AGN Feedback in groups and clusters of galaxies
  The lack of very cool gas at the cores of groups and clusters of galaxies,
even where the cooling time is significantly shorter than the Hubble time, has
been interpreted as evidence of sources that re-heat the intergalactic medium.
Most studies of rich clusters adopt AGN feedback to be this source of heating.
  From ongoing GMRT projects involving clusters and groups, we demonstrate how
low-frequency GMRT radio observations, together with Chandra/XMM-Newton X-ray
data, present a unique insight into the nature of feedback, and of the energy
transfer between the AGN and the IGM.
