{
  "id": "1003.0283",
  "version": "v1",
  "published": "2010-03-01T09:09:28.000Z",
  "updated": "2010-03-01T09:09:28.000Z",
  "title": "Identification of the X-Ray Thermal Dominant State in an Ultraluminous X-Ray Source in M82",
  "authors": [
    "Hua Feng",
    "Philip Kaaret"
  ],
  "comment": "accepted for publication in the Astrophysical Journal Letters",
  "journal": "Astrophys. J. 712: L169-L173, 2010",
  "doi": "10.1088/2041-8205/712/2/L169",
  "categories": [
    "astro-ph.HE"
  ],
  "abstract": "The thermal dominant state in black hole binaries (BHBs) is well understood but rarely seen in ultraluminous X-ray sources (ULXs). Using simultaneous observations of M82 with Chandra and XMM-Newton, we report the first likely identification of the thermal dominant state in a ULX based on the disappearance of X-ray oscillations, low timing noise, and a spectrum dominated by multicolor disk emission with luminosity varying to the 4th power of the disk temperature. This indicates that ULXs are similar to Galactic BHBs. The brightest X-ray spectrum can be fitted with a relativistic disk model with either a highly super-Eddington (L_disk/L_Edd = 160) non-rotating black hole or a close to Eddington (L_disk/L_Edd ~ 2) rapidly rotating black hole. The latter interpretation is preferred, due to the absence of such highly super-Eddington states in Galactic black holes and active galactic nuclei, and suggests that the ULX in M82 contains a black hole of 200-800 solar masses with nearly maximal spin. On long timescales, the source normally stays at a relatively low flux level with a regular 62-day orbital modulation and occasionally exhibits irregular flaring activity. The thermal dominant states are all found during outbursts.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2010-03-01T09:09:28.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "x-ray thermal dominant state",
      "ultraluminous x-ray source",
      "identification",
      "relatively low flux level",
      "galactic black holes"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "journal": "The Astrophysical Journal",
      "year": 2010,
      "month": "Apr",
      "volume": 712,
      "number": 2
    },
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2010ApJ...712L.169F",
      "inspire": 847114
    }
  }
}