{
  "abstract": "We present the results from follow-up spectroscopy of three protocluster candidates at $z\\sim 3$, selected as overdense regions of U-dropout galaxies in the wide-field imaging of the Hyper SuprimeCam Subaru Strategic Programme. All three targets exhibit tight clustering in three-dimensional space, i.e. on the sky ($\\gt 4\\sigma$ overdensity) and in redshift ($\\gt 98.4 {{\\ \\rm per\\ cent}}$ confidence), making for clear evidence of genuine protoclusters. Since these three protoclusters are identified by the same data set and technique, they represent a good sample to study the diversity of protocluster properties with minimal observational biases. Although the average population across the three protoclusters is consistent with field galaxies, each protocluster individually exhibits distinguishing properties from each other or from field galaxies. In one protocluster, member galaxies stand out by a higher Ly $\\alpha$ equivalent width ($EW_0$), and massive members that are still highly star-forming. In contrast, relatively more suppressed star formation appears in another protocluster where the Ly $\\alpha$ $EW_0$ of member galaxies is systematically lower. These variations can be attributed to differences in the developmental phase of protoclusters. If the presence of quenching galaxies indicates a more mature system, galaxies with stronger Ly $\\alpha$ emissions may be more prevalent in the earlier stages of cluster formation. The uniform approach to searching protoclusters on which this study builds enables us to link observed variations at the onset of cosmic noon to different pathways in the history of cluster formation.",
  "abstract_shown": true,
  "affiliations": [
    "Astronomical Institute, Tohoku University , 6-3, Aramaki, Aoba, Sendai, Miyagi, 980-8578 ,",
    "Department of Astronomy, University of Tokyo , 7-3-1, Hongo, Bunkyo, Tokyo 113-0033 ,",
    "Center for the Early Universe, The University of Tokyo , 7-3-1 Hongo, Bunkyo, Tokyo, 113-0033 ,",
    "Department of Physics, University of Bath , Claverton Down, Bath BA2 7AY ,",
    "Department of Astronomy & Physics and Institute for Computational Astrophysics, Saint Mary’s University , 923 Robie Street, Halifax, NS B3H 3C3 ,",
    "School of Physics, HH Wills Physics Laboratory, University of Bristol , Tyndall Avenue, Bristol BS8 1TL ,",
    "Institute for Cosmic Ray Research, The University of Tokyo , 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba, 277-8582 ,",
    "Department of Physics and Astronomy, School of Science, Kwansei Gakuin University , Gakuen Uegahara, Sanda, Hyogo 669-1330 ,",
    "National Institute of Information and Communication Technologies , 893-1 Hirai, Kashima, Ibaraki 314-8501 ,"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 9,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Jun Toshikawa",
      "orcid": "0000-0001-5394-242X"
    },
    {
      "affs": [
        1
      ],
      "name": "Kentaro Koretomo",
      "orcid": "0009-0001-5183-2945"
    },
    {
      "affs": [
        1,
        2
      ],
      "name": "Nobunari Kashikawa",
      "orcid": "0000-0003-3954-4219"
    },
    {
      "affs": [
        3
      ],
      "name": "Stijn Wuyts",
      "orcid": "0000-0003-3735-1931"
    },
    {
      "affs": [
        4
      ],
      "name": "Marcin Sawicki",
      "orcid": "0000-0002-7712-7857"
    },
    {
      "affs": [
        5
      ],
      "name": "Malcolm N Bremer"
    },
    {
      "affs": [
        6
      ],
      "name": "Yoshiaki Ono"
    },
    {
      "affs": [
        7
      ],
      "name": "Mariko Kubo",
      "orcid": "0000-0002-7598-5292"
    },
    {
      "affs": [
        8
      ],
      "name": "Tomoki Saito"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/bvewz24txegx3.bib",
  "cited_by": 0,
  "doi": "10.1093/mnras/stag1862",
  "fulltext_url": null,
  "id": "bvewz24txegx3",
  "issns": [
    "0035-8711",
    "1365-2966"
  ],
  "landing_url": "https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1862/8865325",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "3103|Galaxies: Formation, Evolution, Phenomena"
    ]
  ],
  "openalex": "W7220735211",
  "pdf_url": "https://academic.oup.com/mnras/advance-article-pdf/doi/10.1093/mnras/stag1862/71606448/stag1862.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-05",
  "publisher": "Oxford University Press (OUP)",
  "ris": "https://research.draconitic.com/paper/bvewz24txegx3.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:17Z",
      "native_id": "10.1093/mnras/stag1862",
      "source": "crossref",
      "url": "https://academic.oup.com/mnras/article/doi/10.1093/mnras/stag1862/8865325"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "openalex:3103|Galaxies: Formation, Evolution, Phenomena",
      "subfield": "galaxies"
    }
  ],
  "title": "Diverse protoclusters at z ∼ 3 disclosed by systematic spectroscopy",
  "title_text": "Diverse protoclusters at z ∼ 3 disclosed by systematic spectroscopy",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:17Z",
  "url": "https://research.draconitic.com/paper/bvewz24txegx3",
  "venue": "Monthly Notices of the Royal Astronomical Society",
  "versions": []
}