First measurement of the Hubble constant from gravitational wave-galaxy cross-correlations
arXiv:2512.15380
Abstract
We measure for the first time the Hubble constant () from the cross-correlation of galaxies and gravitational waves (GW), by applying the method. This method consists of finding the peak of the 3D angular cross-spectrum between the galaxy redshifts () and the GW luminosity distances (). Using two GW events from the GWTC-3.0 catalog and the GLADE+ galaxy catalog, we make the first detection of the cross-correlation peak at confidence. This signal comes mostly from the best localized event in the catalog, GW190814, which alone provides a significance. Adding also the multimessenger event GW170817, but without using its known redshift, we find km sMpc and the first observational constraint on the GW bias, at 95\% CI. These measurements set the stage for future novel cosmological constraints with this technique.
7 pages, 3 figures, 2 appendices