III Jet-cloud interactions: bent jets

In section §5 various different mechanisms were described which can result in a considerable curvature of a radio jet in the plane of the sky as a result of kinetic effects of the host galaxy -mirror symmetric sources- or by the precession of the jets along a cone -inversion symmetric sources. Real hydrodynamic deflections can be caused either by the force produced by a wind of gas in a cluster of galaxies -radio trails sources- and also when the jet interacts with a stratified density region (such as a galaxy or a cloud). In this chapter, the physical mechanisms which produce the deflection of a jet which expands adiabatically are analysed. First of all, the case is discussed in which the velocities of the gas in the jet are non-relativistic and the jet interacts with an isothermal gas sphere and a cloud of gas which is in equilibrium with a dark matter halo. In both cases, the self gravity of the cloud is taken into account. The same calculations are repeated for the case in which the velocities of the gas inside the jet are relativistic. In this case, for simplicity, the self gravity of the corresponding stratified density region is not taken into consideration.