Student Projects

Would you like to do your BSc or MSc project within our (objectively awesome) collaboration at Leiden Observatory and TU Delft? Please get in touch, ideally by e-mail. 

Currently offered projects

Deciphering thermodynamics of star formation in early galaxies

As revealed by ALMA and JWST, galaxies in the early Universe formed stars at rates far higher than we see today. What fueled this intense activity? The key lies in their dense gas— traced by, e.g., HCN, HCO+, HNC). Thanks to powerful telescopes like NOEMA and ALMA, detections of these tracers in distant galaxies have surged. But to get a proper understanding what’s going on in these galaxies, we need to understand the actual physical conditions of their star-forming gas (temperature, density, turbulence).

We will tackle this critical gap by analysing extensive NOEMA and ALMA observations of HCN/HCO+/HNC emission in a sample of ~10 lensed galaxies. The student will use cutting-edge tools for radiative transfer modelling (e.g., RADEX), coupled with astrochemical networks (e.g., UCLChem) to determine density, temperature, and molecular abundances in targeted galaxies. This is a highly novel project: the first time such analysis will be performed for high-redshift galaxies.

Cyanide in space – looking for dense-gas tracers in early galaxies

Galaxies in the early Universe were forming stars rates 100-1000x higher than present-day ones. What was driving their immense star-formation rates? While our current facilities have mapped stars (JWST) and (mostly) diffuse gas (ALMA), we have been missing the critical link – the dense gas from which stars actually form. This dense gas is traced by fainter emission lines of HCN - cyanide, HCO+, and HNC. However, the number of dense-gas detections (particularly the low-excitation lines) beyond redshift z~0.2 remains very limited. In this project, we will use deep VLA observations of HCN, HCO+, and HNC lines from the PRUSSIC programme. These are the most sensitive observations of dense gas in early galaxies ever taken. Specifically, we will compare the intensity of these lines in sources dominated by star formation vs sources dominated by active galactic nuclei. The project is ideal for a student looking for a hands-on experience with radio data.

Exampled of previous projects

What will AtLAST see? Simulating spectroscopic observations for the future mm-wave surveys

Student: J. Hillhorst

Supervisors:  M. Rybak, A. Endo, J. Hodge

One of the main challenges for high-redshift astrophysics is to map the 3D distribution of galaxies to the Epoch of Reionization and beyond. As most high-z, massive star-forming galaxies are hidden beyond thick dust shrouds, pin-pointing their spatial positions and redshifts requires observations at sub-mm wavelengths. Unfortunately, large (sub)mm redshift surveys have long remained very time-consuming due to the limited bandwidth of most heterodyne receivers.

The rapid progress in THz technology - particularly the advent of kinetic inductance detectors - now puts ultra-wideband, many-pixel (sub)mm spectroscopy within reach. As a result, several new instruments and telescopes are planned to launch in the late 2020s, culminating in a 50-m AtLAST telescope in the 2030s. The key science objective of these instruments will be blind redshift searches for high-z galaxies emitting the [CII] 158-um or [OIII] 88-um lines. But what will these surveys actually see?

In this project, we will use mock observations of line emission ([CII], [OIII], CO...) from high-redshift galaxies to determine:

- How many high-z [CII]/[OIII] emitters will we detect?

- What is the best observing strategy?

- How likely are we to confuse a low-z CO line with a high-z [CII]/[OIII]?

Specifically, we will first use existing large-volume simulations and analytical prescriptions for calculating line emission from a realistic 3D distribution of galaxies. In the second step, we will create mock wideband observations with current and planned instruments - particularly the future upgrade of DESHIMA and MOSAIC spectrometers under development at TU Delft and SRON.

Here are some areas in which student projects are possible:

• Gravitational lens analysis: Many gravitational lenses are lacking high-precision models which are necessary for reconstructing high-resolution data. They allow us to study the sources at super high resolution! Past examples:

Brigitte Pruit (MSc): Gravitational Lens Modelling of z ∼ 2-4 dusty star forming galaxies and the CO(9-8) vs FIR relation

• Observations of high-redshift galaxies (mostly with ALMA and VLA). Past examples:

Bryndis Ragnarsdóttir (MSc): Dust Continuum Morphology of High-Resolution ALMA Submillimeter Galaxies: uv-Plane versus Image-Plane Modeling

G. Jolink (BSc): A VLA search for dense molecular gas in high-redshift galaxies

• Investigating simulated galaxies: We are working with EAGLE and SIMBA teams on using resolved galaxies in cosmological simulations to both understand the observations, and drive better simulations. Past examples:

T. Stockmans (MSc): Investigating the [CII]/FIR-deficit in high-resolution simulations

A. van Ogtrop (BSc):  Studying high-redshift galaxies with ALMA: biases due to complex source structure and companion sources 

• Developing and applying advanced data analysis techniques for ALMA/VLA data.

J. van Marrewijk (MSc): Detecting dense gas tracers in gravitationally lensed galaxies through a matched filter in the uv-plane

Leiden Observatory website provides more details on BSc (2019 version) and MSc projects.