Moderate-temperature clusters of galaxies from the RDCS and the high-redshift luminosity-temperature relation

We present our discovery observations and analysis of RDCS 1317+ 2911, z = 0.805, and RDCS 1350+6007, z = 0.804, two clusters of galaxies identified through X-ray emission in the ROSAT Deep Cluster Survey ( RDCS). RDCS 1317+ 2911 has an unusual morphology in our Chandra observations, with an asymmetric surface brightness pro le and a bend in the distribution of X-ray emission. In contrast, RDCS 1350+6007 appears to be more like low-redshift clusters, with beta = 0.49 +/- 0.06 and r(core) = 165 +/- 5 kpc (Omega(m) = 0.3, Omega(Lambda) = 0.7, H-0 = 65 km s(-1) Mpc(-1)), though it also has an elliptical, slightly asymmetric surface brightness profile. Wefind a temperature of 3.7(-0.9)(+1.5) keV and a bolometric luminosity of 8.2(-1.6)(+1.5) x 10(43) ergs s(-1) for RDCS 1317+ 2911, and a temperature of 4.9(-0.9)(+1.5) keV and a bolometric luminosity of 4.1(-0.4)(+0.5)x 10(44) ergs s(-1) for RDCS 1350+6007. Our weak-lensing analysis of RDCS 1350+6007 confirms the general shape of the inner density pro le but predicts twice the mass of the model based on the X-ray pro le. There are two possibilities for this discrepancy: either there is a significant amount of mass near the redshift of the cluster that has not yet fallen into the potential well and shock-heated the gas, or, as we only see the X-ray emission from the core of the cluster, our model fails to describe the true shape of the underlying potential. We combine the X-ray luminosities and temperatures for RDCS clusters of galaxies with such measurements of other clusters at high redshift ( z > 0.7) and fit the luminosity-temperature relation. We find no statistically significant evolution in the slope or zero point of this relation at z(median) = 0.83. This result is in agreement with models of intracluster medium evolution with significant preheating or high initial entropy values. Quantifying the bolometric luminosity-temperature relation as L = L-6 (1 + z)(A) ( T/6 keV)(alpha), we find alpha = 2.9 +/- 0.4, L-6 = 8.7 +/- 0.9 x 10(44) ergs s(-1) and A = 0.3 +/- 0.2, or A = 0.4 +/- 0.2, depending on which low-redshift luminosity-temperature relation we compare with. With this result, we rule out at the 5 level the self-similar scaling model of intracluster medium evolution. We discuss how low-temperature, high-redshift clusters of galaxies will allow us to improve on this result, and we announce the discovery of two such objects, CXOU J0910.1+5419 and CXOU J1316.9+2914.