard University, Cambridge, MA 02138 (United States); Rest, A., E-mail: s.smartt@qub.ac.uk [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); and others
2016-08-20
We present a search for an electromagnetic counterpart of the gravitational-wave source GW151226. Using the Pan-STARRS1 telescope we mapped out 290 square degrees in the optical i {sub P1} filter, starting 11.5 hr after the LIGO information release and lasting for an additional 28 days. The first observations started 49.5 hr after the time of the GW151226 detection. We typically reached sensitivity limits of i {sub P1} = 20.3–20.8 and covered 26.5% of the LIGO probability skymap. We supplemented this with ATLAS survey data, reaching 31% of the probability region to shallower depths of m ≃ 19. We found 49 extragalactic transients (that are not obviously active galactic nuclei), including a faint transient in a galaxy at 7 Mpc (a luminous blue variable outburst) plus a rapidly decaying M-dwarf flare. Spectral classification of 20 other transient events showed them all to be supernovae. We found an unusual transient, PS15dpn, with an explosion date temporally coincident with GW151226, that evolved into a type Ibn supernova. The redshift of the transient is secure at z = 0.1747 ± 0.0001 and we find it unlikely to be linked, since the luminosity distance has a negligible probability of being consistent with that of GW151226. In the 290 square degrees surveyed we therefore do not find a likely counterpart. However we show that our survey strategy would be sensitive to NS–NS mergers producing kilonovae at D{sub L} ≲ 100 Mpc, which is promising for future LIGO/Virgo searches.
Techniques for Targeted Fermi-GBM Follow-Up of Gravitational-Wave Events
Blackburn, L.; Camp, J.; Briggs, M. S.; Connaughton, V.; Jenke, P.; Christensen, N.; Veitch, J.
2012-01-01
The Advanced LIGO and Advanced Virgo ground-based gravitational-wave (GW) detectors are projected to come online 2015 2016, reaching a final sensitivity sufficient to observe dozens of binary neutron star mergers per year by 2018. We present a fully-automated, targeted search strategy for prompt gamma-ray counterparts in offline Fermi-GBM data. The multi-detector method makes use of a detailed model response of the instrument, and benefits from time and sky location information derived from the gravitational-wave signal.
International Nuclear Information System (INIS)
Palenzuela, Carlos; Lehner, Luis; Yoshida, Shin
2010-01-01
In addition to producing loud gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as an enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves.
International Nuclear Information System (INIS)
Melchior, Anne-Laure
1995-01-01
This work is involved in baryonic dark matter search in galactic halos. An important collect of observational data has been initiated to test the hypothesis that this dark mass is made of compact objects such as brown dwarfs or small mass stars. The gravitational microlensing effect allows to probe this distribution of this mass type along the line of sight of nearby galaxies such as the Large Magellanic Cloud. A new way to detect these microlensing events has been proposed by P. Baillon et al.: the pixel method. The aim is to detect the amplification of stars which are unresolved or too faint to be seen by classical analysis. First, we present this method and the simulations which allow to establish its feasibility. Then, we describe the pixel analysis of the 91-92 EROS data on the Large Magellanic Cloud. The selection of luminosity variations with a shape compatible with microlensing events allows us to study the sensitivity of this analysis. We see how these results allow us to validate the pixel method applied on a large volume of data. This also shows the possibility to find luminosity variations which escape classical analysis research. Strengthened by these results, we finally describe the analysis of the AGAPE 94 data on the Andromeda galaxy which uses the same pixel method. Being ten times farther away than the Large Magellanic Cloud, the Andromeda galaxy has very few resolved stars, making the pixel method the only way of looking for microlensing events. (author) [fr
Geographic and Annual Influences on Optical Follow-up of Gravitational Wave Events
Energy Technology Data Exchange (ETDEWEB)
Srivastava, Varun [Indian Institute of Science Education and Research Pune, Dr. Homi Bhabha Road, Pashan, Pune 411008 (India); Bhalerao, Varun; Bose, Sukanta [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India); Ravi, Aravind P. [Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741252 (India); Ghosh, Archisman, E-mail: varun.srivastava@students.iiserpune.ac.in [International Centre for Theoretical Sciences, Tata Institute of Fundamental Research, Survey No. 151, Shivakote, Hesaraghatta Hobli, Bengaluru North 560089 (India)
2017-03-20
We investigate the effects of observatory location on the probability of discovering optical/infrared (OIR) counterparts of gravitational wave sources. We show that, for the LIGO–Virgo network, the odds of discovering OIR counterparts show some latitude dependence. A stronger effect is seen to arise from the timing of LIGO–Virgo observing runs during the year, with northern OIR observatories having a better chance of finding the counterparts in northern winters. Assuming identical technical capabilities, the tentative mid-2017 three-detector network observing run favors southern OIR observatories for the discovery of electromagnetic counterparts.
Geographic and Annual Influences on Optical Follow-up of Gravitational Wave Events
International Nuclear Information System (INIS)
Srivastava, Varun; Bhalerao, Varun; Bose, Sukanta; Ravi, Aravind P.; Ghosh, Archisman
2017-01-01
We investigate the effects of observatory location on the probability of discovering optical/infrared (OIR) counterparts of gravitational wave sources. We show that, for the LIGO–Virgo network, the odds of discovering OIR counterparts show some latitude dependence. A stronger effect is seen to arise from the timing of LIGO–Virgo observing runs during the year, with northern OIR observatories having a better chance of finding the counterparts in northern winters. Assuming identical technical capabilities, the tentative mid-2017 three-detector network observing run favors southern OIR observatories for the discovery of electromagnetic counterparts.
International Nuclear Information System (INIS)
Jeong, J.; Park, H.; Han, C.; Gould, A.; Poleski, R.; Udalski, A.; Szymański, M. K.; Pietrzyński, G.; Soszyński, I.; Ulaczyk, K.; Wyrzykowski, Ł.; Abe, F.; Fukunaga, D.; Itow, Y.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Freeman, M.; Fukui, A.; Koshimoto, N.
2015-01-01
We reanalyze microlensing events in the published list of anomalous events that were observed from the Optical Gravitational Lensing Experiment (OGLE) lensing survey conducted during the 2004–2008 period. In order to check the existence of possible degenerate solutions and extract extra information, we conduct analyses based on combined data from other survey and follow-up observation and consider higher-order effects. Among the analyzed events, we present analyses of eight events for which either new solutions are identified or additional information is obtained. We find that the previous binary-source interpretations of five events are better interpreted by binary-lens models. These events include OGLE-2006-BLG-238, OGLE-2007-BLG-159, OGLE-2007-BLG-491, OGLE-2008-BLG-143, and OGLE-2008-BLG-210. With additional data covering caustic crossings, we detect finite-source effects for six events including OGLE-2006-BLG-215, OGLE-2006-BLG-238, OGLE-2006-BLG-450, OGLE-2008-BLG-143, OGLE-2008-BLG-210, and OGLE-2008-BLG-513. Among them, we are able to measure the Einstein radii of three events for which multi-band data are available. These events are OGLE-2006-BLG-238, OGLE-2008-BLG-210, and OGLE-2008-BLG-513. For OGLE-2008-BLG-143, we detect higher-order effects induced by the changes of the observer’s position caused by the orbital motion of the Earth around the Sun. In addition, we present degenerate solutions resulting from the known close/wide or ecliptic degeneracy. Finally, we note that the masses of the binary companions of the lenses of OGLE-2006-BLG-450 and OGLE-2008-BLG-210 are in the brown-dwarf regime
Energy Technology Data Exchange (ETDEWEB)
Jeong, J.; Park, H.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Gould, A.; Poleski, R. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Udalski, A.; Szymański, M. K.; Pietrzyński, G.; Soszyński, I.; Ulaczyk, K.; Wyrzykowski, Ł. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Abe, F.; Fukunaga, D.; Itow, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya, 464-8601 (Japan); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556-5670 (United States); Bond, I. A. [Institute of Information and Mathematical Sciences, Massey University, Private Bag 102-904, North Shore Mail Centre, Auckland (New Zealand); Botzler, C. S.; Freeman, M. [Department of Physics, University of Auckland, Private Bag 92-019, Auckland 1001 (New Zealand); Fukui, A. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Asakuchi, Okayama 719-0232 (Japan); Koshimoto, N. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Collaboration: (The OGLE Collaboration); (The MOA Collaboration); (The PLANET Collaboration); (The μFUN Collaboration); (The RoboNet Collaboration); and others
2015-05-01
We reanalyze microlensing events in the published list of anomalous events that were observed from the Optical Gravitational Lensing Experiment (OGLE) lensing survey conducted during the 2004–2008 period. In order to check the existence of possible degenerate solutions and extract extra information, we conduct analyses based on combined data from other survey and follow-up observation and consider higher-order effects. Among the analyzed events, we present analyses of eight events for which either new solutions are identified or additional information is obtained. We find that the previous binary-source interpretations of five events are better interpreted by binary-lens models. These events include OGLE-2006-BLG-238, OGLE-2007-BLG-159, OGLE-2007-BLG-491, OGLE-2008-BLG-143, and OGLE-2008-BLG-210. With additional data covering caustic crossings, we detect finite-source effects for six events including OGLE-2006-BLG-215, OGLE-2006-BLG-238, OGLE-2006-BLG-450, OGLE-2008-BLG-143, OGLE-2008-BLG-210, and OGLE-2008-BLG-513. Among them, we are able to measure the Einstein radii of three events for which multi-band data are available. These events are OGLE-2006-BLG-238, OGLE-2008-BLG-210, and OGLE-2008-BLG-513. For OGLE-2008-BLG-143, we detect higher-order effects induced by the changes of the observer’s position caused by the orbital motion of the Earth around the Sun. In addition, we present degenerate solutions resulting from the known close/wide or ecliptic degeneracy. Finally, we note that the masses of the binary companions of the lenses of OGLE-2006-BLG-450 and OGLE-2008-BLG-210 are in the brown-dwarf regime.
Maximilien Brice
2012-01-01
Signature of the CERN – EGO (European Gravitational Observatory) Agreement concerning Collaboration in Scientific, Technological, Educational and other Domains of Mutual Interest, by R. Heuer, Director-General and Prof. F. Ferrini.
Optical Follow-up of Gravitational-wave Events with Las Cumbres Observatory
Energy Technology Data Exchange (ETDEWEB)
Arcavi, Iair; McCully, Curtis; Hosseinzadeh, Griffin; Howell, D. Andrew; Vasylyev, Sergiy [Department of Physics, University of California, Santa Barbara, CA 93106-9530 (United States); Poznanski, Dovi; Zaltzman, Michael; Maoz, Dan [Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978 (Israel); Singer, Leo [Joint Space-Science Institute, University of Maryland, College Park, MD 20742 (United States); Valenti, Stefano [Department of Physics, University of California, 1 Shields Avenue, Davis, CA 95616-5270 (United States); Kasen, Daniel [Nuclear Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8169 (United States); Barnes, Jennifer [Columbia Astrophysics Laboratory, Columbia University, New York, NY, 10027 (United States); Piran, Tsvi [Racah Institute of Physics, The Hebrew University of Jerusalem, Jerusalem 91904 (Israel); Fong, Wen-fai, E-mail: arcavi@ucsb.edu [CIERA and Department of Physics and Astronomy, Northwestern University 2145 Sheridan Road, Evanston, IL 60208 (United States)
2017-10-20
We present an implementation of the Gehrels et al. galaxy-targeted strategy for gravitational-wave (GW) follow-up using the Las Cumbres Observatory global network of telescopes. We use the Galaxy List for the Advanced Detector Era (GLADE) galaxy catalog, which we show is complete (with respect to a Schechter function) out to ∼300 Mpc for galaxies brighter than the median Schechter function galaxy luminosity. We use a prioritization algorithm to select the galaxies with the highest chance of containing the counterpart given their luminosity, their position, and their distance relative to a GW localization, and in which we are most likely to detect a counterpart given its expected brightness compared to the limiting magnitude of our telescopes. This algorithm can be easily adapted to any expected transient parameters and telescopes. We implemented this strategy during the second Advanced Detector Observing Run (O2) and followed the black hole merger GW170814 and the neutron star merger GW170817. For the latter, we identified an optical kilonova/macronova counterpart thanks to our algorithm selecting the correct host galaxy fifth in its ranked list among the 182 galaxies we identified in the Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo localization. This also allowed us to obtain some of the earliest observations of the first optical transient ever triggered by a GW detection (as presented in a companion paper).
Optical Follow-up of Gravitational-wave Events with Las Cumbres Observatory
Arcavi, Iair; McCully, Curtis; Hosseinzadeh, Griffin; Howell, D. Andrew; Vasylyev, Sergiy; Poznanski, Dovi; Zaltzman, Michael; Maoz, Dan; Singer, Leo; Valenti, Stefano; Kasen, Daniel; Barnes, Jennifer; Piran, Tsvi; Fong, Wen-fai
2017-10-01
We present an implementation of the Gehrels et al. galaxy-targeted strategy for gravitational-wave (GW) follow-up using the Las Cumbres Observatory global network of telescopes. We use the Galaxy List for the Advanced Detector Era (GLADE) galaxy catalog, which we show is complete (with respect to a Schechter function) out to ˜300 Mpc for galaxies brighter than the median Schechter function galaxy luminosity. We use a prioritization algorithm to select the galaxies with the highest chance of containing the counterpart given their luminosity, their position, and their distance relative to a GW localization, and in which we are most likely to detect a counterpart given its expected brightness compared to the limiting magnitude of our telescopes. This algorithm can be easily adapted to any expected transient parameters and telescopes. We implemented this strategy during the second Advanced Detector Observing Run (O2) and followed the black hole merger GW170814 and the neutron star merger GW170817. For the latter, we identified an optical kilonova/macronova counterpart thanks to our algorithm selecting the correct host galaxy fifth in its ranked list among the 182 galaxies we identified in the Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo localization. This also allowed us to obtain some of the earliest observations of the first optical transient ever triggered by a GW detection (as presented in a companion paper).
Energy Technology Data Exchange (ETDEWEB)
Blackburn, L.; Camp, J. [NASA/Goddard Space Flight Center, Greenbelt, MD (United States); Briggs, M. S.; Connaughton, V.; Jenke, P. [University of Alabama in Huntsville, Huntsville, AL (United States); Christensen, N. [Carleton College, Northfield, MN (United States); Remillard, R. A. [Massachussetts Institute of Technology, Cambridge, MA (United States); Veitch, J. [University of Birmingham, Birmingham (United Kingdom)
2015-03-15
We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterparts in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15–20%.
Blackburn, L.; Briggs, M. S.; Camp, J.; Christensen, N.; Connaughton, V.; Jenke, P.; Remillard, R. A.; Veitch, J.
2015-01-01
We present two different search methods for electromagnetic counterparts to gravitational-wave (GW) events from ground-based detectors using archival NASA high-energy data from the Fermi Gamma-ray Burst Monitor (GBM) and RXTE All-sky Monitor (ASM) instruments. To demonstrate the methods, we use a limited number of representative GW background noise events produced by a search for binary neutron star coalescence over the last two months of the LIGO-Virgo S6/VSR3 joint science run. Time and sky location provided by the GW data trigger a targeted search in the high-energy photon data. We use two custom pipelines: one to search for prompt gamma-ray counterparts in GBM, and the other to search for a variety of X-ray afterglow model signals in ASM. We measure the efficiency of the joint pipelines to weak gamma-ray burst counterparts, and a family of model X-ray afterglows. By requiring a detectable signal in either electromagnetic instrument coincident with a GW event, we are able to reject a large majority of GW candidates. This reduces the signal-to-noise ratio of the loudest surviving GW background event by around 15-20 percent.
Shin, I.-G.; Han, C.; Choi, J.-Y.; Hwang, K.-H.; Jung, Y.-K.; Park, H.
2015-04-01
High-magnification gravitational microlensing events provide an important channel of detecting planetary systems with multiple giants located at their birth places. In order to investigate the potential existence of additional planets, we reanalyze the light curves of the eight high-magnification microlensing events, for each of which a single planet was previously detected. The analyzed events include OGLE-2005-BLG-071, OGLE-2005-BLG-169, MOA-2007-BLG-400, MOA-2008-BLG-310, MOA-2009-BLG-319, MOA-2009-BLG-387, MOA-2010-BLG-477, and MOA-2011-BLG-293. We find that including an additional planet improves fits with {Δ }{{χ }2}\\lt 80 for seven out of eight analyzed events. For MOA-2009-BLG-319, the improvement is relatively big with {Δ }{{χ }2}∼ 143. From inspection of the fits, we find that the improvement of the fits is attributed to systematics in data. Although no clear evidence of additional planets is found, it is still possible to constrain the existence of additional planets in the parameter space. For this purpose, we construct exclusion diagrams showing the confidence levels excluding the existence of an additional planet as a function of its separation and mass ratio. We also present the exclusion ranges of additional planets with 90% confidence level for Jupiter-, Saturn-, and Uranus-mass planets.
DEFF Research Database (Denmark)
Savchenko, V.; Ferrigno, C.; Kuulkers, E.
2017-01-01
We report the INTernational Gamma-ray Astrophysics Laboratory (INTEGRAL) detection of the short gamma-ray burst GRB 170817A (discovered by Fermi-GBM) with a signal-to-noise ratio of 4.6, and, for the first time, its association with the gravitational waves (GWs) from binary neutron star (BNS......) merging event GW170817 detected by the LIGO and Virgo observatories. The significance of association between the gamma-ray burst observed by INTEGRAL and GW170817 is 3.2σ, while the association between the Fermi-GBM and INTEGRAL detections is 4.2σ. GRB 170817A was detected by the SPI-ACS instrument about...
Indik, Nathaniel; Haris, K.; Dal Canton, Tito; Fehrmann, Henning; Krishnan, Badri; Lundgren, Andrew; Nielsen, Alex B.; Pai, Archana
2017-01-01
Gravitational wave searches to date have largely focused on non-precessing systems. Including precession effects greatly increases the number of templates to be searched over. This leads to a corresponding increase in the computational cost and can increase the false alarm rate of a realistic search. On the other hand, there might be astrophysical systems that are entirely missed by non-precessing searches. In this paper we consider the problem of constructing a template bank using stochastic methods for neutron star-black hole binaries allowing for precession, but with the restrictions that the total angular momentum of the binary is pointing toward the detector and that the neutron star spin is negligible relative to that of the black hole. We quantify the number of templates required for the search, and we explicitly construct the template bank. We show that despite the large number of templates, stochastic methods can be adapted to solve the problem. We quantify the parameter space region over which the non-precessing search might miss signals.
International Nuclear Information System (INIS)
Albert, A.; Drouhin, D.; Racca, C.; Andre, M.; Anghinolfi, M.; Anton, G.; Eberl, T.; Graf, K.; Hallmann, S.; Hoessl, J.; Hofestaedt, J.; James, C.W.; Kalekin, O.; Katz, U.; Kiessling, D.; Lahmann, R.; Sieger, C.; Ardid, M.; Felis, I.; Martinez-Mora, J.A.; Saldana, M.; Aubert, J.J.; Bertin, V.; Brunner, J.; Busto, J.; Carr, J.; Costantini, H.; Coyle, P.; Dornic, D.; Enzenhoefer, A.; Quinn, L.; Salvadori, I.; Turpin, D.; Avgitas, T.; Baret, B.; Bourret, S.; Coelho, J.A.B.; Creusot, A.; Gregoire, T.; Gracia Ruiz, R.; Lachaud, C.; Barrios-Marti, J.; Hernandez-Rey, J.J.; Illuminati, G.; Lotze, M.; Toennis, C.; Zornoza, J.D.; Zuniga, J.; Basa, S.; Marcelin, M.; Nezri, E.; Belhorma, B.; Biagi, S.; Coniglione, R.; Distefano, C.; Piattelli, P.; Riccobene, G.; Sapienza, P.; Trovato, A.; Bormuth, R.; Jong, M. de; Samtleben, D.F.E.; Bouwhuis, M.C.; Heijboer, A.J.; Jongen, M.; Michael, T.; Branzas, H.; Caramete, L.; Pavalas, G.E.; Popa, V.; Bruijn, R.; Melis, K.; Capone, A.; Di Palma, I.; Perrina, C.; Vizzoca, A.; Celli, S.; Cherkaoui El Moursli, R.; El Khayati, N.; Ettahiri, A.; Fassi, F.; Tayalati, Y.; Chiarusi, T.; Circella, M.; Sanchez-Losa, A.; Coleiro, A.; Diaz, A.F.; Deschamps, A.; Hello, Y.; De Bonis, G.; Domi, A.; Hugon, C.; Sanguineti, M.; Taiuti, M.; Donzaud, C.; El Bojaddaini, I.; Moussa, A.; Elsaesser, D.; Kadler, M.; Kreter, M.; Fusco, L.A.; Margiotta, A.; Pellegrino, C.; Spurio, M.; Versari, F.; Gay, P.; Giordano, V.; Glotin, H.; Haren, H. van; Kouchner, A.; Van Elewyck, V.; Kreykenbohm, I.; Wilms, J.; Kulikovskiy, V.; Lefevre, D.; Leonora, E.; Loucatos, S.; Vallage, B.; Marinelli, A.; Mele, R.; Vivolo, D.; Migliozzi, P.; Navas, S.; Organokov, M.; Pradier, T.; Schuessler, F.; Stolarczyk, T.
2017-01-01
Advanced LIGO detected a significant gravitational wave signal (GW170104) originating from the coalescence of two black holes during the second observation run on January 4th, 2017. An all-sky high-energy neutrino follow-up search has been made using data from the Antares neutrino telescope, including both upgoing and downgoing events in two separate analyses. No neutrino candidates were found within ±500 s around the GW event time nor any time clustering of events over an extended time window of ±3 months. The non-detection is used to constrain isotropic-equivalent high-energy neutrino emission from GW170104 to less than ∝ 1.2 x 10 55 erg for a E -2 spectrum. This constraint is valid in the energy range corresponding to the 5-95% quantiles of the neutrino flux [3.2 TeV; 3.6 PeV], if the GW emitter was below the Antares horizon at the alert time. (orig.)
International Nuclear Information System (INIS)
Tomizawa, Shinya; Siino, Masaru
2006-01-01
We investigated the relation between the behaviour of gravitational waves at late time and the limit structure of future null infinity tangent which will determine the topology of the event horizon far in the future. In the present paper, we mainly consider a spacetime with two black holes. Although in most cases, the black holes coalesce and the event horizon is topologically a single sphere far in the future, there are several possibilities that the black holes never coalesce and such exact solutions as examples. In our formulation, the tangent vector of future null infinity is, under conformal embedding, related to the number of black holes far in the future through the Poincare-Hopf theorem. Under the conformal embedding, the topology of the event horizon far in the future will be affected by the geometrical structure of the future null infinity. In this paper, we relate the behaviour of Weyl curvature to this limit behaviour of the generator vector of the future null infinity. We show if Weyl curvature decays sufficiently slowly at late time in the neighbourhood of future null infinity, two black holes never coalesce
Energy Technology Data Exchange (ETDEWEB)
Albert, A.; Drouhin, D.; Racca, C. [Universite de Haute Alsace - Institut Universitaire de Technologie de Colmar, GRPHE, Colmar (France); Andre, M. [Technical University of Catalonia, Laboratory of Applied Bioacoustics, Vilanova i la Geltru, Barcelona (Spain); Anghinolfi, M. [INFN-Sezione di Genova, Genoa (Italy); Anton, G.; Eberl, T.; Graf, K.; Hallmann, S.; Hoessl, J.; Hofestaedt, J.; James, C.W.; Kalekin, O.; Katz, U.; Kiessling, D.; Lahmann, R.; Sieger, C. [Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen Centre for Astroparticle Physics, Erlangen (Germany); Ardid, M.; Felis, I.; Martinez-Mora, J.A.; Saldana, M. [Universitat Politecnica de Valencia, Institut d' Investigacio per a la Gestio Integrada de les Zones Costaneres (IGIC), Gandia (Spain); Aubert, J.J.; Bertin, V.; Brunner, J.; Busto, J.; Carr, J.; Costantini, H.; Coyle, P.; Dornic, D.; Enzenhoefer, A.; Quinn, L.; Salvadori, I.; Turpin, D. [Aix Marseille Univ., CNRS/IN2P3, CPPM, Marseille (France); Avgitas, T.; Baret, B.; Bourret, S.; Coelho, J.A.B.; Creusot, A.; Gregoire, T.; Gracia Ruiz, R.; Lachaud, C. [Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, APC, Paris (France); Barrios-Marti, J.; Hernandez-Rey, J.J.; Illuminati, G.; Lotze, M.; Toennis, C.; Zornoza, J.D.; Zuniga, J. [IFIC-Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Paterna, Valencia (Spain); Basa, S.; Marcelin, M.; Nezri, E. [Pole de l' Etoile Site de Chateau-Gombert, LAM-Laboratoire d' Astrophysique de Marseille (France); Belhorma, B. [National Center for Energy Sciences and Nuclear Techniques, Rabat (Morocco); Biagi, S.; Coniglione, R.; Distefano, C.; Piattelli, P.; Riccobene, G.; Sapienza, P.; Trovato, A. [INFN-Laboratori Nazionali del Sud (LNS), Catania (Italy); Bormuth, R.; Jong, M. de; Samtleben, D.F.E. [Nikhef, Amsterdam (Netherlands); Universiteit Leiden, Huygens-Kamerlingh Onnes Laboratorium, Leiden (Netherlands); Bouwhuis, M.C.; Heijboer, A.J.; Jongen, M.; Michael, T. [Nikhef, Amsterdam (Netherlands); Branzas, H.; Caramete, L.; Pavalas, G.E.; Popa, V. [Institute for Space Science, Bucharest (Romania); Bruijn, R.; Melis, K. [Nikhef, Amsterdam (Netherlands); Universiteit van Amsterdam, Instituut voor Hoge-Energie Fysica, Amsterdam (Netherlands); Capone, A.; Di Palma, I.; Perrina, C.; Vizzoca, A. [INFN-Sezione di Roma, Rome (Italy); Dipartimento di Fisica dell' Universita La Sapienza, Rome (Italy); Celli, S. [INFN-Sezione di Roma, Rome (Italy); Dipartimento di Fisica dell' Universita La Sapienza, Rome (Italy); Gran Sasso Science Institute, L' Aquila (Italy); Cherkaoui El Moursli, R.; El Khayati, N.; Ettahiri, A.; Fassi, F.; Tayalati, Y. [University Mohammed V, Faculty of Sciences, Rabat (Morocco); Chiarusi, T. [INFN-Sezione di Bologna, Bologna (Italy); Circella, M.; Sanchez-Losa, A. [INFN-Sezione di Bari, Bari (Italy); Coleiro, A. [Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, APC, Paris (France); IFIC-Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Paterna, Valencia (Spain); Diaz, A.F. [University of Granada, Department of Computer Architecture and Technology/CITIC, Granada (Spain); Deschamps, A.; Hello, Y. [Geoazur, UCA, CNRS, IRD, Observatoire de la Cote d' Azur, Sophia Antipolis (France); De Bonis, G. [Dipartimento di Fisica dell' Universita La Sapienza, Rome (Italy); Domi, A.; Hugon, C.; Sanguineti, M.; Taiuti, M. [INFN-Sezione di Genova, Genoa (Italy); Dipartimento di Fisica dell' Universita, Genoa (Italy); Donzaud, C. [Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, APC, Paris (France); Universite Paris-Sud, Orsay (France); El Bojaddaini, I.; Moussa, A. [University Mohammed I, Laboratory of Physics of Matter and Radiations, Oujda (Morocco); Elsaesser, D.; Kadler, M.; Kreter, M. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, Wuerzburg (Germany); Fusco, L.A.; Margiotta, A.; Pellegrino, C.; Spurio, M.; Versari, F. [INFN-Sezione di Bologna, Bologna (Italy); Dipartimento di Fisica e Astronomia dell' Universita, Bologna (Italy); Gay, P. [Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, APC, Paris (France); Clermont Universite, Universite Blaise Pascal, Laboratoire de Physique Corpusculaire, CNRS/IN2P3, Clermont-Ferrand (France); Giordano, V. [INFN-Sezione di Catania, Catania (Italy); Glotin, H. [LSIS, Aix Marseille Universite CNRS ENSAM LSIS UMR 7296, Marseille (France); Universite de Toulon CNRS LSIS UMR 7296, La Garde (FR); Institut Universitaire de France, Paris (FR); Haren, H. van [Utrecht University, Royal Netherlands Institute for Sea Research (NIOZ), ' t Horntje (Texel) (NL); Kouchner, A.; Van Elewyck, V. [Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, APC, Paris (FR); Institut Universitaire de France, Paris (FR); Kreykenbohm, I.; Wilms, J. [Universitaet Erlangen-Nuernberg, Dr. Remeis-Sternwarte and ECAP, Bamberg (DE); Kulikovskiy, V. [Aix Marseille Univ., CNRS/IN2P3, CPPM, Marseille (FR); Moscow State University, Skobeltsyn Institute of Nuclear Physics, Moscow (RU); Lefevre, D. [Aix-Marseille University, Mediterranean Institute of Oceanography (MIO), Marseille (FR); Universite du Sud Toulon-Var, CNRS-INSU/IRD UM 110, La Garde (FR); Leonora, E. [INFN-Sezione di Catania, Catania (IT); Dipartimento di Fisica e Astronomia dell' Universita, Catania (IT); Loucatos, S.; Vallage, B. [Univ Paris Diderot, CNRS/IN2P3, CEA/Irfu, Obs de Paris, Sorbonne Paris Cite, APC, Paris (FR); Direction des Sciences de la Matiere-Institut de Recherche sur les Lois Fondamentales de l' Univers-Service de Physique des Particules, CEA Saclay, Gif-sur-Yvette (FR); Marinelli, A. [INFN-Sezione di Pisa, Pisa (IT); Dipartimento di Fisica dell' Universita, Pisa (IT); Mele, R.; Vivolo, D. [INFN-Sezione di Napoli, Naples (IT); Dipartimento di Fisica dell' Universita Federico II di Napoli, Naples (IT); Migliozzi, P. [INFN-Sezione di Napoli, Naples (IT); Navas, S. [University of Granada, Dept. de Fisica Teorica y del Cosmos y C.A.F.P.E., Granada (ES); Organokov, M.; Pradier, T. [Universite de Strasbourg, CNRS, Strasbourg (FR); Schuessler, F.; Stolarczyk, T. [Direction des Sciences de la Matiere-Institut de Recherche sur les Lois Fondamentales de l' Univers-Service de Physique des Particules, CEA Saclay, Gif-sur-Yvette (FR); Collaboration: The ANTARES Collaboration
2017-12-15
Advanced LIGO detected a significant gravitational wave signal (GW170104) originating from the coalescence of two black holes during the second observation run on January 4th, 2017. An all-sky high-energy neutrino follow-up search has been made using data from the Antares neutrino telescope, including both upgoing and downgoing events in two separate analyses. No neutrino candidates were found within ±500 s around the GW event time nor any time clustering of events over an extended time window of ±3 months. The non-detection is used to constrain isotropic-equivalent high-energy neutrino emission from GW170104 to less than ∝ 1.2 x 10{sup 55} erg for a E{sup -2} spectrum. This constraint is valid in the energy range corresponding to the 5-95% quantiles of the neutrino flux [3.2 TeV; 3.6 PeV], if the GW emitter was below the Antares horizon at the alert time. (orig.)
Gravitational Waves: An Entirely New Window onto the Cosmos
CERN. Geneva
2017-01-01
On September 14, 2015, scientists from the LIGO Scientific Collaboration and the Virgo Collaboration using the LIGO detectors observed the collision and fusion of two black holes by directly measuring the gravitational waves emitted during their collision. This detection came almost exactly 100 years after Einstein developed his revolutionary general theory of relativity that predicted their existence, and 50 years after scientists began searching for them in earnest. Since then, two more gravitational-wave events have been confidently detected. These discoveries have truly profound implications for physics and astronomy. Gravitational waves provide unique information on the most energetic astrophysical events, revealing unique insights into the nature of gravity, matter, space, and time. LIGO has opened a new window onto the cosmos. I will talk about how we made the detection and discuss how gravitational wave astronomy promises to change our understanding o...
First Electromagnetic Pulse Associated with a Gravitational-wave Event: Profile, Duration, and Delay
Lin, Da-Bin; Liu, Tong; Lin, Jie; Wang, Xiang-Gao; Gu, Wei-Min; Liang, En-Wei
2018-04-01
We study the first electromagnetic (EM) pulse after the gravitational-wave (GW) chirp signal, focusing on its profile and duration. It is found that the light curve, especially the steep decay (SD) phase, can be very different by adopting different viewing angles θ view of the jet shell. For an on-axis jet with a power-law radiation spectrum, the observed flux in the SD is proportional to {t}obs}-2-β with β being the spectral index and t obs being the observer time. Here, t obs = 0 is set at the time we observe the jet being ejected from the central engine. The SD may become steep by increasing θ view. We also study the bolometric luminosity L from a jet shell with a non-power-law radiation spectrum. For an on-axis jet, L ∝ t obs ‑3 is found in the SD. However, the SD is steeper than L\\propto {t}obs}-3 for radiation from an off-axis jet. The higher value of the θ view is, the steeper SD would be. Then, we suggest that the SD phase can be used to discriminate an off-axis jet from an on-axis jet. The reason for the above behaviors is discussed. In addition, we find that the duration of first EM pulse is close to its peak time, especially for θ view ∼ 20°. This result is consistent with that found in GW 170817/GRB 170817A. Thus, the jet corresponding to the prompt emission of GRB 170817A should be ejected immediately after the merger. Our results also reveal that the duration of the first EM pulse can provide information on the time to search for GWs.
RATIR Follow-up of LIGO/Virgo Gravitational Wave Events
Golkhou, V. Zach; Butler, Nathaniel R.; Strausbaugh, Robert; Troja, Eleonora; Kutyrev, Alexander; Lee, William H.; Román-Zúñiga, Carlos G.; Watson, Alan M.
2018-04-01
We have recently witnessed the first multi-messenger detection of colliding neutron stars through gravitational waves (GWs) and electromagnetic (EM) waves (GW 170817) thanks to the joint efforts of LIGO/Virgo and Space/Ground-based telescopes. In this paper, we report on the RATIR follow-up observation strategies and show the results for the trigger G194575. This trigger is not of astrophysical interest; however, it is of great interest to the robust design of a follow-up engine to explore large sky-error regions. We discuss the development of an image-subtraction pipeline for the six-color, optical/NIR imaging camera RATIR. Considering a two-band (i and r) campaign in the fall of 2015, we find that the requirement of simultaneous detection in both bands leads to a factor ∼10 reduction in false alarm rate, which can be further reduced using additional bands. We also show that the performance of our proposed algorithm is robust to fluctuating observing conditions, maintaining a low false alarm rate with a modest decrease in system efficiency that can be overcome utilizing repeat visits. Expanding our pipeline to search for either optical or NIR detections (three or more bands), considering separately the optical riZ and NIR YJH bands, should result in a false alarm rate ≈1% and an efficiency ≈90%. RATIR’s simultaneous optical/NIR observations are expected to yield about one candidate transient in the vast 100 deg2 LIGO error region for prioritized follow-up with larger aperture telescopes.
Allegro: noise performance and the ongoing search for gravitational waves
International Nuclear Information System (INIS)
Heng, I S; Daw, E; Giaime, J; Hamilton, W O; Mchugh, M P; Johnson, W W
2002-01-01
The noise performance of Allegro since 1993 is summarized. We show that the noise level of Allegro is, in general, stationary. Non-Gaussian impulse excitations persist despite efforts to isolate the detector from environmental disturbances. Some excitations are caused by seismic activity and flux jumps in the SQUID. Algorithms to identify and automatically veto these events are presented. Also, the contribution of Allegro to collaborations with other resonant-mass detectors via the International Gravitational Event Collaboration and with LIGO is reviewed
Allegro: noise performance and the ongoing search for gravitational waves
Heng, I S; Giaime, J; Hamilton, W O; McHugh, M P; Johnson, W W
2002-01-01
The noise performance of Allegro since 1993 is summarized. We show that the noise level of Allegro is, in general, stationary. Non-Gaussian impulse excitations persist despite efforts to isolate the detector from environmental disturbances. Some excitations are caused by seismic activity and flux jumps in the SQUID. Algorithms to identify and automatically veto these events are presented. Also, the contribution of Allegro to collaborations with other resonant-mass detectors via the International Gravitational Event Collaboration and with LIGO is reviewed.
Energy Technology Data Exchange (ETDEWEB)
Savchenko, V.; Ferrigno, C.; Bozzo, E.; Courvoisier, T. J.-L. [ISDC, Department of Astronomy, University of Geneva, Chemin d’Écogia, 16 CH-1290 Versoix (Switzerland); Kuulkers, E. [European Space Research and Technology Centre (ESA/ESTEC), Keplerlaan 1, 2201 AZ Noordwijk (Netherlands); Bazzano, A.; Natalucci, L.; Rodi, J. [INAF-Institute for Space Astrophysics and Planetology, Via Fosso del Cavaliere 100, I-00133-Rome (Italy); Brandt, S.; Chenevez, J. [DTU Space, National Space Institute Elektrovej, Building 327 DK-2800 Kongens Lyngby (Denmark); Diehl, R.; Von Kienlin, A. [Max-Planck-Institut für Extraterrestrische Physik, Garching (Germany); Domingo, A. [Centro de Astrobiología (CAB-CSIC/INTA, ESAC Campus), Camino bajo del Castillo S/N, E-28692 Villanueva de la Cañada, Madrid (Spain); Hanlon, L.; Martin-Carrillo, A. [Space Science Group, School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Jourdain, E. [IRAP, Université de Toulouse, CNRS, UPS, CNES, 9 Av. Roche, F-31028 Toulouse (France); Laurent, P.; Lebrun, F. [APC, AstroParticule et Cosmologie, Université Paris Diderot, CNRS/IN2P3, CEA/Irfu, Observatoire de Paris Sorbonne Paris Cité, 10 rue Alice Domont et Léonie Duquet, F-75205 Paris Cedex 13 (France); Lutovinov, A. [Space Research Institute of Russian Academy of Sciences, Profsoyuznaya 84/32, 117997 Moscow (Russian Federation); Mereghetti, S. [INAF, IASF-Milano, via E.Bassini 15, I-20133 Milano (Italy); and others
2017-10-20
We report the INTernational Gamma-ray Astrophysics Laboratory ( INTEGRAL ) detection of the short gamma-ray burst GRB 170817A (discovered by Fermi -GBM) with a signal-to-noise ratio of 4.6, and, for the first time, its association with the gravitational waves (GWs) from binary neutron star (BNS) merging event GW170817 detected by the LIGO and Virgo observatories. The significance of association between the gamma-ray burst observed by INTEGRAL and GW170817 is 3.2σ, while the association between the Fermi -GBM and INTEGRAL detections is 4.2σ. GRB 170817A was detected by the SPI-ACS instrument about 2 s after the end of the GW event. We measure a fluence of (1.4 ± 0.4 ± 0.6) × 10{sup −7} erg cm{sup −2} (75–2000 keV), where, respectively, the statistical error is given at the 1σ confidence level, and the systematic error corresponds to the uncertainty in the spectral model and instrument response. We also report on the pointed follow-up observations carried out by INTEGRAL , starting 19.5 hr after the event, and lasting for 5.4 days. We provide a stringent upper limit on any electromagnetic signal in a very broad energy range, from 3 keV to 8 MeV, constraining the soft gamma-ray afterglow flux to <7.1 × 10{sup −11} erg cm{sup −2} s{sup −1} (80–300 keV). Exploiting the unique capabilities of INTEGRAL , we constrained the gamma-ray line emission from radioactive decays that are expected to be the principal source of the energy behind a kilonova event following a BNS coalescence. Finally, we put a stringent upper limit on any delayed bursting activity, for example, from a newly formed magnetar.
Validation of Monte Carlo event generators in the ATLAS Collaboration for LHC Run 2
The ATLAS collaboration
2016-01-01
This note reviews the main steps followed by the ATLAS Collaboration to validate the properties of particle-level simulated events from Monte Carlo event generators in order to ensure the correctness of all event generator configurations and production samples used in physics analyses. A central validation procedure is adopted which permits the continual validation of the functionality and the performance of the ATLAS event simulation infrastructure. Revisions and updates of the Monte Carlo event generators are also monitored. The methodology behind the validation and tools developed for that purpose, as well as various usage cases, are presented. The strategy has proven to play an essential role in identifying possible problems or unwanted features within a restricted timescale, verifying their origin and pointing to possible bug fixes before full-scale processing is initiated.
Searching gravitational microlensing events in the galaxy spiral arms by EROS II
International Nuclear Information System (INIS)
Derue, Frederic
1999-01-01
The EROS II experiment is searching for microlensing events due to compact massive objects passing through the line-of-sight of luminous stars. These objects are candidates to explain the baryonic component of Dark Matter in our Galaxy. EROS II was dedicated to different lines-of-sight: Small and Large Magellanic Clouds, Galactic Centre and 4 directions towards the Spiral Arms of the Galaxy. This thesis presents the first search for microlensing towards these last lines-of-sight (about 9 million stars). Simple criteria based on the search for significant fluctuations allowed one to discover a low noise sample of 7 candidates to the microlensing effect, with an average timescale of 50 days. A detailed analysis of the light curve of one candidate allows us to give a confidence interval on its mass 2.7 x 10 -3 0 0 = 50 ± 3 days. To improve the knowledge of the distance of the target stars, we have combined observations of EROS II with bibliographic sources on associations of stars linked with the spiral arm features, and we have developed a program to find variable stars. Ten cepheids have thus been found. Distances obtained with different methods are in rough agreement with each other. The average optical depth measured towards the four directions is τ-bar = 0.45 0.11 +0.23 x 10 -6 . It is compatible with expectations from simple galactic models. The long duration of most events favours interpretation of lensing by objects belonging to the disk instead of the halo. It also seems that some events due to bulge lenses have influenced measurements towards the line-of-sight which is closest to the Galactic Centre. Observation continue towards spiral arms. More accurate measurements should be obtained with increase of statistics, allowing one to estimate the disk contribution to the optical depth towards the bulge and the Magellanic Clouds. (author)
Is the Gravitational-Wave Ringdown a Probe of the Event Horizon?
Cardoso, Vitor; Franzin, Edgardo; Pani, Paolo
2016-04-29
It is commonly believed that the ringdown signal from a binary coalescence provides a conclusive proof for the formation of an event horizon after the merger. This expectation is based on the assumption that the ringdown waveform at intermediate times is dominated by the quasinormal modes of the final object. We point out that this assumption should be taken with great care, and that very compact objects with a light ring will display a similar ringdown stage, even when their quasinormal-mode spectrum is completely different from that of a black hole. In other words, universal ringdown waveforms indicate the presence of light rings, rather than of horizons. Only precision observations of the late-time ringdown signal, where the differences in the quasinormal-mode spectrum eventually show up, can be used to rule out exotic alternatives to black holes and to test quantum effects at the horizon scale.
Origin of the heavy elements in binary neutron-star mergers from a gravitational-wave event.
Kasen, Daniel; Metzger, Brian; Barnes, Jennifer; Quataert, Eliot; Ramirez-Ruiz, Enrico
2017-11-02
The cosmic origin of elements heavier than iron has long been uncertain. Theoretical modelling shows that the matter that is expelled in the violent merger of two neutron stars can assemble into heavy elements such as gold and platinum in a process known as rapid neutron capture (r-process) nucleosynthesis. The radioactive decay of isotopes of the heavy elements is predicted to power a distinctive thermal glow (a 'kilonova'). The discovery of an electromagnetic counterpart to the gravitational-wave source GW170817 represents the first opportunity to detect and scrutinize a sample of freshly synthesized r-process elements. Here we report models that predict the electromagnetic emission of kilonovae in detail and enable the mass, velocity and composition of ejecta to be derived from observations. We compare the models to the optical and infrared radiation associated with the GW170817 event to argue that the observed source is a kilonova. We infer the presence of two distinct components of ejecta, one composed primarily of light (atomic mass number less than 140) and one of heavy (atomic mass number greater than 140) r-process elements. The ejected mass and a merger rate inferred from GW170817 imply that such mergers are a dominant mode of r-process production in the Universe.
Soares-Santos, M.; Kessler, R.; Burger, E.; Annis, J.; Brout, D.; Buckley-Geer, E.; Chen, H.; Cowperthwaite, P. S.; Diehl, H.T.; Doctor, Z.;
2016-01-01
We report the results of a deep search for an optical counterpart to the gravitational wave (GW) event GW150914, the first trigger from the Advanced LIGO GW detectors. We used the Dark Energy Camera (DECam) to image a 102 deg(exp 2) area, corresponding to 38% of the initial trigger high-probability sky region and to 11% of the revised high-probability region. We observed in the i and z bands at 4-5, 7, and 24 days after the trigger. The median 5(sigma) point-source limiting magnitudes of our search images are i = 22.5 and z = 21.8 mag. We processed the images through a difference-imaging pipeline using templates from pre-existing Dark Energy Survey data and publicly available DECam data. Due to missing template observations and other losses, our effective search area subtends 40 deg(exp 2), corresponding to a 12% total probability in the initial map and 3% in the final map. In this area, we search for objects that decline significantly between days 4-5 and day 7, and are undetectable by day 24, finding none to typical magnitude limits of i = 21.5, 21.1, 20.1 for object colors (i-z)= 1, 0, -1, respectively. Our search demonstrates the feasibility of a dedicated search program with DECam and bodes well for future research in this emerging field.
Stressful life events as predictors of functioning: findings from the Collaborative Longitudinal Personality Disorders Study
Pagano, M. E.; Skodol, A. E.; Stout, R. L.; Shea, M. T.; Yen, S.; Grilo, C. M.; Sanislow, C. A.; Bender, D. S.; McGlashan, T. H.; Zanarini, M. C.; Gunderson, J. G.
2008-01-01
Objective Although much attention has been given to the effects of adverse childhood experiences on the development of personality disorders (PDs), we know far less about how recent life events influence the ongoing course of functioning. We examined the extent to which PD subjects differ in rates of life events and the extent to which life events impact psychosocial functioning. Method A total of 633 subjects were drawn from the Collaborative Longitudinal Personality Disorders Study (CLPS), a multi-site study of four personality disorders – schizotypal (STPD), borderline (BPD), avoidant (AVPD), obsessive-compulsive (OCPD) – and a comparison group of major depressive disorders (MDD) without PD. Results Borderline personality disorder subjects reported significantly more total negative life events than other PDs or subjects with MDD. Negative events, especially interpersonal events, predicted decreased psychosocial functioning over time. Conclusion Our findings indicate higher rates of negative events in subjects with more severe PDs and suggest that negative life events adversely impact multiple areas of psychosocial functioning. PMID:15521826
Connaughton, V.; Burns, E.; Goldstein, A.; Blackburn, L.; Briggs, M. S.; Christensen, N.; Hui, C. M.; Kocevski, D.; Littenberg, T.; McEnery, J. E.; Racusin, J.; Shawhan, P.; Veitch, J.; Wilson-Hodge, C. A.; Bhat, P. N.; Bissaldi, E.; Cleveland, W.; Giles, M. M.; Gibby, M. H.; von Kienlin, A.; Kippen, R. M.; McBreen, S.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Roberts, O. J.; Stanbro, M.; Veres, P.
2018-01-01
The weak transient detected by the Fermi Gamma-ray Burst Monitor (GBM) 0.4 s after GW150914 has generated much speculation regarding its possible association with the black hole binary merger. Investigation of the GBM data by Connaughton et al. revealed a source location consistent with GW150914 and a spectrum consistent with a weak, short gamma-ray burst. Greiner et al. present an alternative technique for fitting background-limited data in the low-count regime, and call into question the spectral analysis and the significance of the detection of GW150914-GBM presented in Connaughton et al. The spectral analysis of Connaughton et al. is not subject to the limitations of the low-count regime noted by Greiner et al. We find Greiner et al. used an inconsistent source position and did not follow the steps taken in Connaughton et al. to mitigate the statistical shortcomings of their software when analyzing this weak event. We use the approach of Greiner et al. to verify that our original spectral analysis is not biased. The detection significance of GW150914-GBM is established empirically, with a false-alarm rate (FAR) of ∼ {10}-4 Hz. A post-trials false-alarm probability (FAP) of 2.2× {10}-3 (2.9σ ) of this transient being associated with GW150914 is based on the proximity in time to the gravitational-wave event of a transient with that FAR. The FAR and the FAP are unaffected by the spectral analysis that is the focus of Greiner et al.
Shinkai, Hisaaki
2018-01-01
Based on a dynamical formation model of a supermassive black hole (SMBH), we estimate the expected observational profile of gravitational wave at ground-based detectors, such as KAGRA or advanced LIGO/VIRGO. Noting that the second generation of detectors have enough sensitivity from 10 Hz and up, we are able to detect the ring-down gravitational wave of a BH with the mass M 1 per year for ρ = 10. Thus, if we observe a BH with more than 100M⊙ in future gravitational-wave observations, our model naturally explains its source.
Abbott, B. P.; Abbott, R.; Adhikari, R. X.; Ananyeva, A.; Anderson, S. B.; Appert, S.; Arai, K.; Araya, M. C.; Barayoga, J. C.; Barish, B. C.; Berger, B. K.; Billingsley, G.; Biscans, S.; Blackburn, J. K.; Blair, C. D.
2018-01-01
The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astro...
Parker, M. L.; Wilkins, D. R.; Fabian, A. C.; Grupe, D.; Dauser, T.; Matt, G.; Harrison, F. A.; Brenneman, L.; Boggs, S. E.; Christensen, F. E.;
2014-01-01
We present 3-50 keV NuSTAR observations of the active galactic nuclei Mrk 335 in a very low flux state. The spectrum is dominated by very strong features at the energies of the iron line at 5-7 keV and Compton hump from 10-30 keV. The source is variable during the observation, with the variability concentrated at low energies, which suggesting either a relativistic reflection or a variable absorption scenario. In this work, we focus on the reflection interpretation, making use of new relativistic reflection models that self consistently calculate the reflection fraction, relativistic blurring and angle-dependent reflection spectrum for different coronal heights to model the spectra. We find that the spectra can be well fitted with relativistic reflection, and that the lowest flux state spectrum is described by reflection alone, suggesting the effects of extreme light-bending occurring within approx. 2 gravitational radii (RG) of the event horizon. The reflection fraction decreases sharply with increasing flux, consistent with a point source moving up to above 10 RG as the source brightens. We constrain the spin parameter to greater than 0.9 at the 3(sigma) confidence level. By adding a spin-dependent upper limit on the reflection fraction to our models, we demonstrate that this can be a powerful way of constraining the spin parameter, particularly in reflection dominated states. We also calculate a detailed emissivity profile for the iron line, and find that it closely matches theoretical predictions for a compact source within a few RG of the black hole.
Gravitational Waves: The Evidence Mounts
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)
Energy Technology Data Exchange (ETDEWEB)
Cowell, Andrew J.; Haack, Jereme N.; McColgin, Dave W.
2006-06-08
This research is aimed at understanding the dynamics of collaborative multi-party discourse across multiple communication modalities. Before we can truly make sig-nificant strides in devising collaborative communication systems, there is a need to understand how typical users utilize com-putationally supported communications mechanisms such as email, instant mes-saging, video conferencing, chat rooms, etc., both singularly and in conjunction with traditional means of communication such as face-to-face meetings, telephone calls and postal mail. Attempting to un-derstand an individual’s communications profile with access to only a single modal-ity is challenging at best and often futile. Here, we discuss the development of RACE – Retrospective Analysis of Com-munications Events – a test-bed prototype to investigate issues relating to multi-modal multi-party discourse.
King, Michelle L.
2010-01-01
This article explores collaboration between library media educators and regular classroom teachers. The article focuses on the context of the issue, positions on the issue, the impact of collaboration, and how to implement effective collaboration into the school system. Various books and professional journals are used to support conclusions…
Bayesian reconstruction of gravitational wave bursts using chirplets
Millhouse, Margaret; Cornish, Neil J.; Littenberg, Tyson
2018-05-01
The LIGO-Virgo Collaboration uses a variety of techniques to detect and characterize gravitational waves. One approach is to use templates—models for the signals derived from Einstein's equations. Another approach is to extract the signals directly from the coherent response of the detectors in the LIGO-Virgo network. Both approaches played an important role in the first gravitational wave detections. Here we extend the BayesWave analysis algorithm, which reconstructs gravitational wave signals using a collection of continuous wavelets, to use a generalized wavelet family, known as chirplets, that have time-evolving frequency content. Since generic gravitational wave signals have frequency content that evolves in time, a collection of chirplets provides a more compact representation of the signal, resulting in more accurate waveform reconstructions, especially for low signal-to-noise events, and events that occupy a large time-frequency volume.
The present gravitational wave detection effort
International Nuclear Information System (INIS)
Riles, Keith
2010-01-01
Gravitational radiation offers a new non-electromagnetic window through which to observe the universe. The LIGO and Virgo Collaborations have completed a first joint data run with unprecedented sensitivities to gravitational waves. Results from searches in the data for a variety of astrophysical sources are presented. A second joint data run with improved detector sensitivities is underway, and soon major upgrades will be carried out to build Advanced LIGO and Advanced Virgo with expected improvements in event rates of more than 1000. In parallel there is a vigorous effort in the radio pulsar community to detect nHz gravitational waves via the timing residuals in an array of pulsars at different locations in the sky.
