10th International Conference on Gravitation and Cosmology: New Horizons and Singularities in Gravity (ICGC 2023)

Bayesian framework to infer the Hubble constant from cross-correlation of individual gravitational wave events with galaxies

Not scheduled

15m

IIT Guwahati

Oral Gravitational Waves Gravitational Waves

Speaker

Mr Tathagata Ghosh (Inter-University Centre for Astronomy and Astrophysics)

Description

Gravitational waves (GW) from the inspiral of binary compact objects offer a one-step measurement of the luminosity distance to the event, which is essential for estimating the Hubble constant, $H_0$, that characterizes the expansion rate of the Universe. However, unlike binary neutron stars, the inspiral of binary black holes is not expected to be accompanied by electromagnetic radiation and, thus, a subsequent determination of its redshift using the traditional host identification method is not possible. Consequently, independent redshift measurements of such GW events are necessary to measure $H_0$. In this study, we present a novel Bayesian approach to infer $H_0$ from the cross-correlation between galaxies with known redshifts and individual binary black hole merger events. We demonstrate the efficacy of our method with $250$ simulated GW events distributed within $1$ Gpc in colored Gaussian noise of Advanced LIGO and Advanced Virgo detectors operating at O4 sensitivity. We show that such measurements can constrain the Hubble constant with a precision of $\lesssim 10\mathrm{\%}$ ($90\mathrm{\%}$ highest density interval). We highlight the potential improvements that are required before the method can be applied to real data.