{
  "id": "2204.04167",
  "version": "v1",
  "published": "2022-04-08T16:29:06.000Z",
  "updated": "2022-04-08T16:29:06.000Z",
  "title": "An ultra-deep multi-band VLA survey of the faint radio sky (COSMOS-XS): New constraints on the cosmic star formation history",
  "authors": [
    "D. van der Vlugt",
    "J. A. Hodge",
    "H. S. B. Algera",
    "I. Smail",
    "S. K. Leslie",
    "J. F. Radcliffe",
    "D. A. Riechers",
    "H. Röttgering"
  ],
  "comment": "Submitted to ApJ; 27 pages, 13 figures, 4 tables",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We make use of ultra-deep 3 GHz Karl G. Jansky Very Large Array observations of the COSMOS field from the multi-band COSMOS-XS survey to infer radio luminosity functions (LFs) of star-forming galaxies (SFGs). Using $\\sim$1300 SFGs with redshifts out to $z\\sim4.6$, and fixing the faint and bright end shape of the radio LF to the local values, we find a strong redshift trend that can be fitted by pure luminosity evolution with the luminosity parameter given by $\\alpha_L \\propto (3.40 \\pm 0.11) - (0.48 \\pm 0.06)z$. We then combine the ultra-deep COSMOS-XS data-set with the shallower VLA-COSMOS $\\mathrm{3\\,GHz}$ large project data-set over the wider COSMOS field in order to fit for joint density+luminosity evolution, finding evidence for significant density evolution. By comparing the radio LFs to the observed far-infrared (FIR) and ultraviolet (UV) LFs, we find evidence of a significant underestimation of the UV LF by $21.6\\%\\, \\pm \\, 14.3 \\, \\%$ at high redshift ($3.3\\,<\\,z\\,<\\,4.6$, integrated down to $0.03\\,L^{\\star}_{z=3}$). We derive the cosmic star formation rate density (SFRD) by integrating the fitted radio LFs and find that the SFRD rises up to $z\\,\\sim\\,1.8$ and then declines more rapidly than previous radio-based estimates. A direct comparison between the radio SFRD and a recent UV-based SFRD, where we integrate both LFs down to a consistent limit ($0.038\\,L^{\\star}_{z=3}$), reveals that the discrepancy between the radio and UV LFs translates to a significant ($\\sim$1 dex) discrepancy in the derived SFRD at $z>3$, even assuming the latest dust corrections and without accounting for optically dark sources.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2022-04-08T16:29:06.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "cosmic star formation history",
      "ultra-deep multi-band vla survey",
      "faint radio sky",
      "star formation rate density"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 27,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}