Cheung, Chi C. Teddy; Hogan, Jason; Graham, Peter; Kasevich, Mark; Rajendran, Surjeet; Saif, Babak; Kerr, Matthew T.; Lovellette, Michael; Wood, Kent S.; Michelson, Peter; MAGIS Team
2018-01-01
We consider the scientific potential of gravitational wave (GW) observations in the ~30 mHz to 3 Hz frequency range with the Mid-band Atomic Gravitational-wave Interferometric Sensor (MAGIS). MAGIS is a probe-class space-mission concept, using an atom-based gravitational wave detector, that will provide all-sky strain sensitivities of ~10^-21 sqrt(Hz) and better (1-year) in the GW-frequency mid-band between the LISA/L3 detector (planned 2034 launch) and ground-based Advanced LIGO/Virgo interferometers. Primary gravitational wave astrophysics science in the mid-band include GW observations of the binary black hole population discovered by Advanced LIGO/Virgo at higher-frequencies, prior to their merger stage. For such systems, MAGIS will observe the binaries in their inspiral phase, where system parameters such as eccentricities are most easily constrained, and will provide advanced, degree-scale localizations that would enable electromagnetic observations of possible precursor emission 1-week to 1-month prior to their mergers as well as prompt post-merger transient emission. Joint GW-observations with MAGIS and Advanced LIGO/Virgo covering all stages of binary coalescence will further reduce uncertainties in the GW- localizations and distances, and will be powerful paired with galaxy catalogs, to enable unique galaxy counterpart identifications in the case black hole binary mergers are completely absent of detectable electromagnetic precursor or transient signals. These possibilities for MAGIS extend to neutron star binary systems (black hole - neutron star, neutron star - neutron star), and mid-band prospects for such systems will also be considered.The MAGIS team is a collaboration between institutes in the U.S. including Stanford, AOSense, Harvard, NASA/GSFC, NASA/JPL, NIST, NRL, and UC Berkeley, and international partners at Birmingham, Bordeaux, CNRS, Dusseldorf, Ecole Normale Superieure, Florence, Hannover, and Ulm University.
High-energy Neutrino follow-up search of Gravitational Wave Event GW150914 with ANTARES and IceCube
Adrian-Martinez, S.; van Haren, H.; ANTARES Collaboration; IceCube Collaboration; Ligo Scientific Collaboration; Virgo Collaboration
2016-01-01
We present the high-energy-neutrino follow-up observations of the ?rst gravitational wave tran-sient GW150914 observed by the Advanced LIGO detectors on Sept. 14th, 2015. We search forcoincident neutrino candidates within the data recorded by the IceCube and Antares neutrino de-tectors. A possible
High-energy neutrino follow-up search of gravitational wave event GW150914 with ANTARES and IceCube
Adrian-Martinez, S.; Albert, M.A.; Andre, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J-J.; Avgitas, T.; Baret, B.; Barrios-Marti, J.; Basa, S.; Bertin, V.; Biagi, S.; Bormuth, R.; Bouwhuis, M. C.; Bruijn, J.R.; Brunner, J; Busto, J.A.A.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Chiarusi, T.; Circella, M.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.K.; Creusot, A.; Deschamps, A.; De Bonis, G.; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; Elsaesser, D.; Enzenhoefer, A.; Fehn, K.; Felis, I.; Fusco, L. A.; Galata, S.; Gay, P.; Geisselsoeder, S.; Geyer, K.; Giordano, V.; Gleixner, A.; Glotin, H.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A. J.; Hello, Y.; Hernandez-Rey, J. J.; Hoessl, J.; Hofestaedt, J.; Hugon, C.; Illuminati, G.; James, C. 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W.; Mukherjee, Arunava; Mukherjee, S.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.; Gutierrez-Neri, M.; Neunzert, A.; Newton-Howes, 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.; Oh, S. H.; Ohme, F.; Oliver, M. B.; 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.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.S; 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. J.; 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.; Prix, R.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Puerrer, M.; Qi, H.; Qin, J.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rakhmanov, M.; Rapagnani, P.; Raymond, V.; Razzano, M.; Re, V.; Read, J.; Reed, C. M.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Rew, H.; Reyes, S. D.; Ricci, F.; Riles, K.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romanov, G.; Romie, J. H.; Rosinska, D.; Rowan, S.; Ruediger, A.; Ruggi, P.; Ryan, K.A.; Sachdev, P.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.B.; Schofield, R. M. S.; Schoenbeck, A.; Schreiber, K.E.C.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, M.S.; 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.M.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, António Dias da; Simakov, D.; Singer, A; Singer, L. P.; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, R. J. E.; 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, J.R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S. E.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepanczyk, M. J.; Tacca, M.D.; Talukder, D.; Tanner, D. B.; Tapai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, W.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.; Toeyrae, D.; Travasso, F.; Traylor, G.; Trifiro, 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, Martin; van den Brand, J. F. J.; Van Den Broeck, C.F.F.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasuth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P.J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Vicere, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J. -Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, MT; 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.M.; Wessels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; Whitcomb, S. E.; White, D. J.; Whiting, B. F.; Williams, D.R.; 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.; Zadrozny, 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.
2016-01-01
We present the high-energy-neutrino follow-up observations of the first gravitational wave transient GW150914 observed by the Advanced LIGO detectors on September 14, 2015. We search for coincident neutrino candidates within the data recorded by the IceCube and Antares neutrino detectors. A possible
Energy Technology Data Exchange (ETDEWEB)
Zakharov, Aleksandr F [Russian Federation State Scientific Center ' A.I. Alikhanov Institute for Theoretical and Experimental Physics' , Moscow (Russian Federation); Sazhin, Mikhail V [P.K. Shternberg State Astronomical Institute at the M.V. Lomonosov Moscow State University, Moscow (Russian Federation)
1998-10-31
The foundations of standard microlensing theory are discussed as applied to stars in the Galactic bulge, Magellanic Clouds or other nearby galaxies and gravitational microlenses assumed to lie in-between these stars and the terrestrial observer. In contrast to the review article by Gurevich et al. [48], microlensing by compact objects is mainly considered. Criteria for the identification of microlensing events are discussed as also are microlensing events not satisfying these criteria, such as non-symmetrical light curves and chromatic and polarization effects. The Large Magellanic Cloud (LMC) and Galactic bulge microlensing data of the MACHO group are discussed in detail and also the LMC data of EROS and the Galactic bulge data of OGLE are presented. A detailed comparison of theoretical predictions and observations is given. (reviews of topical problems)
International Nuclear Information System (INIS)
Zakharov, Aleksandr F; Sazhin, Mikhail V
1998-01-01
The foundations of standard microlensing theory are discussed as applied to stars in the Galactic bulge, Magellanic Clouds or other nearby galaxies and gravitational microlenses assumed to lie in-between these stars and the terrestrial observer. In contrast to the review article by Gurevich et al. [48], microlensing by compact objects is mainly considered. Criteria for the identification of microlensing events are discussed as also are microlensing events not satisfying these criteria, such as non-symmetrical light curves and chromatic and polarization effects. The Large Magellanic Cloud (LMC) and Galactic bulge microlensing data of the MACHO group are discussed in detail and also the LMC data of EROS and the Galactic bulge data of OGLE are presented. A detailed comparison of theoretical predictions and observations is given. (reviews of topical problems)
Energy Technology Data Exchange (ETDEWEB)
Miller, Jonah Maxwell [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-10-18
This report has slides on Gravitational Waves; Pound and Rebka: A Shocking Fact; Light is a Ruler; Gravity is the Curvature of Spacetime; Gravitational Waves Made Simple; How a Gravitational Wave Affects Stuff Here; LIGO; This Detection: Neutron Stars; What the Gravitational Wave Looks Like; The Sound of Merging Neutron Stars; Neutron Star Mergers: More than GWs; The Radioactive Cloud; The Kilonova; and finally Summary, Multimessenger Astronomy.
A Case Study of On-the-fly Wide-field Radio Imaging Applied to the Gravitational Wave Event GW151226
Mooley, K. P.; Frail, D. A.; Myers, S. T.; Kulkarni, S. R.; Hotokezaka, K.; Singer, L. P.; Horesh, A.; Kasliwal, M. M.; Cenko, S. B.; Hallinan, G.
2018-04-01
We apply a newly developed on-the-fly mosaicing technique on the Jansky Very Large Array (VLA) at 3 GHz in order to carry out a sensitive search for an afterglow from the Advanced LIGO binary black hole merger event GW151226. In three epochs between 1.5 and 6 months post-merger, we observed a 100 deg2 region, with more than 80% of the survey region having an rms sensitivity of better than 150 μJy/beam, in the northern hemisphere with a merger containment probability of 10%. The data were processed in near real time and analyzed to search for transients and variables. No transients were found but we have demonstrated the ability to conduct blind searches in a time-frequency phase space where the predicted afterglow signals are strongest. If the gravitational wave event is contained within our survey region, the upper limit on any late-time radio afterglow from the merger event at an assumed mean distance of 440 Mpc is about 1029 erg s‑1 Hz‑1. Approximately 1.5% of the radio sources in the field showed variability at a level of 30%, and can be attributed to normal activity from active galactic nuclei. The low rate of false positives in the radio sky suggests that wide-field imaging searches at a few Gigahertz can be an efficient and competitive search strategy. We discuss our search method in the context of the recent afterglow detection from GW170817 and radio follow-up in future gravitational wave observing runs.
Results of the IGEC-2 search for gravitational wave bursts during 2005
Astone, P; Baggio, L; Bassan, M; Bignotto, M; Bonaldi, M; Camarda, M; Carelli, P; Cavallari, G; Cerdonio, M; Chincarini, A; Coccia, Eugenio; Conti, L; D'Antonio, S; de Rossa, M; di Paolo Emilio, M; Drago, M; Dubath, F; Fafone, V; Falferi, P; Foffa, S; Fortini, P; Frasca, S; Gemme, G; Giordano, G; Giusfredi, G; Hamilton, W O; Hanson, J; Inguscio, M; Johnson, W W; Liguori, N; Longo, S; Maggiore, M; Marin, F; Mairni, A; McHuge, H P; Mezzena, R; Miller, P; Minenkov, Y; Mion, A; Modestino, G; Moleti, A; Nettles, D; Ortolan, A; Pallottino, G V; Parodi, R; Piano Mortari, G; Poggi, S; Prodi, G A; Quintieri, L; Re, V; Rocchi, A; Ronga, F; Salemi, F; Soranzo, G; Sturani, R; Tafferello, L; Terenzi, R; Torrioli, G; Vaccaronne, R; Vandoni, G; Vedovato, G; Vinante, A; Visco, M; Vitale, S; Weaver, J; Zendri, J P; Zhang, P
2007-01-01
The network of resonant bar detectors of gravitational waves resumed coordinated observations within the International Gravitational Event Collaboration (IGEC-2). Four detectors are taking part in this collaboration: ALLEGRO, AURIGA, EXPLORER and NAUTILUS. We present here the results of the search for gravitational wave bursts over 6 months during 2005, when IGEC-2 was the only gravitational wave observatory in operation. The network data analysis implemented is based on a time coincidence search among AURIGA, EXPLORER and NAUTILUS, keeping the data from ALLEGRO for follow-up studies. With respect to the previous IGEC 1997-2000 observations, the amplitude sensitivity of the detectors to bursts improved by a factor about 3 and the sensitivity bandwidths are wider, so that the data analysis was tuned considering a larger class of detectable waveforms. Thanks to the higher duty cycles of the single detectors, we decided to focus the analysis on three-fold observation, so to ensure the identification of any singl...
Sao Sabbas, F. T.
2012-12-01
This project has the goal of establishing the Collaborative Network LEONA, to study the electrodynamical coupling of the atmospheric layers signaled by Transient Luminous Events - TLEs and high energy emissions from thunderstorms. We will develop and install a remotely controlled network of cameras to perform TLE observations in different locations in South America and one neutron detector in southern Brazil. The camera network will allow building a continuous data set of the phenomena studied in this continent. The first two trial units of the camera network are already installed, in Brazil and Peru, and two more will be installed until December 2012, in Argentina and Brazil. We expect to determine the TLE geographic distribution, occurrence rate, morphology, and possible coupling with other geophysical phenomena in South America, such as the South Atlantic Magnetic Anomaly - SAMA. We also expect to study thunderstorm neutron emissions in a region of intense electrical activity, measuring neutron fluxes with high time resolution simultaneously with TLEs and lightning for the first time in South America. Using an intensified high-speed camera for TLE observation during 2 campaigns we expect to be able to determine the duration and spatial- temporal development of the TLEs observed, to study the structure and initiation of sprites and to measure the velocity of development of sprite structures and the sprite delay. The camera was acquired via the FAPESP project DEELUMINOS (2005-2010), which also nucleated our research group Atmospheric Electrodynamical Coupling - ACATMOS. LEONA will nucleate this research in other institutions in Brazil and other countries in South America, providing continuity for this important research in our region. The camera network will be an unique tool to perform consistent long term TLE observation, and in fact is the only way to accumulate a data set for a climatological study of South America, since satellite instrumentation turns off in
The Adverse Drug Event Collaborative: a joint venture to measure medication-related patient harm.
Seddon, Mary E; Jackson, Aaron; Cameron, Chris; Young, Mary L; Escott, Linda; Maharaj, Ashika; Miller, Nigel
2012-01-25
To measure the extent of patient harm caused by medications (rate of Adverse Drug Events) in three DHBs, using a standardised trigger tool method. Counties Manukau, Capital and Coast and Canterbury DHBs decided to work collaboratively to implement the ADE Trigger Tool (TT). Definitions of ADE were agreed on and triggers refined. A random sample of closed charts (from March 2010 to February 2011) was obtained excluding patients who were admitted for <48 hours, children under the age of 18 and psychiatric admissions. In each DHB trained reviewers scanned these in a structured way to identify any of the 19 triggers. If triggers were identified, a more detailed, though time-limited review of the chart was done to determine whether an ADE had occurred. The severity of patient harm was categorised using the National Coordinating Council for Medication Error Reporting and Prevention Index. No attempt was made to determine preventability of harm and ADEs from acts of omission were excluded. The ADE TT was applied to 1210 charts and 353 ADE were identified, with an average rate of 28.9/100 admissions and 38/1,000 bed days. 94.5% of the ADE identified were in the lower severity scales with temporary harm, however in 5 patients it was considered that the ADE contributed to their death, 9 required an intervention to sustain life and 4 suffered permanent harm. The most commonly implicated drugs were morphine and other opioids, anticoagulants, antibiotics, Non Steroidal Anti-Inflammatory Drugs (NSAIDs) and diuretics. Patients who suffered an ADE were more likely to be female, older with more complex medical illnesses, and have a longer length of stay. The rate of medication-related harm identified by the ADE TT is considerably higher than that identified through traditional voluntary reporting mechanisms. The ADE TT provides a standardised measure of harm over time that can be used to determine trends and the effect of medication safety improvement programmes. This study not
Mixed Methods Analysis of Medical Error Event Reports: A Report from the ASIPS Collaborative
National Research Council Canada - National Science Library
Harris, Daniel M; Westfall, John M; Fernald, Douglas H; Duclos, Christine W; West, David R; Niebauer, Linda; Marr, Linda; Quintela, Javan; Main, Deborah S
2005-01-01
The Applied Strategies for Improving Patient Safety (ASIPS) collaborative developed an ambulatory primary care patient safety reporting system through an Agency for Healthcare Research and Quality (AHRQ...
A radiometer for stochastic gravitational waves
International Nuclear Information System (INIS)
Ballmer, Stefan W
2006-01-01
The LIGO Scientific Collaboration recently reported a new upper limit on an isotropic stochastic background of gravitational waves obtained based on the data from the third LIGO science run (S3). Here I present a new method for obtaining directional upper limits on stochastic gravitational waves that essentially implements a gravitational wave radiometer. The LIGO Scientific Collaboration intends to use this method for future LIGO science runs
Directory of Open Access Journals (Sweden)
Ozgur Sanli H
2010-01-01
Full Text Available Wireless sensor networks are often required to provide event miss-ratio assurance for a given event type. To meet such assurances along with minimum energy consumption, this paper shows how a node's activation and rate assignment is dependent on its distance to event sources, and proposes a practical coverage and rate allocation (CORA protocol to exploit this dependency in realistic environments. Both uniform event distribution and nonuniform event distribution are considered and the notion of ideal correlation distance around a clusterhead is introduced for on-duty node selection. In correlation distance guided CORA, rate assignment assists coverage scheduling by determining which nodes should be activated for minimizing data redundancy in transmission. Coverage scheduling assists rate assignment by controlling the amount of overlap among sensing regions of neighboring nodes, thereby providing sufficient data correlation for rate assignment. Extensive simulation results show that CORA meets the required event miss-ratios in realistic environments. CORA's joint coverage scheduling and rate allocation reduce the total energy expenditure by 85%, average battery energy consumption by 25%, and the overhead of source coding up to 90% as compared to existing rate allocation techniques.
International Nuclear Information System (INIS)
Choi, J.-Y.; Shin, I.-G.; Park, S.-Y.; Han, C.; Gould, A.; Gaudi, B. S.; Henderson, C. B.; Sumi, T.; Udalski, A.; Beaulieu, J.-P.; Street, R.; Dominik, M.; Allen, W.; Almeida, L. A.; Bos, M.; Christie, G. W.; Depoy, D. L.; Dong, S.; Drummond, J.; Gal-Yam, A.
2012-01-01
We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of θ E ∼ 0.08 mas combined with the short timescale of t E ∼ 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of ∼0.84 M ☉ is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio.
Energy Technology Data Exchange (ETDEWEB)
Choi, J.-Y.; Shin, I.-G.; Park, S.-Y.; Han, C. [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of); Gould, A.; Gaudi, B. S.; Henderson, C. B. [Department of Astronomy, Ohio State University, 140 W. 18th Ave., Columbus, OH 43210 (United States); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Udalski, A. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Beaulieu, J.-P. [Institut d' Astrophysique de Paris, UMR7095 CNRS-Universite Pierre and Marie Curie, 98 bis boulevard Arago, 75014 Paris (France); Street, R. [Las Cumbres Observatory Global Telescope Network, 6740B Cortona Dr, Suite 102, Goleta, CA 93117 (United States); Dominik, M. [School of Physics and Astronomy, SUPA, University of St. Andrews, North Haugh, St. Andrews, KY16 9SS (United Kingdom); Allen, W. [Vintage Lane Observatory, Blenheim (New Zealand); Almeida, L. A. [Instituto Nacional de Pesquisas Espaciais/MCTI, Sao Jose dos Campos, Sao Paulo (Brazil); Bos, M. [Molehill Astronomical Observatory, North Shore (New Zealand); Christie, G. W. [Auckland Observatory, P.O. Box 24-180, Auckland (New Zealand); Depoy, D. L. [Department of Physics, Texas A and M University, College Station, TX (United States); Dong, S. [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Drummond, J. [Possum Observatory, Patutahi (New Zealand); Gal-Yam, A. [Benoziyo Center for Astrophysics, Weizmann Institute (Israel); Collaboration: muFUN Collaboration; MOA Collaboration; OGLE Collaboration; PLANET Collaboration; RoboNet Collaboration; MiNDSTEp Consortium; and others
2012-05-20
We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of {theta}{sub E} {approx} 0.08 mas combined with the short timescale of t{sub E} {approx} 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of {approx}0.84 M{sub Sun} is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio.
DEFF Research Database (Denmark)
Shin, I.-G; Han, C.; Choi, J.-Y
2012-01-01
solution by follow-up radial-velocity observation. For both events, the caustic-crossing parts of the light curves, which are critical for determining the physical lens parameters, were resolved by high-cadence survey observations and thus it is expected that the number of microlensing binaries...
CERN. Geneva
2005-01-01
We will present a brief introduction to the physics of gravitational waves and their properties. We will review potential astrophysical sources of gravitational waves, and the physics and astrophysics that can be learned from their study. We will survey the techniques and technologies for detecting gravitational waves for the first time, including bar detectors and broadband interferometers, and give a brief status report on the international search effort, with special emphasis on the LIGO detectors and search results.
Model petri net of adaptive traffic lights and its collaboration with a special event
Directory of Open Access Journals (Sweden)
Tristono Tomi
2018-01-01
Full Text Available Traffic lights have an important role as the system control of vehicles flow on the urban network. Commonly, most countries still using fixed time strategy. Our research proposes the adaptive traffic lights model to response the traffic demand. It uses basic Petri net as a general modeling framework. Foractuating method of minimum and maximum green signal time interval, the green traffic lights have three-time extension units. Next, we collaborate on a case of the existence of railways that crosses on the southern arm of an intersection. We introduce both of collaboration model design of traffic lights and the railway's gate which always closes while a train passing. Verification and validation of the model are based on the simulation result of vehicles queue. The collaboration model design of traffic lights has excellent performance, and it can resolve the congestion problem better than conventional schedule.
Sanger, Denise; Hernandez, Debra; Libes, Susan; Voulgaris, George; Davis, Braxton; Smith, Erik; Shuford, Rebecca; Porter, Dwayne; Koepfler, Eric; Bennett, Joseph
2010-09-01
Communication of knowledge between the scientific and management communities is a difficult process complicated by the distinctive nature of professional career goals of scientists and decision-makers. This article provides a case history highlighting a collaboration between the science and management communities that resulted from a response to a 2004 hypoxia, or low dissolved oxygen, event in Long Bay, off Myrtle Beach, South Carolina. A working group of scientists and decision-makers was established at the time of the event and has continued to interact to develop a firm understanding of the drivers responsible for hypoxia formation in Long Bay. Several factors were found to be important to ensure that these collaborative efforts were productive: (1) genuine interest in collaboratively working across disciplines to examine a problem; (2) commitment by agency leadership, decision-makers, and researchers to create successful communication mechanisms; (3) respect for each others’ perspectives and an understanding how science and management are performed and that they are not mutually exclusive; (4) networking among researchers and decision-makers to ensure appropriate team members are involved in the process; (5) use of decision-maker input in the formulation of research and monitoring projects; and (6) commitment of resources for facilitation to ensure that researchers and decision-makers are communicating effectively.
Gravitation, Symmetry and Undergraduates
Jorgensen, Jamie
2001-04-01
This talk will discuss "Project Petrov" Which is designed to investigate gravitational fields with symmetry. Project Petrov represents a collaboration involving physicists, mathematicians as well as graduate and undergraduate math and physics students. An overview of Project Petrov will be given, with an emphasis on students' contributions, including software to classify and generate Lie algebras, to classify isometry groups, and to compute the isometry group of a given metric.
A first comparison of SLOPE and other LIGO burst event trigger generators
International Nuclear Information System (INIS)
Stuver, Amber L; Finn, Lee Samuel
2006-01-01
A number of different methods have been proposed to identify unanticipated burst sources of gravitational waves in data arising from LIGO and other gravitational wave detectors. When confronted with such a wide variety of methods one is moved to ask if they are all necessary, i.e. given detector data that is assumed to have no gravitational wave signals present, do they generally identify the same events with the same efficiency, or do they each 'see' different things in the detector? Here we consider three different methods, which have been used within the LIGO Scientific Collaboration as part of its search for unanticipated gravitational wave bursts. We find that each of these three different methods developed for identifying candidate gravitational wave burst sources are, in fact, attuned to significantly different features in detector data, suggesting that they may provide largely independent lists of candidate gravitational wave burst events
Ishitsuka, J.; Asai, A.; Morita, S.; Terrazas, R.; Cabezas, D.; Gutierrez, V.; Martinez, L.; Buleje, Y.; Loayza, R.; Nakamura, N.; Takasao, S.; Yoshinaga, Y.; Hillier, A.; Otsuji, K.; Shibata, K.; Ishitsuka, M.; Ueno, S.; Kitai, R.; Ishii, T.; Ichimoto, K.; Nagata, S.; Narukage, N.
2014-02-01
In 2008 we inaugurated the new Solar Observatory in collaboration with Faculty of Sciences of San Luis Gonzaga de Ica National University, 300 km south of Lima. In March of 2010 a Flare Monitoring Telescope of Hida Observatory of Kyoto University arrived to Ica, part of CHAIN Project (Continuous H-alpha Imaging Network). In October of the same year we hosted the First FMT Workshop in Ica, then in July of 2011 the Second FMT Workshop was opened. Since that we are focused on two events registered by FMT in Peru to publish results. FMT is a good tool to introduce young people from universities into scientific knowledge; it is good also for education in Solar Physics and outreach. Details of this successful collaboration will be explained in this presentation.
High Tempo Knowledge Collaboration in Wikipedia's Coverage of Breaking News Events
Keegan, Brian C.
2012-01-01
When major news breaks in our hyper-connected society, we increasingly turn to an encyclopedia for the latest information. Wikipedia's coverage of breaking news events attracts unique levels of attention; the articles with the most page views, edits, and contributors in any given month since 2003 are related to current events. Extant…
International Nuclear Information System (INIS)
Miyake, N.; Abe, F.; Furusawa, K.; Itow, Y.; Udalski, A.; Kubiak, M.; Szymański, M. K.; Pietrzyński, G.; Soszyński, I.; Ulaczyk, K.; Wyrzykowski, L.; Sumi, T.; Bennett, D. P.; Dong, S.; Gould, A.; Street, R. A.; Greenhill, J.; Bond, I. A.; Fukui, A.; Holderness, S.
2012-01-01
We report the extremely high-magnification (A > 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories. The binary lens model that includes the effects of parallax (known orbital motion of the Earth) and orbital motion of the lens yields a binary lens mass ratio of q = 0.321 ± 0.007 and a projected separation of s = 0.072 ± 0.001 in units of the Einstein radius. The parallax parameters allow us to determine the lens distance D L = 3.11 ± 0.39 kpc and total mass M L = 1.40 ± 0.18 M ☉ ; this leads to the primary and secondary components having masses of M 1 = 1.06 ± 0.13 M ☉ and M 2 = 0.34 ± 0.04 M ☉ , respectively. The parallax model indicates that the binary lens system is likely constructed by the main-sequence stars. On the other hand, we used a Bayesian analysis to estimate probability distributions by the model that includes the effects of xallarap (possible orbital motion of the source around a companion) and parallax (q = 0.270 ± 0.005, s = 0.083 ± 0.001). The primary component of the binary lens is relatively massive, with M 1 = 0.9 +4.6 –0.3 M ☉ and it is at a distance of D L = 2.6 +3.8 –0.9 kpc. Given the secure mass ratio measurement, the companion mass is therefore M 2 = 0.2 +1.2 –0.1 M ☉ . The xallarap model implies that the primary lens is likely a stellar remnant, such as a white dwarf, a neutron star, or a black hole.
Energy Technology Data Exchange (ETDEWEB)
Miyake, N.; Abe, F.; Furusawa, K.; Itow, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Udalski, A.; Kubiak, M.; Szymanski, M. K.; Pietrzynski, G.; Soszynski, I.; Ulaczyk, K.; Wyrzykowski, L. [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Sumi, T. [Department of Earth and Space Science, Osaka University, Osaka 560-0043 (Japan); Bennett, D. P. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Dong, S.; Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Street, R. A. [Las Cumbres Observatory, 6740B Cortona Drive, Suite 102, Goleta, CA 93117 (United States); Greenhill, J. [School of Maths and Physics, University of Tasmania, Private bag 37, GPO Hobart, Tasmania 7001 (Australia); Bond, I. A. [Institute for Information and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland 1330 (New Zealand); Fukui, A. [Okayama Astrophysical Observatory, National Astronomical Observatory of Japan, Okayama 719-0232 (Japan); Holderness, S., E-mail: nmiyake@stelab.nagoya-u.ac.jp [Computer Science Department, University of Auckland, Auckland (New Zealand); Collaboration: OGLE Collaboration; MOA Collaboration; muFUN Collaboration; RoboNet Collaboration; PLANET Collaboration; and others
2012-06-20
We report the extremely high-magnification (A > 1000) binary microlensing event OGLE-2007-BLG-514. We obtained good coverage around the double peak structure in the light curve via follow-up observations from different observatories. The binary lens model that includes the effects of parallax (known orbital motion of the Earth) and orbital motion of the lens yields a binary lens mass ratio of q = 0.321 {+-} 0.007 and a projected separation of s = 0.072 {+-} 0.001 in units of the Einstein radius. The parallax parameters allow us to determine the lens distance D{sub L} = 3.11 {+-} 0.39 kpc and total mass M{sub L} = 1.40 {+-} 0.18 M{sub Sun }; this leads to the primary and secondary components having masses of M{sub 1} = 1.06 {+-} 0.13 M{sub Sun} and M{sub 2} = 0.34 {+-} 0.04 M{sub Sun }, respectively. The parallax model indicates that the binary lens system is likely constructed by the main-sequence stars. On the other hand, we used a Bayesian analysis to estimate probability distributions by the model that includes the effects of xallarap (possible orbital motion of the source around a companion) and parallax (q = 0.270 {+-} 0.005, s = 0.083 {+-} 0.001). The primary component of the binary lens is relatively massive, with M{sub 1} = 0.9{sup +4.6}{sub -0.3} M{sub Sun} and it is at a distance of D{sub L} = 2.6{sup +3.8}{sub -0.9} kpc. Given the secure mass ratio measurement, the companion mass is therefore M{sub 2} = 0.2{sup +1.2}{sub -0.1} M{sub Sun }. The xallarap model implies that the primary lens is likely a stellar remnant, such as a white dwarf, a neutron star, or a black hole.
Study of the Dijet Invariant Mass in W+2jet candidate events by the D0 Collaboration
CERN. Geneva
2011-01-01
We present a study of the dijet invariant mass spectrum in events with two jets produced in association with a W boson in data corresponding to an integrated luminosity of 4.3 fb-1 collected with the D0 detector at sqrt{s}=1.96 TeV. As we do not find an evidence for anomalous resonant dijet production in the mass range 110-170 GeV, we derive upper limits on the production cross section of a dijet resonance reported by the CDF Collaboration.
Mixed Methods Analysis of Medical Error Event Reports: A Report from the ASIPS Collaborative
National Research Council Canada - National Science Library
Harris, Daniel M; Westfall, John M; Fernald, Douglas H; Duclos, Christine W; West, David R; Niebauer, Linda; Marr, Linda; Quintela, Javan; Main, Deborah S
2005-01-01
.... This paper presents a mixed methods approach to analyzing narrative error event reports. Mixed methods studies integrate one or more qualitative and quantitative techniques for data collection and analysis...
International Nuclear Information System (INIS)
Bondi, H.
1979-01-01
In spite of the strength of gravitational focres between celestial bodies, gravitational capture is not a simple concept. The principles of conservation of linear momentum and of conservation of angular momentum, always impose severe constraints, while conservation of energy and the vital distinction between dissipative and non-dissipative systems allows one to rule out capture in a wide variety of cases. In complex systems especially those without dissipation, long dwell time is a more significant concept than permanent capture. (author)
The Prospect of Neutrinos with Gravitational Waves
Kohler, Susanna
2017-10-01
With the first detection of gravitational waves in 2015, scientists celebrated the opening of a new window to the universe. But multi-messenger astronomy astronomy based on detections of not just photons, but other signals as well was not a new idea at the time: we had already detected tiny, lightweight neutrinos emitted from astrophysical sources. Will we be able to combine observations of neutrinos and gravitational waves in the future to provide a deeper picture of astrophysical events?Signs of a MergerArtists impression of the first stage of a binary neutron star merger. [NASA, ESA, and A. Feild (STScI)]If the answer is yes, the key will probably be short gamma-ray bursts (SGRBs). Theory predicts that when a neutron star merges with another compact object (either another neutron star or a black hole), a number of signals may be observable. These include:gravitational waves as the binary spirals inward,a brief burst of gamma rays at merger (this is the SGRB),high-energy neutrino emission during the SGRB,optical and infrared emission after the merger in the form of a kilonova, andradio afterglows of the merger remnants.While weve observed the various electromagnetic components of this picture, the multi-messenger part is lacking: gravitational-wave detections havent been made in conjunction with electromagnetic counterparts thus far, and the only confirmed astrophysical sources of neutrinos are the Sun and Supernova 1987A.Pedicted neutrino fluxes during different stages of emission in an SGRB. [Kimura et al. 2017]Can we expect this to change in the future? A team of authors led by Shigeo Kimura (Pennsylvania State University) has now explored the likelihood that well be able to detect high-energy neutrinos in association with future gravitational-wave events.Detecting the SGRB NeutrinosKimura and collaborators first estimate the flux of high-energy neutrinos expected during various emission phases of an SGRB. They show that a period of late-time emission, known
Gravitational waves from gravitational collapse
Energy Technology Data Exchange (ETDEWEB)
Fryer, Christopher L [Los Alamos National Laboratory; New, Kimberly C [Los Alamos National Laboratory
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 Waves from Gravitational Collapse
Directory of Open Access Journals (Sweden)
Chris L. Fryer
2011-01-01
Full Text Available Gravitational-wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion-induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.
Gravitational Waves from Gravitational Collapse.
Fryer, Chris L; New, Kimberly C B
2011-01-01
Gravitational-wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion-induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars. Supplementary material is available for this article at 10.12942/lrr-2011-1.
Reyes, Christina Delos; Pagano, Maria Elizabeth; Ronis, Robert J
2009-04-01
Alcohol relapse is impacted by a variety of environmental, interpersonal, and intrapersonal factors. We examined the interaction between stressful life events, personality disorder subtype, and alcohol relapse among individuals enrolled in the Collaborative Longitudinal Personality Disorders Study (CLPS). Negative life events predicted relapse in all subjects. In individuals with a history of an alcohol use disorder prior to study entry, positive life events also predicted alcohol relapse. Individuals with Antisocial Personality Disorder (ASPD) were found to be twice as likely to relapse in response to life stressors compared to individuals with Obsessive-Compulsive Personality Disorder (OCPD), who were half as likely to relapse in response to life stressors. Further analysis revealed that individuals with OCPD and no history of an alcohol use disorder were almost 10 times more likely to relapse in the face of a stressful romantic problem, while those with ASPD and a history of an alcohol use disorder were six times more likely to relapse in response to a stressful financial event. These findings have implications for both the assessment and the treatment of individuals who present with co-morbid personality and alcohol use disorders.
The gravitational Schwinger effect and attenuation of gravitational waves
McDougall, Patrick Guarneri
This paper will discuss the possible production of photons from gravitational waves. This process is shown to be possible by examining Feynman diagrams, the Schwinger Effect, and Hawking Radiation. The end goal of this project is to find the decay length of a gravitational wave and assert that this decay is due to photons being created at the expense of the gravitational wave. To do this, we first find the state function using the Klein Gordon equation, then find the current due to this state function. We then take the current to be directly proportional to the production rate per volume. This is then used to find the decay length that this kind of production would produce, gives a prediction of how this effect will change the distance an event creating a gravitational wave will be located, and shows that this effect is small but can be significant near the source of a gravitational wave.
SYSTEMS FOR SUPPORT OF COLLABORATIVE STUDIES IN THE COLLA ENVIRONMENT BASED ON THE EVENT BUSH METHOD
Directory of Open Access Journals (Sweden)
P. Diviacco
2014-09-01
Full Text Available Problem statement. Conventional tools of online communication in global networks for support of scientific and research projects fail to handle specific issues that arise at scientific collaboration of different scientific schools. They cannot be used to bring together the knowledge relating to the same field but generated in various scientific schools, under different paradigms and on different conceptual grounds. Existing software solutions, both synchronous (e.g., Webex or ShowDocument and asynchronous (Zimbra, Google Docs and others are efficient only when the users share similar understanding of the context and do not bring their own non-formalized meanings in it. Meanwhile, a tool is needed for scientific cooperation that makes it possible to bring one’s own meanings and relate them to the common context.
The origin of SEP events: New research collaboration and network on space weather
Miteva, Rositsa; Kashapova, Larisa; Myagkova, Irina; Meshalkina, Nataliia; Petrov, Nikola; Bogomolov, Andrey; Myshyakov, Ivan; Tsvetkov, Tsvetan; Danov, Dimitar; Zdanov, Dmitriy
2017-11-01
A new project on the solar energetic particles (SEPs) and their solar origins (flares and coronal mass ejections) is described here. The main aim of this project is to answer the question - whether the SEPs observed in situ are driven by flares, by CMEs or both accelerators contribute to an extent which varies from event to event - by deducing a quantitative measure of the flare vs. CME contribution, duration and efficiency. New observations (SONG/Koronas-F, Relec/Vernov) and new approaches of analysis will be utilized (e.g., magnetic topology of active regions using 3D extrapolation techniques of detailed case studies together with statistical analysis of the phenomena). In addition, the identification of the uncertainty limits of SEP injection, onset time and testing the validity of assumptions often taken for granted (association procedures, solar activity longitudinal effects, correlation analysis, etc.) are planned. The project outcomes have the capacity to contribute to other research fields for improvement of modeling schemes and forecasting methods of space weather events.
Dodelson, Scott
2017-01-01
Gravitational lensing is a consequence of general relativity, where the gravitational force due to a massive object bends the paths of light originating from distant objects lying behind it. Using very little general relativity and no higher level mathematics, this text presents the basics of gravitational lensing, focusing on the equations needed to understand the phenomena. It then applies them to a diverse set of topics, including multiply imaged objects, time delays, extrasolar planets, microlensing, cluster masses, galaxy shape measurements, cosmic shear, and lensing of the cosmic microwave background. This approach allows undergraduate students and others to get quickly up to speed on the basics and the important issues. The text will be especially relevant as large surveys such as LSST and Euclid begin to dominate the astronomical landscape. Designed for a one semester course, it is accessible to anyone with two years of undergraduate physics background.
A giant planet beyond the snow line in microlensing event OGLE-2011-BLG-0251
DEFF Research Database (Denmark)
Kains, N.; Street, R.A.; Choi, J.-Y.
2013-01-01
Aims. We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting microlensing observations towards the Galactic bulge. Methods. Based on detailed modelling of the observed light cu...
Schäfer, G.; Schutz, B.
1996-01-01
Gravity is truly universal. It is the force that pulls us to the Earth, that keeps the planets and moons in their orbits, and that causes the tides on the Earth to ebb and flow. It even keeps the Sun shining. Yet on a laboratory scale gravity is extremely weak. The Coulomb force between two protons is 1039 times stronger than the gravitational force between them. Moreover, Newton's gravitational constant is the least accurately known of the fundamental constants: it has been measured to 1 par...
International Nuclear Information System (INIS)
Bassi, Angelo; Großardt, André; Ulbricht, Hendrik
2017-01-01
We discuss effects of loss of coherence in low energy quantum systems caused by or related to gravitation, referred to as gravitational decoherence. These effects, resulting from random metric fluctuations, for instance, promise to be accessible by relatively inexpensive table-top experiments, way before the scales where true quantum gravity effects become important. Therefore, they can provide a first experimental view on gravity in the quantum regime. We will survey models of decoherence induced both by classical and quantum gravitational fluctuations; it will be manifest that a clear understanding of gravitational decoherence is still lacking. Next we will review models where quantum theory is modified, under the assumption that gravity causes the collapse of the wave functions, when systems are large enough. These models challenge the quantum-gravity interplay, and can be tested experimentally. In the last part we have a look at the state of the art of experimental research. We will review efforts aiming at more and more accurate measurements of gravity ( G and g ) and ideas for measuring conventional and unconventional gravity effects on nonrelativistic quantum systems. (topical review)
Rahvar, Sohrab
2018-05-01
In this work, we study the interaction of the electromagnetic wave (EW) from a distant quasar with the gravitational wave (GW) sourced by the binary stars. While in the regime of geometric optics, the light bending due to this interaction is negligible, we show that the phase shifting on the wavefront of an EW can produce the diffraction pattern on the observer plane. The diffraction of the light (with the wavelength of λe) by the gravitational wave playing the role of gravitational grating (with the wavelength of λg) has the diffraction angle of Δβ ˜ λe/λg. The relative motion of the observer, the source of gravitational wave and the quasar results in a relative motion of the observer through the interference pattern on the observer plane. The consequence of this fringe crossing is the modulation in the light curve of a quasar with the period of few hours in the microwave wavelength. The optical depth for the observation of this phenomenon for a Quasar with the multiple images strongly lensed by a galaxy where the light trajectory of some of the images crosses the lensing galaxy is τ ≃ 0.2. By shifting the time-delay of the light curves of the multiple images in a strong lensed quasar and removing the intrinsic variations of a quasar, our desired signals, as a new method for detection of GWs can be detected.
Nelson, F. E.; Bryant, T.; Wellington, P.; Dooley, J.; Bird, M.
2008-12-01
Delaware is a small state with, by virtue of its coastal location, a large stake in climatic change in the polar regions. The University of Delaware has maintained a strong presence in cold-regions research since the mid-1940s, when William Samuel Carlson, a highly accomplished Arctic explorer, military strategist, and earth scientist, was named 20th President (1946-50) of the University. Carlson played a leading role in two of the University of Michigan's Greenland expeditions in the late 1920s and early 1930s. As Director of the Arctic, Desert, and Tropic Branch of the US Army Air Forces Tactical Center during World War II, Colonel Carlson played a role in developing several air transportation routes through the Arctic that helped to facilitate the Allied victory in Europe. Carlson authored many scientific and popular publications concerned with the Arctic, including the books Greenland Lies North (1940) and Lifelines Through the Arctic (1962). Although the University of Delaware has maintained a vigorous and continuous program of polar research since Carlson's tenure, the faculty, staff, and students involved are diffused throughout the University's colleges and departments, without an institutional focal point. Consequently, although many of these individuals are well known in their respective fields, the institution has not until recently been perceived widely as a center of polar-oriented research. The goals of the Carlson International Polar Year Events are to: (a) develop a sense of community among UD's diffuse polar-oriented researchers and educators; (b) create a distinctive and highly visible role for UD in the milieu of IPY activities; (c) promote interest in and knowledge about the polar regions in the State of Delaware, at all educational levels; (d) forge a close relationship between UD and the American Geographical Society, a national organization involved closely with previous International Polar Years; and (e) create a new basis for development
Neutrinos from gravitational collapse
International Nuclear Information System (INIS)
Mayle, R.; Wilson, J.R.; Schramm, D.N.
1986-05-01
Detailed calculations are made of the neutrino spectra emitted during gravitational collapse events (Type II supernovae). Those aspects of the neutrino signal which are relatively independent of the collapse model and those aspects which are sensitive to model details are discussed. The easier-to-detect high energy tail of the emitted neutrinos has been calculated using the Boltzmann equation which is compared with the result of the traditional multi-group flux limited diffusion calculations. 8 figs., 28 refs
Tasting the Tree of Life: Development of a Collaborative, Cross-Campus, Science Outreach Meal Event.
Clement, Wendy L; Elliott, Kathryn T; Cordova-Hoyos, Okxana; Distefano, Isabel; Kearns, Kate; Kumar, Raagni; Leto, Ashley; Tumaliuan, Janis; Franchetti, Lauren; Kulesza, Evelyn; Tineo, Nicole; Mendes, Patrice; Roth, Karen; Osborn, Jeffrey M
2018-01-01
Communicating about science with the public can present a number of challenges, from participation to engagement to impact. In an effort to broadly communicate messages regarding biodiversity, evolution, and tree-thinking with the campus community at The College of New Jersey (TCNJ), a public, primarily undergraduate institution, we created a campus-wide, science-themed meal, "Tasting the Tree of Life: Exploring Biodiversity through Cuisine." We created nine meals that incorporated 149 species/ingredients across the Tree of Life. Each meal illustrated a scientific message communicated through interactions with undergraduate biology students, informational signs, and an interactive website. To promote tree-thinking, we reconstructed a phylogeny of all 149 ingredients. In total, 3,262 people attended the meal, and evaluations indicated that participants left with greater appreciation for the biodiversity and evolutionary relatedness of their food. A keynote lecture and a coordinated social media campaign enhanced the scientific messages, and media coverage extended the reach of this event. "Tasting the Tree of Life" highlights the potential of cuisine as a valuable science communication tool.
Cavaglia, Marco; Hendry, M.; Ingram, D.; Milde, S.; Pandian, S. R.; Reitze, D.; Riles, K.; Schutz, B.; Stuver, A. L.; Summerscales, T.; Ugolini, D.; Thacker, J.; Vallisneri, M.; Zermeno, A.
2008-05-01
The nascent field of gravitational wave astronomy offers many opportunities for effective and inspirational astronomy outreach. Gravitational waves, the `ripples in spacetime' predicted by Einstein's general theory of relativity, are produced by some of the most energetic and dramatic phenomena in the cosmos, including black holes, neutron stars and supernovae - and their discovery should help to address a number of fundamental questions in physics, from the evolution of stars and galaxies to the origin of dark energy and the nature of spacetime itself. Moreover, the cutting-edge technology developed to search for gravitational waves is pushing back the frontiers of many fields, from lasers and materials science to high performance computing, and thus provides a powerful showcase for the attractions and challenges of a career in science and engineering. For several years a worldwide network of ground-based laser interferometric gravitational wave detectors, built and run by the LIGO Scientific Collaboration, has been fully operational. These detectors are already among the most sensitive scientific instruments on the planet but in the next few years their sensitivity will achieve further significant improvement. Those developments promise to open an exciting new window on the Universe, heralding the arrival of gravitational wave astronomy as a revolutionary, new observational field. In this poster we describe the extensive program of public outreach activities already undertaken by the LIGO Scientific Collaboration, and a number of special events which we are planning for IYA2009. These activities include: * programs at Science Centers and Observatory Visitor Centers * programs on gravitational wave astronomy for the classroom, across the K-12 spectrum * interdisciplinary events linking gravitational wave astronomy to music and the visual arts * research experiences for schools and citizens through the highly successful `Einstein@Home' program.
Albert, A.; André, M.; Anghinolfi, M.; Anton, G.; Ardid, M.; Aubert, J.-J.; Avgitas, T.; Baret, B.; Barrios-Martí, J.; Basa, S.; Belhorma, B.; Bertin, V.; Biagi, S.; Bormuth, R.; Bourret, S.; Bouwhuis, M.C.; Brânzas, H.; Bruijn, R.; Brunner, J.; Busto, J.; Capone, A.; Caramete, L.; Carr, J.; Celli, S.; Cherkaoui El Moursli, R.; Chiarusi, T.; Circella, M.; Coelho, J.A.B.; Coleiro, A.; Coniglione, R.; Costantini, H.; Coyle, P.; Creusot, A.; Díaz, A.F.; Deschamps, A.; De Bonis, G.; Distefano, C.; Di Palma, I.; Domi, A.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; El Bojaddaini, I.; El Khayati, N.; Elsässer, D.; Enzenhöfer, A.; Ettahiri, A.; Fassi, F.; Felis, I.; Fusco, L.A.; Gay, P.; Giordano, V.; Glotin, H.; Grégoire, T.; Gracia-Ruiz, R.; Graf, K.; Hallmann, S.; van Haren, H.; Heijboer, A.J.; Hello, Y.; Hernandez-Rey, J.J.; Hößl, J.; Hofestädt, J.; Hugon, C.; Illuminati, G.; James, C.W.; de Jong, M.; Jongen, M.; Kadler, M.; Kalekin, O.; Katz, U.; Kießling, D.; Kouchner, A.; Kreter, M.; Kreykenbohm, I.; Kulikovskiy, V.; Lachaud, C.; Lahmann, R.; Lefèvre, D.; Leonora, E.; Lotze, M.; Loucatos, S.; Marcelin, M.; Margiotta, A.; Marinelli, A.; Martínez-Mora, J.A.; Mele, R.; Melis, K.; Michael, T.; Migliozzi, P.; Moussa, A.; Navas, S.; Nezri, E.; Organokov, M.; Pavalas, G.E.; Pellegrino, C.; Perrina, C.; Piattelli, P.; Popa, V.; Pradier, T.; Quinn, L.; Racca, C.; Riccobene, G.; Sánchez-Losa, A.; Saldaña, M.; Salvadori, I.; Samtleben, D.F.E.; Sanguineti, M.; Sapienza, P.; Schüssler, F.; Sieger, C.; Spurio, M.; Stolarczyk, Th.; Taiuti, M.; Tayalati, Y.; Trovato, A.; Turpin, D.; Tönnis, C.; Vallage, B.; Van Elewyck, V.; Versari, F.; Vivolo, D.; Vizzoca, A.; Wilms, J.; Zornoza, J.D.; Zúñiga, J.
2017-01-01
Advanced LIGO detected a significant gravitational wave signal (GW170104) originating from the coalescence of two black holes during the second observation run on January 4th, 2017. An all-sky high-energy neutrino follow-up search has been made using data from the Antares neutrino telescope,
Ciufolini, I; Moschella, U; Fre, P
2001-01-01
Gravitational waves (GWs) are a hot topic and promise to play a central role in astrophysics, cosmology, and theoretical physics. Technological developments have led us to the brink of their direct observation, which could become a reality in the coming years. The direct observation of GWs will open an entirely new field: GW astronomy. This is expected to bring a revolution in our knowledge of the universe by allowing the observation of previously unseen phenomena, such as the coalescence of compact objects (neutron stars and black holes), the fall of stars into supermassive black holes, stellar core collapses, big-bang relics, and the new and unexpected.With a wide range of contributions by leading scientists in the field, Gravitational Waves covers topics such as the basics of GWs, various advanced topics, GW detectors, astrophysics of GW sources, numerical applications, and several recent theoretical developments. The material is written at a level suitable for postgraduate students entering the field.
Hakim, Rémi
1994-01-01
Il existe à l'heure actuelle un certain nombre de théories relativistes de la gravitation compatibles avec l'expérience et l'observation. Toutefois, la relativité générale d'Einstein fut historiquement la première à fournir des résultats théoriques corrects en accord précis avec les faits.
Results of the IGEC-2 search for gravitational wave bursts during 2005
International Nuclear Information System (INIS)
Astone, P.; Babusci, D.; Giordano, G.; Marini, A.; Modestino, G.; Quintieri, L.; Ronga, F.; Baggio, L.; Bassan, M.; Fafone, V.; Moleti, A.; Bignotto, M.; Cerdonio, M.; Conti, L.; Drago, M.; Liguori, N.; Bonaldi, M.; Falferi, P.; Vinante, A.; Camarda, M.
2007-01-01
The network of resonant bar detectors of gravitational waves resumed coordinated observations within the International Gravitational Event Collaboration (IGEC-2). Four detectors are taking part in this Collaboration: ALLEGRO, AURIGA, EXPLORER and NAUTILUS. We present here the results of the search for gravitational wave bursts over 6 months during 2005, when IGEC-2 was the only gravitational wave observatory in operation. The implemented network data analysis is based on a time coincidence search among AURIGA, EXPLORER and NAUTILUS; ALLEGRO data was reserved for follow-up studies. The network amplitude sensitivity to bursts improved by a factor ≅3 over the 1997-2000 IGEC observations; the wider sensitive band also allowed the analysis to be tuned over a larger class of waveforms. Given the higher single-detector duty factors, the analysis was based on threefold coincidence, to ensure the identification of any single candidate of gravitational waves with high statistical confidence. The false detection rate was as low as 1 per century. No candidates were found
Gravitational Physics Research
Wu, S. T.
2000-01-01
Gravitational physics research at ISPAE is connected with NASA's Relativity Mission (Gravity Probe B (GP-B)) which will perform a test of Einstein's General Relativity Theory. GP-B will measure the geodetic and motional effect predicted by General Relativity Theory with extremely stable and sensitive gyroscopes in an earth orbiting satellite. Both effects cause a very small precession of the gyroscope spin axis. The goal of the GP-B experiment is the measurement of the gyroscope precession with very high precision. GP-B is being developed by a team at Stanford University and is scheduled for launch in the year 2001. The related UAH research is a collaboration with Stanford University and MSFC. This research is focussed primarily on the error analysis and data reduction methods of the experiment but includes other topics concerned with experiment systems and their performance affecting the science measurements. The hydrogen maser is the most accurate and stable clock available. It will be used in future gravitational physics missions to measure relativistic effects such as the second order Doppler effect. The HMC experiment, currently under development at the Smithsonian Astrophysical Observatory (SAO), will test the performance and capability of the hydrogen maser clock for gravitational physics measurements. UAH in collaboration with the SAO science team will study methods to evaluate the behavior and performance of the HMC. The GP-B data analysis developed by the Stanford group involves complicated mathematical operations. This situation led to the idea to investigate alternate and possibly simpler mathematical procedures to extract the GP-B measurements form the data stream. Comparison of different methods would increase the confidence in the selected scheme.
Astrophysical sources of gravitational waves
Energy Technology Data Exchange (ETDEWEB)
Losurdo, G. E-mail: losurdo@galileo.pi.infn.it
2000-05-01
The interferometric detectors of gravitational waves (GW) (such as VIRGO and LIGO) will search for events in a frequency band within a few Hz and a few kHz, where several sources are expected to emit. In this talk we outline briefly the current theoretical knowledge on the emission of GW in events such as the coalescence of compact binaries, the gravitational collapse, the spinning of a neutron stars. Expected amplitudes are compared with the target sensitivity of the VIRGO/LIGO interferometric detectors.
Energy Technology Data Exchange (ETDEWEB)
Leutwyler, H; Mallik, S
1986-12-01
The effective action for fermions moving in external gravitational and gauge fields is analyzed in terms of the corresponding external field propagator. The central object in our approach is the covariant energy-momentum tensor which is extracted from the regular part of the propagator at short distances. It is shown that the Lorentz anomaly, the conformal anomaly and the gauge anomaly can be expressed in terms of the local polynomials which determine the singular part of the propagator. (There are no coordinate anomalies). Except for the conformal anomaly, for which we give explicit representations only in dless than or equal to4, we consider an arbitrary number of dimensions.
Directory of Open Access Journals (Sweden)
Metin SALTIK
1996-03-01
Full Text Available According to classical electromagnetic theory, an accelerated charge or system of charges radiates electromagnetic waves. In a radio transmitter antenna charges are accelerated along the antenna and release electromagnetic waves, which is radiated at the velocity of light in the surrounding medium. All of the radio transmitters work on this principle today. In this study an analogy is established between the principles by which accelerated charge systems markes radiation and the accelerated mass system, and the systems cousing gravitational radiation are investigated.
