{
  "id": "1809.01545",
  "version": "v1",
  "published": "2018-09-05T14:34:33.000Z",
  "updated": "2018-09-05T14:34:33.000Z",
  "title": "Constraints On Duty Cycles Of Quasars At Z $\\sim$ 6",
  "authors": [
    "Huanqing Chen",
    "Nickolay Y. Gnedin"
  ],
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We study the mass of quasar-hosting dark matter halos at z $\\sim$ 6 and further constrain the fraction of dark matter halos hosting an active quasar $f_{on}$ and the quasar beaming angle $i_{\\rm max}$ using observations of CII lines in the literature. We make assumptions that (1) more massive halos host brighter quasars, (2) a fraction of the halos host active quasars with a certain beaming angle, (3) cold gas in galaxies has rotational velocity $V_{\\rm circ}=\\alpha V_{\\rm max}$, and that (4) quasars point randomly on the sky. We find that for a choice of specific $\\alpha \\gtrsim 1$, the most likely solution has $f_{\\rm on} < 0.01$, corresponding to a small duty cycle of quasar activity. However, if we marginalize over $\\alpha$, for some choices of a prior a second solution with $f_{\\rm on}=1$ appears. Overall, our the constraints are highly sensitive to $\\alpha$ and hence inconclusive. Stronger constraints on $f_{\\rm on}$ can be made if we better understand the dynamics of cold gas in these galaxies.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-09-05T14:34:33.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "constraints",
      "cold gas",
      "massive halos host brighter quasars",
      "quasar-hosting dark matter halos",
      "small duty cycle"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}