  The X-ray emission in many clusters of galaxies shows a central peak in
surface brightness coincident with a drop in temperature. These characterize a
cooling flow. There is often a radio source also at the centre of such regions.
Data from Chandra now enables us to map the interaction between the radio
source and the intracluster medium. Preliminary work shows no sign of heating
of the gas beyond the radio lobes, which are often devoid of cooler gas and so
appear as holes. In the case of the Perseus cluster around 3C84, the coolest
X-ray emitting gas occurs immediately around the inner radio lobes.