International Nuclear Information System (INIS)
Turner, E.L.
1989-01-01
The author discusses how gravitational lens studies is becoming a major focus of extragalactic astronomy and cosmology. This review is organized into five parts: an overview of the observational situation, a look at the state of theoretical work on lenses, a detailed look at three recently discovered types of lensing phenomena (luminous arcs, radio rings, quasar-galaxy associations), a review of progress on two old problems in lens studies (deriving unique lens mass distribution models, measurements of differential time delays), and an attempt to look into the future of lens studies
Search for gravitational wave bursts by the network of resonant detectors
Astone, P; Busby, D; Bassan, M; Blair, D G; Bonaldi, M; Bonifazi, P; Carelli, P; Cerdonio, M; Coccia, E; Conti, L; Cosmelli, C; D'Antonio, S; Fafone, V; Falferi, P; Fortini, P; Frasca, S; Hamilton, W O; Heng, I S; Ivanov, E N; Johnson, W W; Locke, C R; Marini, A; Mauceli, E; McHugh, M P; Mezzena, R; Minenkov, Y; Modena, I; Modestino, G; Moleti, A; Ortolan, A; Pallottino, G V; Pizzella, G; Prodi, G A; Quintieri, L; Rocchi, A; Rocco, E; Ronga, F; Salemi, F; Santostasi, G; Taffarello, L; Terenzi, R; Tobar, M E; Vedovato, G; Vinante, A; Visco, M; Vitale, S; Zendri, J P
2002-01-01
The groups operating cryogenic bar detectors of gravitational waves are performing a coordinated search for short signals within the International Gravitational Event Collaboration (IGEC). We review the most relevant aspects of the data analysis, based on a time-coincidence search among triggers from different detectors, and the properties of the data exchanged by each detector under a recently-upgraded agreement. The IGEC is currently analysing the observations from 1997 to 2000, when up to four detectors were operating simultaneously. 10% and 50% of this time period were covered by simultaneous observations, respectively, of at least three or at least two detectors. Typical signal search thresholds were in the range 2-6 10 sup - sup 2 sup 1 /Hz. The coincidences found are within the estimated background, hence improved upper limits on incoming GW (gravitational wave) bursts have been set.
Relic gravitational waves and the generalized second law
International Nuclear Information System (INIS)
Izquierdo, German; Pavon, Diego
2004-01-01
The generalized second law of gravitational thermodynamics is applied to the present era of accelerated expansion of the Universe. In spite of the fact that the entropy of matter and relic gravitational waves inside the event horizon diminish, the mentioned law is fulfilled provided that the expression for the entropy density of the gravitational waves satisfies a certain condition
Directory of Open Access Journals (Sweden)
Igor V. Karyakin
2016-02-01
Full Text Available The 9th ARRCN Symposium 2015 was held during 21st–25th October 2015 at the Novotel Hotel, Chumphon, Thailand, one of the most favored travel destinations in Asia. The 10th ARRCN Symposium 2017 will be held during October 2017 in the Davao, Philippines. International Symposium on the Montagu's Harrier (Circus pygargus «The Montagu's Harrier in Europe. Status. Threats. Protection», organized by the environmental organization «Landesbund für Vogelschutz in Bayern e.V.» (LBV was held on November 20-22, 2015 in Germany. The location of this event was the city of Wurzburg in Bavaria.
2010-03-01
are turning out to be counterproductive because they are culturally anathema (Wollman, 2009). A consideration of psychological tenets by Sigmund ... Freud suggests a principle aspect of dysfunction in collaboration. He reasoned that An Ego governed by social convention and a Superego governed by
Experimental signatures of gravitational wave bursters
International Nuclear Information System (INIS)
Dubath, Florian; Foffa, Stefano; Gasparini, Maria Alice; Maggiore, Michele; Sturani, Riccardo
2005-01-01
Gravitational wave bursters are sources which emit repeatedly bursts of gravitational waves, and have been recently suggested as potentially interesting candidates for gravitational wave (GW) detectors. Mechanisms that could give rise to a GW burster can be found for instance in highly magnetized neutron stars (the 'magnetars' which explain the phenomenon of soft gamma repeaters), in accreting neutron stars and in hybrid stars with a quark core. We point out that these sources have very distinctive experimental signatures. In particular, as already observed in the γ-ray bursts from soft gamma repeaters, the energy spectrum of the events is a power-law, dN∼E -γ dE with γ≅1.6, and they have a distribution of waiting times (the times between one outburst and the next) significantly different from the distribution of uncorrelated events. We discuss possible detection strategies that could be used to search for these events in existing gravitational wave detectors
Cavaglià, M.; Hendry, M.; Ingram, D.; Milde, S.; Reitze, D.; Riles, K.; Schutz, B.; Stuver, A. L.; Summerscales, T.; Thacker, J.; Torres, C. V.; Ugolini, D.; Vallisneri, M.; Zermeno, A.
2008-11-01
The nascent field of gravitational-wave astronomy offers many opportunities for effective and inspirational astronomy outreach. Gravitational waves, the ``ripples in space-time'' predicted by Einstein's theory of General Relativity, are produced by some of the most energetic and dramatic phenomena in the cosmos, including black holes, neutron stars and supernovae. The detection of gravitational waves will help to address a number of fundamental questions in physics, from the evolution of stars and galaxies to the origin of dark energy and the nature of space-time itself. Moreover, the cutting-edge technology developed to search for gravitational waves is pushing back the frontiers of many fields, from lasers and materials science to high performance computing, and thus provides a powerful showcase for the attractions and challenges of a career in science and engineering. For several years a worldwide network of ground-based laser interferometric gravitational-wave detectors has been fully operational, including the two LIGO detectors in the United States. These detectors are already among the most sensitive scientific instruments on the planet and in the next few years their sensitivity will achieve further significant improvement. Those developments promise to open an exciting new window on the universe, heralding the arrival of gravitational-wave astronomy as a revolutionary, new observational field. In this paper we describe the extensive program of public outreach activities already undertaken by the LIGO Scientific Collaboration, and a number of special events which we are planning for IYA2009.
Gravity's kiss the detection of gravitational waves
Collins, Harry
2017-01-01
Scientists have been trying to confirm the existence of gravitational waves for fifty years. Then, in September 2015, came a "very interesting event" (as the cautious subject line in a physicist's email read) that proved to be the first detection of gravitational waves. In Gravity's Kiss, Harry Collins -- who has been watching the science of gravitational wave detection for forty-three of those fifty years and has written three previous books about it -- offers a final, fascinating account, written in real time, of the unfolding of one of the most remarkable scientific discoveries ever made. Predicted by Einstein in his theory of general relativity, gravitational waves carry energy from the collision or explosion of stars. Dying binary stars, for example, rotate faster and faster around each other until they merge, emitting a burst of gravitational waves. It is only with the development of extraordinarily sensitive, highly sophisticated detectors that physicists can now confirm Einstein's prediction. This is...
Sadowski, B.M.; Dittrich, K.; Duysters, G.M.
2003-01-01
The paper examines the extent to which collaboration between large and small companies has been able to deal with the effects of discontinuous technological change. In applying an evolutionary perspective, the paper examines the process by which technological competencies and resources of large
DEFF Research Database (Denmark)
Choi, J.-Y.; Shin, I.-G.; Park, S.-Y.
2012-01-01
☉ is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation...
Prevention of gravitational collapse
International Nuclear Information System (INIS)
Moffat, J.W.; Taylor, J.G.
1981-01-01
We apply a new theory of gravitation to the question of gravitational collapse to show that collapse is prevented in this theory under very reasonable conditions. This result also extends to prevent ultimate collapse of the Universe. (orig.)
Underdevelopment’s gravitation
Directory of Open Access Journals (Sweden)
Marin Dinu
2013-09-01
Full Text Available The energy necessary to escape the gravitational pull of underdevelopment and to enter an evolutional trajectory dependent on the gravitational pull of development is unintelligible in economic terms.
Present and Future of Gravitational Wave Experiments
CERN. Geneva. Audiovisual Unit
2002-01-01
The status of the present detectors and of the main future projects will be reported. The recent results of a search for gravitational wave bursts, using the data collected by the ROG Collaboration cryogenic bar detectors EXPLORER (at CERN) and NAUTILUS (at LNF), will be discussed.
PREFACE: 8th Edoardo Amaldi Conference on Gravitational Waves
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
Ridgely, Charles T.
2011-01-01
When two gravitating bodies reside in a material medium, Newton's law of universal gravitation must be modified to account for the presence of the medium. A modified expression of Newton's law is known in the literature, but lacks a clear connection with existing gravitational theory. Newton's law in the presence of a homogeneous material medium…
Detection of gravitational radiation
Energy Technology Data Exchange (ETDEWEB)
Holten, J.W. van [ed.
1994-12-31
In this report the main contributions presented at the named symposium are collected. These concern astrophysical sources of gravitational radiation, ultracryogenic gravitational wave experiments, read out and data analysis of gravitational wave antennas, cryogenic aspects of large mass cooling to mK temperatures, and metallurgical and engineering aspects of large Cu structure manufacturing. (HSI).
Detection of gravitational radiation
International Nuclear Information System (INIS)
Holten, J.W. van
1994-01-01
In this report the main contributions presented at the named symposium are collected. These concern astrophysical sources of gravitational radiation, ultracryogenic gravitational wave experiments, read out and data analysis of gravitational wave antennas, cryogenic aspects of large mass cooling to mK temperatures, and metallurgical and engineering aspects of large Cu structure manufacturing. (HSI)
Relativity theory and gravitation
International Nuclear Information System (INIS)
Bondi, H.
1986-01-01
The paper on relativity theory and gravitation is presented as a preface to the first of the articles submitted to the Journal on general relativity. Newtonian gravitation and and observation, relativity, and the sources of the gravitational field, are all discussed. (UK)
Gravitation and bilocal field theory
International Nuclear Information System (INIS)
Vollendorf, F.
1975-01-01
The starting point is the conjecture that a field theory of elementary particles can be constructed only in a bilocal version. Thus the 4-dimensional space time has to be replaced by the 8-dimensional manifold R 8 of all ordered pairs of space time events. With special reference to the Schwarzschild metric it is shown that the embedding of the time space into the manifold R 8 yields a description of the gravitational field. (orig.) [de
Energy Technology Data Exchange (ETDEWEB)
Yonetoku, Daisuke; Sawano, Tatsuya; Toyanago, Asuka [College of Science and Engineering, School of Mathematics and Physics, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192 (Japan); Nakamura, Takashi [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Takahashi, Keitaro, E-mail: yonetoku@astro.s.kanazawa-u.ac.jp, E-mail: takashi@tap.scphys.kyoto-u.ac.jp [Faculty of Science, Kumamoto University, Kurokami, Kumamoto 860-8555 (Japan)
2014-07-01
Using 72 short gamma-ray bursts (SGRBs) with well determined spectral data observed by BATSE, we determine their redshift and luminosity by applying the E{sub p} -L{sub p} correlation for SGRBs found by Tsutsui et al. For 53 SGRBs with an observed flux brighter than 4 × 10{sup –6} erg cm{sup –2} s{sup –1}, the cumulative redshift distribution up to z = 1 agrees well with that of 22 Swift SGRBs. This suggests that the redshift determination by the E{sub p} -L{sub p} correlation for SGRBs works well. The minimum event rate at z = 0 is estimated as R{sub on−axis}{sup min}=6.3{sub −3.9}{sup +3.1}× 10{sup −10} events Mpc{sup −3} yr{sup −1}, so that the minimum beaming angle is 0.°6-7.°8 assuming a merging rate of 10{sup –7}- 4 × 10{sup –6} events Mpc{sup –3} yr{sup –1} suggested from the binary pulsar data. Interestingly, this angle is consistent with that for SGRB 130603B of ∼4°-8°. On the other hand, if we assume a beaming angle of ∼6° suggested from four SGRBs with the observed beaming angle value, then the minimum event rate including off-axis SGRBs is estimated as R{sub all}{sup min}=1.15{sub −0.66}{sup +0.56} × 10{sup −7} events Mpc{sup −3} yr{sup −1}. If SGRBs are induced by the coalescence of binary neutron stars (NSs) and/or black holes (BHs), then this event rate leads to a minimum gravitational-wave detection rate of 3.8{sub −2.2}{sup +1.8} (146{sub −83}{sup +71}) events yr{sup −1} for an NS-NS (NS-BH) binary, respectively, by a worldwide network with KAGRA, advanced-LIGO, advanced-VIRGO, and GEO.
Sources and astrophysical effects of gravitational waves
International Nuclear Information System (INIS)
Rees, M.J.
1974-01-01
The probable sources of short intense gravitational wave emissions are discussed and it is concluded, on the basis of current astrophysical ideas, that the number of events detected by an apparatus such as Weber's would not be more than one pulse par century. Some proposed explanations of a higher event rate are examined briefly but it is suggested that the sensitivity would probably have to be improved by a factor 10 8 if a few events per year due to extragalactic supernovae are to be detectable. The article concludes by mentioning several other kinds of gravitational waves of potential interest in astrophysics
Astrometric Observation of MACHO Gravitational Microlensing
Boden, A. F.; Shao, M.; Van Buren, D.
1997-01-01
This paper discusses the prospects for astrometric observation of MACHO gravitational microlensing events. We derive the expected astrometric observables for a simple microlensing event assuming a dark MACHO, and demonstrate that accurate astrometry can determine the lens mass, distance, and proper motion in a very general fashion.
Congratulations on the direct detection of gravitational waves
2016-01-01
This week saw the announcement of an extraordinary physics result: the first direct detection of gravitational waves by the LIGO Scientific Collaboration, which includes the GEO team, and the Virgo Collaboration, using the twin Laser Interferometer Gravitational-wave Observatory (LIGO) detectors located in Livingston, Louisiana, and Hanford, Washington, USA. Albert Einstein predicted gravitational waves in a paper published 100 years ago in 1916. They are a natural consequence of the theory of general relativity, which describes the workings of gravity and was published a few months earlier. Until now, they have remained elusive. Gravitational waves are tiny ripples in space-time produced by violent gravitational phenomena. Because the fractional change in the space-time geometry can be at the level of 10-21 or smaller, extremely sophisticated, high-sensitivity instruments are needed to detect them. Recently, the Advanced LIGO detector increased its sensitivity by alm...
DEFF Research Database (Denmark)
Urowitz, M B; Gladman, D D; Anderson, N M
2016-01-01
OBJECTIVE: To describe the frequency of myocardial infarction (MI) prior to the diagnosis of systemic lupus erythematosus (SLE) and within the first 2 years of follow-up. METHODS: The systemic lupus international collaborating clinics (SLICC) atherosclerosis inception cohort enters patients within......% CI 2.38 to 23.57) remained significant risk factors. CONCLUSIONS: In some patients with lupus, MI may develop even before the diagnosis of SLE or shortly thereafter, suggesting that there may be a link between autoimmune inflammation and atherosclerosis....
Theory of gravitational interactions
Gasperini, Maurizio
2017-01-01
This is the second edition of a well-received book that is a modern, self-contained introduction to the theory of gravitational interactions. The new edition includes more details on gravitational waves of cosmological origin, the so-called brane world scenario, and gravitational time-delay effects. The first part of the book follows the traditional presentation of general relativity as a geometric theory of the macroscopic gravitational field, while the second, more advanced part discusses the deep analogies (and differences) between a geometric theory of gravity and the “gauge” theories of the other fundamental interactions. This fills a gap within the traditional approach to general relativity which usually leaves students puzzled about the role of gravity. The required notions of differential geometry are reduced to the minimum, allowing room for aspects of gravitational physics of current phenomenological and theoretical interest, such as the properties of gravitational waves, the gravitational inter...
DEFF Research Database (Denmark)
Choi, J.-Y; Shin, I.-G; Han, C.
2012-01-01
between two cusps of an astroid-shaped caustic. We demonstrate the degeneracy for two high-magnification events of OGLE-2011-BLG-0526 and OGLE-2011-BLG-0950/MOA-2011-BLG-336. For OGLE-2011-BLG-0526, the χ2 difference between the planetary and binary model is ~3, implying that the degeneracy is very severe...... distinguished due to the essentially different magnification pattern around caustics. In this paper, we present a case of central perturbations for which it is difficult to distinguish the planetary and binary interpretations. The peak of a lensing light curve affected by this perturbation appears to be blunt...... and flat. For a planetary case, this perturbation occurs when the source trajectory passes the negative perturbation region behind the back end of an arrowhead-shaped central caustic. For a binary case, a similar perturbation occurs for a source trajectory passing through the negative perturbation region...
Guglielmi, Valeria; Vulink, Nienke C. C.; Denys, Damiaan; Wang, Ying; Samuels, Jack F.; Nestadt, Gerald
2014-01-01
Women with obsessive-compulsive disorder (OCD) often report that symptoms first appear or exacerbate during reproductive cycle events; however, little is known about these relationships. The goals of this study were to examine, in a US and a European female OCD sample, onset and exacerbation of OCD
Guglielmi, Valeria; Vulink, Nienke C C; Denys, Damiaan; Wang, Ying; Samuels, Jack F; Nestadt, Gerald
2014-12-01
Women with obsessive-compulsive disorder (OCD) often report that symptoms first appear or exacerbate during reproductive cycle events; however, little is known about these relationships. The goals of this study were to examine, in a US and a European female OCD sample, onset and exacerbation of OCD in reproductive cycle events, and to investigate the likelihood of repeat exacerbation in subsequent pregnancies and postpartum periods. Five hundred forty-two women (United States, n = 352; Dutch, n = 190) who met DSM-IV criteria for OCD, completed self-report questionnaires designed to assess OCD onset and symptom exacerbation associated with reproductive events. OCD onset occurred within 12 months after menarche in 13.0%, during pregnancy in 5.1%, at postpartum in 4.7%, and at menopause in 3.7%. Worsening of pre-existing OCD was reported by 37.6% of women at premenstruum, 33.0% during pregnancy, 46.6% postpartum, and 32.7% at menopause. Exacerbation in first pregnancy was significantly associated with exacerbation in second pregnancy (OR = 10.82, 95% CI 4.48-26.16), as was exacerbation in first postpartum with exacerbation in second postpartum (OR = 6.86, 95% CI 3.27-14.36). Results were replicated in both samples. Reproductive cycle events are periods of increased risk for onset and exacerbation of OCD in women. The present study is the first to provide significant evidence that exacerbation in or after first pregnancy is a substantial risk factor for exacerbation in or after a subsequent pregnancy. Further research is needed to identify factors related to exacerbation, so that physicians may provide appropriate recommendations to women regarding clinical issues involving OCD and reproductive cycle events. © 2014 Wiley Periodicals, Inc.
Gravitational waves from inflation
International Nuclear Information System (INIS)
Guzzetti, M.C.; Bartolo, N.; Liguori, M.; Matarrese, S.
2016-01-01
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 ηT. 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.
Transient multimessenger astronomy with gravitational waves
International Nuclear Information System (INIS)
Marka, S
2011-01-01
Comprehensive multimessenger astronomy with gravitational waves is a pioneering field bringing us interesting results and presenting us with exciting challenges for the future. During the era of the operation of advanced interferometric gravitational wave detectors, we will have the opportunity to investigate sources of gravitational waves that are also expected to be observable through other messengers, such as gamma rays, x-rays, optical, radio, and/or neutrino emission. Multimessenger searches for gravitational waves with the LIGO-GEO600-Virgo interferometer network have already produced insights on cosmic events and it is expected that the simultaneous observation of electromagnetic or neutrino emission could be a crucial aspect for the first direct detection of gravitational waves in the future. Trigger time, direction and expected frequency range enhances our ability to search for gravitational wave signatures with amplitudes closer to the noise floor of the detector. Furthermore, multimessenger observations will enable the extraction of otherwise unaccessible scientific insight. We summarize the status of transient multimessenger detection efforts as well as mention some of the open questions that might be resolved by advanced or third generation gravitational wave detector networks.
Upper limits from the LIGO and TAMA detectors on the rate of gravitational-wave bursts
International Nuclear Information System (INIS)
Abbott, B.; Abbott, R.; Adhikari, R.; Agresti, J.; Anderson, S.B.; Araya, M.; Armandula, H.; Asiri, F.; Barish, B.C.; Barnes, M.; Barton, M.A.; Bhawal, B.; Billingsley, G.; Black, E.; Blackburn, K.; Bork, R.; Brown, D. A.; Busby, D.; Cardenas, L.; Chandler, A.
2005-01-01
We report on the first joint search for gravitational waves by the TAMA and LIGO collaborations. We looked for millisecond-duration unmodeled gravitational-wave bursts in 473 hr of coincident data collected during early 2003. No candidate signals were found. We set an upper limit of 0.12 events per day on the rate of detectable gravitational-wave bursts, at 90% confidence level. From software simulations, we estimate that our detector network was sensitive to bursts with root-sum-square strain amplitude above approximately 1-3x10 -19 Hz -1/2 in the frequency band 700-2000 Hz. We describe the details of this collaborative search, with particular emphasis on its advantages and disadvantages compared to searches by LIGO and TAMA separately using the same data. Benefits include a lower background and longer observation time, at some cost in sensitivity and bandwidth. We also demonstrate techniques for performing coincidence searches with a heterogeneous network of detectors with different noise spectra and orientations. These techniques include using coordinated software signal injections to estimate the network sensitivity, and tuning the analysis to maximize the sensitivity and the livetime, subject to constraints on the background
Anisotropic gravitational instability
International Nuclear Information System (INIS)
Polyachenko, V.L.; Fridman, A.M.
1988-01-01
Exact solutions of stability problems are obtained for two anisotropic gravitational systems of different geometries - a layer of finite thickness at rest and a rotating cylinder of finite radius. It is shown that the anisotropic gravitational instability which develops in both cases is of Jeans type. However, in contrast to the classical aperiodic Jeans instability, this instability is oscillatory. The physics of the anisotropic gravitational instability is investigated. It is shown that in a gravitating layer this instability is due, in particular, to excitation of previously unknown interchange-Jeans modes. In the cylinder, the oscillatory Jeans instability is associated with excitation of a rotational branch, this also being responsible for the beam gravitational instability. This is the reason why this instability and the anisotropic gravitational instability have so much in common
CERN. Geneva HR-RFA
2006-01-01
We will present a brief introduction to the physics of gravitational waves and their properties. We will review potential astrophysical sources of gravitational waves, and the physics and astrophysics that can be learned from their study. We will survey the techniques and technologies for detecting gravitational waves for the first time, including bar detectors and broadband interferometers, and give a brief status report on the international search effort.
CERN. Geneva
2006-01-01
Gravitational wave astronomy is expected to become an observational field within the next decade. First direct detection of gravitational waves is possible with existing terrestrial-based detectors, and highly probable with proposed upgrades. In this three-part lecture series, we give an overview of the field, including material on gravitional wave sources, detection methods, some details of interferometric detectors, data analysis methods, and current results from observational data-taking runs of the LIGO and GEO projects.
International Nuclear Information System (INIS)
Ridgely, Charles T
2011-01-01
When two gravitating bodies reside in a material medium, Newton's law of universal gravitation must be modified to account for the presence of the medium. A modified expression of Newton's law is known in the literature, but lacks a clear connection with existing gravitational theory. Newton's law in the presence of a homogeneous material medium is herein derived on the basis of classical, Newtonian gravitational theory and by a general relativistic use of Archimedes' principle. It is envisioned that the techniques presented herein will be most useful to graduate students and those undergraduate students having prior experience with vector analysis and potential theory.
Hoffmann, William F
1964-01-01
Remarks on the observational basis of general relativity ; Riemannian geometry ; gravitation as geometry ; gravitational waves ; Mach's principle and experiments on mass anisotropy ; the many faces of Mach ; the significance for the solar system of time-varying gravitation ; relativity principles and the role of coordinates in physics ; the superdense star and the critical nucleon number ; gravitation and light ; possible effects on the solar system of φ waves if they exist ; the Lyttleton-Bondi universe and charge equality ; quantization of general relativity ; Mach's principle as boundary condition for Einstein's equations.
Multiply imaged Transient Events in Cluster Lenses
Narasimha, Delampady
2018-04-01
ARIES had a successful gravitational microlens project during 1998-2002. A similar monitor for Transient Events in galaxies at high redshift lensed by rich galaxy-clusters provides a challenging possibility with important cosmological implications. Rich galaxy-clusters at intermediate redshifts are powerful gravitational lenses which produce multiple images, in the shape of giant arcs of 5-20" extent, of distant background galaxies in their field. Weak lens shear of the background galaxy distribution can reliably trace the lens mass profile. Multiple images of supernovae or GRBs in the background galaxies can be recorded in a systematic monitor of the system. An unlensed high redshift supernova might not be observable, but when lensed by a galaxy-cluster, it will stand out because the point event brightens relative to the host. The color profile of a high redshift lensed point event will be much more reliable than an unlensed one due to much less host contamination. An estimate of the time delay enables observation of the full light curve of the subsequent images of the event. ARIES can have outside collaboration for multiband simultaneous lightcurves of other images. The measured time delay and position of images of the transient event provide better cosmological constraints including distance scale of the Universe. The Devasthal telescope can detect one or more events by monitoring half a dozen cluster fields over three years time.
Gravitational effects in field gravitation theory
International Nuclear Information System (INIS)
Denisov, V.I.; Logunov, A.A.; Mestvirishvili, M.A.; Vlasov, A.A.
1979-01-01
The possibilities to describe various gravitation effects of field gravitation theory (FGT) are considered. Past-Newtonian approximation of the FGT has been constructed and on the basis of this approximation it has been shown that the field theory allows one to describe the whole set of experimental facts. The comparison of post-Newtonian parameters in FGT with those in the Einstein's theory makes it clear that these two; theories are undistinguishable from the viewpoint of any experiments, realized with post-Newtonian accuracy. Gravitational field of an island type source with spherically symmetrical distribution of matter and unstationary homogeneous model of Universe, which allows to describe the effect of cosmological red shift, are considered
R. Vlokh; M. Kostyrko
2006-01-01
Nonlinear effect of the gravitation field of spherically symmetric mass on the gravitational coefficient G has been analysed. In frame of the approaches of parametric optics and gravitation nonlinearity we have shown that the gravitation field of spherically symmetric mass can lead to changes in the gravitational coefficient G.
On the relativistic particle dynamics in external gravitational fields
International Nuclear Information System (INIS)
Kuz'menkov, L.S.; Naumov, N.D.
1977-01-01
On the base of the Riemann metrics of an event space, leading to the Newton mechanics at nonrelativistic velocities and not obligatory weak gravitational fields relativistic particle dynamics in external gravitation fields has been considered. Found are trajectories, motion laws and light ray equations for the homogeneous and Newton fields
Relativistic gravitation theory
International Nuclear Information System (INIS)
Logunov, A.A.; Mestvirishvili, M.A.
1984-01-01
On the basis of the special relativity and geometrization principle a relativistic gravitation theory (RGT) is unambiguously constructed with the help of a notion of a gravitational field as a physical field in Faraday-Maxwell spirit, which posesses energy momentum and spins 2 and 0. The source of gravitation field is a total conserved energy-momentum tensor for matter and for gravitation field in Minkowski space. In the RGT conservation laws for the energy momentum and angular momentum of matter and gravitational field hold rigorously. The theory explains the whole set of gravitation experiments. Here, due to the geometrization principle the Riemannian space is of a field origin since this space arises effectively as a result of the gravitation field origin since this space arises effectively as a result of the gravitation field action on the matter. The RGT astonishing prediction is that the Universe is not closed but ''flat''. It means that in the Universe there should exist a ''missing'' mass in some form of matter
Those Elusive Gravitational Waves
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)
Gravitationally coupled electroweak monopole
Energy Technology Data Exchange (ETDEWEB)
Cho, Y.M., E-mail: ymcho7@konkuk.ac.kr [Administration Building 310-4, Konkuk University, Seoul 143-701 (Korea, Republic of); School of Physics and Astronomy, Seoul National University, Seoul 151-742 (Korea, Republic of); Kimm, Kyoungtae [Faculty of Liberal Education, Seoul National University, Seoul 151-747 (Korea, Republic of); Yoon, J.H. [Department of Physics, College of Natural Sciences, Konkuk University, Seoul 143-701 (Korea, Republic of)
2016-10-10
We present a family of gravitationally coupled electroweak monopole solutions in Einstein–Weinberg–Salam theory. Our result confirms the existence of globally regular gravitating electroweak monopole which changes to the magnetically charged black hole as the Higgs vacuum value approaches to the Planck scale. Moreover, our solutions could provide a more accurate description of the monopole stars and magnetically charged black holes.
Looking towards gravitational wave detection
Barsotti, Lisa
2009-05-01
It is an exciting time in gravitational wave research. The first generation ground detectors, which aim to detect gravitational waves in the audio-frequency region, have been successfully operated at their design sensitivity. One integrated year of coincident data from the three LIGO interferometers in United States has been collected between 2005 and 2007, in partial coincidence with the two European detectors, VIRGO and GEO. All the detectors are currently being upgraded, and they will come back on-line in the next few months with a factor 2 better sensitivity. A major upgrade of LIGO and VIRGO, scheduled to happen immediately after their upcoming science runs, will bring on-line second generation detectors 4 years from now. Their sensitivity is designed to be 10 times better than the first generation detectors, resulting in an expected event rate of at least a few per year. Looking farther into the future, space-based detectors such as LISA propose to cover a lower range of frequencies which are inaccessible on Earth, enhancing the opportunity of understanding our Universe trough gravitational waves.
Caudell, David; Harper, David P; Novak, Rachel L; Pierce, Rachel M; Slape, Christopher; Wolff, Linda; Aplan, Peter D
2010-02-11
The t(10;11) translocation results in a CALM-AF10 fusion gene in a subset of leukemia patients. Expression of a CALM-AF10 transgene results in leukemia, with prolonged latency and incomplete penetrance, suggesting that additional events are necessary for leukemic transformation. CALM-AF10 mice infected with the MOL4070LTR retrovirus developed acute leukemia, and ligation-mediated polymerase chain reaction was used to identify retroviral insertions at 19 common insertion sites, including Zeb2, Nf1, Mn1, Evi1, Ift57, Mpl, Plag1, Kras, Erg, Vav1, and Gata1. A total of 26% (11 of 42) of the mice had retroviral integrations near Zeb2, a transcriptional corepressor leading to overexpression of the Zeb2-transcript. A total of 91% (10 of 11) of mice with Zeb2 insertions developed B-lineage acute lymphoblastic leukemia, suggesting that Zeb2 activation promotes the transformation of CALM-AF10 hematopoietic precursors toward B-lineage leukemias. More than half of the mice with Zeb2 integrations also had Nf1 integrations, suggesting cooperativity among CALM-AF10, Zeb2, and Ras pathway mutations. We searched for Nras, Kras, and Ptpn11 point mutations in the CALM-AF10 leukemic mice. Three mutations were identified, all of which occurred in mice with Zeb2 integrations, consistent with the hypothesis that Zeb2 and Ras pathway activation promotes B-lineage leukemic transformation in concert with CALM-AF10.
A gravitational entropy proposal
International Nuclear Information System (INIS)
Clifton, Timothy; Tavakol, Reza; Ellis, George F R
2013-01-01
We propose a thermodynamically motivated measure of gravitational entropy based on the Bel–Robinson tensor, which has a natural interpretation as the effective super-energy–momentum tensor of free gravitational fields. The specific form of this measure differs depending on whether the gravitational field is Coulomb-like or wave-like, and reduces to the Bekenstein–Hawking value when integrated over the interior of a Schwarzschild black hole. For scalar perturbations of a Robertson–Walker geometry we find that the entropy goes like the Hubble weighted anisotropy of the gravitational field, and therefore increases as structure formation occurs. This is in keeping with our expectations for the behaviour of gravitational entropy in cosmology, and provides a thermodynamically motivated arrow of time for cosmological solutions of Einstein’s field equations. It is also in keeping with Penrose’s Weyl curvature hypothesis. (paper)
Detections of the Gravitational Waves
Directory of Open Access Journals (Sweden)
José Maria Filardo Bassalo
2016-12-01
Full Text Available On February 11, 2016, during a conference held at the National Science Foundation (NSF, in Washington, D.C., the American physicist David Reitze, Executive Director of the Laser Interferometer Gravitacional-Wave Observatory (LIGO announced that it had been observed on September 14, 2015 Gravitational Waves (GW. This event was named GW150914. A second observation was also done by the LIGO on December 26, 2015 named GW151226. The signals of these two events are similar and are due to the coalescence of a binary black holes (BH. The GW sources are distant, respectively, of ~ 410 Mpc and ~ 440 Mpc from the Earth. To understand the significance of this extraordinary events we will make a historical summary of the GW and the BH.
DESGW: Optical Follow-up of BBH LIGO-Virgo Events with DECam
Energy Technology Data Exchange (ETDEWEB)
Butler, Robert E. [Indiana U.; Soares-Santos, M. [Brandeis U.; Annis, j. [Fermilab; Herner, K. [Fermilab
2017-12-14
The DESGW program is a collaboration between members of the Dark Energy Survey, the wider astronomical community, and the LIGO-Virgo Collaboration to search for optical counterparts of gravitational wave events, such as those expected from binary neutron star mergers or neutron star-black hole mergers. While binary black hole (BBH) events are not expected to produce an electromagnetic (EM) signature, emission is certainly not impossible. The DESGW program has performed follow-up observations of four BBH events detected by LIGO in order to search for any possible EM counterpart. Failure to nd such counterparts is still relevant in that it produces limits on optical emission from such events. This is a review of follow-up results from O1 BBH events and a discussion of the status of ongoing uniform re-analysis of all BBH events that DESGW has followed up to date.
Relativistic theory of gravitation
International Nuclear Information System (INIS)
Logunov, A.A.; Mestvirishvilli, M.A.
1985-01-01
In the present paper a relativistic theory of gravitation (RTG) is constructed in a unique way on the basis of the special relativity and geometrization principle. In this, a gravitational field is treated as the Faraday-Maxwell spin-2 and spin-0 physical field possessing energy and momentum. The source of a gravitational field is the total conserved energy-momentum tensor of matter and of a gravitational field in Minkowski space. In the RTG, the conservation laws are strictly fulfilled for the energy-momentum and for the angular momentum of matter and a gravitational field. The theory explains the whole available set of experiments on gravitation. In virtue of the geometrization principle, the Riemannian space in our theory is of field origin, since it appears as an effective force space due to the action of a gravitational field on matter. The RTg leads to an exceptionally strong prediction: The Universe is not closed but just ''flat''. This suggests that in the Universe a ''hidden mass'' should exist in some form of matter
LIGO GW150914 and GW151226 gravitational wave detection and generalized gravitation theory (MOG
Directory of Open Access Journals (Sweden)
J.W. Moffat
2016-12-01
Full Text Available The nature of gravitational waves in a generalized gravitation theory is investigated. The linearized field equations and the metric tensor quadrupole moment power and the decrease in radius of an inspiralling binary system of two compact objects are derived. The generalized Kerr metric describing a spinning black hole is determined by its mass M and the spin parameter a=cS/GM2. The LIGO-Virgo collaboration data is fitted with smaller binary black hole masses in agreement with the current electromagnetic, observed X-ray binary upper bound for a black hole mass, M≲10M⊙.
International Nuclear Information System (INIS)
Tevikyan, R.V.
1986-01-01
This paper presents equations that describe particles with spins s = 0, 1/2, 1 completely and which also describe 2s + 2 limiting fields as E → ∞. It is shown that the ordinary Hilbert-Einstein action for the gravitation field must be augmented by the action for the Bose vacuum field. This means that one must introduce in the gravitational equations a cosmological term proportional to the square of the strength of the Bose vacuum field. It is shown that the theory of gravitation describes three realities: matter, field, and vacuum field. A new form of matter--the vacuum field--is introduced into field theory
Gravitational radiation reaction
International Nuclear Information System (INIS)
Tanaka, Takahiro
2006-01-01
We give a short personally-biased review on the recent progress in our understanding of gravitational radiation reaction acting on a point particle orbiting a black hole. The main motivation of this study is to obtain sufficiently precise gravitational waveforms from inspiraling binary compact starts with a large mass ratio. For this purpose, various new concepts and techniques have been developed to compute the orbital evolution taking into account the gravitational self-force. Combining these ideas with a few supplementary new ideas, we try to outline a path to our goal here. (author)
Presenting Newtonian gravitation
International Nuclear Information System (INIS)
Counihan, Martin
2007-01-01
The basic principles of the Newtonian theory of gravitation are presented in a way which students may find more logically coherent, mathematically accessible and physically interesting than other approaches. After giving relatively simple derivations of the circular hodograph and the elliptical orbit from the inverse-square law, the concept of gravitational energy is developed from vector calculus. It is argued that the energy density of a gravitational field may reasonably be regarded as -g 2 /8πG, and that the inverse-square law may be replaced by a Schwarzschild-like force law without the need to invoke non-Euclidean geometry
Gravitational entropy of nonstationary black holes and spherical shells
International Nuclear Information System (INIS)
Hiscock, W.A.
1989-01-01
The problem of defining the gravitational entropy of a nonstationary black hole is considered in a simple model consisting of a spherical shell which collapses into a preexisting black hole. The second law of black-hole mechanics strongly suggests identifying one-quarter of the area of the event horizon as the gravitational entropy of the system. It is, however, impossible to accurately locate the position of the global event horizon using only local measurements. In order to maintain a local thermodynamics, it is suggested that the entropy of the black hole be identified with one-quarter the area of the apparent horizon. The difference between the event-horizon entropy (to the extent it can be determined) and the apparent-horizon entropy may then be interpreted as the gravitational entropy of the collapsing shell. The total (event-horizon) gravitational entropy evolves in a smooth (C 0 ) fashion, even in the presence of δ-functional shells of matter
Search for Gravitational Wave Counterparts with Fermi GBM
Hui, C. M.
2017-01-01
The progenitor of short gamma-ray bursts (GRBs) is believed to be the merger of two compact objects. This type of events will also produce gravitational waves. Since the gravitational waves discovery by LIGO, the search for a joint detection with an electromagnetic counterpart has been ongoing. Fermi GBM detects approximately 40 short GRBs per year, and we have been expanding our search looking for faint events in the GBM data that did not trigger onboard.
On the quantum corrected gravitational collapse
International Nuclear Information System (INIS)
Torres, Ramón; Fayos, Francesc
2015-01-01
Based on a previously found general class of quantum improved exact solutions composed of non-interacting (dust) particles, we model the gravitational collapse of stars. As the modeled star collapses a closed apparent 3-horizon is generated due to the consideration of quantum effects. The effect of the subsequent emission of Hawking radiation related to this horizon is taken into consideration. Our computations lead us to argue that a total evaporation could be reached. The inferred global picture of the spacetime corresponding to gravitational collapse is devoid of both event horizons and shell-focusing singularities. As a consequence, there is no information paradox and no need of firewalls
On the quantum corrected gravitational collapse
Directory of Open Access Journals (Sweden)
Ramón Torres
2015-07-01
Full Text Available Based on a previously found general class of quantum improved exact solutions composed of non-interacting (dust particles, we model the gravitational collapse of stars. As the modeled star collapses a closed apparent 3-horizon is generated due to the consideration of quantum effects. The effect of the subsequent emission of Hawking radiation related to this horizon is taken into consideration. Our computations lead us to argue that a total evaporation could be reached. The inferred global picture of the spacetime corresponding to gravitational collapse is devoid of both event horizons and shell-focusing singularities. As a consequence, there is no information paradox and no need of firewalls.
On the quantum corrected gravitational collapse
Torres, Ramón; Fayos, Francesc
2015-07-01
Based on a previously found general class of quantum improved exact solutions composed of non-interacting (dust) particles, we model the gravitational collapse of stars. As the modeled star collapses a closed apparent 3-horizon is generated due to the consideration of quantum effects. The effect of the subsequent emission of Hawking radiation related to this horizon is taken into consideration. Our computations lead us to argue that a total evaporation could be reached. The inferred global picture of the spacetime corresponding to gravitational collapse is devoid of both event horizons and shell-focusing singularities. As a consequence, there is no information paradox and no need of firewalls.
International Nuclear Information System (INIS)
Yilmaz, H.
1975-01-01
Schwinger's source theory is applied to the problem of gravitation and its quantization. It is shown that within the framework of a flat-space the source theory implementation leads to a violation of probability. To avoid the difficulty one must introduce a curved space-time hence the source concept may be said to necessitate the transition to a curved-space theory of gravitation. It is further shown that the curved-space theory of gravitation implied by the source theory is not equivalent to the conventional Einstein theory. The source concept leads to a different theory where the gravitational field has a stress-energy tensor t/sup nu//sub mu/ which contributes to geometric curvatures
Gravitational lensing of quasars
Eigenbrod, Alexander
2013-01-01
The universe, in all its richness, diversity and complexity, is populated by a myriad of intriguing celestial objects. Among the most exotic of them are gravitationally lensed quasars. A quasar is an extremely bright nucleus of a galaxy, and when such an object is gravitationally lensed, multiple images of the quasar are produced – this phenomenon of cosmic mirage can provide invaluable insights on burning questions, such as the nature of dark matter and dark energy. After presenting the basics of modern cosmology, the book describes active galactic nuclei, the theory of gravitational lensing, and presents a particular numerical technique to improve the resolution of astronomical data. The book then enters the heart of the subject with the description of important applications of gravitational lensing of quasars, such as the measurement of the famous Hubble constant, the determination of the dark matter distribution in galaxies, and the observation of the mysterious inner parts of quasars with much higher r...
Gravitational Waves and Neutrinos
Sturani, Riccardo
2018-01-01
We give an overview about the recent detection of gravitational waves by the Advanced LIGO first and second observing runs and by Advanced Virgo, with emphasis on the prospects for multi-messenger astronomy involving neutrinos detections.
Listening music of gravitation
International Nuclear Information System (INIS)
Anon.
2001-01-01
Achievements of precision experiments in Japan (TAMA project) and USA (LIGO Laboratory) in the field of registration of gravitation waves using interferometric gravitational wave detectors are described. Works of the GEO groups in Hannover (Germany) and Vigro (Italy) are noted. Interferometer operation in synchronization during 160 hours demonstrating viability of the technique and its reliability is recorded. Advances in the field of the data analysis with the aim of recording of cosmic signal from noise of the interferometer are noted [ru
Romero, Gustavo E.
2017-01-01
I discuss the recent claims made by Mario Bunge on the philosophical implications of the discovery of gravitational waves. I think that Bunge is right when he points out that the detection implies the materiality of spacetime, but I reject his identification of spacetime with the gravitational field. I show that Bunge's analysis of the spacetime inside a hollow sphere is defective, but this in no way affects his main claim.
Directory of Open Access Journals (Sweden)
Stavroulakis N.
2008-04-01
Full Text Available The equations of gravitation together with the equations of electromagnetism in terms of the General Theory of Relativity allow to conceive an interdependence between the gravitational field and the electromagnetic field. However the technical difficulties of the relevant problems have precluded from expressing clearly this interdependence. Even the simple problem related to the field generated by a charged spherical mass is not correctly solved. In the present paper we reexamine from the outset this problem and propose a new solution.
Gravitationally confined relativistic neutrinos
Vayenas, C. G.; Fokas, A. S.; Grigoriou, D.
2017-09-01
Combining special relativity, the equivalence principle, and Newton’s universal gravitational law with gravitational rather than rest masses, one finds that gravitational interactions between relativistic neutrinos with kinetic energies above 50 MeV are very strong and can lead to the formation of gravitationally confined composite structures with the mass and other properties of hadrons. One may model such structures by considering three neutrinos moving symmetrically on a circular orbit under the influence of their gravitational attraction, and by assuming quantization of their angular momentum, as in the Bohr model of the H atom. The model contains no adjustable parameters and its solution, using a neutrino rest mass of 0.05 eV/c2, leads to composite state radii close to 1 fm and composite state masses close to 1 GeV/c2. Similar models of relativistic rotating electron - neutrino pairs give a mass of 81 GeV/c2, close to that of W bosons. This novel mechanism of generating mass suggests that the Higgs mass generation mechanism can be modeled as a latent gravitational field which gets activated by relativistic neutrinos.
Relativistic theory of gravitation
International Nuclear Information System (INIS)
Logunov, A.A.; Mestvirishvili, M.A.
1986-01-01
In the present paper a relativistic theory of gravitation (RTG) is unambiguously constructed on the basis of the special relativity and geometrization principle. In this a gravitational field is treated as the Faraday--Maxwell spin-2 and spin-0 physical field possessing energy and momentum. The source of a gravitational field is the total conserved energy-momentum tensor of matter and of a gravitational field in Minkowski space. In the RTG the conservation laws are strictly fulfilled for the energy-moment and for the angular momentum of matter and a gravitational field. The theory explains the whole available set of experiments on gravity. By virtue of the geometrization principle, the Riemannian space in our theory is of field origin, since it appears as an effective force space due to the action of a gravitational field on matter. The RTG leads to an exceptionally strong prediction: The universe is not closed but just ''flat.'' This suggests that in the universe a ''missing mass'' should exist in a form of matter
Optical follow-up of gravitational wave triggers with DECam
Energy Technology Data Exchange (ETDEWEB)
Herner, K.; Annis, J.; Berger, E.; Brout, D.; Butler, R.; Chen, H.; Cowperthwaite, P.; Diehl, H.; Doctor, Z.; Drlica-Wagner, A.; Farr, B.; Finley, D.; Frieman, J.; Holz, D.; Kessler, R.; Lin, H.; Marriner, J.; Nielsen, E.; Palmese, A.; Sako, M.; Soares-Santos, M.; Sobreira, F.; Yanny, B.
2017-10-01
Gravitational wave (GW) events have several possible progenitors, including black hole mergers, cosmic string cusps, supernovae, neutron star mergers, and black hole{neutron star mergers. A subset of GW events are expected to produce electromagnetic (EM) emission that, once detected, will provide complementary information about their astrophysical context. To that end, the LIGO-Virgo Collaboration has partnered with other teams to send GW candidate alerts so that searches for their EM counterparts can be pursued. One such partner is the Dark Energy Survey (DES) and Dark Energy Camera (DECam) Gravitational Waves Program (DES- GW). Situated on the 4m Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile, DECam is an ideal instrument for optical followup observations of GW triggers in the southern sky. The DES-GW program performs subtraction of new search images with respect to preexisting overlapping images to select candidate sources. Due to the short decay timescale of the expected EM counterparts and the need to quickly eliminate survey areas with no counterpart candidates, it is critical to complete the initial analysis of each night's images within 24 hours. The computational challenges in achieving this goal include maintaining robust I/O pipelines during the processing, being able to quickly acquire template images of new sky regions outside of the typical DES observing regions, and being able to rapidly provision additional batch computing resources with little advance notice. We will discuss the search area determination, imaging pipeline, general data transfer strategy, and methods to quickly increase the available amount of batch computing. We will present results from the rst season of observations from September 2015 to January 2016 and conclude by presenting improvements planned for the second observing season.
The dawn of gravitational wave astronomy
CERN. Geneva
2016-01-01
On Sep 14 2015, gravitational waves were for the first time detected directly. This observation by the LIGO interferometric detectors marks the dawn of a new era in our observational study of the cosmos as a qualitatively new window to its exploration has been opened. This talk reviews some of the fundamental concepts of gravitational waves and the methodology employed for their observation. The first event, dubbed GW150914, and the properties of its source, as inferred from the observation, will be discussed. The talk concludes with a selected set of the most important topics where we expect gravitational-wave observations to deepen and either challenge or confirm our present understanding of the laws and the history of our universe.
Gravitational lensing of gravitational waves: a statistical perspective
Li, Shun-Sheng; Mao, Shude; Zhao, Yuetong; Lu, Youjun
2018-05-01
In this paper, we study the strong gravitational lensing of gravitational waves (GWs) from a statistical perspective, with particular focus on the high frequency GWs from stellar binary black hole coalescences. These are most promising targets for ground-based detectors such as Advanced Laser Interferometer Gravitational Wave Observatory (aLIGO) and the proposed Einstein Telescope (ET) and can be safely treated under the geometrical optics limit for GW propagation. We perform a thorough calculation of the lensing rate, by taking account of effects caused by the ellipticity of lensing galaxies, lens environments, and magnification bias. We find that in certain GW source rate scenarios, we should be able to observe strongly lensed GW events once per year (˜1 yr-1) in the aLIGO survey at its design sensitivity; for the proposed ET survey, the rate could be as high as ˜80 yr-1. These results depend on the estimate of GW source abundance, and hence can be correspondingly modified with an improvement in our understanding of the merger rate of stellar binary black holes. We also compute the fraction of four-image lens systems in each survey, predicting it to be ˜30 per cent for the aLIGO survey and ˜6 per cent for the ET survey. Finally, we evaluate the possibility of missing some images due to the finite survey duration, by presenting the probability distribution of lensing time delays. We predict that this selection bias will be insignificant in future GW surveys, as most of the lens systems ({˜ } 90{per cent}) will have time delays less than ˜1 month, which will be far shorter than survey durations.
Yagi, Kent; Yang, Huan
2018-05-01
The recent discovery of gravitational-wave events has offered us unique test beds of gravity in the strong and dynamical field regime. One possible modification to General Relativity is the gravitational parity violation that arises naturally from quantum gravity. Such parity violation gives rise to the so-called amplitude birefringence in gravitational waves, in which one of the circularly polarized modes is amplified while the other one is suppressed during their propagation. In this paper, we study how well one can measure gravitational parity violation via the amplitude birefringence effect of gravitational waves sourced by stellar-mass black hole binaries. We choose Chern-Simons gravity as an example and work within an effective field theory formalism to ensure that the approximate theory is well posed. We consider gravitational waves from both individual sources and stochastic gravitational-wave backgrounds. Regarding bounds from individual sources, we estimate such bounds using a Fisher analysis and carry out Monte Carlo simulations by randomly distributing sources over their sky location and binary orientation. We find that the bounds on the scalar field evolution in Chern-Simons gravity from the recently discovered gravitational-wave events are too weak to satisfy the weak Chern-Simons approximation, while aLIGO with its design sensitivity can place meaningful bounds. Regarding bounds from stochastic gravitational-wave backgrounds, we set the threshold signal-to-noise ratio for detection of the parity-violation mode as 5 and estimate projected bounds with future detectors assuming that signals are consistent with no parity violation. In an ideal situation in which all the source parameters and binary black hole merger-rate history are known a priori, we find that a network of two third-generation detectors is able to place bounds that are comparable to or slightly stronger than binary pulsar bounds. In a more realistic situation in which one does not have
GLINT. Gravitational-wave laser INterferometry triangle
Aria, Shafa; Azevedo, Rui; Burow, Rick; Cahill, Fiachra; Ducheckova, Lada; Holroyd, Alexa; Huarcaya, Victor; Järvelä, Emilia; Koßagk, Martin; Moeckel, Chris; Rodriguez, Ana; Royer, Fabien; Sypniewski, Richard; Vittori, Edoardo; Yttergren, Madeleine
2017-11-01
When the universe was roughly one billion years old, supermassive black holes (103-106 solar masses) already existed. The occurrence of supermassive black holes on such short time scales are poorly understood in terms of their physical or evolutionary processes. Our current understanding is limited by the lack of observational data due the limits of electromagnetic radiation. Gravitational waves as predicted by the theory of general relativity have provided us with the means to probe deeper into the history of the universe. During the ESA Alpach Summer School of 2015, a group of science and engineering students devised GLINT (Gravitational-wave Laser INterferometry Triangle), a space mission concept capable of measuring gravitational waves emitted by black holes that have formed at the early periods after the big bang. Morespecifically at redshifts of 15 big bang) in the frequency range 0.01 - 1 Hz. GLINT design strain sensitivity of 5× 10^{-24} 1/√ { {Hz}} will theoretically allow the study of early black holes formations as well as merging events and collapses. The laser interferometry, the technology used for measuring gravitational waves, monitors the separation of test masses in free-fall, where a change of separation indicates the passage of a gravitational wave. The test masses will be shielded from disturbing forces in a constellation of three geocentric orbiting satellites.
Gravitational waves from primordial black hole mergers
Energy Technology Data Exchange (ETDEWEB)
Raidal, Martti; Vaskonen, Ville; Veermäe, Hardi, E-mail: martti.raidal@cern.ch, E-mail: ville.vaskonen@kbfi.ee, E-mail: hardi.veermae@cern.ch [NICPB, Rävala 10, 10143 Tallinn (Estonia)
2017-09-01
We study the production of primordial black hole (PBH) binaries and the resulting merger rate, accounting for an extended PBH mass function and the possibility of a clustered spatial distribution. Under the hypothesis that the gravitational wave events observed by LIGO were caused by PBH mergers, we show that it is possible to satisfy all present constraints on the PBH abundance, and find the viable parameter range for the lognormal PBH mass function. The non-observation of a gravitational wave background allows us to derive constraints on the fraction of dark matter in PBHs, which are stronger than any other current constraint in the PBH mass range 0.5−30 M {sub ⊙}. We show that the predicted gravitational wave background can be observed by the coming runs of LIGO, and its non-observation would indicate that the observed events are not of primordial origin. As the PBH mergers convert matter into radiation, they may have interesting cosmological implications, for example in the context of relieving the tension between high and low redshift measurements of the Hubble constant. However, we find that these effects are suppressed as, after recombination, no more that 1% of dark matter can be converted into gravitational waves.
