X-Ray Scaling Relations for a Representative Sample of Planck-selected Clusters Observed with XMM-Newton

Abstract

We report the scaling relations derived by fitting the X-ray parameters determined from analyzing the XMM-Newton observations of 120 galaxy clusters in the Planck Early Sunyaev–Zel’dovich (SZ) sample spanning the redshift range of 0.059 <  z < 0.546. We find that the slopes of all the investigated scaling relations significantly deviate from the self-similar predictions, if self-similar redshift evolution is assumed. When the redshift evolution is left free to vary, the derived slopes are more in agreement with the self-similar predictions. Relaxed clusters have on average ∼30% higher X-ray luminosity than disturbed clusters at a given mass, a difference that, depending on the relative fraction of relaxed and disturbed clusters in the samples (e.g., SZ vs. X-ray selected), has a strong impact on the normalization obtained in different studies. Using the core-excised cluster luminosities reduces the scatter and brings into better agreement the L– M _tot and L– T relations determined for different samples. M _tot– T, M _tot– Y _X, and M _tot– M _gas relations show little dependence on the dynamical state of the clusters, but the normalizations of these relations may depend on the mass range investigated. Although most of the clusters investigated in this work reside at relatively low redshift, the fits prefer values of γ, the parameter accounting for the redshift evolution, different from the self-similar predictions. This suggests an evolution (<2 σ level, with the exception of the M _tot– T relation) of the scaling relations. For the first time, we find significant evolution (>3 σ) of the M _tot– T relation, pointing to an increase of the kinetic-to-thermal energy ratio with redshift. This is consistent with a scenario in which higher-redshift clusters are on average more disturbed than their lower-redshift counterparts.