Extragalactic Astrophysics

Black Holes

What are the underlying physical mechansism driving the ejection of matter at nearly the speed of light from the hearts of black holes? Researchers within the extragalactic astrophysics group are leading the charge to understand these mysterious objects.

Galaxy Dynamics

The galaxy dynamics group at the Jeremiah Horrocks Institute studies the dynamics of galaxies, including the Milky Way, to understand their formation and evolution. Our main approach is using supercomputer simulations to model the cooling of gas inside dark matter halos leading to star formation, and supernovae explosions. One of the key issues we are currently working on is the formation of nuclear star clusters that are often present at the centres of galaxies and their relation to supermassive black holes millions of times more massive than the Sun.

Stellar Poplations

Populations of stars in galaxies can tell us a lot about the formation and evolution of galaxies and their various structural components. Spiral galaxies are complex systems, with multiple components including disks, bulges, bars and spiral arms, whereas spheroidal galaxies such as dwarf spheroidals and dwarf and giant ellipticals are dominated by a single structural component. Early-type galaxies consist of elliptical (E) and lenticular (S0) galaxies that generally have lower levels of on-going star formation than spiral galaxies. However, exactly when their stars were made is hard to uncover. In most external galaxies we cannot resolve individual stars, but instead we observe the light from populations of stars


Dr Roger Clowes leads an international team investigating quasars. More specifically the grouping of quasars together to form a large scale structure but also the enviroment surrounding these quasars and the quasar emission

Quasars are the nuclei of galaxies from the early years of the universe. Quasars undergo brief periods of extremely high brightness that make them visible across huge distances. These periods are ‘brief’ in astrophysics terms but actually last 10-100 million years.

One such structure discovered by Dr Clowes is the Huge-LQG. With a characteristic size (volume1/3) ∼ 500 Mpc (present epoch). Whole clusters of galaxies can be 2-3 Mpc across, but LQGs can be 200 Mpc or more across.

Interstellar Medium

The Interstellar Medium Group led by Prof. Cristina Popescu investigates the formation and evolution of galaxies by studying the detailed physical processes that take place in these complex systems related to the interaction of radiation with dust, gas and cosmic rays