Blue circles, green squares, and red triangles indicate the observed PSDs at λ = 1300 Å, 2300 Å, 4000 Å, respectively, for all combinations of BH mass and accretion rate we considered. Solid blue lines, dashed green lines, and dash-dotted red lines indicate the best-fit models for α^* = 0, in the case in which the corona is powered by the accretion process (note that, for clarity reasons, the ranges of the axes are different in each plot). Error bars indicate the combined error of the data and model. The best-fit residuals (i.e. (data-model)/error) are shown in the bottom panel of each plot (see the top panel of Fig. A.1 for the residuals at all wavelengths).