LoCuSS: comparison of observed X-ray and lensing galaxy clusterscaling relations with simulations

The Local Cluster Substructure Survey (LoCuSS, Smith et al.) is a systematic multi-wavelength survey of more than 100 X-ray luminous galaxy clusters in the redshift range 0.14-0.3 selected from the ROSAT All Sky Survey. We used data on 37 LoCuSS clusters from the XMM-Newton archive to investigate the global scaling relations of galaxy clusters. The scaling relations based solely on the X-ray data (, , , , , , , , , and ) obey empirical self-similarity and reveal no additional evolution beyond the large-scale structure growth. They also reveal up to 17 per cent segregation between all 37 clusters and non-cool core clusters. Weak lensing mass measurements are also available in the literature for 19 of the clusters with XMM-Newton data. The average of the weak lensing mass to X-ray based mass ratio is , setting the limit of the non-thermal pressure support to per cent. The mean of the weak lensing mass to X-ray based mass ratio of these clusters is ~1, indicating good agreement between X-ray and weak lensing masses for most clusters, although with 31-51 per cent scatter. The scatter in the mass-observable relations (, , and ) is smaller using X-ray based masses than using weak lensing masses by a factor of 2. With the scaled radius defined by the YX profile – , , and , we obtain lower scatter in the weak lensing mass based mass-observable relations, which means the origin of the scatter is Mwl and instead of YX. The normalization of the relation using X-ray mass estimates is lower than the one from simulations by up to 18–24 per cent at significance. This agrees with the relation based on weak lensing masses, the normalization of the latter being ~20 per cent lower than the one from simulations at ~ significance. This difference between observations and simulations is also indicated in the and relations. Despite the large scatter in the comparison of X-ray to lensing, the agreement between these two completely independent observational methods is an important step towards controlling astrophysical and measurement systematics in cosmological scaling relations.