  We report results from the analysis of 21 nearby galaxy clusters, 11 with
cooling flow (CF) and 10 without cooling flow, observed with BeppoSAX. The
temperature profiles of both CF and non-CF systems are characterized by an
isothermal core extending out to 0.2 r_180; beyond this radius both CF and
non-CF cluster profiles rapidly decline. Our results differ from those derived
by other authors who either found continuously declining profiles or
substantially flat profiles. Neither the CF nor the non-CF profiles can be
modeled by a polytropic temperature profile, the reason being that the radius
at which the profiles break is much larger than the core radius characterizing
the gas density profiles. For r > 0.2 r_180, where the gas can be treated as a
polytrope, the polytropic indices derived for CF and non-CF systems are
respectively 1.20 +/- 0.06 and 1.46 +/- 0.06. The former index is closer to the
isothermal value, 1, and the latter to the adiabatic value, 5/3. Published
hydrodynamic simulations do not reproduce the peculiar shape of the observed
temperature profile, probably suggesting that a fundamental ingredient is
missing.
