In this thesis we investigate cosmology and the large scale structure of the Universe using cosmological simulations.

This paper critically compares seven widely used risk assessment tools for violent extremism, including the VERA-2R, the ERG 22+, the SQAT, the IR46, the RRAP, the Radar, and the VAF.

In this thesis, we present new laboratory data of interstellar dust analogues.

Two teams of astronomers, including one from Leiden University, have discovered oxygen in the most distant known galaxy, JADES-GS-z14-0. This groundbreaking discovery shows that galaxies could form much faster in the early universe than was previously thought.

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

Promotor: K.H. Kuijken

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

No more lectures and exams for the Radio Astronomy course taught by Michiel Brentjens. The corona crisis is a moment of reflection that has changed his whole way of teaching. Instead of being in front of the class, he lets his students build a radio telescope with paint cans.

An international team of astronomers, with researchers at Leiden Observatory playing a leading role, has mapped the fuel for galaxy formation in the iconic Hubble Ultra Deep Field. The results of the research have been accepted for publication in The Astrophysical Journal.

Over a seven year period an international team of scientists has mapped more than a quarter of the northern sky using the Low Frequency Array (LOFAR), a pan-European radio telescope. From Leiden, Astronomer Timothy Shimwell and Huub Röttgering, among others, are involved. It reveals an astonishingly…

In 2018, astronomer Jorryt Matthee won the C.J. Kok Jury Prize for the best dissertation of the Faculty of Science. He succeeded in finding a number of rare galaxies from the early Universe. One of them received the same initials as football player Cristiano Ronaldo: CR7.

Radio New Babylon, to be heard around Anna van Beurenplein, Den Haag, from 1-10-2021 onwards, is a collection of sound works by local and international artists inspired by the work of Constant Nieuwenhuys, and developed in the context of the Interdisciplinary Research Group (ACPA, KC, KABK).

Galaxies in the early universe are shrouded in a kind of mist: a cloud of hydrogen. With galaxies in the later universe this mist has disappeared. Astronomer Jorryt Matthee has made the first images of this dissipating mist. PhD defence 19 September.

How do galaxies form? That is what astronomer Mariska Kriek will be researching in the coming years. She received an NWO Vici grant of 1.5 million euros to study galaxies in the early universe. ‘This research uses new and unprecedented observations from the James Webb Space Telescope (JWST). These allow…

Researchers have discovered the most distant Milky-Way-like galaxy yet observed. Dubbed REBELS-25, this disc galaxy seems as orderly as present-day galaxies, but we see it as it was when the Universe was only 700 million years old. This is surprising since, according to our current understanding of…

An international team of astronomers has discovered a large reservoir of hot gas in the cluster-in-formation around the Spiderweb Galaxy. Based partly on that hot gas, the astronomers predict that the cluster-in-formation will grow into one of the largest objects in the universe. A step closer to discovering…

Last Saturday, Reijer Passchier was a guest on one of his favourite radio programmes: Dr. Kelder en Co.

The LOFAR radio telescope produces petabytes of data every year. Radio Astronomers use complex multi-step pipelines to process this data and produce scientific images.

SEO Amsterdam Economics and Leiden University’s Company Law department and Labour Law and Social Security department are to conduct an implementation assessment on the Dutch Whistleblower Protection Act (Wkb) on behalf of the Dutch Ministry of the Interior and Kingdom Relations.

ESA’s Gaia mission has produced the richest star catalogue to date, including high-precision measurements of nearly 1.7 billion stars and revealing previously unseen details of our home Galaxy.

The shock wave triggered by one of the five galaxies making up the iconic Stephan’s Quintet appears to be less disruptive than previously thought, with the shock likely being cushioned by dust particles in the surrounding gas. This is according to the analysis of the first scientific observations of…

Finally we know for sure that there is a black hole at the centre of our own galaxy. Today, astronomers unveiled the first ever photo of Sagittarius A*, a super-massive object at the centre of the Milky Way. This picture could only be taken thanks to the cooperation of telescopes worldwide.

