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Title: Searching for high-energy gamma-ray counterparts to gravitational-wave sources with Fermi-LAT: A needle in a haystack

At least a fraction of gravitational-wave (GW) progenitors are expected to emit an electromagnetic (EM) signal in the form of a short gamma-ray burst (sGRB). Discovering such a transient EM counterpart is challenging because the LIGO/VIRGO localization region is much larger (several hundreds of square degrees) than the field of view of X-ray, optical, and radio telescopes. The Fermi Large Area Telescope (LAT) has a wide field of view (~2.4 sr) and detects ~2–3 sGRBs per year above 100 MeV. It can detect them not only during the short prompt phase, but also during their long-lasting high-energy afterglow phase. If other wide-field, high-energy instruments such as Fermi-GBM, Swift-BAT, or INTEGRAL-ISGRI cannot detect or localize with enough precision an EM counterpart during the prompt phase, the LAT can potentially pinpoint it with $$\lesssim 10$$ arcmin accuracy during the afterglow phase. This routinely happens with gamma-ray bursts. Moreover, the LAT will cover the entire localization region within hours of any triggers during normal operations, allowing the γ-ray flux of any EM counterpart to be measured or constrained. As a result, we illustrate two new ad hoc methods to search for EM counterparts with the LAT and their application to the GW candidate LVT151012.
ORCiD logo [1] ; ORCiD logo [1] ;  [1] ;  [1]
  1. SLAC National Accelerator Lab., Stanford Univ., Stanford, CA (United States)
Publication Date:
Grant/Contract Number:
Accepted Manuscript
Journal Name:
The Astrophysical Journal. Letters
Additional Journal Information:
Journal Volume: 841; Journal Issue: 1; Journal ID: ISSN 2041-8213
Institute of Physics (IOP)
Research Org:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org:
Country of Publication:
United States
79 ASTRONOMY AND ASTROPHYSICS; gamma rays: general; gravitational waves; methods: observational
OSTI Identifier: