Profiles of mid-IR data along the cut indicated by the yellow arrow in the left panel. While the center of the cut in the right panel is G18.93/m, its upper end is chosen to be towards the potential ionizing sources. The different colored profiles in the right panel are of increasing wavelength, starting with 8  μm at the top going to 870  μm at the bottom. The intensities are not to scale, but adopted to fit in the panel. The green vertical line indicates the position of the ATLASGAL continuum peak, the yellow arrow corresponds in direction and length to the arrow in the left panel, in which the background image is a GLIMPSE 8  μm image with ATLASGAL contours (at 0.3 Jy, 0.4 Jy, 0.5 Jy, 0.7 Jy, 0.9 Jy, 1.3 Jy, 1.8 Jy, and 2.5 Jy) on top.