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Spectral variations of LMC X-3 observed with GINGA

1993; IOP Publishing; Volume: 403; Linguagem: Inglês

10.1086/172239

1538-4357

K. Ebisawa, Fumiyoshi Makino, Kazuhisa Mitsuda, T. Belloni, A. P. Cowley, P. C. Schmidtke, A. Treves,

Astronomical Observations and Instrumentation

view Abstract Citations (92) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Spectral Variations of LMC X-3 Observed with GINGA Ebisawa, Ken ; Makino, Fumiyoshi ; Mitsuda, Kazuhisa ; Belloni, Tomaso ; Cowley, Anne P. ; Schmidtke, Paul C. ; Treves, Aldo Abstract The prime black hole candidate LMC X-3 was observed over 3 yr with the Ginga satellite, and a characteristic spectral variation was found accompanying the periodic intensity variation of ~198 (or possibly ~99) days (Cowley et al. 1991). The energy spectrum of LMC X-3 consists of the soft, thermal component and the hard, power-law component, which are respectively dominant below and above ~9 keV. The soft component, which carries most of the X-ray intensity, shows a clear correlation between the intensity and the hardness, while the hard component varies independently of the soft component. It was found that the spectral variation of the soft component is well described by an optically thick accretion disk model with a remarkably constant innermost radius and variable mass accretion rate. The constancy of the innermost radius suggests it is related to the mass of the central object. Supposing that the innermost radius of the accretion disk is the last stable orbit around a black hole, i.e., 3 times the Schwarzschild radius, we estimate the mass of the central object in LMC X-3. Satisfactory agreement has been found between the mass thus derived and the fiducial mass lower limit determined from observations of the binary motion. Publication: The Astrophysical Journal Pub Date: February 1993 DOI: 10.1086/172239 Bibcode: 1993ApJ...403..684E Keywords: Accretion Disks; Black Holes (Astronomy); Ginga Satellite; Magellanic Clouds; Spaceborne Astronomy; X Ray Sources; Astronomical Models; Astronomical Spectroscopy; Energy Spectra; Astrophysics; X-RAYS: STARS full text sources ADS | data products SIMBAD (1) NED (1)