Detailed stellar populations of dwarf elliptical galaxies

Abstract

Dwarf Elliptical Galaxies (dEs), the low luminosity and low surface brightness population of the Early Type Galaxy (ETGs) class are found in high-density environments and are very rare in isolation. Although these objects are the numerically-dominant types of galaxies in the Universe, their origin and evolution still remain a matter of debate since they are intrinsically faint and their structure is very complicated. In this PhD thesis, we define the physical properties of dEs in the Virgo and Fornax cluster by focusing on their elemental abundances and stellar populations as analysed using integral field unit and long-slit spectroscopy. The aim of this work is to help a better and more complete understanding of star formation histories of dwarf ellipticals using abundance ratios. Measured abundances of various elements allow us in principle to understand which enrichment processes have been more effective throughout the various epochs of galaxy formation, because different types of supernovae, which are responsible for the chemical enrichment of the galaxies, have different timescales and yields. We present a new set of high-resolution indices which makes it possible, for the first time, to study in detail individual element abundance ratios of many elements in small, unresolved galaxies outside the Local Group. We perform a detailed stellar population of 8 dEs in Fornax cluster using the newly defined line indices of this thesis and measured their abundance ratios.