Results of the rotation diagram analysis assuming optically thin emission. Maps of methyl cyanide rotational temperature (T_rot, colour scale) and total beam-averaged column density (N_tot, overlaid contours) across the Orion KL region. Both quantities are determined from rotation diagram analyses of the J = 6_K−5_K, J = 12_K−11_K, J = 13_K−12_K, and J = 14_K−13_K line emission at each map position, neglecting the effects of line opacity and beam dilution (see Sect. 4.2 for details). Column density contours are plotted at 0.5 × 10¹⁵ cm^-2 intervals, starting at 1.0 × 10¹⁵ cm^-2 (black lines). The various sources indicated are as described in Fig. 1, with the approximate location and extent of the hot zone seen to the northeast of IRc2 also marked by a red circle in each panel (defined in Sect. 5).