First measurement of the Hubble constant from a combined weak lensing and gravitational-wave standard siren analysis
We present a new measurement of the Hubble constant ($H_0$) resulting from the first joint analysis of standard sirens with weak gravitational lensing and galaxy clustering observables comprising three two-point correlation functions (3$\times$2pt). For the 3$\times$2pt component of the analysis, we use data from the Dark Energy Survey (DES) Year 3 release. For the standard sirens component, we use data from the Gravitational-Wave Transient Catalog 4.0 released by the LIGO-Virgo-KAGRA (LVK) Collaboration. For GW170817, the only standard siren for which extensive electromagnetic follow-up observations exist, we also use measurements of the host galaxy redshift and inclination angle estimates derived from observations of a superluminal jet from its remnant. Our joint analysis yields $H_0 = 67.9^{+4.4}_{-4.3}$~km~s$^{-1}$~Mpc$^{-1}$, a $6.4\%$ measurement, while improving the DES constraint on the total abundance of matter $\Omega_m$ by $22\%$. Removing the jet information degrades the $H_0$ precision to $9.9\%$. The measurement of $H_0$ remains a central problem in cosmology with a multitude of approaches being vigorously pursued in the community aiming to reconcile significantly discrepant measurements at the percent-level. In light of the impending new data releases from DES and LVK, and anticipating much more constraining power from 3$\times$2pt observables using newly commissioned survey instruments, we demonstrate that incorporating standard sirens into the cosmology framework of large cosmic surveys is a viable route towards that goal.