{
  "abstract": "We present an X-ray spectro-polarimetric study of the nearby type-1 active galactic nucleus NGC 4151 using two long IXPE observations obtained in 2022 and 2024, supported by simultaneous XMM-Newton and NuSTAR spectroscopy. IXPE measures a polarization degree of $\\sim 6-7\\%$ above 4 keV, with a polarization angle parallel to the radio jet, and a distinct low-energy component with a different angle, indicating at least two polarized components in the $2-8$ keV band. Previous work interpreted the hard X-ray polarization as evidence for a radially extended slab-like corona. Here we test an alternative scenario in which the observed polarization is produced predominantly by relativistic reflection from an accretion disk illuminated by a compact, lamp-post-like corona. Using recently developed models, we fit the IXPE Stokes spectra with a lamp-post plus distant-torus geometry, including partial-covering absorption and an additional soft polarized power-law component. We find that the data require a low coronal height ($h<9\\,R_{\\rm g}$ at $3σ$) and a relatively large torus opening angle ($>45^\\circ$ at 3$σ$), while the disk reflection contributes $\\sim 20\\%$ of the 2-8 keV flux. The soft polarized component carries only $\\sim 1-5\\%$ of the flux but has a high polarization degree ($>10\\%$) and a polarization angle around $20^\\circ$. The same configuration provides acceptable fits to the $0.4-79$ keV XMM-Newton and NuSTAR spectra, demonstrating that disk reprocessing by a compact corona can simultaneously account for both the polarization and broadband spectral properties of NGC 4151.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: ApJ (2026), 1009, 33",
  "arxiv": "2606.08862",
  "author_total": 9,
  "authors": [
    {
      "name": "E. Kammoun"
    },
    {
      "name": "M. Dovčiak"
    },
    {
      "name": "J. Podgorný"
    },
    {
      "name": "I. E. Papadakis"
    },
    {
      "name": "V. Binas-Valavanis"
    },
    {
      "name": "S. Bianchi"
    },
    {
      "name": "V. E. Gianolli"
    },
    {
      "name": "F. Ursini"
    },
    {
      "name": "J. A. García"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/1epafttvp17qj.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.08862",
  "fulltext_url": null,
  "id": "1epafttvp17qj",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.08862",
  "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.HE"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2606.08862",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-15",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/1epafttvp17qj.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:22:01Z",
      "native_id": "2606.08862",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.08862"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "Disk reflection as the origin of the X-ray polarization of NGC 4151 with IXPE",
  "title_text": "Disk reflection as the origin of the X-ray polarization of NGC 4151 with IXPE",
  "type": "preprint",
  "updated_at": "2026-10-30T12:22:01Z",
  "url": "https://research.draconitic.com/paper/1epafttvp17qj",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.3847/1538-4357/ae9cad",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}