{
  "abstract": "Odd radio circles (ORCs) are a recently recognized class of faint, roughly circular diffuse radio sources, typically a few hundred kiloparsecs across, whose origin is still debated. We report the serendipitous discovery of a giant ORC, ORC~J1928$-$5056, in 856~MHz continuum data from the ASKAP observations. The emission forms a single, mildly elliptical structure $4^{\\prime}$ across, corresponding to $0.63$~Mpc at the redshift $z=0.1507$ of the central galaxy LEDA~140850, the brightest cluster galaxy of Abell~3639, which makes it one of the largest single ORCs known. After subtracting the radio nucleus associated with the host galaxy, the ORC has a flux density of 73~mJy integrated within an area of $\\sim 12$~arcmin$^2$, i.e.\\ a mean surface brightness of only $1.7$~$μ$Jy~arcsec$^{-2}$, and a rest-frame luminosity of $L_{1.4}=2\\times10^{24}$~W~Hz$^{-1}$, comparable to those of the most luminous ORCs. Including its nucleus, the system reaches $L_{1.4}=6.6\\times10^{24}$~W~Hz$^{-1}$, higher than that of any other ORC reported so far. The host is a massive ($M_{\\ast}\\sim10^{11}\\,M_{\\odot}$), passive elliptical galaxy with negligible star formation. It contains an AGN jet with a power-law spectrum of index $α=-0.877\\pm0.089$ between 856 and 1656~MHz. Finally, we discuss the implications for ORC formation models and the observations needed to establish the nature of this system.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.36512",
  "author_total": 2,
  "authors": [
    {
      "name": "Renzhi Su"
    },
    {
      "name": "Minfeng Gu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2004cqb7xs2ar.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.36512",
  "fulltext_url": null,
  "id": "2004cqb7xs2ar",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.36512",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "astro-ph.GA"
    ],
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7224107423",
  "pdf_url": "https://arxiv.org/pdf/2610.36512",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-27",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/2004cqb7xs2ar.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:35:50Z",
      "native_id": "2610.36512",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.36512"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "ASKAP Discovery of a Giant Odd Radio Circle at $z=0.15$",
  "title_text": "ASKAP Discovery of a Giant Odd Radio Circle at z=0.15",
  "type": "preprint",
  "updated_at": "2026-10-30T12:35:50Z",
  "url": "https://research.draconitic.com/paper/2004cqb7xs2ar",
  "venue": "arXiv",
  "versions": []
}