Source Confusion from Neutron Star Binaries in Third-Generation Ground-Based Gravitational-Wave Detectors*

In this talk, we investigate the overlapping of binary neutron star (BNS) signals in third-generation (3G) gravitational-wave detectors, including the Einstein Telescope (ET) and Cosmic Explorer (CE). Our focus is on assessing the number of occurrence and impact of simultaneous time-frequency overlaps—situations where signals occupy the same frequency bin concurrently, resulting in non-zero cross-correlation. The anticipated improvement in low-frequency sensitivity of these detectors suggests that signals could be detectable for durations ranging from minutes to hours. Through population simulations, we find that such overlaps predominantly occur at lower frequencies, and we propose the use of a signal adapted non-uniform time-frequency grid to effectively monitor overlap occurrences. This approach reveals that simultaneous overlaps in both time and frequency are considerably less common than overlaps in either domain alone. Further, our analysis indicates that the influence of these overlaps on the accuracy of parameter estimation is minimal. Parameter uncertainties for a target signal in the population simulations typically rise by less than 1%, irrespective of the number of signals overlapping the target. Source confusion, a significant concern for space-based detectors, is going to be far milder in ground-based detectors.