Eccentric Black Hole-Neutron Star Mergers

TL;DR

This paper investigates black hole-neutron star mergers through relativistic simulations, exploring how different impact parameters influence gravitational wave signals and merger outcomes, including disk formation and unbound material.

Contribution

It provides the first detailed relativistic simulations of eccentric BH-NS mergers with varying impact parameters, revealing diverse observational signatures.

Findings

Significant variation in GW signatures based on impact parameters

Different merger outcomes affect accretion disk mass and unbound material

Eccentric mergers produce richer phenomenology than circular ones

Abstract

Within the next few years gravitational waves (GWs) from merging black holes (BHs) and neutron stars (NSs) may be directly detected, making a thorough theoretical understanding of these systems a high priority. As an additional motivation, these systems may represent a subset of short-duration gamma-ray burst (sGRB) progenitors. BH-NS mergers are expected to result from primordial, quasi-circular inspiral as well as dynamically formed capture binaries. The latter channel allows mergers with high eccentricity, resulting in a richer variety of outcomes. We perform general relativistic simulations of BH-NS interactions with a range of impact parameters, and find significant variation in the properties of these events that have potentially observable consequences, namely the GW signature, remnant accretion disk mass, and amount of unbound material.