The half mass radius of MaNGA galaxies: Effects of stellar population gradients
Mariangela Bernardi (University of Pennsylvania)
Tuesday 23/09/2025 @ 14:00, Sala Antonio Sollima (IV piano Battiferro)
Stellar populations vary across the galaxy population. However, even within a single galaxy, there are stellar population gradients – e.g., in age, metallicity, chemical enhancement, Initial Mass Function (IMF) – which recent spatially resolved spectroscopic surveys (e.g. MaNGA) are revealing in an unprecedented way. Gradients in the stellar populations of galaxies can result in gradients in the stellar mass to light ratio: for early-type galaxies, M* /L gradients are weak if driven by variations in age and metallicity, but they can be significantly larger if they are driven by variations in the IMF. Larger gradients imply that the distribution of the stellar mass and light are different. I will show that our measurements of IMF-driven M* /L gradients in early-type galaxies suggest that: i) The half mass radius can be significantly smaller (up to a factor of two) than the half light radius; ii) The discrepancy between the dynamical and the stellar mass, based on stellar population estimates, is substantially reduced. These results inform our understanding of how early-type galaxies assembled their mass.