The Mass Distribution of Neutron Stars in Gravitational-wave Binaries

TL;DR

This paper infers the mass distribution of neutron stars in gravitational-wave binaries, revealing a uniform distribution with a higher occurrence of massive neutron stars, consistent with Galactic observations.

Contribution

First inference of the extragalactic neutron star mass distribution from gravitational-wave data, highlighting differences from the Galactic population.

Findings

Neutron star masses in gravitational-wave binaries are consistent with a uniform distribution.

Higher prevalence of high-mass neutron stars in gravitational-wave observations.

Maximum neutron star mass aligns with Galactic measurements and dense matter models.

Abstract

The discovery of two neutron star-black hole coalescences by LIGO and Virgo brings the total number of likely neutron stars observed in gravitational waves to six. We perform the first inference of the mass distribution of this extragalactic population of neutron stars. In contrast to the bimodal Galactic population detected primarily as radio pulsars, the masses of neutron stars in gravitational-wave binaries are thus far consistent with a uniform distribution, with a greater prevalence of high-mass neutron stars. The maximum mass in the gravitational-wave population agrees with that inferred from the neutron stars in our Galaxy and with expectations from dense matter.