Over recent years, impressive progress has been achieved in the precision and quality of Cosmic Ray (CR) measurements. It includes the detection of a substantial hardening of the energy spectrum of protons and nuclei above 100 GeV/amu; the extension of the electron spectrum to the energy of 20 TeV, the discovery of anomalously high content of secondary positrons and antiprotons, etc. I will discuss the implications of these results in the context of the current paradigm of Galactic CRs, in particular in relation to the potential CR factories revealed by the high and very-high energy gamma-ray observations. I will argue that supernova remnants remain the prime candidates as major sources of galactic cosmic rays, but, presumably, with a reduced role at highest energies. I will discuss the clusters of young massive stars and the supermassive black hole in the Galactic Center as alternative suppliers of PeV particles to galactic cosmic rays.
About the speaker
Felix Aharonian's research group in MPIK Heidelberg covers several areas of Astrophysics and Astroparticle Physics:
- origin of Galactic Cosmic Rays, in particular in the context of particle acceleration in shell type supernova remnants, pulsar wind nebulae, X-ray binary systems;
- nonthermal processes in the Galactic Center;
- processes of acceleration and radiation of electrons and protons in relativistic outflows - in pulsar winds, in microquasars, in small and large scale jets of active galactic nuclei, in GRBs;
- gamma-ray and neutrino production mechanisms in different astrophysical environments;
- links between high energy gamma-ray astronomy and neutrino astronomy;
- theoretical aspects of the imaging atmospheric cherenkov technique;
- physics of compact relativistic objects;
- prompt optical afterglows of gamma-ray bursts.
Although these studies have rather general character and are not limited by specific objects, astrophysical scenarios, radiation processes, energy bands, etc., generally they are conducted in the context of high energy gamma-ray phenomena recently revealed, in particular by HESS, in different galactic and extragalactic source populations.
The group has a status of the second official group representing MPIK in the HESS collaboration. Therefore, a substantial fraction of the work of our group is conducted within the framework of the HESS experiment, especially in the context of interpretation of very high energy gamma-ray observations.
More details on Felix's research group can be found here.