Astron. J., 124, 33-45 (2002/July-0)
Moderate-temperature clusters of galaxies from the RDCS and the high-redshift luminosity-temperature relation.
HOLDEN B.P., STANFORD S.A., SQUIRES G.K., ROSATI P., TOZZI P., EISENHARDT P. and SPINRAD H.
Abstract (from CDS):
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 profile and a bend in the distribution of X-ray emission. In contrast, RDCS 1350+6007 appears to be more like low-redshift clusters, with β=0.49±0.06 and rcore=165±5 kpc (Ωm=0.3, ΩΛ=0.7, H0=65 km.s–1.Mpc–1), though it also has an elliptical, slightly asymmetric surface brightness profile. We find a temperature of 3.7+1.5–0.9 keV and a bolometric luminosity of 8.2+1.7–1.6x1043 ergs.s–1 for RDCS 1317+2911, and a temperature of 4.9+1.3–0.9 keV and a bolometric luminosity of 4.1+0.5–0.4x1044 ergs.s–1 for RDCS 1350+6007. Our weak-lensing analysis of RDCS 1350+6007 confirms the general shape of the inner density profile but predicts twice the mass of the model based on the X-ray profile. 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 β 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 zmedian=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=L6(1+z)A(T/6 keV)α, we find α=2.9±0.4, L6=8.7±0.9x1044 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 σ 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.
Catalogs - Cosmology: Observations - Galaxies: Clusters: General - galaxies: clusters: individual (RDCS 1350+6007 (read: RDCS J1350+6007)) - galaxies: clusters: individual (RDCS 1317+2911 (read: RDCS J1317+2911)) - galaxies: clusters: individual (CXOU J0910.1+5419) - galaxies: clusters: individual (CXOU J1316.9+2914) - X-Rays
RDCS are RDCS J. Table 1 : MS 1054.4+0321 is a misprint for -0321 (1E 1054.5-0321), RX J1053.7+5753 is a misprint for RX J1053.7+5735, CDFS-CL1 = [GZW2002] XID 594.
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