Title:  The shape of time: characterisation of the age profiles in low-mass galaxies

Abstract: U-shaped radial age profiles have recently been reported in low-mass galaxies. This type of profile differs from the expected positive radial age gradients of the low-mass regime. In this talk, I aim to shed light into the nature of this U-shaped feature in the age profiles of these systems. We analyse whether there exists any correlation between the properties of the galaxies that exhibit it and the U shape’s characteristics using the Auriga simulations. We find that low-mass galaxies start exhibiting U-shaped age profiles at high z (on average, at z ~ 0.63) that prevail until z=0, with more massive systems developing this feature earlier than their less massive counterparts. We also characterise the environment in which low-mass galaxies with U-shaped age profiles are more commonly found using the IllustrisTNG simulations. We find that galaxies with a U-shaped age profile are mostly central systems (73%) and that 83% of them reside within low-mass halos (M200 < 10^12 Msun). We also find that galaxies exhibiting this feature are located at large distances from galaxy groups but close to cosmic filaments, with a median distance of 265 kpc, whereas those without U-shaped age profiles tend to be located farther away from these structures (351 kpc).