Results from the spectroscopic redshift samples. Ratio of annular surface densities of galaxies around quasars (ρ_quasars) and the annular surface densities of galaxies around central non-AGN field galaxies (ρ_field) as function of projected distance. The field galaxies were chosen to be inside the same magnitude range as the quasars in order to compare objects of same mass range, having  −24 < M_r <  −19. The plot includes AGN among the companion galaxies. In the left column: blue galaxies with U_e − R_e < 2.2, in right column: all galaxies. Three different redshift difference cuts  | Δz |  are pictured for the pairs, top:  | Δz |  = 0.001, middle:  | Δz |  = 0.006, bottom:  | Δz |  = 0.012. The ratio is normalized for the difference in sample size.