{
  "abstract": "Constraining the size of broad-line region (BLR) close to the accretion disk in active galactic nuclei (AGNs) is key to understand the central engine and evolution of AGN. We propose a new method to constrain the BLR size, based on millimeter to sub-millimeter spectral energy distribution (SED), from which a sub-millimeter excess may be found. Such excess can be used to determine the solid angle of the free-free emission region from BLR, as a region with high electron density and optically thick at sub-millimeter wavelength for free-free continuum. Millimeter to sub-millimeter SED analysis toward the central source S1 in a nearby type II AGN NGC 1068 was done, which gave an upper limit on the solid angle of BLR region as(4.94 +/- 0.61) *10^-6 arcsec^2, corresponding to a radius no more than 0.085 pc. Such a constraint on the BLR size is important for estimating the masses of central supermassive black holes in AGNs.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.20260",
  "author_total": 6,
  "authors": [
    {
      "name": "Qi Guo"
    },
    {
      "name": "Junzhi Wang"
    },
    {
      "name": "Lingrui Lin"
    },
    {
      "name": "Yuqiang Li"
    },
    {
      "name": "Zhi-yu Zhang"
    },
    {
      "name": "Fengyao Zhu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dc7kbmydnbyv2.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.20260",
  "fulltext_url": null,
  "id": "dc7kbmydnbyv2",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.20260",
  "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.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.20260",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dc7kbmydnbyv2.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:30:32Z",
      "native_id": "2610.20260",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.20260"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Constrain the Size of Broad Line Region in NGC 1068 Using Sub-millimeter Excess",
  "title_text": "Constrain the Size of Broad Line Region in NGC 1068 Using Sub-millimeter Excess",
  "type": "preprint",
  "updated_at": "2026-10-30T12:33:28Z",
  "url": "https://research.draconitic.com/paper/dc7kbmydnbyv2",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.1093/mnras/stag1946",
      "pid": "2xc6k4gc25cck",
      "relation": "published-as",
      "title": "Constrain the size of broad-line region in NGC 1068 using submillimetre excess",
      "venue": "Monthly Notices of the Royal Astronomical Society"
    }
  ]
}