H i emission distribution in the V − l plane. Left panel: radial velocity-latitude H i image averaged in the Galactic longitude range from 120°. 8 to 121°.8. Contour levels are 12, 15, 18, and 21 K. The dashed line indicates the location of the cross-cut shown in the right panel. Right panel: cross-cut at b = −5°. 09 obtained from the left image. The central velocity of GS 121–05–037 is marked as a vertical black line at V = −37 km s⁻¹.