GW231123 Formation from Population III Stars: Isolated Binary Evolution
4 affiliations
- 1Fukui Prefectural University
- 2Zhaoqing University
- 3Sun Yat-sen University
- 4The University of Tokyo
Abstract
GW231123 is a merger of two black holes (BHs) with estimated masses exceeding 100 M ⊙ , making them the most massive BHs discovered to date via gravitational-wave (GW) observations. We investigate whether GW231123-like events can originate from isolated Population (Pop) III binary stars using binary population synthesis calculations. Our findings indicate that isolated Pop III binaries can produce GW231123-like events at a rate sufficient to explain the discovery of GW231123, provided that three conditions are met: (i) Pop III stars evolve with inefficient convective overshooting, (ii) the 12 C( α , γ ) 16 O rate is 2 σ lower than the standard value, and (iii) Pop III binary stars share the same orbital parameters as Pop I/II binary stars at the initial time. In contrast, GW190521—the most massive BH merger in the Gravitational Wave Transient Catalog 3—can be formed from isolated Pop III binaries even with the standard 12 C( α , γ ) 16 O rate. We demonstrate that the discovery of GW231123 is increasingly constraining the parameter ranges of single-star evolution models, under the assumption that these GW events originate from isolated binary evolution.
Related
- The Mass-Ratio Distribution of the Low-Mass Binary Black Hole Subpopulation: A Natural Outcome of Isolated Binary Evolution
- Evolution of Massive Main-Sequence Stars in Binary Population Synthesis. II. Consequences for Black Hole High-Mass X-ray Binaries and Binary Black Holes
- Eccentricity in Disguise? Insights from GW231123 and Numerically Simulated Binary Black Hole Merger Signals
- The First Model-independent Upper Bound on Microlensing Signature of the Highest-mass Binary Black Hole Event GW231123
- Eccentricity in disguise? Insights from GW231123 and numerically simulated binary black hole merger signals
BibTeX
@article{tanikawa2026gw231123,
title = {{GW231123 Formation from Population III Stars: Isolated Binary Evolution}},
author = {Ataru Tanikawa and Shuai 帅 Liu 刘 and Weiwei Wu and Michiko S. Fujii and Long Wang},
journal = {The Astrophysical Journal},
year = {2026},
month = may,
doi = {10.3847/1538-4357/ae62f5},
url = {https://doi.org/10.3847/1538-4357/ae62f5},
note = {CC BY},
}
RIS
TY - JOUR
TI - GW231123 Formation from Population III Stars: Isolated Binary Evolution
AU - Ataru Tanikawa
AU - Shuai 帅 Liu 刘
AU - Weiwei Wu
AU - Michiko S. Fujii
AU - Long Wang
PY - 2026
DA - 2026/05/15
JO - The Astrophysical Journal
DO - 10.3847/1538-4357/ae62f5
UR - https://doi.org/10.3847/1538-4357/ae62f5
AB - GW231123 is a merger of two black holes (BHs) with estimated masses exceeding 100 M ⊙ , making them the most massive BHs discovered to date via gravitational-wave (GW) observations. We investigate whether GW231123-like events can originate from isolated Population (Pop) III binary stars using binary population synthesis calculations. Our findings indicate that isolated Pop III binaries can produce GW231123-like events at a rate sufficient to explain the discovery of GW231123, provided that three conditions are met: (i) Pop III stars evolve with inefficient convective overshooting, (ii) the 12 C( α , γ ) 16 O rate is 2 σ lower than the standard value, and (iii) Pop III binary stars share the same orbital parameters as Pop I/II binary stars at the initial time. In contrast, GW190521—the most massive BH merger in the Gravitational Wave Transient Catalog 3—can be formed from isolated Pop III binaries even with the standard 12 C( α , γ ) 16 O rate. We demonstrate that the discovery of GW231123 is increasingly constraining the parameter ranges of single-star evolution models, under the assumption that these GW events originate from isolated binary evolution.
SN - 0004-637X
SN - 1538-4357
ER -