What does the small anisotropy in cosmic-ray arrival directions mean?

At multi-TeV energies, researchers have reported a small anisotropy in the arrival directions of cosmic rays, amounting to a few tenths of a percent. Currently, the scientific community does not understand the cause of this phenomenon.1

While cosmic rays are generally studied to determine their origins, pinpointing precise sources is difficult because intergalactic and galactic magnetic fields deflect most charged particles during their transit. Because this specific anisotropy remains unexplained, it does not yet provide a clear indication of the particles' origins or the physical processes governing their distribution.1