{
  "abstract": "The morphology of the central regions of high-redshift galaxies remains relatively unexplored, while recent case studies suggest that giant disks can emerge without first developing a prominent central spheroid. Here, we investigate the inner structures of a mass-complete sample of 45 massive galaxies at $z=3$ in the TNG50 simulation. Through double-Sérsic profile decomposition, isodensity ellipse fitting, intrinsic three-dimensional shape measurements, and stellar kinematics, we find that these central structures are ubiquitously flattened and rotation-supported with low Sérsic indices ($n \\lesssim 1$). This indicates that the central regions are predominantly nuclear disks and bars rather than bulges. Tracking their evolution, we show that these nuclear disks and bars emerge during gas-rich compaction and do not transform into spheroidal and dispersion-dominated systems until $z \\lesssim 1$, before which extended stellar disks have already developed. Our results suggest that massive disks can assemble around rotation-supported centers and bulge-deficient massive galaxies may be a common outcome of galaxy evolution.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.27460",
  "author_total": 11,
  "authors": [
    {
      "name": "Jianyuan Luo"
    },
    {
      "name": "Fangzhou Jiang"
    },
    {
      "name": "Jinning Liang"
    },
    {
      "name": "Boris S. Kalita"
    },
    {
      "name": "Pinsong Zhao"
    },
    {
      "name": "Jinyi Shangguan"
    },
    {
      "name": "Bingcheng Jin"
    },
    {
      "name": "Zeyu Gao"
    },
    {
      "name": "Weichen Wang"
    },
    {
      "name": "Luis C. Ho"
    },
    {
      "name": "Yingjie Peng"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5hhnzy962dxr9.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.27460",
  "fulltext_url": null,
  "id": "5hhnzy962dxr9",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.27460",
  "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": "W7214147379",
  "pdf_url": "https://arxiv.org/pdf/2609.27460",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-23",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5hhnzy962dxr9.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:56Z",
      "native_id": "2609.27460",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.27460"
    }
  ],
  "subjects": [
    {
      "field": "astronomy",
      "origin": "arxiv:astro-ph.GA",
      "subfield": "galaxies"
    }
  ],
  "title": "Ubiquitous nuclear disks and bars embedded in massive galaxies in the cosmic morning",
  "title_text": "Ubiquitous nuclear disks and bars embedded in massive galaxies in the cosmic morning",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:56Z",
  "url": "https://research.draconitic.com/paper/5hhnzy962dxr9",
  "venue": "arXiv",
  "versions": []
}