Evidence of an anisotropy in the arrival direction of cosmic rays with energies above 1019eV

Abstract

Evidence is presented that the arrival direction distribution of cosmic rays with energies above 1019 eV is not isotropic. Harmonic analyses indicate that there is, prima facie, a first harmonic (amplitude=44%, chance probability=2.6%, phase (in right ascension)=13.3+or-1.5 h) at declinations above 0 degrees , and that there is a significant second harmonic (amplitude=101%, chance probability=0.2%, phase 7.8, 19.8+or-1 h) at declinations below -30 degrees . Supporting evidence from low energy data is also discussed.