Gravitational waveforms of binary neutron star inspirals using post-Newtonian tidal splicing

TL;DR

This paper enhances the tidal splicing model for binary neutron star inspirals by including higher-order tidal effects, dynamical tides, and spin-tidal interactions, using surrogate black hole binary waveforms for efficient gravitational wave signal modeling.

Contribution

It introduces an improved tidal splicing approach incorporating advanced tidal effects and surrogate models, enabling fast and accurate gravitational waveform predictions for neutron star binaries.

Findings

Enhanced tidal splicing model with higher-order effects

Validated models against existing simulations

Enabled rapid waveform generation for data analysis

Abstract

The tidal deformations of neutron stars within an inspiraling compact binary alter the orbital dynamics, imprinting a signature on the gravitational wave signal. Modeling this signal could be done with numerical-relativity simulations, but these are too computationally expensive for many applications. Analytic post-Newtonian treatments are limited by unknown higher-order nontidal terms. This paper further builds upon the "tidal splicing" model in which post-Newtonian tidal terms are "spliced" onto numerical relativity simulations of black-hole binaries. We improve on previous treatments of tidal splicing by including spherical harmonic modes beyond the (2,2) mode, expanding the post-Newtonian expressions for tidal effects to 2.5 order, including dynamical tide corrections, and adding a partial treatment of the spin-tidal dynamics. Furthermore, instead of numerical relativity simulations, we use the spin-aligned binary black hole (BBH) surrogate model "NRHybSur3dq8" to provide the BBH waveforms that are input into the tidal slicing procedure. This allows us to construct spin-aligned, inspiraling TaylorT2 and TaylorT4 splicing waveform models that can be evaluated quickly. These models are tested against existing binary neutron star and black hole-neutron star simulations. We implement the TaylorT2 splicing model as an extension to "NRHybSur3dq8," creating a model that we call "NRHybSur3dq8Tidal."