Search for Gravitational Waves Associated with Gamma-Ray Bursts Detected by Fermi and Swift During the LIGO-Virgo Run O3a

TL;DR

This study searched for gravitational waves associated with gamma-ray bursts detected by Fermi and Swift during LIGO-Virgo's O3a run, finding no significant signals but setting distance bounds for various source types.

Contribution

Introduces a method to estimate the astrophysical probability of binary merger triggers and applies it to gamma-ray burst follow-ups during LIGO-Virgo's O3a run.

Findings

No significant gravitational-wave signals detected

Established lower bounds on source distances

Applied a novel probability calculation method

Abstract

We search for gravitational-wave transients associated with gamma-ray bursts detected by the Fermi and Swift satellites during the first part of the third observing run of Advanced LIGO and Advanced Virgo (1 April 2019 15:00 UTC - 1 October 2019 15:00 UTC). 105 gamma-ray bursts were analyzed using a search for generic gravitational-wave transients; 32 gamma-ray bursts were analyzed with a search that specifically targets neutron star binary mergers as short gamma-ray burst progenitors. We describe a method to calculate the probability that triggers from the binary merger targeted search are astrophysical and apply that method to the most significant gamma-ray bursts in that search. We find no significant evidence for gravitational-wave signals associated with the gamma-ray bursts that we followed up, nor for a population of unidentified subthreshold signals. We consider several source types and signal morphologies, and report for these lower bounds on the distance to each gamma-ray burst.