The gravitational-wave follow-up program of the Cherenkov Telescope Array

TL;DR

This paper discusses the Cherenkov Telescope Array's strategy for following up on gravitational-wave detections to identify very-high-energy photon counterparts, enhancing multi-messenger astronomy.

Contribution

It presents the CTA follow-up program, strategies, and prospects for detecting VHE emissions from gravitational-wave sources, advancing multi-messenger observational capabilities.

Findings

CTA will significantly improve VHE follow-up sensitivity.

Effective follow-up strategies are outlined for GW events.

Potential for VHE detection from GW counterparts is promising.

Abstract

The birth of gravitational-wave / electromagnetic astronomy was heralded by the joint observation of gravitational waves (GWs) from a binary neutron star (BNS) merger by Advanced LIGO and Advanced Virgo, GW170817, and of gamma-rays from the short gamma-ray burst GRB170817A by the Fermi Gamma-ray Burst Monitor (GBM) and INTEGRAL. This detection provided the first direct evidence that at least a fraction of BNSs are progenitors of short GRBs. GRBs are now also known to emit very-high-energy (VHE, > 100 GeV) photons as has been shown by recent independent detections of the GRBs 1901114C and 180720B by the ground-based gamma-ray detectors MAGIC and H.E.S.S. In the next years, the Cherenkov Telescope Array (CTA) will boost the searches for VHE counterparts thanks to its unprecedented sensitivity, rapid response and capability to monitor large sky areas via survey-mode operation. In this contribution, we present the CTA program of observations following the detection of GW events. We discuss various follow-up strategies and links to multi-wavelength and multi-messenger observations. Finally we outline the capabilities and prospects of detecting VHE emission from GW counterparts.