8th HEAD Meeting, 8-11 September, 2004
Session 13 ``Beyond Einstein" Science
Oral, Thursday, September 9, 2004, 9:00-10:21am

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[13.02] Evidence for gravitational light bending in the X-ray properties of AGNs and GBHCs

G. Miniutti, A.C. Fabian (Institute of Astronomy, University of Cambridge)

We discuss the spectral and temporal properties of the active galaxies MCG-6-30-15 and NGC 3516, and of the Galactic black hole candidate XTE J1650-500 as obtained from X-ray observations. The variability of the reflection component and of the associated iron line in these sources challenges the standard picture of reflection models. The reflection component is found to remain almost constant despite large variation in the continuum, as opposed to the expectation of a correlated variability of the two components. The presence of a broad iron line in all sources makes it difficult to invoke a distant reflector to account for the lack of reflection (and broad iron line) variability. We show that the X-ray data are consistent with our recently proposed model for the spectral variability of accreting X-ray sources which invokes strong gravitational light bending in the vicinity of the central black hole, and that the model accounts for many of the otherwise puzzling observed X-ray properties. We also show that the same model can explain the spectral variability of the NLS1 1H0707-495 revealed by XMM-Newton observations.

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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.