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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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