Gravitational waves and antennas
CERN. Geneva
2003-01-01
Gravitational waves and their detection represent today a hot topic, which promises to play a central role in astrophysics, cosmology and theoretical physics. Technological developments have enabled the construction of such sensitive detectors that the detection of gravitational radiation and the start of a new astronomy could become a reality during the next few years. This is expected to bring a revolution in our knowledge of the universe by allowing the observation of hiterto unseen phenomena such as coalescence of compact objects (neutron stars and black holes) fall of stars into supermassive black holes, stellar core collapses, big bang relics and the new and unexpected. In these lectures I give a brief overview of this challenging field of modern physics. Topics : Basic properties of gravitational radiation. Astrophysical sources. Principle of operation of detectors. Interferometers (both ground based and space-based), bars and spheres. Present status of the experiments, their recent results and their f...
Ohanian, Hans C
2013-01-01
The third edition of this classic textbook is a quantitative introduction for advanced undergraduates and graduate students. It gently guides students from Newton's gravitational theory to special relativity, and then to the relativistic theory of gravitation. General relativity is approached from several perspectives: as a theory constructed by analogy with Maxwell's electrodynamics, as a relativistic generalization of Newton's theory, and as a theory of curved spacetime. The authors provide a concise overview of the important concepts and formulas, coupled with the experimental results underpinning the latest research in the field. Numerous exercises in Newtonian gravitational theory and Maxwell's equations help students master essential concepts for advanced work in general relativity, while detailed spacetime diagrams encourage them to think in terms of four-dimensional geometry. Featuring comprehensive reviews of recent experimental and observational data, the text concludes with chapters on cosmology an...
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.
Supersymmetry and gravitational duality
International Nuclear Information System (INIS)
Argurio, Riccardo; Dehouck, Francois; Houart, Laurent
2009-01-01
We study how the supersymmetry algebra copes with gravitational duality. As a playground, we consider a charged Taub-Newman-Unti-Tamburino(NUT) solution of D=4, N=2 supergravity. We find explicitly its Killing spinors, and the projection they obey provides evidence that the dual magnetic momenta necessarily have to appear in the supersymmetry algebra. The existence of such a modification is further supported using an approach based on the Nester form. In the process, we find new expressions for the dual magnetic momenta, including the NUT charge. The same expressions are then rederived using gravitational duality.
Collaboration 'Engineerability'
Kolfschoten, Gwendolyn L.; de Vreede, Gert-Jan; Briggs, Robert O.; Sol, Henk G.
Collaboration Engineering is an approach to create sustained collaboration support by designing collaborative work practices for high-value recurring tasks, and transferring those designs to practitioners to execute for themselves without ongoing support from collaboration professionals. A key
Einstein-Rosen gravitational waves
International Nuclear Information System (INIS)
Astefanoaei, Iordana; Maftei, Gh.
2001-01-01
In this paper we analyse the behaviour of the gravitational waves in the approximation of the far matter fields, considering the indirect interaction between the matter sources and the gravitational field, in a cosmological model based on the Einstein-Rosen solution, Because the properties of the gravitational waves obtained as the solutions of Einstein fields equations (the gravitational field equations) are most obvious in the weak gravitational fields we consider here, the gravitational field in the linear approximation. Using the Newman-Penrose formalism, we calculate in the null-tetradic base (e a ), the spin coefficients, the directional derivates and the tetradic components of Ricci and Weyl tensors. From the Einstein field equations we obtained the solution for b(z, t) what described the behaviour of gravitational wave in Einstein-Rosen Universe and in the particular case, when t → ∞, p(z, t) leads us to the primordial gravitational waves in the Einstein-Rosen Universe. (authors)
Gravitational lenses and cosmological evolution
International Nuclear Information System (INIS)
Peacock, J.A.
1982-01-01
The effect of gravitational lensing on the apparent cosmological evolution of extragalactic radio sources is investigated. Models for a lens population consisting of galaxies and clusters of galaxies are constructed and used to calculate the distribution of amplification factors caused by lensing. Although many objects at high redshifts are predicted to have flux densities altered by 10 to 20 per cent relative to a homogeneous universe, flux conservation implies that de-amplification is as common as amplification. The effects on cosmological evolution as inferred from source counts and redshift data are thus relatively small; the slope of the counts is not large enough for intrinsically rare lensing events of high amplitude to corrupt observed samples. Lensing effects may be of greater importance for optically selected quasars, where lenses of mass as low as approximately 10 -4 solar mass can cause large amplifications. (author)
Difference Image Analysis of Galactic Microlensing. II. Microlensing Events
Energy Technology Data Exchange (ETDEWEB)
Alcock, C.; Allsman, R. A.; Alves, D.; Axelrod, T. S.; Becker, A. C.; Bennett, D. P.; Cook, K. H.; Drake, A. J.; Freeman, K. C.; Griest, K. (and others)
1999-09-01
The MACHO collaboration has been carrying out difference image analysis (DIA) since 1996 with the aim of increasing the sensitivity to the detection of gravitational microlensing. This is a preliminary report on the application of DIA to galactic bulge images in one field. We show how the DIA technique significantly increases the number of detected lensing events, by removing the positional dependence of traditional photometry schemes and lowering the microlensing event detection threshold. This technique, unlike PSF photometry, gives the unblended colors and positions of the microlensing source stars. We present a set of criteria for selecting microlensing events from objects discovered with this technique. The 16 pixel and classical microlensing events discovered with the DIA technique are presented. (c) (c) 1999. The American Astronomical Society.
Experiment to measure the gravitational force on the antiproton
International Nuclear Information System (INIS)
Brown, R.E.
1985-01-01
A collaboration has been formed to measure the acceleration of antiprotons in the earth's gravitational field. The technique is to produce, decelerate, and trap quantities of antiprotons, to cool them to untralow energy, and to measure their acceleration in a time-of-flight experiment. Present plans and the results of initial efforts toward this end are presented
Gravitation radiation observations
Glass, E. N.
2017-01-01
The notion of gravitational radiation begins with electromagnetic radiation. In 1887 Heinrich Hertz, working in one room, generated and received electromagnetic radiation. Maxwell's equations describe the electromagnetic field. The quanta of electromagnetic radiation are spin 1 photons. They are fundamental to atomic physics and quantum electrodynamics.
Alternative equations of gravitation
International Nuclear Information System (INIS)
Pinto Neto, N.
1983-01-01
It is shown, trough a new formalism, that the quantum fluctuation effects of the gravitational field in Einstein's equations are analogs to the effects of a continuum medium in Maxwell's Electrodynamics. Following, a real example of the applications of these equations is studied. Qunatum fluctuations effects as perturbation sources in Minkowski and Friedmann Universes are examined. (L.C.) [pt
Glitches and gravitational waves
Indian Academy of Sciences (India)
A M Srivastava
2017-10-09
Oct 9, 2017 ... We also discuss gravitational wave production due to rapidly changing ... efficient source of energy loss during the cooling of the neutron star. ..... [3] U S Gupta, R K Mohapatra, A M Srivastava and V K. Tiwari, Phys. Rev. D 82 ...
Extragalactic Gravitational Collapse
Rees, Martin J.
After some introductory "numerology", routes towards black hole formation are briefly reviewed; some properties of black holes relevant to theories for active galactic nuclei are then described. Applications are considered to specific models for energy generation and the production of relativistic beams. The paper concludes with a discussion of extragalactic sources of gravitational waves.
Indian Academy of Sciences (India)
Keywords. General relativity; gravitational waves; astrophysics; interferometry. Author Affiliations. P Ajith1 K G Arun2. LIGO Laboratory and Theoretical Astrophysics California Institute of Technology MS 18-34, Pasadena CA 91125, USA. Chennai Mathematical Institute Plot H1, SIPCOT IT Park Siruseri, Padur Post Chennai ...
International Nuclear Information System (INIS)
Kikkawa, Keiji; Nakanishi, Noboru; Nariai, Hidekazu
1983-01-01
These proceedings contain the articles presented at the named symposium. They deal with geometrical aspects of gauge theory and gravitation, special problems in gauge theories, quantum field theory in curved space-time, quantum gravity, supersymmetry including supergravity, and grand unification. See hints under the relevant topics. (HSI)
Gravitational-wave astronomy: delivering on the promises
Schutz, B. F.
2018-05-01
Now that LIGO and Virgo have begun to detect gravitational-wave events with regularity, the field of gravitational-wave astronomy is beginning to realize its promise. Binary black holes and, very recently, binary neutron stars have been observed, and we are already learning much from them. The future, with improved sensitivity, more detectors and detectors like LISA in different frequency bands, has even more promise to open a completely hidden side of the Universe to our exploration. This article is part of a discussion meeting issue `The promises of gravitational-wave astronomy'.
Gravitational collapse of charged dust shell and maximal slicing condition
International Nuclear Information System (INIS)
Maeda, Keiichi
1980-01-01
The maximal slicing condition is a good time coordinate condition qualitatively when pursuing the gravitational collapse by the numerical calculation. The analytic solution of the gravitational collapse under the maximal slicing condition is given in the case of a spherical charged dust shell and the behavior of time slices with this coordinate condition is investigated. It is concluded that under the maximal slicing condition we can pursue the gravitational collapse until the radius of the shell decreases to about 0.7 x (the radius of the event horizon). (author)
Gravitational-wave astronomy: delivering on the promises.
Schutz, B F
2018-05-28
Now that LIGO and Virgo have begun to detect gravitational-wave events with regularity, the field of gravitational-wave astronomy is beginning to realize its promise. Binary black holes and, very recently, binary neutron stars have been observed, and we are already learning much from them. The future, with improved sensitivity, more detectors and detectors like LISA in different frequency bands, has even more promise to open a completely hidden side of the Universe to our exploration.This article is part of a discussion meeting issue 'The promises of gravitational-wave astronomy'. © 2018 The Author(s).
On constraining the speed of gravitational waves following GW150914
Blas, Diego; Sawicki, Ignacy; Sibiryakov, Sergey
2016-07-31
We point out that the observed time delay between the detection of the signal at the Hanford and Livingston LIGO sites from the gravitational wave event GW150914 places an upper bound on the speed of propagation of gravitational waves, $c_{gw}\\lesssim 1.7$ in the units of speed of light. Combined with the lower bound from the absence of gravitational Cherenkov losses by cosmic rays that rules out most of subluminal velocities, this gives a model-independent double-sided constraint $1\\lesssim c_{gw}\\lesssim 1.7$. We compare this result to model-specific constraints from pulsar timing and cosmology.
Gravitational waves from a pulsar kick caused by neutrino conversions
International Nuclear Information System (INIS)
Loveridge, Lee C.
2004-01-01
It has been suggested that the observed pulsar velocities are caused by an asymmetric neutrino emission from a hot neutron star during the first seconds after the supernova collapse. We calculate the magnitude of gravitational waves produced by the asymmetries in the emission of neutrinos. The resulting periodic gravitational waves may be detectable by LIGO and LISA in the event of a nearby supernova explosion
Maximilien Brice
2005-01-01
Based on the collaboration-fostering and research-enabling role of the grid, CERN and UNESCO are taking the opportunity to invite current and future grid participants, universities and research institutions to a grid event hosted by CERN in Geneva. Through presentations by key grid protagonists from CERN, the European Commission, the EGEE Grid, and the European research community, participants have been able to learn about the capabilities of the grid, opportunities to leverage their research work, and participation in international projects.
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Ormiston, R; Ortega, L F; O'Shaughnessy, R; Ossokine, S; Ottaway, D J; Overmier, H; Owen, B J; Pace, A E; Page, J; Page, M A; Pai, A; Pai, S A; Palamos, J R; Palashov, O; Palomba, C; Pal-Singh, A; Pan, Howard; Pan, Huang-Wei; Pang, B; Pang, P T H; Pankow, C; Pannarale, F; Pant, B C; Paoletti, F; Paoli, A; Papa, M A; Parida, A; Parker, W; Pascucci, D; Pasqualetti, A; Passaquieti, R; Passuello, D; Patil, M; Patricelli, B; Pearlstone, B L; Pedraza, M; Pedurand, R; Pekowsky, L; Pele, A; Penn, S; Perez, C J; Perreca, A; Perri, L M; Pfeiffer, H P; Phelps, M; Piccinni, O J; Pichot, M; Piergiovanni, F; Pierro, V; Pillant, G; Pinard, L; Pinto, I M; Pirello, M; Pitkin, M; Poe, M; Poggiani, R; Popolizio, P; Porter, E K; Post, A; Powell, J; Prasad, J; Pratt, J W W; Pratten, G; Predoi, V; Prestegard, T; Prijatelj, M; Principe, M; Privitera, S; Prodi, G A; Prokhorov, L G; Puncken, O; Punturo, M; Puppo, P; Pürrer, M; Qi, H; Quetschke, V; Quintero, E A; Quitzow-James, R; Raab, F J; Rabeling, D S; Radkins, H; Raffai, P; Raja, S; Rajan, C; Rajbhandari, B; Rakhmanov, M; Ramirez, K E; Ramos-Buades, A; Rapagnani, P; Raymond, V; Razzano, M; Read, J; Regimbau, T; Rei, L; Reid, S; Reitze, D H; Ren, W; Reyes, S D; Ricci, F; Ricker, P M; Rieger, S; Riles, K; Rizzo, M; Robertson, N A; Robie, R; Robinet, F; Rocchi, A; Rolland, L; Rollins, J G; Roma, V J; Romano, J D; Romano, R; Romel, C L; Romie, J H; Rosińska, D; Ross, M P; Rowan, S; Rüdiger, A; Ruggi, P; Rutins, G; Ryan, K; Sachdev, S; Sadecki, T; Sadeghian, L; Sakellariadou, M; Salconi, L; Saleem, M; Salemi, F; Samajdar, A; Sammut, L; Sampson, L M; Sanchez, E J; Sanchez, L E; Sanchis-Gual, N; Sandberg, V; Sanders, J R; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Sauter, O; Savage, R L; Sawadsky, A; Schale, P; Scheel, M; Scheuer, J; Schmidt, J; Schmidt, P; Schnabel, R; Schofield, R M S; Schönbeck, A; Schreiber, E; Schuette, D; Schulte, B W; Schutz, B F; Schwalbe, S G; Scott, J; Scott, S M; Seidel, E; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Shaddock, D A; Shaffer, T J; Shah, A A; Shahriar, M S; Shaner, M B; Shao, L; Shapiro, B; Shawhan, P; Sheperd, A; Shoemaker, D H; Shoemaker, D M; Siellez, K; Siemens, X; Sieniawska, M; Sigg, D; Silva, A D; Singer, L P; Singh, A; Singhal, A; Sintes, A M; Slagmolen, B J J; Smith, B; Smith, J R; Smith, R J E; Somala, S; Son, E J; Sonnenberg, J A; Sorazu, B; Sorrentino, F; Souradeep, T; Spencer, A P; Srivastava, A K; Staats, K; Staley, A; Steinke, M; Steinlechner, J; Steinlechner, S; Steinmeyer, D; Stevenson, S P; Stone, R; Stops, D J; Strain, K A; Stratta, G; Strigin, S E; Strunk, A; Sturani, R; Stuver, A L; Summerscales, T Z; Sun, L; Sunil, S; Suresh, J; Sutton, P J; Swinkels, B L; Szczepańczyk, M J; Tacca, M; Tait, S C; Talbot, C; Talukder, D; Tanner, D B; Tápai, M; Taracchini, A; Tasson, J D; Taylor, J A; Taylor, R; Tewari, S V; Theeg, T; Thies, F; Thomas, E G; Thomas, M; Thomas, P; Thorne, K A; Thrane, E; Tiwari, S; Tiwari, V; Tokmakov, K V; Toland, K; Tonelli, M; Tornasi, Z; Torres-Forné, A; Torrie, C I; Töyrä, D; Travasso, F; Traylor, G; Trinastic, J; Tringali, M C; Trozzo, L; Tsang, K W; Tse, M; Tso, R; Tsukada, L; Tsuna, D; Tuyenbayev, D; Ueno, K; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; van Bakel, N; van Beuzekom, M; van den Brand, J F J; Van Den Broeck, C; Vander-Hyde, D C; van der Schaaf, L; van Heijningen, J V; van Veggel, A A; Vardaro, M; Varma, V; Vass, S; Vasúth, M; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Venugopalan, G; Verkindt, D; Vetrano, F; Viceré, A; Viets, A D; Vinciguerra, S; Vine, D J; Vinet, J-Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Vyatchanin, S P; Wade, A R; Wade, L E; Wade, M; Walet, R; Walker, M; Wallace, L; Walsh, S; Wang, G; Wang, H; Wang, J Z; Wang, W H; Wang, Y F; Ward, R L; Warner, J; Was, M; Watchi, J; Weaver, B; Wei, L-W; Weinert, M; Weinstein, A J; Weiss, R; Wen, L; Wessel, E K; Weßels, P; Westerweck, J; Westphal, T; Wette, K; Whelan, J T; Whiting, B F; Whittle, C; Wilken, D; Williams, D; Williams, R D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M H; Winkler, W; Wipf, C C; Wittel, H; Woan, G; Woehler, J; Wofford, J; Wong, K W K; Worden, J; Wright, J L; Wu, D S; Wysocki, D M; Xiao, S; Yamamoto, H; Yancey, C C; Yang, L; Yap, M J; Yazback, M; Yu, Hang; Yu, Haocun; Yvert, M; Zadrożny, A; Zanolin, M; Zelenova, T; Zendri, J-P; Zevin, M; Zhang, L; Zhang, M; Zhang, T; Zhang, Y-H; Zhao, C; Zhou, M; Zhou, Z; Zhu, S J; Zhu, X J; Zucker, M E; Zweizig, J
2018-03-02
The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude Ω_{GW}(f=25 Hz)=1.8_{-1.3}^{+2.7}×10^{-9} with 90% confidence, compared with Ω_{GW}(f=25 Hz)=1.1_{-0.7}^{+1.2}×10^{-9} from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.
Abbott, B. P.; Abbott, R.; Abbott, T. D.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Afrough, M.; Agarwal, B.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allen, G.; Allocca, A.; Altin, P. A.; Amato, A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Angelova, S. V.; Antier, S.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Atallah, D. V.; Aufmuth, P.; Aulbert, C.; AultONeal, K.; Austin, C.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Bae, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Banagiri, S.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barkett, K.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bawaj, M.; Bayley, J. C.; Bazzan, M.; Bécsy, B.; Beer, C.; Bejger, M.; Belahcene, I.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Bero, J. J.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Biscoveanu, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A.; Blackburn, J. K.; Blackman, J.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, S.; Bock, O.; Bode, N.; Boer, M.; Bogaert, G.; Bohe, A.; Bondu, F.; Bonilla, E.; Bonnand, R.; Boom, B. A.; Bork, R.; Boschi, V.; Bose, S.; Bossie, K.; Bouffanais, Y.; Bozzi, A.; Bradaschia, C.; Brady, P. R.; Branchesi, M.; Brau, J. E.; Briant, T.; Brillet, A.; Brinkmann, M.; Brisson, V.; Brockill, P.; Broida, J. E.; Brooks, A. F.; Brown, D. A.; Brown, D. D.; Brunett, S.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. 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L.; Doravari, S.; Dorrington, I.; Douglas, R.; Dovale Álvarez, M.; Downes, T. P.; Drago, M.; Dreissigacker, C.; Driggers, J. C.; Du, Z.; Ducrot, M.; Dupej, P.; Dwyer, S. E.; Edo, T. B.; Edwards, M. C.; Effler, A.; Eggenstein, H.-B.; Ehrens, P.; Eichholz, J.; Eikenberry, S. S.; Eisenstein, R. A.; Essick, R. C.; Estevez, D.; Etienne, Z. B.; Etzel, T.; Evans, M.; Evans, T. M.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.; Farinon, S.; Farr, B.; Farr, W. M.; Fauchon-Jones, E. J.; Favata, M.; Fays, M.; Fee, C.; Fehrmann, H.; Feicht, J.; Fejer, M. M.; Fernandez-Galiana, A.; Ferrante, I.; Ferreira, E. C.; Ferrini, F.; Fidecaro, F.; Finstad, D.; Fiori, I.; Fiorucci, D.; Fishbach, M.; Fisher, R. P.; Fitz-Axen, M.; Flaminio, R.; Fletcher, M.; Fong, H.; Font, J. A.; Forsyth, P. W. F.; Forsyth, S. S.; Fournier, J.-D.; Frasca, S.; Frasconi, F.; Frei, Z.; Freise, A.; Frey, R.; Frey, V.; Fries, E. M.; Fritschel, P.; Frolov, V. V.; Fulda, P.; Fyffe, M.; Gabbard, H.; Gadre, B. U.; Gaebel, S. M.; Gair, J. R.; Gammaitoni, L.; Ganija, M. R.; Gaonkar, S. G.; Garcia-Quiros, C.; Garufi, F.; Gateley, B.; Gaudio, S.; Gaur, G.; Gayathri, V.; Gehrels, N.; Gemme, G.; Genin, E.; Gennai, A.; George, D.; George, J.; Gergely, L.; Germain, V.; Ghonge, S.; Ghosh, Abhirup; Ghosh, Archisman; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.; Glover, L.; Goetz, E.; Goetz, R.; Gomes, S.; Goncharov, B.; González, G.; Gonzalez Castro, J. M.; Gopakumar, A.; Gorodetsky, M. L.; Gossan, S. E.; Gosselin, M.; Gouaty, R.; Grado, A.; Graef, C.; Granata, M.; Grant, A.; Gras, S.; Gray, C.; Greco, G.; Green, A. C.; Gretarsson, E. M.; Groot, P.; Grote, H.; Grunewald, S.; Gruning, P.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Halim, O.; Hall, B. R.; Hall, E. D.; Hamilton, E. Z.; Hammond, G.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hannuksela, O. A.; Hanson, J.; Hardwick, T.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Haster, C.-J.; Haughian, K.; Healy, J.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hemming, G.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hinderer, T.; Hoak, D.; Hofman, D.; Holt, K.; Holz, D. E.; Hopkins, P.; Horst, C.; Hough, J.; Houston, E. A.; Howell, E. J.; Hreibi, A.; Hu, Y. M.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Indik, N.; Inta, R.; Intini, G.; Isa, H. N.; Isac, J.-M.; Isi, M.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jiménez-Forteza, F.; Johnson, W. W.; Jones, D. I.; Jones, R.; Jonker, R. J. G.; Ju, L.; Junker, J.; Kalaghatgi, C. V.; Kalogera, V.; Kamai, B.; Kandhasamy, S.; Kang, G.; Kanner, J. B.; Kapadia, S. J.; Karki, S.; Karvinen, K. S.; Kasprzack, M.; Katolik, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kawabe, K.; Kéfélian, F.; Keitel, D.; Kemball, A. J.; Kennedy, R.; Kent, C.; Key, J. S.; Khalili, F. Y.; Khan, I.; Khan, S.; Khan, Z.; Khazanov, E. A.; Kijbunchoo, N.; Kim, Chunglee; Kim, J. C.; Kim, K.; Kim, W.; Kim, W. S.; Kim, Y.-M.; Kimbrell, S. J.; King, E. J.; King, P. J.; Kinley-Hanlon, M.; Kirchhoff, R.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Knowles, T. D.; Koch, P.; Koehlenbeck, S. M.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Krämer, C.; Kringel, V.; Krishnan, B.; Królak, A.; Kuehn, G.; Kumar, P.; Kumar, R.; Kumar, S.; Kuo, L.; Kutynia, A.; Kwang, S.; Lackey, B. D.; Lai, K. H.; Landry, M.; Lang, R. N.; Lange, J.; Lantz, B.; Lanza, R. K.; Lartaux-Vollard, A.; Lasky, P. D.; Laxen, M.; Lazzarini, A.; Lazzaro, C.; Leaci, P.; Leavey, S.; Lee, C. H.; Lee, H. K.; Lee, H. M.; Lee, H. W.; Lee, K.; Lehmann, J.; Lenon, A.; Leonardi, M.; Leroy, N.; Letendre, N.; Levin, Y.; Li, T. G. F.; Linker, S. D.; Littenberg, T. B.; Liu, J.; Lo, R. K. L.; Lockerbie, N. A.; London, L. T.; Lord, J. E.; Lorenzini, M.; Loriette, V.; Lormand, M.; Losurdo, G.; Lough, J. D.; Lousto, C. O.; Lovelace, G.; Lück, H.; Lumaca, D.; Lundgren, A. P.; Lynch, R.; Ma, Y.; Macas, R.; Macfoy, S.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magaña Hernandez, I.; Magaña-Sandoval, F.; Magaña Zertuche, L.; Magee, R. M.; Majorana, E.; Maksimovic, I.; Man, N.; Mandic, V.; Mangano, V.; Mansell, G. L.; Manske, M.; Mantovani, M.; Marchesoni, F.; Marion, F.; Márka, S.; Márka, Z.; Markakis, C.; Markosyan, A. S.; Markowitz, A.; Maros, E.; Marquina, A.; Martelli, F.; Martellini, L.; Martin, I. W.; Martin, R. M.; Martynov, D. V.; Mason, K.; Massera, E.; Masserot, A.; Massinger, T. J.; Masso-Reid, M.; Mastrogiovanni, S.; Matas, A.; Matichard, F.; Matone, L.; Mavalvala, N.; Mazumder, N.; McCarthy, R.; McClelland, D. E.; McCormick, S.; McCuller, L.; McGuire, S. C.; McIntyre, G.; McIver, J.; McManus, D. J.; McNeill, L.; McRae, T.; McWilliams, S. T.; Meacher, D.; Meadors, G. D.; Mehmet, M.; Meidam, J.; Mejuto-Villa, E.; Melatos, A.; Mendell, G.; Mercer, R. A.; Merilh, E. L.; Merzougui, M.; Meshkov, S.; Messenger, C.; Messick, C.; Metzdorff, R.; Meyers, P. M.; Miao, H.; Michel, C.; Middleton, H.; Mikhailov, E. E.; Milano, L.; Miller, A. L.; Miller, B. B.; Miller, J.; Millhouse, M.; Milovich-Goff, M. C.; Minazzoli, O.; Minenkov, Y.; Ming, J.; Mishra, C.; Mitra, S.; Mitrofanov, V. P.; Mitselmakher, G.; Mittleman, R.; Moffa, D.; Moggi, A.; Mogushi, K.; Mohan, M.; Mohapatra, S. R. P.; Montani, M.; Moore, C. J.; Moraru, D.; Moreno, G.; Morriss, S. R.; Mours, B.; Mow-Lowry, C. M.; Mueller, G.; Muir, A. W.; Mukherjee, Arunava; Mukherjee, D.; Mukherjee, S.; Mukund, N.; Mullavey, A.; Munch, J.; Muñiz, E. A.; Muratore, M.; Murray, P. G.; Napier, K.; Nardecchia, I.; Naticchioni, L.; Nayak, R. K.; Neilson, J.; Nelemans, G.; Nelson, T. J. N.; Nery, M.; Neunzert, A.; Nevin, L.; Newport, J. M.; Newton, G.; Ng, K. K. Y.; Nguyen, T. T.; Nichols, D.; Nielsen, A. B.; Nissanke, S.; Nitz, A.; Noack, A.; Nocera, F.; Nolting, D.; North, C.; Nuttall, L. K.; Oberling, J.; O'Dea, G. D.; Ogin, G. H.; Oh, J. J.; Oh, S. H.; Ohme, F.; Okada, M. A.; Oliver, M.; Oppermann, P.; Oram, Richard J.; O'Reilly, B.; Ormiston, R.; Ortega, L. F.; O'Shaughnessy, R.; Ossokine, S.; Ottaway, D. J.; Overmier, H.; Owen, B. J.; Pace, A. E.; Page, J.; Page, M. A.; Pai, A.; Pai, S. A.; Palamos, J. R.; Palashov, O.; Palomba, C.; Pal-Singh, A.; Pan, Howard; Pan, Huang-Wei; Pang, B.; Pang, P. T. H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Parida, A.; Parker, W.; Pascucci, D.; Pasqualetti, A.; Passaquieti, R.; Passuello, D.; Patil, M.; Patricelli, B.; Pearlstone, B. L.; Pedraza, M.; Pedurand, R.; Pekowsky, L.; Pele, A.; Penn, S.; Perez, C. J.; Perreca, A.; Perri, L. M.; Pfeiffer, H. P.; Phelps, M.; Piccinni, O. J.; Pichot, M.; Piergiovanni, F.; Pierro, V.; Pillant, G.; Pinard, L.; Pinto, I. M.; Pirello, M.; Pitkin, M.; Poe, M.; Poggiani, R.; Popolizio, P.; Porter, E. K.; Post, A.; Powell, J.; Prasad, J.; Pratt, J. W. W.; Pratten, G.; Predoi, V.; Prestegard, T.; Prijatelj, M.; Principe, M.; Privitera, S.; Prodi, G. A.; Prokhorov, L. G.; Puncken, O.; Punturo, M.; Puppo, P.; Pürrer, M.; Qi, H.; Quetschke, V.; Quintero, E. A.; Quitzow-James, R.; Raab, F. J.; Rabeling, D. S.; Radkins, H.; Raffai, P.; Raja, S.; Rajan, C.; Rajbhandari, B.; Rakhmanov, M.; Ramirez, K. E.; Ramos-Buades, A.; Rapagnani, P.; Raymond, V.; Razzano, M.; Read, J.; Regimbau, T.; Rei, L.; Reid, S.; Reitze, D. H.; Ren, W.; Reyes, S. D.; Ricci, F.; Ricker, P. M.; Rieger, S.; Riles, K.; Rizzo, M.; Robertson, N. A.; Robie, R.; Robinet, F.; Rocchi, A.; Rolland, L.; Rollins, J. G.; Roma, V. J.; Romano, J. D.; Romano, R.; Romel, C. L.; Romie, J. H.; Rosińska, D.; Ross, M. P.; Rowan, S.; Rüdiger, A.; Ruggi, P.; Rutins, G.; Ryan, K.; Sachdev, S.; Sadecki, T.; Sadeghian, L.; Sakellariadou, M.; Salconi, L.; Saleem, M.; Salemi, F.; Samajdar, A.; Sammut, L.; Sampson, L. M.; Sanchez, E. J.; Sanchez, L. E.; Sanchis-Gual, N.; Sandberg, V.; Sanders, J. R.; Sassolas, B.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Scheel, M.; Scheuer, J.; Schmidt, J.; Schmidt, P.; Schnabel, R.; Schofield, R. M. S.; Schönbeck, A.; Schreiber, E.; Schuette, D.; Schulte, B. W.; Schutz, B. F.; Schwalbe, S. G.; Scott, J.; Scott, S. M.; Seidel, E.; Sellers, D.; Sengupta, A. S.; Sentenac, D.; Sequino, V.; Sergeev, A.; Shaddock, D. A.; Shaffer, T. J.; Shah, A. A.; Shahriar, M. S.; Shaner, M. B.; Shao, L.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sieniawska, M.; Sigg, D.; Silva, A. D.; Singer, L. P.; Singh, A.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, B.; Smith, J. R.; Smith, R. J. E.; Somala, S.; Son, E. J.; Sonnenberg, J. A.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Spencer, A. P.; Srivastava, A. K.; Staats, K.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stevenson, S. P.; Stone, R.; Stops, D. J.; Strain, K. A.; Stratta, G.; Strigin, S. E.; Strunk, A.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sunil, S.; Suresh, J.; Sutton, P. J.; Swinkels, B. L.; Szczepańczyk, M. J.; Tacca, M.; Tait, S. C.; Talbot, C.; Talukder, D.; Tanner, D. B.; Tápai, M.; Taracchini, A.; Tasson, J. D.; Taylor, J. A.; Taylor, R.; Tewari, S. V.; Theeg, T.; Thies, F.; Thomas, E. G.; Thomas, M.; Thomas, P.; Thorne, K. A.; Thrane, E.; Tiwari, S.; Tiwari, V.; Tokmakov, K. V.; Toland, K.; Tonelli, M.; Tornasi, Z.; Torres-Forné, A.; Torrie, C. I.; Töyrä, D.; Travasso, F.; Traylor, G.; Trinastic, J.; Tringali, M. C.; Trozzo, L.; Tsang, K. W.; Tse, M.; Tso, R.; Tsukada, L.; Tsuna, D.; Tuyenbayev, D.; Ueno, K.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Usman, S. A.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; van Beuzekom, M.; van den Brand, J. F. J.; Van Den Broeck, C.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Varma, V.; Vass, S.; Vasúth, M.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P. J.; Venkateswara, K.; Venugopalan, G.; Verkindt, D.; Vetrano, F.; Viceré, A.; Viets, A. D.; Vinciguerra, S.; Vine, D. J.; Vinet, J.-Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, M.; Walet, R.; Walker, M.; Wallace, L.; Walsh, S.; Wang, G.; Wang, H.; Wang, J. Z.; Wang, W. H.; Wang, Y. F.; Ward, R. L.; Warner, J.; Was, M.; Watchi, J.; Weaver, B.; Wei, L.-W.; Weinert, M.; Weinstein, A. J.; Weiss, R.; Wen, L.; Wessel, E. K.; Weßels, P.; Westerweck, J.; Westphal, T.; Wette, K.; Whelan, J. T.; Whiting, B. F.; Whittle, C.; Wilken, D.; Williams, D.; Williams, R. D.; Williamson, A. R.; Willis, J. L.; Willke, B.; Wimmer, M. H.; Winkler, W.; Wipf, C. C.; Wittel, H.; Woan, G.; Woehler, J.; Wofford, J.; Wong, K. W. K.; Worden, J.; Wright, J. L.; Wu, D. S.; Wysocki, D. M.; Xiao, S.; Yamamoto, H.; Yancey, C. C.; Yang, L.; Yap, M. J.; Yazback, M.; Yu, Hang; Yu, Haocun; Yvert, M.; ZadroŻny, A.; Zanolin, M.; Zelenova, T.; Zendri, J.-P.; Zevin, M.; Zhang, L.; Zhang, M.; Zhang, T.; Zhang, Y.-H.; Zhao, C.; Zhou, M.; Zhou, Z.; Zhu, S. J.; Zhu, X. J.; Zucker, M. E.; Zweizig, J.; LIGO Scientific Collaboration; Virgo Collaboration
2018-03-01
The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude ΩGW(f =25 Hz )=1. 8-1.3+2.7×10-9 with 90% confidence, compared with ΩGW(f =25 Hz )=1. 1-0.7+1.2×10-9 from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.
Huffman, Jeff C; Mastromauro, Carol A; Beach, Scott R; Celano, Christopher M; DuBois, Christina M; Healy, Brian C; Suarez, Laura; Rollman, Bruce L; Januzzi, James L
2014-06-01
Depression and anxiety are associated with adverse cardiovascular outcomes in patients with recent acute cardiac events. There has been minimal study of collaborative care (CC) management models for mental health disorders in high-risk cardiac inpatients, and no prior CC intervention has simultaneously managed depression and anxiety disorders. To determine the impact of a low-intensity CC intervention for depression, generalized anxiety disorder, and panic disorder among patients hospitalized for an acute cardiac illness. Single-blind randomized clinical trial, with study assessors blind to group assignment, from September 2010 through July 2013 of 183 patients admitted to inpatient cardiac units in an urban academic general hospital for acute coronary syndrome, arrhythmia, or heart failure and found to have clinical depression, generalized anxiety disorder, or panic disorder on structured assessment. Participants were randomized to 24 weeks of a low-intensity telephone-based multicomponent CC intervention targeting depression and anxiety disorders (n = 92) or to enhanced usual care (serial notification of primary medical providers; n = 91). The CC intervention used a social work care manager to coordinate assessment and stepped care of psychiatric conditions and to provide support and therapeutic interventions as appropriate. Improvement in mental health-related quality of life (Short Form-12 Mental Component Score [SF-12 MCS]) at 24 weeks, compared between groups using a random-effects model in an intent-to-treat analysis. Patients randomized to CC had significantly greater estimated mean improvements in SF-12 MCS at 24 weeks (11.21 points [from 34.21 to 45.42] in the CC group vs 5.53 points [from 36.30 to 41.83] in the control group; estimated mean difference, 5.68 points [95% CI, 2.14-9.22]; P = .002; effect size, 0.61). Patients receiving CC also had significant improvements in depressive symptoms and general functioning, and higher rates of
DEFF Research Database (Denmark)
Mitchell, Robb
This position paper briefly outlines my interest in embarrassment– principally in relation to experiments provoking collaborative encounters in contexts that range from urban spaces to art galleries, and from music events to industrial innovation workshops.......This position paper briefly outlines my interest in embarrassment– principally in relation to experiments provoking collaborative encounters in contexts that range from urban spaces to art galleries, and from music events to industrial innovation workshops....
Projective relativity, cosmology and gravitation
International Nuclear Information System (INIS)
Arcidiacono, G.
1986-01-01
This book describes the latest applications of projective geometry to cosmology and gravitation. The contents of the book are; the Poincare group and Special Relativity, the thermodynamics and electromagnetism, general relativity, gravitation and cosmology, group theory and models of universe, the special projective relativity, the Fantappie group and Big-Bang cosmology, a new cosmological projective mechanics, the plasma physics and cosmology, the projective magnetohydrodynamics field, projective relativity and waves propagation, the generalizations of the gravitational field, the general projective relativity, the projective gravitational field, the De Sitter Universe and quantum physics, the conformal relativity and Newton gravitation
Global gravitational anomalies
International Nuclear Information System (INIS)
Witten, E.
1985-01-01
A general formula for global gauge and gravitational anomalies is derived. It is used to show that the anomaly free supergravity and superstring theories in ten dimensions are all free of global anomalies that might have ruined their consistency. However, it is shown that global anomalies lead to some restrictions on allowed compactifications of these theories. For example, in the case of O(32) superstring theory, it is shown that a global anomaly related to π 7 (O(32)) leads to a Dirac-like quantization condition for the field strength of the antisymmetric tensor field. Related to global anomalies is the question of the number of fermion zero modes in an instanton field. It is argued that the relevant gravitational instantons are exotic spheres. It is shown that the number of fermion zero modes in an instanton field is always even in ten dimensional supergravity. (orig.)
Gravitational properties of antimatter
International Nuclear Information System (INIS)
Goldman, T.; Nieto, M.M.
1985-01-01
Quantum gravity is at the forefront of modern particle physics, yet there are no direct tests, for antimatter, of even the principle of equivalence. We note that modern descriptions of gravity, such as fibre bundles and higher dimensional spacetimes, allow violations of the commonly stated form of the principle of equivalence, and of CPT. We review both indirect arguments and experimental tests of the expected gravitational properties of CPT-conjugate states. We conclude that a direct experimental test of the gravitational properties of antimatter, at the 1% (or better) level, would be of great value. We identify some experimental reasons which make the antiproton a prime candidate for this test, and we strongly urge that such an experiment be done at LEAR. 21 references
Gravitation and electromagnetism
Apsel, D
1979-01-01
Through an examination of the Bohm-Aharonov experiment, a new theory of gravitation and electromagnetism is proposed. The fundamental assumption of the theory is that the motion of a particle in a combination of gravitational and electromagnetic fields is determined from a variational principle of the form delta integral /sub A//sup B /d tau =0. The form of the physical time is determined from an examination of the Maxwell-Einstein action function. The field and motion equations are formally identical to those of Maxwell-Einstein theory. The theory predicts that even in a field-free region of space, electromagnetic potentials can alter the phase of a wave function and the lifetime of a charged particle. The phase alteration has been observed in the Bohm-Aharonov experiment. There is an indication that the lifetime alteration has shown up in a recent CERN storage ring experiment. Experimental tests are proposed. (11 refs).
Kopczyński, W.; Trautman, A.
This book is a revised translation of the Polish original "Czasoprzestrzeń i grawitacja", Warszawa (Poland), Państwowe Wydawnictwo Naukowe, 1984. Ideas about space and time are at the root of one's understanding of nature, both at the intuitive level of everyday experience and in the framework of sophisticated physical theories. These ideas have led to the development of geometry and its applications to physics. The contemporary physical theory of space and time, including its extention to the phenomena of gravitation, is Einstein's theory of relativity. The book is a short introduction to this theory. A great deal of emphasis is given to the geometrical aspects of relativity theory and its comparison with the Newtonian view of the world. There are short chapters on the origins of Einstein's theory, gravitational waves, cosmology, spinors and the Einstein-Cartan theory.
Energy Technology Data Exchange (ETDEWEB)
Goldoni, R
1980-11-22
A bimetric theory of gravitation within a Machian framework is developed on the basis of considerations which are completely divorced from Newton's theory. The theory is assumed to hold in any conceivable cosmos and possesses the Machian properties of being singular in the absence of matter and of explicitly incorporating the idea that properties of space-time are determined not only by local matter, but also by the average distribution of cosmological matter.
International Nuclear Information System (INIS)
Penrose, R.
1986-01-01
The author's definition for the mass-momentum/angular momentum surrounded by a spacelike 2-surface with S/sup 2/ topology is presented. This definition is motivated by some ideas from twistor theory in relation to linearized gravitational theory. The status of this definition is examined in relation to many examples which have been worked out. The reason for introducing a slight modification of the original definition is also presented
General Relativity and Gravitation
Ehlers, J.; Murdin, P.
2000-11-01
The General Theory of Relativity (GR), created by Albert Einstein between 1907 and 1915, is a theory both of gravitation and of spacetime structure. It is based on the assumption that matter, via its energy-momentum, interacts with the metric of spacetime, which is considered (in contrast to Newtonian physics and SPECIAL RELATIVITY) as a dynamical field having degrees of freedom of its own (GRAVI...
Fivebrane gravitational anomalies
International Nuclear Information System (INIS)
Becker, Katrin; Becker, Melanie
2000-01-01
Freed, Harvey, Minasian and Moore (FHMM) have proposed a mechanism to cancel the gravitational anomaly of the M-theory fivebrane coming from diffeomorphisms acting on the normal bundle. This procedure is based on a modification of the conventional M-theory Chern-Simons term. We apply the FHMM mechanism in the ten-dimensional type IIA theory. We then analyze the relation to the anomaly cancellation mechanism for the type IIA fivebrane proposed by Witten
Nondissipative gravitational turbulence
International Nuclear Information System (INIS)
Gurevich, A.V.; Zybin, K.P.
1988-01-01
The nonlinear stage of development of the Jeans instability in a cold nondissipative gravitating gas is considered. It is shown that for a time exceeding the Jeans time a nondissipative gravitational singularity (NGS) is formed in the vicinity of a local density maximum. The NGS is a stationary dynamic structure, the basis of which is the singularity. The density of the gas at the center of the NGS (for r → 0) tends to infinity, and the field potential and the mean velocity of the trapped gas, possess a power singularity. The turbulent state arises as the result of development of the instability in the case of an irregular initial density distribution. It is an hierarchic structure consisting of nested moving NGS of various sizes, the NGS of smaller dimensions being trapped in the field of a NGS of larger dimensions. The scaling relations for each given NGS in this case hold for both the gas density and density of smaller size trapped NGS. A brief comparison with the observational data shows that the real hierarchic structure of the Universe ranging from scales pertaining to spherical stellar clusters up to those of rich galaxy clusters is apparently a developed gravitational turbulence
Predicting gravitational lensing by stellar remnants
Harding, Alexander J.; Stefano, R. Di; Lépine, S.; Urama, J.; Pham, D.; Baker, C.
2018-03-01
Gravitational lensing provides a means to measure mass that does not rely on detecting and analysing light from the lens itself. Compact objects are ideal gravitational lenses, because they have relatively large masses and are dim. In this paper, we describe the prospects for predicting lensing events generated by the local population of compact objects, consisting of 250 neutron stars, five black holes, and ≈35 000 white dwarfs. By focusing on a population of nearby compact objects with measured proper motions and known distances from us, we can measure their masses by studying the characteristics of any lensing event they generate. Here, we concentrate on shifts in the position of a background source due to lensing by a foreground compact object. With Hubble Space Telescope, JWST, and Gaia, measurable centroid shifts caused by lensing are relatively frequent occurrences. We find that 30-50 detectable events per decade are expected for white dwarfs. Because relatively few neutron stars and black holes have measured distances and proper motions, it is more difficult to compute realistic rates for them. However, we show that at least one isolated neutron star has likely produced detectable events during the past several decades. This work is particularly relevant to the upcoming data releases by the Gaia mission and also to data that will be collected by JWST. Monitoring predicted microlensing events will not only help to determine the masses of compact objects, but will also potentially discover dim companions to these stellar remnants, including orbiting exoplanets.
Krishnan, B.; Papa, M. A.; Schutz, B. F.
2007-10-01
The 11th Gravitational Wave Data Analysis Workshop (GWDAW11) comes in the middle of the fifth science run (S5) of the LIGO detectors, after a full year of data-taking at design sensitivity. LIGO is starting to probe astrophysically plausible scenarios for the emission of detectable gravitational wave signals. In the absence of a detection, the upper limits on the strength of gravitational waves are beginning to add information to what was previously known from electromagnetic observations. One of the highlights of this workshop was the presentation by the LIGO Scientific Collaboration of a search for continuous waves from the Crab pulsar. Gravitational wave emission is constrained by the measured spindown measurements for the object: no more energy can go into gravitational waves than that which is lost by pulsar spindown. For most known pulsars this spindown upper limit on the strength of gravitational radiation is orders of magnitude higher than the upper limits that can be set with current gravitational wave observations. However for the Crab pulsar the gravitational wave observations which coherently combine about 9 months of data from the network of S5 LIGO detectors constrain the gravitational wave emission more strongly than the electromagnetic observations do. The gravitational wave upper limit also constrains the tri-axial ellipticity that this young pulsar could have supported since its crust solidified a thousand years ago. The Virgo detector is in the final stages of commissioning with several engineering runs completed. The TAMA detector's low frequency performance is being enhanced and another data run is foreseen by the end of 2007. The IGEC2 Collaboration presents results from the analysis of 131 days of data in coincidence among the three bar detectors EXPLORER, AURIGA and NAUTILUS. Studies are underway to analyze data in coincidence among bar and interferometer networks. Space-based detectors are receiving more attention, with the LISA Pathfinder
AGILE Observations of the Gravitational-wave Source GW170104
Energy Technology Data Exchange (ETDEWEB)
Verrecchia, F.; Pittori, C.; Lucarelli, F. [ASI Space Science Data Center (SSDC), via del Politecnico, I-00133 Roma (Italy); Tavani, M.; Ursi, A.; Argan, A.; Evangelista, Y.; Minervini, G.; Cardillo, M.; Piano, G. [INAF-IAPS, via del Fosso del Cavaliere 100, I-00133 Roma (Italy); Donnarumma, I. [ASI, via del Politecnico snc, I-00133 Roma (Italy); Bulgarelli, A.; Fuschino, F.; Labanti, C.; Fioretti, V. [INAF-IASF-Bologna, via Gobetti 101, I-40129 Bologna (Italy); Marisaldi, M. [Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen (Norway); Giuliani, A. [INAF-IASF Milano, via E.Bassini 15, I-20133 Milano (Italy); Longo, F. [Dipartimento di Fisica, Università di Trieste and INFN, via Valerio 2, I-34127 Trieste (Italy); Munar-Adrover, P. [Unitat de Física de les Radiacions, Departament de Física, and CERES-IEEC, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Spain); Pilia, M. [INAF, Osservatorio Astronomico di Cagliari, via della Scienza 5, I-09047 Selargius (Italy); and others
2017-10-01
The LIGO/Virgo Collaboration (LVC) detected on 2017 January 4 a significant gravitational-wave (GW) event (now named GW170104). We report in this Letter the main results obtained from the analysis of hard X-ray and gamma-ray data of the AGILE mission that repeatedly observed the GW170104 localization region (LR). At the LVC detection time T {sub 0} AGILE observed about 36% of the LR. The gamma-ray imaging detector did not reveal any significant emission in the energy range 50 MeV–30 GeV. Furthermore, no significant gamma-ray transients were detected in the LR that was repeatedly exposed over timescales of minutes, hours, and days. We also searched for transient emission using data near T {sub 0} of the omnidirectional detector MCAL operating in the energy band 0.4–100 MeV. A refined analysis of MCAL data shows the existence of a weak event (that we call “E2”) with a signal-to-noise ratio of 4.4 σ lasting about 32 ms and occurring 0.46 ± 0.05 s before T {sub 0}. A study of the MCAL background and of the false-alarm rate of E2 leads to the determination of a post-trial significance between 2.4σ and 2.7σ for a temporal coincidence with GW170104. We note that E2 has characteristics similar to those detected from the weak precursor of GRB 090510. The candidate event E2 is worth consideration for simultaneous detection by other satellites. If associated with GW170104, it shows emission in the MeV band of a short burst preceding the final coalescence by 0.46 s and involving ∼10{sup −7} of the total rest mass energy of the system.
Breaking a dark degeneracy with gravitational waves
Energy Technology Data Exchange (ETDEWEB)
Lombriser, Lucas; Taylor, Andy, E-mail: llo@roe.ac.uk, E-mail: ant@roe.ac.uk [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh, EH9 3HJ (United Kingdom)
2016-03-01
We identify a scalar-tensor model embedded in the Horndeski action whose cosmological background and linear scalar fluctuations are degenerate with the concordance cosmology. The model admits a self-accelerated background expansion at late times that is stable against perturbations with a sound speed attributed to the new field that is equal to the speed of light. While degenerate in scalar fluctuations, self-acceleration of the model implies a present cosmological tensor mode propagation at ∼<95 % of the speed of light with a damping of the wave amplitude that is ∼>5 % less efficient than in general relativity. We show that these discrepancies are endemic to self-accelerated Horndeski theories with degenerate large-scale structure and are tested with measurements of gravitational waves emitted by events at cosmological distances. Hence, gravitational-wave cosmology breaks the dark degeneracy in observations of the large-scale structure between two fundamentally different explanations of cosmic acceleration—a cosmological constant and a scalar-tensor modification of gravity. The gravitational wave event GW150914 recently detected with the aLIGO instruments and its potential association with a weak short gamma-ray burst observed with the Fermi GBM experiment may have provided this crucial measurement.
New results on the Search for Gravitational Waves
CERN. Geneva
2016-01-01
The webcast of simultaneous press conferences of the LIGO (https://www.youtube.com/user/VideosatNSF/live) and VIRGO (http://www.virgo-gw.eu/index_live.html) Collaborations from Washington and Cascina on the search for gravitational waves will be transmitted on Thursday 11 February 2016 at 16:30 in the Main Auditorium (500/1-001): It will be followed by a seminar on "New results on the Search for Gravitational Waves“ by Barry Barish (LIGO) Representatives of the LIGO, VIRGO and GEO experiments will be available for questions after the seminar.
Methodological studies on the search for Gravitational Waves and Neutrinos from Type II Supernovae
International Nuclear Information System (INIS)
Casentini, Claudio
2016-01-01
Type II SNe, also called Core-collapse SuperNovae have a neutrino (v) emission, as confirmed by SN 1987A, and are also potential sources of gravitational waves. Neutrinos and gravitational waves from these sources reach Earth almost contemporaneously and without relevant interaction with stellar matter and interstellar medium. The upcoming advanced gravitational interferometers would be sensitive enough to detect gravitational waves signals from close galactic Core-collapse SuperNovae events. Nevertheless, significant uncertainties on theoretical models of emission remain. A joint search of coincident low energy neutrinos and gravitational waves events from these sources would bring valuable information from the inner core of the collapsing star and would enhance the detection of the so-called Silent SuperNovae. Recently a project for a joint search involving gravitational wave interferometers and neutrino detectors has started. We discuss the benefits of a joint search and the status of the search project. (paper)
On gravitational wave energy in Einstein gravitational theory
International Nuclear Information System (INIS)
Folomeshkin, V.N.; Vlasov, A.A.
1978-01-01
By the example of precise wave solutions for the Einstein equations it is shown that a standard commonly adopted formulation of energy-momentum problem with pseudotensors provides us either with a zero or sign-variable values for the energy of gravitational waves. It is shown that if in the Einstein gravitational theory a strict transition to the limits of weak fields is realised then the theory gives us an unambiguous zero result for weak gravitational waves. The well-known non-zero result arises due to incorrect transition to weak field approximation in the Einstein gravitation theory
Gravitational wave memory in an expanding universe
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.
Gravitational Wave Detection in the Introductory Lab
Burko, Lior M.
2017-05-01
A long time ago in a galaxy far, far away, two black holes, one of mass 36 solar masses and the other of mass 29 solar masses, were dancing their death waltz, leading to their coalescence and the emission of gravitational waves carrying away with them three solar masses of energy. More precisely, it happened 1.3 billion years ago at a distance of 410 Mpc. When the waves were emitted, the most complex life forms on Earth were eukaryotes. As the gravitational waves propagated toward Earth, it changed much. Five hundred million years after the waves were emitted, or 800 million years ago, the first multicellular life forms emerged on Earth. Earth saw the Cambrian explosion 500 million years ago. Sixty-six million years ago the Cretaceous-Paleogene extinction event caused the disappearance of the dinosaurs. The first modern humans appeared 250,000 years ago.
Comparison of advanced gravitational-wave detectors
International Nuclear Information System (INIS)
Harry, Gregory M.; Houser, Janet L.; Strain, Kenneth A.
