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OATS-DAUT SEMINAR
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Speaker: Gustavo Lanfranchi (Universidade de Sao Paulo)

Title: Chemical Evolution Of Local Group Dwarf Spheroidal Galaxies

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Abstract:
The chemical evolution of six Local Group Dwarf Spheroidal Galaxies will be discussed based on studies performed with an one zone chemical evolution model which is able to reproduce the main observational constraints of these galaxies. The model adopts up to date nucleossynthesis prescriptions from both types of supernovae and intermediate massive stars and is able to follow in detail the evolution of the abundances of a series of chemical elements. Several abundance ratios, the total mass, the gas mass and the metallicity distribution predicted by such models fit very well the observed data. In our scenario, the evolution of the dSph are controlled mainly by a low star formation efficiency and by very intense galactic winds. The low star formation in these galaxies gives rise to the low observed metallicities, whereas the intense galactic winds are responsible for the low final gas mass and for the sharp decrease observed in the abundance ratios. Besides that, both parameters help defining the shape of the stellar metallicity distribution, which can be used to constrain the star formation histories of these galaxies.
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