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

One of the most important puzzles in modern astrophysics is the nature of dark matter.

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

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.

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

Dark matter is one of the biggest mysteries of the Universe. Its properties cannot be explained with the known laws of physics and elementary particles.

Data from 41 million galaxies does not shake up the standard cosmological model after all. To that conclusion, to their own surprise, comes an international team of researchers including Koen Kuijken, professor at the Leiden Observatory.

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.

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…

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.…

Dark matter. Something invisible that, according to calculations, comprises about 85% of the matter in the universe. With an ERC Advanced Grant of €2.5 million, Professor of Observational Cosmology Henk Hoekstra will map out even more precisely where this dark matter is to be found.

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.

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…

CERN has approved the construction and operation of SND@LHC, a neutrino detector at the Large Hadron Collider. It's a precursor for SHiP, a detector meant to detect dark matter. Leiden physicist Alexey Boyarsky is one of the initiators of both SHiP and SND@LHC.

Dark matter represents around eighty per cent of the total mass in the Universe. Yet, we still don't really know what it's made of. Astronomer Pavel Mancera Piña is looking for answers. With a Veni grant from NWO and the most advanced telescopes, such as the James Webb Space Telescope, he will investigate…

By looking at stars in dwarf galaxies research Bas Zoutendijk is trying to gain new insight into dark matter.

Not only dark matter, but also ordinary matter and dark energy are tracked in the largest ever cosmological computer simulation ever. In the FLAMINGO simulations, you can see virtual galaxies and clusters of galaxies emerging over the course of billions of years. This is no easy task: with more than…

He makes music, goes to the athletics track twice a week and, according to his supervisor, has done his research so well that it would not be out of place in a PhD research. Physics and astronomy student Hidde Stoffels' undergraduate research on the properties of dark matter is of such high quality…

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.

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…

Henk Hoekstra and Alessandra Silvestri work on the astronomy and theoretical physics in the Euclid mission. These Dutch researchers are part of the mission.

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.

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

PhD defence

Promotor: Koen Kuijken Co-promotor: Henk Hoekstra

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”.

Lecture

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.

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.

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

In this project, we use social network analysis to analyze the behavior of users in online forums and associated marketplaces over time.

This thesis discusses the discovery potential of Intensity Frontier experiments.

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.

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

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.

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.

What are the mysteries behind soft condensed matter?

From a new generation of antibiotics and more-effective vaccines to a map of dark matter and new light on Hindu traditions. Four researchers from Leiden University have received a prestigious €2.5m ERC Advanced Grant to develop their research.

Research groups in the Quantum Matter & Optics programme investigate electronic properties of matter and light-matter interactions with emphasis on quantum information.

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.

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…

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…

Physicists propose the existence of sterile neutrinos that would explain three big mysteries in nature. To actually find them in particle accelerators, researchers need to know how they are produced and how they decay. PhD candidate Kyrylo Bondarenko has made predictions about this, which are currently…

In this thesis, we show how MRFM can usefully contribute to the field of condensed-matter.