Localization and Broadband Follow-up of the Gravitational-Wave Transient GW 150914

The LVC Collaboration,; Pierro, V.; Pinto, I. M.; Principe, M.; The Australian Square Kilometer Array Pathfinder (ASKAP) Collaboration,; The BOOTES Collaboration,; The Dark Energy Survey and the Dark Energy Camera GW-EM Collaborations,; The Fermi GBM Collaboration,; The GRAvitational Wave Inaf TeAm (GRAWITA),; The INTEGRAL Collaboration,; The Intermediate Palomar Transient Factory (iPTF) Collaboration,; The InterPlanetary Network,; The J-GEM Collaboration,; The La Silla–QUEST Survey,; The Liverpool Telescope Collaboration,; The Low Frequency Array (LOFAR) Collaboration,; The MASTER Collaboration,; The MAXI Collaboration,; The Murchison Wide-field Array (MWA) Collaboration,; The Pan-STARRS Collaboration,; The PESSTO Collaboration,; The Pi of the Sky Collaboration,; The SkyMapper Collaboration,; The Swift Collaboration,; Tarot, The; Zadko,; Algerian National Observatory,; and C2PU Collaboration,; The TOROS Collaboration,; and the VISTA Collaboration,

doi:10.3847/2041-8205/826/1/L13

A gravitational-wave (GW) transient was identified in data recorded by the Advanced Laser InterferometerGravitational-wave Observatory (LIGO) detectors on 2015 September 14. The event, initially designated G184098and later given the name GW150914, is described in detail elsewhere. By prior arrangement, preliminary estimatesof the time, significance, and sky location of the event were shared with 63 teams of observers covering radio,optical, near-infrared, X-ray, and gamma-ray wavelengths with ground- and space-based facilities. In this Letter wedescribe the low-latency analysis of the GW data and present the sky localization of the first observed compactbinary merger. We summarize the follow-up observations reported by 25 teams via private Gamma-rayCoordinates Network circulars, giving an overview of the participating facilities, the GW sky localizationcoverage, the timeline, and depth of the observations. As this event turned out to be a binary black hole merger,there is little expectation of a detectable electromagnetic (EM) signature. Nevertheless, this first broadbandcampaign to search for a counterpart of an Advanced LIGO source represents a milestone and highlights the broadcapabilities of the transient astronomy community and the observing strategies that have been developed to pursueneutron star binary merger events. Detailed investigations of the EM data and results of the EM follow-upcampaign are being disseminated in papers by the individual teams.