Residual significance distribution after taking the HGPS emission model into account (see Fig. 5, middle panel). The significance was computed using a Gaussian source morphology of size σ = 0.05°, 0.10°, and 0.20°. A vertical line at is shown, corresponding to the detection threshold for the HGPS multi-Gaussian modeling. The sky region corresponding to this distribution includes pixels inside exclusion regions, except for the Galactic center and shell-type SNRs, which were not modeled for the HGPS (see Table 1, lower panel of Fig. 5 and Fig. A.6).