X-rays from active galactic nuclei: relativistically broadened emission lines.
The X-ray spectra of many Seyfert 1 galaxies show an iron-K emission line. Some of these lines are broad and skew, reflecting the rapid motion of the accreting gas together with the deep gravitational potential of the central black hole. The observational evidence for broad iron lines is reviewed, from ASCA to recent Chandra and XMM-Newton spectra. Examples are shown from MCG-6-30-15, for which line variability is discussed. Current results indicate that we are studying accretion flows well within 6GM/c(2).
Fabian
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AC
Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK.