A two-zone model for the broad iron line emission in MCG-6-30-15

Abstract

We reanalyze the ASCA and BeppoSAX data of MCG-6-30-15, using a double zone model for the Iron line profile. In this model, the X-ray source is located around $\approx 10$ Schwarzschild radius and the regions interior and exterior to the X-ray source produce the line emission. We find that this model fits the data with similar reduced $\chi^2$ as the standard single zone model. The best fit inclination angle of the source ($i \approx 10^o$) for the medium intensity ASCA data set is compatible with that determined by earlier modeling of optical lines. The observed variability of the line profile with intensity can be explained as variations of the X-ray source size. That several AGN with broad lines have the peak centroid near 6.4 keV can be explained within the framework of this model under certain conditions. We also show that the simultaneous broad band observations of this source by BeppoSAX rules out the Comptonization model which was an alternative to the standard inner disk one. We thereby strengthen the case that the line broadening occurs due to the strong gravitational influence of a Black Hole.