{
  "abstract": "Environmental density correlates with galaxy properties in the local Universe, but how and when these trends emerge is unclear: at cosmic noon, large-scale structures are still assembling and galaxies quench rapidly for debated reasons. We study how the formation and quenching histories of massive galaxies at $1.7<z<3.5$ depend on environment, using two independent tracers: galaxy number density ($δ_\\#$) from COSMOS-Web and intergalactic neutral hydrogen ($δ_{HI}$, cool gas) from LATIS Ly$α$ tomography. We combine 139 Blue Jay JWST/NIRSpec galaxies with 57 DAWN JWST Archive prism spectra in COSMOS, deriving stellar masses, star formation histories, dust attenuation, and Na\\,{\\sc d} outflow rates from joint spectro-photometric \\texttt{Prospector} fits. In massive quiescent galaxies, the formation-to-quenching interval increases with density. AGN and Na\\,{\\sc d} outflows are confined to $δ_\\#<0.5$ and elevated Ly$α$ absorption ($δ_{HI}>1$), mostly in massive quiescent galaxies showing both. About 65\\% of the sample follows a correlation between the tracers; two outlier regions stand out. A galaxy-rich, gas-poor region ($δ_\\#>2$, $δ_{HI}<1$) coincides with one of the most massive Hyperion protocluster cores, where the gas is plausibly fully ionized; its quiescent galaxies formed earlier and lack significant AGN activity and outflows. A galaxy-poor, gas-rich region ($δ_\\#<1$, $δ_{HI}>1$), within 60 cMpc of the densest Hyperion cores, hosts rapidly quenched galaxies with a high incidence of AGN and outflows. This \\emph{developing environment}, distinct from both mature protoclusters and the field, likely traces massive halos still assembling. Galaxy counts alone cannot capture the environment at cosmic noon: jointly mapping galaxies and cool gas is crucial to understand how environment regulates gas accretion, star formation, and quenching.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2611.00190",
  "author_total": 18,
  "authors": [
    {
      "name": "Amir H. Khoram"
    },
    {
      "name": "Sirio Belli"
    },
    {
      "name": "Trevor Mendel"
    },
    {
      "name": "Letizia Bugiani"
    },
    {
      "name": "Matteo Sapori"
    },
    {
      "name": "Andrew B. Newman"
    },
    {
      "name": "Hossein Hatamnia"
    },
    {
      "name": "Finn Giddings"
    },
    {
      "name": "Rebecca L. Davies"
    },
    {
      "name": "Olga Cucciati"
    },
    {
      "name": "Bianca Poggianti"
    },
    {
      "name": "Amirnezam Amiri"
    },
    {
      "name": "Anita Zanella"
    },
    {
      "name": "Tianmu Gao"
    },
    {
      "name": "Gabriel Maheson"
    },
    {
      "name": "Stefano Sotira"
    },
    {
      "name": "Caterina Liboni"
    },
    {
      "name": "Giulia Papini"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/dq44br3dnwj2k.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2611.00190",
  "fulltext_url": null,
  "id": "dq44br3dnwj2k",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2611.00190",
  "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/2611.00190",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-01",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/dq44br3dnwj2k.ris",
  "sources": [
    {
      "first_seen": "2026-11-03T12:20:59Z",
      "native_id": "2611.00190",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2611.00190"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Developing Environments: Formation and Quenching at Cosmic Noon Traced by the Large-scale Distribution of Gas and Galaxies",
  "title_text": "Developing Environments: Formation and Quenching at Cosmic Noon Traced by the Large-scale Distribution of Gas and Galaxies",
  "type": "preprint",
  "updated_at": "2026-11-06T18:21:01Z",
  "url": "https://research.draconitic.com/paper/dq44br3dnwj2k",
  "venue": "arXiv",
  "versions": []
}