Towards a few percent measurement of the Hubble constant with the current network of gravitational wave detectors without using electromagnetic information

TL;DR

This paper demonstrates that current and future gravitational wave observations can measure the Hubble constant with increasing precision without electromagnetic data, potentially helping resolve the Hubble tension.

Contribution

It introduces improved population-based methods incorporating complex black hole mass models, achieving higher accuracy in Hubble constant measurements from gravitational wave data.

Findings

30% accuracy improvement with current data

20% accuracy forecast at O4 sensitivity

2.7% accuracy forecast at O5 sensitivity

Abstract

Gravitational waves provide a novel and independent measurement of cosmological parameters, offering a promising avenue to address the Hubble tension alongside traditional electromagnetic observations. In the absence of electromagnetic counterparts or complete host galaxy catalogs, current measurements rely on population-based methods that statistically combine black hole merger events. Building on recent models that incorporate additional structure in the primary black hole mass distribution, using public data from the LIGO-Virgo-KAGRA (LVK) collaboration third observing run (O3), we obtain a 30% accuracy improvement on the measurement of the Hubble constant with respect to the result reported by LVK with the third GW transient catalog (GWTC-3). Employing a realistic simulation that includes full Bayesian single-event inference, we present forecasts for the upcoming LVK observational runs, O4 and O5. Using a three power-law mass model, we project a measurement of the Hubble constant with 20% accuracy at O4 sensitivity, improving to 2.7% accuracy at O5 sensitivity. Our findings demonstrate the potential for gravitational waves to provide a substantial contribution to solving the Hubble tension within the next decade of observations.