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

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.

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

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.

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.

De Universiteit Leiden houdt haar drinkwaterverbruik zo laag mogelijk.

Promotor: M.T.M. Koper, Co-Promotor: L.B.F. Juurlink

Water is all around us and is vital for all aspects of life. Studying the various compounds and life forms that inhabit natural waters lets us better understand the world around us.

The International Course on Water Use and Management in Cagayan Valley The Philippines (2011-2015)

To design the ideal water oxidation catalyst, understanding of the catalytic mechanism and decomposition pathways is essential.

Astronomical observations of cold regions in the universe show a rich inventory of ices. Part of these ices may end up on planets like our own, but in that journey they will be exposed to considerable amounts of radiation.

While ecosystems have concrete benefits for human society, these benefits are typically overlooked in decision-making.

This thesis examines the impacts and challenges of water use of electric power system. This thesis found that there are large differences in water use of electricity technologies, with hydropower and thermal power being two large water users.

Nederland telt een achttal echte eilanden, of negen als ‘Rottum’ (Rottumeroog en Rottumerplaat) voor twee wordt gerekend. Daarnaast zijn er zeventien voormalige eilanden, waar de sfeer van vroeger nog voelbaar is. Jan Bank en Doeko Bosscher, fervente eilandliefhebbers, onderzoeken de geschiedenis van…

Op 18 januari is de studie ‘Stille wateren hebben diepe gronden – Een analyse van de inkomensverdeling en haar determinanten over de afgelopen veertig jaar’ verschenen. Op deze website kunnen de studie en het achterliggend cijfermateriaal geraadpleegd worden.

Before the large scale use of renewable energy sources can be implemented in our society, the storage of electrical energy needs to be tackled. Storage the energy as hydrogen via the reduction of protons is a good option.

In this dissertation, the synthesis and characterization of a series of iron complexes based on different ligand platforms are described.

In the search for sustainable energy solutions, the idea of artificial photosynthesis has been proposed as an approach with which to use water and sunlight to produce hydrogen.

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.

As a virtually inexhaustible source, solar energy plays a major role in future global energy scenarios.

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

Promotor: M.T.M. Koper, Co-promotor: J.B.F. Juurlink

In this dissertation iron-based homogeneous catalysts were synthesized, characterized and investigated for water oxidation activity.

Producing green energy has become the main goal in our society in the search of reducing or eliminating the carbon emission from fossil fuels.

Promotor: M.T.M. Koper, Co-promotor: L. Juurlink

Climate change is one of the largest challenges faced by humanity. To combat this research into alternatives to fossil fuels is ongoing. Dihydrogen is considered a good alternative fuel, since its burning only forms water.

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.

feestbundel voor de Britse demotisant Cary J. Martin (UC Londen)

Promotor: Prof.dr. M.T.M. Koper, Co-Promotor: F. Calle-Vallejo

Achter de relatief stabiele inkomensongelijkheid in Nederland gaan grote veranderingen schuil. De inkomensongelijkheid is de afgelopen veertig jaar wel toegenomen maar viel vooral minder sterk uit doordat vrouwen in lagere inkomensgroepen meer zijn gaan werken. Ondertussen is het inkomen van mannen…

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.

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.

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

CML rapport 192

Promotor: Koen Kuijken Co-promotor: Henk Hoekstra

Ice, the solid state of water, plays an important role on our planet as well as the entire universe.Despite the fact that an individual water molecule has a very simple structure, its chemical bonding in the solid phase can be surprisingly complex.

Consequences for sediment stability and seston trapping

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.

Een robot trainen in de praktijk: het is eigenlijk niet te doen. Computerwetenschapper en psycholoog Roy de Kleijn stapte over op training in een gesimuleerde, virtuele omgeving. 'Dan heb je wel een reality gap, maar hoe nauwkeuriger je traint, hoe beter het gaat in de praktijk.' Zijn inspiratiebron:…

Promotor: Prof.dr. H.V.J. Linnartz

Op 29 april 2020 verdedigde Beth Van Schaack haar proefschrift 'Imagining Justice for Syria: Water Always Finds Its Way'. Het promotieonderzoek is begeleid door promotor prof.dr. C. Stahn.

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.

Onderzoekers van het Laboratorium voor Astrofysica van de Sterrewacht Leiden zijn erin geslaagd om water te maken onder omstandigheden zoals die in de ruimte heersen.

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