DescrizioneName: Bruno Martin Celiz
Institution: IATE / National University of Córdoba, Argentina
Title: A statistical picture of galaxy mass build-up and morphology: Inside-out to outside-in?
Abstract: In the standard lore, disk galaxy formation occurs in an inside-out manner, resulting in older and thicker stellar components being located in the inner regions. This model explains the growth of massive disk galaxies, but its extension to the low-mass end is not as well established. Using the TNG50 cosmological hydrodynamical simulation we study the stellar age radial profile as a function of stellar mass in isolated central galaxies with 7.0 < log M* < 11.0 at redshift z = 0. We found that massive galaxies exhibit the expected “inside-out” build-up pattern, with young stars forming in the outer parts of the disks. Conversely, dwarf galaxies show a much higher star formation rate in central regions (r < 1 kpc), resulting in a positive age radial gradient. We analyze the temporal evolution of the baryonic component (mass, star formation rate, kinematics, and spatial distribution) within a fixed volume (0.15 r200(z = 0)) for each galaxy. We find that misaligned gas accretion and the interplay between star formation and gas density at r > 0.01 r200(z = 0) are the key factors driving the transition from an apparent “outside-in” to the classical “inside-out” age gradient as total stellar mass increases.