TY  - GEN
ID  - heidok19787
Y1  - 2015///
TI  - Reading the Chemical Evolution of Stellar
Populations in Dwarf Galaxies
AV  - public
N2  - In this thesis I present observations and analyses addressed to understand the individual evolution
of dwarf galaxies and the interdependency with their local environment. My study focuses
on the Fornax dwarf spheroidal galaxy, which is the most massive galaxy of its type in the Local
Group, hosting stars with a broad range in age and metallicity. Additionally, it is the only intact
dwarf spheroidal with an own globular cluster system. Therefore, it provides a superb laboratory to
gain insights about the formation and chemical enrichment processes of baryonic matter in Galactic
halos. In particular, I have used individual alpha-element abundances obtained from high-resolution
spectra to characterize, for the first time, the chemical evolution of Fornax over its entire age and
find a surprisingly low early chemical enrichment efficiency with respect to other dwarf galaxies.
Comparison with chemical evolution models show that Fornax must have experienced a systematically
increasing star formation efficiency with time in order to bring the observations in agreement
with the model predictions. One emerging evolutionary scenario is that Fornax experienced major
accretion events in the past, so that its current properties are not indicative of the chemical enrichment
environment at ancient times. A similar chemical analysis for the globular cluster H4 and
nearby field stars in Fornax reveals, that H4 is depleted in all analyzed alpha-elements and falls on
top of the observed field star [alpha/Fe] sequence, while its abundance pattern disagrees with the properties
of Milky Way halo field stars and clusters. Thus, I propose a chemical enrichment coupling
of the globular cluster population and field stars in Fornax. This finding provides tight constraints
on the origin of alpha-depleted globular clusters in the Milky Way and will enable the chemical enrichment
characterization of distant galaxies from integrated-light cluster analysis where field stars
are too faint for detailed chemical analysis.
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/19787/
A1  - Hendricks, Benjamin Thomas
ER  -