Multipole tidal effects in the post-Newtonian gravitational-wave phase of compact binary coalescences

TL;DR

This paper develops a detailed multipole model of tidal effects in gravitational wave phases from compact binary coalescences, improving accuracy over previous models and analyzing their impact on observed neutron star mergers.

Contribution

The paper introduces a multipole tidal phase model including quadrupole, current quadrupole, and octupole moments, enhancing the precision of gravitational wave phase predictions.

Findings

MultipoleTidal produces larger phase shifts than PNTidal.

MultipoleTidal aligns more closely with NRTidalv2, especially for high masses.

Current quadrupole and octupole moments have negligible impact on tidal deformability inference.

Abstract

We present the multipole component form of the gravitational wave tidal phase for compact binary coalescences (MultipoleTidal), which consists of the mass quadrupole, the current quadrupole, and the mass octupole moments. We demonstrate the phase evolution and the phase difference between the tidal multipole moments (MultipoleTidal) and the mass quadrupole (PNTidal) as well as the numerical-relativity calibrated model (NRTidalv2). We find the MultipoleTidal gives a larger phase shift than the PNTidal, and is closer to the NRTidalv2. We compute the matches between waveform models to see the impact of the tidal multipole moments on the gravitational wave phases. We find the MultipoleTidal gives larger matches to the NRTidalv2 than the PNTidal, in particular, for high masses and large tidal deformabilities. We also apply the MultipoleTidal model to binary neutron star coalescence events GW170817 and GW190425. We find that the current quadrupole and the mass octupole moments give no significant impact on the inferred tidal deformability.