RGB image as in Fig. 2. The solid white annuli are the four source regions around Wd 1 used for the study of HESS J1646−458, while the dashed white regions are the corresponding background regions. The yellow circle around GX 340+0 was masked for the analysis of the three innermost annulus pairs. For the analysis of the outermost annulus pair, the mask was larger and had a radius of 30 ′.