Time domain phenomenological model of gravitational wave subdominant harmonics for quasi-circular non-precessing binary black hole coalescences

TL;DR

This paper extends a time domain phenomenological model for gravitational waves from binary black hole mergers to include subdominant harmonics and improves the dominant mode modeling, calibrated with numerical relativity and Teukolsky solutions.

Contribution

It introduces an extended time domain model including multiple subdominant harmonics and enhances the dominant mode, calibrated across a wide range of mass ratios.

Findings

Model includes subdominant harmonics $(l=2, m=\pm 1)$, $(l=3, m=\pm 3)$, $(l=4, m=\pm 4)$, $(l=5, m=\pm 5)$.

Calibrated to numerical relativity solutions up to mass ratio 18.

Provides a computationally efficient alternative to frequency domain models.

Abstract

In this work we present an extension of the time domain phenomenological model IMRPhenomT for gravitational wave signals from binary black hole coalescences to include subdominant harmonics, specifically the $(l=2, m=\pm 1)$, $(l=3, m=\pm 3)$, $(l=4, m=\pm 4)$ and $(l=5, m=\pm 5)$ spherical harmonics. We also improve our model for the dominant $(l=2, m=\pm 2)$ mode and discuss mode mixing for the $(l=3, m=\pm 2)$ mode. The model is calibrated to numerical relativity solutions of the full Einstein equations up to mass ratio 18, and to numerical solutions of the Teukolsky equations for higher mass ratios. This work complements the latest generation of traditional frequency domain phenomenological models (IMRPhenomX), and provides new avenues to develop computationally efficient models for gravitational wave signals from generic compact binaries.