The Hierarchical Merger Scenario for GW231123

2025/09/10 by Guo-Peng Li, Li, Guo-Peng, Xi-Long Fan +1 · 3 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics of Galaxies (astro-ph.GA) #FOS: Physical sciences #Gamma-ray bursts and supernovae #General Relativity and Quantum Cosmology (gr-qc) #High Energy Astrophysical Phenomena (astro-ph.HE) #Pulsars and Gravitational Waves Research #Solar and Stellar Astrophysics (astro-ph.SR)

paper · pdf · doi:10.48550/arxiv.2509.08298

openalex publication_date 2025/09/10 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

GW231123 exhibits exceedingly massive components and high spins, which challenges the formation of first-generation (1G) black holes from stellar collapse and implies that this event might originate from hierarchical mergers. Here we show that the 2G+2G merger scenario for GW231123 is favored over a 2G+1G (or 3G+2G) merger, with odds ratios of >O(10³). The primary (secondary) black hole is consistent with merging binary black holes with masses of 75⁺⁷_-7 M_\odot and 66⁺⁴_-10 M_\odot (64⁺⁸_-10 M_\odot and 59⁺⁷_-9 M_\odot; 90% credible intervals), respectively. Our results reveal that the treatment of spin priors from the population level and waveform model choice are decisive in interpreting potential hierarchical gravitational-wave signals.

Citations

• Can "premature collapse" form black holes in the upper and lower mass gaps?
• Very Massive, Rapidly Spinning Binary Black Hole Progenitors through Chemically Homogeneous Evolution -- The Case of GW231123
• The degeneracy between microlensing wave effect and precession in strongly lensed gravitational wave
• Astrophysics informed Gaussian processes for gravitational-wave populations: Evidence for the onset of the pair-instability supernova mass gap
• Prospects for the formation of GW231123 from the AGN channel
• GW231123: a Possible Primordial Black Hole Origin
• Accretion is All You Need: Black Hole Spin Alignment in Merger GW231123 Indicates Accretion Pathway
• Dynamical Black Hole in the accelerating Universe approaching the future singularity -- Possible origin of (super-)massive black holes
• GW231123 Formation from Population III Stars: Isolated Binary Evolution
• GW231123: Binary Black Hole Merger or Cosmic String?
• GW231123: Likely a product of successive mergers from ∼ 10 stellar-mass black holes
• GW231123 Mass Gap Event and the Primordial Black Hole Scenario
• Resolving Black Hole Family Issues Among the Massive Ancestors of Very High-Spin Gravitational-Wave Events Like GW231123
• A Star Cluster Population of High Mass Black Hole Mergers in Gravitational Wave Data
• Population of Merging Compact Binaries Inferred Using Gravitational Waves through GWTC-3
• Evidence for Hierarchical Black Hole Mergers in the Second LIGO–Virgo Gravitational Wave Catalog
• GW190521: A Binary Black Hole Merger with a Total Mass of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mn>150</mml:mn><mml:mtext> </mml:mtext><mml:mtext> </mml:mtext><mml:msub><mml:mrow><mml:mi>M</mml:mi></mml:mrow><mml:mrow><mml:mo stretchy="false">⊙</mml:mo></mml:mrow></mml:msub></mml:mrow></mml:math>
• Array programming with NumPy
• emcee : The MCMC Hammer
• Matplotlib: A 2D Graphics Environment

Cited by

• GW241011 and GW241110: Hints of Hierarchical Mergers from the Merger Entropy Index
• Measuring Eccentricity and Addressing Waveform Systematics in GW231123
• A new group of low-spin 50-70M_\odot Black Holes and the high pair-instability mass cutoff
• Can "premature collapse" form black holes in the upper and lower mass gaps?

Related

• Is GW231123 a hierarchical merger?
• GW231123: Likely a product of successive mergers from ∼ 10 stellar-mass black holes
• GW241011 and GW241110: Hints of Hierarchical Mergers from the Merger Entropy Index
• Resolving Black Hole Family Issues Among the Massive Ancestors of Very High-Spin Gravitational-Wave Events Like GW231123
• Hierarchical Black Hole Mergers in Nuclear Star Clusters: A Combined Dynamical-Secular Channel for GW231123-like Events