APEC Seminar (Astronomy - Particle Physics - Experimental Physics - Cosmology)

Speaker: Surhud More (IUCAA)
Title: Inference of the Hubble constant from BBH-galaxy cross-correlations
Date (JST): Thu, Aug 27, 2020, 11:00 - 12:00
Place: Zoom
Abstract: There exists an uncomfortable discrepancy between the Hubble constant obtained from the early and late Universe probes. Is this discrepancy related to unknown systematics in the low (or high) redshift probes, or does this discrepancy have a physical origin? Gravitational wave observations act as standard sirens and hold a potential to help answer this question. The most obvious case corresponds to binary neutron star mergers, such as GW170817, which have been detected in the electromagnetic spectrum. However, one can statistically use binary black holes without an electromagnetic counterpart by cross-correlating their positions with galaxies with known redshifts.
I will review the current state of the art method which has been used on real data by the LIGO-Virgo Collaboration. I will present an alternative method which relies on the clustering of galaxies and the BBH sources, and how the use of such a method can resolve issues related to galaxy catalog incompleteness.
Remarks: <Slides>