Core positions as a function of frequency, assumed from B21. The data are fitted with two different power laws: one for the parabolic region (red curve) and one for the conical region (blue curve). In the former case, the best fit index is k_r = 0.57 ± 0.17, while in the latter, it is k_r = 0.93 ± 0.01. An index close to 1 is expected when assuming equipartition between the particles and magnetic field energy densities in the jet.