The first direct detection of gravitational waves opened the possibility of mapping the Universe via this new and independent messenger.

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

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

One of the most important correlation functions in physics, especially in cosmology, is the energy density, which describes how much energy is present at each point in spacetime due to matter fields. A key contribution to the energy density of the primordial universe comes from gravitational waves (GWs),…

We explored the Universe using weak gravitational lensing, a phenomenon that occurs when light from distant galaxies is bent by the gravitational fields of closer cosmic objects, much like how a lens distorts light.

In this work, I explore the creation of new methods that optimize simulations of the gravitational N-body problem. Specifically, I take advantage of the recent popularity of Machine Learning methods to find tools that can suit this problem.

In astronomy, the interpration of observations and measurements plays a crucial role: we rely purely and fundamentally on the information that reaches us as observers. And 80% of all matter in the universe is undetectable directly.

Promotor: Prof.dr. S. Portegies Zwart

In this thesis we study the landscape of gravitational models which modify GR by introducing an additional scalar degree of freedom (d.o.f.) to source Cosmic Acceleration.

For centuries astronomers studied the Universe by collecting light. Nowadays, we are living in times of great technological advancements, which allow us to explore our Universe in a new way - though gravitational wave radiation.

At the largest scales, two ingredients dictate the distribution of matter in the Universe. The first is dark matter, acting as an invisible scaffolding held together by gravitational forces.

It's one of the big cosmology debates: the universe is expanding, but how fast exactly? Two available measurements yield different results. Leiden physicist David Harvey adapted an independent third measurement method, using the light warping properties of galaxies predicted by Einstein. He published…

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

Leiden University is involved in five new NWO Gravitation projects. Two relate to mental disorder and the remaining three to a healthy lifestyle, the combination of human and artificial intelligence, and the special relationship between plants and microbes.

Three major research projects involving Leiden scientists have been awarded a grant from NWO’s Gravitation Programme. The projects are on innovation processes, organs-on-chips and quantum software.

The project Hybrid Intelligence receives 19 million euros from the Gravitation programme of the Dutch Research Council (NWO). The consortium consists of six Dutch universities and combines human and artificial intelligence, aiming to amplify human intelligence instead of replacing it. Leiden professors…

The physical origin of the dozens of stellar-mass binaries, the mergers of which have been detected by the LIGO-Virgo-KAGRA collaboration via gravitational waves, is still unknown.

The ultimate goal of cosmologists is to find a cosmological model able to explain the current observational data.

The high velocity tail of the total velocity distribution of stars provides essential insight into fundamental properties of the Galaxy.

The Advanced Nano-electrochemistry Institute Of the Netherlands (ANION) consortium will receive 23.6m euros in Gravitation funding for research on important electrochemical processes for energy transition. An additional four consortia with members from Leiden have also been awarded funding.

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.

Three major cosmology-focused missions are planned for the next decade: the Euclid space telescope, the Vera C. Rubin Observatory in Chile, and the Nancy Grace Roman Space Telescope.

Promotor: Koen Kuijken Co-promotor: Henk Hoekstra

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…

In this thesis, the research focuses on the properties of dark matter and dark matter haloes and how they connect with the galaxies we can observe in the Universe.

Professor Frank den Hollander has been awarded a 10-year grant through the NWO Gravitation program, jointly with colleagues from the University of Amsterdam, the Center for Mathematics and Computer Science in Amsterdam, and the Technical University of Eindhoven.

For centuries, astronomers have studied the universe by collecting light signals. Since 2015, the confirmation of an important prediction of Einstein allows us to explore the universe in a new way: through gravitational wave radiation. Astronomy PhD candidate Valeriya Korol proposes to use these gravitational…

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

There are several ways to become a donor to the LUC Fund, both from the Netherlands or abroad.

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: M. de Jong, Co-Promotor: Samtleben

Our research primarily focuses on the early universe and its origins in theories that go beyond the Standard Model of particle physics.

Promotor: P. T. de Zeeuw, Co-promotor: N. Neumayer; G. van de Ven

Over time, the temperature in all buildings will be regulated in a sustainable manner. In this way, using gas will not be necessary anymore.

Promotor: K.H. Kuijken

The Sun and all the stars in the night sky reside in the Milky Way galaxy. In the at-rest reference frame of the Galaxy, typical stars travel with velocities of about 100-200 kilometres per second.

Astronomer and Marxist Anton Pannekoek was a remarkable figure. This book aims to study the connections between his life as a socialist theorist and as a pioneering scientist through the prism of Pannekoek's biography.

What physics controls the properties of quantum matter, such as how electrons flow inside high-temperature superconductors? This question has captivated the physics community and industry for decades, in part due to the great technological potential such materials have, but also because they have resisted…

Welcome to the Hensen Lab! We are a young dynamic experimental research group starting at the Leiden Institute of Physics. Our lab addresses one of the key challenges of modern physics: understanding the interface between quantum mechanics and general relativity.

Improvements of weak gravitational lensing shape measurements are presented and some used for data analysis.

This thesis is dedicated to the exploration of the primordial dark ages: unknown physics during the earliest stages of the Universe’s expansion that have not yet been directly probed by observations. Cosmic inflation is a burst of exponential expansion of space after the “Big Bang”.

Natascha van der Zwan, Assistant Professor at Leiden Univeristy, together with two other authors, wrote a book that explored some of the ways coronavirus is impacting the global capitalist system – and how this could change for better and for worse.

On 12 March, Frederik Heitmüller defended the thesis 'Combatting tax avoidance, the OECD way? The impact of the BEPS Project on developing and emerging countries’ approach to international tax avoidance'. The doctoral research was supervised by Madeleine Hosli and Irma Mosquera Valderrama.

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…

This book is about the workings of networks of the mobile in Africa, a continent usually associated with the ‘global shadows’ of the world.