2002-01-01
We compare two advanced designs for gravitational-wave antennas in terms of their ability to detect two possible gravitational wave sources. Spherical, resonant mass antennas and interferometers incorporating resonant sideband extraction (RSE) were modeled using experimentally measurable parameters. The signal-to-noise ratio of each detector for a binary neutron star system and a rapidly rotating stellar core were calculated. For a range of plausible parameters we found that the advanced LIGO interferometer incorporating RSE gave higher signal-to-noise ratios than a spherical detector resonant at the same frequency for both sources. Spheres were found to be sensitive to these sources at distances beyond our galaxy. Interferometers were sensitive to these sources at far enough distances that several events per year would be expected
The potential for very high-frequency gravitational wave detection
International Nuclear Information System (INIS)
Cruise, A M
2012-01-01
The science case for observing gravitational waves at frequencies in the millihertz-kilohertz range using LIGO, VIRGO, GEO600 or LISA is very strong and the first results are expected at these frequencies. However, as gravitational wave astronomy progresses beyond the first detections, other frequency bands may be worth exploring. Early predictions of gravitational wave emission from discrete sources at very much higher frequencies (megahertz and above) have been published and more recent studies of cosmological signals from inflation, Kaluza-Klein modes from gravitational interactions in brane worlds and plasma instabilities surrounding violent astrophysical events, are all possible sources. This communication examines current observational possibilities and the detector technology required to make meaningful observations at these frequencies. (paper)
Upper limits on gravitational-wave bursts radiated from stellar-core collapses in our galaxy
International Nuclear Information System (INIS)
Ando, Masaki; Akutsu, Tomomi; Akutsu, Tomotada
2005-01-01
We present the results of observations with the TAMA300 gravitational-wave detector, targeting burst signals from stellar-core collapse events. We used an excess-power filter to extract gravitational-wave candidates, and developed two methods to reduce fake events caused by non-stationary noises of the detector. These analysis methods were applied to real data from the TAMA300 interferometric gravitational wave detector. We compared the data-processed results with those of a Monte Carlo simulation with an assumed galactic-event distribution model and with burst waveforms expected from numerical simulations of stellar-core collapses, in order to interpret the event candidates from an astronomical viewpoint. We set an upper limit of 5.0 x 10 3 events s -1 on the burst gravitational-wave event rate in our galaxy with a confidence level of 90%
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.
Probing Positron Gravitation at HERA
International Nuclear Information System (INIS)
Gharibyan, Vahagn
2015-07-01
An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Here I develop a method based on high energy Compton scattering to measure the gravitational interaction of accelerated charged particles. Within that formalism the Compton spectra measured at HERA rule out the positron's anti-gravity and hint for a positron's 1.3(0.2)% weaker coupling to the gravitational field relative to an electron.
Probing Positron Gravitation at HERA
Energy Technology Data Exchange (ETDEWEB)
Gharibyan, Vahagn
2015-07-15
An equality of particle and antiparticle gravitational interactions holds in general relativity and is supported by indirect observations. Here I develop a method based on high energy Compton scattering to measure the gravitational interaction of accelerated charged particles. Within that formalism the Compton spectra measured at HERA rule out the positron's anti-gravity and hint for a positron's 1.3(0.2)% weaker coupling to the gravitational field relative to an electron.
Observation results by the TAMA300 detector on gravitational wave bursts from stellar-core collapses
International Nuclear Information System (INIS)
Ando, Masaki; Aso, Youichi; Iida, Yukiyoshi; Nishi, Yuhiko; Otsuka, Shigemi; Seki, Hidetsugu; Soida, Kenji; Taniguchi, Shinsuke; Tochikubo, Kuniharu; Tsubono, Kimio; Yoda, Tatsuo; Arai, Koji; Beyersdorf, Peter; Kawamura, Seiji; Sato, Shuichi; Takahashi, Ryutaro; Tatsumi, Daisuke; Tsunesada, Yoshiki; Zhu, Zong-Hong; Fujimoto, Masa-Katsu
2005-01-01
We present data-analysis schemes and results of observations with the TAMA300 gravitational wave detector, targeting burst signals from stellar-core collapse events. In analyses for burst gravitational waves, the detection and fake-reduction schemes are different from well-investigated ones for a chirp wave analysis, because precise waveform templates are not available. We used an excess -power filter for the extraction of gravitational wave candidates, and developed two methods for the reduction of fake events caused by nonstationary noises of the detector. These analysis schemes were applied to real data from the TAMA300 interferometric gravitational wave detector. As a result, fake events were reduced by a factor of about 1000 in the best cases. In addition, in order to interpret the event candidates from an astronomical viewpoint, we performed a Monte-Carlo simulation with an assumed Galactic event distribution model and with burst waveforms obtained from numerical simulations of stellar-core collapses. We set an upper limit of 5.0x10 3 events/sec on the burst gravitational wave event rate in our Galaxy with a confidence level of 90%. This work shows prospects on the search for burst gravitational waves, by establishing an analysis scheme for the observation data from an interferometric gravitational wave detector
Source modelling at the dawn of gravitational-wave astronomy
Gerosa, Davide
2016-09-01
The age of gravitational-wave astronomy has begun. Gravitational waves are propagating spacetime perturbations ("ripples in the fabric of space-time") predicted by Einstein's theory of General Relativity. These signals propagate at the speed of light and are generated by powerful astrophysical events, such as the merger of two black holes and supernova explosions. The first detection of gravitational waves was performed in 2015 with the LIGO interferometers. This constitutes a tremendous breakthrough in fundamental physics and astronomy: it is not only the first direct detection of such elusive signals, but also the first irrefutable observation of a black-hole binary system. The future of gravitational-wave astronomy is bright and loud: the LIGO experiments will soon be joined by a network of ground-based interferometers; the space mission eLISA has now been fully approved by the European Space Agency with a proof-of-concept mission called LISA Pathfinder launched in 2015. Gravitational-wave observations will provide unprecedented tests of gravity as well as a qualitatively new window on the Universe. Careful theoretical modelling of the astrophysical sources of gravitational-waves is crucial to maximize the scientific outcome of the detectors. In this Thesis, we present several advances on gravitational-wave source modelling, studying in particular: (i) the precessional dynamics of spinning black-hole binaries; (ii) the astrophysical consequences of black-hole recoils; and (iii) the formation of compact objects in the framework of scalar-tensor theories of gravity. All these phenomena are deeply characterized by a continuous interplay between General Relativity and astrophysics: despite being a truly relativistic messenger, gravitational waves encode details of the astrophysical formation and evolution processes of their sources. We work out signatures and predictions to extract such information from current and future observations. At the dawn of a revolutionary
Quantum phenomena in gravitational field
Bourdel, Th.; Doser, M.; Ernest, A. D.; Voronin, A. Yu.; Voronin, V. V.
2011-10-01
The subjects presented here are very different. Their common feature is that they all involve quantum phenomena in a gravitational field: gravitational quantum states of ultracold antihydrogen above a material surface and measuring a gravitational interaction of antihydrogen in AEGIS, a quantum trampoline for ultracold atoms, and a hypothesis on naturally occurring gravitational quantum states, an Eötvös-type experiment with cold neutrons and others. Considering them together, however, we could learn that they have many common points both in physics and in methodology.
Quantum phenomena in gravitational field
International Nuclear Information System (INIS)
Bourdel, Th.; Doser, M.; Ernest, A.D.; Voronin, A.Y.; Voronin, V.V.
2010-01-01
The subjects presented here are very different. Their common feature is that they all involve quantum phenomena in a gravitational field: gravitational quantum states of ultracold anti-hydrogen above a material surface and measuring a gravitational interaction of anti-hydrogen in AEGIS, a quantum trampoline for ultracold atoms, and a hypothesis on naturally occurring gravitational quantum states, an Eoetvoes-type experiment with cold neutrons and others. Considering them together, however, we could learn that they have many common points both in physics and in methodology. (authors)
Gravitational radiation from dust
International Nuclear Information System (INIS)
Isaacson, R.A.; Welling, J.S.; Winicour, J.
1985-01-01
A dust cloud is examined within the framework of the general relativistic characteristic initial value problem. Unique gravitational initial data are obtained by requiring that the space-time be quasi-Newtonian. Explicit calculations of metric and matter fields are presented, which include all post-Newtonian corrections necessary to discuss the major physical properties of null infinity. These results establish a curved space version of the Einstein quadrupole formula, in the form ''news function equals third time derivative of transverse quadrupole moment,'' for this system. However, these results imply that some weakened notion of asymptotic flatness is necessary for the description of quasi-Newtonian systems
The earth's gravitational field
Digital Repository Service at National Institute of Oceanography (India)
Ramprasad, T.
. But to say that gravity acts downwards is not correct. Gravity acts down, no matter where you stand on the Earth. It is better to say that on Earth gravity pulls objects towards the centre of the Earth. So no matter where you are on Earth all objects fall... pull than objects at the poles. In combination, the equatorial bulge and the effects of centrifugal force mean that sea-level gravitational acceleration increases from about 9.780 m/s² at the equator to about 9.832 m/s² at the poles, so an object...
Superstatistics and Gravitation
Directory of Open Access Journals (Sweden)
Octavio Obregón
2010-09-01
Full Text Available We suggest to consider the spacetime as a non-equilibrium system with a long-term stationary state that possess as a spatio-temporally fluctuating quantity ß . These systems can be described by a superposition of several statistics, superstatistics. We propose a Gamma distribution for f(ß that depends on a parameter ρ1. By means of it the corresponding entropy is calculated, ρ1 is identified with the probability corresponding to this model. A generalized Newton’s law of gravitation is then obtained following the entropic force formulation. We discuss some of the difficulties to try to get an associated theory of gravity.
Detecting stochastic backgrounds of gravitational waves with pulsar timing arrays
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.
A comparison of methods for gravitational wave burst searches from LIGO and Virgo
International Nuclear Information System (INIS)
Beauville, F; Buskulic, D; Grosjean, D; Bizouard, M-A; Cavalier, F; Clapson, A-C; Hello, P; Blackburn, L; Katsavounidis, E; Bosi, L; Brocco, L; Brown, D A; Chatterji, S; Christensen, N; Knight, M; Fairhurst, S; Guidi, G; Heng, S; Hewitson, M; Klimenko, S
2008-01-01
The search procedure for burst gravitational waves has been studied using 24 h of simulated data in a network of three interferometers (Hanford 4 km, Livingston 4 km and Virgo 3 km are the example interferometers). Several methods to detect burst events developed in the LIGO Scientific Collaboration (LSC) and Virgo Collaboration have been studied and compared. We have performed coincidence analysis of the triggers obtained in the different interferometers with and without simulated signals added to the data. The benefits of having multiple interferometers of similar sensitivity are demonstrated by comparing the detection performance of the joint coincidence analysis with LSC and Virgo only burst searches. Adding Virgo to the LIGO detector network can increase by 50% the detection efficiency for this search. Another advantage of a joint LIGO-Virgo network is the ability to reconstruct the source sky position. The reconstruction accuracy depends on the timing measurement accuracy of the events in each interferometer, and is displayed in this paper with a fixed source position example
International Nuclear Information System (INIS)
Leaci, Paola
2015-01-01
Semicoherent all-sky searches over year-long observation times for continuous gravitational wave signals produce various thousands of potential periodic source candidates. Efficient methods able to discard false candidate events are crucial in order to put all the efforts into a computationally intensive follow-up analysis for the remaining most promising candidates (Shaltev et al 2014 Phys. Rev. D 89 124030). In this paper we present a set of techniques able to fulfill such requirements, identifying and eliminating false candidate events, reducing thus the bulk of candidate sets that need to be further investigated. Some of these techniques were also used to streamline the candidate sets returned by the Einstein@Home hierarchical searches presented in (Aasi J et al (The LIGO Scientific Collaboration and the Virgo Collaboration) 2013 Phys. Rev. D 87 042001). These powerful methods and the benefits originating from their application to both simulated and on detector data from the fifth LIGO science run are illustrated and discussed. (paper)
A comparison of methods for gravitational wave burst searches from LIGO and Virgo
Energy Technology Data Exchange (ETDEWEB)
Beauville, F; Buskulic, D; Grosjean, D [Laboratoire d' Annecy-le-Vieux de Physique des Particules, Chemin de Bellevue, BP 110, 74941 Annecy-le-Vieux Cedex (France); Bizouard, M-A; Cavalier, F; Clapson, A-C; Hello, P [Laboratoire de l' Accelerateur Lineaire, IN2P3/CNRS-Universite de Paris XI, BP 34, 91898 Orsay Cedex (France); Blackburn, L; Katsavounidis, E [LIGO-Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Bosi, L [INFN Sezione di Perugia and/or Universita di Perugia, Via A Pascoli, I-06123 Perugia (Italy); Brocco, L [INFN Sezione di Roma and/or Universita ' La Sapienza' , P le A Moro 2, I-00185 Roma (Italy); Brown, D A; Chatterji, S [LIGO-California Institute of Technology, Pasadena, CA 91125 (United States); Christensen, N; Knight, M [Carleton College, Northfield, MN 55057 (United States); Fairhurst, S [University of Wisconsin-Milwaukee, Milwaukee, WI 53201 (United States); Guidi, G [INFN Sezione Firenze/Urbino Via G Sansone 1, I-50019 Sesto Fiorentino (Italy); and/or Universita di Firenze, Largo E Fermi 2, I-50125 Firenze and/or Universita di Urbino, Via S Chiara 27, I-61029 Urbino (Italy); Heng, S; Hewitson, M [University of Glasgow, Glasgow, G12 8QQ (United Kingdom); Klimenko, S [University of Florida-Gainesville, FL 32611 (United States)] (and others)
2008-02-21
The search procedure for burst gravitational waves has been studied using 24 h of simulated data in a network of three interferometers (Hanford 4 km, Livingston 4 km and Virgo 3 km are the example interferometers). Several methods to detect burst events developed in the LIGO Scientific Collaboration (LSC) and Virgo Collaboration have been studied and compared. We have performed coincidence analysis of the triggers obtained in the different interferometers with and without simulated signals added to the data. The benefits of having multiple interferometers of similar sensitivity are demonstrated by comparing the detection performance of the joint coincidence analysis with LSC and Virgo only burst searches. Adding Virgo to the LIGO detector network can increase by 50% the detection efficiency for this search. Another advantage of a joint LIGO-Virgo network is the ability to reconstruct the source sky position. The reconstruction accuracy depends on the timing measurement accuracy of the events in each interferometer, and is displayed in this paper with a fixed source position example.
Schubert, G.; Anderson, J. D.
2013-12-01
Titan's gravitational field is inferred from an analysis of archived radio Doppler data for six Cassini flybys. The analysis considers each flyby separately in contrast to the approach of lumping all the data together in a massive inversion. In this way it is possible to gain an improved understanding of the character of each flyby and its usefulness in constraining the gravitational coefficient C22 . Though our analysis is not yet complete and our final determination of C22 could differ from the result we report here by 1 or 2 sigma, we find a best-fit value of C22 equal to (13.21 × 0.17) × 10-6, significantly larger than the value of 10.0 × 10-6 obtained from an inversion of the lumped Cassini data. We also find no determination of the tidal Love number k2. The larger value of C22 implies a moment of inertia factor equal to 0.3819 × 0.0020 and a less differentiated Titan than is suggested by the smaller value. The larger value of C22 is consistent with an undifferentiated model of the satellite. While it is not possible to rule out either value of C22 , we prefer the larger value because its derivation results from a more hands on analysis of the data that extracts the weak hydrostatic signal while revealing the effects of gravity anomalies and unmodeled spacecraft accelerations on each of the six flybys.
UCN gravitational spectrometer
International Nuclear Information System (INIS)
Kawabata, Yuji
1988-01-01
Concept design is carried out of two types of ultra cold neutron scallering equipment using the fall-focusing principle. One of the systems comprises a vertical gravitational spectrometer and the other includes a horizontal gravitation analyzer. A study is made of their performance and the following results are obtained. Fall-focusing type ultra cold neutron scattering equipment can achieve a high accuracy for measurement of energy and momentum. Compared with conventional neutron scattering systems, this type of equipment can use neutron very efficiently because scattered neutrons within a larger solid angle can be used. The maximum solid angle is nearly 4π and 2π for the vertical and horizontal type, respectively. Another feature is that the size of equipment can be reduced. In the present concept design, the equipment is spherical with a diameter of about 1 m, as compared with NESSIE which is 6.7 m in length and 4.85 m in height with about the same accuracy. Two horizontal analyzers and a vertical spectroscope are proposed. They are suitable for angle-dependent non-elastic scattering in the neutron velocity range of 6∼15 m/s, pure elastic scattering in the range of 4∼7 m/s, or angle-integration non-elastic scattering in the range of 4∼15 m/s. (N.K.)
General Relativity and Gravitation
Ashtekar, Abhay; Berger, Beverly; Isenberg, James; MacCallum, Malcolm
2015-07-01
Part I. Einstein's Triumph: 1. 100 years of general relativity George F. R. Ellis; 2. Was Einstein right? Clifford M. Will; 3. Cosmology David Wands, Misao Sasaki, Eiichiro Komatsu, Roy Maartens and Malcolm A. H. MacCallum; 4. Relativistic astrophysics Peter Schneider, Ramesh Narayan, Jeffrey E. McClintock, Peter Mészáros and Martin J. Rees; Part II. New Window on the Universe: 5. Receiving gravitational waves Beverly K. Berger, Karsten Danzmann, Gabriela Gonzalez, Andrea Lommen, Guido Mueller, Albrecht Rüdiger and William Joseph Weber; 6. Sources of gravitational waves. Theory and observations Alessandra Buonanno and B. S. Sathyaprakash; Part III. Gravity is Geometry, After All: 7. Probing strong field gravity through numerical simulations Frans Pretorius, Matthew W. Choptuik and Luis Lehner; 8. The initial value problem of general relativity and its implications Gregory J. Galloway, Pengzi Miao and Richard Schoen; 9. Global behavior of solutions to Einstein's equations Stefanos Aretakis, James Isenberg, Vincent Moncrief and Igor Rodnianski; Part IV. Beyond Einstein: 10. Quantum fields in curved space-times Stefan Hollands and Robert M. Wald; 11. From general relativity to quantum gravity Abhay Ashtekar, Martin Reuter and Carlo Rovelli; 12. Quantum gravity via unification Henriette Elvang and Gary T. Horowitz.
On geometrized gravitation theories
International Nuclear Information System (INIS)
Logunov, A.A.; Folomeshkin, V.N.
1977-01-01
General properties of the geometrized gravitation theories have been considered. Geometrization of the theory is realized only to the extent that by necessity follows from an experiment (geometrization of the density of the matter Lagrangian only). Aor a general case the gravitation field equations and the equations of motion for matter are formulated in the different Riemann spaces. A covariant formulation of the energy-momentum conservation laws is given in an arbitrary geometrized theory. The noncovariant notion of ''pseudotensor'' is not required in formulating the conservation laws. It is shown that in the general case (i.e., when there is an explicit dependence of the matter Lagrangian density on the covariant derivatives) a symmetric energy-momentum tensor of the matter is explicitly dependent on the curvature tensor. There are enlisted different geometrized theories that describe a known set of the experimental facts. The properties of one of the versions of the quasilinear geometrized theory that describes the experimental facts are considered. In such a theory the fundamental static spherically symmetrical solution has a singularity only in the coordinate origin. The theory permits to create a satisfactory model of the homogeneous nonstationary Universe
International Nuclear Information System (INIS)
Burinskii, A.
2015-01-01
The Kerr–Newman (KN) black hole (BH) solution exhibits the external gravitational and electromagnetic field corresponding to that of the Dirac electron. For the large spin/mass ratio, a ≫ m, the BH loses horizons and acquires a naked singular ring creating two-sheeted topology. This space is regularized by the Higgs mechanism of symmetry breaking, leading to an extended particle that has a regular spinning core compatible with the external KN solution. We show that this core has much in common with the known MIT and SLAC bag models, but has the important advantage of being in accordance with the external gravitational and electromagnetic fields of the KN solution. A peculiar two-sheeted structure of Kerr’s gravity provides a framework for the implementation of the Higgs mechanism of symmetry breaking in configuration space in accordance with the concept of the electroweak sector of the Standard Model. Similar to other bag models, the KN bag is flexible and pliant to deformations. For parameters of a spinning electron, the bag takes the shape of a thin rotating disk of the Compton radius, with a ring–string structure and a quark-like singular pole formed at the sharp edge of this disk, indicating that the considered lepton bag forms a single bag–string–quark system
Gravitational Waves - New Perspectives
International Nuclear Information System (INIS)
Biesiada, M.
1999-01-01
Laser interferometric experiments planned for 2002 will open up a new window onto the Universe. The first part of the paper gives a brief intuitive introduction to gravity waves, detection techniques and enumeration of main astrophysical sources and frequency bands to which they contribute. Then two more specific issues are discussed concerning cosmological perspectives of gravity waves detection. First one is the problem of gravitational lensing of the signal from inspiralling NS-NS binaries. The magnitude of the so called magnification bias is estimated and found non-negligible for some quite realistic lens models, but strongly model-dependent. The second problem is connected with estimates of galactic and extragalactic parts of the stochastic background. The main conclusion from these two examples is that in so far as the cosmological payoff of gravitational wave detection would be high, we should substantially deepen our understanding of basic astrophysical properties of galaxies and their clusters (in terms of mass distribution) in order to draw clear cosmological conclusions. (author)
Collett, Thomas E; Bacon, David
2017-03-03
Probing the relative speeds of gravitational waves and light acts as an important test of general relativity and alternative theories of gravity. Measuring the arrival time of gravitational waves (GWs) and electromagnetic (EM) counterparts can be used to measure the relative speeds, but only if the intrinsic time lag between emission of the photons and gravitational waves is well understood. Here we suggest a method that does not make such an assumption, using future strongly lensed GW events and EM counterparts; Biesiada et al. [J. Cosmol. Astropart. Phys.10 (2014) 080JCAPBP1475-751610.1088/1475-7516/2014/10/080] forecast that 50-100 strongly lensed GW events will be observed each year with the Einstein Telescope. A single strongly lensed GW event would produce robust constraints on c_{GW}/c_{γ} at the 10^{-7} level, if a high-energy EM counterpart is observed within the field of view of an observing γ-ray burst monitor.
Speed of Gravitational Waves from Strongly Lensed Gravitational Waves and Electromagnetic Signals.
Fan, Xi-Long; Liao, Kai; Biesiada, Marek; Piórkowska-Kurpas, Aleksandra; Zhu, Zong-Hong
2017-03-03
We propose a new model-independent measurement strategy for the propagation speed of gravitational waves (GWs) based on strongly lensed GWs and their electromagnetic (EM) counterparts. This can be done in two ways: by comparing arrival times of GWs and their EM counterparts and by comparing the time delays between images seen in GWs and their EM counterparts. The lensed GW-EM event is perhaps the best way to identify an EM counterpart. Conceptually, this method does not rely on any specific theory of massive gravitons or modified gravity. Its differential setting (i.e., measuring the difference between time delays in GW and EM domains) makes it robust against lens modeling details (photons and GWs travel in the same lensing potential) and against internal time delays between GW and EM emission acts. It requires, however, that the theory of gravity is metric and predicts gravitational lensing similar to general relativity. We expect that such a test will become possible in the era of third-generation gravitational-wave detectors, when about 10 lensed GW events would be observed each year. The power of this method is mainly limited by the timing accuracy of the EM counterpart, which for kilonovae is around 10^{4} s. This uncertainty can be suppressed by a factor of ∼10^{10}, if strongly lensed transients of much shorter duration associated with the GW event can be identified. Candidates for such short transients include short γ-ray bursts and fast radio bursts.
Fisher, Ryan Patrick; Hughey, Brennan; Howell, Eric; LIGO Collaboration
2018-01-01
Although Fast Radio Bursts (FRB) are being detected with increasing frequency, their progenitor systems are still mostly a mystery. We present the plan to conduct targeted searches for gravitational-wave counterparts to these FRB events in the data from the first and second observing runs of the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO).
LOCALIZATION AND BROADBAND FOLLOW-UP OF THE GRAVITATIONAL-WAVE TRANSIENT GW 150914
Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adams, C.; Phythian-Adams, A.T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Agathos, M.; Agatsuma, K.; Aggarwal, N.T.; 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, R.D.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Barthelmy, S.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Baune, C.; Bavigadda, V.; Bazzan, M.; Behnke, B.; Bejger, M.; Bell, A. S.; Bell, C. J.; Berger, B. K.; Bergman, J.; Bergmann, G.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Birch, M.J.; Birney, R.; Biscans, S.; Bisht, A.; Bitossi, M.; Bitossi, M.; Bizouard, M. A.; Blackburn, J. K.; Blair, C. D.; Blair, D. G.; Blair, R. M.; Bloemen, A.L.S.; Bock, O.; Bodiya, T. P.; Boer, M.; Bogaert, J.G.; Bogan, C.; Bohe, A.; Bojtos, P.; Bond, T.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, A.D.; Brown, D.; Brown, N. M.; Buchanan, C. C.; Buikema, A.; Bulik, T.; Bulten, H. J.; Buonanno, A.; Buskulic, D.; Buy, C.; Byer, R. L.; Cadonati, L.; Cagnoli, G.; Cahillane, C.; Bustillo, J. Calderon; Callister, T. A.; 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.; Cavaglia, 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, D. 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, Qian; Chua, S. S. Y.; Chung, E.S.; Ciani, G.; Clara, F.; Clark, J. A.; Clark, J. A.; Coccia, E.; Cohadon, P. -F.; Colla, A.; Collette, C. G.; Cominsky, L.; Constancio, M., Jr.; Conte, A.; Conti, L.; Cook, D.; Corbitt, T. R.; Cornish, N.; Corsi, A.; Cortese, S.; Costa, A.C.; 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, Laura; 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.; Deleglise, S.; Del Pozzo, W.; Denker, T.; Dent, T.; Dereli, H.; Dergachev, V.A.; DeRosa, R. T.; Rosa, R.; DeSalvo, R.; Dhurandhar, S.; Diaz, M. C.; Di Fiore, L.; Giovanni, M. Di; 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, T. M.; Evans, T. M.; Everett, R.; Factourovich, M.; Fafone, V.; Fair, H.; Fairhurst, S.; Fan, X.M.; 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.; Gendre, B.; Genin, E.; Gennai, A.; George, J.; Gergely, L.; Germain, V.; Ghosh, A.; Ghosh, S.; Giaime, J. A.; Giardina, K. D.; Giazotto, A.; Gill, K.P.; Glaefke, A.; Goetz, E.; Goetz, R.; Gondan, L.; Gonzalez, Idelmis G.; Castro, J. M. Gonzalez; Gopakumar, A.; Gordon, N. A.; Gorodetsky, M. L.; Gossan, S. E.; Lee-Gosselin, M.; Gouaty, R.; Graef, C.; Graff, P. B.; Granata, M.; Grant, A.; Gras, S.; Gray, C.M.; Greco, G.; Green, A. C.; Groot, P.; Grote, H.; Grunewald, S.; Guidi, G. M.; Guo, X.; Gupta, A.; Gupta, M. K.; Gushwa, K. E.; Gustafson, E. K.; Gustafson, R.; Hacker, J. J.; Buffoni-Hall, R.; Hall, E. D.; Hammond, G.L.; Haney, M.; Hanke, M. M.; Hanks, J.; Hanna, C.; Hannam, M. D.; Hanson, P.J.; Hardwick, T.; Haris, K.; Harms, J.; Harry, G. M.; Harry, I. W.; Hart, M. J.; Hartman, M. T.; Haster, C. -J.; Haughian, K.; Heidmann, A.; Heintze, M. C.; Heitmann, H.; Hello, P.; Hello, P.; Hendry, M.; Heng, I. S.; Hennig, J.; Heptonstall, A. W.; Heurs, M.; Hild, S.; Hoak, D.; Hodge, K. A.; Hofman, D.; Hollitt, S. E.; Holt, K.; Holz, D. E.; Hopkins, P.; Hosken, D. J.; Hough, J.; Houston, E. A.; Howell, E. J.; Hu, Y. M.; Huang, S.; Huerta, E. A.; Huet, D.; Hughey, B.; Husa, S.; Huttner, S. H.; Huynh-Dinh, T.; Idrisy, A.; Indik, N.; Ingram, D. R.; Inta, R.; Isa, H. N.; Isac, J. -M.; Isi, M.; Islas, G.; Isogai, T.; Iyer, B. R.; Izumi, K.; Jacqmin, T.; Jang, D.H.; Jani, K.; Jaranowski, P.; Jawahar, S.; Jimenez-Forteza, F.; Johnson, W.; Jones, I.D.; Jones, R.; Jonker, R. J. G.; Ju, L.; Kalaghatgi, C. V.; Kalogera, V.; Kandhasamy, S.; Kang, G.H.; Kanner, J. B.; Karki, S.; Kasprzack, M.; Katsavounidis, E.; Katzman, W.; Kaufer, S.; Kaur, T.; Kawabe, K.; Kawazoe, F.; Kefelian, F.; Kehl, M. S.; Keitel, D.; Kelley, D. B.; Kells, W.; Kennedy, R.E.; 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, Namjun; Kim, Namjun; Kim, Y.M.; King, E. J.; King, P. J.; Kinzel, D. L.; Kissel, J. S.; Kleybolte, L.; Klimenko, S.; Koehlenbeck, S. M.; Kokeyama, K.; Koley, S.; Kondrashov, V.; Kontos, A.; Korobko, M.; Korth, W. Z.; Kowalska, I.; Kozak, D. B.; Kringel, V.; Krolak, A.; Krueger, C.; Kuehn, G.; Kumar, P.; Kuo, L.; Kuo, L.; 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, K.H.; Lee, M.H.; 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.; Losurdo, G.; Lueck, H.; Lundgren, A. P.; Luo, J.; Lynch, R.; Ma, Y.; MacDonald, T.T.; Machenschalk, B.; MacInnis, M.; Macleod, D. M.; Magana-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.; Marka, S.; Marka, 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. L.; 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, J.C.; Moraru, D.; Gutierrez Moreno, M.; Morriss, S. R.; Mossavi, K.; Mossavi, K.; Mow-Lowry, C. M.; Mueller, C. L.; Mueller, G.; Muir, A. W.; Mukherjee, A.; Mukherjee, S.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.; Gutierrez-Neri, M.; Neunzert, A.; Newton-Howes, 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.; Oh, S. H.; Ohme, F.; Oliver, M. B.; 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.; Palliyaguru, N.; Palomba, C.; Pal-Singh, A.; Pan, H.; Pankow, C.; Pannarale, F.; Pant, B. C.; Paoletti, F.; Paoli, A.; Papa, M. A.; Paris, H. R.; Parker, W.S; 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. J.; 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. G.; Puncken, O.; Punturo, M.; Puppo, P.; Puerrer, 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.; Rosinska, D.; Rowan, S.; Ruediger, A.; Ruggi, P.; Ryan, K.A.; Sachdev, Perminder 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.; Sanders, J. R.; Sathyaprakash, B. S.; Saulson, P. R.; Sauter, O.; Savage, R. L.; Sawadsky, A.; Schale, P.; Schilling, R.; Schmidt, J; Schmidt, P.; Schnabel, R.B.; Schofield, R. M. S.; Schoenbeck, A.; Schreiber, K.E.C.; Schuette, D.; Schutz, B. F.; Scott, J.; Scott, M.S.; Sellers, D.; Sentenac, D.; Sequino, V.; Sergeev, A.; Serna, G.; Setyawati, Y.; Sevigny, A.; Shaddock, D. A.; Shah, S.; Shahriar, M. S.; Shaltev, M.; Shao, Z.M.; Shapiro, B.; Shawhan, P.; Sheperd, A.; Shoemaker, D. H.; Shoemaker, D. M.; Siellez, K.; Siemens, X.; Sigg, D.; Silva, António Dias da; Simakov, D.; Singer, A; Singh, A.; Singh, R.; Singhal, A.; Sintes, A. M.; Slagmolen, B. J. J.; Smith, R. J. E.; Smith, N.D.; Smith, R. J. E.; Son, E. J.; Sorazu, B.; Sorrentino, F.; Souradeep, T.; Souradeep, T.; Staley, A.; Steinke, M.; Steinlechner, J.; Steinlechner, S.; Steinmeyer, D.; Stephens, B. C.; Stone, J.R.; Strain, K. A.; Straniero, N.; Stratta, G.; Strauss, N. A.; Strigin, S. E.; Sturani, R.; Stuver, A. L.; Summerscales, T. Z.; Sun, L.; Sutton, P. J.; Swinkels, B. L.; Szczepanczyk, M. J.; Tacca, M.D.; Talukder, D.; Tanner, D. B.; Tapai, M.; Tarabrin, S. P.; Taracchini, A.; Taylor, W.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.; Toyra, D.; Travasso, F.; Traylor, G.; Trifiro, D.; Tringali, M. C.; Trozzo, L.; Tse, M.; Turconi, M.; Tuyenbayev, D.; Ugolini, D.; Unnikrishnan, C. S.; Urban, A. L.; Vahlbruch, H.; Vajente, G.; Valdes, G.; van Bakel, N.; Van Beuzekom, Martin; van den Brand, J. F. J.; Van Den Broeck, C.F.F.; Vander-Hyde, D. C.; van der Schaaf, L.; van Heijningen, J. V.; van Veggel, A. A.; Vardaro, M.; Vass, S.; Vasuth, M.; Vaulin, R.; Vecchio, A.; Vedovato, G.; Veitch, J.; Veitch, P.J.; Venkateswara, K.; Verkindt, D.; Vetrano, F.; Vicere, A.; Vinciguerra, S.; Vine, D. J.; Vinet, J. -Y.; Vitale, S.; Vo, T.; Vocca, H.; Vorvick, C.; Voss, D. V.; Vousden, W. D.; Vyatchanin, S. P.; Wade, A. R.; Wade, L. E.; Wade, MT; 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.M.; Wessels, P.; Westphal, T.; Wette, K.; Whelan, J. T.; White, D. J.; Whiting, B. F.; Williams, D.R.; 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.; Zadrozny, 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.; Allison, J.; Bannister, K.; Bell, E.M.; Chatterjee, S.; Chippendale, A. P.; Edwards, P. G.; Harvey-Smith, L.; Heywood, Ian; Hotan, A.; Indermuehle, B.; Marvil, J.; McConnell, D.; Murphy, Michael T.; Popping, A.; Reynolds, J.; Sault, R. J.; Voronkov, M. A.; Whiting, M. T.; Castro-Tirado, A. J.; Cunniffe, R.; Jelinek, M.; Tello, J. C.; Oates, S. R.; Hu, Y. -D.; Kubanek, P.; Guziy, S.; Castellon, A.; Garcia-Cerezo, A.; Munoz, V. F.; Perez del Pulgar, C.; Castillo-Carrion, S.; Hudec, R.; Caballero-Garcia, M. D.; Pata, P.; Vitek, S.; Adame, J. A.; Konig, S.; Rendon, F.; Mateo Sanguino, T. de J.; Munoz-Fernandez, R.; Yock, P. C.; Rattenbury, N.; Allen, W. H.; Querel, R.; Jeong, S.; Park, I. H.; Bai, J.C.; Cui, Ch.; Fan, Y.; Wang, Ch.; Hiriart, D.; Lee, W. H.; Claret, A.; Sanchez-Ramirez, R.; Pandey, S. B.; Mediavilla, T.; Sabau-Graziati, L.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Armstrong, R.; Benoit-Levy, A.; Berger, Charles E H; Bernstein, R. A.; Bertin, E.; Brout, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carretero, J.; Castander, F. J.; Chornock, R.; Cowperthwaite, P. S.; Cowperthwaite, P. S.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doctor, Z.; Drlica-Wagner, A.; Drout, M. R.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Fong, W. -F.; Fosalba, P.; Fox, D. B.; Frieman, J.; Fryer, C. L.; Gaztanaga, E.; Gerdes, D. W.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, A.G.; Herner, K.; Honscheid, K.; James, J. D Mireles; Johnson, M.D.; Johnson, M. W. G.; Karliner, I.; Kasen, D.; Kent, S.; Kessler, R.; Kim, A. G.; Kind, M. C.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Lin, H.H.; Maia, M. A. G.; Margutti, R.; Marriner, J.; San Martini, P.; Matheson, T.; Melchior, P.; Metzger, B. D.; Miller, C. J.; Miquel, R.; Neilsen, E.; Nichol, R. C.; Nord, B.; Nugent, P.; Ogando, R.; Petravick, D.; Plazas, A. A.; Quataert, E.; Roe, N. A.; Romer, A. K.; Roodman, A.; Rosell, A. C.; Rykoff, E. S.; Sako, M.; Sanchez, E.; Scarpine, V.; Schindler, R. H.; Schubnell, M.; Scolnic, D.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, N.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Stebbins, A.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Thomas, D.; Thomas, C.R.; Tucker, D. L.; Tucker, D. L.; Walker, A. R.; Wechsler, R. H.; Wester, W.; Yanny, B.; Zhang, Y.; Zuntz, J.; Connaughton, V.; Burns, J.E.; Goldstein, A.; Briggs, M. S.; Zhang, B.; Hui, C. M.; Jenke, P.; Wilson-Hodge, C. A.; Bhat, P. N.; Bissaldi, E.; Cleveland, W.; Fitzpatrick, G.; Giles, M. M.; Gibby, M. H.; Greiner, J.; von Kienlin, A.; Kippen, R. M.; McBreen, S.; Mailyan, B.; Meegan, C. A.; Paciesas, W. S.; Preece, R. D.; Roberts, W.O.; Sparke, L.; Stanbro, M.; Toelge, K.; Veres, P.; Yu, H. -F.; Blackburn, L.; Ackermann, M; Ajello, M.; Albert, M.A.; Anderson, B.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonino, R.; Bottacini, E.; Brandt, T. J.; Brandt, T. J.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caragiulo, M.; Caraveo, P. A.; Cavazzuti, E.; Charles, E.; Chekhtman, A.; Chiang, J.; Chiaro, G.; Ciprini, S.; Cohen-Tanugi, J.; Cominsky, L. R.; Costanza, F.; Cuoco, A.; D'Ammando, F.; de Palma, F.; Desiante, R.; Desiante, R.; Di Lalla, N.; Di Mauro, M.; Di Venere, L.; Dominguez, A.; Drell, P. S.; DuBois, RN; Favuzzi, C.; Ferrara, E. C.; Franckowiak, A.; Fukazawa, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Giglietto, N.; Giommi, P.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Gomez-Vargas, G. A.; Green, D.; Grenier, I. A.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Harding, A. K.; Hays, E.; Hewitt, J. W.; Hill, A. B.; Horan, D.; Jogler, T.; Johannesson, G.; Johnson, A.S.; Kensei, S.; Kocevski, D.; Kuss, M.; La Mura, G.; Larsson, S.; Latronico, L.; Li, J.; Li, L.; Lopez-Longo, F.J.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Magill, J.; Maldera, S.; Manfreda, A.; Marelli, M.; Mayer, M.; Mazziotta, M. N.; McEnery, J. E.; Meyer, M.; Michelson, P. F.; Mirabal, N.; Mizuno, T.; Moiseev, A. A.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Negro, M.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orienti, M.; Orlando, E.; Ormes, J. F.; Paneque, D.; Perkins, J. S.; Pesce-Rollins, M.
2016-01-01
A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098 and later given the name GW150914, is described in detail elsewhere. By prior
Numerical investigations of gravitational collapse
Energy Technology Data Exchange (ETDEWEB)
Csizmadia, Peter; Racz, Istvan, E-mail: iracz@rmki.kfki.h [RMKI, Budapest, Konkoly Thege Miklos ut 29-33, H-1121 (Hungary)
2010-03-01
Some properties of a new framework for simulating generic 4-dimensional spherically symmetric gravitating systems are discussed. The framework can be used to investigate spacetimes that undergo complete gravitational collapse. The analytic setup is chosen to ensure that our numerical method is capable to follow the time evolution everywhere, including the black hole region.
On the gravitational radiation formula
International Nuclear Information System (INIS)
Schaefer, G.; Dehnen, H.
1980-01-01
For electromagnetically as well as gravitationally bound quantum mechanical many-body systems the coefficients of absorption and induced emission of gravitational radiation are calculated in the first-order approximation. The results are extended subsequently to systems with arbitrary non-Coulomb-like two-particle interaction potentials;it is shown explicitly that in all cases the perturbation of the binding potentials of the bound systems by the incident gravitational wave field itself must be taken into account. With the help of the thermodynamic equilibrium of gravitational radiation and quantised matter, the coefficients for spontaneous emission of gravitational radiation are derived and the gravitational radiation formula for emission of gravitational quadrupole radiation by bound quantum mechanical many-body systems is given. According to the correspondence principle the present result is completely identical with the well known classical radiation formula, by which recent criticism against this formula is refuted. Finally the quantum mechanical absorption cross section for gravitational quadrupole radiation is deduced and compared with the corresponding classical expressions. As a special example the vibrating two-mass quadrupole is treated explicitly. (author)
To theory of gravitational interaction
Minkevich, A. V.
2008-01-01
Some principal problems of general relativity theory and attempts of their solution are discussed. The Poincare gauge theory of gravity as natural generalization of Einsteinian gravitation theory is considered. The changes of gravitational interaction in the frame of this theory leading to the solution of principal problems of general relativity theory are analyzed.
Gravitational Casimir–Polder effect
Directory of Open Access Journals (Sweden)
Jiawei Hu
2017-04-01
Full Text Available The interaction due to quantum gravitational vacuum fluctuations between a gravitationally polarizable object modelled as a two-level system and a gravitational boundary is investigated. This quantum gravitational interaction is found to be position-dependent, which induces a force in close analogy to the Casimir–Polder force in the electromagnetic case. For a Dirichlet boundary, the quantum gravitational potential for the polarizable object in its ground-state is shown to behave like z−5 in the near zone, and z−6 in the far zone, where z is the distance to the boundary. For a concrete example, where a Bose–Einstein condensate is taken as a gravitationally polarizable object, the relative correction to the radius of the BEC caused by fluctuating quantum gravitational waves in vacuum is found to be of order 10−21. Although the correction is far too small to observe in comparison with its electromagnetic counterpart, it is nevertheless of the order of the gravitational strain caused by a recently detected black hole merger on the arms of the LIGO.
Exact piecewise flat gravitational waves
van de Meent, M.
2011-01-01
We generalize our previous linear result (van de Meent 2011 Class. Quantum Grav 28 075005) in obtaining gravitational waves from our piecewise flat model for gravity in 3+1 dimensions to exact piecewise flat configurations describing exact planar gravitational waves. We show explicitly how to
Laboratory generation of gravitational waves
International Nuclear Information System (INIS)
Pinto, I.M.; Rotoli, G.
1988-01-01
The authors have performed calculations on the basic type of gravitational wave electromagnetic laboratory generators. Their results show that laboratory generations of gravitational wave is at limit of state-of-the-art of present-day giant electromagnetic field generation
The gravitational properties of antimatter
International Nuclear Information System (INIS)
Goldman, T.; Hughes, R.J.; Nieto, M.M.
1986-09-01
It is argued that a determination of the gravitational acceleration of antimatter towards the earth is capable of imposing powerful constraints on modern quantum gravity theories. Theoretical reasons to expect non-Newtonian non-Einsteinian effects of gravitational strength and experimental suggestions of such effects are reviewed. 41 refs
Interaction of gravitational plane waves
International Nuclear Information System (INIS)
Ferrari, V.
1988-01-01
The mathematical theory of colliding, infinite-fronted, plane gravitational waves is presented. The process of focusing, the creation of singularities and horizons, due to the interaction, and the lens effect due to a beam-like gravitational wave are discussed
Critical Effects in Gravitational Collapse
International Nuclear Information System (INIS)
Chmaj, T.
2000-01-01
The models of gravitational collapse of a dynamical system are investigated by means of the Einstein equations. Different types conjunctions to gravitational field are analyzed and it is shown that in the case of week scalar field (low energy density) the system evaluated to flat space while in the case of strong field (high energy density) to black hole
Conservation laws and gravitational radiation
International Nuclear Information System (INIS)
Rastall, P.
1977-01-01
A total stress-momentum is defined for gravitational fields and their sources. The Lagrangian density is slightly different from that in the previous version of the theory, and the field equations are considerably simplified. The post-Newtonian approximation of the theory is unchanged. The existence and nature of weak gravitational waves are discussed. (author)
Vignettes in Gravitation and Cosmology
Sriramkumar, L
2012-01-01
This book comprises expository articles on different aspects of gravitation and cosmology that are aimed at graduate students. The topics discussed are of contemporary interest assuming only an elementary introduction to gravitation and cosmology. The presentations are to a certain extent pedagogical in nature, and the material developed is not usually found in sufficient detail in recent textbooks in these areas.
Rotation in a gravitational billiard
Peraza-Mues, G. G.; Carvente, Osvaldo; Moukarzel, Cristian F.
Gravitational billiards composed of a viscoelastic frictional disk bouncing on a vibrating wedge have been studied previously, but only from the point of view of their translational behavior. In this work, the average rotational velocity of the disk is studied under various circumstances. First, an experimental realization is briefly presented, which shows sustained rotation when the wedge is tilted. Next, this phenomenon is scrutinized in close detail using a precise numerical implementation of frictional forces. We show that the bouncing disk acquires a spontaneous rotational velocity whenever the wedge angle is not bisected by the direction of gravity. Our molecular dynamics (MD) results are well reproduced by event-driven (ED) simulations. When the wedge aperture angle θW>π/2, the average tangential velocity Rω¯ of the disk scales with the typical wedge vibration velocity vb, and is in general a nonmonotonic function of the overall tilt angle θT of the wedge. The present work focuses on wedges with θW=2π/3, which are relevant for the problem of spontaneous rotation in vibrated disk packings. This study makes part of the PhD Thesis of G. G. Peraza-Mues.
Are the gravitational waves quantised?
International Nuclear Information System (INIS)
Lovas, Istvan
1997-01-01
If the gravitational waves are classical objects then the value of their correlation function is 1. If they are quantised, then there exist two possibilities: the gravitational waves are either completely coherent, then their correlation function is again 1, or they are only partially coherent, then their correlation function is expected to deviate from 1. Unfortunately such a deviation is not a sufficient proof for the quantised character of the gravitational waves. If the gravitational waves are quantised and generated by the change of the background metrical then they can be in a squeezed state. In a squeezed state there is a chance for the correlation between the phase of the wave and the quantum fluctuations. The observation of such a correlation would be a genuine proof of the quantised character of the gravitational wave
DEFF Research Database (Denmark)
collaborative economy and tourism Dianne Dredge and Szilvia Gyimóthy PART I - Theoretical explorations 2.Definitions and mapping the landscape in the collaborative economy Szilvia Gyimóthy and Dianne Dredge 3.Business models of the collaborative economy Szilvia Gyimóthy 4.Responsibility and care...... in the collaborative economy Dianne Dredge 5.Networked cultures in the collaborative economy Szilvia Gyimóthy 6.Policy and regulatory perspectives in the collaborative economy Dianne Dredge PART II - Disruptions, innovations and transformations 7.Regulating innovation in the collaborative economy: An examination...... localities of tourism Greg Richards 11.Collaborative economy and destination marketing organizations: A systems approach Jonathan Day 12.Working within the Collaborative Tourist Economy: The complex crafting of work and meaning Jane Widtfeldt Meged and Mathilde Dissing Christensen PART - III Encounters...
High-intensification regions of gravitational lenses
International Nuclear Information System (INIS)
Benson, J.R.; Cooke, J.H.
1979-01-01
We examine the intensification, I, near the singular points in the object plane of an extended spherical gravitational lens. Geometrical optics predicts an infinite I for a point object located on a singularity. The function I, however, turns out to be integrable over the object plane. We make a detailed physical optics calculation for I. No singularities appear, and there are some interesting, marginally detectable diffraction phenomena. The two types of bright regions, the ''halo'' and the ''spike,'' behave very differently. Simple order-of-magnitude expressions give estimates for the brightness and duration of a high-intensification event
Cosmological constant and advanced gravitational wave detectors
International Nuclear Information System (INIS)
Wang, Y.; Turner, E.L.
1997-01-01
Interferometric gravitational wave detectors could measure the frequency sweep of a binary inspiral (characterized by its chirp mass) to high accuracy. The observed chirp mass is the intrinsic chirp mass of the binary source multiplied by (1+z), where z is the redshift of the source. Assuming a nonzero cosmological constant, we compute the expected redshift distribution of observed events for an advanced LIGO detector. We find that the redshift distribution has a robust and sizable dependence on the cosmological constant; the data from advanced LIGO detectors could provide an independent measurement of the cosmological constant. copyright 1997 The American Physical Society
Gravitational wave experiments
Hamilton, W O
1993-01-01
There were three oral sessions and one poster session for Workshop C1 on Gravitational Wave Experiments. There was also an informal experimental roundtable held one after- noon. The ﬁrst two oral sessions were devoted mainly to progress reports from various interferometric and bar detector groups. A total of 15 papers were presented in these two sessions. The third session of Workshop C1 was devoted primarily to theoretical and experimental investigations associated with the proposed interferometric detectors. Ten papers were presented in this session. In addition, there were a total of 13 papers presented in the poster session. There was some overlap between the presentations in the third oral session and the posters since only two of the serious posters were devoted to technology not pertinent to interferometers. In general, the papers showed the increasing maturity of the experimental aspects of the ﬁeld since most presented the results of completed investigations rather than making promises of wonderf...
Relativistic gravitational instabilities
International Nuclear Information System (INIS)
Schutz, B.F.
1987-01-01
The purpose of these lectures is to review and explain what is known about the stability of relativistic stars and black holes, with particular emphases on two instabilities which are due entirely to relativistic effects. The first of these is the post-Newtonian pulsational instability discovered independently by Chandrasekhar (1964) and Fowler (1964). This effectively ruled out the then-popular supermassive star model for quasars, and it sets a limit to the central density of white dwarfs. The second instability was also discovered by Chandrasekhar (1970): the gravitational wave induced instability. This sets an upper bound on the rotation rate of neutron stars, which is near that of the millisecond pulsar PSR 1937+214, and which is beginning to constrain the equation of state of neutron matter. 111 references, 5 figures
Atomic and gravitational clocks
International Nuclear Information System (INIS)
Canuto, V.M.; City Coll., New York; Goldman, I.
1982-01-01
Atomic and gravitational clocks are governed by the laws of electrodynamics and gravity respectively. While the strong equivalence principle (SEP) assumes that the two clocks have been synchronous at all times, recent planetary data seem to suggest a possible violation of the SEP. Past analysis of the implications of an SEP violation on different physical phenomena revealed no disagreement. However, these studies assumed that the two different clocks can be consistently constructed within the framework. The concept of scale invariance, and the physical meaning of different systems of units, are now reviewed and the construction of two clocks that do not remain synchronous-whose rates are related by a non-constant function βsub(a)-is demonstrated. The cosmological character of βsub(a) is also discussed. (author)
International Nuclear Information System (INIS)
Lopresto, J.C.; Chapman, R.D.
1980-01-01
Wavelengths of solar spectrum lines should be shifted toward the red by the Sun's gravitational field as predicted by metric theories of gravity according to the principle of equivalence. Photographic wavelengths of 738 solar Fe 1 lines and their corresponding laboratory wavelengths have been studied. The measured solar wavelength minus the laboratory wavelength (Δlambdasub(observed)) averaged for the strong lines agrees well with the theoretically predicted shift (Δlambdasub(theoretical)). Studies show that the departures depend on line strength. No dependence of the departures on wavelength was found within the existing data. By studying strong lines over a wide spectral range, velocity shifts caused by the complex motions in the solar atmosphere seem to affect the results in a minimal fashion. (orig.)
Observations of gravitational lenses
International Nuclear Information System (INIS)
Fort, B.
1990-01-01
During the last tow years a burst of results has come from radio and optical surveys of ''galaxy lenses'' (where the main deflector is a galaxy). These are reviewed. On the other hand, in September 1985 we pointed out a very strange blue ring-like structure on a Charge-Coupled Device image of the cluster of galaxies Abell 370. This turned out to be Einstein arcs discovery. Following this discovery, new observational results have shown that many rich clusters of galaxies can produce numerous arclets: tangentially distorted images of an extremely faint galaxy population probably located at redshift larger than 1. This new class of gravitational lenses proves to be an important observational topic and this will be discussed in the second part of the paper. (author)
Feynman Lectures on Gravitation
International Nuclear Information System (INIS)
Borcherds, P
2003-01-01
In the early 1960s Feynman lectured to physics undergraduates and, with the assistance of his colleagues Leighton and Sands, produced the three-volume classic Feynman Lectures in Physics. These lectures were delivered in the mornings. In the afternoons Feynman was giving postgraduate lectures on gravitation. This book is based on notes compiled by two students on that course: Morinigo and Wagner. Their notes were checked and approved by Feynman and were available at Caltech. They have now been edited by Brian Hatfield and made more widely available. The book has a substantial preface by John Preskill and Kip Thorne, and an introduction entitled 'Quantum Gravity' by Brian Hatfield. You should read these before going on to the lectures themselves. Preskill and Thorne identify three categories of potential readers of this book. 1. Those with a postgraduate training in theoretical physics. 2. 'Readers with a solid undergraduate training in physics'. 3. 'Admirers of Feynman who do not have a strong physics background'. The title of the book is perhaps misleading: readers in category 2 who think that this book is an extension of the Feynman Lectures in Physics may be disappointed. It is not: it is a book aimed mainly at those in category 1. If you want to get to grips with gravitation (and general relativity) then you need to read an introductory text first e.g. General Relativity by I R Kenyon (Oxford: Oxford University Press) or A Unified Grand Tour of Theoretical Physics by Ian D Lawrie (Bristol: IoP). But there is no Royal Road. As pointed out in the preface and in the introduction, the book represents Feynman's thinking about gravitation some 40 years ago: the lecture course was part of his attempts to understand the subject himself, and for readers in all three categories it is this that makes the book one of interest: the opportunity to observe how a great physicist attempts to tackle some of the hardest challenges of physics. However, the book was written 40
Blending in gravitational microlensing experiments : source confusion and related systematics
Smith, Martin C.; Wozniak, Przemyslaw; Mao, Shude; Sumi, Takahiro
2007-01-01
Gravitational microlensing surveys target very dense stellar fields in the local group. As a consequence, the microlensed source stars are often blended with nearby unresolved stars. The presence of 'blending' is a cause of major uncertainty when determining the lensing properties of events towards
The NANOGrav Nine-year Data Set: Limits on the Isotropic Stochastic Gravitational Wave Background
Arzoumanian, Zaven; Brazier, Adam; Burke-Spolaor, Sarah; Chamberlin, Sydney; Chatterjee, Shami; Christy, Brian; Cordes, Jim; Cornish, Neil; Demorest, Paul; Deng, Xihao; Dolch, Tim; Ellis, Justin; Ferdman, Rob; Fonseca, Emmanuel; Garver-Daniels, Nate
2015-01-01
We compute upper limits on the nanohertz-frequency isotropic stochastic gravitational wave background (GWB) using the 9-year data release from the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration. We set upper limits for a GWB from supermassive black hole binaries under power law, broken power law, and free spectral coefficient GW spectrum models. We place a 95\\% upper limit on the strain amplitude (at a frequency of yr$^{-1}$) in the power law model of $A...
