# Closed-form tidal approximants for binary neutron star gravitational waveforms constructed from high-resolution numerical relativity simulations

## TL;DR

This paper develops accurate, closed-form gravitational wave models incorporating tidal effects for binary neutron star mergers, based on high-resolution numerical relativity data, suitable for detection and analysis.

## Contribution

It introduces a new method combining NR simulations and effective post-Newtonian expressions to produce comprehensive tidal waveform approximants.

## Key findings

- Waveform models valid from low to merger frequencies.
- Models can be added to black hole waveforms for neutron star binaries.
- High accuracy and flexibility in waveform construction.

## Abstract

We construct closed-form gravitational waveforms (GWs) with tidal effects for the coalescence and merger of binary neutron stars. The method relies on a new set of eccentricity-reduced and high-resolution numerical relativity (NR) simulations and is composed of three steps. First, tidal contributions to the GW phase are extracted from the time-domain NR data. Second, those contributions are employed to fix high-order coefficients in an effective and resummed post-Newtonian expression. Third, frequency-domain tidal approximants are built using the stationary phase approximation. Our tidal approximants are valid from the low frequencies to the strong-field regime and up to merger. They can be analytically added to any binary black hole GW model to obtain a binary neutron star waveform, either in the time or in the frequency domain. This work provides simple, flexible, and accurate models ready to be used in both searches and parameter estimation of binary neutron star events.