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

We present a test of the statistical method introduced by Bernard F. Shutz in 1986 using only gravitational waves to infer the Hubble constant (H0) 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 LB threshold enhances the posterior structure and slightly shifts the distribution's peak to higher H0 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. [ABSTRACT FROM AUTHOR]