Left panel: ¹²CO (1–0) and ¹³CO (1–0) emission observed toward the B211/B213 filament. Right panel: schematic picture of the velocity components. The ¹² CO and ¹³ CO data are from Goldsmith et al. (2008). The left panel is adopted from Palmeirim et al. (2013). In the left panel the red color shows the distribution of the ¹² CO (1–0) emission with a velocity range of 6.6–7.4 km s⁻¹, the green color shows ¹³CO (1–0) emission with a velocity range of 5.6–6.4 km s⁻¹, and the blue color shows ¹²CO (1–0) emission with a velocity range of 4.2–5.5 km s⁻¹. The white box perpendicular to the filament axis shows the cut line for the position velocity diagrams shown in Fig. 6.