Time-domain astronomy is now entering its golden age. Modern sky surveys find thousands of transients—sources that suddenly appear then fade forever—every year. This is revolutionising our understanding of the dynamic Universe and stellar evolution, revealing unexpected and energetic channels by which stars can end their lives. Simultaneously, we have begun to probe the gravitational sky, thanks to the remarkable success of Advanced LIGO and Virgo. The most valuable transients are those which are poorly understood, since by definition they have
the most to teach us about physical processes in new regimes. Unsurprisingly, these tend to be the rarest events that have been difficult to study historically. For such objects, each additional event adds a new piece to the puzzle.
Three types of rare transient events in particular offer wide-ranging perspectives on how compact objects (black holes and neutron stars) influence stellar death, and on the physics of the compact objects themselves:
Kilonovae are the radioactive glows from new heavy elements created by the collision and merging of neutron stars in a close binary system. These also produce gravitational waves, and are so far the only sources in the Universe detected in both electromagnetic and gravitational emission. Understanding the physics of these explosions gives unique insight to the creation of about half of the periodic table, as well as the behaviour of sub-atomic particles above nuclear densities.
Superluminous supernovae are the brightest explosions in the Universe and point to missing physics in our understanding of stellar evolution. They may be powered by the rotation of fast-spinning, magnetic neutron stars formed during the collapse of their stellar cores, allowing us to understand compact object formation and the evolution of the most massive stars.
Tidal disruption events are flares from stars shredded by supermassive black holes. They can reveal how black holes grow in the centres of galaxies, and help to untangle the very complicated physics of astrophysical accretion disks. Each of these populations has only a few tens of known examples, and in the case of kilonovae only a handful.
The goal of this project is to capitalise on the unprecedented power of wide-field telescopes combined with Data Science and Machine Learning approaches, to discover, follow up and analyse large samples of these rare explosions.
