Using C-EAGLE to determine the velocity bias of galaxies in clusters
Thomas J. Armitage
University of Manchester
Scott T. Kay, David J. Barnes
The velocity dispersion of a cluster has been shown to be tightly related to its mass, making it useful as a proxy. However, the velocity bias between the baryons forming galaxies and the underlying dark matter needs to be well understood. The C-EAGLE simulations, the core sample of which are 30 cosmologically representative massive clusters generated using the same code as EAGLE with a mass resolution Mgas=1.8*10^6 Msun, are the first time galaxies have been well-resolved in a cluster environment. These simulations allow a comparison between the velocity dispersion of the dark matter as a whole, the dark matter halos, and the galaxies inside those halos. This work focuses on characterising any biases between the stars and dark matter, and investigating whether they are a function of cluster mass, galaxy mass, radial distance from the cluster, or redshift. Mock observations are also simulated to account for projection effects and contamination from background and foreground galaxies.