From left to right: N₂H⁺ maps of integrated intensity, velocity centroid, linewidth, and ratio of non-thermal to thermal pressure. Symbols mark the positions of SMM1 (●), MMS (+), and IRS (★). The dashed circle in panel a) represents the FWHM volume density distribution of SMM1. The contours in panels a)–c) represent the N₂H⁺ column density with contours from (1...3) × 10¹³ cm^-2 in steps of 0.5 × 10¹³ cm^-2. In panel d) the contour marks the P_NT/P_T = 0.3 line. The dash-dotted lines in panels b) and c) mark the cut for the position-velocity diagram, which is shown in Fig. 7. The synthesised beam size is indicated in the bottom right corners.