Testing models of X-ray reflection from irradiated discs |
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| Authors: | C Done S Nayakshin |
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| Institution: | 1Department of Physics, University of Durham, South Road, Durham DH1 3LE;2USRA and LHEA, NASA/Goddard Space Flight Center, Greenbelt, MD 20771, USA;3Max-Planck-Institut fur Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching, Germany |
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| Abstract: | We model the reflected spectrum expected from localized magnetic flares above an ionized accretion disc. We concentrate on the case of very luminous magnetic flares above a standard accretion disc extending down to the last stable orbit, and use a simple parametrization to allow for an X-ray-driven wind. Full disc spectra including relativistic smearing are calculated. When fitted with the constant-density reflection models, these spectra give both a low reflected fraction and a small linewidth as seen in the hard spectra from galactic black hole binaries and active galactic nuclei. We fit our calculated spectra to real data from the low/hard state of Nova Muscae and Cyg X-1 and show that these models give comparable χ 2 to those obtained from the constant-density reflection models, which implied a truncated disc. This explicitly demonstrates that the data are consistent either with magnetic flares above an ionized disc extending down to the last stable orbit around a black hole, or with non-ionized, truncated discs. |
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| Keywords: | accretion accretion discs line: formation radiation mechanisms: non-thermal radiative transfer X-rays: general |
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