Using gravitational-wave observations and quasi-universal relations to constrain the maximum mass of neutron stars

Abstract

Combining the gravitational-wave observations of merging systems of binary neutron stars and quasi-universal relations we set constraints on the maximum mass that can be attained by nonrotating stellar models of neutron stars. More specifically, exploiting the recent observation of the gravitational-wave event GW170817 (Abbott et al. 2017b) and the quasi-universal relation between the maximum mass of nonrotating stellar models $M_{\rm TOV}$ and the maximum mass that can be supported through uniform rotation $M_{\rm max} = \left(1.203 \pm 0.022\right) M_{\rm TOV}$ (Breu & Rezzolla 2016), we set limits for the maximum mass to be $2.01 \pm 0.04 \leq M_{\rm TOV}/M_{\odot} \lesssim 2.16 \pm 0.03$, where the lower limit in this range comes from pulsar observations (Antoniadis et al. 2013). Our estimate, which follows a very simple line of arguments and does not rely on the interpretation of the electromagnetic signal, can be further refined as new detections become available. We also briefly discuss the impact that our conclusions have on the equation of state of nuclear matter.