Histogram of the separations (angular distances) between the peak of the HC₃N* emission and peak of the H40α emission for sources associated with UC HII regions (left panel) and the separations between the peak of the HC₃N* emission and peak of the continuum emission for sources without UC HII regions (right panel). The blue bars represent sources with angular distances greater than zero, and the purple bars represent sources with angular distances equal to zero.