Top panel: the solid lines show the power-law emission after the passage through two absorbers, one of which is partially covering the source (model B). This model was fit to the average 2009 Long Look (black), Dec. 2008 (green), Jun. 2008 (red), and Dec. 2004 (blue) epoch spectra. The dashed lines represent the direct continuum components that are not absorbed. Bottom panel: average 2009 Long Look (black points), Dec. 2008 (green triangles), Jun. 2008 (red circles), and Dec. 2004 (blue squares) spectral residuals relative to model B; the data have been rebinned for visual purpose only to respectively 15, 5, 5, and 10σ.