Dynamical Age vs Spectral Age of the Lobes of Selected Giant Radio Sources (GRSs)

Dynamical ages of the opposite lobes determined {\sl independently} of each other suggest that their ratios are between $\sim$1.1 to $\sim$1.4. Demanding similar values of the jet power and the radio core density for the same GRS, we look for a {\sl self-consistent} solution for the opposite lobes, which results in different density profiles along them found by the fit. A comparison of the dynamical and spectral ages shows that their ratio is between $\sim$1 and $\sim$5, i.e. is similar to that found for smaller radio galaxies. Two causes of this effect are pointed out.