Distribution of the normalized distance between the dust continuum peaks and the mid-infrared sources within 30′′. Black line shows all sources from the WISE catalog, while the red line corresponds to the distribution of only the red sources (see text for details). As a comparison the same distribution for all MSX sources is shown in gray. Dashed lines show the Gaussian fits to these distributions, the maximum angular distance between mid-infrared sources, and ATLASGAL sources was determined as 3σ from this and is shown with a dashed line.