Impacts of overlapping gravitational-wave signals on the parameter estimation: Toward the search for cosmological backgrounds

Understand

Third-generation gravitational wave detectors, such as the Einstein Telescope and Cosmic Explorer, will detect a bunch of gravitational-wave (GW) signals originating from the coalescence of binary neutron star (BNS) and binary black hole (BBH) systems out to the higher redshifts, $z\sim 5-10$.

• There is a potential concern that some of the GW signals detected at a high statistical significance eventually overlap with each other, and the parameter estimation of such an overlapping system can differ from the one expected from a single event.
• Also, there are certainly overlapping systems in which one of the overlapping events has a low signal-to-noise ratio $\lesssim 4$, and is thus unable to be clearly detected.
• Those system will potentially be misidentified with a single GW event, and the estimated parameters of binary GWs can be biased.