{
  "abstract": "Constraining the size of broad-line region (BLR) close to the accretion disc in active galactic nuclei (AGNs) is key to understand the central engine and evolution of AGNs. We propose a new method to constrain the BLR size, based on millimetre to submillimetre spectral energy distribution (SED), from which a submillimetre 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 submillimetre wavelength for free–free continuum. Millimetre to submillimetre SED analysis towards 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 $(4.94 \\pm 0.61)\\times 10^{-6}\\ {\\rm arcsec}^2$, 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": [
    "Guangxi Key Laboratory for Relativistic Astrophysics, School of Physical Science and Technology, Guangxi University , Nanning 530004 ,",
    "School of Astronomy and Space Science, Nanjing University , Nanjing 210093 ,",
    "Key Laboratory of Modern Astronomy and Astrophysics, Nanjing University, Ministry of Education , Nanjing 210023 ,",
    "INAF–Arcetri Astrophysical Observatory , Large E. Fermi 5, I-50125 Florence ,",
    "Korea Astronomy and Space Science Institute , No. 776, Daedeok-daero, Yuseong-gu, Daejeong 34055 ,",
    "Research Center for Computational Earth and Space Science, Zhejiang Laboratory , Hangzhou 311100 ,"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Qi Guo"
    },
    {
      "affs": [
        0
      ],
      "name": "Junzhi Wang",
      "orcid": "0000-0001-6106-1171"
    },
    {
      "affs": [
        1,
        2,
        3
      ],
      "name": "Lingrui Lin",
      "orcid": "0000-0002-2231-8381"
    },
    {
      "affs": [
        4
      ],
      "name": "Yuqiang Li"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Zhi-yu Zhang",
      "orcid": "0000-0002-7299-2876"
    },
    {
      "affs": [
        5
      ],
      "name": "Fengyao Zhu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/2xc6k4gc25cck.bib",
  "cited_by": 0,
  "doi": "10.1093/mnras/stag1946",
  "fulltext_url": null,
  "id": "2xc6k4gc25cck",
  "issns": [
    "0035-8711",
    "1365-2966"
  ],
  "landing_url": "https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1946/8914587",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7221681964",
  "pdf_url": "https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stag1946/71915176/stag1946.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-13",
  "publisher": "Oxford University Press (OUP)",
  "ris": "https://research.draconitic.com/paper/2xc6k4gc25cck.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:17Z",
      "native_id": "10.1093/mnras/stag1946",
      "source": "crossref",
      "url": "https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1946/8914587"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Galaxies: Formation, Evolution, Phenomena",
      "subfield": "galaxies"
    }
  ],
  "title": "Constrain the size of broad-line region in NGC 1068 using submillimetre excess",
  "title_text": "Constrain the size of broad-line region in NGC 1068 using submillimetre excess",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:17Z",
  "url": "https://research.draconitic.com/paper/2xc6k4gc25cck",
  "venue": "Monthly Notices of the Royal Astronomical Society",
  "versions": [
    {
      "doi": "10.48550/arxiv.2610.20260",
      "pid": "dc7kbmydnbyv2",
      "relation": "preprint",
      "title": "Constrain the Size of Broad Line Region in NGC 1068 Using Sub-millimeter Excess",
      "venue": "arXiv"
    }
  ]
}