{
  "abstract": "We investigate the long-term X-ray spectral evolution of the highly luminous, radio-quiet quasar PDS 456 using AstroSat observations obtained in 2019 and 2021 together with archival XMM-Newton, NuSTAR and Suzaku observations spanning 2001-2024. The AstroSat observations provide valuable coverage following the bright flaring state observed in 2018, revealing that the source underwent a relatively quiescent phase in 2019 before re-brightening in 2021. During the AstroSat epochs, PDS 456 exhibits a harder-when-brighter spectral trend, whereas the long-term XMM-Newton, NuSTAR, and Suzaku observations confirm the overall softer-when-fainter behavior. This behavior is consistent with the presence of a very cool corona (~15 keV), possibly driven by a strong incident photon field for upscattering, as suggested by a prominent big blue bump. Broadband spectral modeling of simultaneous XMM-Newton and NuSTAR observations, complemented by the 2021 AstroSat flaring epoch and interpreted within the self-consistent physical framework reXcor, indicates that the disk-corona energy balance evolves with flux. In low-flux states, the spectrum is reflection-dominated, implying efficient illumination of the inner accretion disk by a compact corona. In contrast, high-flux states show an enhanced contribution from the warm Comptonizing region at larger coronal heights. The Fe Kα emission line displays a positive correlation with the 2-10 keV continuum flux at low to intermediate flux levels, while deviations at the highest flux states suggest a reduced relative reflection contribution as the warm corona becomes energetically dominant.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.41509",
  "author_total": 4,
  "authors": [
    {
      "name": "Fida Fathima S S"
    },
    {
      "name": "Arijit Sar"
    },
    {
      "name": "Tathagata Saha"
    },
    {
      "name": "Ritaban Chatterjee"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bh837dd78x9b3.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.41509",
  "fulltext_url": null,
  "id": "bh837dd78x9b3",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.41509",
  "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/2610.41509",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-30",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/bh837dd78x9b3.ris",
  "sources": [
    {
      "first_seen": "2026-11-02T12:21:15Z",
      "native_id": "2610.41509",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.41509"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.HE",
      "subfield": "high-energy-astrophysics"
    }
  ],
  "title": "Disk-Corona Energy Balance Evolves with Flux State in the Quasar PDS 456",
  "title_text": "Disk-Corona Energy Balance Evolves with Flux State in the Quasar PDS 456",
  "type": "preprint",
  "updated_at": "2026-11-04T15:20:51Z",
  "url": "https://research.draconitic.com/paper/bh837dd78x9b3",
  "venue": "arXiv",
  "versions": []
}