Seminários de Astronomia – Theoretical and semi-empirical stellar population models: a controlled experiment on empirical versus theoretical stellar libraries

Ministrante: Paula Coelho (IAG/USP).

Resumo: Stellar population synthesis (SPS) models are invaluable to modern Extragalactic Astrophysics. They provide means to extract stellar masses, stellar ages, star formation histories, chemical enrichment histories and dust content of galaxies from their integrated spectral energy distributions, colours or spectra. One source of model uncertainty which has not been properly quantified yet regards the impact of choosing an empirical versus a theoretical stellar flux library to build the SPS models: the first suffers from limited coverage of the parameter space while the second suffer from modelling inaccuracies such as incorrect atomic and molecular opacities. This work aims at studying the effects of this particular choice, specifically by answering three questions: (1) How the known uncertainties in theoretical stellar libraries affect fully-theoretical stellar populations models?}; (2) How the non-ideal coverage of the HR diagram by empirical libraries affect semi-empirical models?} and; (3) How random errors associated to atmospheric parameters translate into the models?}. In this talk I will present our preliminary results on these questions.