AMI observations of 10 CLASH galaxy clusters: SZ and X-ray data used together to determine cluster dynamical states

Using Arcminute Microkelvin Imager (AMI) SZ observations towards ten CLASH clusters we investigate the influence of cluster mergers on observational galaxy cluster studies. Although selected to be largely relaxed, there is disagreement in the literature on the dynamical states of CLASH sample members. We analyse our AMI data in a fully Bayesian way to produce estimated cluster parameters and consider the intrinsic correlations in our NFW/GNFWbased model. Varying pressure profile shape parameters, illustrating an influence of mergers on scaling relations, induces small deviations from the canonical self-similar predictions – in agreement with simulations of Poole et al. (2007) who found that merger activity causes only small scatter perpendicular to the relations. We demonstrate this eect observationally using the dierent dependencies of SZ and X-ray signals to ne that cause dierent sensitivities to the shocking and/or fractionation produced by mergers. Plotting YX–Mgas relations (where YX = MgasT) derived from AMI SZ and from Chandra X-ray gives ratios of AMI and Chandra YX and Mgas estimates that indicate movement of clusters along the scaling relation, as predicted by Poole et al. (2007). Clusters that have moved most along the relation have the most discrepant TSZ and TX estimates: all the other clusters (apart from one) have SZ and X-ray estimates of Mgas, T and YX that agree within r500.We use SZ vs X-ray discrepancies in conjunction with Chandra maps and TX profiles, making comparisons with simulated cluster merger maps in Poole et al. (2006), to identify disturbed members of our sample and estimate merger stages.