Skip to content
DraconiticResearch
Search Sources API
201,683 studies31 sourcesUpdated 33 min ago
Peer-reviewedCC BYAstronomy and Astrophysics

Good things always come in 3s: Trimodality in the binary black-hole chirp-mass distribution supports bimodal black-hole formation

  • R. Willcox1,2
  • F. R. N. Schneider3,4
  • E. Laplace5,4,1,2
  • Philipp Podsiadlowski4,6,7
  • Kiril Maltsev8
  • Ilya Mandel9,10
  • Pablo Marchant11
  • Hugues Sana1,2
  • Tjonnie G. F. Li12,13,2
  • Thomas Hertog13,2
13 affiliations
  1. 1Institute of Astronomy, KU Leuven
  2. 2Leuven Gravity Institute, KU Leuven
  3. 3Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg
  4. 4Heidelberger Institut für Theoretische Studien
  5. 5Anton Pannekoek Institute of Astronomy, University of Amsterdam
  6. 6London Centre for Stellar Astrophysics
  7. 7University of Oxford
  8. 8Max-Planck-Institut für Astronomie
  9. 9OzGrav: The ARC Centre of Excellence for Gravitational Wave Discovery
  10. 10School of Physics and Astronomy, Monash University
  11. 11Sterrenkundig Observatorium, Universiteit Gent
  12. 12Department of Electrical Engineering (ESAT), STADIUS, KU Leuven
  13. 13Institute for Theoretical Physics, KU Leuven
Open at sourceDOICite

Abstract

The latest GWTC-5 release from the LIGO–Virgo–KAGRA (LVK) collaboration builds upon the known population of double compact object mergers and reveals new structures in the chirp-mass distribution of merging binary black holes (BBHs). Below 30 M ⊙ , the chirp-mass structure is roughly trimodal, with a sharp drop at ∼10 M ⊙ and a more tentative dip at ∼17 M ⊙ ; we argue that these features are well explained by recent, detailed stellar evolution models, which predict a bimodal distribution in the birth masses of black holes (BHs). This predicted distribution depends only weakly on metallicity and naturally extends to a trimodality in chirp mass, implying universal structural features that can be tested with LVK observations. Using a new compact-remnant mass prescription derived from these models, we performed rapid population synthesis simulations to test the robustness of the predicted chirp-mass structure against uncertainties in binary evolution and cosmic star formation history and compared these simulations with the current observational data. The trimodal chirp-mass distribution emerges as a robust outcome of the new remnant-mass model, persisting across adopted variations in binary and cosmic physics. In contrast, traditional BH formation models lacking a bimodal BH mass spectrum fail to reproduce the observed structure, especially around the sharp drop at ∼10 M ⊙ . Intriguingly, the central chirp-mass peak, dominated by unequal-mass BBHs, originates from a previously underappreciated formation pathway in which strong luminous blue variable winds suppress any binary interaction before the first BH forms. If isolated binary evolution dominates BBH formation below 30 M ⊙ , these universal structure features may provide powerful observational constraints on BH formation, binary evolution, and cosmic star formation, and they may also serve as standard sirens for precision cosmology.

Related

  1. Feedback-Driven Star Formation and YSO Distribution around H II Regions Sh2-140 and Sh2-145
    C Rishi, Neelam Panwar, Ajay Kumar Singh
    arXivPreprintCC BY 4.0Full textGalaxiesarXiv
  2. Halo formation and distribution around cosmic web
    Hongfei Yu, Huiyuan Wang, Yangyao Chen +2
    arXivPreprintarXiv licenceFull textCosmologyarXiv
  3. Spatial distribution of star formation in dwarf galaxies: Merger-driven and secular starburst
    Rakshit Chauhan, Smitha Subramanian
    arXivPreprintCC BY 4.0Full textGalaxiesarXiv
  4. Developing Environments: Formation and Quenching at Cosmic Noon Traced by the Large-scale Distribution of Gas and Galaxies
    Amir H. Khoram, Sirio Belli, Trevor Mendel +15
    arXivPreprintCC BY 4.0Full textGalaxiesarXiv
  5. Bimodal mass primordial black holes in three-field inflation
    M. M. Nasrolahzadeh, N. Khosravi
    arXivPreprintarXiv licenceFull textCosmologyGravitation & general relativityarXiv

Cite

BibTeXRIS
BibTeX
@article{willcox2026good,
  title = {{Good things always come in 3s: Trimodality in the binary black-hole chirp-mass distribution supports bimodal black-hole formation}},
  author = {R. Willcox and F. R. N. Schneider and E. Laplace and Philipp Podsiadlowski and Kiril Maltsev and Ilya Mandel and Pablo Marchant and Hugues Sana and Tjonnie G. F. Li and Thomas Hertog},
  journal = {Astronomy and Astrophysics},
  year = {2026},
  month = aug,
  doi = {10.1051/0004-6361/202557611},
  url = {https://doi.org/10.1051/0004-6361/202557611},
  note = {CC BY},
}
RIS
TY  - JOUR
TI  - Good things always come in 3s: Trimodality in the binary black-hole chirp-mass distribution supports bimodal black-hole formation
AU  - R. Willcox
AU  - F. R. N. Schneider
AU  - E. Laplace
AU  - Philipp Podsiadlowski
AU  - Kiril Maltsev
AU  - Ilya Mandel
AU  - Pablo Marchant
AU  - Hugues Sana
AU  - Tjonnie G. F. Li
AU  - Thomas Hertog
PY  - 2026
DA  - 2026/08/28
JO  - Astronomy and Astrophysics
DO  - 10.1051/0004-6361/202557611
UR  - https://doi.org/10.1051/0004-6361/202557611
AB  - The latest GWTC-5 release from the LIGO–Virgo–KAGRA (LVK) collaboration builds upon the known population of double compact object mergers and reveals new structures in the chirp-mass distribution of merging binary black holes (BBHs). Below 30 M ⊙ , the chirp-mass structure is roughly trimodal, with a sharp drop at ∼10 M ⊙ and a more tentative dip at ∼17 M ⊙ ; we argue that these features are well explained by recent, detailed stellar evolution models, which predict a bimodal distribution in the birth masses of black holes (BHs). This predicted distribution depends only weakly on metallicity and naturally extends to a trimodality in chirp mass, implying universal structural features that can be tested with LVK observations. Using a new compact-remnant mass prescription derived from these models, we performed rapid population synthesis simulations to test the robustness of the predicted chirp-mass structure against uncertainties in binary evolution and cosmic star formation history and compared these simulations with the current observational data. The trimodal chirp-mass distribution emerges as a robust outcome of the new remnant-mass model, persisting across adopted variations in binary and cosmic physics. In contrast, traditional BH formation models lacking a bimodal BH mass spectrum fail to reproduce the observed structure, especially around the sharp drop at ∼10 M ⊙ . Intriguingly, the central chirp-mass peak, dominated by unequal-mass BBHs, originates from a previously underappreciated formation pathway in which strong luminous blue variable winds suppress any binary interaction before the first BH forms. If isolated binary evolution dominates BBH formation below 30 M ⊙ , these universal structure features may provide powerful observational constraints on BH formation, binary evolution, and cosmic star formation, and they may also serve as standard sirens for precision cosmology.
SN  - 0004-6361
SN  - 1432-0746
ER  -