{
  "id": "2009.12372",
  "version": "v1",
  "published": "2020-09-25T18:00:00.000Z",
  "updated": "2020-09-25T18:00:00.000Z",
  "title": "A Complete Census of Circumgalactic \\MgII at Redshift z $\\lesssim$ 0.5",
  "authors": [
    "Yun-Hsin Huang",
    "Hsiao-Wen Chen",
    "Stephen A. Shectman",
    "Sean D. Johnson",
    "Fakhri S. Zahedy",
    "Jennifer E. Helsby",
    "Jean-René Gauthier",
    "Ian B. Thompson"
  ],
  "comment": "21 pages, 11 figures, submitted to MNRAS",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present a survey of MgII absorbing gas in the vicinity of 380 random galaxies, using 156 background quasi-stellar objects(QSOs) as absorption-line probes. The sample comprises 211 isolated (73 quiescent and 138 star-forming galaxies) and 43 non-isolated galaxies with sensitive constraints for both MgII absorption and Ha emission. The projected distances span a range from d=9 to 497 kpc, redshifts of the galaxies range from z=0.10 to 0.48, and rest-frame absolute B-band magnitudes range from $M_{\\rm B}=-16.7$ to $-22.8$. Our analysis shows that the rest-frame equivalent width of MgII, $W_r$(2796), depends on halo radius($R_h$), $B$-band luminosity($L_{\\rm B}$) and stellar mass ($M_{\\rm star}$) of the host galaxies, and declines steeply with increasing $d$ for isolated, star-forming galaxies. $W_r$(2796) exhibits no clear trend for either isolated, quiescent galaxies or non-isolated galaxies. The covering fraction of MgII absorbing gas $\\langle \\kappa \\rangle$ is high with $\\langle \\kappa \\rangle\\gtrsim 60$% at $<40$ kpc for isolated galaxies and declines rapidly to $\\langle \\kappa \\rangle\\approx 0$ at $d\\gtrsim100$ kpc. Within the gaseous radius, $\\langle \\kappa \\rangle$ depends sensitively on both $M_{\\rm star}$ and the specific star formation rate inferred from Ha. Different from massive quiescent halos, the observed velocity dispersion of MgII gas around star-forming galaxies is consistent with expectations from virial motion, which constrains individual clump mass to $m_{\\rm cl} \\gtrsim 10^5 \\,\\rm M_\\odot$ and cool gas accretion rate of $\\sim 0.7-2 \\,M_\\odot\\,\\rm yr^{-1}$. We find no strong azimuthal dependence of MgII absorption for either star-forming or quiescent galaxies. Our results highlight the need of a homogeneous, absorption-blind sample for establishing a holistic description of chemically-enriched gas in the circumgalactic space.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-09-25T18:00:00.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "complete census",
      "circumgalactic",
      "star-forming galaxies",
      "rest-frame absolute b-band magnitudes range",
      "mgii absorbing gas"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 21,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}