This research delves into a region of space known as the interstellar medium (ISM), which is essentially the area between the stars filled with gas and dust.

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.

Galaxies in the local Universe fall into two main categories of spirals and ellipticals. In this Thesis, we explore the structural evolution of galaxies into this bimodal distribution.

Radio jets are important to the evoultion of galaxies. However, it is still not fully understood how a radio jet can be triggered.

This thesis explores the theoretical and observational properties of distant massive galaxies that harbour active black holes in their centres and shine brightly at radio wavelengths.

The thesis deals with the study of giant radio galaxies (GRGs), which are radio galaxies of megaparsec sizes.

The formation and evolution of galaxies is fundamentally driven by the formation of new stars out of cold gas.

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.

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

Promotor: M. Franx, Co-Promotor: I.F. Labbé

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…

This thesis investigates the structural evolution and assembly of galaxies since the first few billions years after the big bang.

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…

Galaxies are environments where gas coalesces, cools, and is converted into stars. However, it remains unclear the exact mechanisms through which galaxies acquire, redistribute and lose their gas.

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.

Promotor: H.J.A. Röttgering, Co-promotor: M. Haverkorn

Promotor: H.J.A. Röttgering, Co-promotor: G.K. Miley

The origin and evolution of galaxies are closely linked to many different physical phenomena.

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

Promotores: Prof.dr. J. Schaye & Prof.dr. C. Steidel (California Institute of Technology)

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

Promotor: Prof.dr. H.W. Lenstra

Promotor: Prof.dr. M. Franx, Co-Promotor: Rychard Bouwens

The unit residue group, to which the present thesis is devoted, is defined using the norm-residue symbol, which Hilbert introduced into algebraic number theory in 1897.

Wetenschappers bij de Leidse Sterrewacht onderzoeken de fundamenteel natuurkundige verschijnselen die voor structuur in het heelal zorgen. Deze processen brengen materie bijeen tot sterrenstelsels en gas bijeen tot sterren. Met behulp van krachtige telescopen en geavanceerde berekeningen en computersimulaties…

Promotor: Prof.dr. P. Stevenhagen

Promotores: H.W. Lenstra, A. Lucchini

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

Promotor: S.M. Verduyn Lunel, Co-promotores: M.F.E. de Jeu, B. de Pagter

In my research, we developed a method to distinguish knots. A knot is a mathematical depiction of the everyday knot that occurs in ropes and cords.

The extensive use of electronic communication channels and other devices has opened new possibilities for collecting data on human behavior. This information is sometimes openly accessible, but largely part of administrative registration systems that are not open to the broader public. The data provides…

The main topic of this PhD thesis is the Arakelov ray class group of a number field, an algebraic object that contains both the ideal class group structure and the unit group structure.

Promotor: E. Gittenberger, Co-promotores: B.W. Hoeksema; L.P. van Ofwegen

This dissertation is a collection of four research articles devoted to the study of Kummer theory for commutative algebraic groups.

Promotores: Prof.dr. F.P. Israel, Prof.dr. P.P. van der Werf

Terroristische groepen passen zich aan veranderingen in hun omgeving aan om relevant te blijven. Dit project biedt nieuwe inzichten door een theorie over strategische doelwitselectie te ontwikkelen en big data-analyse en machine learning toe te passen om de hypothesen te testen.

Promotor: Prof.dr. P. Stevenhagen, Prof.dr. K. Belabas (Univ. de Bordeaux)

Promotores: P. Stevenhagen, E. Fouvry (Univeriste Paris Saclay)

Dark matter is one of the biggest mysteries of the Universe. Its properties cannot be explained with the known laws of physics and elementary particles.

The thesis focuses on synthesis strategies in oligosaccharide campaigns, and the influence of protecting groups.

Freshwater and brackish water ecosystems are arguably the most vulnerable ecosystems on earth, due to concentrated human developments in and around them. The Pontocaspian (PC) region located at the border of Europe and Asia contains a variety of brackish water ecosystems and unique inhabitants, known…

Whilst government’s ability to design ‘context-specific’ regional innovation policy is generally assumed to depend on the region’s decision-making power, the aim of this study is to investigate how regional government matters. In order to open up the black box of policy design, the study develops a…

Promotor: Prof.dr. W.T.F. den Hollander

Let A be a commutative algebraic group over a field K, and let G be a finitely generated subgroup of the K-rational points of A. The purpose of this thesis is to study the degrees of the Kummer extensions relative to A,K and G.

Most of current public-key cryptography is considered insecure against attacks from sufficiently powerful quantum computers. Post-quantum cryptography studies methods to secure information resistant against such attacks. One proposal is isogeny-based cryptography, which bases its security on computational…

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.

In this thesis we classify the pairs (p,G), where p is a prime number and G is a finite p-group possessing an intense automorphism, i.e. an automorphism that sends each subgroup of G to a G-conjugate, that is non-trivial and whose order is coprime to p.

Promotor: H.J.A. Rottgering, Co-Promotor: R.J. van Weeren

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

We explored how to morphologically classify well-resolved jetted radio-loud active galactic nuclei (RLAGN) in the LOw Frequency Array (LOFAR) Two-metre Sky Survey (LoTSS) using machine learning.