Maps of the line integrated intensity, , observed toward the ℓ = 224° region in the various CO isotopologues. From left to right and from top to bottom: ¹²CO(1−0), ¹³CO(1−0), C¹⁸O(1−0) and C¹⁷O(1−0). The map of C¹⁷O(1−0) has been convolved to an 80′′ beam and regridded to a 40′′ spacing to increase the S/N. The black boxes represent two of the regions where spectra have been averaged and shown in Fig. 4.