Upper panel: summed EPIC-pn spectra of the 10 observations performed during the 2009 XMM-Newton monitoring campaign. The data are fit, in the 4–5 and 7.5–10 keV bands, with a simple power law, absorbed by Galactic material, and the ratio of the data to the best-fit model is shown. The dotted lines indicate the rest frame positions of the Fe Kα, Fe Kβ, Fe xxv (resonance, intercombination and forbidden), and Fe xxvi lines. The x-axis reports the observed-frame energy. Lower panel: in red the 2006 XIS0+XIS3 Suzaku summed mean spectra are shown. In black the summed spectra of the 5 XMM-Newton observations performed between 2000 and 2006 are shown. This figure is taken from Ponti et al. (2009). The arrows mark possible absorption features in the spectrum.