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.

Since it was announced that North Korean President Kim Jong-un is ready to launch an intercontinental nuclear missile, fear of a nuclear war is growing by the day. Professor and North Korea expert Remco Breuker talks about the increased international tensions and their consequences for his work.

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.

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.

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.

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.

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,…

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

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…

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 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

Trust and reciprocity are two important social behaviors that help adolescents to navigate their social world successfully. In their empirical article in Journal of Research on Adolescence, van de Groep, Meuwese, Zanolie, Güroğlu, and Crone describe the development of trust and reciprocity in adolescents…

A study on the development of prosocial behaviour.

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.

Promotor: Prof.dr. E.F. Smets, Co-promotor: Dr. V.S.F.T. Merckx

Wat zijn de huidige energiekosten en hoe is de comfortbeleving het wooncomfort in een bepaalde groep huurders van woningcorporatie Portaal?

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

PhD defence

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.

De onstuitbare opmars van de N.V. Zuid-Korea. (in Dutch).

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.’

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.

Promotor: Prof.dr. A.G.G.M. Tielens, Co-Promotor: J.B.R. Oonk

Rottgering

Inaugural lecture

During the Leiden Science Family Day, you can take part in various workshops. You can also watch various demonstrations. Where will you go?

Large telescopes can look so deep into the Universe that they can also look back billions of years in time. From 2018, the successor of the Hubble Space Telescope, the James Webb Space Telescope, will be able to see the period just after the Big Bang, when the first stars and galaxies formed. Astronomers…

These are the proposed research projects for LEAPS 2019. Please note that not all projects will go ahead and some may still be added in the near future. Final funding decisions lie with the Faculty sponsors. And please make a note that if you are interested in an ESA project, to check if your state…

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.

Overview of the Leiden Asia staff per area or country.

PhD defence

Promotor: Prof. dr. A.G.G.M. Tielens

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

Research at Leiden Observatory spans the full width of modern astrophysical enquiry. It is based on observation, theory, simulation, and experiment. Two broad clusters characterize the ongoing research. Within each theme, researchers carry out their personal and specialized research programme. The two…