Measuring Dark Matter, Neutral Hydrogen and Neutrino Mass with Next Generation Weak Lensing and Radio Data

My research aims at measuring fundamental properties of three extremely elusive substances: dark matter, dark energy and neutrinos. As recently discovered, neutrinos are massive particles (Nobel Prize 2015), but their actual mass is still unknown. While we now understand how dark matter interacts with gravity, we still do not know what it is, and different cosmological measurements disagree about its abundance. Furthermore, all aspects of the dark energy are highly uncertain.

This situation will change drastically with the upcoming generation of galaxy surveys such as Euclid, LSST and WFIRST. These dedicated observatories will measure properties of dark matter, dark energy and neutrinos based on their "weak gravitational lensing" signatures. This technique relies on the detection of small distortions imparted on the image of distant galaxies by the gravitational pull of foreground massive objects. Weak lensing measures the abundance and the clustering of the total foreground matter, which is uniquely affected by its different elements.

I will use the latest observations from the Kilo Degree Survey, which has started to deliver exquisite weak lensing data, and will push the frontiers of our knowledge about the Universe, its content and its initial conditions. Through combining these dark matter data with independent observations of the cosmic microwave background and of the hydrogen, I will map out the global content of our Universe, component-by-component. This will be achieved with the method of 'cross-correlations', which singles out species common two both datasets.

These are transforming times for the field of cosmology, and the fundamental research undertaken during this Fellowship will by central to our understanding of dark matter, neutrinos, hydrogen and dark energy.

The expected outcome of the research includes the combined analyses of two lensing data sets, cosmic microwave background observations, and three dimensional maps of neutral hydrogen. It will result in at least five first-authored papers, plus a number of contributions based on sharing the simulations products that will be produced. This will directly support the future analysis of a number of scientific investigations, aiming for an impact well beyond 2030.