I am a Hintze Fellow, an independent research fellowship, in the Department of Astrophysics, University of Oxford and part of the Beecroft Institute for Particle Astrophysics and Cosmology. My research focuses on the nature of dark matter. In particular, I study the statistical relationship between luminous galaxies and their underlying dark matter halos — the so-called galaxy–halo connection. My work aims to bridge two complementary approaches: our cosmological understanding of halo populations derived from the standard model of cosmology and large-scale galaxy clustering surveys, and direct dynamical probes on smaller scales, including stellar and gas kinematics and weak gravitational lensing. A central goal is to test whether the dark matter halos predicted by ΛCDM are consistent with these small-scale observational signatures (e.g. https://arxiv.org/abs/2601.07799).
Dark matter is an extremely challenging problem. Gravity, possibly our only probe, is intrinsically weak, while the luminous matter we can observe is only a small fraction of the mass. Each inference is therefore both noisy and model-dependent, and no single dataset provides strong constraints on the halo population. A major theme of my research is the development of Bayesian frameworks that combine heterogeneous datasets in a unified statistical model, while propagating the many uncertainties associated with different dynamical tracers (e.g. https://arxiv.org/abs/2206.15443).
Finally, because our theoretical priors on the microphysical nature of dark matter remain weak, and because observations on small scales appear to be in tension with the simplest halo predictions of standard cosmology, I develop machine learning methods that allow for greater flexibility and fewer structural assumptions. These approaches enable non-parametric tests of the dark matter distribution, with the aim of learning its phenomenology directly from the data rather than imposing restrictive halo models a priori (e.g. https://arxiv.org/abs/2508.03569, https://arxiv.org/abs/2601.05203).
Current students
Navdha - Constraining the nature of dark matter with Euclid, Rubin and MeerKAT (PhD, Oxford, 2026–; with M. Jarvis, H. Desmond)
Alicia Martín — Empirical dark matter halo profiles with symbolic regression (PhD, Oxford, 2022–; with D. Bartlett, H. Desmond, P. Ferreira)
Fedir Boreiko — Light–dark matter correlation across cosmic time (MSc, Manchester, 2024–; with A. Ponomareva, R. Stiskalek, H. Desmond)
Enoch Koh — Dark matter dynamics: enduring puzzles (MSc, Warwick, 2024–; with H. Desmond, R. Stiskalek)
Alexandra Cheytanova — Galaxy–filament alignments (MPhys, Oxford, 2025–; with L. Jung)
Noah Pierce — Testing cosmic homogeneity (MMathPhys, Oxford, 2025–; with H. Desmond, R. Stiskalek)
Former students
Catherine Spencer — Cosmic web environment and galaxy properties (MSc, Oxford, 2023–2025; with R. Stiskalek, H. Desmond)
James Harvey — Galaxy merger histories via machine learning (MSc, Oxford, 2023–2024; with R. Stiskalek, H. Desmond)
Sophie White — Improving photometric redshifts with Gaussian processes (MSc, Birmingham, 2024; with M. Jarvis)
Adi Naik — Causal inference in astrophysics (MSc, Southampton, 2024; with H. Desmond)