Arbeiten
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Diplom Arbeiten |
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Diplomarbeiten an der Sternwarte Bonn bei Dr. Michael Hilker |
| (offizieller Betreuer: Prof. Dr. Klaas de Boer) |
| (Stand Mai 2004) |
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Die folgenden Diplomarbeitsthemen sind in Englisch beschrieben, da die
gesamte Fachliteratur in dieser Sprache verfasst ist. D.h., der
Diplomand kommt nicht darum hin, sich in sein Thema mit Hilfe englischsprachiger
Literatur einzuarbeiten. Selbstverständlich steht ihm dabei die
Hilfe aller Mitarbeiter der Sternwarte zur Verfügung.
Die angegebenen Themen gehören zur extragalaktischen Astronomie wie auch zur galaktischen Astronomie. Bei den ersten beiden Themen handelt es sich um die Erforschung der Zwerggalaxienpopulationen in nahen Galaxienhaufen und der kinematischen Eigenschaften in den Zentren der Haufen. Das letzte Thema behandelt die chemische Zusammensetzung des Halos unserer Galaxie. Wer sich für eins der folgenden Diplomthemen interessiert, vereinbart bitte mit mir einen Termin zur einer informellen Vorbesprechung: Telefon: 0228-733669, email: mhilker@astro.uni-bonn.de) |
| 1) | Kinematics and Abundances of Dwarf Galaxies in the Hydra I Galaxy Cluster |
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Description: A photometric survey of the central region of the Hydra I
galaxy cluster with the VLT (FORS1) resulted in the discovery of dozens of new
dwarf member candidates. The analysis of the allows the study of
the faint end of the galactic luminosity function and the spatial distribution
of dwarf galaxies in the cluster as a function of their morphological type.
Going one step further, only the addition of spectroscopic informations,
as radial velocity and chemical abundance, allows a deeper insight into the
connection of the dwarf galaxy population to the cluster as a whole.
Therefore multislit spectroscopy has been taken for selected dwarf member
candidates and nuclei. Radial velocities will be used to confirm the cluster
membership and to construct a dynamical model of the dwarf galaxy population
in Hydra I. Metal abundance indices will help to gain insight into the
enrichment history of dwarf galaxies and their nuclei.
The diploma thesis would include a collaboration with Steffen Mieske and Polo Infante at the Universidad Catolica, Santiago, Chile. Data: Low resolution spectra, taken with LDSS2 on Magellan I at Las Campanas, Chile
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| 2) | Virgo Dwarf Galaxies and their Nuclei |
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Description: Little is known about the faint end of the galactic
luminosity function (does it truly drop off at M_V ~ -8?) -- the realm of
the dwarf spheroidal galaxies. Large numbers are expected in clusters such as
Virgo, but have not yet been searched for with large CCD arrays. In addition,
is is still unclear what the nuclei (present in many brighter dE galaxies)
truly are -- perhaps globular-cluster-like systems?
In order to effectively study these objects, a large (> 10 square degree)
section of the Virgo cluster core has been imaged with the CFH12K camera
to (a) search for the low-L dSph systems, and thus find the definitive faint
end of the galactic LF, (b) study the nuclei (magnitudes, colours)
in many (>100) of the brighter dE galaxies in order to gain insight as to
what the nuclei really are, and (c) look for evidence for possible `disrupted
nuclei' in the GC system of the central cD galaxy M87. This dataset would
provide information on the presence of (and formation/evolution of)
dE/dSph galaxies in large clusters.
The diploma thesis would include a collaboration with Pat Durrell, Canada. Data: Wide field imaging in the V and I filters, taken with the Canadien French Hawaii Telescope (CFHT) at Mauna Kea, Hawaii
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| 3) | Abundance determinations in globular clusters with different formation histories |
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Description:
Some globular clusters in the Milky Way probably have an extragalactic
origin. They were brought to our Galaxy by the accretion of dwarf galaxies.
Thus they were originally formed in a very different environment.
In order to learn how this environment influences the chemical evolution of
a stellar system, the abundance pattern of subgiant and red giant stars in
clusters which are believed to have formed in widely different locations
shall be determined and compared with each other. A large set of spectra
(available in August 2004) will allow for a very precise differential study of
different populations of globular clusters, thus yielding constraints on
differences in the inital mass functions and star formation rates of the parent
gas clouds in which they formed.
The diploma thesis will be supervised by Philip Willemsen and Michael Hilker. Data: Medium resolution spectra in the range 3700-5700Å, taken with the VLT+FORS2 telescope at Paranal, Chile
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Diploma Topics |
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