Impact of the tidal p-g instability on the gravitational wave signal from coalescing binary neutron stars

TL;DR

This paper models the impact of tidal p-g mode instabilities on gravitational wave signals from neutron star mergers, showing potential detection biases and proposing waveform modifications to improve analysis.

Contribution

It introduces a simple saturation model for the p-g instability and assesses its effects on gravitational wave detection and parameter estimation.

Findings

Current detectors may miss over 70% of events if instability effects are ignored.

Instability can bias measurements of masses and distances.

Simple waveform modifications can mitigate these biases.

Abstract

Recent studies suggest that coalescing neutron stars are subject to a fluid instability involving the nonlinear coupling of the tide to $p$-modes and $g$-modes. Its influence on the inspiral dynamics and thus the gravitational wave signal is, however, uncertain because we do not know precisely how the instability saturates. Here we construct a simple, physically motivated model of the saturation that allows us to explore the instability's impact as a function of the model parameters. We find that for plausible assumptions about the saturation, current gravitational wave detectors might miss $> 70\%$ of events if only point particle waveforms are used. Parameters such as the chirp mass, component masses, and luminosity distance might also be significantly biased. On the other hand, we find that relatively simple modifications to the point particle waveform can alleviate these problems and enhance the science that emerges from the detection of binary neutron stars.