The Dark Matter Haloes of Chandra X-ray Galaxy Clusters and Baryons Effect. (arXiv:1208.2424v1 [astro-ph.CO])

The Dark Matter Haloes of Chandra X-ray Galaxy Clusters and Baryons Effect. (arXiv:1208.2424v1 [astro-ph.CO]):
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 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.

The inner slope $\alpha$ of the total mass density profile (\rho(r)\propto
r^{-\alpha}) is derived from the slope of the integrated mass profile, using a
generalized NFW model. The values of the inner slope \alpha, is \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.