Left: integrated ¹³CO(2−1) and C¹⁸O(2−1) intensity maps of filament 14 in IC 5146 (cf. Fig. 3). Two ¹³CO(2−1) contours are overlaid: 1.2 and 1.5 K km s^-1. The blue squares and red triangles correspond to the positions along the filament where the line-of-sight velocity dispersion has been measured from the ¹³CO(2−1) and C¹⁸O(2−1) maps respectively. The two black triangles on the C¹⁸O(2−1) map correspond to the positions of the central pixel of the array receiver of HERA observed in a single pointing. The labels indicate the offsets in arcsec relative to the center of the map at Ra(J2000) = 21:47:56 and Dec(J2000) = 48:08:55. The black triangle at position (−94″, −223″) is the point which represents filament 14 in the column density vs. velocity dispersion diagram (black triangle in Fig. 6). Right: total velocity dispersions, σ_tot (see Eq. (3)), measured along the same filament. The x-axis goes from the south to the north of the filament. The red triangle and blue squares correspond to measurements made on the C¹⁸O(2−1) and ¹³CO(2−1) maps, respectively. Individual spectra were constructed by spatially averaging the signal located within 10″ of the central position to increase the signal to noise ratio of the data. The linewidths of the ¹³CO(2−1) spectra were corrected for the broadening due to optical depth effects (see explanations in Sect. 4). The median value of σ_tot is 0.25 km s^-1 with a narrow dispersion of 0.03 km s^-1.