The Universe today displays a hierarchy of structures: stars are gathered into galaxies, which are mostly grouped into clusters of varying sizes. These in turn are arranged along cosmic filaments, surrounding large voids. This rich structure is believed to have developed from the small fluctuations in density which we see imprinted on the cosmic microwave background under the driving force of gravity, acting primarily on the dark matter which dominates the mass budget of the Universe.

In this course we will study the way in which these structures develop, and the nature of the characteristic objects which emerge. Galaxies and clusters display many scaling relations which give clues to the processes which formed them. Finally, we will look at the way the observed properties and distribution of these structures can be used to draw conclusions about the fundamental properties of the Universe as a whole, and about its evolution.

By the end of the module students should be able to: Explain the process of linear growth of initially small density fluctuations in an expanding universe.  Understand the collapse of dark matter dominated halos, and the basic properties of the virialised systems which result. Understand the concept of mass function, and the power of this as a cosmological probe. Describe the methods used for cosmological simulations of structure development, the insights derived from them and the problems encountered. Describe the main characteristics of early and late type galaxies and the physical basis for these differences.  Understand the physical processes which affect galaxies within group and cluster environments, and the way these relate to observational properties.  Describe the main features of galaxy groups and clusters, and the way these are probed observationally. Explain the evidence for dark matter in galaxies and clusters, and understand how gravitational lensing can be used to probe mass directly.  Describe the scaling relations which are displayed by galaxies and clusters, and interpret these physically.  Understand how cosmic structure can be used to constrain the fundamental parameters of cosmology.  Develop skills of independent study, including extracting information from the research literature.  Achieve a more in-depth understanding of a selected area of cosmic structure development, assessed through a problem-solving activity.