Stacked CO spectra over the full galaxy (Left) Stacked spectra over the ¹²CO(1–0) 3σ mask. ¹³CO(1–0) spectrum scaled up by a factor of 5, C¹⁸O(1–0) by a factor of 10. We mark the number of sightlines per mask with n. (Middle) Similar to the left panel, but stacked over the ¹³CO(1–0) 3σ mask. We do not detected significant C¹⁸O(1–0) emission. (Right) moment 0 map of ¹²CO(1–0). The S/N = 3 contour of ¹²CO(1–0) is illustrated by the solid line, while for ¹³CO(1–0) it is indicated by the dashed line.