Comparing the inspiral of irrotational and corotational binary neutron stars

TL;DR

This paper models the late inspiral phase of binary neutron stars, comparing irrotational and corotational cases, and highlights significant differences in inspiral rates due to binding energy variations, bridging quasi-equilibrium and full relativistic simulations.

Contribution

It provides a detailed comparison of irrotational and corotational binary neutron star inspirals using a quasi-equilibrium approach, linking numerical results to full relativistic simulations.

Findings

Significant difference in inspiral rate between irrotational and corotational sequences.

Binding energy differences primarily cause the inspiral rate variation.

Method to match quasi-equilibrium waveforms with full relativistic merger simulations.

Abstract

We model the adiabatic inspiral of relativistic binary neutron stars in a quasi-equilibrium (QE) approximation, and compute the gravitational wavetrain from the late phase of the inspiral. We compare corotational and irrotational sequences and find a significant difference in the inspiral rate, which is almost entirely caused by differences in the binding energy. We also compare our results with those of a point-mass post-Newtonian calculation. We illustrate how the late inspiral wavetrain computed with our QE numerical scheme can be matched to the subsequent plunge and merger waveform calculated with a fully relativistic hydrodynamics code.