Radio flux densities of models plotted as a function of the black hole event horizon angular velocity (left panel), and as a function of the angular velocity of the matter in the disk at the ISCO (right panel). We show the radio flux densities at two frequencies; ν₁ = 86 (filled circles) ν₂ = 43 (open circles) GHz at which the SEDs are close to flat and optically thick. The flux densities are given in arbitrary units since they depend on the distance to the source that is not specified here. The emission is computed for a fixed mass of the black hole and a fixed accretion rate. The lines show the best fits to the synthetic data points. The best-fit parameters, along with the form of the fitting function, are given in Table 3.