Left panel: optical depth map of 250 μm derived from the Herschel observations, the white plus signs indicate starless cores and the cyan crosses indicate protostellar source candidates identified by Montillaud et al. (2015); and right panel: clumps (labelled A to F) chosen for the spectral analysis (Figs. 14 and 15). The labels L1 and L2 indicate the positions where we have extracted spectra to analyse the warm filament (Fig. D.1). The white outline in the panels corresponds to the area of the Nobeyama observations. The cyan ellipse marks the selected striation S1, and the red rectangle marks the area used for the background subtraction as discussed in Sect. 3.4.