Nicole Nesvadba (Obs.  Paris)

"Giant Outflows, Bubbles, and the Role of the Radio Jet:
AGN Feedback in High-Redshift Radio Galaxies seen with Integral-Field Spectroscopy"

AGN feedback has now become a major ingredient of galaxy evolution models,
taylored to solve some of the outstanding mysteries in the evolution of
massive galaxies. By postulating a dramatic phase of powerful AGN-driven
feedback, quenching star-formation at high redshift and removing the gas from
the surrounding dark matter halo, theorists try to accomodate the
seemingly "anti-hierarchical" growth of massive galaxies within the
hierarchical model, and to match the observed number of  massive galaxies
with what is predicted from the models.

However, direct observational evidence for AGN feedback is rare. Using the
imaging spectrograph SINFONI on the VLT, we recently identified giant
outflows of ionized gas in powerful radio galaxies at z~2-3 which seem
related to the mechanical energy input of the radio jet. Ionized gas masses
and kinetic energies suggest that significant fractions of the interstellar
medium are being unbound from the gravitational potential. Is this
the "smoking gun" of AGN feedback? Can a similar mechanism inhibit subsequent
gas cooling during a Hubble time? I will present our analysis of AGN feedback
in the early universe, review the observational evidence for AGN feedback
across cosmic time, and discuss why it may play a critical role for our
understanding of galaxy evolution.