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Hamburg Observatory
Hamburg Observatory

Photo: HS/Seelmann

Hamburg Observatory

Radiative transfer simulations

Our research revolves around the theoretical description of atmospheres along with their corresponding radiation fields. In order to compute both with increasing level of detail and resolution, we are developing the PHOENIX code.

Scientists who would like to use our models can download individual ones or full grids either from our local archive or from our collaborators in Göttingen. Those with a worthwhile idea that requires more specialized data should feel free contact us, of course.

High performance computing

Our code has been developed with massive parallelisation on all levels in mind, which can be challenging given the large, looming communication overhead that the radiative transfer problem might bring about if not properly disentangled. PHOENIX has been adapted to benefit from a host of different hardware architectures. It, has proven to run reliably with tens of thousand of parallel tasks and made use of infrastructure such as GPUs, GPGPUs, Intel Xeon Phi (1st and 2nd generation) and more exotic equipment. Depending on available hardware, the code is designed to be easily customized to make the best of available ressources. Parallelisation is mediated via MPI, OpenMP, and OpenCL, depending of the selected configuration. Special attention is devoted to ensure that results are not affected by the choice of hardware or employed compilers.

Head of Group

Prof. Dr. Peter H. Hauschildt
Professor of Astronomy
Hamburger Sternwarte
Gojenbergsweg 112, Room 011, Direktorenvilla
21029 Hamburg
Tel: +49 40 42838 8413
personal website

Available thesis projects

Students interested working with us can expect tasks heavily focused on software engineering, algorithm development, data mining, and systematic comparison between models and observations. Earlier programming experience is recommended as is a knack for delving slightly too deep into the underlying theory.

Currently, we offer the following student research projects:

  • Modelling of irradiated exoplanets. You will apply our code to compute model grids for varied system parameters such as host star type, separation, or irradiation angle in order to study effects on spectra and general observability.
  • Modelling of hot stars involving winds and NLTE effects. You will compute NLTE models of hot stars with and without winds. A follow-up comparison with literature data is critical to appraise the necessity of detailed NLTE model atoms and may contribute to their overall improvement.
  • Sensitivity analysis of NLTE models. You are going to develop and implement a method to predict the dependence of NLTE computations on input data, i.e., the relation between input cross sections and the resulting occupation numbers across the model atmosphere. This work is instrumental for distinguishing which atomic data sets are already sufficiently well constrained for reliable results and which input will require further improvement.
  • There are always additional topics available so feel free to inquire.

Please contact us if you have any questions about our research or if you consider joining us and would like to get to know our work group.