Luminosity function of sources that match the compactness criteria laid out in Sect. 4.2 in various elliptical annuli surrounding the BCG (red, yellow, purple, and green lines). These sources include contamination from background sources as well as GC-candidates. The luminosity function of background sources (grey histagram) has been calculated from sources in the area beyond a > 600 kpc which also match the compactness criteria laid out in Sect. 4.2. The greyed-out area marks the portions of the luminosity functions where the source selection is less than 95% complete.