Thesis Topic: Probing the Baryon Cycle


Thesis Supervisors: Celine Peroux and Harald Kuntschner


The physical processes by which the gas is accreted onto galaxies, tranformed into stars and then expelled from galaxies are of paramount importance to galaxy evolution studies. Observationally constraining each of these baryon components in the same systems is however extremely challenging. Absorption lines detected against background quasars offer the most compelling way to study the cold gas in the circumgalactic medium (CGM).

The project will use a dataset from a recently awarded Hubble Space Telescope (HST) Medium Program. The unique sample comprises 17 VLT/MUSE quasar fields, comprising 40 z<0.85 absorbers and 120 associated galaxies, some of which are also detected in CO with ALMA as well as an additional sample of 200 z<1.2 galaxies with MgII coverage from quasar spectroscopy. These remarkable observations will provide a measure of their stellar mass, dust content, age of their stellar population, constrain their resolved morphology and large-scale environment. Only theses data will allow us to establish a complete census of the condensed baryons in the systems, to characterise the dynamical structure of the galaxy groups and filaments and to quantify the CGM metal enrichment as a function of stellar mass. Together, these observations will provide fresh clues on the baryon cycle, a key component of galaxy formation and evolution.

The project is part of an international team effort to study the cosmic baryon cycle through multi-wavelength observations and simulations of galaxies. The student will be part of a large team of scientists with a huge accumulated experience on studies of galaxy evolution.