Comparison between the low- and high-P PDR models(P∕k_B, G_UV, and Ω on the top, middle, and bottom panels). In each plot, the low-P models we constrained using the fine-structure lines and FIR luminosity (Sect. 5.1.3) are indicated by the blue solid lines, while the high-P models for the CO lines are presented as the red bars (ranging from the minimum to maximum values). In the G_UV plot, G_stars in Fig. 7 is also shown as the purple dashed lines. In total, eight pixels where we found reasonably good high-P models are shown in each plot, and the location of each pixel can be inferred from Figs. 3 and 5. Finally, we note that the P and Ω plots have broken y-axes to show a wide range of the data.