Pressure in Shells

• In cooling flow clusters, surface brightness deprojected to determine X-ray emissivity and density.

• Common feature of these sources is that the pressure of the bright shells is ~ equal to that just outside of them => no evidence for strong shocks.

• Comparison with the gas pressure in the X-ray shells with the pressures derived in the holes from radio observations, assuming equipartition, shows that the pressures in the shells are about an order of mag. higher than the radio pressures.