Promotor: K.H. Kuijken

A century ago, it was unclear whether the stars in the sky were clustered in groups, or widely spread in the universe.

Franx

Promotores: S.F. Portegies Zwart, E. M. Rossi

Promotores: Prof.dr. M. Franx, Prof.dr. M. Kriek (Univ. of California at Berkeley)

Promotor: Prof.dr. K.H. Kuijken, Co-Promotor: Dr. H.Hoekstra

Promotor: Prof.dr. E. F. van Dishoeck, Co-promotor: A. N. Heays

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

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.

This thesis investigates how galaxies form and what diversifies the evolutionary histories of galaxies.

Recent study led at the Leiden Observatory has observed Orion with unprecedented detail. New data from the Atacama Large Millimeter/submillimeter Array (ALMA) and other telescopes have been used to create this stunning image showing a web of filaments in the Orion Nebula. These features appear red-hot…

Rossi

This thesis aims to enhance our understanding of galaxies by testing theoretical models of galaxy formation against observations, particularly in the cases of extreme systems which have been found to have an excess of baryonic mass in their central regions, in the form of either supermassive black holes…

Twee teams of astronomers, including from the universities of Amsterdam and Leiden, have discovered how hot gas giants are surrounded by large halos of thin helium gas, an indication that they are slowly losing their atmosphere. The helium, that was recently seen for the first time by the Hubble space…

We investigate the buildup of galaxies from various vantage points. The first two chapters focus on the stellar content of galaxies, especially the distribution of stellar masses at birth and potential variations therein in various galactic environments.

Joseph Callingham from the Leiden Observatory receives the Louise Webster Prize for outstanding post-doctoral research. The prize is awarded by the Astronomical Society of Australia for Callingham’s search for the most extreme object in the Universe.

Promotores: Prof.dr. A.G.G.M. Tielens & Prof.dr. L. Kaper (UvA)

Circumstellar discs are the reservoirs of gas and dust that surround young stars and have the potential to become planetary systems.

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

Promotores: Prof.dr. J. Schaye, Prof.dr. S.D.M. White (MPA Garching)

PhD Defence

When observing star-forming galaxies, we are not only seeing stellar light, but we also see how this interacts with galactic gas and dust. This thesis contains studies of the stellar, nebular and dust properties of low mass star-forming galaxies.

OB associations are loose groups of young, massive stars. They constitute the last stage of the massive starformation process, and the context in which new stars are formed.

Galaxies form and live inside dark matter haloes. As a consequence, they are exposed to the tidal fields generated by the surrounding matter distribution: this imprints a preferential direction to the galaxy shapes, which leads to a coherent alignment on physically close galaxies, called intrinsic a…

Promotor: Prof.dr. S.F. Portegies Zwart, Co-promotor: D.C. Heggie

Promotor: F.P. Israel, Co-Promoter: R. Meijerink

Stellar feedback is a crucial ingredient in the evolution of galaxies.

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.

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.

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

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

Galaxy intrinsic alignments induce a major astrophysical contamination to weak gravitational lensing measurements and need to be modelled and mitigated when extracting cosmological information from such measurements.

When a star gets too close to a supermassive black hole, it is torn apart by strong tidal forces in a tidal disruption event (TDE).

Promotor: Prof.dr. S.F. Portegies Zwart

PhD Defence

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

Searching for ways to delay the need for a transplant and trying to build kidneys to order.

The focus of the dissertation

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.

Promotores: Prof.dr. M. Franx & Prof.dr. P.G. van Dokkum (Yale University)

At Leiden Observatory, researchers investigate the origin of stars and their planetary systems. They detect and characterize planets around other stars, which are called exo-planets. They study how stars and planets form. And they follow molecules from interstellar clouds to nascent planet systems.…

What are the 'dark' components of the universe?

To study how planetary systems come into existence we study much younger systems still in formation.

Supervisor: S.F. Portegies Zwart Co-Supervisor: A.G.A. Brown

Promotor: Jelle S. Kaastra Co-promotor: Jelle de Plaa

A remarkable population of short period transiting rocky exoplanets with equilibrium temperatures on the order of 2,000 K has recently been discovered.

Promotor: Prof.dr. V. Icke, Co-Promotor: T.I. Madura