Physics and fate of jet related emission line regions
  At high redshift, extragalactic jets are associated with extended emission
line regions. We present global and local hydrodynamic simulations of the
interaction of jets with their environment relevant to this phenomenon. We
determine the fraction of kinetic energy and momentum of the jet that should
appear in the emission line gas. From momentum considerations, we argue that
the gas seen in outward motion in many examples must to a large part originate
from within the galaxy. The host galaxies should have been massive, gas rich
and heavily star forming galaxies. The expelled gas is not expected to return
to the galaxy quickly. The observed kinetic energy in the emission line gas
constrains the jet powers to be greater than 10^47 erg/s.
