Research

Since more than 100 years, the origin of the charged cosmic ray particles is one of the unsolved problems of physics. These particles can have energies millions of times higher than what is reachable at the large accelerators at CERN. Due to deflection of these particles by omnipresent magnetic fields, it is not possible to trace them back to their origin(s). Therefore, very-high energy photons are used as tracers. Several dedicated telescopes have been built in the past, and construction of the next generation has started. While the origin(s) of the cosmic ray particles is still not resolved, the unexpected richness of galactic and extragalactic sources of very-high energy photons has started the new research field of Very-high Energy Astronomy.

In addition, the investigation of very-high energy photons can be used to learn about fundamental physics questions like Cold Dark Matter and Quantum Gravity, as well as investigate the density of extragalactic infrared light and magnetic fields that are important for cosmology.

The group is currently involved in three experiments: external page MAGIC, external page FACT and external page CTA . These all are dedicated (arrays of) telescopes to catch dim, short flares of Cherenkov light that are emitted when a very-high energy (VHE, E>100GeV) cosmic-ray particle or gamma-ray  interacts with the atmosphere. This allows to investigate the most energetic objects in the universe.