Beyond Ultra-Faint: revealing dark-matter rich globular clusters in the local universe

Wide-field surveys have revealed the remarkable complexity of the faint Universe, uncovering ultra-faint dwarf galaxies and star clusters that push the limits of known stellar systems. Ultra-faint dwarfs, with luminosities below a thousand Suns, are likely relics of the earliest galaxies and are dominated by dark matter. Meanwhile, extended clusters (ECs)—first identified in Andromeda in 2005—occupy nearly the same region of parameter space, but their true nature remains unresolved. Recent work further predicts a new class of objects, globular clusters formed within their own dark matter mini-halos (GCDs), which overlap observationally with the EC population. Distinguishing these systems is essential for testing models of dark matter, particularly as upcoming facilities such as Euclid and the Vera Rubin Observatory probe ever fainter and more distant populations.

This PhD project aims to: (1) definitively determine the nature of Andromeda’s ECs using new Keck IFU spectroscopy and deep Hubble imaging, providing the first decisive constraints on their dark matter content and star-formation histories; (2) investigate newly identified GCD candidates using archival data and simulations to confirm or rule out mini-halo hosts; and (3) apply machine-learning classification to Euclid data to map ECs across the Local Volume and place them in a cosmological context.

You will need to meet the minimum entry requirements for our Physics PhD programme.

Open to candidates who pay UK/home rate fees. See UKCISA for further information.