{
  "id": "1707.03014",
  "version": "v1",
  "published": "2017-07-10T18:47:45.000Z",
  "updated": "2017-07-10T18:47:45.000Z",
  "title": "Quasar outflows at $z \\geq 6$: the impact on the host galaxies",
  "authors": [
    "Paramita Barai",
    "Simona Gallerani",
    "Andrea Pallottini",
    "Andrea Ferrara",
    "Alessandro Marconi",
    "Claudia Cicone",
    "Roberto Maiolino",
    "Stefano Carniani"
  ],
  "comment": "17 pages (excluding references and appendix), 11 figures, Submitted",
  "categories": [
    "astro-ph.GA",
    "astro-ph.HE"
  ],
  "abstract": "We investigate quasar outflows at $z \\geq 6$ by performing zoom-in cosmological hydrodynamical simulations. By employing the SPH code GADGET-3, we zoom in the $2 R_{200}$ region around a $2 \\times 10^{12} M_{\\odot}$ halo at $z = 6$, inside a $(500 ~ {\\rm Mpc})^3$ comoving volume. We compare the results of our AGN runs with a control simulation in which only stellar/SN feedback is considered. Seeding $10^5 M_{\\odot}$ BHs at the centers of $10^{9} M_{\\odot}$ halos, we find the following results. BHs accrete gas at the Eddington rate over $z = 9 - 6$. At $z = 6$, our most-massive BH has grown to $M_{\\rm BH} = 4 \\times 10^9 M_{\\odot}$. Fast ($v_{r} > 1000$ km/s), powerful ($\\dot{M}_{\\rm out} \\sim 2000 M_{\\odot}$/yr) outflows of shock-heated low-density gas form at $z \\sim 7$, and propagate up to hundreds kpc. Star-formation is quenched over $z = 8 - 6$, and the total SFR (SFR surface density near the galaxy center) is reduced by a factor of $5$ ($1000$). We analyse the relative contribution of multiple physical process: (i) disrupting cosmic filamentary cold gas inflows, (ii) reducing central gas density, (iii) ejecting gas outside the galaxy; and find that AGN feedback has the following effects at $z = 6$. The inflowing gas mass fraction is reduced by $\\sim 12 \\%$, the high-density gas fraction is lowered by $\\sim 13 \\%$, and $\\sim 20 \\%$ of the gas outflows at a speed larger than the escape velocity ($500$ km/s). We conclude that quasar-host galaxies at $z \\geq 6$ are accreting non-negligible amount of cosmic gas, nevertheless AGN feedback quenches their star formation dominantly by powerful outflows ejecting gas out of the host galaxy halo.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-07-10T18:47:45.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "host galaxy",
      "quasar outflows",
      "zoom-in cosmological hydrodynamical simulations",
      "cosmic filamentary cold gas inflows",
      "disrupting cosmic filamentary cold gas"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}