Cosmology and modified gravity with dark sirens from GWTC-3

Abstract

We present the latest measurements of the Hubble parameter and of the parameter ${\Xi }_0$ describing modified gravitational wave propagation, obtained from the third gravitational wave transient catalog, GWTC-3, using the correlation with galaxy catalogs and information from the source-frame mass distribution of binary black holes. The latter leads to the tightest bound on ${\Xi }_0$ so far, i.e. ${\Xi }_0=1.2_{-0.7}^{+0.7}$ with a flat prior on ${\Xi }_0$, and ${\Xi }_0=1.0_{-0.8}^{+0.4}$ with a prior uniform in $\log {\Xi }_0$ (Max posterior and $68\%$ HDI). The measurement of $H_0$ is dominated by the single bright siren GW170817, resulting in $H_0=67_{-6}^{+9}\mathrm{km}{\mathrm{s}}^{-1}\mathrm{Mpc}$ when combined with the galaxy catalog.

Contribution to the Gravitation session of the 56th Rencontres de Moriond 2022