Modeling the dynamics of tidally-interacting binary neutron stars up to merger

TL;DR

This paper introduces an advanced effective-one-body model for binary neutron star mergers that accurately captures tidal interactions up to the merger, aligning well with numerical relativity simulations.

Contribution

The paper presents the first semi-analytical EOB model that includes tidal amplification effects near merger without fitting parameters.

Findings

Model agrees with numerical relativity within data uncertainties

Captures tidal effects close to merger accurately

Provides the most precise analytical waveforms for neutron star binaries

Abstract

The data analysis of the gravitational wave signals emitted by coalescing neutron star binaries requires the availability of an accurate analytical representation of the dynamics and waveforms of these systems. We propose an effective-one-body (EOB) model that describes the general relativistic dynamics of neutron star binaries from the early inspiral up to merger. Our EOB model incorporates an enhanced attractive tidal potential motivated by recent analytical advances in the post-Newtonian and gravitational self-force description of relativistic tidal interactions. No fitting parameters are introduced for the description of tidal interaction in the late, strong-field dynamics. We compare the model energetics and the gravitational wave phasing with new high-resolution multi-orbit numerical relativity simulations of equal-mass configurations with different equations of state. We find agreement within the uncertainty of the numerical data for all configurations. Our model is the first semi-analytical model which captures the tidal amplification effects close to merger. It thereby provides the most accurate analytical representation of binary neutron star dynamics and waveforms currently available.