Orateur
Description
Standard sirens have been the central paradigm in gravitational-wave (GW)
cosmology so far. From the GW signature of compact star binaries, it is
possible to directly measure the luminosity distance of the source.
Since the source redshift cannot be inferred from the GW signal alone,
additional information is required for instance from the observation of
an electromagnetic counterpart. One of the lessons learned during the
last LIGO-Virgo science run O3 is that it may be more difficult than
expected to collect many electromagnetic counterparts of GW events in
the coming years. New techniques and ideas have emerged recently to
exploit another type of observables to obtain an estimate of the source
redshift.
In this talk, I will present an overview of those emerging techniques
along with recent results and future prospects associated to their
application.
I will first review the standard approach based on electromagnetic
observations, either the observation of a counterpart, e.g. a kilonova
transient or the use of galaxy surveys.
I will then turn to techniques that do not require electromagnetic
observations, such as neutron-star tidal deformability models, features
of the source-frame mass spectrum for compact binaries, angular
cross-correlation between galaxy and GW sources distributions, and
cross-correlation or identification of GWs lensing maps.
