The evolution of the galaxy cluster luminosity-temperature relation

We analyzed the luminosity-temperature (L-T) relation for two samples of galaxy clusters that have been observed by the ASCA satellite. We used 32 high-redshift clusters (0.3<z<0.6), 53 low-redshift clusters (z<0.3), and also the combination of the low- and high-redshift data sets. This is one of two surveys to use only ASCA data and has the largest number of high-redshift clusters. We assumed a power-law relation between the bolometric luminosity of the galaxy cluster and its integrated temperature ( uncorrected for cooling flows) and redshift [L-bol,L-44 = CT alpha(1+z)(A)]. We found that for an Omega(M)=1.0, Omega(Lambda)=0.0 universe, A=1.134(-1.073)(+1.057)+/-1.66, alpha=2.815(-0.316)(+0.322)+/-0.42, and log C=-1.167(-0.221)(+0.216)+/-0.25, and for an OmegaM=0.3, Omega(Lambda)=0.7 universe, A=2.052(-1.058)(+1.0763)+/-1.63, alpha=2.822(-0.323)(+0.320)+/-0.43, and log C=-1.126(-0.219)(+0.223)+/-0.26 (all errors at 68% confidence for one and two interesting parameters). We found the dispersion at constant kT in this relation to be Delta log L=0.282 for Omega(M)=1.0, Omega(Lambda)=0.0, and Delta log L=0.283 for Omega(M)=0.3, Omega(Lambda)=0.7. The results for the combined data set and those found using the low- and high-redshift clusters are consistent and independent of cosmology, with previous estimates of Lsimilar toT(3) found by other authors. The observed weak or zero evolution agrees with the predictions of models that produce Lsimilar toT(3) incorporating an initial source of nongravitational energy before cluster collapse.