The star formation history of dwarf galaxies: First results of the MAGPOP-ITP

The MAGPOP-ITP is a large observational project of the EU MAGPOP Network. In order to study the star formation history of dwarf galaxies, a total of 60 nights was allocated on the 4 large La Palma telescopes in the framework of an International Time Programme. The programme comprises continuum, Hα and near-infrared imaging and optical spectroscopy of quiescent and star-forming dwarfs in the field and in the Virgo Cluster. All galaxies in the sample are selected to have imaging in the UV (by GALEX) and in the optical (by SDSS), and many have additional data available in the GOLDMine database. The aim of the programme is to study the star formation of dwarf galaxies in function of their environment and dwarf type. In this contribution, I will focus on the results obtained for dwarf elliptical galaxies (dEs) using long-slit optical spectroscopy obtained with the NOT. We derive mean luminosity-weighted ages and metallicities using Lick indices for 25 dEs. The dEs show a large spread in both ages and metallicities, but overall they are younger and less metal-rich than normal ellipticals (Es). The [α/Fe] ratios of the dEs are compatible with solar ratios, or are even slightly underabundant, pointing at prolonged star formation histories for dEs.