Illustration of the catalog model construction in the region of 350° to 328° in Galactic longitude. The upper panel shows the γ-ray excess counts smoothed by the PSF, the middle panel the PSF-convolved and smoothed excess model, and the lower panel the significance map of the residuals for a point-like source hypothesis (given in ). The middle panel shows examples of the steps taken in the excess map modeling part of the source catalog procedure (see Sect. 4 for details). It starts by cutting out shell-type supernova remnants (SNRs; RX J1713.7−3946 and the SNR candidate HESS J1614−518 in this region) and by assuming a fixed large-scale emission component. Then a multi-Gaussian model was fitted with the significant components shown in the middle panel as thin transparent circles. Some of these were discarded and are not part of the emission attributed to HGPS catalog sources. White circles show examples of single-component as well as multicomponent sources. For a complete overview of all analysis regions (ROIs) and excluded sources, see Fig. A.6.