Broad Iron Lines in AGN: The Case of MCG--6-30-15

We review the main properties of the broad iron line of the Seyfert galaxy MCG--6-30-15 and present the latest results on its variability based on XMM-Newton observations. On a 10 ks time scale, the iron line appears to be almost constant during a normal flux state (2001 observation) despite changes by more than a factor 3 in the continuum. On the other hand, a correlation between line and continuum is found in 2000, during a low flux state of the source. Rapid line variability is indeed present, consistently with emission from the inner accretion disc region. Observational results are interpreted in terms of a light bending model that can explain what are otherwise puzzling properties of this source and is able to reproduce many of the observed properties.