The X-ray properties of a sample of 11 high-redshift ( 0.6 < z < 1.0 ) clusters observed with Chandra and/or XMM-Newton are used to investigate the evolution of the cluster scaling relations .
The observed evolution in the normalisation of the \mathrm { L - T } , \mathrm { M - T } , \mathrm { M _ { g } - T } , and \mathrm { M - L } relations are consistent with simple self-similar predictions , in which the properties of clusters reflect the properties of the universe at their redshift of observation .
Under the assumption that the model of self-similar evolution is correct and that the local systems formed via a single spherical collapse , the high-redshift \mathrm { L - T } relation is consistent with the high-z clusters having virialised at a significantly higher redshift than the local systems .
The data are also consistent with the more realistic scenario of clusters forming via the continuous accretion of material .

The slope of the \mathrm { L - T } relation at high-redshift ( B = 3.32 \pm 0.37 ) is consistent with the local relation , and significantly steeper then the self-similar prediction of B = 2 .
This suggests that the same non-gravitational processes are responsible for steepening the local and high-z relations , possibly occurring universally at z \hbox to 0.0 pt { \raise 1.72 pt \hbox { $ > $ } } { \lower 2.58 pt \hbox { $ \sim$ } } 1 or in the early stages of the clusters ’ formation , prior to their observation .

The properties of the intra-cluster medium at high-redshift are found to be similar to those in the local universe .
The mean surface-brightness profile slope for the sample is \beta = 0.66 \pm 0.05 , the mean gas mass fractions within R _ { 2500 ( z ) } and R _ { 200 ( z ) } are 0.069 \pm 0.012 and 0.11 \pm 0.02 respectively , and the mean metallicity of the sample is 0.28 \pm 0.11 \mathrm { Z _ { \odot } } .