Full-sky search for ultrahigh energy cosmic ray anisotropies

Using data from the Sydney University Giant Air-Shower Recorder and the Akeno Giant Air-Shower Array experiments taken during a 10 yr period with nearly uniform exposure to the entire sky, we search for large-scale anisotropy patterns in the arrival directions of cosmic rays with energies >10^19.6eV. We determine the angular power spectrum from an expansion in spherical harmonics for modes out to l=5. Based on available statistics, we find no significant deviation from isotropy. We compare the rather modest results which can be extracted from existing data samples with the results that should be forthcoming as new full-sky observatories begin operation.