{
  "abstract": "The visibility of Ly$α$ emission during the epoch of reionization depends on both galaxy properties and the transmission of Ly$α$ photons through the intergalactic medium (IGM). Using JWST/NIRCam F470N imaging, we identify a prominent projected overdensity of H$α$ emitters (HAEs) at $z\\simeq6.2$ in CEERS field. We use Subaru/HSC NB872 imaging to measure their Ly$α$ fluxes and compare the Ly$α$ visibility of galaxies within $2'$ of the density center with that of galaxies outside this region. The Ly$α$-emitter (LAE) fraction is $0.41^{+0.15}_{-0.14}$ in the inner region and $0.27^{+0.19}_{-0.15}$ in the outer region. Stacking the H$α$ and Ly$α$ images gives median Ly$α$ escape fractions of $0.100^{+0.091}_{-0.053}$ and $0.063^{+0.130}_{-0.063}$ in the inner and outer regions, respectively. Both measures indicate higher Ly$α$ visibility in the inner region, although only at modest significance. HAEs closer to the density center are systematically more massive and have redder UV slopes, which instead favor lower Ly$α$ escape. The environmental difference in Ly$α$ visibility is therefore difficult to explain solely by variations in underlying galaxy population. Our results are consistent with reduced Ly$α$ attenuation through a more highly ionized IGM in the overdense region, as expected if large H\\,{\\sc ii} bubbles preferentially form around such galaxy overdensities. The wide-field LAE distribution provides complementary support for this scenario, as the HAE-defined density center coincides with the strongest LAE overdensity across the $1.4\\,{\\rm deg}^2$ HSC field. These findings highlight the importance of spatial variations in IGM attenuation in shaping Ly$α$ visibility near the end of reionization.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.35221",
  "author_total": 16,
  "authors": [
    {
      "name": "Shunta Shimizu"
    },
    {
      "name": "Nobunari Kashikawa"
    },
    {
      "name": "Junya Arita"
    },
    {
      "name": "Ryo Emori"
    },
    {
      "name": "Kohei Inayoshi"
    },
    {
      "name": "Akio K. Inoue"
    },
    {
      "name": "Kei Ito"
    },
    {
      "name": "Satoshi Kikuta"
    },
    {
      "name": "Kentaro Koretomo"
    },
    {
      "name": "Mariko Kubo"
    },
    {
      "name": "Yongming Liang"
    },
    {
      "name": "Rieko Momose"
    },
    {
      "name": "Kentaro Nagamine"
    },
    {
      "name": "Masafusa Onoue"
    },
    {
      "name": "Rhythm Shimakawa"
    },
    {
      "name": "Hisakazu Uchiyama"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8rg209wjbtwch.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.35221",
  "fulltext_url": null,
  "id": "8rg209wjbtwch",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.35221",
  "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"
    ],
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7214762679",
  "pdf_url": "https://arxiv.org/pdf/2609.35221",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-28",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/8rg209wjbtwch.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:25:12Z",
      "native_id": "2609.35221",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.35221"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Probing Spatial Variations in IGM Transmission: Higher Ly$α$ Visibility in an H$α$-Selected Galaxy Overdensity at $z\\simeq6.2$",
  "title_text": "Probing Spatial Variations in IGM Transmission: Higher Lyα Visibility in an Hα-Selected Galaxy Overdensity at z≃6.2",
  "type": "preprint",
  "updated_at": "2026-10-30T12:25:12Z",
  "url": "https://research.draconitic.com/paper/8rg209wjbtwch",
  "venue": "arXiv",
  "versions": []
}