{
  "abstract": "Recent studies have shown that the star formation rate (SFR) correlates tightly and linearly with the mass of gravitationally bound gas, which can be delineated from the power-law tail of the column-density probability distribution function ($N$-PDF) derived from dust emission observations. This relationship holds across four orders of magnitude within the Milky Way--spanning low-mass to high-mass star-forming regions and encompassing the extreme environment of the Central Molecular Zone. Building on this framework, we present a new approach for estimating the mass of gravitationally bound gas in molecular clouds using multi-line CO isotopologue observations. Our sample includes 16 molecular clouds with robust detections in $^{12}$CO, $^{13}$CO, and C$^{18}$O $J$ = 1-0, spanning both massive inner Galaxy clouds and nearby star-forming regions. We find that the $N$-PDFs derived from combined CO isotopologue data recover the characteristic log-normal plus power-law profiles seen in dust-based studies. The mass and spatial distribution of the self-gravitating structures estimated from both dust-based and CO-based methods agree well throughout the sample. This indicates that the CO isotopologue combination can robustly trace the self-gravitating component via the $N$-PDF method and provides a reliable, scalable, and velocity-resolved alternative to dust emission for identifying the star-forming gas in molecular clouds.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2608.12473",
  "author_total": 15,
  "authors": [
    {
      "name": "Linjing Feng"
    },
    {
      "name": "Jingwen Wu"
    },
    {
      "name": "Sihan Jiao"
    },
    {
      "name": "Zhi-Yu Zhang"
    },
    {
      "name": "Junzhi Wang"
    },
    {
      "name": "Chao-Wei Tsai"
    },
    {
      "name": "Di Li"
    },
    {
      "name": "Hauyu Baobab Liu"
    },
    {
      "name": "Yan Sun"
    },
    {
      "name": "Neal J. Evans II"
    },
    {
      "name": "Yuxin Lin"
    },
    {
      "name": "Hao Ruan"
    },
    {
      "name": "Fangyuan Deng"
    },
    {
      "name": "Yuanzhen Xiong"
    },
    {
      "name": "Ruofei Zhang"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e39gwsbfcqatd.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2608.12473",
  "fulltext_url": null,
  "id": "e39gwsbfcqatd",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2608.12473",
  "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.GA"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2608.12473",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-12",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/e39gwsbfcqatd.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:31Z",
      "native_id": "2608.12473",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2608.12473"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Trace the Self-Gravitating Gas Using CO Isotopologues",
  "title_text": "Trace the Self-Gravitating Gas Using CO Isotopologues",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:31Z",
  "url": "https://research.draconitic.com/paper/e39gwsbfcqatd",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.3847/1538-4357/ae9cbb",
      "pid": "9xnnsa698rp5j",
      "relation": "published-as",
      "title": "Trace the Self-gravitating Gas Using CO Isotopologues",
      "venue": "The Astrophysical Journal"
    }
  ]
}