Completeness level of the clumps extraction as a function of the clump mass (panel a) and of the contrast of the clump column density over its local background (panel b). The 90% completeness level is indicated with a dashed horizontal line. Panel a: the clump sample is 90% complete above 1.7 M_⊙. Panel b: thehistogram has been constructed with a constant number of 80 synthetic sources in the 11 first bins, plus a bin containing the remaining 290 sources that have all been detected. The red curve connects the median contrast value in each bin. Of the clumps, 90% are detected for a contrast larger than 1.1.