The advanced gravitational wave interferometers are reaching unprecedented levels of strain sensitivity, that is, of accessible volume of Universe, in search for the most elusive cosmic sources. In this effort, the optical design of these detectors places increasingly stringent requirements on the components. Thermal effects, related to the fraction of laser beam power absorbed in the optics, and deviation of components from specifications, intrinsic to the state of art of the production processes, need to be addressed to recover the ideal operation of the detector. Ring heaters (RHs) are thermally coupled actuators conceived to precisely tune the radius of curvature (RoC) of the highly reflective surface of mirrors. The actuator concept has been improved and properly rescaled to design dedicated heaters for different mirrors of the Advanced Virgo detector (namely test masses, power and signal recycling mirrors, filter cavity mirrors). This paper describes the design features and performances of the RHs installed around the test masses of Advanced Virgo, highlighting the improvements of this design with respect to previous actuators. In this case, the dynamic actuation range reaches 100 m over a static RoC value of 1500 m, with the deformation largely dominated by the spherical component. The obtained actuation gain is dRoCdP = − 0.93 m W−1, with a typical settling time of about 6 h.

Equation (7) of the original paper (Aasi et al. 2015) is in error; it should read

The discovery of the gravitational-wave (GW) source GW150914 with the Advanced LIGO detectors provides the first observational evidence for the existence of binary black hole (BH) systems that inspiral and merge within the age of the universe. Such BH mergers have been predicted in two main types of formation models, involving isolated binaries in galactic fields or dynamical interactions in young and old dense stellar environments. The measured masses robustly demonstrate that relatively “heavy” BHs ( 25  M) can form in nature. This discovery implies relatively weak massive-star winds and thus the formation of GW150914 in an environment with a metallicity lower than about 1/2 of the solar value. The rate of binary-BH (BBH) mergers inferred from the observation of GW150914 is consistent with the higher end of rate predictions ( 1  Gpc yr) from both types of formation models. The low measured redshift (z 0.1  ) of GW150914 and the low inferred metallicity of the stellar progenitor imply either BBH formation in a low-mass galaxy in the local universe and a prompt merger, or formation at high redshift with a time delay between formation and merger of several Gyr. This discovery motivates further studies of binary-BH formation astrophysics. It also has implications for future detections and studies by Advanced LIGO and Advanced Virgo, and GW detectors in space.

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

The first observing run of Advanced LIGO spanned 4 months, from September 12, 2015 to January 19, 2016, during which gravitational waves were directly detected from two binary black hole systems, namely GW150914 and GW151226. Confident detection of gravitational waves requires an understanding of instrumental transients and artifacts that can reduce the sensitivity of a search. Studies of the quality of the detector data yield insights into the cause of instrumental artifacts and data quality vetoes specific to a search are produced to mitigate the effects of problematic data. In this paper, the systematic removal of noisy data from analysis time is shown to improve the sensitivity of searches for compact binary coalescences. The output of the PyCBC pipeline, which is a python-based code package used to search for gravitational wave signals from compact binary coalescences, is used as a metric for improvement. GW150914 was a loud enough signal that removing noisy data did not improve its significance. However, the removal of data with excess noise decreased the false alarm rate of GW151226 by more than two orders of magnitude, from 1 in 770 years to less than 1 in 186000 years.

