Weak gravitational lensing with the Euclid mission

This project addresses the STFC challenges A3, "how is the universe evolving and what roles do dark matter and dark energy play?", C4, "what is the nature of dark matter and dark energy?" and A7, "what is the true nature of gravity?".

The project aims to prepare for the analysis of weak lensing data from the ESA and UKSA-funded Euclid mission, in particular the weak lensing data. It particularly focusses on the role that systematic errors will play in the analysis, and looks at how telescope modelling errors would propagate into possible biases in the cosmological analysis. It uses state-of-the-art approaches to telescope modelling and propagation of errors and biases, and will be a key "end-to-end" analysis of this key cosmology probe.

Work will be carried out in collaboration with and as part of the Euclid Consortium.

Measurements of weak gravitational lensing are one of the key ways of testing the standard cosmological model and the accuracy of general relativity on cosmological scales. The European Space Agency's Euclid mission will break new ground in making accurate measurements over about one-third of the entire sky. But to achieve that, we must first accurately model the distorting effect of the Euclid telescope, and at Oxford we have been leading the effort to model the telescope and correct the lensing measurements. Euclid is due launch in 2022 and the survey will take five years to complete. The D.Phil student will work on the modelling and shear measurement, including analysis of the first in-orbit calibration measurements, and should have access to the first of the exciting new survey data to be obtained. The work will involve using scientific programming and simulations to test and improve our physical models of the telescope and its detectors, plus statistical analysis of observational data, and the student should have a role in the first analyses of the early data from the mission.