LoCuSS: comparison of observed X-ray and lensing galaxy cluster scaling 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 ($S{-}T$, $S{-}Y_{\rm X}$, $P{-}Y_{\rm X}$, $M{-}T$, $M{-}Y_{\rm X}$, $M{-}M_{\rm gas}$, $M_{\rm gas}{-}T$, $L{-}T$, $L{-}Y_{\rm X}$, and $L{-}M$) 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 $1.09\pm 0.08$, setting the limit of the non-thermal pressure support to $9 \pm 8$ 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 ($M{-}Y_{\rm X}$, $M{-}M_{\rm gas}$, and $M{-}T$) 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 – $r_{500}^{ Y_{\rm X},X}$, $r_{500}^{Y_{\rm X},{\rm wl}}$, and $r_{500}^{Y_{\rm X},{\rm si}}$, we obtain lower scatter in the weak lensing mass based mass-observable relations, which means the origin of the scatter is Mwl and $M^{\rm X}$ instead of YX. The normalization of the $M{-}Y_{\rm X}$ relation using X-ray mass estimates is lower than the one from simulations by up to 18–24 per cent at $3\sigma$ significance. This agrees with the $M{-}Y_{\rm X}$ relation based on weak lensing masses, the normalization of the latter being ~20 per cent lower than the one from simulations at ~$2\sigma$ significance. This difference between observations and simulations is also indicated in the $M{-}M_{\rm gas}$ and $M{-}T$ 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