I am Professor of Cosmology at the Institute of Cosmology and Gravitation. My research area is observational cosmology – this means I study the properties of dark energy, dark matter and gravity, using the large-scale structure of the Universe and based on galaxy survey data collected by the leading ground-based and space telescopes.

My research has been funded by the Science and Technology Facilities Council (STFC), the UK Space Agency (UKSA), and the European Commission.

I study the large-scale structure of the Universe, analysing the statistical patterns in the distribution of millions of galaxies to uncover cosmological information. I am particularly known for my work on baryon acoustic oscillations and the development of new methods beyond two-point clustering statistics, such as cosmic voids or density-split statistics. More generally I have worked on a wide range of other areas in cosmology, including redshift-space distortions, clustering of the Lyman-alpha forest and gravitational lensing, as well as theoretical models of dark matter, dark energy and inflation.  

A large fraction of my work involves the Dark Energy Spectroscopic Instrument survey, or DESI. DESI is a 8-year spectroscopic survey programme to map the positions of 60 million galaxies and quasars in order to determine the dark energy equation of state, the neutrino mass scale, and a host of other science results. I led the Galaxy and Quasar Clustering working group in DESI from 2022-2025, when we published our major results from the first two data releases.

Another large part of my work is within the Euclid Consortium. Euclid is a space telescope, which combines spectroscopic measurements of around 30 million galaxies with weak lensing and photometric surveys of over a billion. I lead a UKSA-funded group at Portsmouth creating the spectroscopic galaxy catalogues and visibility mask for Euclid clustering science, and coordinate a DR1 Key Project on measuring baryon acoustic oscillations.

In the past I also worked on the extended Baryon Oscillation Spectroscopic Survey (eBOSS) and the Dark Energy Survey (DES).

I am available for media requests, interviews and comments on astronomy- and cosmology-related stories. My previous contributions include appearances on The Sky At Night, a BBC4 documentary with Hannah Fry, and interviews with the Guardian, Observer, Nature, Scientific American and others.

I also give public lectures about cosmology in science festivals and meetings in the local area.