deutsche Version
Master’s thesis projects
at the University Observatory
For general questions please contact A. Riffeser (arri@usm.lmu.de).
1. Instrumentation and observational projects
U. Hopp (hopp@usm.lmu.de),
C. Gössl (cag@usm.lmu.de),
A. Riffeser (arri@usm.lmu.de),
F. Grupp (fug@usm.lmu.de),
A. Hess (achim@usm.lmu.de),
F. Lang-Bardl (flang@usm.lmu.de)
Project 1.1:
Development of instrument control systems with Beckhoff SPS for large telescope systems
(M. Häuser mhaeuser@usm.lmu.de,
A. Hess achim@usm.lmu.de)
Diese Masterarbeit setzt Interesse an elektronischen Steuerungen und
Sensorik voraus. Vorkenntnisse in Elektronik (u. U. entsprechende
Master- oder Bachelorvorlesungen) und SPS-Technologien im besonderen
sind von Vorteil. Im Rahmen des Baus des MICADO-Instruments
für das 39-m-EELT-Teleskop in Chile sind diverse Mechanismen
und elektronische Steuerungskomponenten zu entwickeln, bauen und zu
testen. Mechanismen und Sensorik müssen in einem Test-Kroystat
(~80 K) an der USM getestet und von Beckhoff-SPS gesteuert
werden. Die Arbeit umfasst die Konzipierung, Durchführung und
Dokumentation von Tests diverser Hardware bei Raumtemperatur und bei
~80 K in unserem Kryostaten. Ergebnisse müssen aufbereitet
werden um im Rahmen des MICADO-Projekts von anderen internationalen
Konsortiumspartnern verwendet zu werden. Als Steuerungselektronik
werden Beckhoff-SPS eingesetzt. Zusätzlich kann je nach
genauem Thema ein rein astrophysikalisches Beobachtungs-
und/oder Datenauswertungsprojekt in Zusammenarbeit mit dem
Wendelstein-Observatorium absolviert werden.
2. Stars and planets
T. Preibisch (preibisch@usm.lmu.de),
J. Puls (uh101aw@usm.lmu.de),
A. W. A. Pauldrach (uh10107@usm.lmu.de),
T. Hoffmann (hoffmann@usm.lmu.de)
Project 2.1:
Multi-wavelength observations of star formation regions
(T. Preibisch preibisch@usm.lmu.de)
Students can carry out investigations as part of an ongoing project,
e.g., correlation of object lists in different wavelengths ranges
(from X-ray to the sub-mm regime).
Project 2.2:
Model atmospheres and synthetic spectra for Wolf-Rayet stars
(J. Puls uh101aw@usm.lmu.de)
The model atmosphere code “Fastwind”, developed by
our group, is one of the world’s most widely used codes for
calculating the optical/IR spectra from massive stars of spectral
type O and B. The project presented here aims at stepwise extending
the code so that the spectra of so-called Wolf-Rayet stars can be
synthesized. The main difference of the atmospheres of these Wolf-Rayet
(WR) stars in comparison to those of “normal” stars is
a significantly higher wind density (practically all optical lines
are formed mainly in the wind) and a different chemical composition:
in most cases, the helium and nitrogen abundances (products of the
CNO cycle) are greatly increased, whilst the hydrogen abundance is
dramatically reduced (until zero). The work presented here requires
a strong interest in the implementation of numerical methods.
Project 2.3:
3-D radiative transfer in stellar winds of hot stars
(J. Puls uh101aw@usm.lmu.de)
In recent years, substantial progress in the theoretical
description of stellar winds from hot stars has been achieved,
particularly with regard to the influence of fast rotation and
magnetic fields. These theoretical predictions must now be tested by
means of observed spectra, which requires a departure from the
spherically-symmetric geometry used in current diagnostic methods.
Accounting for future developments and already existing computing
resources, a treatment in 3-dimensional Cartesian geometry is
beneficial. This master’s project shall enable the spectrum synthesis of
wind lines, based on such a geometry and a so-called two-level atom,
whilst two different methods (short or long characteristics) shall be
compared. The achieved accuracies can be determined, for special
cases, by comparison with already existing 1-D spherically symmetric
calculations. This project constitutes a first building block for
models and spectrum synthesis calculations in three-dimensional
expanding atmospheres, and a future coupling with hydrodynamic models.
Project 2.4:
Period-luminosity relation of long-period variable stars in M31
(J.Snigula snigula@usm.lmu.de,
A. Riffeser arri@usm.lmu.de)
Pulsating variable stars are known to follow a relation between the
duration of the pulsation, the period, and their mean luminosity.
These so-called period-luminosity relations are one of the central
tools to get reliable distances of nearby galaxies.
Based on theoretical and observational arguments, there has been a
long discussion if these relations depends on galactic properties like,
e.g., the metallicity of the parent generation of the pulsating stars.
Long-period variable stars have, compared with short-period variable
stars like Cepheids or RR-Lyrae, been studied only sparsely.
Only in the last years a period-luminosity relation was published
based on the OGLE data, for the Magellanic clouds (which are very
close by and metal poor).
The goal of this Master’s thesis project would be to check
the long-period variable stars found in the Pandromeda survey of the
metal-rich M31 galaxy, and to build using photometry obtained from
publicly available data the period-luminosity relation for these stars.
Finally these results should be compared with the published results
for the Magellanic clouds.
