A Joint Fermi-GBM and Swift-BAT Analysis of Gravitational-Wave Candidates from the Third Gravitational-wave Observing Run

TL;DR

This study conducts joint searches using Fermi-GBM and Swift-BAT for gamma-ray and X-ray counterparts to gravitational-wave events from the third LIGO-Virgo observing run, setting upper limits on gamma-ray emission.

Contribution

It introduces a combined analysis approach of Fermi-GBM and Swift-BAT data to search for electromagnetic counterparts to GW events, providing new constraints on gamma-ray emissions.

Findings

No gamma-ray or X-ray counterparts detected.

Established upper limits on gamma-ray luminosity for GW events.

Constrained theoretical models of gamma-ray emission from black hole mergers.

Abstract

We present Fermi Gamma-ray Burst Monitor (Fermi-GBM) and Swift Burst Alert Telescope (Swift-BAT) searches for gamma-ray/X-ray counterparts to gravitational wave (GW) candidate events identified during the third observing run of the Advanced LIGO and Advanced Virgo detectors. Using Fermi-GBM on-board triggers and sub-threshold gamma-ray burst (GRB) candidates found in the Fermi-GBM ground analyses, the Targeted Search and the Untargeted Search, we investigate whether there are any coincident GRBs associated with the GWs. We also search the Swift-BAT rate data around the GW times to determine whether a GRB counterpart is present. No counterparts are found. Using both the Fermi-GBM Targeted Search and the Swift-BAT search, we calculate flux upper limits and present joint upper limits on the gamma-ray luminosity of each GW. Given these limits, we constrain theoretical models for the emission of gamma-rays from binary black hole mergers.