CO(2–1) integrated intensity map computed from the unmasked data from –285 to 410 km/s for NGC 1097. The APEX contours are plotted from the masked integrated intensity map in 8 log-spaced levels from 0.15 Jy km/s to 75.6 Jy km/s. The red contours show the integrated intensity map of the ALMA CO(2–1) data from Leroy et al. (2021a). The 4 contours are plotted on log-spaced intervals, starting at 1.9 Jy/beam km/s to 24.7 Jy/beam km/s. The dashed green circle marks the 35″ (2.3 kpc) radius aperture around the starburst ring. The beam size of the APEX and ALMA observations is shown in the bottom left.