A simple model of complete precessing black-hole-binary gravitational waveforms

TL;DR

This paper introduces 'PhenomP', a frequency-domain model for gravitational waves from precessing spinning black-hole binaries, capturing key physics with only three parameters, aiding GW detection and analysis.

Contribution

The paper presents the first frequency-domain precessing binary waveform model using a simplified parameterization, enabling efficient GW data analysis.

Findings

Model accurately reproduces hybrid waveforms across configurations

Requires only three physical parameters for key waveform features

Facilitates GW searches and astrophysical measurements

Abstract

The construction of a model of the gravitational-wave (GW) signal from generic configurations of spinning-black-hole binaries, through inspiral, merger and ringdown, is one of the most pressing theoretical problems in the build-up to the era of GW astronomy. We present the first such model in the frequency domain, "PhenomP", which captures the basic phenomenology of the seven-dimensional parameter space of binary configurations with only three key physical parameters. Two of these (the binary's mass ratio and an effective total spin parallel to the orbital angular momentum, which determines the inspiral rate) define an underlying non-precessing-binary model. The non-precessing-binary waveforms are then "twisted up" with approximate expressions for the precessional motion, which require only one additional physical parameter, an effective precession spin, $\chi_p$. All other parameters (total mass, sky location, orientation and polarisation, and initial phase) can be specified trivially. The model is constructed in the frequency domain, which will be essential for efficient GW searches and source measurements. We have tested the model's fidelity for GW applications by comparison against hybrid post-Newtonian-numerical-relativity waveforms at a variety of configurations --although we did not use these numerical simulations in the construction of the model. Our model can be used to develop GW searches, to study the implications for astrophysical measurements, and as a simple conceptual framework to form the basis of generic-binary waveform modelling in the advanced-detector era.