We present the results of the first search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line configuration during the period January September 2007, which coincided with the fifth and first science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No significant coincident events were observed. We place limits on the density of joint high energy neutrino gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events. Subject headings: gravitational waves — high energy neutrinos 1 Institut d’Investigació per a la Gestió Integrada de les Zones Costaneres (IGIC) Universitat Politècnica de València. C/ Paranimf 1 , 46730 Gandia, Spain. 2 CPPM, Aix-Marseille Université, CNRS/IN2P3, Marseille, France 3 GRPHE Institut universitaire de technologie de Colmar, 34 rue du Grillenbreit BP 50568 68008 Colmar, France 4 Technical University of Catalonia, Laboratory of Applied Bioacoustics, Rambla Exposició, 08800 Vilanova i la Geltrú, Barcelona, Spain 5 INFN Sezione di Genova, Via Dodecaneso 33, 16146 Genova, Italy 6 Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen Centre for Astroparticle Physics, Erwin-Rommel-Str. 1, 91058 Erlangen, Germany 7 Direction des Sciences de la Matière Institut de recherche sur les lois fondamentales de l’Univers Service d’Electronique des Détecteurs et d’Informatique, CEA Saclay, 91191 Gif-surYvette Cedex, France 8 Nikhef, Science Park, Amsterdam, The Netherlands 9 APC, Université Paris Diderot, CNRS/IN2P3, CEA/IRFU, Observatoire de Paris, Sorbonne Paris Cité, 75205 Paris, France 10 LAM Laboratoire d’Astrophysique de Marseille, Pôle de l’Étoile Site de Château-Gombert, rue Frédéric Joliot-Curie 38, 13388 Marseille Cedex 13, France 11 INFN Sezione di Bologna, Viale C. Berti-Pichat 6/2, 40127 Bologna, Italy 12 Dipartimento di Fisica dell’Università, Viale Berti Pichat 6/2, 40127 Bologna, Italy 13 IFIC Instituto de F́ısica Corpuscular, Edificios Investigación de Paterna, CSIC Universitat de València, Apdo. de Correos 22085, 46071 Valencia, Spain 14 INFN -Sezione di Roma, P.le Aldo Moro 2, 00185 Roma, Italy 15 Dipartimento di Fisica dell’Università La Sapienza, P.le Aldo Moro 2, 00185 Roma, Italy 16 Clermont Université, Université Blaise Pascal, CNRS/IN2P3, Laboratoire de Physique Corpusculaire, BP 10448, 63000 Clermont-Ferrand, France 17 Géoazur Université de Nice Sophia-Antipolis, CNRS/INSU, IRD, Observatoire de la Côte d’Azur and Université Pierre et Marie Curie, BP 48, 06235 Villefranche-surmer, France 18 INFN Sezione di Bari, Via E. Orabona 4, 70126 Bari, Italy 19 INFN Laboratori Nazionali del Sud (LNS), Via S. Sofia 62, 95123 Catania, Italy 20 MIO, Mediterranean Institute of Oceanography, AixMarseille University, 13288, Marseille, Cedex 9, France; Université du Sud Toulon-Var, 83957, La Garde Cedex, France CNRS-INSU/IRD UM 110 21 Univ Paris-Sud , 91405 Orsay Cedex, France 22 Kernfysisch Versneller Instituut (KVI), University of Groningen, Zernikelaan 25, 9747 AA Groningen, The Netherlands 23 Direction des Sciences de la Matière Institut de recherche sur les lois fondamentales de l’Univers Service de Physique des Particules, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France 24 INFN Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa, Italy 25 Dipartimento di Fisica dell’Università di Pisa, Largo B. Pontecorvo 3, 56127 Pisa, Italy 26 University Mohammed I, Laboratory of Physics of Matter and Radiations, B.P.717, Oujda 6000, Morocco 27 Royal Netherlands Institute for Sea Research (NIOZ), Landsdiep 4,1797 SZ ’t Horntje (Texel), The Netherlands 28 Dr. Remeis-Sternwarte and ECAP, Universität ErlangenNürnberg, Sternwartstr. 7, 96049 Bamberg, Germany 29 Universiteit Utrecht, Faculteit Betawetenschappen, Princetonplein 5, 3584 CC Utrecht, The Netherlands 30 Universiteit van Amsterdam, Instituut voor Hoge-Energie Fysica, Science Park 105, 1098 XG Amsterdam, The Netherlands 31 Moscow State University, Skobeltsyn Institute of Nuclear Physics, Leninskie gory, 119991 Moscow, Russia 32 INFN Sezione di Catania, Viale Andrea Doria 6, 95125 Catania, Italy 33 Dipartimento di Fisica ed Astronomia dell’Università, Viale Andrea Doria 6, 95125 Catania, Italy 34 Département de Physique Nucléaire et Corpusculaire, Université de Genève, 1211, Geneva, Switzerland 35 Institute for Space Sciences, R-77125 Bucharest, Măgurele, Romania 36 IPHC-Institut Pluridisciplinaire Hubert Curien Université de Strasbourg et CNRS/IN2P3 23 rue du Loess, BP 28, 67037 Strasbourg Cedex 2, France 37 ITEP Institute for Theoretical and Experimental Physics, B. Cheremushkinskaya 25, 117218 Moscow, Russia 38 Dipartimento di Fisica dell’Università, Via Dodecaneso 33, 16146 Genova, Italy 39 Also at University of Leiden, the Netherlands 40 On leave of absence at the Humboldt-Universität zu