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Galaxy Clusters: A Standard Cannon for Cosmology

Title: Galaxy Clusters: A Standard Cannon for Cosmology

Speaker: Professor Christopher J. Miller (University of Michigan, Ann Arbor USA)

Time: 14:00pm, April 19, 2023

Location: 3-302, PMO Xianlin Campus

Abstract: Einstein’s theory of general relativity (GR) entwines the dynamics of matter-energy and the universe's spacetime expansion. Recent authors have revised our understanding of the mathematics of dynamical tracers within the context of GR for an accelerating space-time metric. As a consequence, we have a new understanding of how the escape speed relates to the local potential via the Poisson equation. General relativity requires that the escape velocity for a massive extended object like a galaxy cluster be reduced compared to its Newtonian counterpart. In fact, the combined weak lensing and escape profiles of clusters provide a new dynamical probe of the expansion history of the universe. I will give a description of the theory, results from tests using increasingly realistic simulations, and examples from the first applications of this technique to real data. I will then discuss the future prospects of this new cosmological tool in the context of surveys like LSST and DESI.