Weight, gravitation, inertia, and tides
Pujol, Olivier; Lagoute, Christophe; Pérez, José-Philippe
2015-11-01
This paper deals with the factors that influence the weight of an object near the Earth's surface. They are: (1) the Earth's gravitational force, (2) the centrifugal force due to the Earth's diurnal rotation, and (3) tidal forces due to the gravitational field of the Moon and Sun, and other solar system bodies to a lesser extent. Each of these three contributions is discussed and expressions are derived. The relationship between weight and gravitation is thus established in a direct and pedagogical manner readily understandable by undergraduate students. The analysis applies to the Newtonian limit of gravitation. The derivation is based on an experimental (or operational) definition of weight, and it is shown that it coincides with the Earth’s gravitational force modified by diurnal rotation around a polar axis and non-uniformity of external gravitational bodies (tidal term). Two examples illustrate and quantify these modifications, respectively the Eötvös effect and the oceanic tides; tidal forces due to differential gravitation on a spacecraft and an asteroid are also proposed as examples. Considerations about inertia are also given and some comments are made about a widespread, yet confusing, explanation of tides based on a centrifugal force. Finally, the expression of the potential energy of the tide-generating force is established rigorously in the appendix.
Weight, gravitation, inertia, and tides
International Nuclear Information System (INIS)
Pujol, Olivier; Lagoute, Christophe; Pérez, José-Philippe
2015-01-01
This paper deals with the factors that influence the weight of an object near the Earth's surface. They are: (1) the Earth's gravitational force, (2) the centrifugal force due to the Earth's diurnal rotation, and (3) tidal forces due to the gravitational field of the Moon and Sun, and other solar system bodies to a lesser extent. Each of these three contributions is discussed and expressions are derived. The relationship between weight and gravitation is thus established in a direct and pedagogical manner readily understandable by undergraduate students. The analysis applies to the Newtonian limit of gravitation. The derivation is based on an experimental (or operational) definition of weight, and it is shown that it coincides with the Earth’s gravitational force modified by diurnal rotation around a polar axis and non-uniformity of external gravitational bodies (tidal term). Two examples illustrate and quantify these modifications, respectively the Eötvös effect and the oceanic tides; tidal forces due to differential gravitation on a spacecraft and an asteroid are also proposed as examples. Considerations about inertia are also given and some comments are made about a widespread, yet confusing, explanation of tides based on a centrifugal force. Finally, the expression of the potential energy of the tide-generating force is established rigorously in the appendix. (paper)
DEFF Research Database (Denmark)
that are emerging from them, and how governments are responding to these new challenges. In doing so, the book provides both theoretical and practical insights into the future of tourism in a world that is, paradoxically, becoming both increasingly collaborative and individualized. Table of Contents Preface 1.The...... collaborative economy and tourism Dianne Dredge and Szilvia Gyimóthy PART I - Theoretical explorations 2.Definitions and mapping the landscape in the collaborative economy Szilvia Gyimóthy and Dianne Dredge 3.Business models of the collaborative economy Szilvia Gyimóthy 4.Responsibility and care...... in the collaborative economy Dianne Dredge 5.Networked cultures in the collaborative economy Szilvia Gyimóthy 6.Policy and regulatory perspectives in the collaborative economy Dianne Dredge PART II - Disruptions, innovations and transformations 7.Regulating innovation in the collaborative economy: An examination...
DEFF Research Database (Denmark)
Holder, Anna; Lovett, George
2009-01-01
identified as a transformative global force of the last decade, most notably in knowledge and information publishing, communication and creation. This paper presents a structured conversation on changing understandings of collaboration, and the realities of collaborative methodology in architectural work...
Directory of Open Access Journals (Sweden)
Schnabel Roman
2013-08-01
Full Text Available This contribution reviews our recent progress on the generation of squeezed light [1], and also the recent squeezed-light enhancement of the gravitational wave detector GEO 600 [2]. GEO 600 is currently the only GW observatory operated by the LIGO Scientific Collaboration in its search for gravitational waves. With the help of squeezed states of light it now operates with its best ever sensitivity, which not only proves the qualification of squeezed light as a key technology for future gravitational wave astronomy but also the usefulness of quantum entanglement.
Gravitation. [Book on general relativity
Misner, C. W.; Thorne, K. S.; Wheeler, J. A.
1973-01-01
This textbook on gravitation physics (Einstein's general relativity or geometrodynamics) is designed for a rigorous full-year course at the graduate level. The material is presented in two parallel tracks in an attempt to divide key physical ideas from more complex enrichment material to be selected at the discretion of the reader or teacher. The full book is intended to provide competence relative to the laws of physics in flat space-time, Einstein's geometric framework for physics, applications with pulsars and neutron stars, cosmology, the Schwarzschild geometry and gravitational collapse, gravitational waves, experimental tests of Einstein's theory, and mathematical concepts of differential geometry.
Gravitational effects of global textures
International Nuclear Information System (INIS)
Noetzold, D.
1990-03-01
A solution for the dynamics of global textures is obtained. Their gravitational field during the collapse and the subsequent evolution is found to be given solely by a space-time dependent ''deficit solid angle.'' The frequency shift of photons traversing this gravitational field is calculated. The space-time dependent texture metric locally contracts the volume of three-space and thereby induces overdensities in homogeneous matter distributions. There are no gravitational forces unless matter has a nonzero angular momentum with respect to the texture origin which would be the case for moving textures
Anisotropic solutions by gravitational decoupling
Ovalle, J.; Casadio, R.; da Rocha, R.; Sotomayor, A.
2018-02-01
We investigate the extension of isotropic interior solutions for static self-gravitating systems to include the effects of anisotropic spherically symmetric gravitational sources by means of the gravitational decoupling realised via the minimal geometric deformation approach. In particular, the matching conditions at the surface of the star with the outer Schwarzschild space-time are studied in great detail, and we describe how to generate, from a single physically acceptable isotropic solution, new families of anisotropic solutions whose physical acceptability is also inherited from their isotropic parent.
Anisotropic solutions by gravitational decoupling
Energy Technology Data Exchange (ETDEWEB)
Ovalle, J. [Silesian University in Opava, Institute of Physics and Research Centre of Theoretical Physics and Astrophysics, Faculty of Philosophy and Science, Opava (Czech Republic); Universidad Simon Bolivar, Departamento de Fisica, Caracas (Venezuela, Bolivarian Republic of); Casadio, R. [Alma Mater Universita di Bologna, Dipartimento di Fisica e Astronomia, Bologna (Italy); Istituto Nazionale di Fisica Nucleare, Bologna (Italy); Rocha, R. da [Universidade Federal do ABC (UFABC), Centro de Matematica, Computacao e Cognicao, Santo Andre, SP (Brazil); Sotomayor, A. [Universidad de Antofagasta, Departamento de Matematicas, Antofagasta (Chile)
2018-02-15
We investigate the extension of isotropic interior solutions for static self-gravitating systems to include the effects of anisotropic spherically symmetric gravitational sources by means of the gravitational decoupling realised via the minimal geometric deformation approach. In particular, the matching conditions at the surface of the star with the outer Schwarzschild space-time are studied in great detail, and we describe how to generate, from a single physically acceptable isotropic solution, new families of anisotropic solutions whose physical acceptability is also inherited from their isotropic parent. (orig.)
Gravitational radiation quadrupole formula is valid for gravitationally interacting systems
International Nuclear Information System (INIS)
Walker, M.; Will, C.M.
1980-01-01
An argument is presented for the validity of the quadrupole formula for gravitational radiation energy loss in the far field of nearly Newtonian (e.g., binary stellar) systems. This argument differs from earlier ones in that it determines beforehand the formal accuracy of approximation required to describe gravitationally self-interacting systems, uses the corresponding approximate equation of motion explicitly, and evaluate the appropriate asymptotic quantities by matching along the correct space-time light cones
Gravitational waves and electrodynamics: new perspectives.
Cabral, Francisco; Lobo, Francisco S N
2017-01-01
Given the recent direct measurement of gravitational waves (GWs) by the LIGO-VIRGO collaboration, the coupling between electromagnetic fields and gravity have a special relevance since it opens new perspectives for future GW detectors and also potentially provides information on the physics of highly energetic GW sources. We explore such couplings using the field equations of electrodynamics on (pseudo) Riemann manifolds and apply it to the background of a GW, seen as a linear perturbation of Minkowski geometry. Electric and magnetic oscillations are induced that propagate as electromagnetic waves and contain information as regards the GW which generates them. The most relevant results are the presence of longitudinal modes and dynamical polarization patterns of electromagnetic radiation induced by GWs. These effects might be amplified using appropriate resonators, effectively improving the signal to noise ratio around a specific frequency. We also briefly address the generation of charge density fluctuations induced by GWs and the implications for astrophysics.
Gravitational waves and electrodynamics: new perspectives
Energy Technology Data Exchange (ETDEWEB)
Cabral, Francisco; Lobo, Francisco S.N. [Faculdade de Ciencias da Universidade de Lisboa, Instituto de Astrofisica e Ciencias do Espaco, Lisbon (Portugal)
2017-04-15
Given the recent direct measurement of gravitational waves (GWs) by the LIGO-VIRGO collaboration, the coupling between electromagnetic fields and gravity have a special relevance since it opens new perspectives for future GW detectors and also potentially provides information on the physics of highly energetic GW sources. We explore such couplings using the field equations of electrodynamics on (pseudo) Riemann manifolds and apply it to the background of a GW, seen as a linear perturbation of Minkowski geometry. Electric and magnetic oscillations are induced that propagate as electromagnetic waves and contain information as regards the GW which generates them. The most relevant results are the presence of longitudinal modes and dynamical polarization patterns of electromagnetic radiation induced by GWs. These effects might be amplified using appropriate resonators, effectively improving the signal to noise ratio around a specific frequency. We also briefly address the generation of charge density fluctuations induced by GWs and the implications for astrophysics. (orig.)
(Almost) All You Need to Know About Gravitational Wave Physics
CERN. Geneva
2016-01-01
General Relativity, some of which have been taken for granted without observations: are gravitons massless? Are black holes the simplest possible macroscopic objects? do event horizons and black holes really exist, or is their formation halted by some as-yet unknown mechanism? In these lectures, we will describe the anatomy of a GW event, with particular emphasis on how to compute gravitational-waves from black hole systems and what kind of information such waves carry.
International Nuclear Information System (INIS)
Faridah Mohammad Idris; Wan Ahmad Tajuddin Wan Abdullah; Zainol Abidin Ibrahim
2013-01-01
Full-text: CMS Collaboration is an international scientific collaboration located at European Organization for Nuclear Research (CERN), Switzerland, dedicated in carried out research on experimental particle physics. Consisting of 179 institutions from 41 countries from all around the word, CMS Collaboration host a general purpose detector for example the Compact Muon Solenoid (CMS) for members in CMS Collaboration to conduct experiment from the collision of two proton beams accelerated to a speed of 8 TeV in the LHC ring. In this paper, we described how the CMS detector is used by the scientist in CMS Collaboration to reconstruct the most basic building of matter. (author)
DEFF Research Database (Denmark)
collaborative economy and tourism Dianne Dredge and Szilvia Gyimóthy PART I - Theoretical explorations 2.Definitions and mapping the landscape in the collaborative economy Szilvia Gyimóthy and Dianne Dredge 3.Business models of the collaborative economy Szilvia Gyimóthy 4.Responsibility and care...... and similar phenomena are among these collective innovations in tourism that are shaking the very bedrock of an industrial system that has been traditionally sustained along commercial value chains. To date there has been very little investigation of these trends, which have been inspired by, amongst other...... in the collaborative economy Dianne Dredge 5.Networked cultures in the collaborative economy Szilvia Gyimóthy 6.Policy and regulatory perspectives in the collaborative economy Dianne Dredge PART II - Disruptions, innovations and transformations 7.Regulating innovation in the collaborative economy: An examination...
Stochastic backgrounds of gravitational waves
International Nuclear Information System (INIS)
Maggiore, M.
2001-01-01
We review the motivations for the search for stochastic backgrounds of gravitational waves and we compare the experimental sensitivities that can be reached in the near future with the existing bounds and with the theoretical predictions. (author)
Gravitational scattering of electromagnetic radiation
Brooker, J. T.; Janis, A. I.
1980-01-01
The scattering of electromagnetic radiation by linearized gravitational fields is studied to second order in a perturbation expansion. The incoming electromagnetic radiation can be of arbitrary multipole structure, and the gravitational fields are also taken to be advanced fields of arbitrary multipole structure. All electromagnetic multipole radiation is found to be scattered by gravitational monopole and time-varying dipole fields. No case has been found, however, in which any electromagnetic multipole radiation is scattered by gravitational fields of quadrupole or higher-order multipole structure. This lack of scattering is established for infinite classes of special cases, and is conjectured to hold in general. The results of the scattering analysis are applied to the case of electromagnetic radiation scattered by a moving mass. It is shown how the mass and velocity may be determined by a knowledge of the incident and scattered radiation.
Highlights in gravitation and cosmology
International Nuclear Information System (INIS)
Iyer, B.R.; Kembhavi, Ajit; Narlikar, J.V.; Vishveshwara, C.V.
1988-01-01
This book assesses research into gravitation and cosmology by examining the subject from various viewpoints: the classical and quantum pictures, along with the cosmological and astrophysical applications. There are 35 articles by experts of international standing. Each defines the state of the art and contains a concise summary of our present knowledge of a facet of gravitational physics. These edited papers are based on those first given at an international conference held in Goa, India at the end of 1987. The following broad areas are covered: classical relativity, quantum gravity, cosmology, black holes, compact objects, gravitational radiation and gravity experiments. In this volume there are also summaries of discussions on the following special topics: exact solutions of cosmological equations, mathematical aspects of general relativity, the early universe, and quantum gravity. For research workers in cosmology and gravitation this reference book provides a broad view of present achievements and current problems. (author)
International Nuclear Information System (INIS)
Logunov, A.A.
1989-01-01
The author believes that the General Relativity Theory (GRT) suffers from a substantial deficiency since it ignors the fundamental laws of conservation of energy. Einstein neglected the classical concept of the field due to his belief in the truth of the principle of equivalence between forces of inertid gravitation. This equivalence leads, as the author says, to nonequivalence of these forces, making GRT logically contradictory from the physical point of view. The author considers GRT as a certain stage in the course of the study of space-time and gravitation, and suggests a new theory called the Relativistic Theory of Gravitation (RTG) which obeys the fundamental laws of conservation, and which is justified in some of its aspects by astronomical observations. RTG does not suffer from some deficiencies met in Einsteins theory. One is nonunique predictions of gravitation effects within the boundaries of the solar system. Also, RTG refuses some hypothesis as that of black holes. 7 refs
Are the gravitational waves quantised?
International Nuclear Information System (INIS)
Lovas, I.
1998-01-01
The question whether gravitational waves are quantised or not can be investigated by the help of correlation measurements. If the gravitational waves are classical objects then the value of their correlation function is 1. However, if they are quantised, then there exist two possibilities: the gravitational waves are either completely coherent, then the correlation function is again 1, or they are partially coherent, then the correlation function is expected to deviate from 1. If the gravitational waves are generated by the change of the background metrics then they can be in a squeezed state. In a squeezed state there is a chance for the correlation between the phase of the wave and the quantum fluctuations. (author)
Heuristic introduction to gravitational waves
International Nuclear Information System (INIS)
Sandberg, V.D.
1982-01-01
The purpose of this article is to provide a rough and somewhat heuristic theoretical background and introduction to gravitational radiation, its generation, and its detection based on Einstein's general theory of relativity
Academic Training: Gravitational Waves Astronomy
2006-01-01
2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 16, 17, 18 October from 11:00 to 12:00 - Main Auditorium, bldg. 500 Gravitational Waves Astronomy M. LANDRY, LIGO Hanford Observatory, Richland, USA Gravitational wave astronomy is expected to become an observational field within the next decade. First direct detection of gravitational waves is possible with existing terrestrial-based detectors, and highly probable with proposed upgrades. In this three-part lecture series, we give an overview of the field, including material on gravitional wave sources, detection methods, some details of interferometric detectors, data analysis methods, and current results from observational data-taking runs of the LIGO and GEO projects. ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch If you wish to participate in one of the following courses, please tell to your supervisor and apply electronically from the course description pages that can be found on the Web at: http://www...
Event-by-event fluctuations at SPS
Appelshauser, Harald; Adamova, D.; Agakichiev, G.; Belaga, V.; Braun-Munzinger, P.; Castillo, A.; Cherlin, A.; Damjanovic, S.; Dietel, T.; Dietrich, L.; Drees, A.; Esumi, S.I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glassel, P.; Hering, G.; Holeczek, J.; Kushpil, V.; Lenkeit, B.; Ludolphs, W.; Maas, A.; Marn, A.; Milosevic, J.; Milov, A.; Miskowiec, D.; Panebrattsev, Yu.; Petchenova, O.; Petracek, V.; Pfeiffer, A.; Rak, J.; Ravinovich, I.; Rehak, P.; Schmitz, W.; Schukraft, J.; Sedykh, S.; Shimansky, S.; Slvova, J.; Stachel, J.; Sumbera, M.; Tilsner, H.; Tserruya, Itzhak; Wessels, J.P.; Wienold, T.; Windelband, B.; Wurm, J.P.; Xie, W.; Yurevich, S.; Yurevich, V.; Appelshauser, Harald; Sako, Hiro
2005-01-01
Results on event-by-event fluctuations of the mean transverse momentum and net charge in Pb-Au collisions, measured by the CERES Collaboration at CERN-SPS, are presented. We discuss the centrality and beam energy dependence and compare our data to cascade calculations.
Shearfree cylindrical gravitational collapse
International Nuclear Information System (INIS)
Di Prisco, A.; Herrera, L.; MacCallum, M. A. H.; Santos, N. O.
2009-01-01
We consider diagonal cylindrically symmetric metrics, with an interior representing a general nonrotating fluid with anisotropic pressures. An exterior vacuum Einstein-Rosen spacetime is matched to this using Darmois matching conditions. We show that the matching conditions can be explicitly solved for the boundary values of metric components and their derivatives, either for the interior or exterior. Specializing to shearfree interiors, a static exterior can only be matched to a static interior, and the evolution in the nonstatic case is found to be given in general by an elliptic function of time. For a collapsing shearfree isotropic fluid, only a Robertson-Walker dust interior is possible, and we show that all such cases were included in Cocke's discussion. For these metrics, Nolan and Nolan have shown that the matching breaks down before collapse is complete, and Tod and Mena have shown that the spacetime is not asymptotically flat in the sense of Berger, Chrusciel, and Moncrief. The issues about energy that then arise are revisited, and it is shown that the exterior is not in an intrinsic gravitational or superenergy radiative state at the boundary.
Quantum biological gravitational wave detectors
International Nuclear Information System (INIS)
Kopvillem, U.Kh.
1985-01-01
A possibility of producing biological detectors of gravitational waves is considered. High sensitivity of biological systems to outer effects can be ensured by existence of molecule subgroups in Dicke states. Existence of clusters in Dicke state-giant electric dipoles (GED) is supposed in the Froehlich theory. Comparison of biological and physical detectors shows that GED systems have unique properties for detection of gravitational waves if the reception range is narrow
General relativity and gravitation, 1989
International Nuclear Information System (INIS)
Ashby, N.; Bartlett, D.F.; Wyss, W.
1990-01-01
This volume records the lectures and symposia of the 12th International Conference on General Relativity and Gravitation. Plenary lecturers reviewed the major advances since the previous conference in 1986. The reviews cover classical and quantum theory of gravity, colliding gravitational waves, gravitational lensing, relativistic effects on pulsars, tests of the inverse square law, numerical relativity, cosmic microwave background radiation, experimental tests of gravity theory, gravitational wave detectors, and cosmology. The plenary lectures are complemented by summaries of symposia, provided by the chairmen. Almost 700 contributed papers were presented at these and they cover an even wider range of topics than the plenary talks. The book provides a comprehensive guide to research activity in both experimental and theoretical gravitation and its applications in astrophysics and cosmology. It will be essential reading for research workers in these fields, as well as theoretical and experimental physicists, astronomers, and mathematicians who wish to be acquainted with modern developments in gravitational theory and general relativity. All the papers and summaries of the workshop sessions are indexed separately. (16 united talks, 20 workshop sessions). (author)
Nuclear Quantum Gravitation - The Correct Theory
Kotas, Ronald
2016-03-01
Nuclear Quantum Gravitation provides a clear, definitive Scientific explanation of Gravity and Gravitation. It is harmonious with Newtonian and Quantum Mechanics, and with distinct Scientific Logic. Nuclear Quantum Gravitation has 10 certain, Scientific proofs and 21 more good indications. With this theory the Physical Forces are obviously Unified. See: OBSCURANTISM ON EINSTEIN GRAVITATION? http://www.santilli- Foundation.org/inconsistencies-gravitation.php and Einstein's Theory of Relativity versus Classical Mechanics http://www.newtonphysics.on.ca/einstein/
Einstein's Symphony: A Gravitational Wave Voyage Through Space and Time
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).
Collaboration and E-collaboration
DEFF Research Database (Denmark)
Razmerita, Liana; Kirchner, Kathrin
2015-01-01
Understanding student’s perception of collaboration and how collaboration is supported by ICT is important for its efficient use in the classroom. This article aims to investigate how students perceive collaboration and how they use new technologies in collaborative group work. Furthermore......, it tries to measure the impact of technology on students’ satisfaction with collaboration outcomes. In particular, the study aims to address the following research questions: Which demographic information (e.g. gender and place of origin) is significant for collaboration and ecollaboration? and Which...... are the perceived factors that influence the students’ group performance? The findings of this study emphasize that there are gender and cultural differences with respect to the perception of e-collaboration. Furthermore, the article summarizes in a model the most significant factors influencing group performance....
Causal properties of nonlinear gravitational waves in modified gravity
Suvorov, Arthur George; Melatos, Andrew
2017-09-01
Some exact, nonlinear, vacuum gravitational wave solutions are derived for certain polynomial f (R ) gravities. We show that the boundaries of the gravitational domain of dependence, associated with events in polynomial f (R ) gravity, are not null as they are in general relativity. The implication is that electromagnetic and gravitational causality separate into distinct notions in modified gravity, which may have observable astrophysical consequences. The linear theory predicts that tachyonic instabilities occur, when the quadratic coefficient a2 of the Taylor expansion of f (R ) is negative, while the exact, nonlinear, cylindrical wave solutions presented here can be superluminal for all values of a2. Anisotropic solutions are found, whose wave fronts trace out time- or spacelike hypersurfaces with complicated geometric properties. We show that the solutions exist in f (R ) theories that are consistent with Solar System and pulsar timing experiments.
The Virgo gravitational wave interferometer: status and perspectives
CERN. Geneva
2018-01-01
The first recording of a signal from a binary neutron star system by the Advanced LIGO and Advanced Virgo interferometers, and the observation of its remnants by telescopes in all bands of the electromagnetic spectrum, marked the beginning of multimessenger astronomy with gravitational waves. This followed the detection of gravitational wave signals by the LIGO interferometers in 2015, which started the detailed study of highly curved space time. These achievements come after decades of work spent understanding how to measure the tiny space time strain (h ~ 10-21) carried by gravitational waves. In the future, detectors will able to extract much more precise information from these events, or record signals from fainter sources, providing a new view of the Universe. After a presentation of the Virgo interferometer, the main results obtained from binary black hole and neutron star detection are reviewed. The focus will then shift on the perspective offered by a further reduction of noise in ground based interf...
DEFF Research Database (Denmark)
Mortensen, Thomas Bøtker
-Doerr, 1996) and has been shown to have a positive effect to the outcome of collaborative R&D (Sampson, 2005). Anand & Khanna (2000), furthermore, hypothesized that research joint ventures are more ambiguous than marketing joint ventures and even more the licensing and showed that the effect of collaborative......Literature review: Collaborative experience has been shown to have a positive effect on the collaborative outcome in general (Anand & Khanna, 2000; Kale, Dyer & Singh, 2002). Furthermore, it has been linked to the ability to exploit the network of the firm for learning (Powell, Koput and Smith...... experience was largest the higher the hypothesized ambiguity. Theoretically contribution: This research project aims at contributing to existing literature by arguing, that collaborative experience is a moderating variable which moderates the effects on collaborative outcome from the level of complexity...
Education and Strategic Research Collaborations
Los Alamos National Laboratory National Security Education Center Image Search Site submit LaboratoryNational Security Education Center Menu Program Offices Energy Security Council New Mexico Consortium Geophysics, Planetary Physics, Signatures Events Collaborations for education and strategic research, student
Strong lensing of gravitational waves as seen by LISA.
Sereno, M; Sesana, A; Bleuler, A; Jetzer, Ph; Volonteri, M; Begelman, M C
2010-12-17
We discuss strong gravitational lensing of gravitational waves from the merging of massive black hole binaries in the context of the LISA mission. Detection of multiple events would provide invaluable information on competing theories of gravity, evolution and formation of structures and, possibly, constraints on H0 and other cosmological parameters. Most of the optical depth for lensing is provided by intervening massive galactic halos, for which wave optics effects are negligible. Probabilities to observe multiple events are sizable for a broad range of formation histories. For the most optimistic models, up to ≲ 4 multiple events with a signal to noise ratio ≳ 8 are expected in a 5-year mission. Chances are significant even for conservative models with either light (≲ 60%) or heavy (≲ 40%) seeds. Because of lensing amplification, some intrinsically too faint signals are brought over threshold (≲ 2 per year).
Astronomers Discover Six-Image Gravitational Lens
2001-08-01
-Smithsonian Center for Astrophysics (CfA). "When we understand this system, we will have a much clearer picture of how galaxies are changed by being part of a bigger cluster of galaxies," he added. B1359+154 was discovered in 1999 by the Cosmic Lens All-Sky Survey, an international collaboration of astronomers who use radio telescopes to search the sky for gravitational lenses. Images made by the NSF's Very Large Array in New Mexico and by Britain's MERLIN radio telescope showed six objects suspected of being gravitational-lens images, but the results were inconclusive. Rusin and his team used the VLBA and HST in 1999 and 2000 to make more-detailed studies of B1359+154. The combination of data from the VLBA and HST convinced the astronomers that B1359+154 actually consists of six lensed images of a single background galaxy. The VLBA images were made from data collected during observations at a radio frequency of 1.7 GHz. "This is a great example of modern, multi-wavelength astronomy," said Rusin. "We need the radio telescopes to detect the gravitational lenses in the first place, then we need the visible-light information from Hubble to show us additional detail about the structure of the system." Armed with the combined VLBA and HST data about the positions and brightnesses of the six images of the background galaxy as well as the positions of the three intermediate galaxies, the astronomers did computer simulations to show how the gravitation of the three galaxies could produce the lens effect. They were able to design a computer model of the system that, in fact, produces the six images seen in B1359+154. "Our computer model certainly is not perfect, and we need to do more observations of this system to refine it, but we have clearly demonstrated that the three galaxies we see can produce a six-image lens system," said Martin Norbury, a graduate student at Jodrell Bank Observatory in Britain. "We think this work will give us an excellent tool for studying much-denser clusters of
Energy Technology Data Exchange (ETDEWEB)
Derue, Frederic [Paris-11 Univ., 91 Orsay (France)
1999-04-15
The EROS II experiment is searching for microlensing events due to compact massive objects passing through the line-of-sight of luminous stars. These objects are candidates to explain the baryonic component of Dark Matter in our Galaxy. EROS II was dedicated to different lines-of-sight: Small and Large Magellanic Clouds, Galactic Centre and 4 directions towards the Spiral Arms of the Galaxy. This thesis presents the first search for microlensing towards these last lines-of-sight (about 9 million stars). Simple criteria based on the search for significant fluctuations allowed one to discover a low noise sample of 7 candidates to the microlensing effect, with an average timescale of 50 days. A detailed analysis of the light curve of one candidate allows us to give a confidence interval on its mass 2.7 x 10{sup -3} < M/M{sub 0} < 0.84 at 95% CL. The amplification curve of another candidate shows a modulation which can be interpreted as a microlensing effect acting on a binary source, with an orbital period of P{sub 0} = 50 {+-} 3 days. To improve the knowledge of the distance of the target stars, we have combined observations of EROS II with bibliographic sources on associations of stars linked with the spiral arm features, and we have developed a program to find variable stars. Ten cepheids have thus been found. Distances obtained with different methods are in rough agreement with each other. The average optical depth measured towards the four directions is {tau}-bar = 0.45{sub 0.11}{sup +0.23} x 10{sup -6}. It is compatible with expectations from simple galactic models. The long duration of most events favours interpretation of lensing by objects belonging to the disk instead of the halo. It also seems that some events due to bulge lenses have influenced measurements towards the line-of-sight which is closest to the Galactic Centre. Observation continue towards spiral arms. More accurate measurements should be obtained with increase of statistics, allowing one to
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; 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2016-02-12
On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0×10(-21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203,000 years, equivalent to a significance greater than 5.1σ. The source lies at a luminosity distance of 410(-180)(+160) Mpc corresponding to a redshift z=0.09(-0.04)(+0.03). In the source frame, the initial black hole masses are 36(-4)(+5)M⊙ and 29(-4)(+4)M⊙, and the final black hole mass is 62(-4)(+4)M⊙, with 3.0(-0.5)(+0.5)M⊙c(2) radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.
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.; Camp, Jordan B.;
2016-01-01
On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal. The signal sweeps upwards in frequency from 35 to 250 Hz with a peak gravitational-wave strain of 1.0 x 10(exp -21). It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ring down of the resulting single black hole. The signal was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1 Sigma. The source lies at a luminosity distance of 410(+160/-180) Mpc corresponding to a redshift z = 0.09(+0.03/-0.04). In the source frame, the initial black hole masses are 36(+5/-4) Mass compared to the sun, and 29(+4/-4) Mass compared to the sun, and the final black hole mass is 62(+4/-4) Mass compared to the sun, with 3.0(+0.5/-0.5)sq c radiated in gravitational waves. All uncertainties define 90% credible intervals. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.
Low-Frequency Gravitational Wave Searches Using Spacecraft Doppler Tracking
Directory of Open Access Journals (Sweden)
Armstrong J. W.
2006-01-01
Full Text Available This paper discusses spacecraft Doppler tracking, the current-generation detector technology used in the low-frequency (~millihertz gravitational wave band. In the Doppler method the earth and a distant spacecraft act as free test masses with a ground-based precision Doppler tracking system continuously monitoring the earth-spacecraft relative dimensionless velocity $2 Delta v/c = Delta u/ u_0$, where $Delta u$ is the Doppler shift and $ u_0$ is the radio link carrier frequency. A gravitational wave having strain amplitude $h$ incident on the earth-spacecraft system causes perturbations of order $h$ in the time series of $Delta u/ u_0$. Unlike other detectors, the ~1-10 AU earth-spacecraft separation makes the detector large compared with millihertz-band gravitational wavelengths, and thus times-of-flight of signals and radio waves through the apparatus are important. A burst signal, for example, is time-resolved into a characteristic signature: three discrete events in the Doppler time series. I discuss here the principles of operation of this detector (emphasizing transfer functions of gravitational wave signals and the principal noises to the Doppler time series, some data analysis techniques, experiments to date, and illustrations of sensitivity and current detector performance. I conclude with a discussion of how gravitational wave sensitivity can be improved in the low-frequency band.
A new geometrical gravitational theory
International Nuclear Information System (INIS)
Obata, T.; Chiba, J.; Oshima, H.
1981-01-01
A geometrical gravitational theory is developed. The field equations are uniquely determined apart from one unknown dimensionless parameter ω 2 . It is based on an extension of the Weyl geometry, and by the extension the gravitational coupling constant and the gravitational mass are made to be dynamical and geometrical. The fundamental geometrical objects in the theory are a metric gsub(μν) and two gauge scalars phi and psi. The theory satisfies the weak equivalence principle, but breaks the strong one generally. u(phi, psi) = phi is found out on the assumption that the strong one keeps holding good at least for bosons of low spins. Thus there is the simple correspondence between the geometrical objects and the gravitational objects. Since the theory satisfies the weak one, the inertial mass is also dynamical and geometrical in the same way as is the gravitational mass. Moreover, the cosmological term in the theory is a coscalar of power -4 algebraically made of psi and u(phi, psi), so it is dynamical, too. Finally spherically symmetric exact solutions are given. The permissible range of the unknown parameter ω 2 is experimentally determined by applying the solutions to the solar system. (author)
Modified entropic gravitation in superconductors
International Nuclear Information System (INIS)
Matos, Clovis Jacinto de
2012-01-01
Verlinde recently developed a theoretical account of gravitation in terms of an entropic force. The central element in Verlinde’s derivation is information and its relation with entropy through the holographic principle. The application of this approach to the case of superconductors requires to take into account that information associated with superconductor’s quantum vacuum energy is not stored on Planck size surface elements, but in four volume cells with Planck-Einstein size. This has profound consequences on the type of gravitational force generated by the quantum vacuum condensate in superconductors, which is closely related with the cosmological repulsive acceleration responsible for the accelerated expansion of the Universe. Remarkably this new gravitational type force depends on the level of breaking of the weak equivalence principle for cooper pairs in a given superconducting material, which was previously derived by the author starting from similar principles. It is also shown that this new gravitational force can be interpreted as a surface force. The experimental detection of this new repulsive gravitational-type force appears to be challenging.
Gravitational waves from supernova matter
International Nuclear Information System (INIS)
Scheidegger, S; Whitehouse, S C; Kaeppeli, R; Liebendoerfer, M
2010-01-01
We have performed a set of 11 three-dimensional magnetohydrodynamical (MHD) core-collapse supernova simulations in order to investigate the dependences of the gravitational wave signal on the progenitor's initial conditions. We study the effects of the initial central angular velocity and different variants of neutrino transport. Our models are started up from a 15M o-dot progenitor and incorporate an effective general relativistic gravitational potential and a finite temperature nuclear equation of state. Furthermore, the electron flavour neutrino transport is tracked by efficient algorithms for the radiative transfer of massless fermions. We find that non- and slowly rotating models show gravitational wave emission due to prompt- and lepton driven convection that reveals details about the hydrodynamical state of the fluid inside the protoneutron stars. Furthermore we show that protoneutron stars can become dynamically unstable to rotational instabilities at T/|W| values as low as ∼2% at core bounce. We point out that the inclusion of deleptonization during the postbounce phase is very important for the quantitative gravitational wave (GW) prediction, as it enhances the absolute values of the gravitational wave trains up to a factor of ten with respect to a lepton-conserving treatment.
Relic gravitational waves and cosmology
International Nuclear Information System (INIS)
Grishchuk, Leonid P
2005-01-01
The paper begins with a brief recollection of interactions of the author with Ya B Zeldovich in the context of the study of relic gravitational waves. The principles and early results on the quantum-mechanical generation of cosmological perturbations are then summarized. The expected amplitudes of relic gravitational waves differ in various frequency windows, and therefore the techniques and prospects of their detection are distinct. One section of the paper describes the present state of efforts in direct detection of relic gravitational waves. Another section is devoted to indirect detection via the anisotropy and polarization measurements of the cosmic microwave background (CMB) radiation. It is emphasized throughout the paper that the inference about the existence and expected amount of relic gravitational waves is based on a solid theoretical foundation and the best available cosmological observations. It is also explained in great detail what went wrong with the so-called 'inflationary gravitational waves', whose amount is predicted by inflationary theorists to be negligibly small, thus depriving them of any observational significance. (reviews of topical problems)
Maris, Mariann
The University of Wisconsin-Milwaukee writing program is collaborative, not divisionary, as some, such as Jeanne Gunner, have suggested. Three terms are useful in understanding the relationships and ethics governing operations at Wisconsin-Milwaukee: (1) authority and collaboration; (2) hierarchical difference; (3) professional respect.…
CAN THE MASSES OF ISOLATED PLANETARY-MASS GRAVITATIONAL LENSES BE MEASURED BY TERRESTRIAL PARALLAX?
Energy Technology Data Exchange (ETDEWEB)
Freeman, M.; Botzler, C. S.; Bray, J. C.; Cherrie, J. M.; Rattenbury, N. J. [Department of Physics, University of Auckland, Private Bag 92019, Auckland 1142 (New Zealand); Philpott, L. C. [Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4 (Canada); Abe, F.; Muraki, Y. [Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya 464-8601 (Japan); Albrow, M. D. [Department of Physics and Astronomy, University of Canterbury, P.O. Box 4800, Christchurch 8020 (New Zealand); Bennett, D. P. [Department of Physics, 225 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556 (United States); Bond, I. A. [Institute for Information and Mathematical Sciences, Massey University, Private Bag 102-904, Auckland 1330 (New Zealand); Christie, G. W.; Natusch, T. [Auckland Observatory, PO Box 180, Royal Oak, Auckland 1345 (New Zealand); Dionnet, Z. [Université d' Orsay, bat 470, F-91400 Orsay (France); Gould, A. [Department of Astronomy, Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Han, C. [Department of Physics, Chungbuk National University, 410 Seongbong-Rho, Hungduk-Gu, Chongju 371-763 (Korea, Republic of); Heyrovský, D. [Institute of Theoretical Physics, Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague (Czech Republic); McCormick, J. M. [Farm Cove Observatory, 2/24 Rapallo Place, Pakuranga, Auckland 2012 (New Zealand); Moorhouse, D. M. [Kumeu Observatory, Kumeu (New Zealand); Skowron, J., E-mail: mfre070@aucklanduni.ac.nz [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478, Warszawa (Poland); and others
2015-02-01
Recently Sumi et al. reported evidence for a large population of planetary-mass objects (PMOs) that are either unbound or orbit host stars in orbits ≥10 AU. Their result was deduced from the statistical distribution of durations of gravitational microlensing events observed by the MOA collaboration during 2006 and 2007. Here we study the feasibility of measuring the mass of an individual PMO through microlensing by examining a particular event, MOA-2011-BLG-274. This event was unusual as the duration was short, the magnification high, the source-size effect large, and the angular Einstein radius small. Also, it was intensively monitored from widely separated locations under clear skies at low air masses. Choi et al. concluded that the lens of the event may have been a PMO but they did not attempt a measurement of its mass. We report here a re-analysis of the event using re-reduced data. We confirm the results of Choi et al. and attempt a measurement of the mass and distance of the lens using the terrestrial parallax effect. Evidence for terrestrial parallax is found at a 3σ level of confidence. The best fit to the data yields the mass and distance of the lens as 0.80 ± 0.30 M {sub J} and 0.80 ± 0.25 kpc respectively. We exclude a host star to the lens out to a separation ∼40 AU. Drawing on our analysis of MOA-2011-BLG-274 we propose observational strategies for future microlensing surveys to yield sharper results on PMOs including those down to super-Earth mass.
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.
DEFF Research Database (Denmark)
Bogers, Marcel; Horst, Willem
2014-01-01
of the prototyping process, the actual prototype was used as a tool for communication or development, thus serving as a platform for the cross-fertilization of knowledge. In this way, collaborative prototyping leads to a better balance between functionality and usability; it translates usability problems into design......This paper presents an inductive study that shows how collaborative prototyping across functional, hierarchical, and organizational boundaries can improve the overall prototyping process. Our combined action research and case study approach provides new insights into how collaborative prototyping...... can provide a platform for prototype-driven problem solving in early new product development (NPD). Our findings have important implications for how to facilitate multistakeholder collaboration in prototyping and problem solving, and more generally for how to organize collaborative and open innovation...
Engaging the public in the nascent era of gravitational-wave astronomy
Hendry, Martin A.
2015-08-01
Within the next few years a global network of ground-based laser interferometers will become fully operational. These ultra-sensitive instruments are confidently expected to directly detect gravitational waves from astrophysical sources before the end of the decade. In anticipation of opening this entirely new window on the Universe, the LIGO (Laser Interferometer Gravitational Wave Observatory) Scientific Collaboration has recently developed a substantive program of education and public outreach activities that includes exhibitions, documentary films, social media and interactive games - as well as more traditional modes of science communication such as schools and public lectures.As the gravitational wave 'detection era' unfolds over the next decade, it will present exciting challenges for future public engagement by the LIGO Scientific Collaboration and by other gravitational-wave astronomy collaborations around the world. Perhaps the most interesting opportunities will be in the area of citizen science, building upon the infrastructure already being developed through e.g. the LIGO Open Science Center (see arXiv:1410.4839) and the remarkable success of the Einstein@Home project (www.einsteinathome.org).In this presentation I will give an overview of the LSC education and public outreach program, highlighting its goals, major successes and future strategy - particularly in relation to the release of future LIGO and other gravitational wave datasets to the scientific community and to the public, and the opportunities this will present for directly engaging citizen scientists in this exciting new field of observational astronomy.
Chirality and gravitational parity violation.
Bargueño, Pedro
2015-06-01
In this review, parity-violating gravitational potentials are presented as possible sources of both true and false chirality. In particular, whereas phenomenological long-range spin-dependent gravitational potentials contain both truly and falsely chiral terms, it is shown that there are models that extend general relativity including also coupling of fermionic degrees of freedom to gravity in the presence of torsion, which give place to short-range truly chiral interactions similar to that usually considered in molecular physics. Physical mechanisms which give place to gravitational parity violation together with the expected size of the effects and their experimental constraints are discussed. Finally, the possible role of parity-violating gravity in the origin of homochirality and a road map for future research works in quantum chemistry is presented. © 2015 Wiley Periodicals, Inc.
Post-Newtonian gravitational bremsstrahlung
International Nuclear Information System (INIS)
Turner, M.; Will, C.M.
1978-01-01
We present formulae and numerical results for the gravitational radiation emitted during a low-deflection encounter between two massive bodies (''gravitational bremsstrahlung''). Our results are valid through post-Newtonian order within general relativity. We discuss in detail the gravitational waveform (transverse-traceless part of the metric perturbation tensor), the toal luminosity and total emitted energy, the angular distribution of emitted energy (antenna pattern), and the frequency spectrum. We also present a method of ''boosting'' the accuracy of these quantities to post-3/2-Newtonian order. A numerical comparison of our results with those of Peters and of Kovacs and Thorne shows that the post-Newtonian method is reliable to better than 0.1% at v=0.1c, to a few percent at v=0.35c, and to 10--20% at v=0.5c. We also compare our results with those of Smarr
Sparse representation of Gravitational Sound
Rebollo-Neira, Laura; Plastino, A.
2018-03-01
Gravitational Sound clips produced by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Massachusetts Institute of Technology (MIT) are considered within the particular context of data reduction. We advance a procedure to this effect and show that these types of signals can be approximated with high quality using significantly fewer elementary components than those required within the standard orthogonal basis framework. Furthermore, a local measure sparsity is shown to render meaningful information about the variation of a signal along time, by generating a set of local sparsity values which is much smaller than the dimension of the signal. This point is further illustrated by recourse to a more complex signal, generated by Milde Science Communication to divulge Gravitational Sound in the form of a ring tone.
Gravitational Waves and Dark Energy
Directory of Open Access Journals (Sweden)
Peter L. Biermann
2014-12-01
Full Text Available The idea that dark energy is gravitational waves may explain its strength and its time-evolution. A possible concept is that dark energy is the ensemble of coherent bursts (solitons of gravitational waves originally produced when the first generation of super-massive black holes was formed. These solitons get their initial energy as well as keep up their energy density throughout the evolution of the universe by stimulating emission from a background, a process which we model by working out this energy transfer in a Boltzmann equation approach. New Planck data suggest that dark energy has increased in strength over cosmic time, supporting the concept here. The transit of these gravitational wave solitons may be detectable. Key tests include pulsar timing, clock jitter and the radio background.
Gravitational-wave mediated preheating
Energy Technology Data Exchange (ETDEWEB)
Alexander, Stephon [Center for Cosmic Origins and Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Cormack, Sam, E-mail: samuel.c.cormack.gr@dartmouth.edu [Center for Cosmic Origins and Department of Physics and Astronomy, Dartmouth College, Hanover, NH 03755 (United States); Marcianò, Antonino [Center for Field Theory and Particle Physics & Department of Physics, Fudan University, 200433 Shanghai (China); Yunes, Nicolás [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Kavli Institute for Theoretical Physics, University of California, Santa Barbara, CA 93106 (United States)
2015-04-09
We propose a new preheating mechanism through the coupling of the gravitational field to both the inflaton and matter fields, without direct inflaton–matter couplings. The inflaton transfers power to the matter fields through interactions with gravitational waves, which are exponentially enhanced due to an inflation–graviton coupling. One such coupling is the product of the inflaton to the Pontryagin density, as in dynamical Chern–Simons gravity. The energy scales involved are constrained by requiring that preheating happens fast during matter domination.
Testing the gravitational instability hypothesis?
Babul, Arif; Weinberg, David H.; Dekel, Avishai; Ostriker, Jeremiah P.
1994-01-01
We challenge a widely accepted assumption of observational cosmology: that successful reconstruction of observed galaxy density fields from measured galaxy velocity fields (or vice versa), using the methods of gravitational instability theory, implies that the observed large-scale structures and large-scale flows were produced by the action of gravity. This assumption is false, in that there exist nongravitational theories that pass the reconstruction tests and gravitational theories with certain forms of biased galaxy formation that fail them. Gravitational instability theory predicts specific correlations between large-scale velocity and mass density fields, but the same correlations arise in any model where (a) structures in the galaxy distribution grow from homogeneous initial conditions in a way that satisfies the continuity equation, and (b) the present-day velocity field is irrotational and proportional to the time-averaged velocity field. We demonstrate these assertions using analytical arguments and N-body simulations. If large-scale structure is formed by gravitational instability, then the ratio of the galaxy density contrast to the divergence of the velocity field yields an estimate of the density parameter Omega (or, more generally, an estimate of beta identically equal to Omega(exp 0.6)/b, where b is an assumed constant of proportionality between galaxy and mass density fluctuations. In nongravitational scenarios, the values of Omega or beta estimated in this way may fail to represent the true cosmological values. However, even if nongravitational forces initiate and shape the growth of structure, gravitationally induced accelerations can dominate the velocity field at late times, long after the action of any nongravitational impulses. The estimated beta approaches the true value in such cases, and in our numerical simulations the estimated beta values are reasonably accurate for both gravitational and nongravitational models. Reconstruction tests
Linear interaction of gravitational waves
International Nuclear Information System (INIS)
Ciubotariu, C.D.
1992-01-01
Starting with the linearized Einstein equations written in the same form as Maxwell equations, a damping term is found in the wave equation. The analogy with the propagation of the electromagnetic wave in ohmic media is obvious if we introduce an 'ohmic relation' for gravitational interaction. The possibility of the amplification of gravitational waves by a suitable choice of the velocity field of a dust ('dust with negative viscosity'), for example by the use of the free-electron laser principle, is indicated. (Author)
Gravitational Anomaly and Transport Phenomena
International Nuclear Information System (INIS)
Landsteiner, Karl; Megias, Eugenio; Pena-Benitez, Francisco
2011-01-01
Quantum anomalies give rise to new transport phenomena. In particular, a magnetic field can induce an anomalous current via the chiral magnetic effect and a vortex in the relativistic fluid can also induce a current via the chiral vortical effect. The related transport coefficients can be calculated via Kubo formulas. We evaluate the Kubo formula for the anomalous vortical conductivity at weak coupling and show that it receives contributions proportional to the gravitational anomaly coefficient. The gravitational anomaly gives rise to an anomalous vortical effect even for an uncharged fluid.
General relativity and gravitational waves
Weber, Johanna
1961-01-01
An internationally famous physicist and electrical engineer, the author of this text was a pioneer in the investigation of gravitational waves. Joseph Weber's General Relativity and Gravitational Waves offers a classic treatment of the subject. Appropriate for upper-level undergraduates and graduate students, this text remains ever relevant. Brief but thorough in its introduction to the foundations of general relativity, it also examines the elements of Riemannian geometry and tensor calculus applicable to this field.Approximately a quarter of the contents explores theoretical and experimenta
The 'gravitating' tensor in the dualistic theory
International Nuclear Information System (INIS)
Mahanta, M.N.
1989-01-01
The exact microscopic system of Einstein-type field equations of the dualistic gravitation theory is investigated as well as an analysis of the modified energy-momentum tensor or so called 'gravitating' tensor is presented
The Theory of Vortical Gravitational Fields
Directory of Open Access Journals (Sweden)
Rabounski D.
2007-04-01
Full Text Available This paper treats of vortical gravitational fields, a tensor of which is the rotor of the general covariant gravitational inertial force. The field equations for a vortical gravitational field (the Lorentz condition, the Maxwell-like equations, and the continuity equation are deduced in an analogous fashion to electrodynamics. From the equations it is concluded that the main kind of vortical gravitational fields is “electric”, determined by the non-stationarity of the acting gravitational inertial force. Such a field is a medium for traveling waves of the force (they are different to the weak deformation waves of the space metric considered in the theory of gravitational waves. Standing waves of the gravitational inertial force and their medium, a vortical gravitational field of the “magnetic” kind, are exotic, since a non-stationary rotation of a space body (the source of such a field is a very rare phenomenon in the Universe.
Merging Black Holes and Gravitational Waves
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.
Discovery of two new gravitation lens systems
International Nuclear Information System (INIS)
Guertler, J.
1988-01-01
The discovery of new quasar and radio galaxy double images produced by the gravitation lens effect is reported. The light deflecting galaxies acting as gravitational lenses could be made visible by means of image processing procedures
Parametric mechanisms for detecting gravitational waves
International Nuclear Information System (INIS)
Pustovoit, V.I.; Chernozatonskii, L.A.
1981-01-01
An intense electromagnetic wave and a gravitational wave can interact to effectively generate electromagnetic waves at sum and difference frequencies. The self-effect of a monochromatic electromagnetic wave through a gravitational field leads to third-harmonic generation
Resonant-bar gravitational radiation antennas
International Nuclear Information System (INIS)
Blair, D.G.
1987-01-01
This paper reviews the concept of gravitational radiation, and describes the worldwide research programme for the development of high-sensitivity resonant-bar antennas which are aimed at detecting gravitational radiation from astrophysical sources. (author)
Gravitational wave: gamma-ray burst connections.
Hough, Jim
2007-05-15
After 35 years of experimental research, we are rapidly approaching the point at which gravitational waves (GWs) from astrophysical sources may be directly detected by the long-baseline detectors LIGO (USA), GEO 600 (Germany/UK), VIRGO (Italy/France) and TAMA 300 (Japan), which are now in or coming into operation.A promising source of GWs is the coalescence of compact binary systems, events which are now believed to be the origin of short gamma-ray bursts (GRBs). In this paper, a brief review of the state of the art in detector development and exploitation will be given, with particular relevance to a search for signals associated with GRBs, and plans for the future will be discussed.
Coherent network detection of gravitational waves: the redundancy veto
International Nuclear Information System (INIS)
Wen Linqing; Schutz, Bernard F
2005-01-01
A network of gravitational wave detectors is called redundant if, given the direction to a source, the strain induced by a gravitational wave in one or more of the detectors can be fully expressed in terms of the strain induced in others in the network. Because gravitational waves have only two polarizations, any network of three or more differently oriented interferometers with similar observing bands is redundant. The three-armed LISA space interferometer has three outputs that are redundant at low frequencies. The two aligned LIGO interferometers at Hanford WA are redundant, and the LIGO detector at Livingston LA is nearly redundant with either of the Hanford detectors. Redundant networks have a powerful veto against spurious noise, a linear combination of the detector outputs that contains no gravitational wave signal. For LISA, this 'null' output is known as the Sagnac mode, and its use in discriminating between detector noise and a cosmological gravitational wave background is well understood. But the usefulness of the null veto for ground-based detector networks has been ignored until now. We show that it should make it possible to discriminate in a model-independent way between real gravitational waves and accidentally coincident non-Gaussian noise 'events' in redundant networks of two or more broadband detectors. It has been shown that with three detectors, the null output can even be used to locate the direction to the source, and then two other linear combinations of detector outputs give the optimal 'coherent' reconstruction of the two polarization components of the signal. We discuss briefly the implementation of such a detection strategy in realistic networks, where signals are weak, detector calibration is a significant uncertainty, and the various detectors may have different (but overlapping) observing bands
Gravitational states of antihydrogen near material surface
Energy Technology Data Exchange (ETDEWEB)
Voronin, Alexei Yu., E-mail: dr.a.voronin@gmail.com [P.N. Lebedev Physical Institute (Russian Federation); Froelich, Piotr [Uppsala University, Department of Quantum Chemistry (Sweden); Nesvizhevsky, Valery V. [Institut Laue-Langevin (ILL) (France)
2012-12-15
We present a theoretical study of the motion of antihydrogen atoms in the Earth's gravitational field near a material surface. We predict the existence of long-living quasistationary states of antihydrogen in a superposition of the gravitational and Casimir-van der Waals potentials of the surface. We suggest an interferometric method of measuring the energy difference between such gravitational states, hence the gravitational mass of antihydrogen.
