Gierliński, M. and Maciołek-Niedźwiecki, A. and Ebisawa, K. (2001) 'Application of a relativistic accretion disc model to X-ray spectra of LMC X-1 and GRO J1655-40.', Monthly notices of the Royal Astronomical Society., 325 (3). pp. 1253-1265.
We present a general relativistic accretion disc model and its application to the soft-state X-ray spectra of black hole binaries. The model assumes a flat, optically thick disc around a rotating Kerr black hole. The disc locally radiates away the dissipated energy as a blackbody. Special and general relativistic effects influencing photons emitted by the disc are taken into account. The emerging spectrum, as seen by a distant observer, is parametrized by the black hole mass and spin, the accretion rate, the disc inclination angle and the inner disc radius. We fit the ASCA soft-state X-ray spectra of LMC X-1 and GRO J1655-40 by this model. We find that, having additional limits on the black hole mass and inclination angle from optical/UV observations, we can constrain the black hole spin from X-ray data. In LMC X-1 the constraint is weak, and we can only rule out the maximally rotating black hole. In GRO J1655-40 we can limit the spin much better, and we find 0.68a0.88. Accretion discs in both sources are radiation-pressure dominated. We do not find Compton reflection features in the spectra of any of these objects.
|Keywords:||Accretion discs, Relativity, Stars.|
|Full text:||PDF - Other (416Kb)|
|Publisher Web site:||http://dx.doi.org/10.1046/j.1365-8711.2001.04540.x|
|Publisher statement:||The definitive version is available at www.blackwell-synergy.com|
|Record Created:||28 Apr 2008|
|Last Modified:||04 Aug 2011 14:48|
|Social bookmarking:||Export: EndNote, Zotero | BibTex|
|Usage statistics||Look up in GoogleScholar | Find in a UK Library|