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

Promotor: A. Achúcarro Co-promotor: A. Boyarsky

This thesis is largely an experimental study on the formation of solid-state simple and complex organic molecules in the H2O-rich and CO-rich ice phases of dense interstellar clouds and dark cores.

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

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.

It is an established fact that the Standard Model has to be extended to explain the so-called Beyond the Standard Model (BSM) phenomena: dark matter, matter-antimatter asymmetry of the Universe and neutrino flavour oscillations.

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).

In comparing a selection of 18th-century histories to a representative sample of 19th-century histories of science, this project inquires: Which early modern vices persisted into the 19th century and to what extent were those vices embodied in anecdotes, conveyed through commonplaces, or symbolically…

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.

An international team of astronomers has found an unexpected link between dark matter and visible stars in stellar systems. This discovery may even cause us to reconsider our understanding of gravity. They published on their discovery in 'Nature' on 1 October.

An international team of astronomers, including Professor Koen Kuijken, has published a series of online articles presenting the first results of a major search for dark matter. Never before have researchers been able to chart so precisely the characteristics of groups of galaxies and their dark matter.…

Is our universe built up out of warm or cold dark matter? The standard model assumes cold dark matter particles, but astronomer Sylvia Ploeckinger is now testing the possibility of a warm counterpart: sterile neutrino’s. For this project, she received an NWO Physics/F grant, a special grant for women…

Particle lab CERN gives the green light for the test phase of an experiment that aims to produce dark matter particles. Physicist Alexey Boyarsky is one of the initiators.

Astronomers led by Pieter van Dokkum have discovered a galaxy that barely contains any dark matter, which actually proves that dark matter does indeed exist. The research results will be published this week in Nature.

It must be there. We just cannot see it: mysterious dark matter and dark energy in the universe. Henk Hoekstra is one of the many cosmologists who would love to know what exactly these substances consist of. He has received a European research grant of 1.3 euro million to find out.

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…

An international team of laboratory astrophysicists and astrochemical modellers has shown that glycine, the simplest amino acid and an important building block of life, can form under the harsh conditions that govern chemistry in space. The results have been published this week in Nature Astronomy and…

Spirits play a important role in post-colonial and minority literature as a means of processing black pages from history, according to literary scientist Chia-Sui Lee. PhD defence 11 January.

Astronomer Koen Kuijken and physicist Tjerk Oosterkamp have each been awarded a major subsidy by NWO. The funding will allow them to construct new research facilities.

How can you see something that’s invisible? Well, with Euclid! This future ESA telescope will map the structure of the Universe and teach us more about invisible dark matter and dark energy. Scientific coordinator of Euclid and Leiden astronomer Henk Hoekstra explains how this works.

The theoretical explanation of cosmic acceleration is nowadays one of the biggest puzzles in cosmology.

Geneticist Hans Clevers will give the first Niko Tinbergen lecture new style on 10 December, which is all about stem cells. The young Leiden professors Ariane Briegel and Susana Chuva de Sousa Lopes talk about bacterial noses and the cultivation of egg cells in the lab in short introductory lectures…

A signal that is present both in the centre of our Milky Way and in distant places in the universe could reveal the origin of dark matter. This is what Leiden physicist Alexey Boyarsky concludes in an article in Physical Review Letters.

A glittering visualisation of dark matter by Dutch artist Thijs Biersteker is on display in the Science Gallery at Trinity College Dublin. The installation – ‘Dark Distortions’ – was inspired by Euclid, a forthcoming ESA mission to study the mysterious nature of dark matter. Leiden astronomer Henk Hoekstra…

The centre of our Galaxy is so dark and dense that it is almost impossible to observe what is inside. By catching the rare hypervelocity stars that are ejected from it, Elena Maria Rossi aims to unveil the mysterious environment around the supermassive black hole inside. But she’ll also be solving another…

Exhibition

The master programme was officially opened by H.E. Kees Klompenhouwer – the Ambassador of the Netherlands to the Czech Republic. During his lecture, entitled “Traveling through Europe’s darkness and daylight – A geopolitical Odyssey”, Ambassador Klompenhouwer shared valuable insights on the history…

Promotor: Koen Kuijken Co-promotor: Henk Hoekstra

The focus of the dissertation "Aspects of cosmic acceleration" is the study of possible mechanisms responsible for the late-time accelerated expansion of the universe.

This thesis discusses the discovery potential of Intensity Frontier experiments.

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

What are the 'dark' components of the universe?

Boyarsky is on a quest to unravel the nature of one of the most mysterious phenomena in the Universe. The cosmos appears to consist for the larger part out of mass we cannot see. We have no idea where it comes from. Physicists call this ‘dark matter’. Sterile neutrinos are candidate building blocks…

PhD Defence

PhD Defence

PhD Defence

In the hunt for new particles, physicists look at ever higher energy particle collisions, moving the energy frontier. Some particles however are elusive not due to their high energy, but because they rarely interact. This raises a new barrier: the intensity frontier.

Promotor: Prof.dr. M.K. Richardson

Lecture, Annual Leiden Terra Incognita Lecture

Researchers at Leiden Observatory study the fundamental physics that creates structure in the Universe. These processes collect matter into galaxies and gas into stars. With the use of powerful telescopes and advanced calculations and computer simulations, Leiden astronomers seek to understand the origin,…

Researchers at Leiden Observatory study the fundamental physics that creates structure in the Universe. These processes collect matter into galaxies and gas into stars. With the use of powerful telescopes and advanced calculations and computer simulations, Leiden astronomers seek to understand the origin,…

Lecture

Lecture

In Astronomy, you tackle questions about the universe. What happens in a black hole? What is dark matter? You also apply a great deal of mathematics and physics, and work with computer simulations of planetary orbits, for example.

Physicists, including Dorothea Samtleben from Leiden University, are building a giant underwater telescope to unravel the origin of neutrinos and to solve the mystery surrounding dark matter. The first detector has now been installed. Once it is finished, the telescope will be three cubic kilometres…