Left panel: projected radial density profiles (left ordinate) of the galaxy surface number (black) and the ICM (red) in nearby (z ≤ 0.08) clusters, normalized at a radius of 0.05 R₅₀₀. Both data are taken from the sample of Gu et al. (2016). The ICM to galaxy density ratio is plotted in blue (right ordinate). Right panel: observed GNIMR profiles averaged over clusters in different redshift bins. This plot shows a combination of two samples, 34 clusters (z = 0.1−0.9) from Gu et al. (2013a, open symbols), and 340 clusters (z = 0−0.5) from Gu et al. (2016, filled symbols). Error bars are at the 1σ level. The r-band luminosity functions of the identified member galaxies from the 340 cluster sample in different redshift bins are shown in the inset.