Here we show how H0 can be derived purely from the gravitational waves (GW) of neutron star-black hole (NSBH) mergers. This new method provides an estimate of H0 spanning the redshift range, z<0.25 with current GW sensitivity and without the need for any afterglow detection. We utilise the inherently tight neutron star mass function together with the NSBH waveform amplitude and frequency to estimate distance and redshift respectively, thereby obtaining H0 statistically. Our first estimate is H0=86−46+55 km s−1 Mpc−1 for the secure NSBH events GW190426 and GW200115. We forecast that soon, with 10 more such NSBH events we can reach competitive precision of δH0/H0≲20%.
@article{arxiv.2308.02440,
title = {Pure Gravitational Wave Estimation of Hubble's Constant using Neutron Star-Black Hole Mergers},
author = {Leo W. H. Fung and Tom Broadhurst and George F. Smoot},
journal= {arXiv preprint arXiv:2308.02440},
year = {2023}
}