Left panel: comparison between the number of cosmological neighbors within a diameter of 2000 kpc () and the number of galaxies (N_gal) associated with the groups or clusters hosting the radio sources from T12. Black dots show FR 0s, and blue and red dots represent FRICAT and sFRICAT objects, respectively. The inset in the top right corner is a zoom into the regions of low N_gal values. Right panel: field around SDSS J111113.18+284147.0 as an example of objects with a large discrepancy between N_gal and . Cosmological neighbors are shown as red circles, and the green points mark the location of the closest (in projection) groups or clusters of galaxies with a redshift difference Δz <  0.005, listed in the T12 galaxy cluster and group catalog.