The cloud-scale baryon cycle across the nearby galaxy population
Melanie Chevance (Heidelberg University)
November 21, 2022
Abstract: Galaxies are in constant evolution, driven by the cycle of matter within them: gas clouds assemble and collapse, stars form within them, matter and energy are redistributed in the galaxy through stellar feedback and turbulence. The physical processes driving this cycle occur on small scales but govern the evolution of entire galaxies. In turn, the large-scale evolution of galaxies across space and time directly affects the environment from which stars form. It is one of the big unanswered questions in modern astrophysics which processes drive this multi-scale cycle and what its quantitative characteristics are. I will present the first systematic characterisation of the evolutionary timeline between molecular gas clouds, stars and feedback in galaxies. I will show that star formation is fast and inefficient: gas clouds are quickly destroyed (within 1-5 Myr) by radiation and winds from the young stars born within them, limiting the efficiency of the gas-to-star conversion to 2-10%. Such measurements are key to overcome the main limitation of current simulations of galaxy formation and evolution.