Simulations of Galaxy Clusters


Galaxy clusters inhabit the most massive dark matter haloes in the Universe. They also contain large amounts of hot gas which can be detected in both the X-ray and millimetre regions of the electromagnetic spectrum. Multi-wavelength observational studies of clusters allow us to probe many aspects of our cosmological model (such as the nature of dark matter and dark energy) as well as how galaxies evolve in such extreme environments. In order to fully interpret these data, simulations of the cluster population are essential, capturing the complex, non-linear processes at work in these systems such as energetic galactic winds and the accretion of substructures that stir up the hot gas.

We are currently undertaking an ambitious programme to simulate a cosmologically-representative sample of clusters with unprecedented detail. Our simulations use the same state-of-the-art code used to run the EAGLE simulation, thus incorporating many of the important physical processes required to produce realistic models of clusters. These simulations allow us to study how galaxy evolution in clusters is different to the field (by comparing with the EAGLE data) as well as test how processes such as star formation and feedback from active galactic nuclei affect the structure of a cluster's hot gas and dark matter halo.

The above image is an example of one of our simulations where the main cluster is at the bottom and is seen to be accreting two smaller clusters. In addition to the simulated galaxies, we also show the predicted X-ray emission from the hot gas in pink. A prominent feature towards the top-left of the image is the shock front in between the two largest clusters. Here, gas being compressed and heated as the two systems collide.