Mapping the inner regions of MCG-6-30-15 withXMM-Newton

Abstract

Timing analysis of a ~95 ks long XMM-Newton observation of the Seyfert 1 galaxy MCG-6-30-15 is presented. Model-independent tools have been used with the intent of resolving the different components that produce the observed flux and spectral variations down to timescales as short as ~300 s. We find that the fractional variability is possibly due to a variable power law component in the hard band, and a slower thermal component at softer energies, but the data do not rule out effects due to the warm absorber. The most relevant result of this work is the first detection of a significant enhancement of the fractional variability in the ~4.7-5.8 keV energy band compared to the underlying continuum. This represents one of the strongest, model-independent, pieces of evidence to date for the presence of redshifted relativistic matter accreting into the black hole. During the brightest flare of the observation, a soft-to-hard time lag of ~600 s is measured. A very significant increase of the iron line intensity is observed ~3000 s after this flare. In the framework of a disk-corona model and assuming the soft-to-hard time lag is due to Comptonization, these findings make it possible to estimate the electron density and the dimensions of the flare region and the disk-flare distance.