Max Planck Institute for Radio Astronomy/Argelander Institute for Astronomy Main Colloquium
Titel: Cosmic-Ray PeVatrons: Extreme Particle Accelerators in the Milky Way
Speaker: Prof. Dr. Felix Aharonian, DIAS/Dublin and MPIK/Heidelberg
PeVatrons – cosmic-ray factories capable of accelerating particles to petaelectronvolt (PeV) energies – are widely believed to play a key role in resolving the century-old mystery of the origin of Galactic cosmic rays. For decades, the nature of these objects has been the subject of extensive theoretical and observational studies, with supernova remnants long regarded as the prime candidates. In recent years, major observational advances, primarily the detection of gamma rays with energies exceeding 100 TeV from dozens of Galactic sources, have led to a breakthrough with far-reaching implications. Taken together, these developments suggest that the Milky Way hosts a diverse population of extreme particle accelerators capable of producing cosmic rays at PeV energies. At the same time, increasingly precise measurements of cosmic-ray spectra and composition have significantly improved our understanding of Galactic cosmic rays from GeV to PeV energies. These observations reveal that a diversity of cosmic-ray accelerators associated with several Galactic source populations, including supernova remnants, star-forming regions, pulsar wind nebulae, and microquasars, may create, despite their fundamentally different physical environments, near-ideal conditions for particle acceleration operating close to the theoretical limits. This review summarizes the theoretical predictions, observational discoveries, and current interpretations of PeVatrons, discusses their implications for high-energy astrophysics, particularly for the origin of Galactic cosmic rays, and outlines future directions for multiwavelength observations.