79 research outputs found
A Blind Hierarchical Coherent Search for Gravitational-Wave Signals from Coalescing Compact Binaries in a Network of Interferometric Detectors
No full textWe describe a hierarchical data analysis pipeline for coherently searching for gravitational-wave signals from non-spinning compact binary coalescences (CBCs) in the data of multiple earth-based detectors. This search assumes no prior information on the sky position of the source or the time of occurrence of its transient signals and, hence, is termed 'blind'. The pipeline computes the coherent network search statistic that is optimal in stationary, Gaussian noise. More importantly, it allows for the computation of a suite of alternative multi-detector coherent search statistics and signal-based discriminators that can improve the performance of CBC searches in real data, which can be both non-stationary and non-Gaussian. Also, unlike the coincident multi-detector search statistics that have been employed so far, the coherent statistics are different in the sense that they check for the consistency of the signal amplitudes and phases in the different detectors with their different orientations and with the signal arrival times in them. Since the computation of coherent statistics entails searching in the sky, it is more expensive than that of the coincident statistics that do not require it. To reduce computational costs, the first stage of the hierarchical pipeline constructs coincidences of triggers from the multiple interferometers, by requiring their proximity in time and component masses. The second stage follows up on these coincident triggers by computing the coherent statistics. Here, we compare the performances of this hierarchical pipeline with and without the second (or coherent) stage in Gaussian noise. Although introducing hierarchy can be expected to cause some degradation in the detection efficiency compared to that of a single-stage coherent pipeline, nevertheless it improves the computational speed of the search considerably. The two main results of this work are as follows: (1) the performance of the hierarchical coherent pipeline on Gaussian data is shown to be better than the pipeline with just the coincident stage; (2) the three-site network of LIGO detectors, in Hanford and Livingston (USA), and Virgo detector in Cascina (Italy) cannot resolve the polarization of waves arriving from certain parts of the sky. This can cause the three-site coherent statistic at those sky positions to become singular. Regularized versions of the statistic can avoid that problem, but can be expected to be sub-optimal. The aforementioned improvement in the pipeline's performance due to the coherent stage is in spite of this handicap
Erratum: Search for gravitational waves from compact binary coalescence in LIGO and Virgo data from S5 and VSR1 (Physical Review D - Particles, Fields, Gravitation and Cosmology)
No full textThis paper was published online on 5 November 2010 with an omission in the Collaboration author list. S. Dwyer has
been added as of 12 April 2012. The Collaboration author list is incorrect in the printed version of the journal
Erratum: All-sky search for gravitational-wave bursts in the first joint LIGO-GEO-Virgo run (Physical Review D - Particles, Fields, Gravitation and Cosmology (2010) 81 (102001))
No full textThis paper was published online on 5 May 2010 with an omission in the Collaboration author list. S. Dwyer has been
added as of 12 April 2012. The Collaboration author list is incorrect in the printed version of the journal
Publisher's Note: Search for gravitational waves from binary black hole inspiral, merger, and ringdown
No full textThis paper was published online on 6 June 2011 with an omission in the Collaboration author list. S. Dwyer has been
added as of 12 April 2012. The Collaboration author list is incorrect in the printed version of the journal
Enhanced sensitivity of the LIGO gravitational wave detector by using squeezed states of light
