Color map of the intensity of the CH₃CN J_K = 14₂–13₂ line (E_u = 121 K) at a differentV_LSR (km s⁻¹), indicated in the upper-left corner of each panel. The color-intensity scale is shown on the right. The grayscale-filled and white contours show the JVLA 22-GHz and 13-GHz continuum, respectively, plotting the same levels as in Fig. 4. The green contours reproduce the ALMA 1.2-mm continuum, showing levels at 10, 20, 40, and 80% of the peak emission of 0.032 Jy beam⁻¹. The magenta-edged white triangles mark the positions of the 22-GHz water masers derived through VLBI observations by Sanna et al. (2010). Upper first and second panels: high-mass YSO Bm, and the compact molecular source B-NW are labeled.