{
  "id": "0911.1151",
  "version": "v1",
  "published": "2009-11-06T00:23:50.000Z",
  "updated": "2009-11-06T00:23:50.000Z",
  "title": "Black hole accretion disks in the canonical low-hard state",
  "authors": [
    "R. C. Reis",
    "A. C. Fabian",
    "J. M. Miller"
  ],
  "comment": "Accepted for publication in MNRAS, 20 pages, 18 figures",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "Stellar-mass black holes in the low-hard state may hold clues to jet formation and basic accretion disk physics, but the nature of the accretion flow remains uncertain. A standard thin disk can extend close to the innermost stable circular orbit, but the inner disk may evaporate when the mass accretion rate is reduced. Blackbody-like continuum emission and dynamically-broadened iron emission lines provide independent means of probing the radial extent of the inner disk. Here, we present an X-ray study of eight black holes in the low-hard state. A thermal disk continuum with a colour temperature consistent with $L \\propto T^{4}$ is clearly detected in all eight sources, down to $\\approx5\\times10^{-4}L_{Edd}$. In six sources, disk models exclude a truncation radius larger than 10rg. Iron-ka fluorescence line emission is observed in half of the sample, down to luminosities of $\\approx1.5\\times10^{-3}L_{Edd}$. Detailed fits to the line profiles exclude a truncated disk in each case. If strong evidence of truncation is defined as (1) a non-detection of a broad iron line, {\\it and} (2) an inner disk temperature much cooler than expected from the ${\\rm L} \\propto {\\rm T}^{4}$ relation, none of the spectra in this sample offer strong evidence of disk truncation. This suggests that the inner disk may evaporate at or below $\\approx1.5\\times10^{-3}L_{Edd}$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2009-11-06T00:23:50.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "black hole accretion disks",
      "canonical low-hard state",
      "inner disk",
      "basic accretion disk physics",
      "iron-ka fluorescence line emission"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1111/j.1365-2966.2009.15976.x",
      "journal": "Monthly Notices of the Royal Astronomical Society",
      "year": 2010,
      "month": "Feb",
      "volume": 402,
      "number": 2,
      "pages": 836
    },
    "note": {
      "typesetting": "TeX",
      "pages": 20,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "inspire": 836233,
      "adsabs": "2010MNRAS.402..836R"
    }
  }
}