{
  "abstract": "One of the fundamental uncertainties in the study of galaxies at the interface between star formation and quiescence--post-starburst galaxies--is their instantaneous star formation rate. While these galaxies appear quiescent in the rest UV-optical, many of the youngest systems are highly CO luminous, implying dense molecular gas, and potentially star formation. However, their instantaneous star formation rates have proved elusive, as measurements with rest-optical emission lines or UV-to-IR SED fitting yield order-of-magnitude uncertainty. Here, we present JWST/NIRSpec G395M/170LP integral field spectroscopy of the three most CO-luminous massive galaxies in the SQuIGG$\\vec{L}$E survey, spatially resolving Pa$α$/Br$γ$/Br$β$ to map the dust-corrected star formation rate. We find that these galaxies host star formation rates of $27-80$ $M_\\odot \\ \\mathrm{yr^{-1}}$, though $\\sim30-40\\%$ of the emission may arise from non-star-forming ionization (AGN or shocks), implied by high [FeII]/Pa$α$ in central spaxels. We also find effective $A_{\\mathrm{Pa}α}\\sim1$ and individual $\\sim700$ pc spaxels with $A_{\\mathrm{Paα}}\\sim2$, implying significant dust obscuration of nebular regions that contribute little to the rest-optical lines. These galaxies are not consistent with total quiescence; the measured star formation rates place these galaxies on or above the main sequence. However, their star formation rates \\textit{are} significantly lower ($\\sim0.5-1$ dex) than the peak star formation rates inferred from spectrophotometric fitting. We propose that the CO luminous post-starburst phase represents the last gasp of star formation in galaxies on the rapid quenching pathway, and that dust-obscured star formation, outflows, and (speculatively) an uncertain CO-to-H2 conversion reconcile their gas exhaustion with observed timescales of fading.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.31307",
  "author_total": 16,
  "authors": [
    {
      "name": "David J. Setton"
    },
    {
      "name": "Jenny E. Greene"
    },
    {
      "name": "Rachel Bezanson"
    },
    {
      "name": "Katherine A. Suess"
    },
    {
      "name": "Justin S. Spilker"
    },
    {
      "name": "Vincenzo R. D'Onofrio"
    },
    {
      "name": "Elia Cenci"
    },
    {
      "name": "Robert Feldmann"
    },
    {
      "name": "Alex J. Geiger"
    },
    {
      "name": "Andy D. Goulding"
    },
    {
      "name": "Mariska Kriek"
    },
    {
      "name": "Anika Kumar"
    },
    {
      "name": "Yuanze Luo"
    },
    {
      "name": "Desika Narayanan"
    },
    {
      "name": "Margaret E. Verrico"
    },
    {
      "name": "Pengpei Zhu"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5g70yby7jhpem.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.31307",
  "fulltext_url": null,
  "id": "5g70yby7jhpem",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.31307",
  "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",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7214679811",
  "pdf_url": "https://arxiv.org/pdf/2609.31307",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-25",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5g70yby7jhpem.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:24:52Z",
      "native_id": "2609.31307",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.31307"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "SQuIGG$\\vec{L}$E: Spatially resolved NIRSpec Pa$α$ reveals that the most CO-luminous, $z\\sim0.7$ post-starburst galaxies exhibit falling---but still active---star formation behind optically thick dust",
  "title_text": "SQuIGGL⃗E: Spatially resolved NIRSpec Paα reveals that the most CO-luminous, z∼0.7 post-starburst galaxies exhibit falling---but still active---star formation behind optically thick dust",
  "type": "preprint",
  "updated_at": "2026-10-30T12:24:52Z",
  "url": "https://research.draconitic.com/paper/5g70yby7jhpem",
  "venue": "arXiv",
  "versions": []
}