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

Using Arcminute Microkelvin Imager (AMI) Sunyaev-Zel'dovich (SZ) observations towards 10 CLASH (Cluster Lensing and Supernova Survey with Hubble) 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 Navarro, Frenk and White/generalized Navarro, Frenk and White-based 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 effect observationally using the different dependences of SZ and X-ray signals to n(e) that cause different sensitivities to the shocking and/or fractionation produced by mergers. Plotting Y-X-M-gas relations (where Y-X = MgasT) derived from AMI SZ and from Chandra X-ray gives ratios of AMI and Chandra Y-X and M-gas 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 T-SZ and T-X estimates: all the other clusters (apart from one) have SZ and X-ray estimates of M-gas, T and Y-X that agree within r(500). We use SZ versus X-ray discrepancies in conjunction with Chandra maps and T-X profiles, making comparisons with simulated cluster merger maps in Poole et al. (2006) to identify disturbed members of our sample and estimate merger stages.