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Main Colloquium |
Prof. Dr. Felix Aharonian
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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.