A&G Highlights Meeting - October 2025

A&G Highlights Meeting Programme - 10th October 2025

Dr Rob Eyles-Ferris

'Trapped jets and fast X-rays from the deaths of massive stars'

The deaths of massive stars or collapsars can power the most powerful explosions in the universe - gamma-ray bursts or GRBs. As the star collapses, it forms a black hole and material from the star is fired out at speeds close to the speed of light in a relativistic jet. These jets produce the GRB itself and a longer-lived afterglow across the electromagnetic spectrum followed by a supernova as the stellar material radioactively decays. The recent launch of Einstein Probe has shown that similar collapsar events can also produce fast X-ray transients (FXTs) which resemble GRBs but at much lower energies. I will discuss an FXT detected at the start of this year, EP250108a, which has unveiled some of the physics underlying these events. In particular, a fast blue optical precursor to the supernova has shown that in this case, the collapse did produce a jet but it was trapped by the outer layers of the star or the material surrounding it. Comparisons to other FXT-supernovae show that there is a broad spectrum in how these jets behave and I will discuss how Einstein Probe is finally allowing us to discover them.

Rob Eyles-Ferris is a research associate at the University of Leicester who works on high energy transients to understand the largest explosions in the universe. His particular research interests include tidal disruption events, fast X-ray transients and gamma-ray bursts.

Dr Niall Jeffrey - Winner of the Early Career Award (A)

'What has AI ever done for us? – Learning about dark energy from maps of dark matter'

The nature of dark energy is encoded in the cosmic web of dark matter in the Universe. Using new AI techniques, we can unlock this. I will present the latest results from the Dark Energy Survey which use the gravitational lensing effect to create maps of dark matter, from which we can learn about dark energy. I will also contrast our AI approach with common perceptions of AI, showing that we employ robust scientific methods that require the development of new techniques – this set of techniques is known as "simulation-based inference". Looking forward, I will explore the excitement and the challenges that lie ahead in the era of the Euclid space mission.

Niall Jeffrey - PhD UCL 2019, followed by a research position at the Ecole Normale Superieure, Paris. Currently a Senior Research Fellow at UCL.

More TBC