What celestial events are responsible for accelerating Galactic Cosmic Rays (GCRs) to near light speed?

Answer

Distant, violent astrophysical events, such as supernovae

GCRs are atomic nuclei accelerated to extremely high kinetic energies primarily by powerful, distant astrophysical events like supernovae.

What celestial events are responsible for accelerating Galactic Cosmic Rays (GCRs) to near light speed?
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