{
  "id": "1206.2350",
  "version": "v3",
  "published": "2012-06-11T20:00:00.000Z",
  "updated": "2015-04-06T00:20:14.000Z",
  "title": "Hydrodynamical Simulations to Determine the Feeding Rate of Black Holes by the Tidal Disruption of Stars: The Importance of the Impact Parameter and Stellar Structure",
  "authors": [
    "James Guillochon",
    "Enrico Ramirez-Ruiz"
  ],
  "comment": "16 pages, 13 figures (2 new figures in revised version). Published in ApJ. Latest version incorporates erratum that fixes issue with fitting formulae not including enough significant digits",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "The disruption of stars by supermassive black holes has been linked to more than a dozen flares in the cores of galaxies out to redshift $z \\sim 0.4$. Modeling these flares properly requires a prediction of the rate of mass return to the black hole after a disruption. Through hydrodynamical simulation, we show that aside from the full disruption of a solar mass star at the exact limit where the star is destroyed, the common assumptions used to estimate $\\dot{M}(t)$, the rate of mass return to the black hole, are largely invalid. While the analytical approximation to tidal disruption predicts that the least-centrally concentrated stars and the deepest encounters should have more quickly-peaked flares, we find that the most-centrally concentrated stars have the quickest-peaking flares, and the trend between the time of peak and the impact parameter for deeply-penetrating encounters reverses beyond the critical distance at which the star is completely destroyed. We also show that the most-centrally concentrated stars produced a characteristic drop in $\\dot{M}(t)$ shortly after peak when a star is only partially disrupted, with the power law index $n$ being as extreme as -4 in the months immediately following the peak of a flare. Additionally, we find that $n$ asymptotes to $\\simeq -2.2$ for both low- and high-mass stars for approximately half of all stellar disruptions. Both of these results are significantly steeper than the typically assumed $n = -5/3$. As these precipitous decay rates are only seen for events in which a stellar core survives the disruption, they can be used to determine if an observed tidal disruption flare produced a surviving remnant. These results should be taken into consideration when flares arising from tidal disruptions are modeled. [abridged]",
  "revisions": [
    {
      "version": "v2",
      "updated": "2013-03-01T23:11:28.000Z",
      "comment": "16 pages, 13 figures (2 new figures in revised version). Accepted to ApJ",
      "journal": null,
      "doi": null
    },
    {
      "version": "v3",
      "updated": "2015-04-06T00:20:14.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "tidal disruption",
      "black hole",
      "impact parameter",
      "hydrodynamical simulation",
      "stellar structure"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/798/1/64",
      "journal": "The Astrophysical Journal",
      "year": 2013,
      "month": "Apr",
      "volume": 767,
      "number": 1,
      "pages": 25
    },
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 1117984,
      "adsabs": "2013ApJ...767...25G"
    }
  }
}