Scaling properties of X-ray clusters: The Chandra view

The study of X-ray clusters of galaxies, started 30 years ago, has revealed an increasing complexity in the thermodynamics of the X-ray emitting intracluster medium (ICM) as long as the sensitivity and the resolution of the X-ray satellites increased. At the same time, deep surveys detected several, unexpected, high-z clusters. Here we focus on the Chandra observations of the most distant X-ray selected clusters (0.3 < z < 1.3), in order to constrain their thermodynamic evolution. The X-ray scaling properties show hints of negative evolution in the luminosity-temperature and M-gas-temperature relations, and a positive evolution in the entropy-temperature relation. We find that the mean iron abundance at <z> = 0.8 is Z(Fe) = 0.25(-0.06)(+0.04) Z(circle dot), and at <z> similar to 1.2 is Z(Fe) = 0.35(-0.05)(+0.06) Z(circle dot), both measures consistent with no evolution with respect to the local value Z(Fe) similar or equal to 0.3 Z(circle dot). These results can provide interesting constraints on the thermodynamics of the ICM at large look back times, pointing towards a redshift z greater than or similar to 2 for the onset of non-gravitational processes.