Large areas of space are filled by molecular clouds that consist of gas and dust grains that are the remnants of dead stars. When these clouds start collapsing, the decreasing temperature and increasing density cause gas particles to start accreting onto dust grain surfaces.

Promotor: Prof.dr. I.A.G. Snellen, C.U. Keller

Multiple stars, that is two or more stars composing a gravitationally bound system, are common in the universe.

More than 5,000 exoplanets have been found over the past couple of decades. These exoplanets show a tremendous diversity, ranging from scorching hot Jupiters, common super-Earths, to widely separated super-Jupiters on the planet/brown dwarf boundary.

This thesis focusses on the temperature structure in protoplanetary disks. The relation between structures seen in the dust and gas-phase molecules is investigated.

Hot astrophysical plasma is ubiquitous in the Universe, from comets in our Solar system to the largest scale structures -- the cosmic web filaments. These hot plasmas, with the temperature of a few millions of degrees, are often observed in the X-ray wavelength range.

Promotor: E. F. van Dishoeck, Co-promotor: C. Walsh

Over the last three decades, the discovery of exoplanets has revealed the boundless variety of worlds beyond our own Solar System⁠. Majority of planetary systems contain short-period planets that are larger than Earth but smaller than Neptune⁠.

Promotor: Prof.dr. E.F. van Dishoeck

A dense region of a gaseous and dusty cloud collapses to form a protostar surrounded by a disk and an envelope. This thesis uses both observations and models to study physical and chemical conditions of these protostellar systems which are likely where planets start to form.

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

The physical origin of the dozens of stellar-mass binaries, the mergers of which have been detected by the LIGO-Virgo-KAGRA collaboration via gravitational waves, is still unknown.

Nowadays, it is well known that hydrogen and helium (and small traces of lithium and beryllium) were created shortly after the Big Bang, while the heavier elements are created in the cores of stars at different evolutionary stages. When these stars explode as supernovae, they expel metals synthesised…

Until the 1990s, the only known planets were those in our Solar System. Three decades later, several thousand exoplanets have been discovered orbiting stars other than the Sun, and substantial efforts have been made to explore these strange new worlds through spectroscopic analyses of their atmosphe…

The focus of this thesis is how stars like our Sun and planets like Jupiter, Saturn, and Earth are formed.

Promotor: J.S. Kaastra Co-promotor: E. Constantini

Promotor: I. A. G. Snellen, Co-promotor: M. A. Kenworthy

Promotie

Lezing, LACG Meetings

Lezing, LIMS seminar

Simon Portegies Zwart, hoogleraar Computationele Sterrenkunde, gebruikt de rekenkracht van computers om de evolutie van sterren te simuleren. We praten met hem over zijn vakgebied en over de uitdagingen van het werken met enorme hoeveelheden complexe data.

De Nederlandse Onderzoekschool voor Astronomie krijgt twee nieuwe directieleden. Ronald Stark (nu nog werkzaam bij NWO) is per 1 september de nieuwe uitvoerend directeur van NOVA. Amina Helmi (hoogleraar Dynamica, structuur en vorming van de Melkweg aan het Kapteyn Instituut van de Rijksuniversiteit…

Na jaren van ontwikkeling is het moment eindelijk daar: een enorme cryostaat, een bijzonder geavanceerde vriezer die de gevoelige onderdelen extreem koud houdt, is vanuit Zürich in Leiden aangekomen. Het apparaat is het grootste onderdeel van METIS, een van de eerste instrumenten op ESO’s Extremely…

De zoektocht naar leven elders in het heelal is weer een stapje verder, dankzij de Leidse astrofysicus Matteo Brogi. In zijn proefschrift, waarop hij cum laude promoveerde, demonstreert hij een nieuwe methode om verre planeten te onderzoeken.

Na 30 dagen hard werken is de experimentele replica van de ijzertijdkano van Vlaardingen Vergulde Hand klaar! Vlaardingse schoolkinderen zullen de kano op 16 februari te water laten.

Promotor: Prof.dr. G.J. Kroes

In this thesis, we used genetically engineered mouse models to identify genes and pathways that are involved in ILC formation and in the development of resistance to FGFR-targeted therapy.

Hoe verwerken we taal en spraak? Hoe voegen we de informatie op verschillende niveaus – intonatie, zinsstructuur, betekenis, toon, woorden, klanken - samen? Hoe staat de informatie op het ene niveau in verband met informatie op een ander niveau?

In the last decades, activity-based protein profiling (ABPP) has emerged as a powerful chemical tool that may aid the ever-challenging drug discovery process.

A single self-assembled semiconductor quantum dot in a high-finesse optical microcavity - the subject of this thesis - is an interesting quantum-mechanical system for future quantum applications. For instance, this system allows trapping of an extra electron and thus can serve as a spin quantum memory,…

The glycosylation reaction is a pivotal reaction in creating new and complex oligosaccharides.

Welke rol spelen stress en angst bij de vorming van nocebo hyperalgesie?

To improve cancer treatments, personalized medicine approaches have aimed to identify exactly which mutations are driving tumor development in a given patient and specifically target these mutations using precision therapies.

This thesis systematically studies the physicochemical properties of non-planar, propeller-shaped, polycyclic aromatic hydrocarbons. The synthesis of several so-called propellerenes is described on a gram scale, using optimized procedures aimed at using less hazardous reagents and reducing the amount…

In order to be able to develop effective medicine and treatments to prevent or cure autoimmune diseases or cancer we need to understand the mechanisms how they arise and what drives their course.Unravelling the fundamental molecular mechanisms influencing the onset and course of diseases such as allergies,…

In this thesis, mathematical modeling and simulation was applied as a tool to inform quantitative decision making in oncology drug discovery and development.

A difficulty of studies on chemical kinetics are the reaction time scales and detection of their intermediates.

This thesis surveys the intersection of computed tomography (CT) and machine learning (ML), treating CT as an ill-posed inverse problem shaped by object properties, imaging physics, and data limitations.

Promotor: Prof.dr. M. Danhof, Co-promotor: O.E. Della Pasqua

A P300-based Brain Computer Interface character speller, also known as P300 speller, has been an important communication pathway, under extensive research, for people who lose motor ability, such as patients with Amyotrophic Lateral Sclerosis or spinal-cord injury because a P300 speller allows human-beings…

Lezing

Het is de grootste database voor ruimte-ijs ooit: De Leiden Ice Database for Astrochemistry: LIDA. LIDA is gemaakt door astrofysici van de Leidse Sterrewacht en omvat niet alleen honderden meetgegevens, maar ook programma’s om astronomische waarnemingen te onderzoeken en nieuwe metingen met de James…

Detecting planets during their formation stages is crucial for understanding the history and diversity of fully developed planetary systems like our own. However, observing young planets directly is challenging because they are often deeply embedded within their host protoplanetary discs, rich in gas…

Diverse types of exoplanets such as gas giants on close-in orbits (hot Jupiters) and young massive giants on wide orbits (super Jupiters), with no analogs in the Solar System, pose challenges but also opportunities to our understanding of planet formation and evolution.