No full textLIGO Scientific Collaboration members: J. Munch, D. J. Ottaway, P. J. Veitch for University of Adelaide.Nearly a century after Einstein first predicted the existence of gravitational waves, a global network of Earth-based gravitational wave observatories¹,²,³,⁴ is seeking to directly detect this faint radiation using precision laser interferometry. Photon shot noise, due to the quantum nature of light, imposes a fundamental limit on the attometre-level sensitivity of the kilometre-scale Michelson interferometers deployed for this task. Here, we inject squeezed states to improve the performance of one of the detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) beyond the quantum noise limit, most notably in the frequency region down to 150 Hz, critically important for several astrophysical sources, with no deterioration of performance observed at any frequency. With the injection of squeezed states, this LIGO detector demonstrated the best broadband sensitivity to gravitational waves ever achieved, with important implications for observing the gravitational-wave Universe with unprecedented sensitivity.The LIGO Scientific Collaboratio
Constraints on Cosmic Strings from the LIGO-Virgo Gravitational-Wave Detectors
No full textContains fulltext :
127856pub.pdf (Publisher’s version ) (Open Access)
Contains fulltext :
127856.pdf (Author’s version preprint ) (Open Access
Improved Upper Limits on the Stochastic Gravitational-Wave Background from 2009-2010 LIGO and Virgo Data
No full textGravitational waves from a variety of sources are predicted to superpose to create a stochastic background. This background is expected to contain unique information from throughout the history of the Universe that is unavailable through standard electromagnetic observations, making its study of fundamental importance to understanding the evolution of the Universe. We carry out a search for the stochastic background with the latest data from the LIGO and Virgo detectors. Consistent with predictions from most stochastic gravitational-wave background models, the data display no evidence of a stochastic gravitational-wave signal. Assuming a gravitational-wave spectrum of Omega(GW)(f) = Omega(alpha)(f/f(ref))(alpha), we place 95% confidence level upper limits on the energy density of the background in each of four frequency bands spanning 41.5-1726 Hz. In the frequency band of 41.5-169.25 Hz for a spectral index of alpha = 0, we constrain the energy density of the stochastic background to be Omega(GW)(f) < 5.6 x 10(-6). For the 600-1000 Hz band, Omega(GW)(f) < 0.14(f/900 Hz)(3), a factor of 2.5 lower than the best previously reported upper limits. We find Omega(GW)(f) < 1.8 x 10(-4) using a spectral index of zero for 170-600 Hz and Omega(GW)(f) < 1.0(f/1300 Hz)(3) for 1000-1726 Hz, bands in which no previous direct limits have been placed. The limits in these four bands are the lowest direct measurements to date on the stochastic background. We discuss the implications of these results in light of the recent claim by the BICEP2 experiment of the possible evidence for inflationary gravitational waves.U.S. National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen, GermanyItalian Istituto Nazionale di Fisica NucleareFrench Centre National de la Recherche ScientifiqueAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationNational Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationOTKA of HungaryScience and Technologies Funding Council of the UKLyon Institute of Origins (LIO)Alfred P. Sloan FoundationCALTECH, LIGO, Pasadena, CA 91125 USALouisiana State Univ, Baton Rouge, LA 70803 USAUniv Savoie, CNRS, IN2P3, LAPP, F-74941 Annecy Le Vieux, FranceIst Nazl Fis Nucl, Sez Napoli, I-80126 Naples, ItalyUniv Salerno, I-84084 Salerno, ItalyUniv Florida, Gainesville, FL 32611 USALivingston Observ, LIGO, Livingston, LA 70754 USACardiff Univ, Cardiff CF24 3AA, S Glam, WalesMax Planck Inst Gravitat Phys, Albert Einstein Inst, D-30167 Hannover, GermanyNikhef, NL-1098 XG Amsterdam, NetherlandsMIT, LIGO, Cambridge, MA 02139 USAInst Nacl Pesquisas Espaciais, BR-12227010 Sao Jose Dos Campos, SP, BrazilInteruniv Ctr Astron & Astrophys, Pune 411007, Maharashtra, IndiaTata Inst Fundamental Res, Bombay 400005, Maharashtra, IndiaSyracuse Univ, Syracuse, NY 