Searching the Gamma-ray Sky for Counterparts to Gravitational Wave Sources: Fermi GBM and LAT Observations of LVT151012 and GW151226

TL;DR

This study used Fermi GBM and LAT data to search for electromagnetic counterparts to LIGO black hole mergers GW151226 and LVT151012, but found no detections, providing upper limits across large sky areas.

Contribution

It presents a comprehensive analysis of gamma-ray data for specific gravitational wave events, employing new techniques to characterize upper limits and coverage.

Findings

No electromagnetic counterparts detected by GBM or LAT.

Upper limits established across large sky regions.

Coverage limitations prevent constraining certain theoretical models.

Abstract

We present the Fermi Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) observations of the LIGO binary black hole merger event GW151226 and candi- date LVT151012. No candidate electromagnetic counterparts were detected by either the GBM or LAT. We present a detailed analysis of the GBM and LAT data over a range of timescales from seconds to years, using automated pipelines and new techniques for char- acterizing the upper limits across a large area of the sky. Due to the partial GBM and LAT coverage of the large LIGO localization regions at the trigger times for both events, dif- ferences in source distances and masses, as well as the uncertain degree to which emission from these sources could be beamed, these non-detections cannot be used to constrain the variety of theoretical models recently applied to explain the candidate GBM counterpart to GW150914.