The interaction of radio sources and cooling flows

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 also often a radio source at the centre of such a region. Data from Chandra now enable 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 3C 84, the coolest X-ray emitting gas occurs immediately around the inner radio lobes.