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Bachelor’s & Master’s thesis projects
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), A. Hess (achim@usm.lmu.de), F. Lang-Bardl (flang@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-Bardl)

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): Development and tests of electronic control systems for large telescopes (M. Häuser mhaeuser@usm.lmu.de, A. Hess achim@usm.lmu.de)

Diese Bachelorarbeit setzt Interesse an elektronischen Schaltungen voraus. Im Rahmen des Baus des MICADO-Instruments für das 39-m-EELT-Teleskop in Chile sind diverse Mechanismen und elektronische Steuerungskomponenten zu bauen und zu testen. Technologien und Mechanismen müssen bei Raumtemperatur an der USM getestet werden. Die Arbeit umfasst die Durchführung und Dokumentation von Tests diverser motorisierter und sensorischer Hardware bei Raumtemperatur zur Vorbereitung auf Tests bei 80 K in unserem Kryostaten. Hierzu gehört beispielsweise auch die Automatisierung von Testständen in den Laboren der Sternwarte. Es werden sowohl komplett selbst entwickelte Elektronikkomponenten verwendet, als auch industrielle Standardtechnologien wie CAN-BUS-Controller und SPS-Steuerungen (Vorwissen wünschenswert aber nicht notwendig). Zusätzlich kann je nach genauem Thema ein rein astrophysikalisches Beobachtungs- und/oder Datenauswertungsprojekt in Zusammenarbeit mit dem Wendelstein-Observatorium absolviert werden.

Project 1.3 (Master’s project): 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.

Project 1.4 (Bachelor’s project): Characterization of the coronograph at the Wendelstein observatory (U. Hopp hopp@usm.lmu.de, F. Grupp)

Analyse and document the properties of the telescope regarding imaging and spectroscopy of the sun in white light, in Hα, as well as in spectral observations. A number of student lab manuals may be drafted in the course of this project.

Project 1.5 (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 1.6 (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): Massive star evolution with MESA (J. Puls uh101aw@usm.lmu.de)

The evolution of massive stars is in many phases (even relatively close to the zero age main sequence – ZAMS) not yet or only poorly understood, mainly due to the effects of mass loss and rotation, and because in conventional simulations multidimensional effects are often approximated by simple 1-D diffusion approaches. Therefore, our working group (including many international collaborators) tries to check and constrain the predictions of such stellar evolutionary calculations, by means of so-called quantitative spectroscopy. To perform corresponding own simulations and tests, the open-source stellar evolution code MESA has proven to be an excellent working tool. The aim of the suggested Bachelor’s thesis project is, on the one hand, to perform evolutionary calculations for different mass ranges by means of MESA, and to compare the outcome with alternative calculations from other codes. On the other hand, appropriate adapters shall be developed, which enable a fast and clear visualization of the various output data.

Project 2.3 (Bachelor’s project): Further development of a program package for the automatic analysis of stellar spectra from massive stars (J. Puls uh101aw@usm.lmu.de)

To investigate the actual status and the evolution of massive stars, and to understand and quantify the interaction with their environment, these stars are studied by means of so-called quantitative spectroscopy, i.e., by comparing observed and synthetic spectra. The latter are derived using stellar atmosphere models. Since in recent years large samples of massive star spectra were secured, an automatic analysis is inevitable. To this end, our (internationally connected) working group uses comprehensive grids of atmospheric models, and stellar parameters are derived from a best fit of synthetic and observed spectra. The basic methods have already been developed, however the a-posteriori distributions of the derived parameters are not yet sufficiently quantified. The aim of this Bachelor’s thesis project is to link the existing codes with an MCMC method (Markov Chain Monte Carlo) to derive such distributions. Programming experience and Python skills would be beneficial.

Project 2.4 (Master’s project): Synthetic infrared spectra of massive stars (J. Puls uh101aw@usm.lmu.de)

The model atmosphere code developed by our working group, “Fastwind”, is one of the world’s most used codes to synthesize the optical and IR spectra of massive stars of spectral types O and B. In recent years, a comprehensive revision of this code has been performed, which among other features also allows to model the ultraviolet range. This new program version, however, has not yet been adapted to calculate the IR range of the spectrum, where just this range is of highest relevance for new and future large telescopes (JWST, ELT). The aim of the suggested Master’s thesis project is, in a first step, to adapt the new “Fastwind” version so that the IR range can be satisfactorily synthesized, including careful tests. A comparison with results from the former program version is mandatory. In a second step, our atomic database shall be extended so that high precision IR spectroscopy of elements different from H and He becomes possible. The work suggested here requires a strong interest in working with and implementing of numerical algorithms.

