Merging Black Holes: Assessing the Performance of Two Analytic Gravitational Waves Models

TL;DR

This paper evaluates the performance of the Backwards one Body (BoB) analytical model for black hole mergers, comparing it with the Implicit Rotating Source (IRS) model and numerical simulations, highlighting its strengths and limitations.

Contribution

It provides a comprehensive assessment of the BoB model's accuracy and advantages over existing models, including its dependence on less numerical data and its ability to incorporate spin.

Findings

Good frequency agreement with numerical data

Amplitude discrepancies identified

BoB model depends indirectly on numerical data

Abstract

Merging black holes produce the loudest signal in the detectors. However, this is the most difficult signal to accurately predict with analytical techniques. Only computer simulations can account for the nonlinear physics during the collision, but they are inherently complex, costly, and affected by numerical errors. In order to bypass this problem, two analytical models for the merger have been developed: the Implicit Rotating Source (IRS) and the newer Backwards one Body (BoB). In this work, we assess the performance of the BoB model by comparing it with the older IRS model and with the numerical data, identifying its strengths and weaknesses. Our main finding reveals discrepancies in amplitude, but overall excellent accord in frequency. The BoB model is comparable with the IRS and NR simulations, having the added advantage that it depends only indirectly on numerical data, it accounts for spin, and it offers a seamless fit with the analytical formalisms for the inspiral. By independently evaluating and testing those models, we bring evidence of their reproducibility, thus upholding high scientific standards, and make available our implementation, enabling readers to evaluate our results themselves.