Unveiling the Structure of the Universe

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This is an ambitious proposal to advance our understanding of the structures observed in our Universe, ensuring the development of world-leading research in areas central to the Science Challenges in the STFC roadmap:The Non-Gaussian Universe and Inflationary Theory: According to the standard inflationary paradigm, the observed galaxies and other large-scale structure originated from quantum fluctuations in the early universe. We will confront these predictions from inflationary models with detailed statistical observations of the Planck satellite data of the cosmic microwave background. In complementary studies, moving beyond simple inflation models, we will exploit recent theoretical advances to make more precise predictions for the distribution of galaxies in our Universe.The Universe as a Fundamental Physics Laboratory: We will explore how astronomical observations can provide new information about fundamental physics. In particular, we will investigate whether there is astronomical evidence for the constancy of some fundamental constants of physics and whether there can be significant modifications to Einstein's theory of general relativity. These modifications may shed new light on why the expansion of the universe began accelerating a few billion years ago.Black Holes and Gravitational Physics: Gravitational waves are ripples in spacetime which form when black holes or neutron stars merge or in the supernova explosion of stars. They propagate across the universe at the speed of light and will enable us to view the universe in a qualitatively new way with advanced detectors expected to go online in a couple of years. We will study numerically and analytically the stability of black holes and the shape of their gravitational wave signals for comparison with future observations.Long-term Evolution of Extrasolar Planetary Systems: We study the long-term evolution of extrasolar planetary systems through their tidal interactions with the central star, which affect the spin and orbital motion and can cause planets to swell, migrate inwards and even be destroyed. We also study the long-term gravitational interactions of planets with the protoplanetary disc, which can excite elliptical motion and in some cases destroy planets.Magnetohydrodynamics of Accretion Discs: Gaseous discs around young stars and black holes are ubiquitous in the Universe and drive some of its most fascinating and important processes. Of these this project addresses: planet formation, powerful jets and outflows, disc warps, and the great outbursts of energy that characterise nascent stellar systems and dwarf novae. The thread linking these diverse phenomena is turbulence and magnetic fields in the gas, which we study through large-scale numerical simulations.Scale interactions in Solar and Stellar Magnetism: The Sun is like a giant machine, and its large scale magnetic features change fairly regularly and coherently, as shown by the well-known sunspot cycle. However motion in the Sun is very disordered. We shall investigate a theoretical model of the Sun's magnetic field that will show how these disordered flows can combine to produce the observed cycles. We shall also use novel image processing methods to learn more about the details of the small scale motions near the surface of the Sun.Spectroscopic Diagnostics for the Active Sun and Astrophysics: A deeper understanding of processes in the solar atmosphere will help us describe the energy release which heats the corona (to over a million degrees) and initiates solar flares and eruptions, leading to space weather events. Recent solar space observations (SoHO, Hinode, SDO) provide stunning images (see www.suntrek.org). However, the analysis of this data requires detailed knowledge of emission in the EUV. This information is provided by our group and made publicly available via a database called CHIANTI, which is now universally used in solar physics, and also astrophysics.