Astroparticle Physics Theory
Very energetic particle are intensively studies in high-energy astrophysics: cosmic rays, neutrinos, gamma rays. Our group is interested in the theoretical description of physical systems in which particle acceleration is known to occur, such as in Supernova Remnants (SNRs), Active Galactic Nuclei (AGN), and Gamma Ray Bursts (GRBs). We use various methods, such as hydrodynamical simulations, kinetic models following the individual particles, and global radiation models. We are also interested in related topics of modern astro-particle physics, such as neutrino physics, dark matter, and cosmology.
The origin of cosmic rays is one of the oldest problems in modern astrophysics. Supernova Remnants (SNRs) have long been thought to be the galactic accelerators of cosmic rays.
We perform hydrodynamical simulations of SNR´s for arbritary ambient media combined with numerical cosmic-ray-acceleration and transport. We are interested in the emission of radiation and the escape of cosmic rays over the entire lifecycle of the SNR.
Microphysics of cosmic plasmas
The processes that determine the energy and spatial distribution of cosmic rays are different from those that shape ordinary gases on Earth, because they rely almost entirely on electric and magnetic fields.
Interesting questions arise:
- Why does nature produce cosmic rays?
- Also, what is the fate of the turbulent magnetic field?
- Do interactions of cosmic rays generate the large-scale magnetic field that permeates the Universe?
The movie shows simulation results for drifting cosmic rays.
The top panel indicates the turbulent magnetic field and the bottom panel depicts the density of interstellar gas. Initially the interstellar gas is at rest and the cosmic rays drift to the left. After a while the structures in both appear to drift as well. In the end there is no relative drift between cosmic rays and interstellar gas, and the growth of magnetic field terminates.