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

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

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.

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

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.

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

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.

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.

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.

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

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.

One of the key quests in astronomy is to study the growth and evolution of galaxies across cosmic time. Radio observations provide a powerful means of studying the formation of stars and subsequent buildup of distant galaxies, in a way that is unbiased by the presence of dust.

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

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

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.

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

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…

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

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

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

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…

Within the field of astronomy, understanding how galaxies grow and evolve from the Big Bang to the present day is a challenging and complex question.

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

Promotores: F.H. van Lunteren, F.P. Israel

Het radioprogramma Radio Weetlust besteedt elke ochtend tussen 08.00 en 09.00 uur aandacht aan het dagonderwerp van Leiden2022.

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

This thesis focuses on the study of transient and variable radio sources in the universe.

Following the Big Bang, structure in the Universe started collapsing under the force of gravity. This resulted in the formation of the first stars, galaxies and clusters of galaxies.

In this thesis we push the boundaries of high-resolution imaging at radio frequencies between 100 and 200 MHz. Using the International LOFAR Telescope that spans across Europe we achieve sub-arcsecond angular resolution.

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

The Low Frequency Array enables studies of low-frequency carbon radio recombination lines with unprecedented sensitivity, spectral and spatial resolution.

In this thesis new methodologies are developed for the detection and systematic study of radio sources in the early universe. This allows us to gain a deeper understanding of the formation and evolution of galaxies, the activity of supermassive black holes, and the final phase transition of our universe:…

Een podcast waarin wij geleerden, auteurs en kenners uit uiteenlopende vakgebieden uitgebreid interviewen over hun onderzoek en/of nieuwe publicaties. Iedere drie weken verschijnt hier een nieuwe aflevering van een uur tot anderhalf uur. Zo kunt u vanuit het comfort van uw eigen huis plaatsnemen in…

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

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.

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?

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

On the largest scale, the Universe resembles a cosmic spiderweb. Most galaxies coexist in small groups within the threads of this web. At the nodes of the threads are enormous groups of galaxies forming the largest structures in the universe still held together by gravity: clusters of galaxies.

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.

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.

Pulsars were first discovered in 1967 and since then the population has grown and expanded over several wavelengths.

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-…

Understanding how galaxies form, interact, and evolve comes largely from comparing theory predictions with observational data. Numerical simulations of galaxies provide the most accurate approach to testing the theory, as they follow the non-linear evolution of gas and dark matter in great detail and…