The deflection of jets by clouds

The role of collisions between extragalactic jets and dense clouds in determining the appearance of high-redshift radio galaxies is discussed and investigated through numerical hydrodynamic simulations in three dimensions. The code has the facility to track jet material separately from ambient material. This allows us to use simplifying assumptions to calculate synthetic radio images. The results indicate that the most powerful radio sources are likely to be observed during or shortly after an interaction, and that such interactions can explain both the radio structures and the spatial association between optical and radio light found in powerful radio galaxies. In some cases such a scenario may provide an alternative explanation of jet properties to mechanisms based on variations in the source or fluid-dynamical instabilities.