Measuring Ωm with the ROSAT Deep Cluster Survey

摘要: We analyze the ROSAT Deep Cluster Survey (RDCS) to derive cosmological constraints from evolution of cluster X-ray luminosity distribution. The sample contains 103 galaxy clusters out z 0.85 and flux limit Flim = 3 × 10-14 ergs s-1 cm-2 (RDCS-3) in [0.5-2.0] keV energy band, with a high-redshift extension containing four at 0.90 ≤ 1.26 brighter than 1 (RDCS-1). assume models be specified by matter density parameter Ωm, rms fluctuation amplitude 8 h-1 Mpc scale σ8, shape for cold dark matter-like power spectrum Γ. Model predictions mass function are converted into two steps. First, we convert intracluster gas temperature assuming hydrostatic equilibrium. Then, is using most recent data on LX-TX relation nearby distant clusters. These include Chandra six 0.57 1.27. From RDCS-3 find Ωm 0.35 σ8 0.66 spatially flat universe constant, no significant constraint Γ (errors correspond σ confidence levels three fitting parameters). Even accounting both theoretical observational uncertainties mass-X-ray conversion, an Einstein-de Sitter model always excluded far more level. also show that number X-ray-bright RDCS-1 > 0.9 expected inferred < data.