The arrival direction distribution of Extremely High Energy cosmic rays observed by AGASA

摘要

Study of the arrival direction distribution plays a key role in finding sources of the Extremely High Energy Cosmic Rays (EHECR).Greisen-Zatsepin-Kuz'min (GZK) mechanism [1,2] limits the propagation of EHE cosmic rays significantly and only nearby sources can contribute to the local EHECR flux[3-6].Furthermore EHECRs travel intergalactic spaces almost linearly.Hence,we expect they can be traced back to their sources.Here we report a small-sacle anisotropy of the arrival direction distribution of EHECRs observed by AGASA above 10~(19)eV.This result strongly suggests the existence of point sources of EHECRs.