My Work
My studies allow me to combine my hobbies, like programming, with abstract complex concepts such as the origins and evolution of the Universe. Hereby, I like to work with and develop new funky techniques that can give new insights into my fields of interest, which range from observational cosmology to high-resolution observations of the centers of galaxies.
Some of these funky techniques are:
A bayesian-forward-modelling routine that works in the native plain of interferometric observations,
A new Bayesian deconvolution algorithm that favours the recovering of large spatial scales.
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 from cosmological hydrodynamical simulations.
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.
ReCESS,
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, morphology, and evolution as I have explained in this talk.
Characterizing the pressure distribution is important for cluster cosmology but also for galaxy evolution studies. For instance, through SZ measurements combined with spectral lines -- which are co-detected with ALMA --, we can link the role the environment has on cluster members in this seminal epoch of the Universe.
Papers:
Local Cool-Cores,
Cool cores are galaxy clusters for which the X-ray emission strongly peaks in the center. This would suggest that the core of this type of cluster of galaxies cools rapidly through radiative cooling and hence their name. However, characterizing the inner regions is not as straightforward as one might think.
Through multi-wavelength observations (radio, molecular lines, SZ-effect, optical, and X-ray), we try to get a complete view of all the mechanics at play in the inner regions of cool cores. 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.
Papers:
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)
We observe sloshing (major drift motion of the ICM) around the cool-core cluster RXC J2014.8.
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!
A_Needle_in_a_Haystack.pdfMy work is continued in a series of 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.
Papers:
PRUSSIC II -- ALMA imaging of dense-gas tracers in SDP.81: Evidence for low mechanical heating and a sub-solar metallicity in a z=3.04 dusty galaxy (M. Rybak, J. van Marrewijk et al. 2023)
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 by what JWST will bring in terms of detections and the characterization of galaxies around the epoch of reionization. Luckily, we can already have a sneak peek with ALMA as done in this paper. But ALMA data is not always as intuitive as one might think...
Papers:
ALMA as z>10 line finder (J. van Marrewijk, M. Kaasinen et al. in Prep.)
To see or Not to see a z~13 galaxy? That is the Question (M. Kaasinen, J. van Marrewijk, G. Popping et al. 2023)
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's 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 creates 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!
Precision_Cosmolgy_with_Galaxy_Clusters.pdfRequesting Observation Time
As an observer, a large part of my job is writing proposals. I try to provide compelling science cases so that my targets are observed by world-leading facilities such as ALMA and the Green Bank Telescope. Hence, over the last two years, I have developed and led (as PI) over seven proposals and contributed to at least 20 others as co-investigator. For example, I contributed to a 2021 ALMA Directors Discretionary Time proposal targeting the proposed youngest-ever galaxy. Furthermore, I was the main PI of an ALMA Large program leading the ACT collaboration to propose a ~400-hour ALMA+ACA endeavour, showing my drive to explore new scientific ideas and that I am not afraid to take on large projects
The Green Bank Telescope, located at Arizona, USA.