Effects of Chiral Effective Field Theory Equation of State on Binary Neutron Star Mergers

TL;DR

This paper uses new chiral effective field theory equations of state in general relativistic simulations of binary neutron star mergers, analyzing gravitational waves, matter ejection, and remnant properties to improve understanding of these astrophysical events.

Contribution

It introduces the BL EOS based on chiral effective field theory into neutron star merger simulations and compares results with older models, providing new insights into post-merger dynamics.

Findings

Different equations of state significantly affect gravitational wave signals.

The amount and velocity of ejected matter vary with the EOS used.

Remnant stability criteria are validated through mass distribution and rotation profiles.

Abstract

We present fully general relativistic simulations of binary neutron star mergers, employing a new zero- temperature chiral effective field theory equation of state, the BL EOS. We offer a comparison with respect to the older GM3 EOS, which is based on standard relativistic mean field theory, and separately determine the impact of the mass. We provide a detailed analysis of the dynamics, with focus on the post-merger phase. For all models, we extract the gravitational wave strain and the post-merger frequency spectrum. Further, we determine the amount, velocity, and polar distribution of ejected matter, and provide estimates for the resulting kilonova signals. We also study the evolution of the disk while it is interacting with the hypermassive remnant, and dis- cuss the merits of different disk mass definitions applicable before collapse, with regard to the mass remaining after BH formation. Finally, we investigate the radial mass distribution and rotation profile of the remnants, which validate previous results and also corroborate a recently proposed stability criterion.