Gravitational wave reception by a sphere
International Nuclear Information System (INIS)
Ashby, N.; Dreitlein, J.
1975-01-01
The reception of gravitational waves by an elastic self-gravitating spherical detector is studied in detail. The equations of motion of a detector driven by a gravitational wave are presented in the intuitively convenient coordinate system of Fermi. An exact analytic solution is given for the homogeneous isotropic sphere. Nonlinear effects of a massive self-gravitating system are computed for a body of mass equal to that of the earth, and are shown to be numerically important
Vector-tensor interaction of gravitation
Energy Technology Data Exchange (ETDEWEB)
Zhang Yuan-zhong; Guo han-ying
1982-11-01
In the paper, by using the equation of motion a particle, we show that the antigravity exist in the vector-tensor model of gravitation. Thus the motion of a particle deviates from the geodesic equation. In Newtonian approximation and weak gravitational field, acceleration of a particle in a spherically symmetric and astatic gravitation field is zero. The result is obviously not in agreement with gravitational phenomena.
The Japanese space gravitational wave antenna; DECIGO
Kawamura, Seiji; Ando, Masaki; Nakamura, Takashi; Tsubono, Kimio; Tanaka, Takahiro; Funaki, Ikkoh; Seto, Naoki; Numata, Kenji; Sato, Shuichi; Ioka, Kunihito; Kanda, Nobuyuki; Takashima, Takeshi; Agatsuma, Kazuhiro; Akutsu, Tomotada; Akutsu, Tomomi
2008-01-01
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. The goal of DECIGO is to detect gravitational waves from various kinds of sources mainly between 0.1 Hz and 10 Hz and thus to open a new window of observation for gravitational wave astronomy. DECIGO will consist of three drag-free spacecraft, 1000 km apart from each other, whose relative displacements are measured by a Fabry—Perot Michelson interferometer. We plan to lau...
The Japanese space gravitational wave antenna - DECIGO
Kawamura, Seiji; Ando, Masaki; Nakamura, Takashi; Tsubono, Kimio; Tanaka, Takahiro; Funaki, Iklkoh; Seto, Naoki; Numata, Kenji; Sato, Shuichi; Ioka, Kunihito; Kanda, Nobuyuki; Takashima, Takeshi; Agatsuma, Kazuhiro; Akutsu, Tomotada; Akutsu, Tomomi
2008-01-01
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. The goal of DECIGO is to detect gravitational waves from various kinds of sources mainly between 0.1 Hz and 10 Hz and thus to open a new window of observation for gravitational wave astronomy. DECIGO will consist of three drag-free spacecraft, 1000 km apart from each other, whose relative displacements are measured by a Fabry—Perot Michelson interferometer. We plan to lau...
Effect of the Earth's gravitational field on the detection of gravitational waves
International Nuclear Information System (INIS)
Denisov, V.I.; Eliseev, V.A.
1988-01-01
We consider the laboratory detection of high-frequency gravitational waves in theories of gravitation based on a pseudo-Euclidean space-time. We analyze the effects due to the Earth's gravitational field on the propagation velocities of gravitational and electromagnetic waves in these theories. Experiments to test the predictions of this class of theories are discussed
DEFF Research Database (Denmark)
Gjerdrum Pedersen, Esben Rahbek; Netter, Sarah
2015-01-01
Purpose – The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach – The analysis is based on a multiple-case study of Scandinavian fashion libraries – a new...... to the new phenomenon of fashion libraries and does not cover other types of collaborative consumption within the fashion industry (Swap-parties, etc.). Originality/value – The paper is one of the first attempts to examine new business models of collaborative consumption in general and the fashion library...... concept in particular. The study contributes to the discussions of whether and how fashion sharing and collaboration holds promise as a viable business model and as a means to promote sustainability....
DEFF Research Database (Denmark)
Gjerdrum Pedersen, Esben Rahbek; Netter, Sarah
Purpose: The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach: The analysis is based on a multiple-‐‑case study of Scandinavian fashion libraries – a new...... to the new phenomenon of fashion libraries and does not cover other types of collaborative consumption within the fashion industry (Swap-‐‑parties, etc.). Originality/value: The paper is one of the first attempts to examine new business models of collaborative consumption in general and the fashion library...... concept in particular. The study contributes to the discussions of whether and how fashion sharing and collaboration holds promise as a viable business model and as a means to promote sustainability....
Plausibility Arguments and Universal Gravitation
Cunha, Ricardo F. F.; Tort, A. C.
2017-01-01
Newton's law of universal gravitation underpins our understanding of the dynamics of the Solar System and of a good portion of the observable universe. Generally, in the classroom or in textbooks, the law is presented initially in a qualitative way and at some point during the exposition its mathematical formulation is written on the blackboard…
Scientific visualization of gravitational lenses
International Nuclear Information System (INIS)
Magallon, M.
1999-01-01
Concepts related to gravitational lenses are discussed and applied to develop an interactive visualization tool that allow us to investigate them. Optimization strategies were performed to elaborate the tool. Some results obtained from the application of the tool are shown [es
Wilson loops in Kerr gravitation
International Nuclear Information System (INIS)
Bollini, C.G.; Giambiagi, J.J.; Tiomno, J.
1981-01-01
The ordered integrals for several paths in Kerr gravitation is computed in a compact form. When the path is closed its relation with the angular parallel displacement is discussed and the corresponding Wilson loop is calculated. The validity of Mandelstam relations for gauge fields is also explicitly verified. (Author) [pt
Gravitational lensing in plasmic medium
Energy Technology Data Exchange (ETDEWEB)
Bisnovatyi-Kogan, G. S., E-mail: gkogan@iki.rssi.ru; Tsupko, O. Yu., E-mail: tsupko@iki.rssi.ru [Russian Academy of Sciences, Space Research Institute (Russian Federation)
2015-07-15
The influence of plasma on different effects of gravitational lensing is reviewed. Using the Hamiltonian approach for geometrical optics in a medium in the presence of gravity, an exact formula for the photon deflection angle by a black hole (or another body with a Schwarzschild metric) embedded in plasma with a spherically symmetric density distribution is derived. The deflection angle in this case is determined by the mutual combination of different factors: gravity, dispersion, and refraction. While the effects of deflection by the gravity in vacuum and the refractive deflection in a nonhomogeneous medium are well known, the new effect is that, in the case of a homogeneous plasma, in the absence of refractive deflection, the gravitational deflection differs from the vacuum deflection and depends on the photon frequency. In the presence of a plasma nonhomogeneity, the chromatic refractive deflection also occurs, so the presence of plasma always makes gravitational lensing chromatic. In particular, the presence of plasma leads to different angular positions of the same image if it is observed at different wavelengths. It is discussed in detail how to apply the presented formulas for the calculation of the deflection angle in different situations. Gravitational lensing in plasma beyond the weak deflection approximation is also considered.
Academic Training: Gravitational Waves Astronomy
2006-01-01
2006-2007 ACADEMIC TRAINING PROGRAMME LECTURE SERIES 16, 17, 18 October from 11:00 to 12:00 - Main Auditorium, bldg. 500 Gravitational Waves Astronomy M. LANDRY, LIGO Hanford Observatory, Richland, USA Gravitational wave astronomy is expected to become an observational field within the next decade. First direct detection of gravitational waves is possible with existing terrestrial-based detectors, and highly probable with proposed upgrades. In this three-part lecture series, we give an overview of the field, including material on gravitional wave sources, detection methods, some details of interferometric detectors, data analysis methods, and current results from observational data-taking runs of the LIGO and GEO projects.ENSEIGNEMENT ACADEMIQUE ACADEMIC TRAINING Françoise Benz 73127 academic.training@cern.ch If you wish to participate in one of the following courses, please tell to your supervisor and apply electronically from the course description pages that can be found on the Web at: http://www.cern...
Normalization of Gravitational Acceleration Models
Eckman, Randy A.; Brown, Aaron J.; Adamo, Daniel R.
2011-01-01
Unlike the uniform density spherical shell approximations of Newton, the con- sequence of spaceflight in the real universe is that gravitational fields are sensitive to the nonsphericity of their generating central bodies. The gravitational potential of a nonspherical central body is typically resolved using spherical harmonic approximations. However, attempting to directly calculate the spherical harmonic approximations results in at least two singularities which must be removed in order to generalize the method and solve for any possible orbit, including polar orbits. Three unique algorithms have been developed to eliminate these singularities by Samuel Pines [1], Bill Lear [2], and Robert Gottlieb [3]. This paper documents the methodical normalization of two1 of the three known formulations for singularity-free gravitational acceleration (namely, the Lear [2] and Gottlieb [3] algorithms) and formulates a general method for defining normalization parameters used to generate normalized Legendre Polynomials and ALFs for any algorithm. A treatment of the conventional formulation of the gravitational potential and acceleration is also provided, in addition to a brief overview of the philosophical differences between the three known singularity-free algorithms.
Intercultural Collaboration Stories
DEFF Research Database (Denmark)
Gertsen, Martine Cardel; Søderberg, Anne-Marie
2011-01-01
The objective of this article is to show how narrative methods provide useful tools for international business research. We do this by presenting a study of stories told about the collaboration between a Danish expatriate manager and his Chinese CEO in the Shanghai subsidiary of an MNE. First, we...... to elucidate intercultural collaboration processes by analyzing how each member of a dyad of interacting managers narrates the same chain of events. We show how the narratological concepts of peripeteia and anagnorisis are well suited to identifying focal points in their stories: situations where change...... follows their recognizing new dimensions of their conflicts, eventually furthering their collaboration. We explain how Greimas's actantial model is valuable when mapping differences between and changes in the narrators’ projects, alliances and oppositions in the course of their interaction. Thus, we make...
Spinor approach to gravitational motion and precession
International Nuclear Information System (INIS)
Hestenes, D.
1986-01-01
The translational and rotational equations of motion for a small rigid body in a gravitational field are combined in a single spinor equation. Besides its computational advantages, this unifies the description of gravitational interaction in classical and quantum theory. Explicit expressions for gravitational precession rates are derived. (author)
On black holes and gravitational waves
Loinger, Angelo
2002-01-01
Black holes and gravitational waves are theoretical entities of today astrophysics. Various observed phenomena have been associated with the concept of black hole ; until now, nobody has detected gravitational waves. The essays contained in this book aim at showing that the concept of black holes arises from a misinterpretation of general relativity and that gravitational waves cannot exist.
Detecting gravitational waves from accreting neutron stars
Watts, A.L.; Krishnan, B.
2009-01-01
The gravitational waves emitted by neutron stars carry unique information about their structure and composition. Direct detection of these gravitational waves, however, is a formidable technical challenge. In a recent study we quantified the hurdles facing searches for gravitational waves from the
Optimal Search for an Astrophysical Gravitational-Wave Background
Rory Smith; Eric Thrane
2018-01-01
Roughly every 2–10 min, a pair of stellar-mass black holes merge somewhere in the Universe. A small fraction of these mergers are detected as individually resolvable gravitational-wave events by advanced detectors such as LIGO and Virgo. The rest contribute to a stochastic background. We derive the statistically optimal search strategy (producing minimum credible intervals) for a background of unresolved binaries. Our method applies Bayesian parameter estimation to all available data. Using M...
Search for gravitational waves from binary black hole inspirals in LIGO data
International Nuclear Information System (INIS)
Abbott, B.; Abbott, R.; Adhikari, R.; Agresti, J.; Anderson, S.B.; Araya, M.; Armandula, H.; Asiri, F.; Barish, B.C.; Barnes, M.; Barton, M.A.; Bhawal, B.; Billingsley, G.; Black, E.; Blackburn, K.; Bork, R.; Brown, D.A.; Busby, D.; Cardenas, L.; Chandler, A.
2006-01-01
We report on a search for gravitational waves from binary black hole inspirals in the data from the second science run of the LIGO interferometers. The search focused on binary systems with component masses between 3 and 20M · . Optimally oriented binaries with distances up to 1 Mpc could be detected with efficiency of at least 90%. We found no events that could be identified as gravitational waves in the 385.6 hours of data that we searched
Event horizon and scalar potential
International Nuclear Information System (INIS)
Duruisseau, J.P.; Tonnelat, M.A.
1977-01-01
The introduction of a scalar potential with a more general scheme than General Relativity eliminates the event horizon. Among possible solutions, the Schwarzschild one represents a singular case. A study of the geodesic properties of the matching with an approximated interior solution are given. A new definition of the gravitational mass and chi function is deduced. (author)
Gravitational wave signals and cosmological consequences of gravitational reheating
Artymowski, Michał; Czerwińska, Olga; Lalak, Zygmunt; Lewicki, Marek
2018-04-01
Reheating after inflation can proceed even if the inflaton couples to Standard Model (SM) particles only gravitationally. However, particle production during the transition between de-Sitter expansion and a decelerating Universe is rather inefficient and the necessity to recover the visible Universe leads to a non-standard cosmological evolution initially dominated by remnants of the inflaton field. We remain agnostic to the specific dynamics of the inflaton field and discuss a generic scenario in which its remnants behave as a perfect fluid with a general barotropic parameter w. Using CMB and BBN constraints we derive the allowed range of inflationary scales. We also show that this scenario results in a characteristic primordial Gravitational Wave (GW) spectrum which gives hope for observation in upcoming runs of LIGO as well as in other planned experiments.
Measurement of gravitational acceleration of antimatter
International Nuclear Information System (INIS)
Rouhani, S.
1989-12-01
The minute yet effective impact of gravitational potential in the central region of a long tube magnetic container of non-neutral plasmas can be utilized for the measurement of the gravitational acceleration of antimatter particles. The slight change in distribution of plasma particles along the gravitational field affects the internal electric field of the plasma, which in turn affects the frequency of the magnetron motion of its particles. Thus, a rather straightforward relation is established between the gravitational acceleration of the particles and their magnetron frequencies, which is measurable directly, determining the value of the gravitational acceleration. (author). 7 refs, 3 figs
The Japanese space gravitational wave antenna - DECIGO
International Nuclear Information System (INIS)
Kawamura, S; Seto, N; Sato, S; Arai, K; Ando, M; Tsubono, K; Agatsuma, K; Akutsu, T; Akutsu, T; Arase, Y; Nakamura, T; Tanaka, T; Funaki, I; Takashima, T; Numata, K; Ioka, K; Kanda, N; Aoyanagi, Koh-Suke; Araya, A; Asada, H
2008-01-01
DECi-hertz Interferometer Gravitational wave Observatory (DECIGO) is the future Japanese space gravitational wave antenna. The goal of DECIGO is to detect gravitational waves from various kinds of sources mainly between 0.1 Hz and 10 Hz and thus to open a new window of observation for gravitational wave astronomy. DECIGO will consist of three drag-free spacecraft, 1000 km apart from each other, whose relative displacements are measured by a Fabry-Perot Michelson interferometer. We plan to launch DECIGO pathfinder first to demonstrate the technologies required to realize DECIGO and, if possible, to detect gravitational waves from our galaxy or nearby galaxies
Denoising of gravitational wave signals via dictionary learning algorithms
Torres-Forné, Alejandro; Marquina, Antonio; Font, José A.; Ibáñez, José M.
2016-12-01
Gravitational wave astronomy has become a reality after the historical detections accomplished during the first observing run of the two advanced LIGO detectors. In the following years, the number of detections is expected to increase significantly with the full commissioning of the advanced LIGO, advanced Virgo and KAGRA detectors. The development of sophisticated data analysis techniques to improve the opportunities of detection for low signal-to-noise-ratio events is, hence, a most crucial effort. In this paper, we present one such technique, dictionary-learning algorithms, which have been extensively developed in the last few years and successfully applied mostly in the context of image processing. However, to the best of our knowledge, such algorithms have not yet been employed to denoise gravitational wave signals. By building dictionaries from numerical relativity templates of both binary black holes mergers and bursts of rotational core collapse, we show how machine-learning algorithms based on dictionaries can also be successfully applied for gravitational wave denoising. We use a subset of signals from both catalogs, embedded in nonwhite Gaussian noise, to assess our techniques with a large sample of tests and to find the best model parameters. The application of our method to the actual signal GW150914 shows promising results. Dictionary-learning algorithms could be a complementary addition to the gravitational wave data analysis toolkit. They may be used to extract signals from noise and to infer physical parameters if the data are in good enough agreement with the morphology of the dictionary atoms.
Staging Events of Collaborative Design and Learning
DEFF Research Database (Denmark)
Binder, Thomas; Brandt, Eva; Horgen, Turid
1998-01-01
, and "rules of the game"-offers a promising perspective on concurrent engineering. With this as the starting point we report on the findings from a "walk-through" examination of the use of space in the R&D departments at the Danish company Danfoss. Moving from descriptive exploration to action research, we...
DEFF Research Database (Denmark)
things, de-industrialization processes and post-capitalist forms of production and consumption, postmaterialism, the rise of the third sector and collaborative governance. Addressing that gap, this book explores the character, depth and breadth of these disruptions, the creative opportunities for tourism...... that are emerging from them, and how governments are responding to these new challenges. In doing so, the book provides both theoretical and practical insights into the future of tourism in a world that is, paradoxically, becoming both increasingly collaborative and individualized. Table of Contents Preface 1.The......This book employs an interdisciplinary, cross-sectoral lens to explore the collaborative dynamics that are currently disrupting, re-creating and transforming the production and consumption of tourism. House swapping, ridesharing, voluntourism, couchsurfing, dinner hosting, social enterprise...
DEFF Research Database (Denmark)
Kaltoft, Rasmus
The thesis data have been collected in the EU-sponsored project: Collaborative Improvement Tool for the Extended Manufacturing Enterprise, CO-IMPROVE. In this project four universities (Denmark, Ireland, Italy, and The Netherlands), two software vendors (Greece and Sweden) and three companies...... (Denmark, Italy and The Netherlands) each with three to five suppliers were involved. The CO-IMPROVE project and the thesis is based on “action research” and “action learning”. The main aim of the whole project is through actual involvement and actions make the researchers, companies and selected suppliers...... learn how to improve operations in (hopefully) a win-win like manner through collaboration....
DEFF Research Database (Denmark)
Kaltoft, Rasmus
-organisational continuous improvement of their performance, relative to that of other EMEs. Developing a collaborative improvement relationship between companies is a protracted and complex process and, according to some surveys, the failure rate is as low as one to three. This failure rate is affected by a whole range...... of factors. The research presented in this thesis was aimed at identifying these factors and investigating their interplay and influence on the progress and success of the development of the collaborative improvement. This thesis presents our findings regarding the factors found, their interplay...
Current status of large-scale cryogenic gravitational wave telescope
International Nuclear Information System (INIS)
Kuroda, K; Ohashi, M; Miyoki, S; Uchiyama, T; Ishitsuka, H; Yamamoto, K; Kasahara, K; Fujimoto, M-K; Kawamura, S; Takahashi, R; Yamazaki, T; Arai, K; Tatsumi, D; Ueda, A; Fukushima, M; Sato, S; Nagano, S; Tsunesada, Y; Zhu, Zong-Hong; Shintomi, T; Yamamoto, A; Suzuki, T; Saito, Y; Haruyama, T; Sato, N; Higashi, Y; Tomaru, T; Tsubono, K; Ando, M; Takamori, A; Numata, K; Aso, Y; Ueda, K-I; Yoneda, H; Nakagawa, K; Musha, M; Mio, N; Moriwaki, S; Somiya, K; Araya, A; Kanda, N; Telada, S; Tagoshi, H; Nakamura, T; Sasaki, M; Tanaka, T; Oohara, K; Takahashi, H; Miyakawa, O; Tobar, M E
2003-01-01
The large-scale cryogenic gravitational wave telescope (LCGT) project is the proposed advancement of TAMA, which will be able to detect the coalescences of binary neutron stars occurring in our galaxy. LCGT intends to detect the coalescence events within about 240 Mpc, the rate of which is expected to be from 0.1 to several events in a year. LCGT has Fabry-Perot cavities of 3 km baseline and the mirrors are cooled down to a cryogenic temperature of 20 K. It is planned to be built in the underground of Kamioka mine. This paper overviews the revision of the design and the current status of the R and D
Generalized equations of gravitational field
International Nuclear Information System (INIS)
Stanyukovich, K.P.; Borisova, L.B.
1985-01-01
Equations for gravitational fields are obtained on the basis of a generalized Lagrangian Z=f(R) (R is the scalar curvature). Such an approach permits to take into account the evolution of a gravitation ''constant''. An expression for the force Fsub(i) versus the field variability is obtained. Conservation laws are formulated differing from the standard ones by the fact that in the right part of new equations the value Fsub(i) is present that goes to zero at an ultimate passage to the standard Einstein theory. An equation of state is derived for cosmological metrics for a particular case, f=bRsup(1+α) (b=const, α=const)
Gravitational lensing and extra dimensions
International Nuclear Information System (INIS)
He, X-G.; University of Melbourne, Parkville, VIC; Joshi, G.C.; McKellar, B.H.J.
1999-08-01
We study gravitational tensing and the bending of light in low energy scale (M s ) gravity theories with extra space-time dimensions 'n'. We find that due to the presence of spin-2 Kaluza-Klein states from compactification, a correction to the deflection angle with a strong quadratic dependence on the photon energy is introduced. No deviation from the Einstein General Relativity prediction for the deflection angle for photons grazing the Sun in the visible band with 15% accuracy (90% c.l.) implies that the scale M s has to be larger than 1.4(2/(n-2)) 1/4 TeV and approximately 4 TeV for n=2. This lower bound is comparable with that from collider physics constraints. Gravitational tensing experiments with higher energy photons can provide stronger constraints. (authors)
New case of gravitational lensing
Energy Technology Data Exchange (ETDEWEB)
Surdej, J.; Swings, J.-P.; Magain, P.; Borgeest, U.; Kayser, R.; Refsdal, S.; Courvoisier, T.J.-L.; Kellermann, K.I.; Kuehr, H.
1987-10-22
The authors report a brief description of a gravitational lens system UM673 = Q0142 - 100 = PHL3703. It consists of two images, A and B, separated by 2.2 arc s at a redshift zsub(q) = 2.719. The lensing galaxy has also been found. It lies very near the line connecting the two QSO (quasi-stellar objects) images, approx. 0.8 arc s from the fainter one. Application of gravitational optometry to this system leads to a value Msub(o) or approx. = 2.4 x 10/sup 11/ M solar masses for the mass of the lensing galaxy and to ..delta..t approx. 7 weeks for the most likely travel-time difference between the two light paths to the QSO.
Gravitating multidefects from higher dimensions
Giovannini, Massimo
2007-01-01
Warped configurations admitting pairs of gravitating defects are analyzed. After devising a general method for the construction of multidefects, specific examples are presented in the case of higher-dimensional Einstein-Hilbert gravity. The obtained profiles describe diverse physical situations such as (topological) kink-antikink systems, pairs of non-topological solitons and bound configurations of a kink and of a non-topological soliton. In all the mentioned cases the geometry is always well behaved (all relevant curvature invariants are regular) and tends to five-dimensional anti-de Sitter space-time for large asymptotic values of the bulk coordinate. Particular classes of solutions can be generalized to the framework where the gravity part of the action includes, as a correction, the Euler-Gauss-Bonnet combination. After scrutinizing the structure of the zero modes, the obtained results are compared with conventional gravitating configurations containing a single topological defect.
Magnetic tension and gravitational collapse
International Nuclear Information System (INIS)
Tsagas, Christos G
2006-01-01
The gravitational collapse of a magnetized medium is investigated by studying qualitatively the convergence of a timelike family of non-geodesic worldlines in the presence of a magnetic field. Focusing on the field's tension, we illustrate how the winding of the magnetic forcelines due to the fluid's rotation assists the collapse, while shear-like distortions in the distribution of the field's gradients resist contraction. We also show that the relativistic coupling between magnetism and geometry, together with the tension properties of the field, lead to a magneto-curvature stress that opposes the collapse. This tension stress grows stronger with increasing curvature distortion, which means that it could potentially dominate over the gravitational pull of the matter. If this happens, a converging family of non-geodesic worldlines can be prevented from focusing without violating the standard energy conditions
Bayesian Inference on Gravitational Waves
Directory of Open Access Journals (Sweden)
Asad Ali
2015-12-01
Full Text Available The Bayesian approach is increasingly becoming popular among the astrophysics data analysis communities. However, the Pakistan statistics communities are unaware of this fertile interaction between the two disciplines. Bayesian methods have been in use to address astronomical problems since the very birth of the Bayes probability in eighteenth century. Today the Bayesian methods for the detection and parameter estimation of gravitational waves have solid theoretical grounds with a strong promise for the realistic applications. This article aims to introduce the Pakistan statistics communities to the applications of Bayesian Monte Carlo methods in the analysis of gravitational wave data with an overview of the Bayesian signal detection and estimation methods and demonstration by a couple of simplified examples.
Topological quantization of gravitational fields
International Nuclear Information System (INIS)
Patino, Leonardo; Quevedo, Hernando
2005-01-01
We introduce the method of topological quantization for gravitational fields in a systematic manner. First we show that any vacuum solution of Einstein's equations can be represented in a principal fiber bundle with a connection that takes values in the Lie algebra of the Lorentz group. This result is generalized to include the case of gauge matter fields in multiple principal fiber bundles. We present several examples of gravitational configurations that include a gravitomagnetic monopole in linearized gravity, the C-energy of cylindrically symmetric fields, the Reissner-Nordstroem and the Kerr-Newman black holes. As a result of the application of the topological quantization procedure, in all the analyzed examples we obtain conditions implying that the parameters entering the metric in each case satisfy certain discretization relationships
Post-Newtonian gravitational bremsstrahlung
International Nuclear Information System (INIS)
Turner, M.; Will, C.M.
1977-07-01
Formulae and numerical results are presented for the gravitational radiation emitted during a low-deflection encounter between two massive bodies. Results are valid through post-Newtonian order within general relativity. The gravitational waveform, the total luminosity and total emitted energy, the angular distribution of emitted energy, and the frequency spectrum are discussed in detail. A method boosting the accuracy of these quantities to post Newtonian order is also presented. A numerical comparison of results with those of Peters, and of Kovacs and Thorne shows that the post Newtonian method is reliable to better than 0.1 percent at v = 0.1 c, to a few percent at v = 0.35 c, and to 10 to 20 percent at v = 0.5 c
Gravitational waves and dragging effects
Bičák, Jiří; Katz, Joseph; Lynden-Bell, Donald
2008-08-01
Linear and rotational dragging effects of gravitational waves on local inertial frames are studied in purely vacuum spacetimes. First, the linear dragging caused by a simple cylindrical pulse is investigated. Surprisingly strong transverse effects of the pulse are exhibited. The angular momentum in cylindrically symmetric spacetimes is then defined and confronted with some results in the literature. In the main part, a general procedure is developed for studying weak gravitational waves with translational but not axial symmetry which can carry angular momentum. After a suitable averaging the rotation of local inertial frames due to such rotating waves can be calculated explicitly and illustrated graphically. This is done in detail in the accompanying paper. Finally, the rotational dragging is given for strong cylindrical waves interacting with a rotating cosmic string with a small angular momentum.
On the gravitational constant change
International Nuclear Information System (INIS)
Milyukov, V.K.
1986-01-01
The nowadays viewpoint on the problem of G gravitational constant invariability is presented in brief. The methods and results of checking of the G dependence on the nature of substance (checking of the equivalence principle), G dependepce on distance (checking of Newton gravity law) and time (cosmological experiments) are presented. It is pointed out that all performed experiments don't give any reasons to have doubts in G constancy in space and time and G independence on the nature of the substance
Galactic Structures from Gravitational Radii
Directory of Open Access Journals (Sweden)
Salvatore Capozziello
2018-02-01
Full Text Available We demonstrate that the existence of a Noether symmetry in f ( R theories of gravity gives rise to an additional gravitational radius, besides the standard Schwarzschild one, determining the dynamics at galactic scales. By this feature, it is possible to explain the baryonic Tully-Fisher relation and the rotation curve of gas-rich galaxies without the dark matter hypothesis. Furthermore, under the same standard, the Fundamental Plane of elliptical galaxies can be addressed.
On neutron stars and gravitation
International Nuclear Information System (INIS)
Castagnino, M.A.
1987-01-01
From the variational principle for the total internal energy of a neutron star and some restrictions of the form of the metric coefficients, equations of structure which are valid for every metric theory of gravitation have been found. Some simple solutions of the structure equations to find the maximum mass of a neutron star are also presented. Finally it is studied this problem using a post post-Newtonian parametrization
Cylindrical collapse and gravitational waves
Energy Technology Data Exchange (ETDEWEB)
Herrera, L [Escuela de FIsica, Faculdad de Ciencias, Universidad Central de Venezuela, Caracas, Venezuela (Venezuela); Santos, N O [Universite Pierre et Marie Curie, CNRS/FRE 2460 LERMA/ERGA, Tour 22-12, 4eme etage, BoIte 142, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratorio Nacional de Computacao Cientifica, 25651-070 Petropolis RJ (Brazil); Centro Brasileiro de Pesquisas Fisicas, 22290-180 Rio de Janeiro RJ (Brazil)
2005-06-21
We study the matching conditions for a collapsing anisotropic cylindrical perfect fluid, and we show that its radial pressure is non-zero on the surface of the cylinder and proportional to the time-dependent part of the field produced by the collapsing fluid. This result resembles the one that arises for the radiation-though non-gravitational-in the spherically symmetric collapsing dissipative fluid, in the diffusion approximation.
Field theory approach to gravitation
International Nuclear Information System (INIS)
Yilmaz, H.
1978-01-01
A number of authors considered the possibility of formulating a field-theory approach to gravitation with the claim that such an approach would uniquely lead to Einstein's theory of general relativity. In this article it is shown that the field theory approach is more generally applicable and uniqueness cannot be claimed. Theoretical and experimental reasons are given showing that the Einsteinian limit appears to be unviable
Generalized field theory of gravitation
International Nuclear Information System (INIS)
Yilmaz, H.
1976-01-01
It is shown that if, on empirical grounds, one rules out the existence of cosmic fields of Dicke-Brans (scalar) and Will Nordvedt (vector, tensor) type, then the most general experimentally viable and theoretically reasonable theory of gravitation seems to be a LAMBDA-dependent generalization of Einstein and Yilmez theories, which reduces to the former for LAMBDA=0 and to the latter for LAMBDA=1
Gravitational Instabilities in Circumstellar Disks
Kratter, Kaitlin; Lodato, Giuseppe
2016-09-01
Star and planet formation are the complex outcomes of gravitational collapse and angular momentum transport mediated by protostellar and protoplanetary disks. In this review, we focus on the role of gravitational instability in this process. We begin with a brief overview of the observational evidence for massive disks that might be subject to gravitational instability and then highlight the diverse ways in which the instability manifests itself in protostellar and protoplanetary disks: the generation of spiral arms, small-scale turbulence-like density fluctuations, and fragmentation of the disk itself. We present the analytic theory that describes the linear growth phase of the instability supplemented with a survey of numerical simulations that aim to capture the nonlinear evolution. We emphasize the role of thermodynamics and large-scale infall in controlling the outcome of the instability. Despite apparent controversies in the literature, we show a remarkable level of agreement between analytic predictions and numerical results. In the next part of our review, we focus on the astrophysical consequences of the instability. We show that the disks most likely to be gravitationally unstable are young and relatively massive compared with their host star, Md/M*≥0.1. They will develop quasi-stable spiral arms that process infall from the background cloud. Although instability is less likely at later times, once infall becomes less important, the manifestations of the instability are more varied. In this regime, the disk thermodynamics, often regulated by stellar irradiation, dictates the development and evolution of the instability. In some cases the instability may lead to fragmentation into bound companions. These companions are more likely to be brown dwarfs or stars than planetary mass objects. Finally, we highlight open questions related to the development of a turbulent cascade in thin disks and the role of mode-mode coupling in setting the maximum angular
On the linear conformal gravitation
International Nuclear Information System (INIS)
Pal'chik, M.Ya.; Fradkin, E.S.
1984-01-01
Conformal gravitation is analyzed under the assumption that its solution possesses the property of conformal symmetry. This assumption has sense in the case of small distances and only for definite types of matter fields, namely: at special choice of matter fields and their interactions, providing a lack of conformal anomalies; or at definite magnitudes of binding constants, coinciding with the zeroes of the Gell-Mann-Low function. The field equations, of the group-theoretical natura are obtained
Gravitation, Thermodynamics, and Quantum Theory
Wald, Robert M.
1999-01-01
During the past 30 years, research in general relativity has brought to light strong hints of a very deep and fundamental relationship between gravitation, thermodynamics, and quantum theory. The most striking indication of such a relationship comes from black hole thermodynamics, where it appears that certain laws of black hole mechanics are, in fact, simply the ordinary laws of thermodynamics applied to a system containing a black hole. This article will review the present status of black h...
Accelerating Photons with Gravitational Radiation
Shore, Graham M
2001-01-01
The nature of superluminal photon propagation in the gravitational field describing radiation from a time-dependent, isolated source (the Bondi-Sachs metric) is considered in an effective theory which includes interactions which violate the strong equivalence principle. Such interactions are, for example, generated by vacuum polarisation in conventional QED in curved spacetime. The relation of the resulting light-cone modifications to the Peeling Theorem for the Bondi-Sachs spacetime is explained.
Radiatively-induced gravitational leptogenesis
Energy Technology Data Exchange (ETDEWEB)
McDonald, J.I., E-mail: pymcdonald@swansea.ac.uk; Shore, G.M., E-mail: g.m.shore@swansea.ac.uk
2015-12-17
We demonstrate how loop effects in gravitational backgrounds lead to a difference in the propagation of matter and antimatter, and show this is forbidden in flat space due to CPT and translation invariance. This mechanism, which is naturally present in beyond the standard model (BSM) theories exhibiting C and CP violation, generates a curvature-dependent chemical potential for leptons in the low-energy effective Lagrangian, allowing a matter–antimatter asymmetry to be generated in thermodynamic equilibrium, below the BSM scale.
Marka, Zsuzsa; Marka, Szabolcs
2010-04-01
At Amaldi7,which was held 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 USA 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 had started construction. The European-American space mission, LISA Pathfinder, is progressing towards deployment in the foreseeable future and it is expected to pave the way 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 multimessenger approaches to gravitational-wave detection also
Thermal duality and gravitational collapse
International Nuclear Information System (INIS)
Hewitt, Michael
2015-01-01
Thermal duality is a relationship between the behaviour of heterotic string models of the E(8)×E(8) or SO(32) types at inversely related temperatures, a variant of T duality in the Euclidean regime. This duality would have consequences for the nature of the Hagedorn transition in these string models. We propose that the vacuum admits a family of deformations in situations where there are closed surfaces of constant area but high radial acceleration (a string regularized version of a Penrose trapped surface), such as would be formed in situations of extreme gravitational collapse. This would allow a radical resolution of the firewall paradox by allowing quantum effects to significantly modify the spacetime geometry around a collapsed object. A string bremsstrahlung process would convert the kinetic energy of infalling matter in extreme gravitational collapse to form a region of the deformed vacuum, which would be equivalent to forming a high temperature string phase. A heuristic criterion for the conversion process is presented, relating Newtonian gravity to the string tension, suggesting an upper limit to the strength of the gravitational interaction. This conversion process might have observable consequences for charged particles falling into a rotating collapsed object by producing high energy particles via a variant of the Penrose process. (paper)
Probing a gravitational cat state
International Nuclear Information System (INIS)
Anastopoulos, C; Hu, B L
2015-01-01
We investigate the nature of a gravitational two-state system (G2S) in the simplest setup in Newtonian gravity. In a quantum description of matter a single motionless massive particle can in principle be in a superposition state of two spatially separated locations. This superposition state in gravity, or gravitational cat state, would lead to fluctuations in the Newtonian force exerted on a nearby test particle. The central quantity of importance for this inquiry is the energy density correlation. This corresponds to the noise kernel in stochastic gravity theory, evaluated in the weak field nonrelativistic limit. In this limit quantum fluctuations of the stress–energy tensor manifest as the fluctuations of the Newtonian force. We describe the properties of such a G2S system and present two ways of measuring the cat state for the Newtonian force, one by way of a classical probe, the other a quantum harmonic oscillator. Our findings include: (i) mass density fluctuations persist even in single particle systems, and they are of the same order of magnitude as the mean; (ii) a classical probe generically records a non-Markovian fluctuating force; (iii) a quantum probe interacting with the G2S system may undergo Rabi oscillations in a strong coupling regime. This simple prototypical gravitational quantum system could provide a robust testing ground to compare predictions from alternative quantum theories, since the results reported here are based on standard quantum mechanics and classical gravity. (paper)
Gravitational radiation from electromagnetic systems
International Nuclear Information System (INIS)
Nikishov, A.I.; Ritus, V.I.
1989-01-01
It is shown that the spectrum of gravitational radiation of a charge e with mass m, undergoing finite motion in an electromagnetic field, smoothly varying in the neighborhood of the orbit over a region of the order of the radius of curvature, differs in the ultrarelativistic limit from the spectrum of the charge's electromagnetic radiation. The difference consists of the frequency-independent coefficient 4πGm 2 Λ 2 /e 2 , where Λ is of the order of the Lorentz factor of the charge and depends on the direction of the wave vector and on the behavior of the field in the above-indicated region. For a plane-wave external field the gravitational and electromagnetic spectra are strictly proportional to each other for arbitrary velocities of the charge. Localization of the external forces near the orbit violates this proportionality of the spectra and weakens the gravitational radiation by an amount of the order of the square of the Lorentz factor
Coincident Down-chirps in GW150914 Betray the Absence of Event Horizons
Directory of Open Access Journals (Sweden)
Spivey R. J.
2016-07-01
Full Text Available A century has elapsed since gravitational waves were predicted. Their recent detection by the LIGO-Virgo collaboration represents another feather in Einstein’s cap and at- tests to the technological ingenuity of experimentalists. However, the news has been portrayed as affirmation of the existence of black holes, objects whose defining charac- teristics are event horizons. Whilst a gravitational wave chirp is indicative of coalescing bodies and the inferred masses, 29 ± 4 M ⊙ and 36 ± 5 M ⊙ , rule out neutron stars, a promi- nent yet overlooked feature in the Hanford and Livingston spectrograms points to a curious mass ejection during the merger process. The spectral bifurcations, beyond which down-chirps are clearly discernible, suggest that a considerable quantity of mat- ter spiralled away from the binary system at the height of the merger. Since accretion disks cannot survive until the latter stages of coalescence , a black hole model seems un- tenable, and Einstein’s expectation that black holes can neither form nor ingest matter in a universe of finite age would appear to be upheld. By virtue of general relativity’s logi- cal consistency and the fact that gravity propagates at light speed, gravitational collapse must terminate with the formation of pathology-free temporally suspended objects.
Event horizon image within black hole shadow
Dokuchaev, V. I.; Nazarova, N. O.
2018-01-01
The external border of the black hole shadow is washed out by radiation from matter plunging into black hole and approaching the event horizon. This effect will crucially influence the results of future observations by the Event Horizon Telescope. We show that gravitational lensing of the luminous matter plunging into black hole provides the event horizon visualization within black hole shadow. The lensed image of the event horizon is formed by the last highly red-shifted photons emitted by t...
DEFF Research Database (Denmark)
Sonnenwald, Diane H.
1995-01-01
. The model describes design phases, roles, themes, and intergroup communication networks as they evolve throughout the design process and characterizes design as a process of "contested collaboration". It is a first step towards a predictive design model that suggests strategies which may help participants...
DEFF Research Database (Denmark)
Bohøj, Morten; Borchorst, Nikolaj Gandrup; Bouvin, Niels Olof
2010-01-01
This paper explores timelines as a web-based tool for collaboration between citizens and municipal caseworkers. The paper takes its outset in a case study of planning and control of parental leave; a process that may involve surprisingly many actors. As part of the case study, a web-based timeline...
DEFF Research Database (Denmark)
Muller, Michael; Neureiter, Katja; Verdezoto, Nervo
2016-01-01
Previous workshops and papers have examined how individual users adopt and adapt technologies to meet their own local needs, by “completing design through use.” However, there has been little systematic study of how groups of people engage collaboratively in these activities. This workshop opens ...
Broderick, Debora
2014-01-01
This practitioner research study investigates the power of multimodal texts within a real-world context and argues that a participatory culture focused on literary arts offers marginalized high school students opportunities for collaborative design and authoring. Additionally, this article invites educators to rethink the at-risk label. This…
Signs of cosmic rays in gravitational wave detectors
International Nuclear Information System (INIS)
Tavares, Denis Borgarelli
2010-01-01
One of the phenomena predicted by Einstein in the derivation of general relativity is the existence of small perturbations of the metric that he named gravitational waves. As they travel through space oscillates the space-time according to its polarization. This is the only major prediction of general relativity not yet proven completely. The small signal generated by the passage of a gravitational wave compared to the noise in the system of detection makes their direct detection one challenge of modern science. In this paper we study the noise generated by cosmic rays in the gravitational antenna Mario Schenberg, located in the city of Sao Paulo. Single muons and hadrons flux measurements held in the northern hemisphere were used to calculate the expected flux of these particles in the city of Sao Paulo. The calculation of the energy deposited in the detector of gravitational waves from cosmic rays was performed by Monte Carlo simulations using Geant4. The transport of muons and protons, with several energy and some different angles of incidence, across the building and the resonant sphere was simulated. We developed a thermo-acoustic model, called multi-point, suitable for calculating the energy deposited in the normal modes from the energy deposited on the sphere by elementary particles. With these results we calculate the expected rate of cosmic ray signals in the main detection mode of gravitational waves, nl = 12, of the Mario Schenberg detector, for temperatures T noise between 10 -5 and 10 -7 K. The results showed for the designed for 4.2 K sensitivity of the Mario Schenberg detector that the rate of signals due to cosmic rays is very small, being around 5 events per day. However, when it will reach the quantum limit will be needed a more detailed analysis of the antenna signal output, since the expected number of cosmic ray noise increases considerably, reaching about 250 signals per day. (author)
Gravitational-Wave Luminosity of Binary Neutron Stars Mergers
Zappa, Francesco; Bernuzzi, Sebastiano; Radice, David; Perego, Albino; Dietrich, Tim
2018-03-01
We study the gravitational-wave peak luminosity and radiated energy of quasicircular neutron star mergers using a large sample of numerical relativity simulations with different binary parameters and input physics. The peak luminosity for all the binaries can be described in terms of the mass ratio and of the leading-order post-Newtonian tidal parameter solely. The mergers resulting in a prompt collapse to black hole have the largest peak luminosities. However, the largest amount of energy per unit mass is radiated by mergers that produce a hypermassive neutron star or a massive neutron star remnant. We quantify the gravitational-wave luminosity of binary neutron star merger events, and set upper limits on the radiated energy and the remnant angular momentum from these events. We find that there is an empirical universal relation connecting the total gravitational radiation and the angular momentum of the remnant. Our results constrain the final spin of the remnant black hole and also indicate that stable neutron star remnant forms with super-Keplerian angular momentum.
Gravitational-Wave Luminosity of Binary Neutron Stars Mergers.
Zappa, Francesco; Bernuzzi, Sebastiano; Radice, David; Perego, Albino; Dietrich, Tim
2018-03-16
We study the gravitational-wave peak luminosity and radiated energy of quasicircular neutron star mergers using a large sample of numerical relativity simulations with different binary parameters and input physics. The peak luminosity for all the binaries can be described in terms of the mass ratio and of the leading-order post-Newtonian tidal parameter solely. The mergers resulting in a prompt collapse to black hole have the largest peak luminosities. However, the largest amount of energy per unit mass is radiated by mergers that produce a hypermassive neutron star or a massive neutron star remnant. We quantify the gravitational-wave luminosity of binary neutron star merger events, and set upper limits on the radiated energy and the remnant angular momentum from these events. We find that there is an empirical universal relation connecting the total gravitational radiation and the angular momentum of the remnant. Our results constrain the final spin of the remnant black hole and also indicate that stable neutron star remnant forms with super-Keplerian angular momentum.
Localizing gravitational wave sources with single-baseline atom interferometers
Graham, Peter W.; Jung, Sunghoon
2018-02-01
Localizing sources on the sky is crucial for realizing the full potential of gravitational waves for astronomy, astrophysics, and cosmology. We show that the midfrequency band, roughly 0.03 to 10 Hz, has significant potential for angular localization. The angular location is measured through the changing Doppler shift as the detector orbits the Sun. This band maximizes the effect since these are the highest frequencies in which sources live for several months. Atom interferometer detectors can observe in the midfrequency band, and even with just a single baseline they can exploit this effect for sensitive angular localization. The single-baseline orbits around the Earth and the Sun, causing it to reorient and change position significantly during the lifetime of the source, and making it similar to having multiple baselines/detectors. For example, atomic detectors could predict the location of upcoming black hole or neutron star merger events with sufficient accuracy to allow optical and other electromagnetic telescopes to observe these events simultaneously. Thus, midband atomic detectors are complementary to other gravitational wave detectors and will help complete the observation of a broad range of the gravitational spectrum.
Performative Tools and Collaborative Learning
DEFF Research Database (Denmark)
Minder, Bettina; Lassen, Astrid Heidemann
of performative tools used in transdisciplinary events for collaborative learning. The results of this single case study add to extant knowledge- and learning literature by providing the reader with a rich description of characteristics and learning functions of performative tools in transdisciplinary events......The use of performative tools can support collaborative learning across knowledge domains (i.e. science and practice), because they create new spaces for dialog. However, so far innovation literature provides little answers to the important discussion of how to describe the effects and requirements...... and a description of how they interrelate with the specific setting of such an event. Furthermore, they complement previous findings by relating performative tools to collaborative learning for knowledge intensive ideas....
Hydrodynamics, fields and constants in gravitational theory
International Nuclear Information System (INIS)
Stanyukovich, K.P.; Mel'nikov, V.N.
1983-01-01
Results of original inveatigations into problems of standard gravitation theory and its generalizations are presented. The main attention is paid to the application of methods of continuous media techniques in the gravitation theory; to the specification of the gravitation role in phenomena of macro- and microworld, accurate solutions in the case, when the medium is the matter, assigned by hydrodynamic energy-momentum tensor; and to accurate solutions for the case when the medium is the field. GRT generalizations are analyzed, such as the new cosmologic hypothesis which is based on the gravitation vacuum theory. Investigations are performed into the quantization of cosmological models, effects of spontaneous symmetry violation and particle production in cosmology. Graeity theory with fundamental Higgs field is suggested in the framework of which in the atomic unit number one can explain possible variations of the effective gravitational bonds, and in the gravitation bond, variations of masses of all particles
Gravitational waves from instabilities in relativistic stars
International Nuclear Information System (INIS)
Andersson, Nils
2003-01-01
This paper provides an overview of stellar instabilities as sources of gravitational waves. The aim is to put recent work on secular and dynamical instabilities in compact stars in context, and to summarize the current thinking about the detectability of gravitational waves from various scenarios. As a new generation of kilometre length interferometric detectors is now coming online this is a highly topical theme. The review is motivated by two key questions for future gravitational-wave astronomy: are the gravitational waves from various instabilities detectable? If so, what can these gravitational-wave signals teach us about neutron star physics? Even though we may not have clear answers to these questions, recent studies of the dynamical bar-mode instability and the secular r-mode instability have provided new insights into many of the difficult issues involved in modelling unstable stars as gravitational-wave sources. (topical review)
Production of Purely Gravitational Dark Matter
Ema, Yohei; Nakayama, Kazunori; Tang, Yong
2018-01-01
In the purely gravitational dark matter scenario, the dark matter particle does not have any interaction except for gravitational one. We study the gravitational particle production of dark matter particle in such a minimal setup and show that correct amount of dark matter can be produced depending on the inflation model and the dark matter mass. In particular, we carefully evaluate the particle production rate from the transition epoch to the inflaton oscillation epoch in a realistic inflati...
Compensation for gravitational sag of bent mirror
Energy Technology Data Exchange (ETDEWEB)
Mao, Chengwen; Jiang, Hui; He, Yan; Liang, Dongxu; Lan, Xuying; Yan, Shuai [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, CAS, Shanghai 201800 (China); Shu, De-ming [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Li, Aiguo, E-mail: aiguo.li@sinap.ac.cn [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, CAS, Shanghai 201800 (China)
2017-05-01
The gravitational sag of aspheric bent mirrors with face-up or face-down geometry produces a nonnegligible optical error. As an effective compensation, width optimization is used to match the combined effects of the gravitational and bending moments. This method is described by analytical expressions and two calculation algorithms. The results of theoretical simulations and finite element analysis have proved that this method can reduce the slope error resulting from gravitational sag to the level of nano radians.
Compensation for gravitational sag of bent mirror
International Nuclear Information System (INIS)
Mao, Chengwen; Jiang, Hui; He, Yan; Liang, Dongxu; Lan, Xuying; Yan, Shuai; Shu, De-ming; Li, Aiguo
2017-01-01
The gravitational sag of aspheric bent mirrors with face-up or face-down geometry produces a nonnegligible optical error. As an effective compensation, width optimization is used to match the combined effects of the gravitational and bending moments. This method is described by analytical expressions and two calculation algorithms. The results of theoretical simulations and finite element analysis have proved that this method can reduce the slope error resulting from gravitational sag to the level of nano radians.
Progress in gravitational wave detection: Interferometers
International Nuclear Information System (INIS)
Kuroda, Kazuaki
2002-01-01
A gravitational wave (GW) is a physical entity of space-time derived from Einstein's theory of general relativity. Challenging projects to observe gravitational waves are being conducted throughout the world. A Japanese project involving a 300 m baseline laser interferometer, TAMA, achieved 1000 hr of continuous observation with the best sensitivity in the world during the summer of 2001. After achieving promising results, the realization of LCGT (Large-scale Cryogenic Gravitational wave Telescope) will become possible in the near future
Limiting the effects of earthquakes on gravitational-wave interferometers
Coughlin, Michael; Earle, Paul; Harms, Jan; Biscans, Sebastien; Buchanan, Christopher; Coughlin, Eric; Donovan, Fred; Fee, Jeremy; Gabbard, Hunter; Guy, Michelle; Mukund, Nikhil; Perry, Matthew
2017-01-01
Ground-based gravitational wave interferometers such as the Laser Interferometer Gravitational-wave Observatory (LIGO) are susceptible to ground shaking from high-magnitude teleseismic events, which can interrupt their operation in science mode and significantly reduce their duty cycle. It can take several hours for a detector to stabilize enough to return to its nominal state for scientific observations. The down time can be reduced if advance warning of impending shaking is received and the impact is suppressed in the isolation system with the goal of maintaining stable operation even at the expense of increased instrumental noise. Here, we describe an early warning system for modern gravitational-wave observatories. The system relies on near real-time earthquake alerts provided by the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA). Preliminary low latency hypocenter and magnitude information is generally available in 5 to 20 min of a significant earthquake depending on its magnitude and location. The alerts are used to estimate arrival times and ground velocities at the gravitational-wave detectors. In general, 90% of the predictions for ground-motion amplitude are within a factor of 5 of measured values. The error in both arrival time and ground-motion prediction introduced by using preliminary, rather than final, hypocenter and magnitude information is minimal. By using a machine learning algorithm, we develop a prediction model that calculates the probability that a given earthquake will prevent a detector from taking data. Our initial results indicate that by using detector control configuration changes, we could prevent interruption of operation from 40 to 100 earthquake events in a 6-month time-period.
Limiting the effects of earthquakes on gravitational-wave interferometers
International Nuclear Information System (INIS)
Coughlin, Michael; Earle, Paul; Harms, Jan; Biscans, Sebastien; Donovan, Fred; Buchanan, Christopher; Coughlin, Eric; Fee, Jeremy; Guy, Michelle; Gabbard, Hunter; Mukund, Nikhil; Perry, Matthew
2017-01-01
Ground-based gravitational wave interferometers such as the Laser Interferometer Gravitational-wave Observatory (LIGO) are susceptible to ground shaking from high-magnitude teleseismic events, which can interrupt their operation in science mode and significantly reduce their duty cycle. It can take several hours for a detector to stabilize enough to return to its nominal state for scientific observations. The down time can be reduced if advance warning of impending shaking is received and the impact is suppressed in the isolation system with the goal of maintaining stable operation even at the expense of increased instrumental noise. Here, we describe an early warning system for modern gravitational-wave observatories. The system relies on near real-time earthquake alerts provided by the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA). Preliminary low latency hypocenter and magnitude information is generally available in 5 to 20 min of a significant earthquake depending on its magnitude and location. The alerts are used to estimate arrival times and ground velocities at the gravitational-wave detectors. In general, 90% of the predictions for ground-motion amplitude are within a factor of 5 of measured values. The error in both arrival time and ground-motion prediction introduced by using preliminary, rather than final, hypocenter and magnitude information is minimal. By using a machine learning algorithm, we develop a prediction model that calculates the probability that a given earthquake will prevent a detector from taking data. Our initial results indicate that by using detector control configuration changes, we could prevent interruption of operation from 40 to 100 earthquake events in a 6-month time-period. (paper)
Rahbek Gjerdrum Pedersen, Esben; Netter, Sarah
2013-01-01
Purpose: The purpose of this paper is to explore barriers and opportunities for business models based on the ideas of collaborative consumption within the fashion industry. Design/methodology/approach: The analysis is based on a multiple-‐‑case study of Scandinavian fashion libraries – a new, clothes-‐‑sharing concept that has emerged as a fashion niche within the last decade. Findings: It is concluded that fashion libraries offers interesting perspectives, e.g. by allow...
