Gravitational radiation from the coalescence of binary neutron stars: Effects due to the equation of state, spin, and mass ratio.

Abstract

We calculate the gravitational radiation produced by the coalescence of inspiraling binary neutron stars in the Newtonian regime using three-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 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 $\frac{\mathrm{GM}}{R{c}^{2}}$, the equation of state, and the mass ratio.