GW170817: Joint Constraint on the Neutron Star Equation of State from Multimessenger Observations

TL;DR

This paper combines gravitational wave data and electromagnetic observations from GW170817 to place joint constraints on the neutron star equation of state, narrowing down the possible models by ruling out extreme stiffness or softness.

Contribution

It introduces a combined analysis of multimessenger data and numerical relativity to better constrain neutron star properties.

Findings

Upper bounds on tidal parameters from gravitational waves.

Lower bounds from kilonova modeling and numerical relativity.

Joint constraints exclude extreme neutron star equations of state.

Abstract

Gravitational waves detected from the binary neutron star (NS) merger GW170817 constrained the NS equation of state by placing an upper bound on certain parameters describing the binary's tidal interactions. We show that the interpretation of the UV/optical/infrared counterpart of GW170817 with kilonova models, combined with new numerical relativity results, imply a complementary lower bound on the tidal deformability parameter. The joint constraints tentatively rule out both extremely stiff and soft NS equations of state.