DEFF Research Database (Denmark)
Johansson, Martin Wetterstrand
2006-01-01
Sketching is a most central activity with in most design projects. But what happens if we adopt the ideas of collaborative design and invite participants that are not trained to sketch in to the design process, how can they participate in this central activity? This paper oﬀers an introduction to...... the design material has been used to co- author possible futures within the scope of design sessions....
Veto analysis for gravitational wave burst signals in TAMA300 data using an ALF filter
International Nuclear Information System (INIS)
Akutsu, T; Ando, M; Kanda, N; Tatsumi, D; Telada, S; Miyoki, S; Ohashi, M
2006-01-01
Data taken by interferometers for gravitational waves include noises caused by instabilities of the interferometers. Veto analyses to remove false events caused by detectors are then necessary to detect real gravitational waves or to obtain a lower upper limit. In this paper, a veto analysis with an environmental monitor channel was implemented. We calculate the trigger rate of TAMA300 data and demonstrate the veto analysis using an alternative linear fit (ALF) filter. A threshold for the environmental monitor channel signals is set to be at 1% of the false dismissal rate. The result shows a 1/10-1/1000 reduction of trigger event rates
Characterization of Transient Noise in Advanced LIGO Relevant to Gravitational Wave Signal GW150914
Abbott, B. P.; Abbott, R.; Abbott, T. D.; Abernathy, M. R.; Acernese, F.; Ackley, K.; Adamo, M.; Adams, C.; Adams, T.; Camp, Jordan B.
2016-01-01
On 14 September 2015, a gravitational wave signal from a coalescing black hole binary system was observed by the Advanced LIGO detectors. This paper describes the transient noise backgrounds used to determine the significance of the event (designated GW150914) and presents the results of investigations into potential correlated or uncorrelated sources of transient noise in the detectors around the time of the event. The detectors were operating nominally at the time of GW150914. We have ruled out environmental influences and non-Gaussian instrument noise at either LIGO detector as the cause of the observed gravitational wave signal.
Effect of undetected gravitational lenses on statistical measures of quasar evolution
International Nuclear Information System (INIS)
Turner, E.L.
1980-01-01
Brightness amplifications by undetected gravitational lenses could be responsible in part for the apparent evolution of quasars, particularly for those which appear to be of high luminosity. It is shown that values of Vover-bar/over-barVover-bar/sub M/> or =0.6 and number-magnitude slopes > or =0.9 need not necessarily imply source density evolution if lensing events are common. Quasar samples which are defined by flux limits and minimum luminosities will preferentially include gravitational lens systems. Even if lensing events are quite rare, a large fraction of the lensed quasars will appear more luminous than the most luminous unlensed quasar
Search for gravitational waves associated with γ-ray bursts detected by the interplanetary network.
Aasi, J; Abbott, B P; Abbott, R; Abbott, T; Abernathy, M R; Acernese, F; Ackley, K; Adams, C; Adams, T; Addesso, P; Adhikari, R X; Affeldt, C; Agathos, M; Aggarwal, N; Aguiar, O D; Ajith, P; Alemic, A; Allen, B; Allocca, A; Amariutei, D; Andersen, M; Anderson, R A; Anderson, S B; Anderson, W G; Arai, K; Araya, M C; Arceneaux, C; Areeda, J S; Ast, S; Aston, S M; Astone, P; Aufmuth, P; Augustus, H; Aulbert, C; Aylott, B E; Babak, S; Baker, P T; Ballardin, G; Ballmer, S W; Barayoga, J C; Barbet, M; Barish, B C; Barker, D; Barone, F; Barr, B; Barsotti, L; Barsuglia, M; Barton, M A; Bartos, I; Bassiri, R; Basti, A; Batch, J C; Bauchrowitz, J; Bauer, Th S; Baune, C; Bavigadda, V; Behnke, B; Bejger, M; Beker, M G; Belczynski, C; Bell, A S; Bell, C; Bergmann, G; Bersanetti, D; Bertolini, A; Betzwieser, J; Bilenko, I A; Billingsley, G; Birch, J; Biscans, S; Bitossi, M; Biwer, C; Bizouard, M A; Black, E; Blackburn, J K; Blackburn, L; Blair, D; Bloemen, S; Bock, O; Bodiya, T P; Boer, M; Bogaert, G; Bogan, C; Bond, C; Bondu, F; Bonelli, L; Bonnand, R; Bork, R; Born, M; Boschi, V; Bose, Sukanta; Bosi, L; Bradaschia, C; Brady, P R; Braginsky, V B; Branchesi, M; Brau, J E; Briant, T; Bridges, D O; Brillet, A; Brinkmann, M; Brisson, V; Brooks, A F; Brown, D A; Brown, D D; Brückner, F; Buchman, S; Buikema, A; Bulik, T; Bulten, H J; Buonanno, A; Burman, R; Buskulic, D; Buy, C; Cadonati, L; Cagnoli, G; Calderón Bustillo, J; Calloni, E; Camp, J B; Campsie, P; Cannon, K C; Canuel, B; Cao, J; Capano, C D; Carbognani, F; Carbone, L; Caride, S; Castaldi, G; Caudill, S; Cavaglià, M; Cavalier, F; Cavalieri, R; Celerier, C; Cella, G; Cepeda, C; Cesarini, E; Chakraborty, R; Chalermsongsak, T; Chamberlin, S J; Chao, S; Charlton, P; Chassande-Mottin, E; Chen, X; Chen, Y; Chincarini, A; Chiummo, A; Cho, H S; Cho, M; Chow, J H; Christensen, N; Chu, Q; Chua, S S Y; Chung, S; Ciani, G; Clara, F; Clark, D E; Clark, J A; Clayton, J H; Cleva, F; Coccia, E; Cohadon, P-F; Colla, A; Collette, C; Colombini, M; Cominsky, L; Constancio, M; Conte, A; Cook, D; Corbitt, T R; Cornish, N; Corsi, A; Costa, C A; Coughlin, M W; Coulon, J-P; Countryman, S; Couvares, P; Coward, D M; Cowart, M J; Coyne, D C; Coyne, R; Craig, K; Creighton, J D E; Croce, R P; Crowder, S G; Cumming, A; Cunningham, L; Cuoco, E; Cutler, C; Dahl, K; Dal Canton, T; Damjanic, M; Danilishin, S L; D'Antonio, S; Danzmann, K; Dattilo, V; Daveloza, H; Davier, M; Davies, G S; Daw, E J; Day, R; Dayanga, T; DeBra, D; Debreczeni, G; Degallaix, J; Deléglise, S; Del Pozzo, W; Denker, T; Dent, T; Dereli, H; Dergachev, V; De Rosa, R; DeRosa, R T; DeSalvo, R; Dhurandhar, S; Díaz, M; Dickson, J; Di Fiore, L; Di Lieto, A; Di Palma, I; Di Virgilio, A; Dolique, V; Dominguez, E; Donovan, F; Dooley, K L; Doravari, S; Douglas, R; Downes, T P; Drago, M; Drever, R W P; Driggers, J C; Du, Z; Ducrot, M; Dwyer, S; Eberle, T; Edo, T; Edwards, M; Effler, A; Eggenstein, H-B; Ehrens, P; Eichholz, J; Eikenberry, S S; Endrőczi, G; Essick, R; Etzel, T; Evans, M; Evans, T; Factourovich, M; Fafone, V; Fairhurst, S; Fan, X; Fang, Q; Farinon, S; Farr, B; Farr, W M; Favata, M; Fazi, D; Fehrmann, H; Fejer, M M; Feldbaum, D; Feroz, F; Ferrante, I; Ferreira, E C; Ferrini, F; Fidecaro, F; Finn, L S; Fiori, I; Fisher, R P; Flaminio, R; Fournier, J-D; Franco, S; Frasca, S; Frasconi, F; Frede, M; Frei, Z; Freise, A; Frey, R; Fricke, T T; Fritschel, P; Frolov, V V; Fulda, P; Fyffe, M; Gair, J R; Gammaitoni, L; Gaonkar, S; Garufi, F; Gehrels, N; Gemme, G; Gendre, B; Genin, E; Gennai, A; Ghosh, S; Giaime, J A; Giardina, K D; Giazotto, A; Gleason, J; Goetz, E; Goetz, R; Gondan, L; González, G; Gordon, N; Gorodetsky, M L; Gossan, S; Goßler, S; Gouaty, R; Gräf, C; Graff, P B; Granata, M; Grant, A; Gras, S; Gray, C; Greenhalgh, R J S; Gretarsson, A M; Groot, P; Grote, H; Grover, K; Grunewald, S; Guidi, G M; Guido, C J; Gushwa, K; Gustafson, E K; Gustafson, R; Ha, J; Hall, E D; Hamilton, W; Hammer, D; Hammond, G; Hanke, M; Hanks, J; Hanna, C; Hannam, M D; Hanson, J; Harms, J; Harry, G M; Harry, I W; Harstad, E D; Hart, M; Hartman, M T; Haster, C-J; Haughian, K; Heidmann, A; Heintze, M; Heitmann, H; Hello, P; Hemming, G; Hendry, M; Heng, I S; Heptonstall, A W; Heurs, M; Hewitson, M; Hild, S; Hoak, D; Hodge, K A; Hofman, D; Holt, K; Hopkins, P; Horrom, T; Hoske, D; Hosken, D J; Hough, J; Howell, E J; Hu, Y; Huerta, E; Hughey, B; Husa, S; Huttner, S H; Huynh, M; Huynh-Dinh, T; Idrisy, A; Ingram, D R; Inta, R; Islas, G; Isogai, T; Ivanov, A; Iyer, B R; Izumi, K; Jacobson, M; Jang, H; Jaranowski, P; Ji, Y; Jiménez-Forteza, F; Johnson, W W; Jones, D I; Jones, R; Jonker, R J G; Ju, L; Haris, K; Kalmus, P; Kalogera, V; Kandhasamy, S; Kang, G; Kanner, J B; Karlen, J; Kasprzack, M; Katsavounidis, E; Katzman, W; Kaufer, H; Kaufer, S; Kaur, T; Kawabe, K; Kawazoe, F; Kéfélian, F; Keiser, G M; Keitel, D; Kelley, D B; Kells, W; Keppel, D G; Khalaidovski, A; Khalili, F Y; Khazanov, E A; Kim, C; Kim, K; Kim, N G; Kim, N; Kim, S; Kim, Y-M; King, E J; King, P J; Kinzel, D L; Kissel, J S; Klimenko, S; Kline, J; Koehlenbeck, S; Kokeyama, K; Kondrashov, V; Koranda, S; Korth, W Z; Kowalska, I; Kozak, D B; Kringel, V; Krishnan, B; Królak, A; Kuehn, G; Kumar, A; Kumar, D Nanda; Kumar, P; Kumar, R; Kuo, L; Kutynia, A; Lam, P K; Landry, M; Lantz, B; Larson, S; Lasky, P D; Lazzarini, A; Lazzaro, C; Leaci, P; Leavey, S; Lebigot, E O; Lee, C H; Lee, H K; Lee, H M; Lee, J; Lee, P J; Leonardi, M; Leong, J R; Leonor, I; Le Roux, A; Leroy, N; Letendre, N; Levin, Y; Levine, B; Lewis, J; Li, T G F; Libbrecht, K; Libson, A; Lin, A C; Littenberg, T B; Lockerbie, N A; Lockett, V; Lodhia, D; Loew, K; Logue, J; Lombardi, A L; Lopez, E; Lorenzini, M; Loriette, V; Lormand, M; Losurdo, G; Lough, J; Lubinski, M J; Lück, H; Lundgren, A P; Ma, Y; Macdonald, E P; MacDonald, T; Machenschalk, B; MacInnis, M; Macleod, D M; Magaña-Sandoval, F; Magee, R; Mageswaran, M; Maglione, C; Mailand, K; Majorana, E; Maksimovic, I; Malvezzi, V; Man, N; Manca, G M; Mandel, I; Mandic, V; Mangano, V; Mangini, N M; Mansell, G; Mantovani, M; Marchesoni, F; Marion, F; Márka, S; Márka, Z; Markosyan, A; Maros, E; Marque, J; Martelli, F; Martin, I W; Martin, R M; Martinelli, L; Martynov, D; Marx, J N; Mason, K; Masserot, A; Massinger, T J; Matichard, F; Matone, L; Mavalvala, N; May, G; Mazumder, N; Mazzolo, G; McCarthy, R; McClelland, D E; McGuire, S C; McIntyre, G; McIver, J; McLin, K; Meacher, D; Meadors, G D; Mehmet, M; Meidam, J; Meinders, M; Melatos, A; Mendell, G; Mercer, R A; Meshkov, S; Messenger, C; Meyer, M S; Meyers, P M; Mezzani, F; Miao, H; Michel, C; Mikhailov, E E; Milano, L; Miller, J; Minenkov, Y; Mingarelli, C M F; Mishra, C; Mitra, S; Mitrofanov, V P; Mitselmakher, G; Mittleman, R; Moe, B; Moggi, A; Mohan, M; Mohapatra, S R P; Moraru, D; Moreno, G; Morgado, N; Morriss, S R; Mossavi, K; Mours, B; Mow-Lowry, C M; Mueller, C L; Mueller, G; Mukherjee, S; Mullavey, A; Munch, J; Murphy, D; Murray, P G; Mytidis, A; Nagy, M F; Nardecchia, I; Naticchioni, L; Nayak, R K; Necula, V; Nelemans, G; Neri, I; Neri, M; Newton, G; Nguyen, T; Nielsen, A B; Nissanke, S; Nitz, A H; Nocera, F; Nolting, D; Normandin, M E N; Nuttall, L K; Ochsner, E; O'Dell, J; Oelker, E; Oh, J J; Oh, S H; Ohme, F; Omar, S; Oppermann, P; Oram, R; O'Reilly, B; Ortega, W; O'Shaughnessy, R; Osthelder, C; Ottaway, D J; Ottens, R S; Overmier, H; Owen, B J; Padilla, C; Pai, A; Palashov, O; Palomba, C; Pan, H; Pan, Y; Pankow, C; Paoletti, F; Papa, M A; Paris, H; Pasqualetti, A; Passaquieti, R; Passuello, D; Pedraza, M; Pele, A; Penn, S; Perreca, A; Phelps, M; Pichot, M; Pickenpack, M; Piergiovanni, F; Pierro, V; Pinard, L; Pinto, I M; Pitkin, M; Poeld, J; Poggiani, R; Poteomkin, A; Powell, J; Prasad, J; Predoi, V; Premachandra, S; Prestegard, T; Price, L R; Prijatelj, M; Privitera, S; Prodi, G A; Prokhorov, L; Puncken, O; Punturo, M; Puppo, P; Pürrer, M; Qin, J; Quetschke, V; Quintero, E; Quitzow-James, R; Raab, F J; Rabeling, D S; Rácz, I; Radkins, H; Raffai, P; Raja, S; Rajalakshmi, G; Rakhmanov, M; Ramet, C; Ramirez, K; Rapagnani, P; Raymond, V; Razzano, M; Re, V; Recchia, S; Reed, C M; Regimbau, T; Reid, S; Reitze, D H; Reula, O; Rhoades, E; Ricci, F; Riesen, R; Riles, K; Robertson, N A; Robinet, F; Rocchi, A; Roddy, S B; Rolland, L; Rollins, J G; Romano, R; Romanov, G; Romie, J H; Rosińska, D; Rowan, S; Rüdiger, A; Ruggi, P; Ryan, K; Salemi, F; Sammut, L; Sandberg, V; Sanders, J R; Sankar, S; Sannibale, V; Santiago-Prieto, I; Saracco, E; Sassolas, B; Sathyaprakash, B S; Saulson, P R; Savage, R; Scheuer, J; Schilling, R; Schilman, M; Schmidt, P; Schnabel, R; Schofield, R M S; Schreiber, E; Schuette, D; Schutz, B F; Scott, J; Scott, S M; Sellers, D; Sengupta, A S; Sentenac, D; Sequino, V; Sergeev, A; Shaddock, D A; Shah, S; Shahriar, M S; Shaltev, M; Shao, Z; Shapiro, B; Shawhan, P; Shoemaker, D H; Sidery, T L; Siellez, K; Siemens, X; Sigg, D; Simakov, D; Singer, A; Singer, L; Singh, R; Sintes, A M; Slagmolen, B J J; Slutsky, J; Smith, J R; Smith, M R; Smith, R J E; Smith-Lefebvre, N D; Son, E J; Sorazu, B; Souradeep, T; Staley, A; Stebbins, J; Steinke, M; Steinlechner, J; Steinlechner, S; Stephens, B C; Steplewski, S; Stevenson, S; Stone, R; Stops, D; Strain, K A; Straniero, N; Strigin, S; Sturani, R; Stuver, A L; Summerscales, T Z; Susmithan, S; Sutton, P J; Swinkels, B; Tacca, M; Talukder, D; Tanner, D B; Tao, J; Tarabrin, S P; Taylor, R; Tellez, G; Thirugnanasambandam, M P; Thomas, M; Thomas, P; Thorne, K A; Thorne, K S; Thrane, E; Tiwari, V; Tokmakov, K V; Tomlinson, C; Tonelli, M; Torres, C V; Torrie, C I; Travasso, F; Traylor, G; Tse, M; Tshilumba, D; Tuennermann, H; Ugolini, D; Unnikrishnan, C S; Urban, A L; Usman, S A; Vahlbruch, H; Vajente, G; Valdes, G; Vallisneri, M; van Beuzekom, M; van den Brand, J F J; Van Den Broeck, C; van der Sluys, M V; van Heijningen, J; van Veggel, A A; Vass, S; Vasúth, M; Vaulin, R; Vecchio, A; Vedovato, G; Veitch, J; Veitch, P J; Venkateswara, K; Verkindt, D; Vetrano, F; Viceré, A; Vincent-Finley, R; Vinet, J-Y; Vitale, S; Vo, T; Vocca, H; Vorvick, C; Vousden, W D; Vyachanin, S P; Wade, A R; Wade, L; Wade, M; Walker, M; Wallace, L; Walsh, S; Wang, M; Wang, X; Ward, R L; Was, M; Weaver, B; Wei, L-W; Weinert, M; Weinstein, A J; Weiss, R; Welborn, T; Wen, L; Wessels, P; West, M; Westphal, T; Wette, K; Whelan, J T; White, D J; Whiting, B F; Wiesner, K; Wilkinson, C; Williams, K; Williams, L; Williams, R; Williams, T D; Williamson, A R; Willis, J L; Willke, B; Wimmer, M; Winkler, W; Wipf, C C; Wiseman, A G; Wittel, H; Woan, G; Wolovick, N; Worden, J; Wu, Y; Yablon, J; Yakushin, I; Yam, W; Yamamoto, H; Yancey, C C; Yang, H; Yoshida, S; Yvert, M; Zadrożny, A; Zanolin, M; Zendri, J-P; Zhang, Fan; Zhang, L; Zhao, C; Zhu, H; Zhu, X J; Zucker, M E; Zuraw, S; Zweizig, J; Aptekar, R L; Atteia, J L; Cline, T; Connaughton, V; Frederiks, D D; Golenetskii, S V; Hurley, K; Krimm, H A; Marisaldi, M; Pal'shin, V D; Palmer, D; Svinkin, D S; Terada, Y; von Kienlin, A
2014-07-04
We present the results of a search for gravitational waves associated with 223 γ-ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(-2)M⊙c(2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.
Aasi, J.; Abbott, B. P.; Abbott, R.; Abbott, T.; Abernathy, M. R.; Acernese, F.; Blackbum, L.; Camp, J. B.; Gehrels, N.; Graff, P. B.;
2014-01-01
We present the results of a search for gravitational waves associated with 223 gamma ray bursts (GRBs) detected by the InterPlanetary Network (IPN) in 2005-2010 during LIGO's fifth and sixth science runs and Virgo's first, second, and third science runs. The IPN satellites provide accurate times of the bursts and sky localizations that vary significantly from degree scale to hundreds of square degrees. We search for both a well-modeled binary coalescence signal, the favored progenitor model for short GRBs, and for generic, unmodeled gravitational wave bursts. Both searches use the event time and sky localization to improve the gravitational wave search sensitivity as compared to corresponding all-time, all-sky searches. We find no evidence of a gravitational wave signal associated with any of the IPN GRBs in the sample, nor do we find evidence for a population of weak gravitational wave signals associated with the GRBs. For all IPN-detected GRBs, for which a sufficient duration of quality gravitational wave data are available, we place lower bounds on the distance to the source in accordance with an optimistic assumption of gravitational wave emission energy of 10(exp-2) solar mass c(exp 2) at 150 Hz, and find a median of 13 Mpc. For the 27 short-hard GRBs we place 90% confidence exclusion distances to two source models: a binary neutron star coalescence, with a median distance of 12 Mpc, or the coalescence of a neutron star and black hole, with a median distance of 22 Mpc. Finally, we combine this search with previously published results to provide a population statement for GRB searches in first-generation LIGO and Virgo gravitational wave detectors and a resulting examination of prospects for the advanced gravitational wave detectors.
Feasibility analysis of gravitational experiments in space
Everitt, C. W. F.
1977-01-01
Experiments on gravitation and general relativity suggested by different workers in the past ten or more years are reviewed, their feasibility examined, and the advantages of performing them in space were studied. The experiments include: (1) the gyro relativity experiment; (2) experiments to test the equivalence of gravitational and inertial mass; (3) an experiment to look for nongeodesic motion of spinning bodies in orbit around the earth; (4) experiments to look for changes of the gravitational constant G with time; (5) a variety of suggestions; laboratory tests of experimental gravity; and (6) gravitational wave experiments.
Possible role of torsion in gravitational theories
International Nuclear Information System (INIS)
Nieh, H.T.
1983-01-01
Torsion is of interest in an indirect way, in that it has the potential of being an important ingredient in a future successful quantum theory of gravitation. Einstein's theory of gravitation, despite its simplicity and elegance, and its successes in large-scale gravitational phenomena, can only be regarded as a macroscopic classical theory. It is a non-renormalizable quantum field theory, and, therefore, lacks the status of a good microscopic theory. It is the search for a successful quantum field theory of gravitation that poses as one of the great challenges to theoretical physics today. (Auth.)
Physics, Astrophysics and Cosmology with Gravitational Waves
Directory of Open Access Journals (Sweden)
Sathyaprakash B. S.
2009-03-01
Full Text Available Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers, and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.
Observing a Gravitational Wave Background With Lisa
National Research Council Canada - National Science Library
Tinto, M; Armstrong, J; Estabrook, F
2000-01-01
... formation of several observables. All are independent of lasers and frequency standard phase fluctuations, but have different couplings to gravitational waves and to the various LISA instrumental noises...
Physics, Astrophysics and Cosmology with Gravitational Waves.
Sathyaprakash, B S; Schutz, Bernard F
2009-01-01
Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.
Gravitational Wave Astrophysics: Opening the New Frontier
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.
Actuality of the Einstein theory of gravitation
International Nuclear Information System (INIS)
Ivanenko, D.D.
1982-01-01
Problems of actuality of the Einstein theory of gravitation are lightened. The great Einstein theory of gravitation is shown to remain a reliable base of understanding of modern physical world pattern and its inevitable further inexhaustible precising. The main GRT difficulties are enumirated: determination of reference systems, presence of singularities in the theory, absence of consistent determination of the gravity energy, impossibility of accounting the relations between atomic, gravitational and cosmological characteristics. The attention is paid to gauge, twistor problems and to unified interaction theory. The great contribution of the soviet science in the theory of gravitation is stressed
Astrophysical Gravitational Wave Sources Literature Catalog
National Aeronautics and Space Administration — Numerically-generated gravitational waveforms for circular inspiral into Kerr black holes. These waveforms were developed using Scott Hughes' black hole perturbation...
Effect of Earth gravitational field on the detection of gravitational waves
International Nuclear Information System (INIS)
Denisov, V.I.; Eliseev, V.A.
1987-01-01
Results of laboratory detection of high-frequency gravitational waves from the view point of gravitation theories formulated on the basis of pseudoeuclidean space-time are calculated. Peculiarities due to different effects of the Earth gravitational field on the rates of gravitational and electromagnetic wave propagation in these theories are analysed. Experiments on check of predictions of the given class of theories are suggested
The Scales of Gravitational Lensing
Directory of Open Access Journals (Sweden)
Francesco De Paolis
2016-03-01
Full Text Available After exactly a century since the formulation of the general theory of relativity, the phenomenon of gravitational lensing is still an extremely powerful method for investigating in astrophysics and cosmology. Indeed, it is adopted to study the distribution of the stellar component in the Milky Way, to study dark matter and dark energy on very large scales and even to discover exoplanets. Moreover, thanks to technological developments, it will allow the measure of the physical parameters (mass, angular momentum and electric charge of supermassive black holes in the center of ours and nearby galaxies.
Testing Fundamental Gravitation in Space
Energy Technology Data Exchange (ETDEWEB)
Turyshev, Slava G.
2013-10-15
General theory of relativity is a standard theory of gravitation; as such, it is used to describe gravity when the problems in astronomy, astrophysics, cosmology, and fundamental physics are concerned. The theory is also relied upon in many modern applications involving spacecraft navigation, geodesy, and time transfer. Here we review the foundations of general relativity and discuss its current empirical status. We describe both the theoretical motivation and the scientific progress that may result from the new generation of high-precision tests that are anticipated in the near future.
Moduli destabilization via gravitational collapse
Energy Technology Data Exchange (ETDEWEB)
Hwang, Dong-il [Sogang Univ., Seoul (Korea, Republic of). Center for Quantum Spacetime; Pedro, Francisco G. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany). Theory Group; Yeom, Dong-han [Sogang Univ., Seoul (Korea, Republic of). Center for Quantum Spacetime; Kyoto Univ. (Japan). Yukawa Inst. for Theoretical Physics
2013-06-15
We examine the interplay between gravitational collapse and moduli stability in the context of black hole formation. We perform numerical simulations of the collapse using the double null formalism and show that the very dense regions one expects to find in the process of black hole formation are able to destabilize the volume modulus. We establish that the effects of the destabilization will be visible to an observer at infinity, opening up a window to a region in spacetime where standard model's couplings and masses can differ significantly from their background values.
General definition of gravitational tension
International Nuclear Information System (INIS)
Harmark, T.; Obers, N.A.
2004-01-01
In this note we give a general definition of the gravitational tension in a given asymptotically translationally-invariant spatial direction of a space-time. The tension is defined via the extrinsic curvature in analogy with the Hawking-Horowitz definition of energy. We show the consistency with the ADM tension formulas for asymptotically-flat space-times, in particular for Kaluza-Klein black hole solutions. Moreover, we apply the general tension formula to near-extremal branes, constituting a check for non-asymptotically flat space-times. (author)
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 field of relativistic gyratons
Energy Technology Data Exchange (ETDEWEB)
Frolov, Valeri P [Theoretical Physics Institute, Department of Physics, University of Alberta, Edmonton, AB, T6G 2J1 (Canada)
2007-05-15
A gyraton is an object moving with the speed of light and having finite energy and internal angular momentum (spin). First we derive the gravitational field of a gyraton in the linear approximation. After this we study solutions of the vacuum Einstein equations for gyratons. We demonstrate that these solutions in 4 and higher dimensions reduce to two linear problems in a Euclidean space. A similar reduction is also valid for gyraton solutions of the Einstein-Maxwell gravity and in supergravity. Namely, we demonstrate that in the both cases the solutions in 4 and higher dimensions reduce to linear problems in a Euclidean space.
Gravitational polarizability of black holes
International Nuclear Information System (INIS)
Damour, Thibault; Lecian, Orchidea Maria
2009-01-01
The gravitational polarizability properties of black holes are compared and contrasted with their electromagnetic polarizability properties. The 'shape' or 'height' multipolar Love numbers h l of a black hole are defined and computed. They are then compared to their electromagnetic analogs h l EM . The Love numbers h l give the height of the lth multipolar 'tidal bulge' raised on the horizon of a black hole by faraway masses. We also discuss the shape of the tidal bulge raised by a test-mass m, in the limit where m gets very close to the horizon.
Radiatively-induced gravitational leptogenesis
Directory of Open Access Journals (Sweden)
J.I. McDonald
2015-12-01
Full Text Available We demonstrate how loop effects in gravitational backgrounds lead to a difference in the propagation of matter and antimatter, and show this is forbidden in flat space due to CPT and translation invariance. This mechanism, which is naturally present in beyond the standard model (BSM theories exhibiting C and CP violation, generates a curvature-dependent chemical potential for leptons in the low-energy effective Lagrangian, allowing a matter–antimatter asymmetry to be generated in thermodynamic equilibrium, below the BSM scale.
Review on possible gravitational anomalies
International Nuclear Information System (INIS)
Amador, Xavier E
2005-01-01
This is an updated introductory review of 2 possible gravitational anomalies that has attracted part of the Scientific community: the Allais effect that occur during solar eclipses, and the Pioneer 10 spacecraft anomaly, experimented also by Pioneer 11 and Ulysses spacecrafts. It seems that, to date, no satisfactory conventional explanation exist to these phenomena, and this suggests that possible new physics will be needed to account for them. The main purpose of this review is to announce 3 other new measurements that will be carried on during the 2005 solar eclipses in Panama and Colombia (Apr. 8) and in Portugal (Oct.15)
Prasanna, A R
2017-01-01
This book suitable for post graduates in Physics and Astrophysics aims at introducing the theory of general relativity as an important background for doing astrophysics. Starting from a detailed discussion of the various mathematical concepts for doing general relativity, the book introduces the geometric description of gravity. It gives a brief historical perspective to classical mechanics and electrodynamics making an attempt to establish the necessity of special relativity as propounded by Einstein extending to General Relativity. This book is a good starting point for post graduates wanting to pursue the modern topics of Cosmology, High energy astrophysics and related areas.
BOOK REVIEW: Gravitational Waves, Volume 1: Theory and Experiments
Poisson, Eric
2008-10-01
driven by radiative losses, the frequency spectrum of the radiation, and the dependence of the waveforms on cosmological parameters. In chapter 5 the author tackles a challenging topic: the post-Newtonian theory of gravitational-wave generation, mostly as developed by Luc Blanchet and his collaborators. This topic is extremely demanding, and the author does a good job of describing the main ideas and summarizing the main results. The presentation is detailed, but it is descriptive rather than didactic; this is appropriate, since a systematic development of this topic would surely require an entire book (or two, or three). In chapter 6, which concludes part I of the book, the author discusses the observational confirmation of the existence of gravitational waves that came from a handful of binary pulsars. He provides a detailed derivation of the timing formula that relates each pulse's time-of-arrival to the system's orbital parameters. Measurement of these parameters produce strongly constraining tests of general relativity, and it is the accurate determination of the slowly decreasing orbital period that led to the inescapable conclusion that gravitational waves do, in fact, exist. Part II of the book is devoted to the experimental aspects of gravitational waves: how the detectors work, and how the weak signals are extracted from the noisy data streams. In chapter 7 the author provides a solid introduction to data-analysis techniques, which include the characterization of detector noise by a spectral density function, the matched filtering of signals of known form, and the statistical theory of signal detection and parameter estimation. This last topic is beautifully covered; the author introduces both frequentist and Bayesian views of probabilities, and he (correctly) favours the Bayesian approach to determine the probability distribution function of signal parameters, given the detector's output data. The theory is applied to many types of signals: short bursts
Computer-games for gravitational wave science outreach: Black Hole Pong and Space Time Quest
International Nuclear Information System (INIS)
Carbone, L; Bond, C; Brown, D; Brückner, F; Grover, K; Lodhia, D; Mingarelli, C M F; Fulda, P; Smith, R J E; Unwin, R; Vecchio, A; Wang, M; Whalley, L; Freise, A
2012-01-01
We have established a program aimed at developing computer applications and web applets to be used for educational purposes as well as gravitational wave outreach activities. These applications and applets teach gravitational wave physics and technology. The computer programs are generated in collaboration with undergraduates and summer students as part of our teaching activities, and are freely distributed on a dedicated website. As part of this program, we have developed two computer-games related to gravitational wave science: 'Black Hole Pong' and 'Space Time Quest'. In this article we present an overview of our computer related outreach activities and discuss the games and their educational aspects, and report on some positive feedback received.
Interaction of gravitational waves with superconductors
Energy Technology Data Exchange (ETDEWEB)
Inan, N.A.; Thompson, J.J. [University of California, Schools of Natural Sciences, Merced, CA (United States); Chiao, R.Y. [University of California, Schools of Natural Sciences and Engineering, Merced, CA (United States)
2017-06-15
Applying the Helmholtz Decomposition theorem to linearized General Relativity leads to a gauge-invariant formulation where the transverse-traceless part of the metric perturbation describes gravitational waves in matter. Gravitational waves incident on a superconductor can be described by a linear London-like constituent equation characterized by a ''gravitational shear modulus'' and a corresponding plasma frequency and penetration depth. Electric-like and magnetic-like gravitational tensor fields are defined in terms of the strain field of a gravitational wave. It is shown that in the DC limit, the magnetic-like tensor field is expelled from the superconductor in a gravitational Meissner-like effect. The Cooper pair density is described by the Ginzburg-Landau theory embedded in curved space-time. The ionic lattice is modeled by quantum harmonic oscillators coupled to gravitational waves and characterized by quasi-energy eigenvalues for the phonon modes. The formulation predicts the possibility of a dynamical Casimir effect since the zero-point energy of the ionic lattice phonons is found to be modulated by the gravitational wave, in a quantum analog of a ''Weber-bar effect.'' Applying periodic thermodynamics and the Debye model in the low-temperature limit leads to a free energy density for the ionic lattice. Lastly, we relate the gravitational strain of space to the strain of matter to show that the response to a gravitational wave is far less for the Cooper pair density than for the ionic lattice. This predicts a charge separation effect in the superconductor as a result of the gravitational wave. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Gravitational waves from axion monodromy
Energy Technology Data Exchange (ETDEWEB)
Hebecker, Arthur; Jaeckel, Joerg; Rompineve, Fabrizio; Witkowski, Lukas T. [Institute for Theoretical Physics, University of Heidelberg,Philosophenweg 19, 69120 Heidelberg (Germany)
2016-11-02
Large field inflation is arguably the simplest and most natural variant of slow-roll inflation. Axion monodromy may be the most promising framework for realising this scenario. As one of its defining features, the long-range polynomial potential possesses short-range, instantonic modulations. These can give rise to a series of local minima in the post-inflationary region of the potential. We show that for certain parameter choices the inflaton populates more than one of these vacua inside a single Hubble patch. This corresponds to a dynamical phase decomposition, analogously to what happens in the course of thermal first-order phase transitions. In the subsequent process of bubble wall collisions, the lowest-lying axionic minimum eventually takes over all space. Our main result is that this violent process sources gravitational waves, very much like in the case of a first-order phase transition. We compute the energy density and peak frequency of the signal, which can lie anywhere in the mHz-GHz range, possibly within reach of next-generation interferometers. We also note that this “dynamical phase decomposition' phenomenon and its gravitational wave signal are more general and may apply to other inflationary or reheating scenarios with axions and modulated potentials.
On the Induced Gravitational Collapse
Directory of Open Access Journals (Sweden)
M. Becerra Laura
2018-01-01
Full Text Available The induced gravitational collapse (IGC paradigm has been applied to explain the long gamma ray burst (GRB associated with type Ic supernova, and recently the Xray flashes (XRFs. The progenitor is a binary systems of a carbon-oxygen core (CO and a neutron star (NS. The CO core collapses and undergoes a supernova explosion which triggers the hypercritical accretion onto the NS companion (up to 10-2 M⊙s-1. For the binary driven hypernova (BdHNe, the binary system is enough bound, the NS reach its critical mass, and collapse to a black hole (BH with a GRB emission characterized by an isotropic energy Eiso > 1052 erg. Otherwise, for binary systems with larger binary separations, the hypercritical accretion onto the NS is not sufficient to induced its gravitational collapse, a X-ray flash is produced with Eiso < 1052 erg. We’re going to focus in identify the binary parameters that limits the BdHNe systems with the XRFs systems.
Relativity in Combinatorial Gravitational Fields
Directory of Open Access Journals (Sweden)
Mao Linfan
2010-04-01
Full Text Available A combinatorial spacetime $(mathscr{C}_G| uboverline{t}$ is a smoothly combinatorial manifold $mathscr{C}$ underlying a graph $G$ evolving on a time vector $overline{t}$. As we known, Einstein's general relativity is suitable for use only in one spacetime. What is its disguise in a combinatorial spacetime? Applying combinatorial Riemannian geometry enables us to present a combinatorial spacetime model for the Universe and suggest a generalized Einstein gravitational equation in such model. Forfinding its solutions, a generalized relativity principle, called projective principle is proposed, i.e., a physics law ina combinatorial spacetime is invariant under a projection on its a subspace and then a spherically symmetric multi-solutions ofgeneralized Einstein gravitational equations in vacuum or charged body are found. We also consider the geometrical structure in such solutions with physical formations, and conclude that an ultimate theory for the Universe maybe established if all such spacetimes in ${f R}^3$. Otherwise, our theory is only an approximate theory and endless forever.
Tourrenc, Philippe
1992-01-01
La relativité générale a cessé d'être une pure théorie justifiée par les "trois tests classiques" disponibles il y a trente ans. Des pulsars, vrais laboratoires de gravitation relativiste, ont été découverts et étudiés. A l'automne 1991 les Etats-Unis ont pris la décision de construire deux détecteurs interférométriques d'ondes gravitationnelles. Au début de l'été 1992, le ministre français de la Recherche et de l'Espace a pris un engagement de même nature concernant le projet VIRGO, projet franco-italien de construction d'une antenne interférométrique. La gravitation relativiste est devenue un riche domaine d'observation et d'expérimentation. Cet ouvrage est un manuel de physique dont les intentions et le contenu se veulent adaptés au contexte scientifique actuel. Il doit beaucoup aux divers enseignements donnés par l'auteur, principalement l'enseignement de relativité générale en maîtrise de physique à l'université Pierre et Marie Curie (Paris VI). Dans la première partie, l...
Curvature bound from gravitational catalysis
Gies, Holger; Martini, Riccardo
2018-04-01
We determine bounds on the curvature of local patches of spacetime from the requirement of intact long-range chiral symmetry. The bounds arise from a scale-dependent analysis of gravitational catalysis and its influence on the effective potential for the chiral order parameter, as induced by fermionic fluctuations on a curved spacetime with local hyperbolic properties. The bound is expressed in terms of the local curvature scalar measured in units of a gauge-invariant coarse-graining scale. We argue that any effective field theory of quantum gravity obeying this curvature bound is safe from chiral symmetry breaking through gravitational catalysis and thus compatible with the simultaneous existence of chiral fermions in the low-energy spectrum. With increasing number of dimensions, the curvature bound in terms of the hyperbolic scale parameter becomes stronger. Applying the curvature bound to the asymptotic safety scenario for quantum gravity in four spacetime dimensions translates into bounds on the matter content of particle physics models.
Schuyler, Dean
2005-01-01
本書を著したHornbyは英国のソーシャルワーカーである。彼女は1983年に｢Collaboration in social work(Journal of social work practice,1.1)｣を発表し、ソーシャルワークでの職種間の連携の重要性について報告している。さらに1993年に発刊した本書では、同一機関内の人間関係 ...
A distinguishing gravitational property for gravitational equation in higher dimensions
International Nuclear Information System (INIS)
Dadhich, Naresh
2016-01-01
It is well known that Einstein gravity is kinematic (meaning that there is no non-trivial vacuum solution; i.e. the Riemann tensor vanishes whenever the Ricci tensor does so) in 3 dimension because the Riemann tensor is entirely given in terms of the Ricci tensor. Could this property be universalized for all odd dimensions in a generalized theory? The answer is yes, and this property uniquely singles out pure Lovelock (it has only one Nth order term in the action) gravity for which the Nth order Lovelock-Riemann tensor is indeed given in terms of the corresponding Ricci tensor for all odd, d = 2N + 1, dimensions. This feature of gravity is realized only in higher dimensions and it uniquely picks out pure Lovelock gravity from all other generalizations of Einstein gravity. It serves as a good distinguishing and guiding criterion for the gravitational equation in higher dimensions. (orig.)
A distinguishing gravitational property for gravitational equation in higher dimensions
Dadhich, Naresh
2016-03-01
It is well known that Einstein gravity is kinematic (meaning that there is no non-trivial vacuum solution; i.e. the Riemann tensor vanishes whenever the Ricci tensor does so) in 3 dimension because the Riemann tensor is entirely given in terms of the Ricci tensor. Could this property be universalized for all odd dimensions in a generalized theory? The answer is yes, and this property uniquely singles out pure Lovelock (it has only one Nth order term in the action) gravity for which the Nth order Lovelock-Riemann tensor is indeed given in terms of the corresponding Ricci tensor for all odd, d=2N+1, dimensions. This feature of gravity is realized only in higher dimensions and it uniquely picks out pure Lovelock gravity from all other generalizations of Einstein gravity. It serves as a good distinguishing and guiding criterion for the gravitational equation in higher dimensions.
Stability of merons in gravitational models
International Nuclear Information System (INIS)
Akdeniz, K.G.; Hacinliyan, A.; Kalayci, J.
1982-11-01
The stability properties of merons are investigated in gravitational models by taking the DeAFF model as a theoretical laboratory. We find that in gravitational models containing Yang-Mills fields merons are unstable. Stability might be possible in N=4 supergravity models with Asub(μ)=0. (author)
Gravitational Metric Tensor Exterior to Rotating Homogeneous ...
African Journals Online (AJOL)
The covariant and contravariant metric tensors exterior to a homogeneous spherical body rotating uniformly about a common φ axis with constant angular velocity ω is constructed. The constructed metric tensors in this gravitational field have seven non-zero distinct components.The Lagrangian for this gravitational field is ...
Inertial reference frames and gravitational forces
International Nuclear Information System (INIS)
Santavy, I.
1981-01-01
The connection between different definitions of inertial, i.e. fundamental, reference frames and the corresponding characterisation of gravitational fields by gravitational forces are considered from the point of view of their possible interpretation in university introductory courses. The introduction of a special class of reference frames, denoted 'mixed reference frames' is proposed and discussed. (author)
How Spherical Is a Cube (Gravitationally)?
Sanny, Jeff; Smith, David
2015-01-01
An important concept that is presented in the discussion of Newton's law of universal gravitation is that the gravitational effect external to a spherically symmetric mass distribution is the same as if all of the mass of the distribution were concentrated at the center. By integrating over ring elements of a spherical shell, we show that the…
Neutrino bursts and gravitational waves experiments
Energy Technology Data Exchange (ETDEWEB)
Castagnoli, C; Galeotti, P; Saavedra, O [Consiglio Nazionale delle Ricerche, Turin (Italy). Lab. di Cosmo-Geofisica
1978-05-01
Several experiments have been performed in many countries to observe gravitational waves or neutrino bursts. Since their simultaneous emission may occur in stellar collapse, the authors evaluate the effect of neutrino bursts on gravitational wave antennas and suggest the usefulness of a time correlation among the different detectors.
Amplification caused by gravitational bending of light
International Nuclear Information System (INIS)
Schneider, P.
1985-01-01
Gravitational bending of light may not only lead to multiple imaging (gravitational lens effect), but also affects the apparent luminosity of a source. It is shown here that a mass distribution near the line-of-sight to any source always increases the observable flux relative to the case in which the deflector is absent
On the field theoretic description of gravitation
Nieuwenhuizen, T.M.; Kleinert, H.; Jantzen, R.T.; Ruffini, R.
2008-01-01
Maxwell started to describe gravitation as a field in Minkowski space. Such an approach brought Babak and Grishchuk in 1999 the gravitational energy-momentum tensor. Simple manipulations allow the Einstein equations to take the form Aµν = (8πG/c4)Θµν, where A is the acceleration tensor and Θ, the
Gravitational consequences of modern field theories
Horowitz, Gary T.
1989-01-01
Some gravitational consequences of certain extensions of Einstein's general theory of relativity are discussed. These theories are not alternative theories of gravity in the usual sense. It is assumed that general relativity is the appropriate description of all gravitational phenomena which were observed to date.
Self-gravitation in Saturn's rings
International Nuclear Information System (INIS)
Salo, H.; Lukkari, J.
1982-01-01
In a ring-shaped collisional system self-gravitation reduces the equilibrium values of the geometric and optical thickness. In Saturn's rings both effects are appreciable. The previously found discrepancy between the calculated profile and the observed profile of the rings is chiefly caused by the omission of self-gravitation. (Auth.)
Geodesics analysis of colliding gravitational shock waves
International Nuclear Information System (INIS)
Pozdeeva, E.
2011-01-01
Full text: (author)We consider collision of charged gravitational shock waves with infinite transverse extension (charged gravitational walls). We study the influence of the charges on the trapped surface formation in the charged walls collision. This consideration has applications in the in heavy ion collisions using a holographic approach in which the charge plays the role of the chemical potential
Gravitational Waves from Oscillons with Cuspy Potentials.
Liu, Jing; Guo, Zong-Kuan; Cai, Rong-Gen; Shiu, Gary
2018-01-19
We study the production of gravitational waves during oscillations of the inflaton around the minimum of a cuspy potential after inflation. We find that a cusp in the potential can trigger copious oscillon formation, which sources a characteristic energy spectrum of gravitational waves with double peaks. The discovery of such a double-peak spectrum could test the underlying inflationary physics.
Gravitational waves from binary black holes
Indian Academy of Sciences (India)
It is almost a century since Einstein predicted the existence of gravitational waves as one of the consequences of his general theory of relativity. A brief historical overview including Chandrasekhar's contribution to the subject is ﬁrst presented. The current status of the experimental search for gravitational waves and the ...
Physics of interferometric gravitational wave detectors
Indian Academy of Sciences (India)
The Caltech-MIT joint LIGO project is operating three long-baseline interferometers (one of 2 km and two of 4 km) in order to unambiguously measure the infinitesimal displacements of isolated test masses which convey the signature of gravitational waves from astrophysical sources. An interferometric gravitational wave ...
Workshop on gravitational waves and relativistic astrophysics
Indian Academy of Sciences (India)
Discussions related to gravitational wave experiments viz. LIGO and LISA as well as to observations of supermassive black holes dominated the workshop sessions on gravitational waves and relativistic astrophysics in the ICGC-2004. A summary of seven papers that were presented in these workshop sessions has been ...
Holographic entanglement entropy and gravitational anomalies
Castro, A.; Detournay, S.; Iqbal, N.; Perlmutter, E.
2014-01-01
We study entanglement entropy in two-dimensional conformal field theories with a gravitational anomaly. In theories with gravity duals, this anomaly is holographically represented by a gravitational Chern-Simons term in the bulk action. We show that the anomaly broadens the Ryu-Takayanagi minimal
Observing a Gravitational Wave Background With Lisa
National Research Council Canada - National Science Library
Tinto, M; Armstrong, J; Estabrook, F
2000-01-01
.... Comparison of the conventional Michelson interferometer observable with the fully-symmetric Sagnac data-type allows unambiguous discrimination between a gravitational wave background and instrumental noise. The method presented here can be used to detect a confusion-limited gravitational wave background.
A generalized variational principle of gravitation
International Nuclear Information System (INIS)
El-Tahir, A.
1987-09-01
Generalized fourth order differential equations of gravitation are derived. Though similar to those earlier obtained by Lanczos, the present derivation is based on more general assumptions. The geometry-gravity dualism is discussed and the nonlinearity of gravitation is shown to be constrained by the curvature of space. (author). 5 refs
Gravitational radiation and 3D numerical relativity
International Nuclear Information System (INIS)
Nakamura, T.
1986-01-01
Study of Numerical Relativity in Kyoto is reviewed. Main topics discussed are 2D rotating collapse, phase cancellation effects and perturbation calculation of the gravitational radiation from a particle falling into a black hole. New numerical results on 3D time evolution of pure gravitational waves are also presented
Gravitational bending of light rays in plasma
International Nuclear Information System (INIS)
Tsupko, O. Yu.; Bisnovatyi-Kogan, G. S.
2010-01-01
We investigate the gravitational lensing effect in presence of plasma. We observe that in a homogeneous plasma the gravitational deflection angle differs from that in vacuum, and it depends on the frequency of the photon. We discuss observational consequences of this dependence for the point-mass lensing and estimate possibility of the observation of this effect by the planned project Radioastron.
Astronomers Get New Tools for Gravitational-Wave Detection
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
Can JWST Follow Up on Gravitational-Wave Detections?
Kohler, Susanna
2016-02-01
SearchIntegration time needed for JWSTs NIRCam to detect a kilonova at 200 Mpc, as a function of time since the merger. Different curves correspond to different NIRCam filters. Note that the total time for follow-up is overwhelmingly dominated by things like telescope slew time, rather than by this exposure time. [Bartos et al. 2016]In a recent study, a team of authors led by Imre Bartos (Columbia University) evaluatewhether JWST will be capable of catching these kilonovae if LIGO finds gravitational wave signals.Bartos and collaborators calculate that, given the sensitivity of the different filters on JWSTs Near-Infrared Camera, the instrument should easily be able to detect a kilonova 200 Mpc away (a typical distance at which LIGO might be able to find a neutron-star binary). But theres a catch: 10 deg2 is a really big sky area, and it would take JWST an unfeasible amount of time (days!) to fully cover it.The authors suggest insteadusing a targeted search. Since most mergers are expected to be in or near galaxies, JWST could specifically focus the follow-up search on known galaxies within the searcharea. This approach would bring the total search time down to 12.6 hours, which is within the realm of feasibility. And this time could be reduced even further by concentrating on galaxies most likely to host kilonovae, like those with high star-formation rates.The conclusion: if LIGO is able to detect gravitational waves, JWST will provide an excellent means to follow up on the detection in the attempt toidentify the source.CitationI. Bartos et al 2016 ApJ 816 61. doi:10.3847/0004-637X/816/2/61
Microcanonical functional integral for the gravitational field
International Nuclear Information System (INIS)
Brown, J.D.; York, J.W. Jr.
1993-01-01
The gravitational field in a spatially finite region is described as a microcanonical system. The density of states ν is expressed formally as a functional integral over Lorentzian metrics and is a functional of the geometrical boundary data that are fixed in the corresponding action. These boundary data are the thermodynamical extensive variables, including the energy and angular momentum of the system. When the boundary data are chosen such that the system is described semiclassically by any real stationary axisymmetric black hole, then in this same approximation lnν is shown to equal 1/4 the area of the black-hole event horizon. The canonical and grand canonical partition functions are obtained by integral transforms of ν that lead to ''imaginary-time'' functional integrals. A general form of the first law of thermodynamics for stationary black holes is derived. For the simpler case of nonrelativistic mechanics, the density of states is expressed as a real-time functional integral and then used to deduce Feynman's imaginary-time functional integral for the canonical partition function
Gravitational Mass, Its Mechanics - What It Is; How It Operates
Ellman, Roger
1999-01-01
The earlier paper, Inertial Mass, Its Mechanics - What It Is; How It Operates, developed the mechanics of inertial mass. The present paper is for the purpose of equivalently developing gravitation. The behavior of gravitation is well known, as described by Newton's Law of Gravitation. But just what gravitational mass is, how gravitational behavior comes about, what in material reality produces the effects of gravitational mass, has been little understood. The only extant hypotheses involve th...
Black-Hole Binaries, Gravitational Waves, and Numerical Relativity
Kelly, Bernard J.; Centrella, Joan; Baker, John G.; Kelly, Bernard J.; vanMeter, James R.
2010-01-01
Understanding the predictions of general relativity for the dynamical interactions of two black holes has been a long-standing unsolved problem in theoretical physics. Black-hole mergers are monumental astrophysical events ' releasing tremendous amounts of energy in the form of gravitational radiation ' and are key sources for both ground- and spacebased gravitational wave detectors. The black-hole merger dynamics and the resulting gravitational waveforms can only he calculated through numerical simulations of Einstein's equations of general relativity. For many years, numerical relativists attempting to model these mergers encountered a host of problems, causing their codes to crash after just a fraction of a binary orbit cnuld be simulated. Recently ' however, a series of dramatic advances in numerical relativity has ' for the first time, allowed stable / robust black hole merger simulations. We chronicle this remarkable progress in the rapidly maturing field of numerical relativity, and the new understanding of black-hole binary dynamics that is emerging. We also discuss important applications of these fundamental physics results to astrophysics, to gravitationalwave astronomy, and in other areas.
Estimation of the gravitational wave polarizations from a nontemplate search
Di Palma, Irene; Drago, Marco
2018-01-01
Gravitational wave astronomy is just beginning, after the recent success of the four direct detections of binary black hole (BBH) mergers and the first observation from a binary neutron star inspiral, with the expectation of many more events to come. Given the possibility to detect waves from not exactly modeled astrophysical processes, it is fundamental to be ready to calculate the polarization waveforms in the case of searches using nontemplate algorithms. In such a case, the waveform polarizations are the only quantities that contain direct information about the generating process. We present the performance of a new valuable tool to estimate the inverse solution of gravitational wave transient signals, starting from the analysis of the signal properties of a nontemplate algorithm that is open to a wider class of gravitational signals not covered by template algorithms. We highlight the contributions to the wave polarization associated with the detector response, the sky localization, and the polarization angle of the source. In this paper we present the performances of such a method and its implications by using two main classes of transient signals, resembling the limiting case for most simple and complicated morphologies. The performances are encouraging for the tested waveforms: the correlation between the original and the reconstructed waveforms spans from better than 80% for simple morphologies to better than 50% for complicated ones. For a nontemplate search these results can be considered satisfactory to reconstruct the astrophysical progenitor.