SPECIAL OAT and DAUT SEMINAR ANNOUNCEMENT - Friday (please note), May 19 at 12: noon

[Gabriella Schiulaz]

****************************************************
                   SPECIAL SEMINAR 
****************************************************

Speaker: Gustavo Lanfranchi (Universidade de Sao Paulo) 

Title: Chemical Evolution Of Local Group Dwarf Spheroidal Galaxies 

Date: Friday, May 19th, 2006 
Time: 12:00 noon 
Venue: Villa Bazzoni (via Bazzoni, 2) -Seminar room, ground floor

*********************************************************** 
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. 
***************************************
Gabriella Schiulaz
segreteria OAT
phone: 040-3199241
schiulaz at oats.inaf.it
segreteria at oats.inaf.it