{
  "abstract": "Accretion-disc corona sources are high-inclination low-mass X-ray binaries in which the innermost regions are hidden and the observed X-ray emission is dominated by radiation scattered above the disc. 4U 1822-37 is a key binary system of this class, but its geometry is still debated. X-ray polarimetry offers a direct probe of the scattering structure. We present the first X-ray spectro-polarimetric study of 4U 1822-37 and test whether its spectrum and polarisation can be explained within the accretion-disc-corona scenario. We analysed a coordinated campaign with IXPE, XMM-Newton, NuSTAR, and Swift. We performed broadband spectral modelling and model-independent, energy-resolved, and orbital-phase-resolved polarimetric analyses. The broadband spectrum requires a soft thermal component, a Comptonised continuum, a hard power-law tail, and relativistically blurred reflection. The observed 0.1-100 keV luminosity, $L_{\\rm obs}\\simeq6.1\\times10^{36}\\ {\\rm erg\\,s^{-1}}$, is far below the intrinsic luminosity expected from the orbital evolution, supporting a geometry in which only a small fraction of the intrinsic emission is scattered into the line of sight by an extended, optically thin corona. In the 2-8 keV band, IXPE measures ${\\rm PD}=7.9\\pm0.6\\%$ and ${\\rm PA}=-24^\\circ\\pm2^\\circ$. The PD increases with energy, while the PA remains approximately constant. During eclipse, the PD decreases to ${\\rm PD}=5.5\\pm1.7\\%$, with no significant PA variation. This behaviour is consistent with the companion occulting the most polarimetrically efficient part of the extended corona. The high PD, stable PA, energy-dependent polarisation, and eclipse behaviour support a picture in which 4U 1822-37 is observed in an extreme high-inclination, scattering-dominated regime. The extended corona is the main structure shaping both the observed X-ray emission and its polarisation.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2605.19877",
  "author_total": 19,
  "authors": [
    {
      "name": "A. Anitra"
    },
    {
      "name": "A. Gnarini"
    },
    {
      "name": "T. Di Salvo"
    },
    {
      "name": "R. Iaria"
    },
    {
      "name": "A. Marino"
    },
    {
      "name": "F. Barra"
    },
    {
      "name": "L. Burderi"
    },
    {
      "name": "A. Sanna"
    },
    {
      "name": "L. Marra"
    },
    {
      "name": "S. Bianchi"
    },
    {
      "name": "G. Matt"
    },
    {
      "name": "F. Ursini"
    },
    {
      "name": "C. Miceli"
    },
    {
      "name": "A. Miraval Zanon"
    },
    {
      "name": "W. Leone."
    },
    {
      "name": "F. Capitanio"
    },
    {
      "name": "S. Fabiani"
    },
    {
      "name": "P. Kaaret"
    },
    {
      "name": "A. Tarana"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/d0csbd99zpe48.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2605.19877",
  "fulltext_url": null,
  "id": "d0csbd99zpe48",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2605.19877",
  "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/2605.19877",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-24",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/d0csbd99zpe48.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:24:11Z",
      "native_id": "2605.19877",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2605.19877"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "The first IXPE view of the eclipsing ADC source 4U 1822-37",
  "title_text": "The first IXPE view of the eclipsing ADC source 4U 1822-37",
  "type": "preprint",
  "updated_at": "2026-10-30T12:24:11Z",
  "url": "https://research.draconitic.com/paper/d0csbd99zpe48",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1051/0004-6361/202661002",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}