Cosmology with gravitational wave standard sirens: current results and future perspectives

ABSTRACT: I will introduce the concept of standard siren, reviewing the methodologies that one can apply to probe the cosmic expansion using gravitational wave observations. I will then outline the gravitational wave sources that can be used as standard sirens for both Earth-based (LIGO/Virgo) and space-based (LISA) detectors, pointing out for which of them an electromagnetic counterpart is expected to be observed. I will then discuss the constraints on the Hubble constant recently obtained from LIGO/Virgo observations and discuss future cosmological prospects for Earth-based detectors. Finally I will present cosmological forecasts for LISA, which will be able to probe the expansion of the universe at high redshift and efficiently test deviations from LCDM.