  In recent years it has become increasingly clear that Active Galactic Nuclei,
and radio-galaxies in particular, have an impact on large scale structure and
galaxy formation. In principle, radio-galaxies are energetic enough to halt the
cooling of the virialized intracluster medium (ICM) in the inner regions of
galaxy clusters, solving the cooling flow problem and explaining the high-mass
truncation of the galaxy luminosity function. We explore this process through a
series of high resolution, three dimensional hydrodynamic simulations of jetted
active galaxies that act in response to cooling-mediated accretion of an ICM
atmosphere. We find that our models are incapable of producing a long term
balance of heating and cooling; catastrophic cooling can be delayed by the jet
action but inevitably takes hold. At the heart of the failure of these models
is the formation of a low density channel through which the jet can freely
flow, carrying its energy out of the cooling core. It is possible that this
failure is due to an over-simplified treatment of the fast jet (which may
underestimate the ``dentist drill'' effect). However, it seems likely that
additional complexity (large-angle jet precession or ICM turbulence) or
additional physics (magnetohydrodynamic effects and plasma transport processes)
is required to produce a spatial distribution of jet heating that can prevent
catastrophic cooling. This work also underscores the importance of including
jet dynamics in any feedback model as opposed to the isotropically inflated
bubble approach taken in some previous works.

Astrophysics