The Dark Matter Haloes of Chandra X-ray Galaxy Clusters and Baryons
  Effect
  We present results based on Chandra observations of a large sample of 129 hot
galaxy clusters. We measure the concentration parameter c_200, the dark mass
M_200 and the baryonic mass content in all the objects of our sample, providing
the largest dataset of mass parameters for galaxy clusters in the redshift
range z = 0.01 - 1.4. We confirm a that a tight correlation between c_200 and
M_200, c \propto M^a_vir /(1+z)^b with a = -0.56 +/- 0.15 and b =0.80 +/- 0.25
(68 per cent confidence limits), is present, in good agreement with the
predictions from numerical simulations and previous observations. Fitting the
mass profile with a generalized NFW model, we got the inner slope alpha, with
alpha = 0.94 +/- 0.13. Finally, we show that the inner slope of the density
profile, alpha correlates with the baryonic mass content, M_b : namely alpha is
decreasing with increasing baryonic mass content.
