Velocity structures in Per-emb-2. Left: Integrated-intensity map of CCS (from 6.0 to 8.0 km s⁻¹) in colour overlaid with the Herschel column density map in contours (as in Fig. 1) and the position of the velocity cut along the bridge (in white). Right: Position-velocity plots along the bridge structure from the cut along the bridge seen on the left. White and red stars indicate the positions of starless cores and the protostellar core. The yellow cross indicates the position of the CCS peak. The blue ellipse is the map effective beam size.