Fundamental Physics from Galaxies

The standard model of the universe is built on Einstein's theory of gravity (General Relativity) and the hypotheses of dark matter and dark energy. This combination is successful on both very large and very small scales, but there exists an intermediate scale -- that of galaxies -- where it is poorly tested. Leading competitors to the standard model produce distinct signatures in galaxies' structures and internal motions, which I aim to discover or rule out in this project. My key targets are i) a new ("fifth") force of nature, predicted generically by extensions to General Relativity, and ii) interactions between dark matter particles, known to explain several puzzling galactic phenomena yet poorly constrained. I will search for these by combining models of galaxy properties under a range of assumptions for gravitational and dark matter physics, statistical techniques for picking out small signals in large datasets, and supercomputer simulations of the evolution and behaviour of galaxies.