A Dutch-Italian-German team of astronomers has observed a huge glow of radio emission around a cluster of thousands of galaxies. They combined data from thousands of LOFAR antennas that were focused for 18 nights on an area the size of four full moons. This is the first time astronomers have been able…

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 more than 200 astronomers from 18 countries has published hundreds of thousands of unknown galaxies. The data are part of a project lead by Leiden professor of Observational cosmology Huub Röttgering. Both Dutch and international media reported extensively about the publica…

Dr Irene Groot (LIC) has been appointed professor of Surface and Interface Science with effect from 1 March. The appointment is an honour for Groot. 'It feels like recognition of your research, teaching and leadership qualities.'

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

This thesis presents pioneering work on the panchromatic emission of some of the most luminous galaxies in the early Universe: star forming galaxies and active galactic nuclei.

An international team of researchers led by Leiden University (the Netherlands) has mapped nine gigantic collisions of galaxy clusters. The collisions took place seven billion years ago and could be observed because they accelerate particles to high speeds. It is the first time that collisions of such…

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…

Media all around the world reported about it: the most detailed images yet seen of galaxies, shot by radio telescope LOFAR. The international team behind these amazing results were led by Leah Morabito at Durham University and included three talented Leiden astronomers.

Open Access means shared responsibility for research programs. An interview with Prof. Huub de Groot for the Leiden Open Access Blog in the scope of the International Open Access Week.

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.

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…

The intracluster medium (ICM) is a hot, tenuous and X-ray emitting gas that pervades galaxy clusters.

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.

An Active Galactic Nucleus (AGN) is a highly luminous region at the center of a galaxy, powered by the accretion into a supermassive black hole and emitting energy from radio waves to gamma rays, often outshining the host galaxy.

A team led by Erik Danen from the Leiden Academic Centre for Drug Research has received a 3 million euros NWO Science Groot grant to unravel the first steps of metastasis. Danen will work together with biologists and theoretical and experimental physicists from Dutch Universities. ‘Understanding these…

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…

What’s the fate of our sun, when in 5 billion years from now our Milky Way will clash with the Andromeda Galaxy? Leiden astronomers have been working on calculations on this collision. They recently gave a visual sneak preview on a big tech conference.

An interdisciplinary team of researchers has won the NWO Team Science Award after conducting research regarding the authenticity of several “Hugo de Groot’s” bookchests for the Dutch TV series Historisch Bewijs. The team consisted of researchers from the University of Amsterdam, the Rijksmuseum and…

Through the clever use of two types of telescopes, a team of researchers has produced stunning images of clusters of galaxies. This not only produces beautiful images, but also provides more information about the enormous amounts of energy released around supermassive black holes in clusters. The astronomers,…

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: A. Achúcarro Co-promotor: A. Boyarsky

Catalysts are indispensable in everyday life. We know what they do and more or less how they do it, but we still lack a fundamental understanding about their functioning at an atomic scale. Therefore, Irene Groot from the Leiden Institute of Chemistry develops new measuring techniques to unravel the…

The origin and evolution of galaxies are closely tied to the cyclic feedback processes between stars and the interstellar medium (ISM).

An international team of astronomers has published the most sensitive images of the Universe ever taken at low radio frequencies, using the International Low Frequency Array (LOFAR). ‘LOFAR is unique in its ability to make high-quality images of the sky at metre-wavelengths’, said Huub Röttgering, Leiden…

Working as a diplomat for the Ministry of Foreign Affairs: for many students it would be their dream. Alumnus Tom Groot Haar is busy making it a reality. 'My career seems like a preconceived plan, but it wasn't.'

How do our cells keep DNA stored away? To find out, biochemist Remus Dame received a 3 million euro Science-Groot grant. Leiden University will share the grant with TU Delft, VU Amsterdam and the Hubrecht Institute.

Promotor: Prof.dr. S. Portegies Zwart

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.

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.

The 'Groot Nederlands Student Kampioenschap' student games have been held for the first time in two cities, Delft and The Hague. To make this happen our Campus The Hague worked together with The Hague University of Applied Sciences and Inholland University of Applied Sciences. Three students look back…

On the 19th of April, Iris van de Voorde successfully defended a doctoral thesis. The Leiden University Centre for Linguistics congratulates Iris on this achievement!

Op maandag 1 april 2024 stierf onze leermeester, vriend en gewaardeerd collega Dr. Alexander Hendrik de Groot (Sander).

The radio sky harbours both galactic and extragalactic sources of arcminute- to degree-scale emission of various physical origins. To discover extragalactic diffuse emission in the Cosmic Web beyond galaxy clusters, one must image low–surface brightness structures amidst a sea of brighter compact fore-…

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

In this thesis, we use low-frequency and high-frequency radio observations to address the following questions regarding quasars: is the radio loud/quiet quasar dichotomy real?

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.

Simulation project EAGLE has won the 2022 Group Achievement Award of the Royal Astronomical Society. EAGLE is a large collection of simulations about the formation of galaxies. The largest simulation contains as many as 6.8 billion particles and took months to calculate on the world's fastest superc…

It has now been well established that shocks and turbulent motions in the intra-cluster medium (ICM) generated through cluster mergers can produce large-scale synchrotron emission.

PhD defence

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

A full overview of BPOC/SSNMR PhD theses.

Simulations of galaxies help researchers understand astronomical observations better. The EAGLE simulation, a large project in which Leiden astronomers play a leading role, shows the evolution of the Universe, from just after the Big Bang to the present day.

HZ Kenniscentrum Zeeuwse Samenleving doet op vraag van regionale overheden en maatschappelijke organisaties onderzoek naar actuele en maatschappelijke thema’s in de provincie Zeeland. De uitkomsten van onderzoeken en analyses worden gebruikt voor kennisopbouw en als basis voor beleidsopbouw en -ontwikkeling.…

I have studied the hot, diffuse gas around and between galaxies. Specifically, I have used the EAGLE numerical simulations of galaxy formation to predict the properties of this gas, and I have used those properties to predict specific observables: soft X-ray absorption and emission lines.

A permanent exhibition on the place of humans in the cosmos. This is something Franx wants to use his Spinoza Prize for. ‘So much progress has been made that we are still trying to define the questions. In finding the answers we are constantly coming up against surprises.’