A Deep Targeted Search for Fast Radio Bursts from the Sites of Low-Redshift Short Gamma-Ray Bursts

TL;DR

This study conducted deep radio searches at multiple sites of low-redshift short gamma-ray bursts to detect potential associated fast radio bursts, but found no signals, constraining their possible energies.

Contribution

First comprehensive search for FRBs at SGRB sites using high-resolution data and machine learning, setting new limits on FRB energies from these sources.

Findings

No FRBs detected in 20 hours of observations.

Detected flux density thresholds of 87 mJy (Green Bank) and 21 mJy (Arecibo).

Constraints on FRB energies from SGRB sites to be below a few times 10^{38} erg.

Abstract

Some short gamma-ray bursts (SGRBs) are thought to be caused by the mergers of binary neutron stars which may sometimes produce massive neutron star remnants capable of producing extragalactic fast radio bursts (FRBs). We conducted a deep search for FRBs from the sites of six low-redshift SGRBs. We collected high time- and frequency-resolution data from each of the sites for 10 hours using the 2 GHz receiver of the Green Bank Telescope. Two of the SGRB sites we targeted were visible with the Arecibo Radio Telescope with which we conducted an additional 10 hours of 1.4 GHz observations for each. We searched our data for FRBs using the GPU-optimized dedispersion algorithm $\texttt{heimdall}$ and the machine-learning-based package $\texttt{FETCH}$ (Fast Extragalactic Transient Candidate Hunter). We did not discover any FRBs, but would have detected any with peak flux densities in excess of 87 mJy at the Green Bank Telescope or 21 mJy at Arecibo with a signal-to-noise ratio of at least 10. The isotropic-equivalent energy of any FRBs emitted from these sites in our bands during our observations must not have exceeded a few times $10^{38}$ erg, comparable to some of the lowest energy bursts yet seen from the first known repeating FRB 121102.