Two examples of filamentary structures with asymmetric transverse profiles. For both filaments, we show on the left an enlargement of the column density map over which is plotted the crest of the filament, and on the right the averaged column density profile measured perpendicular to the crest. Filament 1 corresponds to the bow-like edge of B59, while Filament 2 corresponds to a filament located in the Stem of the Pipe complex (see dark blue filaments in Fig. 1). The blue and yellow shaded areas show the regions that have been integrated to quantify the observed asymmetry. The Gaussian fits performed to infer the FWHM widths of the two filaments are shown as red solid lines.