Map of rotation temperature (T_rot, left panel) and NH₃ total column density (N(NH₃), right panel) derived from the NH₃ (2, 2)-to-(1, 1) ratio as described in Sect. 3.3.1. In left panel, contour levels (dotted lines) range from 11 K to 20 K in steps of 3 K, while they range from 4  ×  10¹⁴ cm^-2 to 3.2  ×  10¹⁵ cm^-2 in steps of 4  ×  10¹⁴ cm^-2 in the right panel. Crosses and solid contours indicate the millimetre continuum cores and the N₂D⁺ cores, respectively, as in Figs. 1 and 3. In both panels, the ellipse in the bottom left corner shows the VLA synthesised beam.