{
  "abstract": "Massive galaxies provide strong tests of galaxy formation models, yet a comprehensive spectroscopic view of their properties and demographics in the early Universe has remained elusive. Here we present a JWST spectroscopic census of the 200 most massive galaxies at zspec~3-15, selected using an evolving stellar-mass threshold motivated by the halo mass function and anchored at log(Mstar)>10 at z~5. These galaxies represent the top 3% most massive systems among all publicly available prism observations. We derive their physical properties through joint SED fitting of spectroscopy and photometry, and construct a clean massive galaxy sample after removing LRDs and broad-line AGN contaminants. We find that the massive galaxy population evolves strongly with redshift: normal SFGs (Av<1 mag) dominate at z>~6, while dusty SFGs (Av>1 mag) and QGs become more common toward lower redshift. Dust attenuation decreases systematically toward higher redshift. We identify 29 massive QGs, including a population of recently quenched systems whose star formation declined rapidly within the past ~100 Myr. We further show that both the traditional UVJ and recently proposed (ugi)s selections suffer substantial inconsistency with the most massive galaxies at z>3, motivating a revised (ugi)s criterion calibrated using our spectroscopic sample. The inferred formation histories suggest at least two pathways toward quiescence: a dust-enriched pathway linking normal SFGs, dusty SFGs, and QGs, and a more direct pathway connecting normal SFGs and QGs. Massive normal SFGs appear to grow through both relatively gradual and rapid assembly modes. Together, these results suggest that rapid stellar-mass assembly, dust enrichment, and quenching were already shaping the evolutionary pathways of the most massive galaxies within the first billion years after the Big Bang.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2606.30802",
  "author_total": 29,
  "authors": [
    {
      "name": "Mengyuan Xiao"
    },
    {
      "name": "Pascal A. Oesch"
    },
    {
      "name": "Longji Bing"
    },
    {
      "name": "Rashmi Gottumukkala"
    },
    {
      "name": "Rui Marques-Chaves"
    },
    {
      "name": "Gabriel Brammer"
    },
    {
      "name": "Miroslava Dessauges-Zavadsky"
    },
    {
      "name": "David Elbaz"
    },
    {
      "name": "Songnan Qi"
    },
    {
      "name": "Anurag Amol Sawarkar"
    },
    {
      "name": "Manuel Aravena"
    },
    {
      "name": "Matthieu Béthermin"
    },
    {
      "name": "Rachel Bezanson"
    },
    {
      "name": "Rychard Bouwens"
    },
    {
      "name": "Caitlin Casey"
    },
    {
      "name": "Pieter van Dokkum"
    },
    {
      "name": "Andreas L. Faisst"
    },
    {
      "name": "Yoshinobu Fudamoto"
    },
    {
      "name": "Anna de Graaff"
    },
    {
      "name": "Olivier Ilbert"
    },
    {
      "name": "Garth Illingworth"
    },
    {
      "name": "Guilaine Lagache"
    },
    {
      "name": "Benjamin Magnelli"
    },
    {
      "name": "Jorryt Matthee"
    },
    {
      "name": "Yurina Nakazato"
    },
    {
      "name": "Daniel Schaerer"
    },
    {
      "name": "Sune Toft"
    },
    {
      "name": "Katherine E. Whitaker"
    },
    {
      "name": "Christina C. Williams"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/ead8k5m8qwhsz.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2606.30802",
  "fulltext_url": null,
  "id": "ead8k5m8qwhsz",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2606.30802",
  "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": "W7166842897",
  "pdf_url": "https://arxiv.org/pdf/2606.30802",
  "pmcid": null,
  "pmid": null,
  "published": "2026-11-04",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/ead8k5m8qwhsz.ris",
  "sources": [
    {
      "first_seen": "2026-11-06T18:21:30Z",
      "native_id": "2606.30802",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2606.30802"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "A Census of the 200 Most Massive Galaxies Spectroscopically Observed with JWST at zspec $\\sim$3-15",
  "title_text": "A Census of the 200 Most Massive Galaxies Spectroscopically Observed with JWST at zspec ∼3-15",
  "type": "preprint",
  "updated_at": "2026-11-09T00:20:33Z",
  "url": "https://research.draconitic.com/paper/ead8k5m8qwhsz",
  "venue": "arXiv",
  "versions": []
}