{
  "annotation_id": "c4ec857a-9c5d-420d-a153-58c6af550015",
  "date_created": "2026-02-17T05:53:08.807000Z",
  "date_modified": "2026-02-17T05:53:08.807000Z",
  "file_hash": "3cbe54dfde3e0922861499dd43e063b6106e278769d529ffe6ebdc18a792a0e7",
  "private": false,
  "record": {
    "abstract": "We analyzed the 25 richest galaxy groups in COSMOS-Web at z = 0.18-3.65, identified via the AMICO algorithm. These groups contain 20-30 galaxies with high (\u003e75%) membership probability. Our study reveals both passive-density and active-density relations: late-type galaxies (LTGs) prefer higher central overdensities than early-type galaxies (ETGs) across all groups, and many massive LTGs exhibit colors typical of quiescent galaxies. We identify red sequences (RS) in 5 groups, prominently established at z \u003c 1, with early emergence in the RS locus up to z ~ 2.2.\n  This suggests group environments represent a transitional phase where star formation quenching precedes morphological transformation, contrasting with the classical morphology-density relation in rich clusters. In the central regions (~33 arcsec / 100 kpc from centers), we identified 86 galaxies: 23 (~27%) ETGs and 63 (~73%) LTGs. High-mass galaxies (M_star \u003e 10^10.5 M_sun) undergo rapid quenching over ~1 Gyr, becoming predominantly spheroidal ETGs. This indicates morphological transformation accelerates in massive systems during peak cosmic star formation. Intermediate-mass galaxies (10^9 \u003c M_star/M_sun \u003c 10^10.5) show mild quenching, while low-mass galaxies (M_star \u003c 10^9 M_sun) remain largely star-forming; here, environmental processes suppress star formation without destroying disks, suggesting group quenching operates on longer timescales than mass quenching. Overall, mass-dependent quenching dominates the high-mass end, while environment shapes lower-mass systems. The HLAGN fraction for both groups and field increases with redshift, peaking at z ~ 2, with groups consistently showing higher fractions. We suggest AGN feedback partially drives rapid quenching in high-mass galaxies, while mergers may trigger AGN activity.",
    "arxiv_id": "2601.06297",
    "authors": [
      "Z. Ghaffari",
      "G. Gozaliasl",
      "A. Biviano",
      "G. Toni",
      "S. Taamoli",
      "M. Maturi",
      "L. Moscardini",
      "A. Zacchei",
      "F. Gentile",
      "M. Haas",
      "H. Akins",
      "R. C. Arango-Toro",
      "Y. Cheng",
      "C. Casey",
      "M. Franco",
      "S. Harish",
      "H. Hatamnia",
      "O. Ilbert",
      "J. Kartaltepe",
      "A. H. Khostovan",
      "A. M. Koekemoer",
      "D. Liu",
      "G. A. Mamon",
      "H. J. McCracken",
      "J. McKinney",
      "J. Rhodes",
      "B. Robertson",
      "M. Shuntov",
      "L. Yang"
    ],
    "categories": [
      "astro-ph.GA"
    ],
    "license": "http://arxiv.org/licenses/nonexclusive-distrib/1.0/",
    "title": "Star formation quenching precedes morphological transformation in COSMOS-WEB\u0027s richest galaxy groups",
    "url": "https://arxiv.org/abs/2601.06297",
    "version": "v1"
  },
  "schema_id": "dorsal/arxiv",
  "source": {
    "execution_id": "04354e29-9e76-4a7c-af79-ebcec72e5527",
    "id": "arXiv Dataset",
    "type": "Model",
    "variant": "snapshot-2026-01-17",
    "version": "0.1.0"
  },
  "user_id": 1000002
}