RADEX non-LTE modeling of the line intensity of o- and p-H₂CO to probe the column densities of both species. Each panel corresponds to a slice of constant T_kin from a 3D grid of (see Appendix C). Red contours are for o-H₂CO, while blue ones are for p-H₂CO. The solid and dotted contours are represented by 99.7 and 99.99% that the observed intensity inside the modeled contours (or and 25), respectively.