Flux ratio per pixel of the 1332keV line from ⁶⁰Fe versus the 1809keV line from ²⁶Al. Left: case 1. Right: case 2. It is seen that the hot spots from ²⁶Al in Fig. 7 are turned into cold spots in these flux ratio maps. The reason is again the 3.8 longer lifetime of ⁶⁰Fe which lets the γ-ray emission of this isotope appear more homogeneous. We note the scales of the flux ratio maps: in case 1, the contrast is particularly small, whereas in case 2, the strong accumulation in of ⁶⁰Fe already-mixed in the bubble walls increases the contrast up to a factor of 10.