{
  "abstract": "GW231123 is the most massive binary black hole merger observed to date and one of the most intriguing hierarchical merger candidates in the pair-instability mass gap. Its exceptionally large inferred component spins and remarkably short in-band duration make the source highly sensitive to waveform physics near merger. Here we show that GW231123 is better described as an eccentric binary black-hole merger. We analyse data over 11--448 Hz using the eccentric, spin-precessing effective-one-body waveform model TEOBResumS--Dalí, accounting for detector calibration uncertainty. We measure $e_{5.5\\,\\mathrm{Hz}}=0.34^{+0.12}_{-0.23}$ at 90\\% credibility and obtain a Bayes factor of 10.2 in favour of the eccentric model over its quasi-circular counterpart. GW231123-like injection--recovery studies further show that analyses starting at 20 Hz, as in previous studies, can obscure this eccentricity. Including eccentricity substantially changes the spin inference, weakening the preference for a near-extremal secondary spin and lowering its posterior median to $a_2\\simeq0.7$, close to the characteristic spin expected for a black-hole merger remnant. These results provide a coherent dynamical interpretation of GW231123, in which residual eccentricity, a mass-gap black hole, and a remnant-like spin arise naturally from a hierarchical merger channel in a dense environment.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.12205",
  "author_total": 6,
  "authors": [
    {
      "name": "Baoxiang Wang"
    },
    {
      "name": "Tao Yang"
    },
    {
      "name": "Zhoujian Cao"
    },
    {
      "name": "Bin Hu"
    },
    {
      "name": "Xikai Shan"
    },
    {
      "name": "Rong-Gen Cai"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4707qg238qfcv.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.12205",
  "fulltext_url": null,
  "id": "4707qg238qfcv",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.12205",
  "language": null,
  "licence": "LicenseRef-arXiv-nonexclusive-1.0",
  "licence_label": "arXiv licence",
  "licence_source": "article",
  "licence_url": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "arxiv",
      "gr-qc"
    ],
    [
      "openalex",
      "3103|Pulsars and Gravitational Waves Research"
    ]
  ],
  "openalex": "W7221109581",
  "pdf_url": "https://arxiv.org/pdf/2610.12205",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-08",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4707qg238qfcv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:27:54Z",
      "native_id": "2610.12205",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.12205"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Evidence for orbital eccentricity supports a hierarchical origin for GW231123",
  "title_text": "Evidence for orbital eccentricity supports a hierarchical origin for GW231123",
  "type": "preprint",
  "updated_at": "2026-10-30T12:27:54Z",
  "url": "https://research.draconitic.com/paper/4707qg238qfcv",
  "venue": "arXiv",
  "versions": []
}