The source-averaged ¹³CO-intensity-weighted Mach number, ﹩{\langle { \mathcal M }\rangle }_{{}^{13}{\rm{CO}}}﹩, vs. the dust-derived H₂ column density, ﹩{N}_{{{\rm{H}}}_{2}-{\rm{dust}}}﹩ (a), and the catalog dust temperature, T_dust (b). Panel (c) shows T_dust vs. ﹩{N}_{{{\rm{H}}}_{2}-{\rm{dust}}}﹩ for the same sample. Black points represent individual PGCCs, red symbols indicate median values in logarithmic bins, and error bars show the corresponding median absolute deviations. Gray and blue contours trace the kernel-density distribution.