Overdensities of detected sources with S/N > 4 in different apertures in arcminutes (colored vertical lines) compared to the density distribution functions of overdensities from 500 realizations of 20 mock blank fields with similar noise properties as the 20 science maps, each divided by their mean value (gray distributions). The overdensity in each aperture is detected at a high significance, with the strength of the overdensity decreasing from the central to the outer aperture (see Table 5). The errors on overdensities take into account the Poisson uncertainties on the counts. The significance of the overdensities also taking the Gaussian “background” into account is given in Table 5.