2000ApJ...544..109M

We present the first measurements of the X-ray size-temperature (ST) relation in intermediate-redshift (z∼0.30) galaxy clusters. We interpret the local ST relation (z∼0.06) in terms of underlying scaling relations in the cluster dark matter properties, and then we use standard models for the redshift evolution of those dark matter properties to argue that the ST relation does not evolve with redshift. We then use ROSAT HRI observations of 11 clusters to examine the intermediate-redshift ST relation; for currently favored cosmological parameters, the intermediate-redshift ST relation is consistent with that of local clusters. Finally, we use the ST relation and our evolution model to measure angular diameter distances; with these 11 distances we evaluate constraints on Ω_M and Ω_Λ that are consistent with those derived from studies of Type Ia supernovae. The data rule out a model with Ω_M=1 and Ω_Λ=0 with 2.5 σ confidence. When limited to models where Ω_M+Ω_Λ=1, these data are inconsistent with Ω_M=1 with 3 σ confidence.