About me
I am a researcher in astronomy at Ghent University (BE) with a strong passion for data analysis. During my PhD, I worked with large datasets mainly based on Hubble Space Telescope (HST) and James Webb Space Telescope (JWST) observations. Using typical Python libraries (Numpy, Pandas, Matplotlib, Seaborn, Scikit-learn, etc.), I created optimized codes to extract and investigate trends among the thousands of variables in these datasets. In detail, I used statistical analysis to understand the structural and morphological features of galaxies and their evolution over time. This portfolio presents some significant results (and those I am most proud of) from my work.
Publications
- A&A, 2026 – Evolution and mass-dependent variations of color gradients from UV to near-infrared with the Hubble and the James Webb Space Telescopes
- A&A, 2025 – The evolution of galaxy structure as seen by Hubble and James Webb
- ApJ, 2024 – The mass-size relation of galaxies in the near-infrared
- ApJ, 2023 – Variations in galaxy structure at different wavelengths
Scientific visualizations
Color gradients in the UVJ plane
When observing distant galaxies with powerful telescopes, the light we see reflects different processes depending on the wavelength (from near-UV to near-infrared). This plot illustrates the variation in luminosity in the near-UV (U) and near-infrared (J) bands, using optical light (V) as a reference. Most galaxies show a core dominated by infrared light, while their outer regions are bluer. The grid shows how luminosity ratios vary with stellar age and metallicity. The arrow indicates how the U–V and V–J values shift when dust is added in front of the galaxies. Such plots help us understand the dust content, star formation history, and physical components of distant galaxies.
The mass–size relation of galaxies in the infrared
The Hubble Space Telescope has accustomed us to seeing galaxies as our eyes would, but what happens when we observe them in the infrared? Do the relationships we know remain unchanged? This work shows that the mass–size relation of galaxies changes significantly in the infrared. Galaxies appear systematically smaller, and above a certain mass, their size plateaus. Additionally, this 'flattening' occurs at slightly different masses at different cosmic times (i.e., different ages of the universe).
The mass–star formation rate relation
The well-known relation between galaxy mass and star formation rate shows that the more massive a galaxy, the higher its star formation rate—unless it is quiescent, in which case the rate becomes negligible. How does galaxy structure change across this plane? This plot shows the standard deviation of the Sérsic index (n) for galaxies sharing the same mass and star formation rate (same hexbin). We find that in the optical, the scatter is high except for quiescent galaxies, while in the infrared, only a small region shows significant variation in structure.
The mass–structure relation of galaxies
This plot shows how the structure of galaxies (here, the Sérsic index n) varies with mass. Each line represents a subset of galaxies observed at different cosmic epochs, from when the universe was ~11 billion years younger to 5 billion years ago. In the infrared (left panel), there is little difference over cosmic time, but in the optical (right), galaxies observed ~5 billion years ago deviate from the others, showing a much higher index.
Codes
Contact
Contact: marco.martorano@ugent.be | GitHub | Linkedin