My research focuses on testing the fundamentals of our cosmological model and thereby helping to find an answer to some of the major open questions in physics: How did structure in the Universe form and evolve, and what role does dark matter play in this? What is the cause of the recent accelerated expansion of the Universe? And is Einstein's theory of gravity still correct on the largest cosmological scales?
To this end I contribute to developing, running, and analysing some of the largest current and forthcoming deep galaxy surveys:
The ESO Kilo-Degree Survey
Conducted at Paranal Observatory in Chile together with its infrared sister survey, VIKING, KiDS has provided high-quality imaging and 9-band photometry ideally suited for measuring the weak gravitational lensing effect by the large-scale structure of the Universe. I am part of the core team that produces the KiDS cosmology results.
The ESA Euclid Mission
A space telescope to be launched in 2022, Euclid is designed to provide extremely stable imaging and infrared photometry and spectroscopy in exquisite quality that can only be done in space. I am deputy lead of the Organisational Unit that produces the final data products in the Euclid Ground Segment, and hold several other positions in the Euclid Consortium.
The PAU Survey
The PAU Survey at the William Herschel Telescope at La Palma Observatory fills the niche between spectroscopic and imaging galaxy surveys by taking deep images in 40 narrow passbands. This provides low-resolution spectra for all objects in the field of view, which our survey team uses to explore the galaxy-dark matter connection and help calibrate larger cosmology surveys.
The Legacy Survey of Space and Time
Currently under construction in Chile, the Rubin Observatory will accumulate very deep multi-band imaging over the full Southern extragalactic sky during the 2020s with its flagship LSST survey. I am active in the LSST's Dark Energy Science Collaboration, with main interests in enabling the analysis of large-scale structure probes and the synergies with Euclid.