Example of how luminosity thresholds L_t, SF and L_t, AGN (blue and red dashed lines, respectively) were defined. Top: radio luminosity function (Φ_TOT; orange line), constrained by the data at 2.23 <  z <  2.69, is separated into a lower-luminosity “bump” (Φ_SF; dot-dashed blue line) and the higher-luminosity double power-law (Φ_AGN; dot-dashed red line). Bottom: ratios of the SF (Φ_SF) and AGN (Φ_AGN) contributions to the total RLF (Φ_TOT) as a function of L_{1.4 GHz} are shown by blue and red lines, respectively. L_t, SF and L_t, AGN are values of L_1.4 GHz below and above which more than 80% of sources used to constrain the RLF are dominated by star formation and AGN-related radio emission, respectively. In both panels, the gray area shows the region of the plot in which the curves are just an extrapolation of the analytic forms of RLFs below the detection limits of radio data used to constrain them.