Disentangling Spin-induced Precession vs. Eccentricity in GW190521 and GW231123
Abstract
We use the more than 2000 full numerical-relativity simulations included in the fifth release of the RIT binary-black-hole waveform catalog to perform Bayesian parameter estimation, via the rapid iterative fitting algorithm (RIFT), for the gravitational-wave events GW190521 and GW231123. We revisit GW190521, which has previously been identified as potentially possessing large eccentricity upon entering the detector band at 20 Hz, and confirm this finding: the highest likelihood is obtained from waveforms that are simultaneously eccentric and spin-precessing, yielding e20 =0.207−0.147+0.192 and χ1,⊥=0.717−0.406+0.194. Applying the same simulation pool to GW231123, we likewise find a preference for spin precession where at 20 Hz χ1,⊥=0.678−0.462+0.218, but in this case with negligible eccentricity at both 10 Hz and 20 Hz, with e10=0.097−0.073+0.124 and e20=0.056−0.045+0.059. For comparison, both events are also analyzed using exclusively non-precessing (eccentric and quasi-circular) simulations, which yield lower likelihoods in each case. These results indicate that our approach is capable of discriminating between the effects of eccentricity and spin precession in current gravitational-wave signals. The singled out top peak likelihood NR simulations give estimates of the recoil velocities of the merged final holes of 3965km/s for GW190521, and of 2059km/s for GW231123.
Related
- Evidence for orbital eccentricity supports a hierarchical origin for GW231123
- Eccentricity in Disguise? Insights from GW231123 and Numerically Simulated Binary Black Hole Merger Signals
- Toward a complete understanding of the properties of GW190521
- Impact of boundary conditions on onset and symmetry of precession-driven dynamos
- Non-local Stabilization and Synchronization of Larmor Precession in Trapped Polariton Condensate Dimer
BibTeX
@misc{mcmillin2026disentangling,
title = {{Disentangling Spin-induced Precession vs. Eccentricity in GW190521 and GW231123}},
author = {Patricia McMillin and Giuseppe Ficarra and Carlos O. Lousto and Richard O'Shaughnessy},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40077},
eprint = {2610.40077},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40077},
}
RIS
TY - UNPB
TI - Disentangling Spin-induced Precession vs. Eccentricity in GW190521 and GW231123
AU - Patricia McMillin
AU - Giuseppe Ficarra
AU - Carlos O. Lousto
AU - Richard O'Shaughnessy
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40077
UR - https://arxiv.org/abs/2610.40077
AB - We use the more than 2000 full numerical-relativity simulations included in the fifth release of the RIT binary-black-hole waveform catalog to perform Bayesian parameter estimation, via the rapid iterative fitting algorithm (RIFT), for the gravitational-wave events GW190521 and GW231123. We revisit GW190521, which has previously been identified as potentially possessing large eccentricity upon entering the detector band at 20 Hz, and confirm this finding: the highest likelihood is obtained from waveforms that are simultaneously eccentric and spin-precessing, yielding e_20 =0.207_−0.147^+0.192 and χ_1,⊥=0.717_−0.406^+0.194. Applying the same simulation pool to GW231123, we likewise find a preference for spin precession where at 20 Hz χ_1,⊥=0.678_−0.462^+0.218, but in this case with negligible eccentricity at both 10 Hz and 20 Hz, with e_10=0.097_−0.073^+0.124 and e_20=0.056_−0.045^+0.059. For comparison, both events are also analyzed using exclusively non-precessing (eccentric and quasi-circular) simulations, which yield lower likelihoods in each case. These results indicate that our approach is capable of discriminating between the effects of eccentricity and spin precession in current gravitational-wave signals. The singled out top peak likelihood NR simulations give estimates of the recoil velocities of the merged final holes of 3965km/s for GW190521, and of 2059km/s for GW231123.
ER -