X-ray spectra of accretion discs with dynamic coronae

Julien Malzac; Andrei M. Beloborodov; Juri Poutanen

doi:10.1046/j.1365-8711.2001.04450.x

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arXiv · astro-ph/0102490

X-ray spectra of accretion discs with dynamic coronae

Julien Malzac·Andrei M. Beloborodov·Juri Poutanen

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Abstract

We compute the X-ray spectra produced by non-static coronae atop accretion discs around black holes and neutron stars. The hot corona is radiatively coupled to the underlying disc (the reflector) and generates an X-ray spectrum which is sensitive to the bulk velocity of the coronal plasma, beta=v/c. We show that an outflowing corona reproduces the hard-state spectrum of Cyg X-1 and similar objects. The dynamic model predicts a correlation between the observed amplitude of reflection R and the X-ray spectrum slope Gamma since both strongly depend on beta. A similar correlation was observed and its shape is well fitted by the dynamic model. The scattering of soft radiation in an outflowing corona can also account for the observed optical-UV polarization pattern in active galactic nuclei.

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Julien Malzac, Andrei M. Beloborodov, Juri Poutanen. 2001-02-28. X-ray spectra of accretion discs with dynamic coronae. https://doi.org/10.1046/j.1365-8711.2001.04450.x

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