Measuring the distance-redshift relation with the cross-correlation of gravitational wave standard sirens and galaxies

TL;DR

This paper proposes using the cross-correlation between gravitational wave sources and galaxies to measure the distance-redshift relation, enabling constraints on cosmological parameters without relying on electromagnetic counterparts.

Contribution

It introduces a novel method leveraging cross-correlation analysis of gravitational wave sources and galaxy distributions, including lensing effects, to determine cosmological distances.

Findings

Next-generation observations can tightly constrain the distance-redshift relation.

The method can improve measurements of the Hubble constant and dark energy parameters.

Inclusion of weak lensing effects enhances the analysis accuracy.

Abstract

Gravitational waves from inspiraling compact binaries are known to be an excellent absolute distance indicator, yet it is unclear whether electromagnetic counterparts of these events are securely identified for measuring their redshifts, especially in the case of black hole-black hole mergers such as the one recently observed with the Advanced LIGO. We propose to use the cross-correlation between spatial distributions of gravitational wave sources and galaxies with known redshifts as an alternative means of constraining the distance-redshift relation from gravitational waves. In our analysis, we explicitly include the modulation of the distribution of gravitational wave sources due to weak gravitational lensing. We show that the cross-correlation analysis in next-generation observations will be able to tightly constrain the relation between the absolute distance and the redshift, and therefore constrain the Hubble constant as well as dark energy parameters.