{
  "id": "2401.04765",
  "version": "v1",
  "published": "2024-01-09T19:00:01.000Z",
  "updated": "2024-01-09T19:00:01.000Z",
  "title": "ALMA survey of a massive node of the Cosmic Web at z~3. I. Discovery of a large overdensity of CO emitters",
  "authors": [
    "A. Pensabene",
    "S. Cantalupo",
    "C. Cicone",
    "R. Decarli",
    "M. Galbiati",
    "M. Ginolfi",
    "S. de Beer",
    "M. Fossati",
    "M. Fumagalli",
    "T. Lazeyras",
    "G. Pezzulli",
    "A. Travascio",
    "W. Wang",
    "J. Matthee",
    "M. V. Maseda"
  ],
  "comment": "25 pages, 14 figures. Accepted for publication in A&A",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "Sub-mm surveys toward overdense regions in the early Universe are essential to uncover the obscured star-formation and the cold gas content of assembling galaxies within massive dark matter halos. In this work, we present deep ALMA mosaic observations covering an area of $\\sim 2'\\times2'$ around MQN01 (MUSE Quasar Nebula 01), one of the largest and brightest Ly-$\\alpha$ emitting nebulae discovered thus far surrounding a radio-quiet quasar at $z\\simeq3.25$. Our observations target the 1.2- and the 3-mm dust continuum, as well as the carbon monoxide CO(4-3) transition in galaxies in the vicinity of the quasar. We identify a robust sample of eleven CO line-emitting galaxies (including a closely-separated quasar companion) which lie within $\\pm 4000\\,{\\rm km\\,s^{-1}}$ relatively to the quasar systemic redshift. A fraction of these objects are missed in previous deep rest-frame optical/UV surveys thus highlighting the critical role of (sub-)mm imaging. We also detect a total of eleven sources revealed in their 1.2-mm dust continuum with six of them having either high-fidelity spectroscopic redshift information from rest-frame UV metal absorptions, or CO line which place them in the same narrow redshift range. A comparison of the CO luminosity function (LF) and 1.2-mm number count density with that of the general fields points to a galaxy overdensity of $\\delta > 10$. We find evidence of a systematic flattening at the bright-end of the CO LF with respect to the trend measured in blank fields. Our findings reveal that galaxies in dense regions at $z\\sim3$ are more massive and significantly richer in molecular gas than galaxies in fields, hence enabling a faster and accelerated assembly. This is the first of a series of studies to characterize one of the densest regions of the Universe found so far at $z > 3$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2024-01-09T19:00:01.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "alma survey",
      "cosmic web",
      "large overdensity",
      "massive node",
      "alma mosaic observations covering"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 25,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}