Speaker
Description
A yet elusive class of sources of GWs are stochastic backgrounds. Such signals can be originated either by the incoherent superimposition of unresolved signals of astrophysical origin, or by several processes in the very early Universe. Detecting the latter kind of signal would thus be of pivotal importance to understand the phenomena happening right after the Big Bang.
Third-generation detectors, Einstein Telescope and Cosmic Explorer, thanks to an increase of more than one order of magnitude in sensitivity and a larger bandwidth will have an outstanding potential in this direction. The subtraction of the astrophysical foreground to reveal an underlying cosmological stochastic background will anyway pose a significant challenge.
After showing a recent derivation of the spectral features of the astrophysical background generated by a finite population of sources, we will present a novel approach for characterizing this astrophysical 'confusion noise' and residuals from the subtraction of resolved ones, where we average the cross-correlated partially cleaned detectors’ outputs over many noise realizations.
Crucially, we stress that the masking effect of the astrophysical foreground depends on the specific cosmological search conducted through the employed filter function. We show that, in a network comprising Einstein Telescope and two Cosmic Explorers, black hole binaries do not compromise the sensitivity to cosmological searches; while the effect of neutron star binaries is more substantial.