Date: Saturday 15th October | Time: 2.15pm  – 3.15pm


Professor  Nial Tavir

Professor of Astronomy  University Of Leicester

Nial obtained a BSc in Mathematics and Physics at the University of Durham and stayed on there to do a PhD, working on problems of the extragalactic distance scale.  After a short post-doc in Durham, Nial moved to the Institute of Astronomy in Cambridge where he continued to work on the distance scale, as well as expanding to other areas, including investigating the nature of gamma-ray bursts.  In 1999 he was appointed as a lecturer at the University of Hertfordshire, and in 2006 moved to the University of Leicester as Professor of Astronomy. His research interests have continued to evolve, and he has made notable progress in the use of gamma-ray bursts to probe the very distant universe, and in opening up the new field of multi-messenger astrophysics. In 2002, Nial was the co-recipient of the European Union Descartes Prize, recognising pioneering contributions to the study of gamma-ray burst afterglows, and in 2019 he was awarded the Royal Astronomical Society’s Herschel Medal for his investigations of the explosive universe.

Lecture synopsis

 What reionized the universe? Clues from the most powerful explosions.

At some point in the first few hundred million years after the Big Bang, the bulk of the gas in the universe – the tenuous hydrogen that is spread between the galaxies – turned from being neutral to being almost entirely ionized. It is widely thought that ultraviolet radiation from early generations of massive stars led to this key cosmic event, but it remains far from clear how reionization proceeded, and indeed, whether sufficient radiation was produced by stars to do the job. Long-duration gamma-ray bursts are extreme explosions produced by the deaths of some massive stars, and thanks to their immense luminosity, provide unique clues to the nature of the early stars and galaxies and their part in reionization.