Each panel shows the integrated intensity of the NH₃ (1,1) line (see colour scale at right). The central pointings (see main text) are shown with a black cross. The contours show the integrated intensity of the corresponding (2,2) transition, at levels of 0.3, 0.5, 0.7, 0.9 of the peak value, which is 0.4 K km s⁻¹ (L1544, top panel), 1.6 K km s⁻¹ (IRAS4A, central panel), and 2.3 K km s⁻¹ (L1157-B1, bottom panel). The beam size and scale bar are shown in the bottom left and right corners, respectively, of each panel. The black circles in the top and central panels show the areas where the spectra in Fig. 1 are extracted.