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

Understand

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.