Galaxy Clusters Near and Far
Measuring the masses of massive galaxy clusters
Monique A. Henson
David J. Barnes (University of Manchester), Scott T. Kay (University of Manchester), Ian G. McCarthy (Liverpool John Moores University)
University of Manchester
Accurate mass measurements of galaxy clusters are a vital tool in modern cosmology, providing a unique insight into the nonlinear regime. There has been a wealth of work characterising the bias in X-ray and weak lensing mass measurements using numerical simulations, however these have been restricted to clusters with masses less than 10^15 solar masses or dark matter only simulations. The MACSIS project is a set of hydrodynamical simulations of massive galaxy clusters which extends the BAHAMAS sample of galaxy groups and clusters to higher masses. These simulations use the sub-grid physics models developed in the BAHAMAS project, which includes feedback from supernovae and active galactic nuclei. Taken with the BAHAMAS sample, the simulations form a cluster population which covers almost two orders of magnitude in mass, with more than 250 clusters with masses greater than 10ˆ15 solar masses at z=0. Since these simulations consist of both dark matter only and hydrodynamic simulations, they are ideal for investigating the impact of baryons on cluster weak lensing. Together with the calculated X-ray observables of MACSIS clusters, these are used to infer the hydrostatic mass bias for massive galaxy clusters and its dependence on cluster properties. In this talk I will begin by discussing how baryons affect the weak lensing shear profiles of massive galaxy clusters and the implications of this for cluster mass measurements. I will conclude by presenting the hydrostatic mass bias as found in the MACSIS simulations in the context of recent observations.
16:30 - 18:00
EX - LT3 (320)