X-ray properties in massive galaxy clusters: XMM-Newton observations of the REFLEX-DXL sample ⋆

We selected an unbiased, flux-limited and almost volume-com plete sample of 13 distant, X-ray luminous (DXL, z ∼ 0.3) clusters and one supplementary cluster at z = 0.2578 from the REFLEX Survey (the REFLEX-DXL sample). We performed a detailed study to explore their X-ray properties using XMM-Newton observations. Based on the precise radial distributions of the gas density and temperature, we obtained robust cluster masses and gas mass fractions. The average gas mass fraction of the REFLEX-DXL sample at r500, 0.116± 0.007, agrees with the previous cluster studies and the WMAP baryon fraction measurement. The scaled profiles of the surf ace brightness, temperature, entropy, gas mass and total mass are characterized by a self-similar behaviour at radii above 0. 2-0.3 r500. The REFLEX-DXL sample confirms the previous studies of the normalization of the scaling relations ( L-T , L-M, M-T and Mgas-T ) when the redshift evolution of the scaling relations is accounted for. We investigated the scatter of the scaling relations of the REFLEX-DXL sample. This gives the correlative scatter of (0.20,0.10) for variable of ( M,T ) of the M500-T relation, for example.