T_mb (K) for the ¹³CO J = 1− 0 line for the distant molecular cloud components, corresponding to velocities between − 27.5 and − 15.0 km s⁻¹. Overlaid arethe radio contours at 1420 MHz in units of brightness temperature at 4.8, 5.0, 5.5, and 6.0 K. The velocities are indicated in the upper left corner of each panel. All figures in the same row share the same colour bar, plotted at the left end of each row.