{
  "abstract": "We present BRIDGE-I, a metallicity survey of \\HI-selected absorbers probing ``CGM-like'' gas ($16.4\\leq \\log N_{\\rm HI}<20.3$) at Cosmic Noon ($1\\leq z \\leq2.2$), the epoch of peak star formation and AGN activity. Combining archival HST UV spectra with Keck/HIRES and VLT/UVES optical spectra, we estimate metallicities and physical conditions for 105 absorbers. The Cosmic Noon metallicity distribution (median $[\\rm{X/H}]=-1.19$) is statistically indistinguishable from that at $z<1$ ($-1.18$) but differs significantly from $z>2.2$ ($-2.02$). This plateau is driven by the most diffuse absorbers ($16.4\\leq \\log N_{\\rm HI}<17.2$), which reach their $z<1$ enrichment level by Cosmic Noon, whereas denser absorbers remain more metal-poor than their $z<1$ counterparts and continue to be enriched at later times. Unlike at $z>2.2$, no absorber falls below $[\\rm{X/H}]=-3.5$, indicating no pristine CGM-like gas at Cosmic Noon. Absorbers in BRIDGE-I trace overdensities of $400\\lesssim δ_b\\lesssim2200$, higher than at $z>2.2$. Mean $N_{\\rm HI}$ differs by a factor of 400 across absorber types, but mean total hydrogen column by only 2.5, as higher $N_{\\rm HI}$ is offset by a higher neutral fraction. The absorber classes thus differ in ionization state and metallicity rather than the total gas content. A metallicity floor of $[\\rm{X/H}]\\sim-2.0$ emerges for $\\log N_{\\rm HI}>19.0$ absorbers, indicating that denser, more ISM-like gas is well mixed as a population, while more diffuse gas retains a metal-poor population that is not yet fully mixed.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.26785",
  "author_total": 6,
  "authors": [
    {
      "name": "Saloni Deepak"
    },
    {
      "name": "Nicolas Lehner"
    },
    {
      "name": "J. Christopher Howk"
    },
    {
      "name": "John O'Meara"
    },
    {
      "name": "Celine Peroux"
    },
    {
      "name": "J. Xavier Prochaska"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8p6bhv2aczb80.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.26785",
  "fulltext_url": null,
  "id": "8p6bhv2aczb80",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.26785",
  "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": "W7214118610",
  "pdf_url": "https://arxiv.org/pdf/2609.26785",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8p6bhv2aczb80.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:39Z",
      "native_id": "2609.26785",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.26785"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "The BRIDGE Survey. I. Metallicities and Physical Properties of Gas Probing the Circumgalactic Medium at Cosmic Noon",
  "title_text": "The BRIDGE Survey. I. Metallicities and Physical Properties of Gas Probing the Circumgalactic Medium at Cosmic Noon",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:39Z",
  "url": "https://research.draconitic.com/paper/8p6bhv2aczb80",
  "venue": "arXiv",
  "versions": []
}