Orateur
Description
Gravitational waves from inspiraling compact binaries provide direct measurements of luminosity distances and serve as a powerful probe of the high-redshift Universe. In addition to their role as standard sirens, they offer an opportunity to constrain small-scale density fluctuations through the dispersion in the distance-redshift relation induced by gravitational lensing. In this talk, we propose a method to constrain this lensing dispersion without requiring redshift information by analyzing the angular clustering of gravitational-wave sources. Our formalism, which incorporates second-order lensing effects in the luminosity distance, shows that the amplitude of the auto-correlation angular clustering decreases with increasing lensing dispersion. While we demonstrate that the auto-correlation signal is detectable with sufficient signal-to-noise ratios in future gravitational wave experiments, a strong degeneracy exists between the lensing dispersion and the linear bias of gravitational wave sources. We demonstrate that this degeneracy is partially broken by a joint analysis of the autocorrelation of gravitational wave sources and the cross-correlation with galaxies whose redshifts are known.