Herschel column density map of the northern and southern streamers of IC 5146 with the network of filaments highlighted in blue (adapted from Fig. 3b of Arzoumanian et al. 2011). The positions of the observed spectra are plotted as red squares and blue triangles for N₂H⁺ and C¹⁸O, respectively (the corresponding spectra of the positions observed for filament 2 and filament 14 are shown in Fig. 2). The yellow rectangle shows the subcritical filament 14 which was mapped in C¹⁸O(2−1) and ¹³CO(2−1); cf. Fig. 3.