Measurement of the Hubble constant using the Dark Energy Survey Year 6 Gold galaxy catalog and the fourth Gravitational-Wave Transient Catalog

TL;DR

This paper measures the Hubble constant using gravitational wave data and galaxy catalogs, demonstrating the potential and challenges of dark siren methods with deep galaxy surveys.

Contribution

It introduces a method combining GW data with the DES Year 6 galaxy catalog to estimate H0, addressing catalog biases and selection effects.

Findings

H0 estimated as 70.9^{+22.3}_{-18.6} km/s/Mpc from dark sirens

Combined H0 estimate with GW170817 as 73.1^{+11.7}_{-8.6} km/s/Mpc

Identifies galaxy catalog features that can bias H0 inference.

Abstract

Gravitational wave standard sirens enable independent measurements of the Hubble constant $H_0$. In the absence of electromagnetic counterparts, the "dark siren" method statistically correlates GW events with potential host galaxies. We present a measurement of $H_0$ using 142 compact binary coalescences from the fourth Gravitational-Wave Transient Catalog (GWTC-4.0) combined with the Dark Energy Survey Year 6 Gold photometric galaxy catalog. Using the gwcosmo pipeline, we jointly infer cosmological and GW population parameters. We analyze the impact of galaxy catalog properties on the inference, identifying significant features in the galaxy redshift distribution which can introduce biases. By restricting the galaxy catalog to $0.05<z<0.35$ to maintain consistency with a uniform in comoving volume galaxy distribution, we obtain a result of $H_0 = 70.9^{+22.3}_{-18.6}\;\text{km}\;\text{s}^{-1}\;\text{Mpc}^{-1}$ from dark sirens and $H_0=73.1^{+11.7}_{-8.6}\;\text{km}\;\text{s}^{-1}\;\text{Mpc}^{-1}$ when combined with the bright siren GW170817. This study demonstrates the adaptation of deep galaxy catalogs for GW cosmology, highlighting key challenges and methodologies essential for maximizing the potential of next-generation galaxy surveys.