13244 USAUniv Wisconsin, Milwaukee, WI 53201 USALeibniz Univ Hannover, D-30167 Hannover, GermanyIst Nazl Fis Nucl, Sez Pisa, I-56127 Pisa, ItalyUniv Siena, I-53100 Siena, ItalyStanford Univ, Stanford, CA 94305 USAUniv Mississippi, University, MS 38677 USACalif State Univ Fullerton, Fullerton, CA 92831 USAIst Nazl Fis Nucl, Sez Roma, I-00185 Rome, ItalyUniv Birmingham, Birmingham B15 2TT, W Midlands, EnglandMax Planck Inst Gravitat Phys, Albert Einstein Inst, D-14476 Golm, GermanyMontana State Univ, Bozeman, MT 59717 USAEGO, I-56021 Pisa, ItalyHanford Observ, LIGO, Richland, WA 99352 USAUniv Glasgow, SUPA, Glasgow G12 8QQ, Lanark, ScotlandUniv Paris Diderot, CEA Irfu, CNRS, IN2P3,APC,Observ Paris,Sorbonne Paris Cite, F-75205 Paris 13, FranceColumbia Univ, New York, NY 10027 USAUniv Pisa, I-56127 Pisa, ItalyCAMK PAN, PL-00716 Warsaw, PolandWarsaw Univ, Astron Observ, PL-00478 Warsaw, PolandIst Nazl Fis Nucl, Sez Genova, I-16146 Genoa, ItalyUniv Genoa, I-16146 Genoa, ItalySan Jose State Univ, San Jose, CA 95192 USAMoscow MV Lomonosov State Univ, Fac Phys, Moscow 119991, RussiaUniv Paris 11, CNRS, IN2P3, LAL, F-91898 Orsay, FranceNASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USAUniv Western Australia, Crawley, WA 6009, AustraliaRadboud Univ Nijmegen, IMAPP, Dept Astrophys, NL-6500 GL Nijmegen, NetherlandsUniv Nice Sophia Antipolis, CNRS, Observ Cote Azur, F-06304 Nice, FranceUniv Rennes 1, CNRS, Inst Phys Rennes, F-35042 Rennes, FranceUniv Lyon, CNRS, IN2P3, LMA, F-69622 Villeurbanne, FranceWashington State Univ, Pullman, WA 99164 USAIst Nazl Fis Nucl, Sez Perugia, I-06123 Perugia, ItalyIst Nazl Fis Nucl, Sez Firenze, I-50019 Florence, ItalyUniv Urbino Carlo Bo, I-61029 Urbino, ItalyUniv Oregon, Eugene, OR 97403 USAUniv Paris 06, CNRS, ENS, Lab Kastler Brossel, F-75005 Paris, FranceVrije Univ Amsterdam, NL-1081 HV Amsterdam, NetherlandsUniv Maryland, College Pk, MD 20742 USAUniv Massachusetts, Amherst, MA 01003 USAUniv Illes Balears, E-07122 Palma de Mallorca, SpainUniv Naples Federico II, I-80126 Naples, ItalyUniv Toronto, Canadian Inst Theoret Astrophys, Toronto, ON M5S 3H8, CanadaTsinghua Univ, Beijing 100084, Peoples R ChinaUniv Michigan, Ann Arbor, MI 48109 USARochester Inst Technol, Rochester, NY 14623 USAIst Nazl Fis Nucl, Sez Roma Tor Vergata, I-00133 Rome, ItalyNatl Tsing Hua Univ, Hsinchu 300, TaiwanCharles Sturt Univ, Wagga Wagga, NSW 2678, AustraliaCALTECH, CaRT, Pasadena, CA 91125 USAPusan Natl Univ, Pusan 609735, South KoreaAustralian Natl Univ, Canberra, ACT 0200, AustraliaCarleton Coll, Northfield, MN 55057 USAIst Nazl Fis Nucl, Gran Sasso Sci Inst, I-67100 Laquila, ItalyUniv Roma Tor Vergata, I-00133 Rome, ItalyUniv Roma La Sapienza, I-00185 Rome, ItalyUniv Brussels, B-1050 Brussels, BelgiumSonoma State Univ, Rohnert Pk, CA 94928 USAEmbry Riddle Aeronaut Univ, Prescott, AZ 86301 USAGeorge Washington Univ, Washington, DC 20052 USAUniv Cambridge, Cambridge CB2 1TN, EnglandNorthwestern Univ, Evanston, IL 60208 USAUniv Minnesota, Minneapolis, MN 55455 USAUniv Texas Brownsville, Brownsville, TX 78520 USAUniv Sheffield, Sheffield S10 2TN, S Yorkshire, EnglandRMKI, Wigner RCP, H-1121 Budapest, HungaryUniv Sannio Benevento, I-82100 Benevento, ItalyIst Nazl Fis Nucl, Grp Collegato Trento, I-38050 Trento, ItalyUniv Trent, I-38050 Trento, ItalyMontclair State Univ, Montclair, NJ 07043 USAPenn State Univ, University Pk, PA 16802 USAMTA Eotvos Univ, Lendulet Astrophys Res Grp, H-1117 Budapest, HungaryUniv Perugia, I-06123 Perugia, ItalyRutherford Appleton Lab, HSIC, Didcot OX11 0QX, Oxon, EnglandPerimeter Inst Theoret Phys, Waterloo, ON N2L 2Y5, CanadaAmer Univ, Washington, DC 20016 USAUniv Adelaide, Adelaide, SA 5005, AustraliaRaman Res Inst, Bangalore 560080, Karnataka, IndiaKorea Inst Sci & Technol Informat, Taejon 305806, South KoreaBialystok Univ, PL-15424 Bialystok, PolandUniv Southampton, Southampton SO17 1BJ, Hants, EnglandIISER TVM, Trivandrum 695016, Kerala, IndiaInst Appl Phys, Nizhnii Novgorod 603950, RussiaSeoul Natl Univ, Seoul 151742, South KoreaHanyang Univ, Seoul 133791, South KoreaIM PAN, PL-00956 Warsaw, PolandNCBJ, PL-05400 Otwock, PolandInst Plasma Res, Bhat 