Poster abstract details

Understanding galaxy sizes in the light of the galaxy-halo connection
Lorenzo Zanisi, Francesco Shankar, Mariangela Bernardi


The physical processes at play in shaping the sizes of galaxies are a matter of intense debate and current models of galaxy evolution struggle to reproduce both the observed size evolution and size distribution of galaxies. However, several studies have now shown that some of the properties of galaxies and those of their dark matter haloes are closely intertwined. We implement this idea in a simple semi-empirical model in which galaxy sizes are assigned according to their dark matter halo size. We compare our model results to data from CANDELS and SDSS and we show that this simple assumption is enough to reproduce both the size evolution and the size distribution of galaxies, provided that the relation between galaxy and halo size has an intrinsic scatter that varies with galaxy stellar mass as well as galaxy morphology. We give a physical interpretation of this result.