XMM-Newton PN spectra (black), overlaid by two spectral models (diskbb+powerlaw in orange, bremsstrahlung+powerlaw in blue). Dashed lines represent the power law model, while dotted lines show the thermal component and solid lines are the sum of the two. Panel A shows the early time (high/soft state) spectrum, dominated by a thermal component providing 90-95 % of the total flux; panel B shows the late time (low/hard state) spectrum, dominated by a power law component providing 60-65 % of the total flux. The bottom panels show the ratio between the best fit model and the data.