Left panel: ¹²CO (J = 1−0) emission map (gray scale) overlaid with C¹⁸O (J = 1−0) emission contours (red). The gray levels range from 11.0 (5σ) to 77.0 in steps of 11.0 K km s^-1, while the red contour levels range from 3.0 (5σ) to 4.8 in steps of 0.6 K km s^-1. Right panel: ¹³CO (J = 1−0) integrated emission map. The gray levels range from 3.0 (5σ) to 24.0 in steps of 4.2 K km s^-1. In both maps, the emission has been integrated from 52 to 64 km s^-1. The dashed box indicates our studied filament. The white dashed lines indicate the direction of position-velocity diagrams (see Fig. 9). The beam size is shown in the lower-left corner. The scale units in each panel of both axes are in degrees.