NOEMA data. The color map reproduces the column density (upper panel) and the velocity (lower panel) of the CH₃ CN emission determined by fitting with XCLASS the CH₃CN J_K = 12_K–11_K (K = 0–6) lines (including the CH₃ ¹³CN isotopologs), simultaneously. The plotted regions correspond to the areas in which the 1.37 mm continuum emission is higher than 13 and 16 mJy beam⁻¹ for the column density and velocity plots, respectively. The 1.37 mm continuum emission is represented with black contours, showing six levels increasing logarithmically from 13 to 35 mJy beam⁻¹: the positions of the three strongest 1.37 mm peaks are denoted using the same labels as in Beuther et al. (2018, see Table 5). The restoring beams of the 1.37 mm continuum and CH₃ CN maps are shown in the lower left corner of the upper panel and lower right corner of the lower panel, respectively.