Middle panel: line integrated ¹²CO 3→2 emission (between 26 and 35 km s^-1) of G11-0.12. The dust column density from Herschel is overlaid as black contours (levels 3,4,5,6 × 10²² cm^-2). The numbering from 1 to 4 indicates the position of submm-continuum sources detected with ATLASGAL and subsequently observed in N₂H⁺ (Tackenberg et al. 2014). The ¹²CO 3→2 spectra at these positions are displayed in the panels. The blue-dashed line denotes the centre velocity of the N₂H⁺ line.