{
  "id": "1811.11192",
  "version": "v1",
  "published": "2018-11-27T19:00:12.000Z",
  "updated": "2018-11-27T19:00:12.000Z",
  "title": "Cosmic Dawn II (CoDa II): a new radiation-hydrodynamics simulation of the self-consistent coupling of galaxy formation and reionization",
  "authors": [
    "Pierre Ocvirk",
    "Dominique Aubert",
    "Jenny G. Sorce",
    "Paul R. Shapiro",
    "Nicolas Deparis",
    "Taha Dawoodbhoy",
    "Joseph Lewis",
    "Romain Teyssier",
    "Gustavo Yepes",
    "Stefan Gottlöber",
    "Kyungjin Ahn",
    "Ilian T. Iliev",
    "Yehuda Hoffman"
  ],
  "comment": "19 pages, 9 figures, submitted to MNRAS",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "Cosmic Dawn II (CoDa II) is a new, fully-coupled radiation-hydrodynamics simulation of cosmic reionization and galaxy formation and their mutual impact, to redshift z < 6. With $4096^3$ particles and cells in a 94 Mpc box, it is large enough to model global reionization and its feedback on galaxy formation while resolving all haloes above $10^8$ M$_\\odot$. Using a constrained realization of {\\Lambda}CDM constructed from galaxy survey data to reproduce the large-scale structure and familiar objects of the present-day Local Universe, CoDa II serves to model both global and local reionization, including its impact on the Local Group. Using the same hybrid CPU-GPU code RAMSES-CUDATON as CoDa I in Ocvirk et al. (2016), CoDa II modified and re-calibrated the subgrid star-formation algorithm, making reionization end earlier, at z $\\gtrsim 6$, thereby better matching the observations of intergalactic Lyman-alpha opacity from quasar spectra and electron-scattering optical depth from cosmic microwave background fluctuations. The post-reionization UV background intensity is somewhat high, however, making the H I fraction after overlap lower than observed, a possible sign of missing bound-free opacity from unresolved substructure. CoDa II predicts a UV continuum luminosity function in good agreement with observations of high-z galaxies, especially at z = 6. The cosmic star formation rate density from M1600 < -17 galaxies is only 63% (18%) of the total in all haloes at z = 6 (z = 10). As in CoDa I, reionization feedback suppresses star formation in haloes below $\\sim 2 \\times 10^9 {\\rm{M}}_\\odot$ , though suppression here is less extreme, a possible consequence of modifying the star-formation algorithm. Suppression is environment-dependent, occurring earlier (later) in overdense (underdense) regions, in response to their local reionization times.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-11-27T19:00:12.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "galaxy formation",
      "radiation-hydrodynamics simulation",
      "cosmic dawn",
      "self-consistent coupling",
      "reionization feedback suppresses star formation"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 19,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}