Models of AGN feedback
  The physical processes responsible of sweeping up the surrounding gas in the
host galaxy of an AGN, and able in some circumstances to expel it from the
galaxy, are not yet well known. The various mechanisms are briefly reviewed:
quasar or radio modes, either momentum-conserving outflows, energy-conserving
outflows, or intermediate. They are confronted to observations, to know whether
they can explain the M-sigma relation, quench the star formation or whether
they can also provide some positive feedback and how the black hole accretion
history is related to that of star formation.
