3 starburst galaxies 12C/13C ALMA datacubes

The ^12^C/^13^C isotopic ratios derived from the ratios of these lines range from 30 to 67 with an average of 41.6+/-0.2 in NGC253, from 24 to 62 with an average of 38.3+/-0.4 in NGC1068, and from 6 to 44 with an average of 16.9+/-0.3 in NGC4945.

The highest ^12^C/^13^C isotopic ratios are determined in some of the outskirts of the nuclear regions of the three starburst galaxies. The lowest ratios are associated with the northeastern and southwestern molecular peaks of NGC253, the northeastern and southwestern edge of the mapped region in NGC1068, and the very center of NGC4945. In the case of NGC 1068, the measured ratios suggest inflow from the outer part of NGC1068 into the circum-nuclear disk through both the halo and the bar.