Stars end their lives in many ways. Some fade away, others explode. More rarely they may collide with another star, or be torn apart by the strong gravity from a black hole. It is an irony of stellar evolution that many stars are actually at their brightest at the moment of their death, creating signatures which can be seen at great distances – much further than the star could be seen during its life. This means that stellar death provides a unique window both into the nature of the stars and their evolution, but also into the extreme physics which acts upon them at the moment of their demise. The extreme brightness of these stellar deaths also means they can be used as lighthouses to probe the distant Universe.
This ERC project focussed on understanding the nature of stellar deaths which are powered by a compact object (usually a neutron star or a black hole) that resides at the centre of the explosion. The energy released from this central engine can transform the explosion, making it brighter than it may otherwise be or allowing other extreme physical processes, such as the synthesis of heavy elements, to occur. The aim of this project is to understand how these central engines impact explosions, from their observational appearance to a test of the ubiquity of black holes in galaxies, to a route to testing the origin of the heaviest elements.
Core results from the grant include:
1) The discovery of the first electromagnetic counterparts to gravitational wave sources
2) The identification of kilonova in long-duration gamma-ray bursts, demonstrating a hitherto unexpected origin
3) The first James Webb Space Telescope observations of long duration gamma-ray bursts
4) The discovery of new forms of tidal disruption event, both relativistic and thermal
5) The discovery of the first gamma-ray burst formed by dynamical processes (collisions) in the dense nuclei of galaxies
6) Studies of the brightest gamma-ray burst of all time.
