Matthee Group

Astrophysics of Galaxies

Galaxies such as our own Milky Way are the largest bound structures in our Universe and consist of gas, stars, planets, black holes and dark matter. The astrophysical processes that occur in galaxies happened to every atom in our body and therefore teach us about our own cosmic origins. The Matthee group investigates the physical mechanisms that determine how galaxies and their constituents form and evolve using observations of the very distant Universe.

Galaxies form following the collapse of small perturbations in the initial density distribution that formed in the Big Bang. While the physics of gravitational collapse is well understood, detailed feedback processes that happen within galaxies, such as the formation of stars, supernova explosions and the growth of supermassive black holes are poorly understood, while they have significant impact on the fate of galaxies and the stars and planets within them. The Matthee group uses observations of galaxies in the distant Universe to look back in time and probe the properties of the young massive stars in these galaxies responsible for the creation of the majority of heavy elements and the production of most of the ionizing radiation in the early Universe, and their impact on interstellar gas clouds. Matthee uses the largest telescopes on Earth (such as ESO’s Very Large Telescope in Chile) and in space (such as NASA/ESA/CSA’s James Webb Space Telescope) to find and study the first generations of galaxies and focus on empirically mapping the interplay between these galaxies and intergalactic gas in the so called reionization epoch that was the last major phase transition of matter in the Universe and happened only a few hundred million years after the Big Bang. Matthee also uses large cosmological hydrodynamical simulations to investigate the relation between structure formation, galaxies’ growth rates and their imprints on chemical enrichment.