In situ particle acceleration and physical conditions in radio tail galaxies

A model for the objects known as radio tail galaxies is presented. Independent plasmons emerging from an active radio galaxy into an intracluster medium become turbulent due to Rayleigh-Taylor and Kelvin-Helmholtz instabilities. The turbulence produces both in situ betatron and second order Fermi acceleration. Predictions of the dependence of spectral index and flux on distance along the tail match observations well. Fitting provides values of physical parameters in the tail. The relevance of this method of particle acceleration for the problem of the origin of X-ray emission in clusters of galaxies is discussed.