A Measurement of the Hubble Constant Using Gravitational Waves from the Binary Merger GW190814

Abstract We present a test of the statistical method introduced by Bernard F. Shutz in 1986 using only gravitational waves to infer the Hubble constant (H 0 ) from GW190814, the first high-probability neutron-star–black hole (NS–BH) merger candidate detected by the Laser Interferometer gravitational-wave Observatory (LIGO) and the Virgo interferometer. We apply a baseline test of this method to the binary neutron star (BNS) merger GW170817 and find km s −1 Mpc −1 (maximum a posteriori and 68.3% highest density posterior interval) for a galaxy B -band luminosity threshold of with a correction for catalog incompleteness. Repeating the calculation for GW190814, we obtain km s −1 Mpc −1 and km s −1 Mpc −1 for and , respectively. Combining the posteriors for both events yields km s −1 Mpc −1 , demonstrating the improvement on constraints when using multiple gravitational-wave events. We also confirm the results of other works that adopt this method, showing that increasing the L B threshold enhances the posterior structure and slightly shifts the distribution’s peak to higher H 0 values.We repeat the joint inference using the low-spin PhenomPNRT and the newly available combined (SEOBNRv4PHM + IMRPhenomPv3HM) posterior samples for GW170817 and GW190814, respectively, achieving a tighter constraint of km s −1 Mpc −1 .