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Proposing Institution

Leibniz-Institut für Astrophysik Potsdam (AIP)
Project Manager

Dr. Stefan Gottloeber
An der Sternwarte 1`6
14482 Potsdam
Abstract
According to the standard cosmological paradigm our Universe is made ofunknown Dark Energy (70%), unknown Cold Dark Matter (25%) and mere 5% ofwell known baryons. One of the most demanding challenges to cosmologists isto uncover the nature of Dark Energy and Dark Matter. Sound waves thatpropagate in the early universe imprint a characteristic scale on thedistribution of matter in the Universe. This scale changes with time due tothe expansion of the Universe. The Baryon Oscillation Spectroscopic Survey(BOSS) maps the spatial distribution of Luminous Red Galaxies with very highprecision. These and other upcoming measurements allow to measure thischaracteristic scale at different cosmological times and thus to providedemanding constraints on the cosmic acceleration. These constraints can beused as tests for theories of Dark Energy.In order to interpret the observational data astronomers must compare the datawith theoretical predictions. In the Cosmic Microwave Radiation we observe thestate of the Universe about 13.5 billion years ago. At this time the matterwas almost homogenously distributed with tiny fluctuations in the matterdensity. Due to gravitational instability these fluctuations grow and form theobserved structures in the Universe. The non-linear nature of thegravitational dynamics makes the problem of structure formation intractableanalytically, and therefore the field relies heavily on numerical simulations.The observed galaxies are tiny compared to the observed scales in theuniverse. In order to predict the positions of galaxies with high accuracynumerical simulations of a representative volume of the Universe require veryhigh spatial and mass resolution. This requirement can be achieved with a verylarge number of particles which are used to trace structure formation. Usingmore than 30,000 cores on 4 islands we propose to simulate the formation ofstructure in a box of 19 billion light years side length with 232 billionparticles. With this resolution we will be able to predict the distribution ofmillions of Luminous Red Galaxies on the lighcone on which they areobserved. The construction of such mock catalogs of galaxies under certaintheoretical assumptions and the comparison with the observational data willallow to shed light on the nature of Dark Energy. Simlations as the proposedone hold the key to one of the most fundamental unanswered questions ofcosmology: What is Dark Energy?

Impressum, Conny Wendler