Will black hole-neutron star binary inspirals tell us about the neutron star equation of state?

TL;DR

This paper investigates whether gravitational wave signals from black hole-neutron star binaries can provide insights into the neutron star's internal structure and equation of state, considering detector sensitivities and tidal effects.

Contribution

It demonstrates that current detection templates are sufficient for inspiral detection and assesses the potential to constrain neutron star equations of state from gravitational wave data.

Findings

Detection loss below 1% with current templates

Can constrain stiff equations of state

Cannot distinguish soft equations of state

Abstract

The strong tidal forces that arise during the last stages of the life of a black hole-neutron star binary may severely distort, and possibly disrupt, the star. Both phenomena will imprint signatures about the stellar structure in the emitted gravitational radiation. The information from the disruption, however, is confined to very high frequencies, where detectors are not very sensitive. We thus assess whether the lack of tidal distortion corrections in data-analysis pipelines will affect the detection of the inspiral part of the signal and whether these may yield information on the equation of state of matter at nuclear densities. Using recent post-Newtonian expressions and realistic equations of state to model these scenarios, we find that point-particle templates are sufficient for the detection of black hole-neutron star inspiralling binaries, with a loss of signals below 1% for both second and third-generation detectors. Such detections may be able to constrain particularly stiff equations of state, but will be unable to reveal the presence of a neutron star with a soft equation of state.