On the Astrophysical Origin of Binary Black Hole Subpopulations: A Tale of Three Channels?
4 affiliations
- 1NSF–Simons AI Institute for the Sky (SkAI)
- 2Northwestern University
- 3University of Oklahoma
- 4Adler Planetarium
Abstract
There is increasing evidence for multiple binary black hole (BBH) subpopulations in the cumulative gravitational-wave catalog of the LIGO–Virgo–KAGRA Collaboration. The astrophysical interpretation of this complex underlying population is subject to theoretical uncertainties in treatments of binary stellar evolution, core collapse, and host environments. In this Letter, using parameterized mixture models, we show that the BBH detection sample comprises three astrophysical subpopulations that are likely dominated by specific formation channels. In particular, we show that the 10 M ⊙ peak and the 35 M ⊙ feature in the BBH mass spectrum correspond to distinct mass-ratio, spin alignment, spin precession, and redshift evolution properties. We show that mass-based transitions reported in the distribution of BBH parameters naturally emerge from our inferred distributions without explicit modeling. Our results are consistent with the current observed population arising from specific relative abundances of isolated binary evolution, dynamical formation in globular clusters, and higher-generation BBH mergers. Under this interpretation, we constrain the relative underlying fractions of these channels to be 79 . 0 − 10.9 + 11.5 % , 14 . 5 − 8.0 + 11.6 % , and 2 . 5 − 1.8 + 5.5 % , respectively, and find these relative fractions to be evolving over cosmic time with more than 1 σ confidence. Our interpretation relies on simple theoretical predictions that are mostly robust against uncertainties in BBH formation, with more definite conclusions expected in the near future.
Related
- Compactness Peaks and Subpopulations: Probing Stellar Physics and Formation Channels of Merging Binary Black Holes
- Evidence for Three Subpopulations of Merging Binary Black Holes at Different Primary Masses
- Characterizing Binary Black Hole Subpopulations in GWTC-4 with Binned Gaussian Processes: On the Origins of the 35 M ⊙ Peak
- Three subpopulations of binary black holes in mass, spin magnitudes and tilts following GWTC-5
- Testing Spin Prior Assumptions of Binary Black Hole Parameter Inference and Their Astrophysical Implications
BibTeX
@article{ray2026astrophysical,
title = {{On the Astrophysical Origin of Binary Black Hole Subpopulations: A Tale of Three Channels?}},
author = {Anarya Ray and Subhasis Mukherjee - and M. Zevin and V. Kalogera},
journal = {The Astrophysical Journal Letters},
year = {2026},
month = jul,
doi = {10.3847/2041-8213/ae80cb},
url = {https://doi.org/10.3847/2041-8213/ae80cb},
note = {CC BY},
}
RIS
TY - JOUR
TI - On the Astrophysical Origin of Binary Black Hole Subpopulations: A Tale of Three Channels?
AU - Anarya Ray
AU - Subhasis Mukherjee -
AU - M. Zevin
AU - V. Kalogera
PY - 2026
DA - 2026/07/06
JO - The Astrophysical Journal Letters
DO - 10.3847/2041-8213/ae80cb
UR - https://doi.org/10.3847/2041-8213/ae80cb
AB - There is increasing evidence for multiple binary black hole (BBH) subpopulations in the cumulative gravitational-wave catalog of the LIGO–Virgo–KAGRA Collaboration. The astrophysical interpretation of this complex underlying population is subject to theoretical uncertainties in treatments of binary stellar evolution, core collapse, and host environments. In this Letter, using parameterized mixture models, we show that the BBH detection sample comprises three astrophysical subpopulations that are likely dominated by specific formation channels. In particular, we show that the 10 M ⊙ peak and the 35 M ⊙ feature in the BBH mass spectrum correspond to distinct mass-ratio, spin alignment, spin precession, and redshift evolution properties. We show that mass-based transitions reported in the distribution of BBH parameters naturally emerge from our inferred distributions without explicit modeling. Our results are consistent with the current observed population arising from specific relative abundances of isolated binary evolution, dynamical formation in globular clusters, and higher-generation BBH mergers. Under this interpretation, we constrain the relative underlying fractions of these channels to be 79 . 0 − 10.9 + 11.5 % , 14 . 5 − 8.0 + 11.6 % , and 2 . 5 − 1.8 + 5.5 % , respectively, and find these relative fractions to be evolving over cosmic time with more than 1 σ confidence. Our interpretation relies on simple theoretical predictions that are mostly robust against uncertainties in BBH formation, with more definite conclusions expected in the near future.
SN - 2041-8205
SN - 2041-8213
ER -