3. Galaxies
H. Lesch (lesch@usm.lmu.de),
R. Saglia (saglia@usm.lmu.de),
J. Thomas (jthomas@mpe.mpg.de),
OPINAS Group (http://www.mpe.mpg.de/1761897/Master-_und_Doktorarbeiten)
Project 3.1:
Dynamical modeling of stellar disks
(R. Saglia saglia@usm.lmu.de,
J. Thomas jthomas@mpe.mpg.de)
Three-dimensional galaxies are often modeled using the Schwarzschild
approach.
One computes stellar orbits in a given gravitational potential and
superposes them to reproduce the available dataset.
The modeling of two-dimensional objects like galaxies with stellar
disks poses some yet unsolved questions.
How well can one compute the gravitational potential using spherical
harmonics?
What is the optimal amount of regularization?
How well can one describe real galaxies?
During the thesis project answers to these questions will be tested
and implemented.
Project 3.2:
Dark Matter in dwarf elliptical galaxies
(R. Saglia saglia@usm.lmu.de)
Giant elliptical galaxies are embedded in massive dark matter halos.
Not much is known, however, about the dark matter halos of dwarf
ellipticals, because their low velocity kinematics are difficult
to measure.
Thanks to our new high-resolution two-dimensional spectrograph VIRUS-W
we were able to obtain high quality spectra for a number of dwarf
ellipticals in the Virgo cluster.
Goal of the Master’s thesis project is the reduction and analysis
of these data, their dynamical modeling and the determination of the
dark matter density in these objects.
4. Cosmology, large-scale structure, and gravitational lensing
J. Weller (weller@usm.lmu.de),
R. Saglia (saglia@usm.lmu.de),
J. Mohr (jmohr@usm.lmu.de),
S. Seitz (stella@usm.lmu.de),
A. Riffeser (arri@usm.lmu.de),
OPINAS Group (http://www.mpe.mpg.de/1761897/Master-_und_Doktorarbeiten)
Project 4.1:
Comparing simulated and observed red-sequence clusters
(S. Seitz stella@usm.lmu.de,
K. Dolag dolag@usm.lmu.de)
The majority of galaxies in clusters are “red” galaxies (S0
or elliptical galaxies), i.e., galaxies with no ongoing star formation.
This makes them form a “red sequence” in color-magnitude
space.
In multi-band photometric surveys (e.g., Dark Energy Survey DES) one
sucessfully identifies clusters of galaxies by their red-sequence
galaxy population, and estimates the (photometric) redshifts for
clusters using the colors of their red galaxies.
The number of red galaxies of each cluster is used to define its
“richness” (a quantity strongly related to the total mass
of the cluster).
For many purposes in cosmology one would like to relate the
observationally identified “red sequence clusters” to
clusters numerically simulated within the framework of structure
formation.
For example, one would like to know how cluster mass and cluster
richness scales, what the scatter is, and how much dark matter
is associated with individual red galaxies (as a function of the
luminosity and position within the cluster).
The goal of this project is to apply the observers’
cluster-finding technique to simulated clusters and to derive a
catalog with cluster richness, their red-sequence member galaxies,
and dark matter halo masses of individual member galaxies.
These findings can then be compared to results from observations or
can be used to predict the outcome of ongoing and future observations.
Project 4.2:
Cluster mass reconstruction with the weak gravitational lensing effect
(S. Seitz stella@usm.lmu.de,
T. Varga vargatn@usm.lmu.de)
By their (dark and luminous) matter components clusters of galaxies
distort light bundles traversing them.
This so called weak gravitational lensing effect alters the shapes
of background galaxies and aligns their major axes preferentially
tangentially to the foreground clusters centers.
One can invert the relevant relations to derive mass maps for galaxy
clusters, to measure their projected profiles and “total”
masses.
We offer projects on this topic, where either data from our own
Wendelstein 2-m telescope are taken or where public data, or data from
the Dark Energy Survey DES, are used.
Project 4.3:
Analyzing the strong lensing effect in HST-clusters
(S. Seitz stella@usm.lmu.de,
A. Monna amonna@usm.lmu.de)
Towards centers of clusters of galaxies the projected matter
density can become large enough that objects in the background of
such clusters of galaxies are mapped into multiple images and giant
gravitational arcs.
The analysis of this so-called strong gravitational lens effect yields
the most precise astrophysical mass measurements at cosmological
distances.
In addition one can constrain the amount of dark matter (i.e., the
size of dark matter halos) associated with galaxy cluster members.
In this way one can measure the cluster subhalo mass function and
the amount of dark matter stripped when galaxies fall into clusters
and pass their high density cores.
5. Computational and theoretical astrophysics
A. Burkert (burkert@usm.lmu.de),
B. Ercolano (ercolano@usm.lmu.de),
K. Dolag (dolag@usm.lmu.de)
Bachelor’s and Master’s thesis projects in the field of computational and theoretical astrophysics
can generally be offered from the following areas:
- Structure of the turbulent interstellar medium (ISM) and the formation of molecular clouds
- Formation of planets, stars, and stellar clusters
- Stars and their influence on the surrounding interstellar matter
- Radiative transfer
- Formation and evolution of galaxies in a cosmological context (local galaxies to high redshifts,
galaxy clusters, cosmic web, black holes, self-regulating star formation)
- Galactic dynamics
- Active galactic nuclei (AGN)
- Origin and nature of the gas cloud G2 near the Galactic center
- Structure and formation of dark-matter halos
- Magnetic fields and their role on small to cosmic scales
- Application and development of simulation software on parallel CPUs and GPUs (graphics processors);
our hydrodynamic codes are particle- (SPH/N-body) or grid-based, or based on moving-mesh or meshless methods
- Software for three-dimensional data visualization
Specific subjects are usually selected from the context of current research projects.
More information on ongoing and completed projects can be found on the
home page of the CAST group.
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