{
  "id": "1407.4472",
  "version": "v2",
  "published": "2014-07-16T20:00:28.000Z",
  "updated": "2014-09-17T12:07:20.000Z",
  "title": "The Direct Collapse of a Massive Black Hole Seed Under the Influence of an Anisotropic Lyman-Werner Source",
  "authors": [
    "John A. Regan",
    "Peter H. Johansson",
    "John H. Wise"
  ],
  "comment": "18 pages. ApJ accepted, with minor changes to submitted version. High resolution movies available at http://www.helsinki.fi/~regan/visualisations.html",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "The direct collapse model of supermassive black hole seed formation provides an attractive solution to the origin of the quasars now routinely observed at $z \\gtrsim 6$. We use the adaptive mesh refinement code Enzo to simulate the collapse of gas at high redshift, including a nine species chemical model of H, He, and H$_2$. The direct collapse model requires that the gas cools predominantly via atomic hydrogen. To this end we simulate the effect of an anisotropic radiation source on the collapse of a halo at high redshift. The radiation source is placed at a distance of 3 kpc (physical) from the collapsing object. The source is set to emit monochromatically in the center of the Lyman-Werner (LW) band only at $12.8 \\ \\rm{eV}$. The LW radiation emitted from the high redshift source is followed self-consistently using ray tracing techniques. We find that, due to self-shielding, a small amount of H$_2$ is able to form at the very center of the collapsing halo even under very strong LW radiation. Furthermore, we find that a radiation source, emitting $> 10^{54}\\ (\\sim10^3\\ \\rm{J_{21}})$ photons per second is required to cause the collapse of a clump of $\\rm{M \\sim 10^5}$ M$_{\\odot}$. The resulting accretion rate onto the collapsing object is $\\sim 0.25$ M$_{\\odot}$ $\\rm{yr^{-1}}$. Our results display significant differences, compared to the isotropic radiation field case, in terms of H$_2$ fraction at an equivalent radius. These differences will significantly effect the dynamics of the collapse. With the inclusion of a strong anisotropic radiation source, the final mass of the collapsing object is found to be $\\rm{M \\sim 10^5}$ M$_{\\odot}$. This is consistent with predictions for the formation of a supermassive star or quasi-star leading to a supermassive black hole.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-07-16T20:00:28.000Z",
      "comment": "17 pages, Submitted to ApJ. High resolution movies available at http://www.helsinki.fi/~regan/visualisations.html",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2014-09-17T12:07:20.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "massive black hole",
      "anisotropic lyman-werner source",
      "mesh refinement code enzo",
      "black hole seed formation",
      "direct collapse model"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/795/2/137",
      "journal": "The Astrophysical Journal",
      "year": 2014,
      "month": "Nov",
      "volume": 795,
      "number": 2,
      "pages": 137
    },
    "note": {
      "typesetting": "TeX",
      "pages": 18,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1306720,
      "adsabs": "2014ApJ...795..137R"
    }
  }
}