{
  "id": "1707.05238",
  "version": "v1",
  "published": "2017-07-17T15:38:27.000Z",
  "updated": "2017-07-17T15:38:27.000Z",
  "title": "Molecular gas in three z~7 quasar host galaxies",
  "authors": [
    "Bram Venemans",
    "Fabian Walter",
    "Roberto Decarli",
    "Carl Ferkinhoff",
    "Axel Weiss",
    "Joseph Findlay",
    "Richard McMahon",
    "Will Sutherland",
    "Rowin Meijerink"
  ],
  "comment": "12 pages, 6 figures. Accepted for publication in ApJ",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "We present ALMA band 3 observations of the CO(6-5), CO(7-6), and [CI] 369micron emission lines in three of the highest redshift quasar host galaxies at 6.6<z<6.9. These measurements constitute the highest-redshift CO detections to date. The target quasars have previously been detected in [CII] 158micron emission and the underlying far-infrared (FIR) dust continuum. We detect (spatially unresolved, at a resolution of >2\", or >14kpc) CO emission in all three quasar hosts. In two sources, we detect the continuum emission around 400micron (rest-frame), and in one source we detect [CI] at low significance. We derive molecular gas reservoirs of (1-3)x10^10 M_sun in the quasar hosts, i.e. approximately only 10 times the mass of their central supermassive black holes. The extrapolated [CII]-to-CO(1-0) luminosity ratio is 2500-4200, consistent with measurements in galaxies at lower redshift. The detection of the [CI] line in one quasar host galaxy and the limit on the [CI] emission in the other two hosts enables a first characterization of the physical properties of the interstellar medium in z~7 quasar hosts. In the sources, the derived global CO/[CII]/[CI] line ratios are consistent with expectations from photodissociation regions (PDR), but not X-ray dominated regions (XDR). This suggest that quantities derived from the molecular gas and dust emission are related to ongoing star-formation activity in the quasar hosts, providing further evidence that the quasar hosts studied here harbor intense starbursts in addition to their active nucleus.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-07-17T15:38:27.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "quasar host galaxy",
      "highest redshift quasar host galaxies",
      "derive molecular gas reservoirs",
      "369micron emission lines",
      "central supermassive black holes"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}