Left column: close up of the central region of B59, where the colour scale and contours are the ¹²CO integrated intensity map (top), the visual extinction map (centre) and the C¹⁸O linewidth map (bottom). The regions used to estimate the average profiles (shown in the centre and right columns) across Flow 1 are shown as blue and green boxes. The dashed lines show the position of the peak of ¹²CO integrated intensity as averaged within each box. Centre and right columns: average profiles of ¹²CO integrated intensity (top row panels), visual extinction (central row panels), and C¹⁸O linewidth (FWHM, bottom row panels). Each column corresponds to a different averaging box, colour-coded as in the left column. The dashed lines and gray-shadowed areas mark the peak and extent of the ¹²CO profile as seen on the first row panels, respectively. The colour-coded shaded areas show the 1-sigma dispersion of each quantity.