Morphological features of Vela. The upper left panel displays the false-color image of Vela shown in Fig. 1, with white boxes outlining the regions depicted by each of the other panels, which are identified with the corresponding letter. The brightness scale used in each subpanel preserves the relative colors of the original image, via a truncation of the original brightness scale at equal quantiles for the soft, medium, and hard bands, with the goal of optimally displaying the morphology of the features. In each panel, we indicate the regions used for extraction of the spectra shown in Fig. 8 in white, with numbers distinguishing the individual spectra in case of multiple regions.