Berlin 41 Also at Accademia Navale di Livorno, Livorno, Italy 42 LIGO California Institute of Technology, Pasadena, CA 91125, USA 43 California State University Fullerton, Fullerton CA 92831 USA 44 SUPA, University of Glasgow, Glasgow, G12 8QQ, United Kingdom 45 Laboratoire d’Annecy-le-Vieux de Physique des Particules 4 The ANTARES Collaboration, the LIGO Scientific Collaboration and the Virgo Collaboration (LAPP), Université de Savoie, CNRS/IN2P3, F-74941 AnnecyLe-Vieux, France 46 INFN, Sezione di Napoli, Complesso Universitario di Monte S.Angelo, I-80126 Napoli, Italy 47 Università di Napoli ’Federico II’, Complesso Universitario di Monte S.Angelo, I-80126 Napoli, Italy 48 Università di Salerno, I-84084 Fisciano (Salerno), Italy 49 LIGO Livingston Observatory, Livingston, LA 70754, USA 50 Cardiff University, Cardiff, CF24 3AA, United Kingdom 51 University of Sannio at Benevento, I-82100 Benevento, Italy and INFN (Sezione di Napoli), Italy 52 Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik, D-30167 Hannover, Germany 53 Leibniz Universität Hannover, D-30167 Hannover, Germany 54 VU University Amsterdam, De Boelelaan 1081, 1081 HV Amsterdam, the Netherlands 55 National Astronomical Observatory of Japan, Tokyo 181-8588, Japan 56 University of Wisconsin–Milwaukee, Milwaukee, WI 53201, USA 57 Università di Siena, I-53100 Siena, Italy 58 University of Florida, Gainesville, FL 32611, USA 59 LIGO Hanford Observatory, Richland, WA 99352, USA 60 University of Birmingham, Birmingham, B15 2TT, United Kingdom 61 Albert-Einstein-Institut, Max-Planck-Institut für Gravitationsphysik, D-14476 Golm, Germany 62 Montana State University, Bozeman, MT 59717, USA 63 European Gravitational Observatory (EGO), I-56021 Cascina (PI), Italy 64 Syracuse University, Syracuse, NY 13244, USA 65 LIGO Massachusetts Institute of Technology, Cambridge, MA 02139, USA 66 Columbia University, New York, NY 10027, USA 67 Stanford University, Stanford, CA 94305, USA 68 IM-PAN 00-956 Warsaw, Poland 69 Astronomical Observatory Warsaw University 00-478 Warsaw, Poland 70 CAMK-PAN 00-716 Warsaw, Poland 71 Bia lystok University 15-424 Bia lystok, Poland 72 NCBJ 05-400 Świerk-Otwock, Poland 73 Institute of Astronomy 65-265 Zielona Góra, Poland 74 The University of Texas at Brownsville, Brownsville, TX 78520, USA 75 San Jose State University, San Jose, CA 95192, USA 76 Moscow State University, Moscow, 119992, Russia 77 LAL, Université Paris-Sud, IN2P3/CNRS, F-91898 Orsay, France 78 ESPCI, CNRS, F-75005 Paris, France 79 NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA 80 University of Western Australia, Crawley, WA 6009, Australia 81 The Pennsylvania State University, University Park, PA 16802, USA 82 Université Nice-Sophia-Antipolis, CNRS, Observatoire de la Côte d’Azur, F-06304 Nice, France 83 Institut de Physique de Rennes, CNRS, Université de Rennes 1, 35042 Rennes, France 84 Laboratoire des Matériaux Avancés (LMA), IN2P3/CNRS, F-69622 Villeurbanne, Lyon, France 85 Washington State University, Pullman, WA 99164, USA 86 INFN, Sezione di Perugia, I-06123 Perugia, Italy 87 Università di Perugia, I-06123 Perugia, Italy 88 INFN, Sezione di Firenze, I-50019 Sesto Fiorentino, Italy 89 Università degli Studi di Urbino ’Carlo Bo’, I-61029 Urbino, Italy 90 University of Oregon, Eugene, OR 97403, USA 91 Laboratoire Kastler Brossel, ENS, CNRS, UPMC, Université Pierre et Marie Curie, 4 Place Jussieu, F-75005 Paris, France 92 University of Maryland, College Park, MD 20742 USA 93 Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain 94 University of Massachusetts Amherst, Amherst, MA 01003, USA 95 Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, Ontario, M5S 3H8, Canada 96 Tsinghua University, Beijing 100084 China 97 University of Michigan, Ann Arbor, MI 48109, USA 98 Louisiana State University, Baton Rouge, LA 70803, USA 99 The University of Mississippi, University, MS 38677, USA 100 Charles Sturt University, Wagga Wagga, NSW 2678, Australia 101 Caltech-CaRT, Pasadena, CA 91125, USA 102 Pusan National University, Busan 609-735, Korea 103 Australian National University, Canberra, ACT 0200, Australia 104 Carleton College, Northfield, MN 55057, USA 105 The University of Melbourne, Parkville, VIC 3010, Australia 106 INFN, Sezione di Roma Tor Vergata, I-00133 Roma, Italy 107 Università di Roma Tor Vergata, I-00133 Roma, Italy 108 Università dell’Aquila, I-67100 L’Aquila, Italy 109 Instituto Nacional de Pesquisas Espaciais, 12227-010 São José dos Campos, SP, Brazil 110 The University of Sheffield, Sheffield S10 2TN, United Kingdom 111 Wigner RCP, RMKI, H-1121 Budapest, Konkoly Thege Miklós út 29-33, Hungary 112 Inter-University Centre for Astronomy and Astrophysics, Pune 411007, India 113 University of Minnesota, M

