{
  "abstract": "Context. The X-ray emission of active galactic nuclei (AGNs) is commonly interpreted as arising from Comptonisation in a hot corona above the accretion disc. A prominent soft X-ray excess is also observed in many sources and is often explained by a warm Comptonising layer. Aims. We investigate the X-ray-emitting coronae of the luminous radio-quiet quasars PG 1407+265 ($z=0.94$) and RBS 229 ($z=0.334$), testing whether a two-corona scenario consistently describes their broadband spectra. Methods. We combine XMM-Newton EPIC and Optical Monitor data with simultaneous NuSTAR observations and long-term Swift monitoring, and model the spectra using Comptonisation models. Results. Both quasars are X-ray loud relative to the standard $α_{\\rm OX}$-$L_{\\rm UV}$ relation, with PG 1407+265 showing the strongest deviation. Their spectra are well reproduced by a warm, optically thick Comptonising component accounting for the soft excess and a hot corona producing the hard X-ray continuum. Both sources show high-energy cut-offs at approximately 70-80 keV. RBS 229 exhibits moderate reflection and a weak neutral Fe K-alpha line, while no significant reflection features are detected in PG 1407+265. The warm-corona parameters of RBS 229 remain consistent across epochs, whereas PG 1407+265 shows strong variability, including an extreme soft-excess episode extending to approximately 3 keV in the rest frame. Conclusions. These results constrain AGN coronae in the poorly explored high-luminosity regime. The cut-offs are broadly consistent with trends in AGN luminosity and accretion rate and remain below the runaway pair-production limit. The contrasting variability suggests that the warm corona responds to changes in the accretion flow while remaining within a narrow range of physical conditions.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.01265",
  "author_total": 11,
  "authors": [
    {
      "name": "Alessandro Leonardo Lai"
    },
    {
      "name": "Stefano Bianchi"
    },
    {
      "name": "Andrea Marinucci"
    },
    {
      "name": "Enrico Piconcelli"
    },
    {
      "name": "Francesco Ursini"
    },
    {
      "name": "Elena Bertola"
    },
    {
      "name": "Giorgio Lanzuisi"
    },
    {
      "name": "Pierre-Olivier Petrucci"
    },
    {
      "name": "Daniel Stern"
    },
    {
      "name": "Cristian Vignali"
    },
    {
      "name": "Luca Zappacosta"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/07gck2c7qsby5.bib",
  "cited_by": 0,
  "doi": "10.1051/0004-6361/202660733",
  "fulltext_url": null,
  "id": "07gck2c7qsby5",
  "issns": [],
  "landing_url": "https://hal.science/hal-05735434v1",
  "language": "en",
  "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"
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    [
      "hal",
      "0.phys"
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    [
      "hal",
      "1.phys.astr"
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    [
      "openalex",
      "3103|Astrophysical Phenomena and Observations"
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  "openalex": "W7203486196",
  "pdf_url": "https://arxiv.org/pdf/2609.01265",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/07gck2c7qsby5.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:24Z",
      "native_id": "hal-05735434",
      "source": "hal",
      "url": "https://hal.science/hal-05735434v1"
    },
    {
      "first_seen": "2026-10-30T12:18:00Z",
      "native_id": "2609.01265",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.01265"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    },
    {
      "field": "physics",
      "origin": "hal:0.phys",
      "subfield": "general"
    }
  ],
  "title": "AGN X-ray coronae at high luminosity: A broadband study of RBS 229 and PG 1407+265",
  "title_text": "AGN X-ray coronae at high luminosity: A broadband study of RBS 229 and PG 1407+265",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:00Z",
  "url": "https://research.draconitic.com/paper/07gck2c7qsby5",
  "venue": "Astron.Astrophys.",
  "versions": [
    {
      "doi": "10.1051/0004-6361/202660733",
      "pid": "07gck2c7qsby5",
      "relation": "published-as",
      "title": "AGN X-ray coronae at high luminosity: A broadband study of RBS 229 and PG 1407+265",
      "venue": "Astron.Astrophys."
    }
  ]
}