{
  "abstract": "We present a multi-wavelength study of GRB 260310A, a nearby long-duration gamma-ray burst at $z\\simeq0.153$ associated with a broad-lined Type Ic supernova. Despite its modest prompt gamma-ray output, $E_{γ,\\rm iso}\\simeq3.5\\times10^{50}$ erg, GRB 260310A exhibits one of the brightest afterglows ever observed in the X-ray, optical, and radio bands. Its apparent brightness is not its only remarkable feature. The optical afterglow displays a delayed onset, characterized by a slow rising phase, with slope $α\\approx-1$, and a late peak at $\\approx$0.1 d. We argue that the combination of weak prompt emission, hard peak energy, and late afterglow onset is naturally explained by a GRB jet viewed off-axis. The radio spectral energy distributions are consistent with synchrotron radiation and indicate the presence of both reverse- and forward-shock components, thus providing a first test of reverse-shock models in an off-axis geometry. The X-ray afterglow displays a prominent rebrightening, monitored for up to $\\approx$68 d with no evidence of spectral evolution. A low level of linear polarization, $Π\\approx1.7\\%$, is measured at 15 GHz at $T_0+55$ d and suggests that, at these late times, the forward-shock is the dominant emission component from radio to X-rays. This late-time rebrightening represents a critical test for the two-component jet model. If interpreted as the emergence of a narrow jet core viewed further off-axis, it would imply extreme luminosities and energetics for an on-axis observer.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2605.23818",
  "author_total": 34,
  "authors": [
    {
      "name": "Yu-Han Yang"
    },
    {
      "name": "Roberto Ricci"
    },
    {
      "name": "Eleonora Troja"
    },
    {
      "name": "Muskan Yadav"
    },
    {
      "name": "Yi-Han Iris Yin"
    },
    {
      "name": "Rubén Sánchez-Ramírez"
    },
    {
      "name": "Brendan O'Connor"
    },
    {
      "name": "Niccoló Passaleva"
    },
    {
      "name": "Alberto J. Castro-Tirado"
    },
    {
      "name": "Hendrik van Eerten"
    },
    {
      "name": "Simone Dichiara"
    },
    {
      "name": "Vincenzo Galluzzi"
    },
    {
      "name": "Narjes Shahamat Dehsorkh"
    },
    {
      "name": "Iván Agudo"
    },
    {
      "name": "Jesús Aceituno"
    },
    {
      "name": "Malte Busmann"
    },
    {
      "name": "María D. Caballero-García"
    },
    {
      "name": "Emilio Fernández-García"
    },
    {
      "name": "Daniel Gruen"
    },
    {
      "name": "Maria Gritsevich"
    },
    {
      "name": "Sergiy Guziy"
    },
    {
      "name": "David Hiriart"
    },
    {
      "name": "You-Dong Hu"
    },
    {
      "name": "Martin Jelínek"
    },
    {
      "name": "Alexander Kutyrev"
    },
    {
      "name": "Alzbeta Malenakova"
    },
    {
      "name": "Filip Novotny"
    },
    {
      "name": "Ignacio Pérez-García"
    },
    {
      "name": "Shashi B. Pandey"
    },
    {
      "name": "Jorma Ryske"
    },
    {
      "name": "Alfredo Sota"
    },
    {
      "name": "Jan Strobl"
    },
    {
      "name": "Hira Waseem"
    },
    {
      "name": "Siyu Wu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/22ybrjr44cenn.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2605.23818",
  "fulltext_url": null,
  "id": "22ybrjr44cenn",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2605.23818",
  "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"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2605.23818",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-19",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/22ybrjr44cenn.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:19Z",
      "native_id": "2605.23818",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2605.23818"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "An extremely bright slow-rising afterglow from an off-axis jet in GRB 260310A",
  "title_text": "An extremely bright slow-rising afterglow from an off-axis jet in GRB 260310A",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:19Z",
  "url": "https://research.draconitic.com/paper/22ybrjr44cenn",
  "venue": "arXiv",
  "versions": []
}