Spectra of the ¹²CO R(0), P(1), and P(2) transition lines resulting from the addition of all the observed IR source spectra. The light blue rectangles show the positions of the lines at v_LSR ~ − 40, −60, −85, and − 145km s⁻¹ present in all the spectra and that we attribute to foreground clouds. The magenta, blue, and green rectangles show the positions of the lines at velocities v_LSR ~ −185, −130, and +50 kms⁻¹, respectively. They are present in two of the transition line spectra (R(0) and P(1) in the case of the lines at v_LSR ~ −130 and −185 km s⁻¹, and R(0) and P(2) in the case of the line at v_LSR ~ 50 km s⁻¹).