The Standard Model of Powerful Radio Galaxies - and Why you should be losing sleep.
Hot spots are transient.
The break energy of a localized population of electrons depends on the history of their gains and losses, both radiative and adiabatic. This history depends on the global evolution of the source throughout its lifetime as well as the diffusion of particles into high and low magnetic field regions. The observed break frequency depends on the local magnetic field strength. It samples, in a complicated biased way, those electrons that are currently in high field regions but have experienced relatively small losses since their acceleration. Evidence - several IC sources not bright where radio bright 5.