LMU logo

University Observatory Munich


Faculty of Physics at the Ludwig-Maximilians-University

USM logoLMU seal
deutsche Version

Bachelor’s thesis projects
at the University Observatory

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

C. Gössl (cag@usm.lmu.de), F. Grupp (frank@grupp-astro.de), A. Hess (achim@usm.lmu.de), F. Lang-Bardl (flang@usm.lmu.de), A. Monna (amonna@usm.lmu.de)

We at any time also offer other projects which are not listed below. Just write an email and describe your interests and skills.

Project 1.1: 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.

2. Stars and planets

T. Preibisch (preibisch@usm.lmu.de), J. Puls (uh101aw@usm.lmu.de), T. Hoffmann (hoffmann@usm.lmu.de)
Project 2.1: 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 2.2: 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 2.3: The future of astronomy – new telescopes for the discovery and characterization of exoplanets (R. Saglia saglia@mpe.mpg.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 2.4: The statistical distribution of planets – an overview (R. Saglia saglia@mpe.mpg.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 2.5: The Rossiter-McLaughlin effect – measuring the stellar rotation axis through transits (R. Saglia saglia@mpe.mpg.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 2.6: Super-Earths – properties and occurrence rates (R. Saglia saglia@mpe.mpg.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.
Project 2.7: Capture of free-floating planetesimals (R. Saglia saglia@mpe.mpg.de, A. Ivlev ivlev@mpe.mpg.de)
Planetesimals are thought to form in gaseous disks surrounding young stars, but the details are poorly understood. An interesting possibility is that planetesimals actually only form from scratch under special circumstances, and most stars simply capture interstellar ones in their gaseous disk, which then trigger the formation of further planetesimals from the solid material in the disk. This project would be to estimate the number of such objects which are captured in the disk of a forming star. Depending on the interest of the student, this could be either calculated using an analytical model of the time-dependent gravitational potential well of the young star, or done numerically by analyzing the gravitational potential of the gas in a simulation.
Project 2.8: Radiative torques on dust grains in the solar system (R. Saglia saglia@mpe.mpg.de, A. Ivlev ivlev@mpe.mpg.de)
Small grains of solid material in space (dust) could be spun up as a result of torques arising from the asymmetric grain structure and/or the anisotropic radiation field. It has been argued that the grains may spin so fast that they are ripped apart by centrifugal force. For this project, the student will study the associated literature to develop an understanding of the size distribution and lifetime of the grains that make up the interplanetary dust cloud. They could then combine this information with existing models of the grain disruption to determine whether centrifugal disruption plays a role in shaping the dust population in our solar system.
Project 2.9: Growth of thick icy mantels on dust grains (R. Saglia saglia@mpe.mpg.de, A. Ivlev ivlev@mpe.mpg.de)
In dense ISM regions, dust grains accrete a surface layer (mantle) of ice. The thickness of this mantle is regulated by a balance between accretion from the surrounding gas, and removal as a result of transient heating following the passage of high-energy charged particles (cosmic rays) through the dust grain. We have recently shown that the balance of these two processes depends on the size of the grain, and the aim now is to explore the mantle growth in different interstellar environments. We are looking for a student to study the mantle growth in various environments with the assistance of an existing code, and to determine how the mantle thickness varies depending on the dust size distribution.
Project 2.10: Gas heating from secondary electrons (R. Saglia saglia@mpe.mpg.de, A. Ivlev ivlev@mpe.mpg.de)
Dense gas in star-forming regions is heated predominantly by cosmic rays. A significant part of the heating is due to secondary electrons – the electrons which are produced when a primary cosmic-ray particle knocks an electron off of a molecule in the gas. We have recently calculated the energy spectrum of such electrons. These electrons lose their energy in a variety of ways, some of which heat the gas, and some the dust. We are looking for a student who will use available models for different energy loss processes to calculate what fraction of the energy goes to gas heating.
Project 2.11: Modelling the temperature distribution of a dense filament (R. Saglia saglia@mpe.mpg.de, A. Ivlev ivlev@mpe.mpg.de)
Available data allow us to construct a model of the density distribution of a filament of dense gas, located in a nearby star-forming region. These data also include measurements of the emission from two different rotational levels of ammonia molecules, which could be used to determine the gas temperature. We are looking for a student to use the model of the gas density, combined with a simple model of the spatial variability of the gas temperature, and compare this to the measured ammonia emission. This work would help us to test a recent theory that young stars act as sources of cosmic rays which may heat the nearby gas.

