Dark standard siren cosmology with bright galaxy subsets

TL;DR

This paper explores how selecting bright galaxy subsets can significantly improve the precision of dark standard siren measurements of the Hubble constant, potentially up to 80%, by using gravitational-wave data and galaxy catalogues.

Contribution

It demonstrates that focusing on bright galaxy subsets enhances $H_0$ measurement precision and suggests using alternative tracers at higher redshifts.

Findings

Bright galaxy subsets can improve $H_0$ precision by up to 80%.

Using bright galaxies as tracers is promising for gravitational-wave cosmology.

Systematic uncertainties still need thorough assessment.

Abstract

In this short paper, we investigate the impact of selecting only a subset of bright galaxies to provide redshift information for a dark standard siren measurement of the Hubble constant $H_0$. Employing gravitational-wave observations from the Third Gravitational-Wave Transient Catalogue (GWTC-3) in conjunction with the GLADE+ galaxy catalogue, we show that restricting to bright galaxy subsets can enhance the precision of the $H_0$ estimate by up to $80\%$ in the most favorable scenario. A comprehensive assessment of systematic uncertainties is still required. This work lays the foundation for employing alternative tracers -- such as brightest cluster galaxies (BCGs) and luminous red galaxies (LRGs) -- in gravitational-wave cosmology, particularly at redshifts where conventional galaxy catalogues offer limited coverage.