Promotor: K. Kuijken, Co-Promotor: H. Hoekstra

Of all the mass in our Universe, 80% is thought to consist of a hypothetical and invisible substance called dark matter (DM).

Galaxy intrinsic alignments induce a major astrophysical contamination to weak gravitational lensing measurements and need to be modelled and mitigated when extracting cosmological information from such measurements.

Galaxies form and live inside dark matter haloes. As a consequence, they are exposed to the tidal fields generated by the surrounding matter distribution: this imprints a preferential direction to the galaxy shapes, which leads to a coherent alignment on physically close galaxies, called intrinsic a…

This thesis investigates the structural evolution and assembly of galaxies since the first few billions years after the big bang.

Promotor: Koen Kuijken Co-promotor: Henk Hoekstra

Many astronomers suspect that most of the matter in the universe is invisible. So how can you weigh dark matter if you can't actually see it? Professor Henk Hoekstra is looking for a solution. Inaugural lecture 25 June.

Promotor: Prof.dr. J. Schaye, Co-promotor: Marcello Cacciato

ESA’s Euclid mission is to reveal the dark side of the Universe. But how? Professor of Observational cosmology Henk Hoekstra explains it in his interview with Space Team Europe and Horizon Magazine. He uses enlightening examples such as… a swimming pool! Listen to Henk Hoekstra to understand how Euclid…

Leiden Observatory is going to use a new technique to carry out calculations on gravitational lensing measurements. They will do this is the context of research into the formation of elliptical galaxies. Alessandro Sonnenfeld (University of Tokyo) who developed this technique joined the research team…