Top: the region where the two-layer fit (method C) is applicable is shown with white diamonds on the integrated brightness temperature map of the NH₃(1,1) satellites. Blue plus signs indicate positions where T_ex,bg> 11 K, i.e., where the excitation temperature of the background component exceeds the average kinetic temperature of the core. Bottom: comparison between the NH₃(1,1) column densities derived by fits to the hyperfine satellites only (method B, x-axis) and two-layer fits (method C, y-axis). The average uncertainties of the points are indicated in the top left corner. The red line represents the one-to-one correlation.