3. Galaxies and AGN

Project 3.1: 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: 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: 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: 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: 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.

4. Cosmology, large-scale structure, and gravitational lensing

Project 4.1: 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: 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?
Projects in the Physical Cosmology Group (Jochen Weller et al.)

5. Astrophysics and Cosmology with Machine Learning

S. Seitz (stella@usm.lmu.de), T. Varga (vargatn@usm.lmu.de)
We offer at any time various machine learning (ML) Bachelor’s thesis topics, e.g., photometric redshifts with ML, statistical descriptions of clusters of galaxies with ML, detecting rare (e.g., strongly lensed) or ‘weird’ objects with ML. We also offer topics which make use of convolutional neural networks (CNN) in astrophysics and cosmology.

6. Computational and theoretical astrophysics

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

Research in the Computational Astrophysics Group (CAST) ranges from the theoretical investigation of star and planet formation to studies of processes on cosmological scales. A variety of different, well-known numerical codes (such as Ramses, Gadget, Sauron, Gandalf, Mocassin, and others) are used. Primary investigations regard the formation, the structure, and the evolution of protoplanetary disks, the formation of planetary building blocks and planets, the relation between turbulence and phase transitions in the multiphase interstellar medium (ISM), energetic feedback processes, molecular cloud and star formation in galaxies, as well as cosmological structure and galaxy formation and the interplay between feedback processes, AGN, and galaxy evolution and their imprint on the intergalactic medium (IGM) or the intercluster medium (ICM). Thus, our group studies astrophysical processes on length scales covering more than 14 orders of magnitude, from gigaparsec scales of cosmological structures all the way down to sub-AU scales of dust grains within protoplanetary disks.

astrophysical processes on length scales covering more than 14 orders of magnitude

It is now clear that small-scale processes like the condensation of molecular clouds into stars, magnetic fields and the details of heat transport as well as large-scale processes like gas infall from the cosmic web into galaxies and environment are intimately coupled and have to be investigated in a concerted effort. The various past and ongoing projects within the CAST group cover a link between the various scales and contribute to our understanding of crucial aspects of the formation and evolution of stars and protoplanetary disks, central black holes and AGNs, star-forming regions and the ISM, galaxies and their IGM, galaxy clusters and the ICM as well the large-scale structures in the universe. They also also drive the continuous effort to develop and to apply new numerical methods and the next generation of multi-scale codes within the framework of numerical astrophysics.

Past and ongoing Bachelor’s and Master’s thesis projects were always offered with respect to the individual strengths and interests of the students and cover various areas in the field of computational and theoretical astrophysics:

  • Formation of large-scale cosmological structures (dark-matter halos, galaxies, clusters of galaxies, role of black holes, magnetic fields and non-thermal particles)
  • Evolution and structure of the turbulent interstellar medium (ISM physics, self-regulating star formation, formation of molecular clouds, magnetic fields)
  • Physics of galactic centers (active galactic nuclei, origin and nature of the gas cloud G2 near the Galactic center)
  • Formation of planets, stars, and stellar clusters (stars and their influence on the surrounding protoplanetary disc, interstellar matter, radiative transfer, dynamics of particles and planets in protoplanetary disks)
  • Application and development of numerical tools on parallel CPUs and GPUs and visualization (particle-based SPH/N-body, grid-based, moving-mesh or meshless methods)

More detailed information on ongoing and finished projects as well as more detailed information on ongoing research can be found on the web pages of the Computational Astrophysics Group.

Impressum
Datenschutz
Last updated 2021 February 17 15:48 UTC by Webmaster (webmaster@usm.uni-muenchen.de)