Top panel: 4 − 10 keV spectral residuals of the 2009 Long Look pn data, relative to the simple power-law model (top panel) and to model A (bottom panel). The two arrows mark strong negative residuals that are present in both cases. Data have been rebinned to 3σ significance. Bottom panel: 99% confidence contours for the rest frame normalizations and centroid energy of the absorption lines used to model the residuals; the black contours refer to the addition of the absorption lines to the simple power-law model, while the red ones to the addition to model A. The four vertical green lines mark the theoretical energies of the strongest transitions of Fe XXV and Fe XXVI, while the two dotted blue lines mark the position of the Fe XXV Heα and Fe XXVI Lyα transitions, both blueshifted by υ_out = 0.055   c.