Excellent Universe PhD Theses 2015

The PhD Awards 2015 of the Excellence Cluster Universe go to the experimental work of Peter Ludwig (TUM) and the theoretical thesis of Cora Uhlemann (LMU).

The doctoral thesis work of Peter Ludwig is the experimental discovery of supernova-produced F-60 within biologically produced nano-scale magnetite (Fe₃O₄) crystals. This discovery was achieved using accelerator mass spectrometry (AMS) at the Maier Leibnitz tandem Laboratory (MLL). The bacteria build up an intracellular chain of these crystals, which is called a “magnetosome”. The magnetite crystals are intracellularly made by so-called magnetotactic bacteria, which live in ocean sediments. After cell death, these magnetite crystals remain embedded within the sediment over geological time scales and are then referred to as “magnetofossils”. The magnetotactic bacteria themselves extract the iron from microscopic iron-bearing dust particles, which rain down into the oceans as part of the Earth’s iron-cycle. For the first time ever, Peter Ludwig was able to achieve a time resolved Fe-60 signal of supernova ejecta transiting our solar system circa 2 Million years ago, with a duration of about 750,000 years. One of Peter Peter Ludwig’s additional achievements is a new sensitivity limit for Fe-60, which is more than a factor of ten better than any previous AMS works.

The theoretical work of Cora Uhlemann "Theoretical models for the formation of the Large-Scale Structure in the Universe" deals with the theoretical description of structure formation in dark matter. It is dedicated to two essential aspects: The formation of single bound structures of dark matter and the formation of large-scale structure of the universe. Both are theoretically not fully understood so that numerical simulations are necessary. The first part of the thesis is dedicated to improving the theoretical description and to deepening the understanding of the results that were obtained in numerical simulations. Then, Cora Uhlemann introduces the Schrödinger method and shows that this method is complementary to the currently used N-particle simulations. The second part of the thesis gains improved theoretical predictions with relevance for the analysis of modern galaxy surveys that allow to explain observations derived from them and to extract further cosmological information.

The Universe PhD Award is endowed with 2000 Euro for each awardee.