Project 2.5 (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 2.6 (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 2.7 (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.

Project 2.8 (Master’s project): 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.

Project 2.9 (Bachelor’s project): The future of astronomy – new telescopes for the discovery and characterization of exoplanets (Roberto Saglia saglia@mpe.mpg.de, Christian Obermeier chroberm@usm.lmu.de)

Exoplanet research is a very active scientific area and a new generation of telescopes is currently being developed in order to study several of their aspects and add more discoveries. The aim of this project is to provide an overview over telescopes that are already in the planning stage and then give an outlook of the future development of astronomical observations.

Project 2.10 (Bachelor’s project): The statistical distribution of planets – an overview (Roberto Saglia saglia@mpe.mpg.de, Christian Obermeier chroberm@usm.lmu.de)

Since the first discovery of an exoplanet in orbit around another main-sequence star in the year 2000, there has been a fast-growing number of exoplanet discoveries. Detected by several number of methods, their properties are quite diverse. Since the number of known exoplanets is now in the thousands it is now possible to make statistical assessments of their occurrence rate for given stellar types and the planet’s orbital periods. The aim of this project is to collect all of the current data, present each detection method and then discuss the results and their possible differences based on the detection method.

Project 2.11 (Bachelor’s project): The Rossiter-McLaughlin effect – measuring the stellar rotation axis through transits (Roberto Saglia saglia@mpe.mpg.de, Christian Obermeier chroberm@usm.lmu.de)

The Rossiter-McLaughlin effect (RME) has been known for decades and was initially proposed for the study of eclipsing binaries. Using this effect, the primary star’s rotation axis can be determined and this effect could first be applied to planet transits only a few years ago. The Wendelstein facility will soon be able to observe and measure this effect as one of very few observatories by using the FOCES instrument. The aim of this project is to describe the RME by compiling the according literature and then give an overview of the current results and their interesting implications for planet formation.

Project 2.12 (Bachelor’s project): Super-Earths – properties and occurrence rates (Roberto Saglia saglia@mpe.mpg.de, Christian Obermeier chroberm@usm.lmu.de)

Super-Earths, rocky planets with radii of more than twice of Earth’s, are unknown in our own Solar system and are a distinct population of planets. The aim of this project is to describe this population, including the detection methods used for their discovery, and then provide an overview of their occurrence rate. Then, the results of their – rapidly increasing – research should be compiled.

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 (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 project 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 project 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 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 (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?

Project 4.3 (Master’s project): 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 4.4 (Bachelor’s project): Studying the strong lensing effect of galaxies using HST data (S. Seitz stella@usm.lmu.de, A. Riffeser arri@usm.lmu.de)

Due to the strong gravitational lens effect galaxies can map galaxies in their background in so-called Einstein rings or multiple images. You will study how the (dark plus luminous) matter in a foreground galaxy has to be distributed to reproduce the observed image configuration. You will use a public lens-source-reconstruction code and study several systems observed with the Hubble Space Telescope (HST).

Project 4.5 (Master’s project): 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 4.6 (Master’s project): 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.

Project 4.7 (Master’s project): Density Split Statistics (S. Seitz stella@usm.lmu.de, O. Friedrich oliverf@usm.lmu.de)

The evolution of the cosmic density field encodes powerful information on the laws of gravity as well as the initial conditions of the universe. So far, most experiments that quantify the large-scale structure of the universe only measured 2-point statistics of the density field. This means that they measured the amplitude of density fluctuations as a function of scale. This provides only a limited view of the large-scale structure and hence limited cosmological information. Within the Dark Energy Survey (DES) Collaboration we established a new method of analyzing the large-scale structure of the universe: Density Split Statistics (DSS). This method closes a major gap in current studies of the large-scale structure: it can disentangle gravitational non-linearities from non-trivial features in the relation between galaxies and matter! The reason for this is that DSS is sensitive to the skewness of density fluctuations (as opposed to only the amplitude). We are looking for a Master student with excellent mathematical skills to complement our work on density split statistics. This student will first familiarize herself/himself with our publications Friedrich & Gruen et al. (arXiv:1710.05162) and Gruen & Friedrich et al. (arXiv:1710.05045). These describe density splits of the gravitational lensing power spectrum. The student will then transfer our formalism to also incorporate density splits of the galaxy power spectrum.

5. Computational and theoretical astrophysics

A. Burkert (burkert@usm.lmu.de), B. Ercolano (ercolano@usm.lmu.de), K. Dolag (dolag@usm.lmu.de), B. Moster (moster@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.

Last updated 2018 March 12 16:52 by Webmaster (webmaster@usm.uni-muenchen.de)