CH, H I, ¹³CO Gaussian-fitted velocity along the west ridge of the cloud. Each position is quoted as in Fig. 1, blue diamonds. The first two ¹³CO peak velocities are shown in thin line because here the S/N is too low to trust the Gaussian fit. We converted angular distance into physical distance using the cloud distance of 93 pc (see Zucker et al. 2019). In CH, a linear correlation was found (red dotted line).