My Work

My studies allow me to combine my broad astronomical interests, ranging from observational cosmology to high-resolution observations of the centres of galaxies. To study these topics, I like to work with and develop new funky techniques that can give new insights into the data. These techniques range from:

  • A bayesian-forward-modelling routine that works in the native plain of interferometric observations,

  • A matched filter with a high spatial and spectral resolution, applied in the uv-plane to detect weak spectral lines in distant galaxies,

  • A semi-analytical toy model that creates mock observations of galaxy clusters.

Below you can find an overview of all the work I am involved in.

A high spatial resolution view of the hot gas in the ICM. In blue, we show how ALMA can resolve the inner regions of the ACT (yellow) detected galaxy cluster.


The Representative Cluster Evolution SZ Survey (ReCESS) is a project that resolves the intracluster medium (ICM) in galaxy clusters at high redshifts, z>1, via the Sunyaev-Zel'dovich (SZ) effect. Resolving high-z galaxy clusters that are previously observed with survey telescopes such as ACT and SPT gives insight into their dynamical state and morphology. Combined with spectral lines -- which are co-detected with ALMA -- and optical/NIR observations, we can link the role the environment, particularly the ICM, has on cluster members in this seminal epoch of the Universe.

Local Cool-Cores,

Cool cores are galaxy clusters for which the temperature in the centre of the cluster rapidly drops. This creates a strongly peaked profile in the X-ray, as the X-ray emission is proportional to the density squared. Through multi-wavelength observations (radio, molecular lines, SZ-effect, optical, and X-ray), we characterize the inner regions of cool cores to get a total view of their dynamics. This will give insights into the coupling between processes such as cooling flows, sloshing, and AGN feedback from the smallest to the largest scales.

Check, for instance, this talk I gave about RXC-J2014.8, the strongest cool-core in REXCESS.

  1. The strongest cool core in REXCESS: Missing X-ray cavities in RXC J2014.8-2430 (T. Mroczkowski, M. Donahae, J. van Marrewijk et al. 2022)

Prussic acids at z>2,

What drives star formation in starburst galaxies around the cosmic noon? That is the question I tried to answer in one of my master's theses. In this master thesis (supervised by J. Hodge and M. Rybak), I developed an advanced data analysis technique that searches for weak spectral lines in distant galaxies through a matched filter in the uv-plane. Here, I detected the first HCO+(4-3) line in a high redshift SMG. This detection was visible in the image plane with a resolution of 20 mas!


My work is continued in a series of future papers that will characterize how dense gases are manifested in multiple starburst galaxies around the cosmic noon. This will help us understand what fuels star formation in these extreme galaxies.

  1. Prussic I -- a JVLA survey of HCN/HCO+/HNC(1-0) emission in z~3 dusty galaxies: Low dense-gas fractions in high-redshift star-forming galaxies. (M. Rybak et al. 2022)

Beyond the epoch of Reionization,

I am intrigued with what the JWST will bring is in terms of detections and characterisation of galaxies around the epoch of reionization. Luckely, we can already have a sneak peek with ALMA such as done in this paper. But, there is more to come. I can't tell you much now but stay tuned as more will follow!

Figure from: Harikane+2022

Toy Modeling Galaxy Clusters,

To enable precision cosmology with future survey telescopes, the community needs to understand the intrinsic scatter in the objects they observe. In my master thesis (supervised by H. Hoekstra and S. Debackere), I looked at how small-scale clumping in the ICM affects the X-ray luminosity - halo mass relationship. To study systematics, I created a phenomenological model, which was based on hydrodynamical simulations, that created mock observations of galaxy clusters in the X-ray for varying clumping properties. If you want to know the results, just check out the thesis, which is attached below!