Simulations of the interaction of cold gas with radio jets

A new scenario for the interaction of a jet with a background medium with cold clouds is investigated by means of hydrodynamic turbulence simulations with cooling. The idea is that the cold clouds are overtaken by a radio cocoon and stirred up by turbulence in this cocoon. The 2D multiphase turbulence simulations contain all the three gas phases and have a number of interesting properties. The produced power spectrum is proportional to the inverse square of the wavevector. The Mach number - density relation may explain the observed velocities in emission line gas associated with radio galaxies. The model also explains the increased optical visibility within the radio structures, the correlation between emission line and radio luminosity, and the evolution of the alignment effect with source size. I also propose this to be a useful model for the recently discovered neutral outflows in nearby radio sources.