Schematic picture of the definition of velocity components associated with the B211/B213 filament. The spectrum in each panel is the ¹³CO (1–0) spectrum averaged over a 15′ × 15′ area with a center position indicated in the top-left corner. The velocity components with a velocity of <4.0 km s⁻¹ or >7.0 km s⁻¹ are regarded as components not associated with the B211/B213 filament. These components are subtracted from the data cube.