An international team of astronomers led by Dutch scientist Martijn Oei has discovered the largest pair of jets from a black hole ever seen. The 'jumbojets' extend a combined length of 140 Milky Ways. The Leiden Observatory played a prominent role in this research. The publication will feature on the…

Astronomers at ASTRON and Leiden University have used the LOFAR radio telescope to discover a 'brown dwarf' – a faint object more massive than Jupiter, but significantly less massive than the Sun. The discovery of the object dubbed Elegast, opens up a new path that uses radio telescopes to discover…

Promotor: W. Jaffe, Co-promotor: K. Meisenheimer

Tracing the evolution of the molecular gas content in galaxies is critical for a complete understanding of galaxy formation and evolution, as it provides the direct fuel for star formation. Studies of high-redshift (z>1) molecular gas reservoirs, most commonly traced by carbon monoxide (CO), have seen…

On 25 April 2016, Suliman Ibrahim, Senior Researcher at the VVI, was a guest expert on the weekly radio program: 'Huna Libya', a joint initiative by the Libyan al-Wasat Radio and Radio Netherlands Worldwide (RNW).

The publication in Nature Ecology & Evolution about the so-called Siberian unicorns took centre stage in a Dutch radio interview.

In an interview with Sveriges Radio, Sweden’s national radio station, Jorrit Rijpma, Professor of European Law, spoke about European legislation concerning migration.

This is an Erasmus+ International Credit Mobility project of Leiden University’s Faculty of Science with two Nigerian universities, the Center for Basic Space Science and University of Nigeria.

Physicist Joost Frenken was interviewed on the radio show 'Langs de Lijn en Omstreken' (Radio 1) about the recent discovery of superconductive graphene. The one-atom-thick material was already known for its strength, flexibility, lightweight and good conductivity.

BNR Radio has broadcast an item on the physics formulas that are painted on walls across the Leiden historic city center. The wall formulas are initiated by Sense Jan van der Molen and Ivo van Vulpen.

The recent trade dispute between the U.S. and China has renewed the attention for the dependency of the U.S. and many other developed countries on the imports of critical materials. Recently this has led to an initiative by the U.S. government to team up with resource rich countries like Australia and…

On Tuesday June 14th, Dr. Armin Cuyvers of Leiden Law School discussed the legal consequences of a possible Brexit in the radio program Juridische Zaken (Legal Matters) of Business News Radio (BNR).

Associate Professor Erik Bähre talks about the upcoming elections in Brazil on the Dutch Radio channel BNR Radio.

Somali archaeology in Somaliland takes centre stage in a BBC World Service radio programme and a China Global Television Networks (CGTN) programme, both presented by archaeologist Sada Mire.

An extraordinary encounter took place in 1911. American scientists discovered the last 'wild' Indian, from the Yahi tribe, who had lived in total isolation for years. As he had no name, they called him Ishi. But who was this man, and what did this discovery mean to us? Cultural anthropologist Erik Bähre…

Researchers have discovered oxygen in the furthest known galaxy JADES-GS-z14-0. Leiden astronomers Sander Schouws and Rychard Bouwens were part of the team that made this discovery. This news was reported in all newspapers and online media.

An international team of researchers led by astronomers from Leiden University (the Netherlands) has produced the first sharp radio maps of the universe at low frequencies. Thanks to a new calibration technique, they bypassed the disturbances of the Earth's ionosphere. They used the new method to study…

Simulations of galaxy formation provide much more information about galaxies than a telescope. Simulations have been improving significantly in recent years. Astronomer Evgenii Chaikin made such a significant contribution to this field that he graduated with honours on February 27th.

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.

A mother who is far from the romantic ideal image of the mother as we know is the murderous mother. Genevieve Lhermitte, the mother who killed her 5 children, or the neurosurgeon who killed her 14-year-old daughter whose trial recently ended are examples of shocking stories. It goes against every thought…

Tanja Masson-Zwaan, an assistant professor at the Institute of Air and Space Law, spoke on Friday 14 April about space mining on BBC Radio.

In Indonesië zijn studenten massaal in opstand gekomen tegen de regering, die vlak voordat er straks een nieuw parlement aantreedt, nog snel een aantal nieuwe wetten wil doorvoeren.

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

Joris Larik was interviewed by BBC World Service radio on the state of Brexit negotiations, the Irish border issue and ongoing Dutch preparation.