Fast frequency-domain gravitational waveforms for precessing binaries with a new twist

TL;DR

This paper introduces a new frequency-domain approach for precessing gravitational waveforms that improves accuracy and efficiency, enhancing parameter estimation for binary merger signals.

Contribution

A novel frequency-domain description of the twisting-up method for precessing waveforms, improving match quality and computational performance.

Findings

Enhanced waveform matches with numerical relativity

Maintains computational efficiency

Reliable in parameter estimation analyses

Abstract

Gravitational waveform (GW) models are a core ingredient for the analysis of compact binary mergers observed by current ground-based interferometers. We focus here on a specific class of such models known as PhenomX, which has gained popularity in recent years thanks to its computational efficiency. We introduce a new description of the ``twisting-up'' mapping underpinning the construction of precessing waveforms within this family. The new description is an adaptation to the frequency domain of a technique previously implemented in time-domain models, where the orbit-averaged post-Newtonian spin-precession dynamics is numerically solved on the fly. We also present an improved version of the gravitational-wave strain amplitudes approximating the signal in the co-precessing frame. We demonstrate that the new description yields improved matches against numerical relativity simulations, with only a modest computational overhead. We also show that the new model can be reliably employed in parameter estimation follow-ups of GW events, returning equivalent or more stringent measurements of the source properties compared to its predecessor.