FRB131104 Swift BAT data revisited: No evidence of a gamma-ray counterpart

TL;DR

A re-analysis of Swift BAT data around FRB 131104 finds no significant gamma-ray emission, setting upper limits and challenging previous claims of a high-energy counterpart, supporting the idea that most FRBs are not linked to catastrophic gamma-ray events.

Contribution

This study provides the first comprehensive re-analysis of BAT data for FRB 131104, establishing upper limits that refute earlier claims of a gamma-ray counterpart.

Findings

No significant gamma-ray emission detected

Set upper limits on fluence in 15-150 keV range

Supports non-association of FRB with gamma-ray bursts

Abstract

We present a re-analysis of the Swift Burst Alert Telescope (BAT) data around the radio detection of FRB 131104. Possible evidence of a gamma-ray counterpart was presented by DeLaunay et al. However, based on our analysis using all the available BAT data, no significant emission is found in either the temporal or the image domain. We place a 5~sigma fluence upper limit of 3.3 $\times$ 10$^{-6}$ erg cm$^{-2}$ and 2.7 $\times$ 10$^{-6}$ erg cm$^{-2}$ (15-150 keV) with an integration time of 300 s assuming a simple power-law spectrum with photon index of -1.2 and -2.0, respectively. Our result does not support the association of this FRB with a high-energy counterpart, in agreement with growing observational evidence that most FRBs are not associated to catastrophic events such as gamma-ray bursts.