Defining eccentricity for spin-precessing binaries
Creators
-
1.
Vidyasagar University
-
2.
Seoul National University
-
3.
University of Massachusetts Dartmouth
-
4.
University of the Balearic Islands
-
5.
Max Planck Institute for Gravitational Physics
-
6.
Cornell University
-
7.
California Institute of Technology
Abstract
Standardizing the definition of eccentricity is necessary for unambiguous inference of the orbital eccentricity of compact binaries from gravitational wave observations. In previous works, we proposed a definition of eccentricity for systems without spin-precession that relies solely on the gravitational waveform, is applicable to any waveform model, and has the correct Newtonian limit. In this work, we extend this definition to spin-precessing systems. This simple yet effective extension relies on first transforming the waveform from the inertial frame to the coprecessing frame, and then adopting an amplitude and a phase with reduced spin-induced effects. Our method includes a robust procedure for filtering out spin-induced modulations, which become non-negligible in the small eccentricity and large spin-precession regime. Finally, we apply our method to a set of Numerical Relativity and Effective One Body waveforms to showcase its robustness for generic eccentric spin-precessing binaries. We make our method public via Python implementation in gw_eccentricity.
Copyright and License
© 2025 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
Acknowledgement
The authors thank Keefe Mitman, Rossella Gamba for valuable comments on the draft, and Aldo Gamboa and Leo C Stein for useful discussion. M A S’s research was partially supported by the National Research Foundation of Korea under Grant No. NRF-2021R1A2C2012473. V V acknowledges support from National Science Foundation (NSF) Grant No. PHY-2309301 and UMass Dartmouth’s Marine and Undersea Technology (MUST) Research Program funded by the Office of Naval Research (ONR) under Grant No. N00014-23-1-2141. A Ramos-Buades is supported by the Veni research programme which is (partly) financed by the Dutch Research Council (NWO) under the Grant VI.Veni.222.396; acknowledges support from the Spanish Agencia Estatal de Investigación Grant PID2022-138626NB-I00 funded by MICIU/AEI/10.13039/501100011033 and the ERDF/EU; is supported by the Spanish Ministerio de Ciencia, Innovación y Universidades (Beatriz Galindo, BG23/00056) and co-financed by Universitat de les Illes Balears. L E Kidder’s work was supported by the NSF under Grants Nos. PHY-2407742, PHY- 2207342, and OAC-2209655, and by the Sherman Fairchild Foundation at Cornell. This material is based upon work supported by NSF’s LIGO Laboratory which is a major facility fully funded by the NSF. Part of the numerical calculations reported in this paper, as well as the development of gw_eccentricity [90], were carried out on the Alice cluster at the International Centre for Theoretical Sciences, Tata Institute of Fundamental Research.
Data Availability
The data cannot be made publicly available upon publication because the cost of preparing, depositing and hosting the data would be prohibitive within the terms of this research project. The data that support the findings of this study are available upon reasonable request from the authors.
Additional details
Related works
- Is new version of
- Discussion Paper: arXiv:2507.08345 (arXiv)
Funding
- National Research Foundation of Korea
- NRF-2021R1A2C2012473
- National Science Foundation
- PHY-2309301
- Office of Naval Research
- N00014-23-1-2141
- Dutch Research Council
- VI.Veni.222.396
- Agencia Estatal de Investigación
- PID2022-138626NB-I00
- Ministerio de Ciencia, Innovación y Universidades
- BG23/00056
- Universitat de les Illes Balears
- National Science Foundation
- PHY-2407742
- National Science Foundation
- PHY- 2207342
- National Science Foundation
- OAC-2209655
- Sherman Fairchild Foundation
Dates
- Accepted
-
2025-09-17
- Available
-
2025-09-29Published