{
  "abstract": "In low-metallicity environments, reduced dust abundance weakens molecular cloud shielding against far-ultraviolet radiation, enhancing CO photodissociation and producing extended CO-faint or CO-dark molecular gas. The [CII] 158 $μ$m line is a key tracer of these CO-faint phases. We characterize the multiphase origin of [CII] emission and quantify the CO-faint molecular gas fraction across several regions of the Small Magellanic Cloud (SMC), the nearest low-metallicity ($\\sim 0.2 Z_\\odot$) galaxy. We combine high spectral resolution SOFIA/GREAT and upGREAT [CII], APEX CO(2-1), and ASKAP+Parkes H I 21 cm data to decompose [CII] into its atomic and molecular contributions. On average, $(78\\pm 1)\\%$ of [CII] intensity originates from molecular gas and $(18\\pm 1)\\%$ from atomic gas. The [CII]-traced H$_2$ accounts for $(77\\pm4)\\%$ of the total molecular gas column density, indicating that the SMC molecular reservoir is dominated by CO-faint gas. We derive a H$_2$-to-CO conversion factor $X_{CO}\\approx 8.9\\times10^{20}$ cm$^{-2}$ (K km s$^{-1}$)$^{-1}$ on 4 pc scales in CO-emitting regions, 4.5 times the canonical Galactic value. We find no significant correlation between the CO-dark fraction and either total column density or $Σ_{SFR}$, suggesting that the CO-faint fraction is primarily governed by dust and gas shielding rather than current star formation activity. Our results demonstrate that [CII] is the dominant tracer of molecular gas in the SMC and confirm the prevalence of an extended, stable CO-faint molecular phase in low-metallicity environments.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.05680",
  "author_total": 9,
  "authors": [
    {
      "name": "K. Rodriguez-Ambler"
    },
    {
      "name": "R. Herrera-Camus"
    },
    {
      "name": "M. Rúbio"
    },
    {
      "name": "A. D. Bolatto"
    },
    {
      "name": "D. Riquelme-Vásquez"
    },
    {
      "name": "K. Jameson"
    },
    {
      "name": "C. Muñoz-López"
    },
    {
      "name": "E. J. Tarantino"
    },
    {
      "name": "J. Stutzki"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4vtzfj0c88b5v.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.05680",
  "fulltext_url": null,
  "id": "4vtzfj0c88b5v",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.05680",
  "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/2609.05680",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4vtzfj0c88b5v.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:48Z",
      "native_id": "2609.05680",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.05680"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Tracing the Hidden Molecular Gas in the Small Magellanic Cloud with SOFIA and APEX",
  "title_text": "Tracing the Hidden Molecular Gas in the Small Magellanic Cloud with SOFIA and APEX",
  "type": "preprint",
  "updated_at": "2026-10-30T12:19:48Z",
  "url": "https://research.draconitic.com/paper/4vtzfj0c88b5v",
  "venue": "arXiv",
  "versions": []
}