Speaker
Description
Observations of gravitational waves (GWs) from dark sirens measures source locations and distances, whereas galaxies have precise angular positions but no direct measurement of their distances -- only redshifts. By cross-correlating GWs from binary black hole mergers, in spherical shells of luminosity distance DL, with galaxies in shells of redshift z, we project a direct measurement of the Hubble diagram DL(z). Since this standard ruler relies only on the statistical proximity of dark sirens and galaxies, our method (dubbed "Peak Sirens") is essentially model-independent.
We make forecast for the method for the observation run 5 of LIGO-Virgo-KAGRA (LVK), as well as for the third-generation observatories Einstein Telescope and Cosmic Explorer. We employ thousands of full-sky light cone simulations with realistic numbers for the tracers, and include masking by the Milky Way, lensing and inhomogeneous GW sky coverage.
We show that future third-generation GW detectors can achieve sub-percent uncertainties in H0 assuming LCDM, and 3% in a more flexible w0waCDM model. The method also shows remarkable robustness against systematic effects such as the modeling of non-linear structure formation.
