Professor Paul O'Brien

photoProfessor of Astrophysics and Space Science

BSc (Hons, University of London), PhD (University of London)

Tel: 0116 252 5203


Office: Room G19, Physics & Astronomy Department


Professor O'Brien began his career at University College London, obtaining a BSc in Astronomy. He then obtained a PhD in Astronomy at UCL on the Ultraviolet Emission from Quasars. Professor O'Brien worked as a postdoctoral research scientist at UCL, including a period as a UK scientist on the NASA/ESA/UK International Ultraviolet Explorer satellite project, before being appointed to a fixed-term lectureship at the University of Oxford in 1993. He moved to the University of Leicester as a lecturer in 1996 and is now a Professor of astrophysics and space science in the Physics and Astronomy Department.

Research interests

My observational research is directed at investigating compact objects in the universe. These include black holes in Active Galactic Nuclei (AGN) and Gamma-Ray Bursts (GRB) at all wavelengths across a wide range in redshift. AGN and GRBs are some of the most luminous objects known. My main areas of study are:

  • 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.
  • Understanding the origin and evolution of AGN and how they interact with their host galaxies. Powered by the accretion of matter onto supermassive black holes in the centre of galaxies, AGN are the most powerful steady sources of energy in the universe and may be a stage in the life cycle of every galaxy. Understanding AGN helps us to probe the behaviour of matter under extreme conditions and better understand the evolution of galaxies.

Much of my research is collaborative, involving scientists in the UK, Europe and the USA. I'm a member of the Space and High Energy Astrophysics Division (XI) of the International Astronomical Union, the body which oversees astronomy worldwide. I'm also a Fellow of the Royal Astronomical Society and its US equivalent, the American Astronomical Society.

To obtain spectroscopic and imaging data, I use a wide variety of ground-based and orbiting observatories, many including instrumentation built at Leicester, such as XMM-Newton, Chandra and Swift. I am currently involved in the development of new missions, including SVOM, JWST and Athena, and am part of teams studying other future high-energy facilities to search for high-redshift GRBs and other transient X-ray sources. I'm also part of the consortium developing the Cherenkov Telescope Array for very high energy astronomy.


In 2015/16 I taught on these courses:

  • First year Electricity and Magnetism
  • Tutorials
  • Undergraduate projects

Science Communication

I give talks to teachers and school groups about my research and astronomy in general and lead an initiative to provide undergraduate science interpreters for the National Space Center.

Professional Activities

I am chair of the STFC Astronomy Advisory Panel. Projects I am involved in include: member of the executive committee for the Swift satellite; co-Investigator on the SVOM satellite; member of the UK LOFAR board; member HESS-2 GRB working group; co-chair transient working group of the Athena mission; co-investigator on the Chinese advanced study project for the Einstein Probe mission; member science user group of CTA.

Administrative Duties

Head of Department. Chair Department Research Committee. Member National Space Park Delivery Group. Member Board of Leicester Institute of Space and Earth Observation. Member College Leadership Team. Member University Executive Board. Member University Senate. Member University Council.

Selected Recent Publications

  • Nardini E., et al., Black hole feedback in the luminous quasar PDS 456 Science (2015) 347:860-863 (Journal article) DOI for this publication
  • Levan A. J., et al., A New Population of Ultra-long Duration Gamma-Ray Bursts The Astrophysical Journal (2014) 781:13- (Journal article) DOI for this publication
  • Reeves J. N., Braito V., Gofford J., Sim S. A., Behar E., Costa M., Kaspi S., Matzeu G., Miller L., O'Brien P., Turner T. J., Ward M., Variability of the High-velocity Outflow in the Quasar PDS 456 The Astrophysical Journal (2014) 780:45- (Journal article) DOI for this publication
  • Gompertz B. P., O'Brien P. T., Wynn G. A., Magnetar powered GRBs: explaining the extended emission and X-ray plateau of short GRB light curves Monthly Notices of the Royal Astronomical Society (2013) 438:240-250 (Journal article) DOI for this publication
  • O'Brien P. T., Smartt S. J., Interpreting signals from astrophysical transient experiments Royal Society of London Philosophical Transactions Series A (2013) 371:20498- (Journal article) DOI for this publication
  • Inoue S., et al., Gamma-ray burst science in the era of the Cherenkov Telescope Array Astroparticle Physics (2013) 43:252-275 (Journal article) DOI for this publication

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