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…

Outflows are crucially important for the gas budget and evolution of luminous star-forming galaxies and AGNs, with observed mass outflow rates of the same order as the star formation rate. Greater star formation and black hole growth lead to more intense feedback and outflows, resulting in self-regulated…

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.

The work presented in this thesis is based on ALMA surveys of protoplanetary disks in three star-forming regions: Lupus, OMC-2, and NGC 2024.

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

Stars like the sun are born in large molecular clouds existing from gas and dust. During the formation process, the chemical composition of the material can be altered drastically by the changing physical conditions.

Understanding the formation and evolution of planetary systems is one of the most fundamental challenges in astronomy. To directly image and study young exoplanets and the circumstellar disks they form from, dedicated high-contrast imaging instruments are built.

This thesis examines the link between simple molecules and the underlying structure and chemistry within protoplanetary disks - the birthplaces of planets.

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

Promotores: Prof.dr. E.F. van Dishoeck, Prof.dr. C.P. Dullemond

This thesis discusses the physical and chemical processes than influence the composition of forming planets.

Complex Organic Molecules (COMs) have been detected in objects across different stages of stellar evolution.

Low-mass main-sequence stars like our Sun are continuous sources of outflowing hot magnetised plasma. In the case of the Sun, this is known as the solar wind, whereas for other stars they are called stellar winds.

This research focuses on the distribution of chemical elements in protoplanetary disks, the birthplaces of planets. These disks form around young stars and contain gas and dust, from which planets grow. Ice plays a crucial role in planet formation, aiding the clumping of dust particles and influencing…

This dissertation is an experimental study of laser-generated, atmospheric pressure, transient toroidal helium plasmas.

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

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

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.

My work is motivated by the necessity to extend Standard Model of Particle Physics in order to explain three observed phenomena that this great theory fails to accommodate

One of the key discoveries in exoplanet research over the past decade is the abundance of small planets in our Milky Way. Despite their high numbers, our understanding of their atmospheres remains limited, and it is unknown if they possess atmospheres at all.

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…

A large diversity of exoplanetary systems has been found, but it is still unclear what drives this diversity.

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.

This thesis addresses the chemical processes that determine the compositions of giant planet atmospheres.

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

My work focuses on a class of astronomical objects called protoplanetary disks.

This thesis focuses on the X-ray spectral analysis of merging galaxy clusters and the plasma code development for future high-resolution X-ray spectroscopy observations.

To address the fundamental questions of how life on Earth emerged and how common life may be in the Universe, it is crucial to know the chemical composition of the planet-forming material.

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

Promotor: Prof.dr. E.F. van Dishoeck, Co-Promotor: M.R. Hogerheijde

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

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.

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.

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.

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

Promotor: Prof.dr. E.F. van Dishoeck, Co-promotor: S. Bruderer

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

The ultimate goal of cosmologists is to find a cosmological model able to explain the current observational data.

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

This thesis describes the Multi-site All-Sky CAmeRA (MASCARA), which consists of two small robotic telescope designed to detect exoplanets around the brightest stars in the sky.

Polycyclic aromatic hydrocarbons (PAHs) are the most abundant class of organic compounds in space. The PAH field evolves from the constant interaction between experimentalists, theorists, modellers and observers. While laboratory research and quantum chemical calculations together set up the molecular…

With his clever measuring methods Ignas Snellen – together with his team – was the first to detect carbon monoxide in the atmosphere of exoplanets. For his pioneering work the Leiden astrophysicist has been awarded the Spinoza Prize, the highest academic honour in the Netherlands. The prize of 2.5 million…