Mean deconvolved width (FWHM) versus mean central column density for the 27 filaments of IC 5146 shown in Fig. 3b, along with 32 filaments in Aquila and 31 filaments in Polaris, all analyzed in the same way (see Sect. 3). The spatial resolutions of the column density maps used in the analysis for the three regions are marked by the horizontal dotted lines. The filament width has a typical value of  ~0.1 pc, regardless of central column density. The solid line running from top left to bottom right shows the central (thermal) Jeans length as a function of central column density [] for a gas temperature of 10 K.