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 (3times2pt). For the 3times2pt component of the analysis, we used data from the Dark Energy Survey (DES) Year 3 release. For the standard siren component, we used 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 used measurements of the host galaxy redshift and inclination angle estimates derived from observations of a superluminal jet from its remnant. Assuming a flat Λ cold dark matter model, our joint analysis yields km s H_0 = 67.94^ +4.40 _ -4.34 -1 $ Mpc^-1, a 6.4% measurement, while improving the DES constraint on the total abundance of matter Ω_m by 22%. When the jet information is removed, the H_0 precision decreases to 9.9%. The measurement of $H_0 remains a central problem in cosmology, with a multitude of approaches being vigorously pursued with the aim to reconcile significantly discrepant measurements at the percent level. In light of the impending new data releases from DES and LVK, and anticipating a much higher constraining power from 3times2pt observables using newly commissioned survey instruments, we demonstrate that incorporating standard sirens in the cosmology framework of large cosmic surveys is a viable route towards that goal.