Estimating the binary neutron star merger rate density evolution with Einstein Telescope

TL;DR

This paper proposes a method to accurately estimate the evolution of binary neutron star merger rates with the Einstein Telescope, accounting for undetected events and reconstructing true rates up to redshift 2.

Contribution

It introduces a scheme to estimate detection efficiency and reconstruct the true BNS merger rate density as a function of redshift using ET data.

Findings

Can reconstruct merger rate density up to z~2

Achieves 12% relative error at z~2

Effective despite significant undetected BNSs

Abstract

The Einstein Telescope (ET) is a proposed third-generation, wide-band gravitational wave (GW) detector which will have an improved detection sensitivity in low frequencies, leading to a longer observation time in the detection band and higher detection rate for binary neutron stars (BNSs). Despite the fact that ET will have a higher detection rate, a large fraction of BNSs will remain undetectable. We present a scheme to estimate accurate detection efficiency and to reconstruct the true merger rate density of the population of the BNSs, as a function of redshift. We show that with ET as a single instrumnet, for a population of BNSs with $R_{mer} \sim 100 (300)$ $\rm Gpc^{-3} yr^{-1}$ at $z\sim 0(2)$, we can reconstruct the merger rate density uptil $z \sim 2$ , with a relative error of $12\%$ at ($z \sim 2$), despite the loss in detection of the bulk of the BNS population.