Gravitational Radiation from the Coalescence of Binary Neutron Stars: Effects Due to the Equation of State, Spin, and Mass Ratio

TL;DR

This paper uses 3D numerical simulations to analyze how the equation of state, spin, and mass ratio of binary neutron stars affect the gravitational waves emitted during their coalescence in the Newtonian regime.

Contribution

It provides detailed simulations exploring the impact of neutron star properties on gravitational waveforms, highlighting dependencies on physical parameters.

Findings

Waveforms depend on neutron star radius and equation of state.

Spectra reveal characteristic features related to mass ratio.

Hydrodynamic effects significantly influence gravitational radiation.

Abstract

We calculate the gravitational radiation produced by the coalescence of inspiraling binary neutron stars in the Newtonian regime using 3-dimensional numerical simulations. The stars are modeled as polytropes and start out in the point-mass regime at wide separation. The hydrodynamic integration is performed using smooth particle hydrodynamics (SPH) with Newtonian gravity, and the gravitational radiation is calculated using the quadrupole approximation. We have run a number of simulations varying the neutron star radii, equations of state, spins, and mass ratio. The resulting gravitational waveforms and spectra are rich in information about the hydrodynamics of coalescence, and show characteristic dependence on GM/Rc^2, the equation of state, and the mass ratio.