Prospects for Measuring the Hubble Constant with Neutron-Star-Black-Hole Mergers

TL;DR

This paper evaluates the potential of neutron-star-black-hole mergers observed via gravitational waves and electromagnetic signals to precisely measure the Hubble constant, aiming to resolve current measurement tensions.

Contribution

It presents the first end-to-end analysis of realistic NSBH populations incorporating both GW and EM detection, estimating future $H_0$ measurement precision.

Findings

NSBH mergers could achieve 1.5-2.4% $H_0$ precision by 2030

Measurement accuracy depends on spin precession and tidal disruption modeling

Simulations show potential to resolve current $H_0$ tension.

Abstract

Gravitational wave (GW) and electromagnetic (EM) observations of neutron-star-black-hole (NSBH) mergers can provide precise local measurements of the Hubble constant ($H_0$), ideal for resolving the current $H_0$ tension. We perform end-to-end analyses of realistic populations of simulated NSBHs, incorporating both GW and EM selection for the first time. We show that NSBHs could achieve unbiased 1.5-2.4% precision $H_0$ estimates by 2030. The achievable precision is strongly affected by the details of spin precession and tidal disruption, highlighting the need for improved modeling of NSBH mergers.