{
  "abstract": "The star formation efficiency per free-fall time ($ε_{\\rm ff}$) quantifies how efficiently giant molecular clouds (GMCs) convert gas into stars and is often observed to be orders of magnitude lower than expected for free-fall collapse. Observers typically estimate $ε_{\\rm ff}$ by mapping far-infrared (FIR) dust emission to infer gas surface densities ($Σ_{\\rm gas}$) and counting embedded protostars, assuming simplified lifetimes and masses. Using the fiducial STARFORGE radiation-magnetohydrodynamics simulation of an $M_{\\rm cl} = 2\\times10^4 M_\\odot$ GMC that self-consistently models star cluster formation and stellar feedback, we generate synthetic FIR observations and apply the same methodologies used in GMC surveys to investigate this discrepancy. We present the first $ε_{\\rm ff}-Σ_{\\rm gas}$ analysis in a fully feedback-regulated GMC simulation that resolves the formation of stellar systems. Our synthetic measurements reproduce the low observationally inferred efficiencies, showing that feedback-regulated star formation naturally produces $ε_{\\rm ff} \\sim 1-3\\%$ without requiring extreme initial conditions. We also find that $ε_{\\rm ff}$ varies strongly over a GMC's lifetime, suggesting that much of the observed scatter reflects evolutionary sampling rather than intrinsic cloud-to-cloud differences. Finally, by comparing observational and simulation definitions, we show that methodological assumptions introduce systematic biases, with a transition near $\\log Σ_{\\rm gas} \\approx 2.3 M_\\odot {\\rm pc}^{-2}$ that depends on resolution. Above this threshold, the smoothing of dense structure increases both the inferred free-fall time and enclosed gas, with the latter dominating and suppressing $ε_{\\rm ff}$. Below the threshold, the discrepancies are primarily driven by star formation rate assumptions.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": "Journal reference: ApJ 1004, 14 (2026)",
  "arxiv": "2610.12729",
  "author_total": 3,
  "authors": [
    {
      "name": "Alexander Escamilla"
    },
    {
      "name": "Michael Y. Grudić"
    },
    {
      "name": "Anna L. Rosen"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/3xyf60vv22v2e.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.12729",
  "fulltext_url": null,
  "id": "3xyf60vv22v2e",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.12729",
  "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"
    ],
    [
      "arxiv",
      "astro-ph.SR"
    ]
  ],
  "openalex": null,
  "pdf_url": "https://arxiv.org/pdf/2610.12729",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-08",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/3xyf60vv22v2e.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:28:36Z",
      "native_id": "2610.12729",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.12729"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    },
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.SR",
      "subfield": "stellar"
    }
  ],
  "title": "Bridging Theory and Observation: Synthetic Far-infrared Insights into Star Formation Efficiency",
  "title_text": "Bridging Theory and Observation: Synthetic Far-infrared Insights into Star Formation Efficiency",
  "type": "preprint",
  "updated_at": "2026-10-30T12:28:36Z",
  "url": "https://research.draconitic.com/paper/3xyf60vv22v2e",
  "venue": "arXiv",
  "versions": [
    {
      "doi": "10.3847/1538-4357/ae6cdc",
      "pid": null,
      "relation": "published-as",
      "title": null,
      "venue": null
    }
  ]
}