***********************************************************
OATS-DAUT SEMINAR
***********************************************************

Speaker: Andrea Marcolini (University of Bologna)

Title: Hydrodynamical simulations of ISM pollutions by SNIIs and SNIs in dwarf spheroidal galaxies

***********************************************************
Abstract: The small dynamical mass of dwarf spheroidals means that the interstellar medium (ISM) binding energy is small compared to the energy released by several supernovae, which leads the high metallicity spread and relatively high metallicity derived for these galaxies puzzling. I present preliminary results of 3-D hydro simulations of the ISM evolution in dwarf spheroidal galaxies undergoing star formation for the first time. The star formation is assumed to occur in a sequence of instantaneus bursts separated by quiescent periods. Different models are made changing the number and the intensity of the bursts in such a way that the final mass of the formed stars remains the same. We follow the enrichment of the ISM taking into account the contribution of both type Ia and II supernovae. The aim of our models is to find a star formation history compatible with the observed spread of stellar age and metallicity in such galaxies and to reproduce the observed mass-metallicity relation. In general we are able to reproduce the metallicity distribution function (MDF) of the stars, i.e. the mass fraction of the stars as a function of [Fe/H] and the [O/Fe] vs. [Fe/H] plot. This last plot is very useful because can discriminate the different contribution of SNII and SNIa.
***********************************************************