Professor Paul O'Brien

photoProfessor of Astrophysics and Space Science

Room G19, Physics & Astronomy Department

Tel: +44 (0)116 252 5203


Personal details

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

I began my career at University College London, obtaining a BSc in Astronomy. I then obtained a PhD in Astronomy at UCL on the Ultraviolet Emission from Quasars.

I 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.

I moved to the University of Leicester as a lecturer in 1996, and am now a Professor of Astrophysics and Space Science in the Physics and Astronomy Department.


Professional activities

Projects I am involved in include:

  • member of the executive committee for the Swift satellite
  • co-Investigator on the SVOM satellite
  • lead of SXI instrument on THESEUS mission
  • member of the GOTO project
  • member of the HESS-2 transients working group
  • co-chair of the transient working group of the Athena mission
  • member of the science user group of CTA


I teach on these courses:

  • PA1130 Electricity and Magnetism
  • PA1720 Mathematical Physics
  • Physics challenge
  • Tutorials
  • Undergraduate projects

Administrative duties

  • Member Department Equality, Diversity and Inclusion committee


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.
  • Identifying the electromagnetic counterparts to gravitational wave and neutrino sources. This is the field of research called "multi-messenger astrophysics". The sources involve include GRBs and other explosive transients. The search is challenging due to the (usually) large error regions from GW and neutrino observatories which must then be searched. Rarely, there may be a joint trigger, as happend for GW170817.
  • 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 several new missions, including SVOM, Einstein Probe, THESEUS, and Athena, and I 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 and the GOTO project to provide wide-angle optical monitoring of the sky.


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.

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Contact Details

Tel.: +44 (0)116 252 3506
Fax: +44 (0)116 252 2770

Department of Physics & Astronomy,
University of Leicester,
University Road,
Leicester, LE1 7RH,
United Kingdom.


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