Population properties and multimessenger prospects of neutron star–black hole mergers following GWTC-3

Neutron star-black hole (NSBH) mergers detected in gravitational waves have the potential to shed light on supernova physics, the dense matter equation of state, and the astrophysical processes that power their potential electromagnetic counterparts. In this talk, we will present constraints on the mass and spin distributions and multimessenger prospects of NSBH systems based on the population of four candidate events detected in gravitational waves so far with a false alarm rate ≤ 1 yr⁻¹. Using an approach driven by gravitational-wave data rather than binary simulations, we will show that fewer than 14% of NSBH mergers detectable in gravitational waves will have an electromagnetic counterpart. Finally, we will describe a method for the multimessenger analysis of NSBH mergers based on the nondetection of an electromagnetic counterpart that allows us to place independent constraints on the neutron star equation of state.