Eccentricity signatures in LIGO-Virgo-KAGRA's BNS and NSBH binaries

Keisi Kacanja¹, Kanchan Soni¹, Alexander H. Nitz¹

_{1. Department of Physics, Syracuse University, Crouse Dr, Syracuse, NY 13210}

Introduction

This project focuses on measuring the orbital eccentricity of low-mass binary systems using gravitational wave data from LIGO and Virgo’s first four observing runs. We analyze six events with a new eccentric waveform model, SEOBNRv5EHM, and compare results to the existing TEOBResumS-Dali model, including the first eccentricity constraints for GW190814. By incorporating higher-order modes and optimizing Bayesian inference through efficient marginalization and parallel sampling, we reduce computational costs. Our results identify significant eccentricity in GW200105, while other events show low eccentricity. We also highlight challenges in Bayesian inference for eccentric, multi-modal parameter spaces related to sampling and waveform systematics.

Paper Link

arXiv:2508.00179

License and Citation

This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 United States License.

We encourage use of these data products in this work. If you use the materials provided here, kindly acknowledge this work by citing the following reference:

@article{Kacanja:2025kpr,
    author = "Kacanja, Keisi and Soni, Kanchan and Nitz, Alexander Harvey",
    title = "{Eccentricity signatures in LIGO-Virgo-KAGRA's BNS and NSBH binaries}",
    eprint = "2508.00179",
    archivePrefix = "arXiv",
    primaryClass = "gr-qc",
    month = "7",
    year = "2025"
}