Group Research

The group's research interests are broadly described under the two themes of accretion processes and dynamics, but these broad themes cover a very wide range of physical systems. These processes are critical to understanding the evolution of the Universe on a wide range of scales, from exoplanets, to super-massive black holes, to mergers of galaxies. This broad approach allows for close interaction between all group members, and 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 of gas on to compact objects plays a critical role in the formation of stars, planets, and black holes, and accretion on to black holes is the most efficient way of extracting energy from conventional matter. 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 three broad areas:

Accretion processes

On the smallest scales, 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.

Group members with interests in this area:

Planet formation

The last few years have seen an explosion in our knowledge of extra-solar planets, and we now understand that most, if not all stars host planetary systems. However, most exoplanet systems bear little resemblance to the solar system, and the origin of the enormous diversity in observed planetary systems remains unclear. Our research in this field uses large numerical simulations to understand the myriad of processes that shape planetary systems: how planets form in discs around young stars; how those protoplanetary discs evolve; how planets migrate; and how planetary systems are built. We also work closely with observers of both protoplanetary discs and exoplanets, in Leicester and elsewhere, in order to build up a comprehensive picture of how planetary systems form and evolve.

Group members with interests in this area:

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:

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