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Title: THE SLIM-DISK STATE OF THE ULTRALUMINOUS X-RAY SOURCE IN M83

The transient ULX in M83 that went into outburst in, or shortly before, 2010 is still active. Our new XMM-Newton spectra show that it has a curved spectrum typical of the upper end of the high/soft state or slim-disk state. It appears to be spanning the gap between Galactic stellar-mass black holes (BHs) and the ultraluminous state, at X-ray luminosities of ≈1-3 × 10{sup 39} erg s{sup –1} (a factor of two lower than in the 2010 and 2011 Chandra observations). From its broadened disk-like spectral shape at that luminosity, and from the fitted inner-disk radius and temperature, we argue that the accreting object is an ordinary stellar-mass BH with M ∼ 10-20 M {sub ☉}. We suggest that in the 2010 and 2011 Chandra observations, the source was seen at a higher accretion rate, resulting in a power-law-dominated spectrum with a soft excess at large radii.
Authors:
 [1] ; ;  [2] ;  [3] ;  [4] ;  [5]
  1. International Centre for Radio Astronomy Research, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia)
  2. The Henry A. Rowland Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)
  3. Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)
  4. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  5. Department of Physics, Middlebury College, Middlebury, VT 05753 (United States)
Publication Date:
OSTI Identifier:
22364401
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; BLACK HOLES; COSMIC X-RAY SOURCES; DIAGRAMS; EMISSION SPECTRA; GALAXIES; LUMINOSITY; MASS; TRANSIENTS; X RADIATION