Chasing Gravitational Waves with the Cherenkov Telescope Array

TL;DR

This paper explores how the Cherenkov Telescope Array can detect very-high-energy photons from neutron star mergers identified by gravitational wave observatories, enhancing multimessenger astronomy.

Contribution

It evaluates the potential of CTA to observe VHE emissions from gravitational wave events and discusses optimized follow-up strategies.

Findings

Estimated number of detectable GW events with CTA

Development of rapid follow-up observation modes

Assessment of on- and off-axis emission detectability

Abstract

The detection of gravitational waves from a binary neutron star merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this gravitational wave event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a gravitational wave signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. New observing modes and follow-up strategies are being developed for CTA to rapidly cover localization areas of gravitational wave events that are typically larger than the CTA field of view. This work will evaluate and provide estimations on the expected number of of gravitational wave events that will be observable with CTA, considering both on- and off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA.