{
  "abstract": "GRB 251222A is a long-duration gamma-ray burst at a spectroscopic redshift of $z=3.171$. It was detected by the EP as the soft X-ray transient EP251222b before and during the gamma-ray emission. We performed a multi-wavelength (EP/WXT, fermi/GBM, swift/XRT and optical/NIR) investigation of this event. Its prompt soft X-ray and gamma-ray features, together with two afterglow rebrightenings, allow us to examine a possible connection between the prompt ejecta and the afterglow. We consider a multiple-shell scenario in which a faster, narrower shell catches up with a slower, wider shell. We assume that the selected pulse groups trace different ejecta and that the late X-ray flare marks their collision. Under these assumptions, we represent the post-collision outflow by an effective merged core and an outer annular component. A joint fit to the multi-band afterglow gives a Lorentz factor of $Γ_c\\approx293$ for the merged core and $Γ_{1,w}\\approx228$ for the outer component. The sample-wise collision mapping gives an energy release of $E_{\\rm diss}=(1.6^{+2.1}_{-0.9})\\times10^{52}$ erg and a dynamical dissipation efficiency of $0.37^{+0.07}_{-0.14}\\%$. EP251222b can therefore be used to test a prompt--afterglow connection through shell collisions, although it does not uniquely establish this interpretation.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.21583",
  "author_total": 26,
  "authors": [
    {
      "name": "Run Shi"
    },
    {
      "name": "Di Xiao"
    },
    {
      "name": "Brajesh Kumar"
    },
    {
      "name": "Yifang Liang"
    },
    {
      "name": "Guowang Du"
    },
    {
      "name": "Jinjun Geng"
    },
    {
      "name": "Wenlong Zhang"
    },
    {
      "name": "Yuan Fang"
    },
    {
      "name": "Chenlei Guo"
    },
    {
      "name": "Dingfang Hu"
    },
    {
      "name": "Jie Hu"
    },
    {
      "name": "Qiuju Huang"
    },
    {
      "name": "Yanlong Hua"
    },
    {
      "name": "Yongfeng Huang"
    },
    {
      "name": "HongGuang Li"
    },
    {
      "name": "Xiangkun Liu"
    },
    {
      "name": "Xiaowei Liu"
    },
    {
      "name": "Yuan Liu"
    },
    {
      "name": "Jirong Mao"
    },
    {
      "name": "Xuan Mao"
    },
    {
      "name": "Bao Wang"
    },
    {
      "name": "Yuanpei Yang"
    },
    {
      "name": "Shiyan Zhong"
    },
    {
      "name": "Dan Zhu"
    },
    {
      "name": "Xuefeng Wu"
    },
    {
      "name": "Weimin Yuan"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dn0b65ehrmjqn.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.21583",
  "fulltext_url": null,
  "id": "dn0b65ehrmjqn",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.21583",
  "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",
      "3103|Gamma-ray bursts and supernovae"
    ]
  ],
  "openalex": "W7222461819",
  "pdf_url": "https://arxiv.org/pdf/2610.21583",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dn0b65ehrmjqn.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:50Z",
      "native_id": "2610.21583",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.21583"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "A Shell Collision Scenario for EP251222b/GRB 251222A: Connecting Prompt Emission and Double-Peaked Afterglow",
  "title_text": "A Shell Collision Scenario for EP251222b/GRB 251222A: Connecting Prompt Emission and Double-Peaked Afterglow",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:50Z",
  "url": "https://research.draconitic.com/paper/dn0b65ehrmjqn",
  "venue": "arXiv",
  "versions": []
}