Our broad research interests span some of the key physical processes which govern the evolution of the Universe. These processes operate on a wide range of scales, from the accretion of matter onto a black hole to the formation of elliptical galaxies via mergers of disk galaxies. The research interests of our staff members broadly relate to accretion processes and stellar dynamics, and there is close interaction between all staff members. Our weekly group meetings provide an opportunity for detailed discussion of all aspects of our on-going research. In addition to fostering interaction between group members, this also enables the students in the group get a clear picture of the research of the group as a whole.

Accretion onto a black hole is the most efficient way of extracting energy from conventional matter. Gravitational energy thus powers the most luminous objects in the Universe. At the same time, gravity's cumulative nature gives it a decisive role in determining the structure and evolution of matter at all scales. The theoretical understanding of these twin aspects - accretion, and the structure and evolution of the parent systems - are the key themes of our research, in various cosmic contexts.

Our research thus breaks down into two broad areas:

Accretion processes

On the smallest scale, close binary systems containing black holes offer a highly tractable route to studying accretion processes such as disc formation and stability. However, it is also important to understand the long-term evolution of these binaries themselves, and the standard and ultraluminous (ULX) X-ray populations of other galaxies. Similarly, astronomers want to understand how accretion onto supermassive black holes (SMBH) powers active galactic nuclei (AGN). However, they also wish to know how these objects fit into the general picture of galaxy structure and formation, as clearly signalled by the observed relation between central SMBH mass and velocity spread of the stars in the host galaxy. Gamma-ray bursts (GRBs) offer another example where the study of accretion processes is closely linked to understanding the host galaxy, and stellar and binary evolution within it. The physical processes we study are also relevant to the understanding of star formation and proto-planetary disks, and group members are active in these fields also.

Group members with interests in this area:

• Andrew King
• Richard Alexander
  
• Sergei Nayakshin
• Graham Wynn

Stellar dynamics

Stellar dynamics, or the study of the motions of stars, is a powerful tool for understanding the Universe. It can be used to probe the dark matter content of galaxies and to understand the evolutionary history of galaxies, including our own Milky Way. We use a range of techniques, including N-body simulations and analytical modelling, to provide new insights into fundamental dynamical processes and to interpret observed data. Our future research plans include deriving tight constraints on the nature of the non-luminous dark matter which makes up about 25% of the mass budget of the Universe, studying in detail the disruption of satellite galaxies by the Milky Way and developing new dynamical models of the Milky Way which can be used to interpret the data obtained from the next generation of observational surveys.

Group members with interests in this area:

• Walter Dehnen
• Mark Wilkinson
  
• Justin Read
  

A full list of our group's publications is available.