{
  "id": "2102.05679",
  "version": "v1",
  "published": "2021-02-10T19:00:04.000Z",
  "updated": "2021-02-10T19:00:04.000Z",
  "title": "The Kinematics of z ~ 6 Quasar Host Galaxies",
  "authors": [
    "Marcel Neeleman",
    "Mladen Novak",
    "Bram P. Venemans",
    "Fabian Walter",
    "Roberto Decarli",
    "Melanie Kaasinen",
    "Jan-Torge Schindler",
    "Eduardo Banados",
    "Chris L. Carilli",
    "Alyssa B. Drake",
    "Xiaohui Fan",
    "Hans-Walter Rix"
  ],
  "comment": "33 pages. Kinematic fitting code is available at https://github.com/mneeleman/qubefit",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We explore the kinematics of 27 z~6 quasar host galaxies observed in [CII]-158 micron ([CII]) emission with the Atacama Large Millimeter/sub-millimeter Array at a resolution of ~0.25''. We find that nine of the galaxies show disturbed [CII] emission, either due to a close companion galaxy or recent merger. Ten galaxies have smooth velocity gradients consistent with the emission arising from a gaseous disk. The remaining eight quasar host galaxies show no velocity gradient, suggesting that the gas in these systems is dispersion-dominated. All galaxies show high velocity dispersions with a mean of 129+-10 km/s. To provide an estimate of the dynamical mass within twice the half-light radius of the quasar host galaxy, we model the kinematics of the [CII] emission line using our publicly available kinematic fitting code, qubefit. This results in a mean dynamical mass of 5.0+-0.8(+-3.5) x 10^10 Msun. Comparison between the dynamical mass and the mass of the supermassive black hole reveals that the sample falls above the locally derived bulge mass--black hole mass relation at 2.4sigma significance. This result is robust even if we account for the large systematic uncertainties. Using several different estimators for the molecular mass, we estimate a gas mass fraction of >10%, indicating gas makes up a large fraction of the baryonic mass of z~6 quasar host galaxies. Finally, we speculate that the large variety in [CII] kinematics is an indication that gas accretion onto z~6 super massive black holes is not caused by a single precipitating factor.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2021-02-10T19:00:04.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "quasar host galaxy",
      "derived bulge mass-black hole",
      "dynamical mass",
      "bulge mass-black hole mass relation",
      "smooth velocity gradients consistent"
    ],
    "tags": [
      "github project"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 33,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}