{
  "abstract": "GW231123 is a gravitational-wave signal originating from the merger of a black hole binary with total mass $\\sim 250 M_{\\odot}$, the largest ever detected by the LIGO-Virgo-Kagra Collaboration. Remarkably, under standard priors, the system features among the fastest-spinning binary components confidently measured in binary mergers, $ χ_{1,2} \\gtrsim 0.7$ at $90\\%$ one-dimensional credibility, according to the most accurate model employed. As typical binary mergers result in remnants with $χ\\sim 0.7$, such spin values are challenging to obtain even from previous (hierarchical) mergers. These inferred properties rely on waveform models lacking eccentric corrections in the merger-ringdown stage. Here, we show that binaries retaining significant eccentricity up to merger can be misinterpreted as near-extremally spinning when non-circular corrections are neglected. Binary-agnostic ringdown analysis instead provides unbiased estimates of the remnant properties, provided that a robust estimate of the signal peak can be obtained. We re-analyse GW231123 using available eccentric numerical-relativity catalogues, finding that although eccentric templates can provide a good fit to the data, quasi-spherical templates are still favoured. Ringdown analyses confirm a secondary likelihood peak correlated with large eccentricity values, but improved eccentric models will be required to assess the reliability of this interpretation. Finally, analysing GW231123 under population-informed parametric priors confirms the exceptional nature of this event within the current black hole binary population.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: Mon Not R Astron Soc (2026)",
  "arxiv": "2606.15150",
  "author_total": 4,
  "authors": [
    {
      "name": "Koustav Chandra"
    },
    {
      "name": "Johann Fernandes"
    },
    {
      "name": "Akshita Mittal"
    },
    {
      "name": "Gregorio Carullo"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3xhdjjdvvahjd.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.15150",
  "fulltext_url": null,
  "id": "3xhdjjdvvahjd",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.15150",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "arxiv",
      "gr-qc"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2606.15150",
  "pmcid": null,
  "pmid": null,
  "published": "2026-06-13",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3xhdjjdvvahjd.ris",
  "sources": [
    {
      "first_seen": "2026-11-04T15:21:24Z",
      "native_id": "2606.15150",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.15150"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "arxiv:gr-qc",
      "subfield": "gravitation"
    }
  ],
  "title": "Eccentricity in Disguise? Insights from GW231123 and Numerically Simulated Binary Black Hole Merger Signals",
  "title_text": "Eccentricity in Disguise? Insights from GW231123 and Numerically Simulated Binary Black Hole Merger Signals",
  "type": "preprint",
  "updated_at": "2026-11-06T18:21:01Z",
  "url": "https://research.draconitic.com/paper/3xhdjjdvvahjd",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1093/mnras/stag1934",
      "pid": "7gex9a4ecsvs0",
      "relation": "published-as",
      "title": "Eccentricity in disguise? Insights from GW231123 and numerically simulated binary black hole merger signals",
      "venue": "Monthly Notices of the Royal Astronomical Society"
    }
  ]
}