New HR-pyPopStar synthesis models: studying dwarf galaxy properties

by Dr Iker Millan Irigoyen (Max Planck Institute for Astrophysics)

Friday Mar 20, 2026, 10:00 AM → 12:00 PM Europe/Madrid

00.303.0 - Aula 13 (Facultad de Ciencias Físicas)

Low-metallicity stellar populations are numerous in the Universe. Either as the remnants of the past history of the Milky Way and similar spiral galaxies or the young low-metallicity stellar populations that are being observed in the local dwarf galaxies or at high-z galaxies recently found with JWST. In order to study those special environments, we developed new high-spectral-resolution models tailored for low-metallicity environments using the state-of-the-art stellar population synthesis code HR-PYPOPSTAR with up-to-date stellar libraries.  We compared the new spectral energy distributions with the previous models of HR-PYPOPSTAR for solar metallicity and with other stellar population synthesis models. We found agreement between all the models in the optical but found several differences between the models in the NIR molecular bands. These intrinsic differences can substantially affect the age, metallicity and mass estimates derived from restframe NIR data, such as those obtained with VLT, JWST. Finally, we analysed a sub-sample of dwarf galaxies from the MaNGA survey and we found that star-forming dwarf galaxies have higher stellar mass - mean stellar metallicity relation than the average dwarf galaxies. These results suggest that dwarf galaxies are very sensitive to sudden changes in the Star Formation History.