[C I](1−0) (left) and R_C I/CO (right) maps of NGC 1808 in the upper panels and NGC 7469 in the lower panels. Similar to Figs. 1 and 2, the line intensity maps are defined in the broad mask and the R_C I/CO maps are restricted to the combined signal mask. Boxes in the left panels indicate the manually selected central regions where the pixels are highlighted in Fig. 4. Contours in the right panels indicate the 5, 10, 20 and 50-σ levels of the left-panel C I intensity maps.