We describe a directed search for continuous gravitational waves in data from the sixth LIGO science run. The target was the nearby globular cluster NGC 6544 at a distance of 2.7 kpc. The search covered a broad band of frequencies along with first and second frequency derivatives for a fixed sky position. The search coherently integrated data from the two LIGO interferometers over a time span of 9.2 days using the matched-filtering F-statistic. We found no gravitational-wave signals and set 95% confidence upper limits as stringent as 6.0 X 10^{-25} on intrinsic strain and 8.5 X 10^{-6} on fiducial ellipticity. These values beat the indirect limits from energy conservation for stars with characteristic spindown ages older than 300 years and are within the range of theoretical predictions for possible neutron-star ellipticities. An important feature of this search was use of a barycentric resampling algorithm which substantially reduced computational cost; this method will be used extensively in searches of Advanced LIGO and Virgo detector data.

We present the result of searches for gravitational waves from 200 pulsars using data from the first observing run of the Advanced LIGO detectors. We find no significant evidence for a gravitational-wave signal from any of these pulsars, but we are able to set the most constraining upper limits yet on their gravitational-wave amplitudes and ellipticities. For eight of these pulsars, our upper limits give bounds that are improvements over the indirect spin-down limit values. For another 32, we are within a factor of 10 of the spin-down limit, and it is likely that some of these will be reachable in future runs of the advanced detector. Taken as a whole, these new results improve on previous limits by more than a factor of two.

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Erratum: “First Search for Gravitational Waves from Known Pulsars with Advanced LIGO” (2017, ApJ, 839, 12) B. Abbott, R. Abbott, T. Abbott, R. Abernathy, F. Acernese, K. Ackley, C. Adams, T. Adams, P. Addesso, R. Adhikari, et al.

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 find 2 and 4 neutrino candidates detected by IceCube, and 1 and 0 detected by ANTARES, within $\pm500$ s around the respective gravitational wave signals, consistent with the expected background rate. None of these neutrino candidates are found to be directionally coincident with GW151226 or LVT151012. We use non-detection to constrain isotropic-equivalent high-energy neutrino emission from GW151226 adopting the GW event's 3D localization, to less than $2\times 10^{51}-2\times10^{54}$ erg.

