{
  "abstract": "EP241021a is a peculiar fast X-ray transient exhibiting a long X-ray plateau and an optical rebrightening, both challenging the traditional jet afterglow model. Whether its nature is a stellar explosion or a tidal disruption event (TDE) remains debated. Here we present late-time HST/WFC3 and Gemini-N/GMOS observations of its host galaxy at $z=0.748$. After $\\sim300$ days post-trigger, the transient emission had faded below detection, revealing a dwarf disk galaxy with an effective radius $R_e=1.7$ kpc, a stellar mass $M_\\star\\sim3\\times10^8M_\\odot$, and a high star formation rate of $\\sim5\\ M_\\odot\\ {\\rm yr}^{-1}$. Combined with previous very long baseline interferometry measurements, the transient can be located in the galactic disk with a projected physical offset of $0.95\\pm0.13$ kpc from the galaxy center. Host-subtracted optical light curves show that the rebrightening ceased at $\\sim47$ days, followed by a sudden drop with a power-law index steeper than $-3.3$, coincident with a similar drop in the X-ray light curve. This synchronous drop in both bands is consistent with jet shut-off, and the required month-long jet activity suggests a persistently accreting compact object fed by a TDE. Among the TDE scenarios, the off-nuclear location and the starburst host galaxy slightly favor the post-supernova micro-TDE scenario in a binary system, in which a natal kick drives the newborn compact object into a tidal disruption of its companion. Nevertheless, an off-nuclear intermediate-mass black hole TDE or a stellar-mass black hole TDE induced by dynamical scattering in a dense stellar cluster cannot yet be excluded.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.34217",
  "author_total": 20,
  "authors": [
    {
      "name": "Luming Sun"
    },
    {
      "name": "Xinwen Shu"
    },
    {
      "name": "Jiazheng Zhu"
    },
    {
      "name": "Ning Jiang"
    },
    {
      "name": "Bing Zhang"
    },
    {
      "name": "Jin-Hong Chen"
    },
    {
      "name": "Lixin Dai"
    },
    {
      "name": "Hucheng Ding"
    },
    {
      "name": "Chichuan Jin"
    },
    {
      "name": "Wenbin Lu"
    },
    {
      "name": "Rong-Feng Shen"
    },
    {
      "name": "Fan Xu"
    },
    {
      "name": "Lei Yang"
    },
    {
      "name": "Yunwei Yu"
    },
    {
      "name": "Weimin Yuan"
    },
    {
      "name": "Dongyue Li"
    },
    {
      "name": "Dong Xu"
    },
    {
      "name": "Tinggui Wang"
    },
    {
      "name": "Haonan Yang"
    },
    {
      "name": "Wenda Zhang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/af7w4revz7bet.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.34217",
  "fulltext_url": null,
  "id": "af7w4revz7bet",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.34217",
  "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.GA"
    ],
    [
      "arxiv",
      "astro-ph.HE"
    ],
    [
      "openalex",
      "3103|Gamma-ray bursts and supernovae"
    ]
  ],
  "openalex": "W7223803647",
  "pdf_url": "https://arxiv.org/pdf/2610.34217",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-25",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/af7w4revz7bet.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:35Z",
      "native_id": "2610.34217",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.34217"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "EP241021a as An Off-nuclear Month-duration Transient in a Dwarf Starburst Galaxy",
  "title_text": "EP241021a as An Off-nuclear Month-duration Transient in a Dwarf Starburst Galaxy",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:35Z",
  "url": "https://research.draconitic.com/paper/af7w4revz7bet",
  "venue": "arXiv",
  "versions": []
}