Prof Chris Collins and Dr Ivan Baldry
Clusters of galaxies are the largest gravitationally bound objects in the Universe. As such their evolution over cosmic time provides important constraints on the nature of dark matter and dark energy. Despite some progress in this field, we still do not understand key features of how structure on the scale of clusters grows from tiny fluctuations as represented by the "ripples" in the Cosmic Background Radiation, to massive clusters containing thousands of galaxies. Part of the reason for this lack of progress is that large representative surveys of clusters needed to tackle these questions have only recently become available. This project will use clusters from state-of-the-art cluster surveys such as Planck Surveyor Satellite, XCS from the XMM satellite, and the Gama Survey, to measure how quickly the clusters accumulate mass through galaxy in-fall into the cluster gravitational potential wells and how the distribution of mass within the clusters changes over time. The results will be compared with model predictions from cosmological simulations of the dark matter such as The Millennium Simulation, to provide direct and high impact results constraining the cosmological parameters and searching for new gravity physics. This project builds on the extensive experience and international profile of cluster work at the ARI and also offers the student opportunities to work with an international team with good prospects for collaborative travel and observing runs to 8m telescopes in Chile and Hawaii.