We present the results of the search for gravitational waves (GWs) associated with $\gamma$-ray bursts detected during the first observing run of the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO). We find no evidence of a GW signal for any of the 41 $\gamma$-ray bursts for which LIGO data are available with sufficient duration. For all $\gamma$-ray bursts, we place lower bounds on the distance to the source using the optimistic assumption that GWs with an energy of $10^{-2}M_\odot c^2$ were emitted within the $16$-$500\,$Hz band, and we find a median 90% confidence limit of 71$\,$Mpc at 150$\,$Hz. For the subset of 19 short/hard $\gamma$-ray bursts, we place lower bounds on distance with a median 90% confidence limit of 90$\,$Mpc for binary neutron star (BNS) coalescences, and 150 and 139$\,$Mpc for neutron star-black hole coalescences with spins aligned to the orbital angular momentum and in a generic configuration, respectively. These are the highest distance limits ever achieved by GW searches. We also discuss in detail the results of the search for GWs associated with GRB 150906B, an event that was localized by the InterPlanetary Network near the local galaxy NGC 3313, which is at a luminosity distance of 54$\,$Mpc ($z=0.0124$). Assuming the $\gamma$-ray emission is beamed with a jet half-opening angle $\leq 30^{\circ}$, we exclude a BNS and a neutron star-black hole in NGC 3313 as the progenitor of this event with confidence $>99$%. Further, we exclude such progenitors up to a distance of 102$\,$Mpc and 170$\,$Mpc, respectively.

The gravitational-wave signal GW150914 was first identified on Sept 14 2015 by searches for short-duration gravitational-wave transients. These searches identify time-correlated transients in multiple detectors with minimal assumptions aboutthe signal morphology, allowing them to be sensitive to gravitational waves emitted by a wide range of sources including binary black-hole mergers. Over the observational period from September 12th to October 20th 2015, these transient searches were sensitive to binary black-hole mergers similar to GW150914 to an average distance of $\sim 600$ Mpc. In this paper, we describe the analyses that first detected GW150914 as well as the parameter estimation and waveform reconstruction techniques that initially identified GW150914 as the merger of two black holes. We find that the reconstructed waveform is consistent with the signal from a binary black-hole merger with a chirp mass of $\sim 30 \, M_\odot$ and a total mass before merger of $\sim 70 \, M_\odot$ in the detector frame.

The LIGO detection of GW150914 provides an unprecedented opportunity to study the two-body motion of a compact-object binary in the large-velocity, highly nonlinear regime, and to witness the final merger of the binary and the excitation of uniquely relativistic modes of the gravitational field. We carry out several investigations to determine whether GW150914 is consistent with a binary black-hole merger in general relativity. We find that the final remnant's mass and spin, as determined from the low-frequency (inspiral) and high-frequency (postinspiral) phases of the signal, are mutually consistent with the binary black-hole solution in general relativity. Furthermore, the data following the peak of GW150914 are consistent with the least-damped quasinormal mode inferred from the mass and spin of the remnant black hole. By using waveform models that allow for parametrized general-relativity violations during the inspiral and merger phases, we perform quantitative tests on the gravitational-wave phase in the dynamical regime and we determine the first empirical bounds on several high-order post-Newtonian coefficients. We constrain the graviton Compton wavelength, assuming that gravitons are dispersed in vacuum in the same way as particles with mass, obtaining a 90%-confidence lower bound of 10^{13}  km. In conclusion, within our statistical uncertainties, we find no evidence for violations of general relativity in the genuinely strong-field regime of gravity.

We present an archival search for transient gravitational-wave bursts in coincidence with 27 single pulse triggers from Green Bank Telescope pulsar surveys, using the LIGO, Virgo and GEO interferometer network. We also discuss a check for gravitational-wave signals in coincidence with Parkes Fast Radio Bursts using similar methods. Data analyzed in these searches were collected between 2007 and 2013. Possible sources of emission of both short-duration radio signals and transient gravitational-wave emission include starquakes on neutron stars, binary coalescence of neutron stars, and cosmic string cusps. While no evidence for gravitational-wave emission in coincidence with these radio transients was found, the current analysis serves as a prototype for similar future searches using more sensitive second-generation interferometers.

