Prospects for joint gravitational wave and short gamma-ray burst observations

TL;DR

This paper evaluates the expected rates of joint gravitational wave and short gamma-ray burst observations, highlighting the potential for increased detection sensitivity and the importance of detector network evolution and progenitor characteristics.

Contribution

It provides a detailed analysis of how joint observations can improve detection sensitivity and constrain gamma-ray burst progenitor models using upcoming gravitational wave detector data.

Findings

25% increase in GW detection sensitivity when using GRB information

High likelihood of joint detections as detectors reach design sensitivity

Joint observations can help estimate gamma-ray burst jet opening angles

Abstract

We present a detailed evaluation of the expected rate of joint gravitational-wave and short gamma-ray burst (GRB) observations over the coming years. We begin by evaluating the improvement in distance sensitivity of the gravitational wave search that arises from using the GRB observation to restrict the time and sky location of the source. We argue that this gives a 25% increase in sensitivity when compared to an all-sky, all-time search, corresponding to more than doubling the number of detectable gravitational wave signals associated with GRBs. Using this, we present the expected rate of joint observations with the advanced LIGO and Virgo instruments, taking into account the expected evolution of the gravitational wave detector network. We show that in the early advanced gravitational wave detector observing runs, from 2015-2017, there is only a small chance of a joint observation. However, as the detectors approach their design sensitivities, there is a good chance of joint observations provided wide field GRB satellites, such as Fermi and the Interplanetary Network, continue operation. The rate will also depend critically upon the nature of the progenitor, with neutron star--black hole systems observable to greater distances than double neutron star systems. The relative rate of binary mergers and GRBs will depend upon the jet opening angle of GRBs. Consequently, joint observations, as well as accurate measurement of both the GRB rate and binary merger rates, will allow for an improved estimation of the opening angle of GRBs.