382428, Gandhinagar, IndiaUniv Melbourne, Parkville, Vic 3010, AustraliaIst Nazl Fis Nucl, Sez Padova, I-35131 Padua, ItalyMonash Univ, Clayton, Vic 3800, AustraliaUniv Strathclyde, SUPA, Glasgow G1 1XQ, Lanark, ScotlandCNRS, ESPCI, F-75005 Paris, FranceArgentinian Gravitat Wave Grp, RA-5000 Cordoba, ArgentinaUniv Camerino, Dipartimento Fis, I-62032 Camerino, ItalyUniv Texas Austin, Austin, TX 78712 USASouthern Univ & A&M Coll, Baton Rouge, LA 70813 USAColl William & Mary, Williamsburg, VA 23187 USAIISER Kolkata, Mohanpur 741252, W Bengal, IndiaNatl Inst Mat Sci, Taejon 305390, South KoreaHobart & William Smith Coll, Geneva, NY 14456 USARRCAT, Indore 452013, Madhya Pradesh, IndiaUniv West Scotland, SUPA, Paisley PA1 2BE, Renfrew, ScotlandInst Astron, PL-65265 Zielona Gora, PolandIndian Inst Technol, Ahmadabad 382424, Gujarat, IndiaUniv Estadual Paulista, Int Ctr Theoret Phys, Inst Fis Teor, South Amer Inst Res, BR-01140070 Sao Paulo, BrazilAndrews Univ, Berrien Springs, MI 49104 USATrinity Univ, San Antonio, TX 78212 USAUniv Washington, Seattle, WA 98195 USASE Louisiana Univ, Hammond, LA 70402 USAAbilene Christian Univ, Abilene, TX 79699 USAUniv Estadual Paulista, Int Ctr Theoret Phys, Inst Fis Teor, South Amer Inst Res, BR-01140070 Sao Paulo, Brazi
Multimessenger search for sources of gravitational waves and high-energy neutrinos: Initial results for LIGO-Virgo and IceCube
No full textWe report the results of a multimessenger search for coincident signals from the LIGO and Virgo gravitational-wave observatories and the partially completed IceCube high-energy neutrino detector, including periods of joint operation between 2007-2010. These include parts of the 2005-2007 run and the 2009-2010 run for LIGO-Virgo, and IceCube's observation periods with 22, 59 and 79 strings. We find no significant coincident events, and use the search results to derive upper limits on the rate of joint sources for a range of source emission parameters. For the optimistic assumption of gravitational-wave emission energy of 10-2M c2 at ∼150Hz with ∼60ms duration, and high-energy neutrino emission of 1051erg comparable to the isotropic gamma-ray energy of gamma-ray bursts, we limit the source rate below 1.6×10-2Mpc-3yr-1. We also examine how combining information from gravitational waves and neutrinos will aid discovery in the advanced gravitational-wave detector era
A gravitational wave observatory operating beyond the quantum shot-noise limit
No full textAround the globe several observatories are seeking the first direct detection of gravitational waves (GWs). These waves are predicted by Einstein’s general theory of relativity and are generated, for example, by black-hole binary systems. Present GW detectors are Michelson-type kilometre-scale laser interferometers measuring the distance changes between mirrors suspended in vacuum. The sensitivity of these detectors at frequencies above several hundred hertz is limited by the vacuum (zero-point) fluctuations of the electromagnetic field. A quantum technology—the injection of squeezed light—offers a solution to this problem. Here we demonstrate the squeezed-light enhancement of GEO600, which will be the GWobservatory operated by the LIGO Scientific Collaboration in its search for GWs for the next 3–4 years. GEO600 now operates with its best ever sensitivity, which proves the usefulness of quantum entanglement and the qualification of squeezed light as a key technology for future GW astronomy.J. Abadie... M.R. Ganija... D.J. Hosken... J. Munch... D.J. Ottaway... P.J. Veitch... et al. J. Abadie... M. R. Ganija...D. J. Hosken... J. Munch... D. J. Ottaway... P. J. Veitch... et al., (LIGO Scientific Collaboration
First searches for optical counterparts to gravitational-wave candidate events
No full textDuring the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers showed strong evidence for being astrophysical in nature. We compare the sensitivities of these observations to several model light curves from possible sources of interest, and discuss prospects for future joint GW-optical observations of this type
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