Science with an ngVLA: Radio Emission from Short Gamma-ray Bursts in the Multi-Messenger Era

TL;DR

This paper models radio emissions from short gamma-ray bursts to predict detectability with future radio telescopes, especially in conjunction with gravitational wave signals from neutron star mergers.

Contribution

It provides estimates of radio detectability of short GRBs and their components in the era of multi-messenger astronomy, guiding future observational strategies.

Findings

Up to 20% of off-axis jet radio components may be detectable coincident with GW signals.

Approximately 10% of events with radio emission from tidal ejecta are detectable.

Next Generation Very Large Array will significantly enhance detection prospects.

Abstract

We investigate the expected radio emission from short GRBs, guided by the observed distributions of their afterglow parameters. Our motivation is to explore the radio signatures of the forward and reverse shock in a sGRB jet, as well as the off-axis jet component and radio emission from the dynamical ejecta. We estimate the fraction of GRBs detectable in the radio that may be coincident with a GW signal from a neutron star (NS) merger. At the distance to which aLIGO at design specification is sensitive to GWs from NS mergers, we may detect up to 20 % of off-axis jet radio components of these events, and up to about 10 % of events with radio emission from the tidal ejecta shocking with the external medium. We discuss our results in light of the Next Generation Very Large Array, expected to make significant progress in detecting radio signals from sGRBs.