Merger remnant and eccentricity dynamics surrogates for eccentric nonspinning black hole binaries

TL;DR

This paper introduces two new surrogate models trained on numerical relativity simulations to predict remnant properties and eccentricity evolution of unequal-mass, non-spinning eccentric binary black holes, aiding gravitational-wave analysis.

Contribution

The paper presents the first models for remnant properties and eccentricity dynamics specifically for eccentric, non-spinning binary black holes, trained on a comprehensive NR simulation dataset.

Findings

Models accurately predict remnant mass, spin, and recoil for eccentric binaries.

Eccentricity impacts remnant properties and recoil, with quantifiable effects.

Error estimates support reliable use in gravitational-wave data analysis.

Abstract

Accurate models of merger remnants are increasingly important for gravitational-wave science, including precision tests of gravity with ringdown, inference of black-hole populations, and modeling hierarchical mergers. For eccentric binaries, remnant mass, spin, and recoil carry nontrivial imprints of eccentricity that are both physically informative and more challenging to model, yet remain less developed than in the quasi-circular case. We present two new models trained on numerical-relativity (NR) simulations of unequal-mass, non-spinning eccentric binary black holes: NRSurE_q4NoSpin_Remnant, which predicts remnant properties, and NRSurE_q4NoSpin_Dynamics, a time-domain surrogate for the evolution of eccentricity and mean anomaly. Both models are trained on NR simulations over a three-dimensional parameter space with mass ratios $q \leq 4$, eccentricity $e < 0.23$, and mean anomaly $\ell \in [0,2\pi)$ radians, where both $e$ and $\ell$ defined at $t=-1000M$ relative to peak amplitude and $M$ is the total mass. We highlight some applications, including the phenomenological impact of eccentricity on remnant properties and the enhancement or suppression of recoil. We also provide error estimates for all modeled quantities, supporting reliable use in current and future gravitational-wave parameter-estimation analyses. Both models will be made available through open-source codes.