Marginalised (1D – diagonal panel, and 2D – bottom left panel) posterior distributions of the number density and kinetic temperature in CO-bearing gas towards SK −67 2 (grey), SK −68 137 (red), and SK 143 (purple). The shaded regions depict 0.683 (1D and 2D) and 0.954 (2D) credible intervals. The solid, dashed, and dotted lines represent constant thermal pressures of 10⁴, 10⁵, and 10⁶ cm⁻³ K, respectively.