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 found either 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 indexes 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, . Published hydrodynamic simulations do not reproduce the peculiar shape of the observed temperature profile, probably suggesting that a fundamental ingredient is missing.
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Grandi et al. (2002) studied this question.