부산대학교 도서관

We investigate the properties of cool cores in an optimally selected sample of 37 massive and X-ray-bright galaxy clusters, with regular morphologies, observed with Chandra. We measured the density, temperature, and abundance radial profiles of their intracluster medium (ICM). From these independent quantities, we computed the cooling (tcool) free-fall (tff), and turbulence (teddy) timescales as a function of radius. By requiring the profile-crossing condition, tcool=teddy=1, we measured the cool-core condensation radius Rccc, within which the balancing feeding and feedback processes generate the turbulent condensation rain and related chaotic cold accretion (CCA). We also constrained the complementary (quenched) cooling flow radius Rqcf, obtained via the condition tcool=25Xtff, that encompasses the region of thermally unstable cooling. We find that in our cluster sample and in the limited redshift range considered (1.3E14Comment: A&A, in press, 25 pages, 8 figures