Left: original HAWK-I J-band image of RCW 36. Centre: HAWK-I J-band image with only the nebular component. Right: HAWK-I J-band image with only the point sources (hereby called denebulised). The white contours trace the regions used in the present analysis; the different contour in chip 3 is due to the artefact described in Section 2. The dotted lines refer to the coordinate grid lines of constant right ascension or declination.