Comparison of the luminosities of sources with and without association with ATLASGAL sources. Left: shown is the distribution of the luminosities. The median value is 3.1 × 10⁻⁶ L_⊙ for the full sample and 4.7 × 10⁻⁶ L_⊙ and the subset of detections peaks that have ATLASGAL compact source catalogue (CSC) associations. Middle: CDF comparing the full sample of luminosities to the subset of sources that are associated with ATLASGAL where the two samples are not distinct. Right: CDF comparing the sample of luminosities without an ATLASGAL association to those with where they are seen to be statistically distinct.