Professor Paul O'Brien

Professor of astrophysics and space science

School/Department: Physics & Astronomy, School of



Professor Paul O’Brien is Head of the Astrophysics Group in the School of Physics and Astronomy. He began his career at University College London, moving to the University of Oxford and then to Leicester where he is now a Professor of Astrophysics and Space Science. Professor O’Brien undertakes research directed at investigating compact objects in the universe. These include Gamma-Ray Bursts (GRB) at all wavelengths across a wide range in redshift and the electromagnetic counterparts to gravitational wave sources. He is involved in the development and exploitation of space and ground-based observatories including the Swift, SVOM and Einstein Probe satellites and the GOTO and CTA facilities, among others. He has a particular interest in the provision of high-energy facilities observing from X-ray to TeV energies.


Professor O’Brien’s research is directed at investigating compact objects in the universe. His main areas of study are: (a) Determining the source of energy in GRBs. GRBs are thought to be powered by the collapse of a massive star or (for the shorter duration ones) a binary merger involving two compact objects. In either case a black hole or a highly-magnetised neutron star (a magnetar) is formed which powers relativistic jets that carry energy into the surrounding material. The peak emission from GRBs can last from milli-seconds up to several hours followed by afterglow emission which decays gradually over many days to months. The enormous luminosity of GRBs enables them to be detected at all redshifts and hence they can be used as cosmic probes. (b) Identifying the electromagnetic counterparts to gravitational wave and neutrino sources. This is the field of research called "multi-messenger astrophysics". The sources are related to GRBs and other energetic phenomena. The search for counterparts is challenging due to the (usually) large error regions produced by GW and neutrino observatories. Rarely there may be a joint trigger (as happened for GW170817).


Professor O'Brien is an author on many hundreds of publications. His papers can be accessed on-line via the NASA Astrophysics Data System.

He also has a Google Scholar page.


Professor O’Brien supervises postgraduate research students and undergraduate students working on research projects. Primarily he supervises students in the areas of gamma-ray bursts and the search for electromagnetic counterparts to gravitational wave sources.


Professor O’Brien teaches on the undergraduate courses in the School of Physics and Astronomy. These include courses on core physics such as electricity and magnetism and mathematics, and also courses in astrophysics and space science.

Press and media

Astrophysical transients. Astrophysical observatories. Space science. Get in touch for media enquiries about my research activities or facilities.


Fellow of the Royal Astronomical Society, the American Astronomical Society and the International Astronomical Union.


PhD in astronomy
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