Astrophysics at the University of Bath 2023-2026

Using sophisticated theoretical modelling and groundbreaking observations from the world's most powerful telescopes, Bath astrophysicists examine the inner workings of our 'dynamic Universe'. Their explorations serve to reveal the physics underpinning the rich phenomenology of astrophysical sources that vary real-time on the sky, from extreme relativistic transients to variable stars that anchor the cosmological distance ladder. Their studies equally encompass the evolutionary paths and cycles that play out over billions of years, giving rise to the growth of galaxies, the chemical enrichment of their gas reservoirs, and the emergence of supermassive black holes at their centres.

This consolidated grant will enable early career researchers to work jointly with the astrophysics staff at the University of Bath to advance these areas of research, to share the scientific findings and the resources to (re)produce them with the global astronomical community, and to inspire the next generation of scientists via public engagement activities directly rooted in the proposed cutting edge research.

The proposed projects are timely, motivated by and making use of a new generation of observational facilities that will transform many facets of astronomy. The first successes in multi-messenger astrophysics, including contributions from Bath, are still very fresh, but already our theorists are looking ahead and developing the models and tools that will enable an improved interpretation of new electromagnetic counterparts associated with gravitational wave signals, and that will prepare the community for upcoming SKA observations. Among phenomena studied are flares originating from the shattering crusts of merging neutron stars, and relativistic jets propagating through and interacting with the circumstellar material surrounding the most luminous explosions in the Universe. The theory developed will shed light on Nature's densest objects and most energetic events.
Bath astrophysicists will also be among the first observers with the newly launched James Webb Space Telescope. JWST will provide a sensitive view in emission of the early chemical enrichment in galaxies, complementary to what was gathered previously by the imprint of metal absorption features seen against the bright background light of gamma-ray burst afterglows piercing through the gas reservoir of distant galaxies. This uniquely enables a long due calibration of metallicity diagnostics, and will inform subgrid recipes in galaxy simulations.
Finally, Bath astrophysicists will push the frontiers of wide-area astronomy by using soon-to-be commissioned highly multiplexed spectrographs (e.g., 4MOST, MOONS) and imagers (e.g., Rubin-LSST) to collect samples of unprecedented size and probes of galaxy environments of unprecedented accuracy. These facilities will introduce a revolution in data-driven science, through which the team at Bath will characterize the group dark matter halos against which the luminous side of galaxy evolution unfolds, shedding light on how galaxy growth is affected differently by in-situ physics vs environmental factors. They will leverage these resources to study the interplay between supermassive black holes and their host galaxies, addressing how galaxy - black hole coevolution operates differently at distinct levels of obscuration. Finally, a holistic calibration of different types of Cepheid variable stars as standard candles, folding in constraints on not just period and luminosity, but also colour and metallicity, will remove biases in the cosmological distance ladder, and will address one of the biggest questions of them all: is our standard cosmology the full story?

By harvesting the science newly enabled by this array of new observatories and instruments, the proposed programme will yield an immediate return on significant UK investments into these international facilities.