AGN fraction as a function of the stellar mass M_* of star-forming (upper panels) and quiescent galaxies (lower panels) at high redshift (right panels) and low redshift (left panels). The solid line represents the AGN fraction of the field galaxies (galaxies in the isolated regions between 6 R₅₀₀ and 7 R₅₀₀ of each cluster) and the dashed line the ratio of galaxies in the cluster centre (below 0.4 R₅₀₀). The dotted vertical line divides galaxies into low-mass and massive galaxies as defined in this work. The coloured bands represent the 68% confidence intervals obtained with binomial statistics (see Sect. 3).