Tim van der Vuurst

Since 2019, I have been studying Astronomy at Leiden University. I completed my bachelor in 2022 and will finish my master with the Data Science specialization in the summer 2026.
Throughout my studies, I have found to particularly enjoy working with astrophysical modeling, numerical simulations and the data science parts of astronomy. In the many fields of astrophysics, I have mostly been drawn to astronomical transient events, galaxy formation and large scale structure, though I am deeply interested in all of astronomy and will enjoy working on any topic through the lens of a data scientist and programmer.
Currently, I am working on my second master's thesis under Dr. Marcel van Daalen which focuses on modeling redshift-space distortion (RSD) effects using the FLAMINGO simulations. I am using the unprecendented scale and accuracy of FLAMINGO to model the peculiar velocities of galaxies in a two-pronged approach: modeling the 'one-halo' contribution (intra-halo movements) and the 'two-halo' contribution (inter-halo movements).
Furthermore, I am co-authoring a paper with Lucas Pouw, Yannick Badoux and Prof. Dr. Simon Portegies Zwart on the von Zeipel-Lidov-Kozai driven mass loss of the circumbinary disk around S-cluster stellar binary D9.
When I am not busy with research, I enjoy making music with my band, playing sports (mostly weight lifting and bouldering), video games and spending time with friends. In the past, I have also been an actor and subsequently director and writer for my association's amateur theater group "De Revue".
I have worked as a teaching assistant for various courses at Leiden University over the course of my studies and still do so with much enjoyment. I've helped for the courses Practical Astronomy (4 years), Programming Methods for Physics (2 years), Machine Learning (1 year) and two brand-new courses for the Physics Minor which I could help shape: "Einstein's Universe - relativity and black holes" and "Cosmology - where do we come from?".

My full CV is available here.

Current research and publications

I am currently working on two seperate research projects, one of which is in preparation for publication. If you want to know more, feel free to contact me.

Modeling RSD effects in FLAMINGO

Master Research Project under Dr. Marcel van Daalen

Redshift-Space Distortions (RSDs), such as the Finger of God and the Kaiser effects give a warped view of galactic distances, since we do not accurately know the non-Hubble (i.e. peculiar) velocities of distant galaxies. In my current project, I am focussing on using the FLAMINGO simulations to create a statistically sound model to describe these peculiar velocities and model the subsequent RSDs. For this, I am modeling both a "one-halo" term and a "two-halo" term, which is to say the intra-halo motions and inter-halo motions respectively. My work builds directly on the master thesis by Sowmya Parthasarathy.
Shown on the left is a figure containing histograms for the velocities of all halo pairs at different radial seperation bins. The halo pair velocities are projected to the line connecting them and are defined to be negative when the haloes move toward each other. The halo pairs, consisting of a primary and secondary, are further selected by having a mass in the range 10^12.5-13 M_Sun for the primary halo and 10^13-13.5 M_Sun for the secondary. Of particular interest is the non-Gaussian skew and kurtosis at low distance, showing the effect of the gravitional pull these haloes have on each other. The aim of the project is to eventually find a non-binned functional form (i.e. explicit mass and radius dependence) for both this two-halo result and the one-halo velocity distribution.

Kozai driven mass loss of the circumbinary disk around S-cluster stellar binary D9

Paper in preparation with Yannick Badoux, Lucas Pouw and Prof. Dr. Simon Portegies Zwart

What started as a small project for the course "Simulations and Modeling in Astrophysics" has turned into a paper nearly ready for publication a little under a year later, under the guidance of Prof. Dr. Simon Portegies Zwart. Motivated by the discovery of a stellar binary with a possible circumbinary disk in the S-cluster ( Peißker et al. 2024), we created gravito-hydrodynamical simulations of the D9 system using AMUSE. We found von-Zeipel-Lidov-Kozai (vZLK) driven mass loss in the circumbinary disk that is periodic with the vZLK timescale. On the left, you can see a video showing the first ~80kyr of the system and can see the vZLK precession of the disk.
This work is currently in preparation and will be sent to a referee soon. All authors contributed equally to this work.

Previous reserach

In the past, I have done two research projects: one for my bachelor's and my first master project. If you want to know more, feel free to contact me.

A photometric population study on nuclear transient events from the Zwicky Transient Facility

First Master Research Project supervised by Dr. Sjoert van Velzen.

The Zwicky Transient Facility (ZTF) measures the light curves in various photometric bands of many astronomical transients. Motivated by wanting a better method to identify these transients that do not require spectroscopic follow-ups, I created a method to fit a Gaussian rise and exponential decay model to all these light curves. Then, we can create a dataset of all these parameters beloning to the lightcurves and possibly find a distinct difference between the transient types. One such phase space slice can be seen on the left, plotting the (logarithm of) the decay time against the (logarithm of) the rise time as an example. Clearly, there is some preference between the transient types. For clarity: AGN refers to Active Galactic Nuclei, SN to Supernovae and TDE to Tidal Disruption Events. My research served as the foundation of subsequent research by Britt Ottevanger, who managed to create a machine learning model that is fairly accurate at discerning the different transient events based only on the photometric measurements.
My thesis can be read here.

The supermassive black hole - host galaxy mass scaling relation in FLAMINGO.

Bachelor Research Project supervised by Prof. Dr. Joop Schaye and Zorry Belcheva, MSc

Using FLAMINGO, Owen Hagedooren and I investigated the supermassive black hole - host galaxy mass scaling relation, which can be seen summarized in the plot to the left. Our project served as preliminary research and yielded an acknowledgement in the official FLAMINGO release.

Skills

• Python, Unix, LaTeX and Github proficiency.
• Bayesian methods, numerical simulations and statistical modeling.
• High-energy transients, Galaxy formation, large scale structure, Galactic Center kinematics,
• Dutch (native), English (C2), German (B1)
• Academic research, writing and presenting; university-level teaching

Contact Me

You can contact me at vdvuurst@strw.leidenuniv.nl.
You can also find me on LinkedIn.