Fig. 3. The left column shows the number of detected sources divided by the sampled area, as a function of R, for the northern () Galaxy (top row), the southern () Galaxy (medium row), and the whole Galaxy (bottom row). The center column shows, in the same order, the azimuthally averaged face-on FIR galactic surface luminosity produced by embedded massive stars; the right column shows the azimuthally averaged FIR luminosity per embedded massive star forming region. The solid line corresponds to the complete dataset. The dashed line represents the dataset corrected for incompleteness of the sample, as described in Sect. 3.5