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Spectral and temporal properties of the black hole candidate systemsObservations of Galactic, and extragalactic black hole candidates show that their spectra can be fitted by the thermal Comptonization spectra in the hard state and two components in the soft state. The first component is a black body shape spectrum and the second component is an extended power law with a spectral index of between 1 and 2. The spectral formation of Comptonized spectra in the presence of thermal and bulk motion is considered. In the soft state, when the disk luminosity is high, the emission region temperature is low. In the limit of low plasma temperature, the theoretical spectrum consists of two components: the soft input photons escaping without significant energy change, and a power law that extends to high energies. The spectral index is in the range between 1 and 2, depending on the mass accretion rate. The extended power law is the result of upscattering of soft disk photons in the bulk flow which takes place in the vicinity of the black hole. In the hard state, the disk luminosity is low, the electron temperature of the emission region is high and the thermal Comptonization is the dominant process in the formation of the resulting spectrum.
Document ID
19970025754
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Titarchuk, Lev
(NASA Goddard Space Flight Center Greenbelt, MD United States)
Date Acquired
August 17, 2013
Publication Date
March 1, 1997
Publication Information
Publication: Proceedings of 2nd INTEGRAL Workshop 'The Transparent Universe'
Subject Category
Astronomy
Accession Number
97N25224
Funding Number(s)
CONTRACT_GRANT: NCC5-52
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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