Research in Theoretical Astrophysics

The Milky Way halo

Researchers at the ICC use high resolution simulations of Milky Way mass haloes and observational survey data to study how the Galaxy formed and evolved, and to test predictions of the cold dark matter model on small scales.

The Gigaparsec universe

We run large simulations of the formation of structure, populate these with galaxies and build mock catalogues to help with the analysis and exploitation of wide-field surveys. We also use these simulations and mock catalogues to find novel cosmological probes and test their potential in constraining models.

Galaxy Formation

Modelling the formation and evolution of galaxies is one of the toughest challenges in astrophysics as it requires many nonlinear processes to be followed, such as star formation and heating by AGN, which operate over vast ranges of length, time and mass scales. At the ICC, we pursue complementary routes to study how galaxies are made, which can be divided into gas dynamics simulations and semi-analytical modelling:

Semi-analytics

The ICC is one of the pioneers of the semi-analytical approach to modelling galaxy formation. The current semi-analytical code, GALFORM, makes an ab initio prediction of the star formation, merger and chemical enrichment histories of galaxies. GALFORM is implemented in high-resolution, large-volume N-body simulations of the hierarchical clustering of the dark matter, to predict the spatial distribution of galaxies. Such calculations are used to build mock catalogues for galaxy surveys such as Pan-STARRs and Euclid.

Simulations

The ultimate goal of our simulations is to generate a realistic universe inside the computer. The EAGLE project is a world leading simulation that incorporates all the processes of galaxy formation including the formation of stars, feedback and metal enrichment from supernovae as well as accretion onto, and feedback from, black holes. A key feature of the EAGLE project is that the simulation match most observed properties of the observed universe extremely well. The project will play a key role in allowing us to understand how galaxies form and evolve, and answer key questions about the most critical processes that shape the Universe around us.

Galaxy Surveys

ICC and CEA researchers are involved in several major galaxy surveys which we use to test theoretical predictions of galaxy formation and cosmology.

Dark Energy and Alternative Gravity

The ICC pioneers in the analysis of linear perturbation evolutions and carries out state-of-the-art simulations of large-scale structure formation in various theories of dark energy and alternative gravity. These are used in theoretical and numerical studies of the origin and nature of the accelerated cosmic expansion.

General Relativistic cosmological simulations and observations

As we enter the "precision cosmology" era, the discussion of general relativistic (GR) effects in cosmological observations has become important, not only because such effects are expected to be detected in future galaxy surveys, but also because their impact on model constraints and parameter estimation may not be negligible. ICC's research in this field involves the development of new, efficient and accurate simulation codes, and the running and analyses of simulations where GR effects are properly taken into account.

The Solar System

ICC researchers have developed image reconstruction software to produce the best available maps of the lunar and martian hydrogen/water ice. Other areas of study include Mercury's polar water ice deposits, the lunar argon exosphere, lunar volcanoes and hydrodynamical simulations of giant impacts of the sort that are common during planet formation.