We investigate the form and evolution of the X-ray luminosity-temperature (LX-kT) relation of a sample of 114 galaxy clusters observed with Chandra at 0.1 -kT) relation of a sample of 114 galaxy clusters observed with Chandra at 0.1 -kT) relation of a sample of 114 galaxy clusters observed with Chandra at 0.1 X-kT relation with a slope that agrees well with simple self-similar expectations. This is supported by an analysis of the gas density profiles of the systems, which shows self-similar behaviour of the gas profiles of the relaxed clusters outside the core regions. By comparing our data with clusters in the Representative XMM-Newton Cluster Structure Survey (REXCESS) sample, which extends to lower masses, we find evidence that the self-similar behaviour of even the most relaxed clusters breaks at around 3.5 keV.
