Signatures of phase transition in binary neutron star mergers

Abstract

Binary neutron star (BNS) mergers are a promising testing ground for warm highly dense states of matter. During a binary merger, densities are expected to easily exceed the nuclear saturation density. This invites the possibility of the emergence of a quark phase. Any signatures of this phase in the gravitational wave signature of the merger can yield insights into the nature of this high-density QCD phase. We construct a set-up to simulate BNS mergers on Snellius, the Dutch national supercomputer. We provide a construction of a polytropic approximation for a state of the art neutron star EOS, and place these in conversation with earlier polytropic EOS. We then simulate BNS mergers using a polytropic EOS including a phase transition. We compare the BNS merger signal including such a phase transition to those without a phase transition, and show that first order phase transitions have multiple strong signatures