We compare GW150914 directly to simulations of coalescing binary black holes in full general relativity, accounting for all the spin-weighted quadrupolar modes, and separately accounting for all the quadrupolar and octopolar modes. Consistent with the posterior distributions reported in LVC_PE[1] (at 90% confidence), we find the data are compatible with a wide range of nonprecessing and precessing simulations. Followup simulations performed using previously-estimated binary parameters most resemble the data. Comparisons including only the quadrupolar modes constrain the total redshifted mass Mz \in [64 - 82M_\odot], mass ratio q = m2/m1 \in [0.6,1], and effective aligned spin \chi_eff \in [-0.3, 0.2], where \chi_{eff} = (S1/m1 + S2/m2) \cdot\hat{L} /M. Including both quadrupolar and octopolar modes, we find the mass ratio is even more tightly constrained. Simulations with extreme mass ratios and effective spins are highly inconsistent with the data, at any mass. Several nonprecessing and precessing simulations with similar mass ratio and \chi_{eff} are consistent with the data. Though correlated, the components' spins (both in magnitude and directions) are not significantly constrained by the data. For nonprecessing binaries, interpolating between simulations, we reconstruct a posterior distribution consistent with previous results. The final black hole's redshifted mass is consistent with Mf,z between 64.0 - 73.5M_\odot and the final black hole's dimensionless spin parameter is consistent with af = 0.62 - 0.73. As our approach invokes no intermediate approximations to general relativity and can strongly reject binaries whose radiation is inconsistent with the data, our analysis provides a valuable complement to LVC_PE[1].

On September 14, 2015 at 09:50:45 UTC the two detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) simultaneously observed the binary black hole merger GW150914. We report the results of a matched-filter search using relativistic models of compact-object binaries that recovered GW150914 as the most significant event during the coincident observations between the two LIGO detectors from September 12 to October 20, 2015. GW150914 was observed with a matched filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203 000 years, equivalent to a significance greater than 5.1 σ.

We report results of a deep all-sky search for periodic gravitational waves from isolated neutron stars in data from the S6 LIGO science run. The search was possible thanks to the computing power provided by the volunteers of the Einstein@Home distributed computing project. We find no significant signal candidate and set the most stringent upper limits to date on the amplitude of gravitational wave signals from the target population. At the frequency of best strain sensitivity, between $170.5$ and $171$ Hz we set a 90% confidence upper limit of ${5.5}^{-25}$, while at the high end of our frequency range, around 505 Hz, we achieve upper limits $\simeq {10}^{-24}$. At $230$ Hz we can exclude sources with ellipticities greater than $10^{-6}$ within 100 pc of Earth with fiducial value of the principal moment of inertia of $10^{38} \textrm{kg m}^2$. If we assume a higher (lower) gravitational wave spindown we constrain farther (closer) objects to higher (lower) ellipticities.

Following a major upgrade, the two advanced detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) held their first observation run between September 2015 and January 2016. With a strain sensitivity of 10^{-23}/sqrt[Hz] at 100 Hz, the product of observable volume and measurement time exceeded that of all previous runs within the first 16 days of coincident observation. On September 14, 2015, the Advanced LIGO detectors observed a transient gravitational-wave signal determined to be the coalescence of two black holes [B. P. Abbott et al., Phys. Rev. Lett. 116, 061102 (2016)], launching the era of gravitational-wave astronomy. The event, GW150914, was observed with a combined signal-to-noise ratio of 24 in coincidence by the two detectors. Here, we present the main features of the detectors that enabled this observation. At full sensitivity, the Advanced LIGO detectors are designed to deliver another factor of 3 improvement in the signal-to-noise ratio for binary black hole systems similar in mass to GW150914.

ABSTRACT This article provides supplemental information for a Letter reporting the rate of (BBH) coalescences inferred from 16 days of coincident Advanced LIGO observations surrounding the transient (GW) signal GW150914. In that work we reported various rate estimates whose 90% confidence intervals fell in the range 2–600 Gpc−3 yr−1. Here we give details on our method and computations, including information about our search pipelines, a derivation of our likelihood function for the analysis, a description of the astrophysical search trigger distribution expected from merging BBHs, details on our computational methods, a description of the effects and our model for calibration uncertainty, and an analytic method for estimating our detector sensitivity, which is calibrated to our measurements.