Item

Abstract

The combined observation of gravitational and electromagnetic waves from the
coalescence of two neutron stars marks the beginning of multi-messenger
astronomy with gravitational waves (GWs). The development of accurate
gravitational waveform models is a crucial prerequisite to extract information
about the properties of the binary system that generated a detected GW signal.
In binary neutron star systems (BNS), tidal effects also need to be
incorporated in the modeling for an accurate waveform representation. Building
on previous work [Phys.Rev.D96 121501], we explore the performance of
inspiral-merger waveform models that are obtained by adding a numerical
relativity (NR) based approximant for the tidal part of the phasing (NRTidal)
to existing models for nonprecessing and precessing binary black hole systems
(SEOBNRv4, PhenomD and PhenomPv2), as implemented in the LSC Algorithm Library
Suite. The resulting BNS waveforms are compared and contrasted to target
waveforms hybridizing NR waveforms, covering the last approx. 10 orbits up to
merger and extending through the postmerger phase, with inspiral waveforms
calculated from 30Hz obtained with TEOBResumS. The latter is a state-of-the-art
effective-one-body waveform model that blends together tidal and spin effects.
We probe that the combination of the PN-based self-spin terms and of the
NRTidal description is necessary to obtain minimal mismatches (< 0.01) and
phase differences (< 1 rad) with respect to the target waveforms. However, we
also discuss possible improvements and drawbacks of the NRTidal approximant in
its current form, since we find that it tends to overestimate the tidal
interaction with respect to the TEOBResumS model during the inspiral.