Using negative-latency gravitational wave alerts to detect prompt radio bursts from binary neutron star mergers with the Murchison Widefield Array

TL;DR

This paper explores how negative-latency gravitational wave alerts can enable rapid low-frequency radio observations with the Murchison Widefield Array to detect prompt radio bursts from binary neutron star mergers, potentially capturing signals missed by traditional methods.

Contribution

It introduces a new observational mode for the MWA triggered by negative-latency alerts, improving the chances of detecting prompt radio signals from neutron star mergers.

Findings

Negative-latency alerts can reduce response time up to 300 MHz observations.

The proposed mode can detect FRB-like bursts from events similar to GW170817.

Current methods are insufficient for high-frequency triggered observations within the BNS horizon.

Abstract

We examine how fast radio burst (FRB)-like signals predicted to be generated during the merger of a binary neutron star (BNS) may be detected in low-frequency radio observations triggered by the aLIGO/Virgo gravitational wave detectors. The rapidity, directional accuracy, and sensitivity of follow-up observations with the Murchison Widefield Array (MWA) are considered. We show that with current methodology, the rapidity criteria fails for triggered MWA observations above 136 MHz for BNS mergers within the aLIGO/Virgo horizon, for which little dispersive delay is expected. A calculation of the expected reduction in response time by triggering on `negative latency' alerts from aLIGO/Virgo observations of gravitational waves generated by the BNS inspiral is presented. This allows for observations up to 300 MHz where the radio signal is expected to be stronger. To compensate for the poor positional accuracy expected from these alerts, we propose a new MWA observational mode that is capable of viewing one quarter of the sky. We show the sensitivity of this mode is sufficient to detect an FRB-like burst from an event similar to GW170817 if it occurred during the ongoing aLIGO/Virgo third science run (O3).