From top to bottom, in the GRS+UMSB, integrated intensity maps of total ¹²CO emission (noise + detection), of the “detected” ¹²CO emission, of the “noise” in the ¹²CO cube, of the total ¹³CO emission, of the detected ¹³CO emission, of the noise in the ¹³CO cube, and of the diffuse (¹²CO-bright and ¹³CO-dark) and dense (¹²CO-bright and ¹³CO-bright) ¹²CO components.