Disk-Corona Interactions in Soft Spectral States of Black Hole Binaries
Re-analysis of some archival X-ray data of black hole binaries in soft spectral states is presented. Results of detailed spectral fitting, including proper physical description of the X-ray reprocessed component, indicate that in most cases the soft, thermal disk emission cannot be described by a simple multi-color blackbody model. Additional Comptonization of those seed photons provides an acceptable description of the soft component, implying a presence of a warm (kT e ∼ 1 keV), mildly optically thick (τ ∼ 10) phase of accreting plasma.
Combined spectral/temporal analysis of GRS 1124-68 during ‘flip-flop’ transitions in very high state suggests that the optically thick accretion flow can proceed in (at least) two modes giving the same time-integrated behaviour (i.e. energy spectra) but very different timing behaviour.
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