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Bachelor’s & Master’s Theses
at the University Observatory

For general questions please contact A. Riffeser (arri@usm.lmu.de).
Some bachelor’s projects can also be extended in scope and assigned to two students to work on the project together.

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)

Project 1.1 (Bachelor’s project): Development and measurement of optical components and detectors for new instruments at the Wendelstein observatory (U. Hopp hopp@usm.lmu.de, F. Grupp, C. Gössl, F. Lang)

Several new instruments and optical measuring devices are being developed for the new 2-m Wendelstein telescope. Optical components such as filters, glass fibres, lenses and electronic detectors (CCDs) have to be measured and tested. Projects in these areas can be assigned according to the student’s interests. They include lab work in Munich, development of small control scripts, as well as analysis and documentation of the measurements.

Project 1.2 (Bachelor’s project): Literature work relating to astronomic instrument construction (U. Hopp hopp@usm.lmu.de, F. Grupp)

Documentation of new developments in instrument and telescope construction — including adjustment methods and environmental influence — are often only to be found in poorly available conference proceedings. The task is to critically look at and compile comments spread over many different courses. Current projects focus on SPIE contributions to wind loads of telescopic mounts, the cleaning and coating of telescope and instrumentation mirrors, and methods of mirror adjustment (e.g., Hartmann analysis).

Project 1.3 (Bachelor’s project): Development of instrument control software (C. Gössl cag@usm.lmu.de)

Prerequisite for this project is sound knowledge of and interest in programming. The construction of the instrumentation for the 2-m Wendelstein observatory telescope makes the development of subunit control software necessary. Task: Document the physical approach, the software solution as well as the integration of both in the whole system. Example: Automation of test rigs in the observatory labs or effective organisation of standard star data sets of the 40-cm telescope.

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 (Master’s project): 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 (Bachelor’s project): Comoving frame radiative transfer in expanding atmospheres (J. Puls uh101aw@usm.lmu.de)

The physical parameters of hot stars are mainly determined from a comparison of observed and synthetic spectra, where the latter are calculated by means of so-called model atmosphere codes. One of the most important components of these simulations is the line radiation transport, which, because of the expansion of the outer atmospheres of these stars (= stellar winds), is conveniently solved in the comoving frame and described by a (hyperbolic) partial differential equation. In the numerical codes developed in our institute, a so-called implicit scheme is used, which is characterized by high stability, but relatively low accuracy. In this bachelor’s thesis, an alternative semi-implicit method allowing for a principally higher accuracy shall be implemented, tested, and compared with the implicit method.

Project 2.3 (Master’s project): 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 2.4 (Master’s project): 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 2.5 (Bachelor’s project): Correlation of X-ray emission and fundamental parameters of hot stars (T. Hoffmann hoffmann@usm.lmu.de, A. W. A. Pauldrach)

A possible correlation between the intensity of the X-ray emission and fundamental stellar parameters is to be investigated. This entails the simultaneous comparison of a sample of existing observed X-ray and UV spectra of hot stars with model spectra which will need to be calculated. This analysis will help to better understand the dynamic processes that lead to the production of X-ray radiation in these atmospheres. Programming experience in Fortran is required.

Project 2.6 (Bachelor’s project): Calculation of mass loss rates of extremely massive stars (A. W. A. Pauldrach uh10107@usm.lmu.de, T. Hoffmann)

Using a largely already existing program, mass loss rates are to be calculated for a model grid of extremely massive stars such as might arise in dense star clusters through collisions and merging processes. Such stars could conceivably have masses of up to a few thousand solar masses (see http://www.usm.uni-muenchen.de/people/adi/RevBer/HotStars-OForT-Mod.html). The data obtained represent important quantities for describing the evolution of such objects and to compute their spectra, and thereby check for the possible existence of such stars in present-day starburst clusters. Programming experience in Fortran is required.

3. Galaxies

H. Lesch (lesch@usm.lmu.de), R. Saglia (saglia@usm.lmu.de), J. Thomas (jthomas@mpe.mpg.de), OPINAS Group (http://www2011.mpe.mpg.de/opinas/education/PhD_Projects/phd_thesis_topics.html)

Project 3.1 (Bachelor’s project): Dynamos in galaxies (H. Lesch lesch@usm.lmu.de)

All galaxies are magnetized. Where do galactic magnetic fields come from, how are they maintained and how are they structured? These are the questions we wish to answer. In this project we will develop a model for the amplification of galactic magnetic fields based on analytic calculations.

Project 3.2 (Bachelor’s project): Propagation of cosmic rays in the Galaxy (H. Lesch lesch@usm.lmu.de)

Cosmic rays represent a small but high-pressure part of the interstellar medium. Through their pressure on the magnetic fields, cosmic rays contribute considerably to the galactic dynamo. In this project we will analyse the properties of Galactic cosmic rays and their impact on gamma-ray emission.

Project 3.3 (Bachelor’s project): The age of a galaxy (R. Saglia saglia@usm.lmu.de)

How do we measure the age of a galaxy? The bachelor’s thesis should summarize the methods that have been developed to reach this goal and their uncertainties. If there is enough time, one can also derive a spectroscopic age from data available for a selected number of objects.

Project 3.4 (Bachelor’s/Master’s project): 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 answers to these questions will be tested and implemented.

Project 3.5 (Bachelor’s project): The masses of supermassive black holes at the centers of galaxies (R. Saglia saglia@usm.lmu.de)

How do we measure the masses of supermassive black holes at the centers of galaxies? What are their uncertainties? How much mass is hidden in supermassive black holes? The results of the recent research should be critically summarized and discussed.

Project 3.6 (Master’s project): 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 is the reduction and analysis of these data, their dynamical modeling and the determination of the dark matter density in these objects.

4. Cosmology

J. Weller (weller@usm.lmu.de), R. Saglia (saglia@usm.lmu.de), J. Mohr (jmohr@usm.lmu.de)

Project 4.1 (Bachelor’s project): Distances to supernovae in various cosmological models (J. Weller weller@usm.lmu.de)

The student will derive the correlation between distance and red shift for different Friedmann Models. Boundary conditions to cosmological parameters will be derived by comparison with supernova data. These analyses are made with the aid of so-called Monte Carlo Markov chains. If there is enough time, the analysis can be extended to models with extra dimensions.

Project 4.2 (Bachelor’s project): The size evolution of galaxies (R. Saglia saglia@usm.lmu.de)

The size of a galaxy changes during its life. Goal of the thesis is to summarize the results of the last years of published research. How do we measure the size of a galaxy? What is the rate of change of the size of a galaxy with time? Does it depend of the mass of the galaxy? What are the mechanisms that drive the size change of galaxies?

5. Gravitational Lensing

S. Seitz (seitz@usm.lmu.de), A. Riffeser (arri@usm.lmu.de)

6. Numerical 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 numerical 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.

Last updated 2017 March 14 09:32 by Webmaster (webmaster@usm.uni-muenchen.de)