Effect of precession on golden dark sirens

Gravitational-wave observations from binary black hole (BBH) mergers, also called dark sirens, provide an estimate of the luminosity distance. For some dark siren events, the sky position is measured well enough to uniquely identify the host galaxy and measure its redshift. Together with the luminosity distance measurement, this provides a method independent of the cosmic distance ladder to calculate the Hubble-Lemaître constant (H₀). A fraction of these dark siren events can be golden events that individually measure H₀ to better than 2% precision, which is enough to resolve the H₀ tension. In this work, we study the effect of precession in the measurement of H₀ for BBH systems. We also report the number of golden dark siren events that are expected to be detected in the next LIGO-Virgo observing run (O4).