{
  "abstract": "We investigate UV absorption lines tracing cool gas in eight bright ($-21.9 < M_\\mathrm{UV} < -20.5$) galaxies at $z=7.2-10.6$ using deep archival JWST/NIRSpec medium-resolution spectra. The eight galaxies were homogeneously selected based on wavelength coverage and data quality from 362 galaxies at $z>7$ available to date, and all eight were observed as part of the SPURS program. We identify multiple absorption lines of low-ionization species (LIS) in five galaxies, while the remaining three show only one or no significant detections. The average LIS equivalent widths $\\mathrm{EW}_{\\mathrm{LIS}}$ indicate weaker absorption lines in compact ($r_\\mathrm{e}\\lesssim100$ pc) galaxies with high $L_{\\mathrm{H}β}/L_{\\mathrm{UV}}$ and $Σ_{\\mathrm{SFR}}$, suggestive of absorption-line suppression due to intense star formation or nuclear activity. We simultaneously fit multiple LIS lines, accounting for both covering fraction $C_f$ and column density $N$, and find that the five galaxies follow the local $C_f$-$N$ relation. Through the LIS-line fitting, we derive chemical abundance ratios. The five galaxies have abundance ratios similar to those of damped Ly$α$ (DLA) systems at $z\\sim5-7$ in the [Si/O]-[C/O] and [Fe/Si]-[Al/Si] planes, suggesting that their absorbing gas is similar to that of DLAs. We find that two galaxies at $z\\sim7$ are already highly Fe-enriched, with $\\mathrm{[Fe/Si]}\\simeq-0.2$, near the solar abundance ratio. While the high Fe enrichment may originate from early Type-Ia supernovae (SNe Ia) or pair-instability supernovae (PISNe), these two galaxies also show $\\mathrm{[Al/Si]}\\sim0$, with no signature of the strong odd-even effect expected from PISNe, in which odd-$Z$ elements are suppressed relative to even-$Z$ elements, favoring SNe Ia.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.08782",
  "author_total": 2,
  "authors": [
    {
      "name": "Minami Nakane"
    },
    {
      "name": "Masami Ouchi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/4s46tymb79gea.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.08782",
  "fulltext_url": null,
  "id": "4s46tymb79gea",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.08782",
  "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": "W7164014898",
  "pdf_url": "https://arxiv.org/pdf/2606.08782",
  "pmcid": null,
  "pmid": null,
  "published": "2026-08-31",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/4s46tymb79gea.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:00Z",
      "native_id": "2606.08782",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.08782"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "JWST Absorption-Line Analysis of UV-Bright Galaxies at $z=7.2-10.6$: Early Chemical Enrichment Traced by C, O, Mg, Al, Si, and Fe",
  "title_text": "JWST Absorption-Line Analysis of UV-Bright Galaxies at z=7.2−10.6: Early Chemical Enrichment Traced by C, O, Mg, Al, Si, and Fe",
  "type": "preprint",
  "updated_at": "2026-10-30T12:18:00Z",
  "url": "https://research.draconitic.com/paper/4s46tymb79gea",
  "venue": "arXiv",
  "versions": []
}