Black hole–neutron star binary mergers: the imprint of tidal deformations and debris

Abstract

The increase in the sensitivity of gravitational wave (GW) interferometers will bring additional detections of binary black hole (BBH) and double neutron star (NS) mergers. It will also very likely add many merger events of BH–NS binaries. Distinguishing mixed binaries from BBHs mergers for high mass ratios could be challenging because in this situation the NS coalesces with the BH without experiencing significant disruption. To investigate the transition of mixed binary mergers into those behaving more like BBH coalescences, we present results from merger simulations for different mass ratios. We show how the degree of deformation and disruption of the NS impacts the inspiral and merger dynamics, the properties of the final BH, the accretion disk formed from the circularization of the tidal debris, the GWs, and the strain spectrum and mismatches. The results also show the effectiveness of the initial data method that generalizes the Bowen–York initial data for BH punctures to the case of binaries with NS companions.