{
  "id": "1406.2691",
  "version": "v2",
  "published": "2014-06-10T20:00:07.000Z",
  "updated": "2015-02-12T15:49:50.000Z",
  "title": "Feedback from Active Galactic Nuclei: Energy- versus momentum-driving",
  "authors": [
    "Tiago Costa",
    "Debora Sijacki",
    "Martin G. Haehnelt"
  ],
  "comment": "25 pages, 17 figures, 1 table, MNRAS (accepted in August 2014 after minor revisions)",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "We employ hydrodynamical simulations using the moving-mesh code AREPO to investigate the role of energy and momentum input from Active Galactic Nuclei (AGN) in driving large-scale galactic outflows. We start by reproducing analytic solutions for both energy- and momentum-driven outflowing shells in simulations of a spherical isolated dark matter potential with gas in hydrostatic equilibrium and with no radiative cooling. We confirm that for this simplified setup, galactic outflows driven by a momentum input rate of order L_Edd/c can establish an M_BH - sigma relation with slope and normalisation similar to that observed. We show that momentum input at a rate of L_Edd/c is however insufficient to drive efficient outflows once cooling and gas inflows as predicted by cosmological simulations at resolved scales are taken into account. We argue that observed large-scale AGN-driven outflows are instead likely to be energy-driven and show that such outflows can reach momentum fluxes exceeding 10 L_Edd/c within the innermost 10 kpc of the galaxy. The outflows are highly anisotropic, with outflow rates and a velocity structure found to be inadequately described by spherical outflow models. We verify that the hot energy-driven outflowing gas is expected to be strongly affected by metal-line cooling, leading to significant amounts (>10^9 M_sun) of entrained cold gas.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-06-10T20:00:07.000Z",
      "comment": "24 pages, 17 figures, 1 table, MNRAS submitted",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2015-02-12T15:49:50.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "active galactic nuclei",
      "isolated dark matter potential",
      "galactic outflows",
      "hot energy-driven outflowing gas",
      "momentum input rate"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1093/mnras/stu1632",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2014,
      "month": "Nov",
      "volume": 444,
      "number": 3,
      "pages": 2355
    },
    "note": {
      "typesetting": "TeX",
      "pages": 25,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1300115,
      "adsabs": "2014MNRAS.444.2355C"
    }
  }
}