Contour plots at 99, 90, and 68% confidence obtained using a model composed of a primary power-law absorbed by a cold column and by an edge at E ~ 7.5 keV plus a Gaussian in emission (model 3 in Table 1). From left to right: (upper left panel) photoindex Γ vs. absorbing column density (N_H in units of 10²²); (upper right panel) optical depth of the edge (τ) vs. its energy centroid; (lower left panel) Gaussian emission line normalization vs. its energy. In this case, only 90 and 68% confidence contours are presented since the emission Gaussian line is detected with ~97% confidence in this model and the 99% confidence contour gives only an upper limit; (lower right panel) data-to-model ratio expressed in terms of standard deviations. Binning and colors as in Fig. 1.