First Searches for Optical Counterparts to Gravitational-Wave Candidate Events

Abstract

During 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.

Localization and Broadband Follow-Up of the Gravitational-Wave Transient Gw150914

“…The first campaign to find EM counterparts triggered by lowlatency GW event candidates was carried out with the initial (Abadie et al 2012a(Abadie et al , 2012bEvans et al 2012;Aasi et al 2014). In preparing for Advanced detector operations, the LIGO and Virgo collaborations worked with the broader astronomy community to set up an evolved and greatly expanded EM follow-up program.…”

iPTF SEARCH FOR AN OPTICAL COUNTERPART TO GRAVITATIONAL-WAVE TRANSIENT GW150914

“…Nevertheless, the prospect of finding EM counterparts by searching large sky areas is promising as the search methodology is steadily improving-from early efforts in the enhanced LIGO S6 run (Aasi et al 2014), to proof-of-concept localizations of coarse Fermi gamma-ray bursts (Singer et al 2013, to a score of EM facilities promptly responding to GW150914 (Abbott et al 2016a).…”

Prospects and challenges in the electromagnetic follow-up of LIGO-Virgo gravitational wave transients

“…[30][31][32][33] MBTA is a matched filter algorithm 39 which uses a bank of templates (created before the analysis, and updated regularly) to search for potential CBC events in each interferometer's data. The search is done by filtering the data in the frequency domain, and using two frequency bands to reduce the sampling rate needed for the low-frequency part of the templates.…”

“…The EM follow-up program of Initial LIGO and Virgo and its results have been fully discussed elsewhere. [30][31][32][33] The LIGO-Virgo Collaborations expect to hold a similar program in the advanced detector era and have recently released a memorandum of understanding (MOU) call for the joint GW-EM follow-up program. The MOU call was very well received, and several tens of EM facilities, covering the whole EM spectrum, have expressed their interest.…”