Power spectrum of the PACS 100 μm map, at degraded resolutions of 11 and 18′′. The vertical dashed line to the right represents the smoothed spatial resolution on the major axis. Since the deprojection to a face-on galaxy implies a factor 1   ! cos(56°) = 1.79 larger beam on the minor axis, we have also plotted a second dashed vertical line to the left, indicating the geometric mean of the resolution on both the minor and major axes.