Recovering cosmological parameters from the mock gravitational wave data of the Einstein Telescope

TL;DR

This paper demonstrates that the Einstein Telescope can effectively recover key cosmological parameters like the Hubble constant and matter density using mock gravitational wave data and a simple spectral method.

Contribution

It introduces a fast, effective technique to infer cosmological parameters from gravitational wave data, specifically utilizing the intrinsic chirp mass spectrum of black hole binaries.

Findings

At least one year of ET data can constrain H_0 to 1% uncertainty.

ET can constrain matter density parameter Ω_m to within 4% uncertainty.

The method is effective for standalone ET observations of gravitational wave spectral sirens.

Abstract

Einstein Telescope (ET) is a third-generation gravitational wave (GW) detector with tenfold better sensitivity compared to the advanced LIGO detectors. It will be capable of observing copious stellar mass binary black hole mergers up to a redshift of 10 which will make it especially useful for cosmography. We generate a mock gravitational wave event catalog for the Einstein Telescope and show the recoverability of either the Hubble constant ($H_0$) or the matter density parameter ($\Omega_{\rm m}$). We present a simple, effective and fast technique for inferring $H_0$ (or $\Omega_{\rm m}$) using the intrinsic chirp mass spectrum of black hole binaries, and investigate the efficacy of the method assuming the standard model of cosmology. If only $H_0$ has to be constrained, we find that at least one year of ET's observation will be required to achieve 1% uncertainty. With the same amount of observation, $\Omega_{\rm m}$ can be constrained to within 4% uncertainty. With ET operating as a standalone instrument, we show that the GW spectral sirens detected by it can constrain the Hubble constant.