{
  "abstract": "We present a multiwavelength study of GRB~260924A at $z=3.51\\pm0.10$ using \\textit{Fermi}, \\textit{Swift}, and ground-based optical and near-infrared observations. Its isotropic-equivalent gamma-ray energy, $E_{γ,\\mathrm{iso}}\\simeq9.79\\times10^{54}$~erg, places it among the most energetic GRBs observed. The prompt emission comprised two bright episodes separated by weaker activity. The X-ray afterglow ranked among the most luminous in our comparison sample at selected post-flare epochs, with a luminosity comparable to that of GRB~221009A at a rest-frame time of 3.5~ks. At a common redshift of $z=1$, the optical afterglow outshone GRB~221009A by approximately 2~mag at 0.3~d and 1~mag near 1~d. LAT emission extended to approximately 1100~s and showed an early excess above the subsequent decay. The highest-energy photon, 43.3~GeV, arrived at 82~s during the first episode; a 14.2~GeV photon arrived at 304~s between episodes. We describe the afterglow light curves through forward-shock synchrotron and synchrotron self-Compton (SSC) emission, with reverse-shock SSC accounting for the early LAT excess. We connect the early and late afterglow phases by modelling the X-ray rebrightening at several kiloseconds through energy injection from trailing ejecta and evolving shock microphysics. The late afterglow suggests a stratified medium, modelled as $n(R)\\propto R^{-1.2}$. Within this interpretation, the magnetic contrast $R_B\\equiv(\\varepsilon_{B,r}/\\varepsilon_{B,f})^{1/2} \\simeq2.6$ suggests magnetized ejecta, while the highest-energy LAT photons exceed the predicted synchrotron limit, supporting an SSC contribution.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.32861",
  "author_total": 7,
  "authors": [
    {
      "name": "Nissim Fraija"
    },
    {
      "name": "Peter Veres"
    },
    {
      "name": "Rosa L. Becerra"
    },
    {
      "name": "Antonio Galván-Gámez"
    },
    {
      "name": "Thomas Freeman"
    },
    {
      "name": "Simone Dichiara"
    },
    {
      "name": "Maria G Dainotti"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/db1czgfqn960q.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.32861",
  "fulltext_url": null,
  "id": "db1czgfqn960q",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.32861",
  "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"
    ],
    [
      "openalex",
      "3103|Gamma-ray bursts and supernovae"
    ]
  ],
  "openalex": "W7223709330",
  "pdf_url": "https://arxiv.org/pdf/2610.32861",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-23",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/db1czgfqn960q.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:15Z",
      "native_id": "2610.32861",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.32861"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "GRB 260924A: Extreme Energetics, Bright GeV Emission, and Exceptional X-ray and Optical Luminosity",
  "title_text": "GRB 260924A: Extreme Energetics, Bright GeV Emission, and Exceptional X-ray and Optical Luminosity",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:15Z",
  "url": "https://research.draconitic.com/paper/db1czgfqn960q",
  "venue": "arXiv",
  "versions": []
}