ASTROPHYSICS

An international group of scientists leverages high-performance computing to support current and future measurements of atomic photoionization cross-sections at various synchrotron radiation facilities, ion-atom collision experiments, together with plasma, fusion and astrophysical applications. In their work they solve the Schrödinger or Dirac equation using the R-matrix or R-matrix with pseudo-states approach from first principles. Cross-sections and rates for radiative charge transfer, radiative association, and photodissociation collision processes between atoms and ions of interest for several astrophysical applications are presented.

Modern simulations of galaxy formation, which simultaneously follow the co-evolution of dark matter, cosmic gas, stars, and supermassive black holes, enable us to directly calculate the observable signatures that arise from the complex process of cosmic structure formation. TNG50 is an unprecedented ‘next generation’ cosmological, magneto-hydrodynamical simulation -- the third and final volume of the IllustrisTNG project. It captures spatial scales as small as ~100 parsecs, resolving the interior structure of galaxies, and incorporates a comprehensive model for galaxy formation physics.

Hydrodynamical simulations of galaxy formation have now reached sufficient physical fidelity to allow detailed predictions for their formation and evolution over cosmic time. The aim of this project is to carry out a new generation of structure formation simulations, IllustrisTNG, that reach sufficient volume to make accurate predictions for clustering on cosmologically relevant scales, while at the same time being able to compute detailed galaxy morphologies, the enrichment of diffuse gas with metals, and the amplification of magnetic fields during structure growth.

The large amount of data returned by several space missions to the terrestrial planets has greatly improved our understanding of the similarities and differences between the innermost planets of our Solar System. Nevertheless, their interior remains poorly known since most of the data is related to surface processes. In the absence of direct data of the interior evolution of terrestrial planets, numerical simulations of mantle convection are an important mean to reconstruct the thermal and chemical history of the interior of the Earth, Moon, Mercury, Venus and Mars. In this project, run on Hornet of HLRS, researchers used the mantle convection code Gaia to model the thermal evolution of terrestrial planets and in particular the early stage…

Why do galaxies that live in the enormous structures known as galaxy clusters look different from normal, isolated galaxies, like our Milky Way? To answer this question, astrophysicists have created the Hydrangea simulations, a suite of 24 high-resolution cosmological hydrodynamical simulations of galaxy clusters. Containing over 20,000 cluster galaxies in unprecedented detail and accuracy, these simulations are giving astrophysicists a powerful tool to understand how galaxies have formed and evolved in one of the most extreme environments of our Universe.

Understanding the light emitted by (magnetically) active cool stars (‘M dwarfs’) is a major challenge for astrophysics. In this project, scientists use their PHOENIX/3D code to simulate the light emitted by a ‘box’ inside the outer layers of an active M dwarf in detail. The temperatures and pressures inside the box are taken from an existing gas dynamics simulation (including magnetic field effects) by S. Wedemeyer (Oslo). The computational requirements of detailed non-equilibrium 3D radiative transfer simulations are staggering and require the largest supercomputers on Earth.

Space weather is an increasingly important aspect for our technology-dependent society. Modelling space weather is difficult, however, a Finnish team has succeeded in something that was said to be impossible: an accurate simulation of the large-scale near-Earth space environment. PRACE Tier-0 grant from Hazel Hen (HLRS, Stuttgart) both allowed the Vlasiator team to discover new space physics phenomena, and significantly helped in the acceptance of the second European Research Council grant awarded to the project PI in fall 2015.

Gravitational waves are ripples in spacetime, predicted by Einstein already a century ago. With the announcement earlier this year that gravitational waves had been successfully detected from two black holes merging, attention now turns to other potential sources of gravitational waves. Such sources include dramatic events that may have occurred very early in the history of the universe. Understanding these other sources also informs the design of future gravitational wave detectors, such as the European Space Agency (ESA) project eLISA.

Scientists of the German Aerospace Center Berlin (DLR) exploited the computing capacity of the petascale system Hornet of HLRS to study the convective dynamics and evolution of planetary interiors. The goal of the large-scale simulation project MATHECO (MAntle THErmo-chemical COnvection Simulations), which scaled to 54,000 compute cores of the supercomputer Hornet, was to gain further insights into the cooling history of planets and its influences on volcanic and tectonic surface processes.

Observations show that Earth is constantly bombarded by highly energetic particles that are called cosmic rays. A possible explanation for the origin of the cosmic rays as well as their energy distribution is particle acceleration at shock fronts. Several different physical processes take place there, but due to the large astrophysical distances it is, unfortunately, impossible to study these in-situ. One way out is large scale computer simulations.

The HPC resources of HLRS Stuttgart enabled the world’s first global runs of the near-Earth space using a hybrid-Vlasov approach at highest resolutions. 

Scientists at the Max Planck Institute for Solar System Research in Göttingen employed a three-dimensional numerical model on GCS supercomputer Hermit of HLRS Stuttgart to investigate the heating process of the highly structured and dynamic corona.