Sensitivity of orbiting JEM-EUSO to large-scale cosmic-ray anisotropies
  The two main advantages of space-based observation of extreme-energy ($\gtrsim 10^{19}$~eV) cosmic-rays (EECRs) over ground-based observatories are the increased field of view, and the all-sky coverage with nearly uniform systematics of an orbiting observatory. The former guarantees increased statistics, whereas the latter enables a partitioning of the sky into spherical harmonics. We have begun an investigation, using the spherical harmonic technique, of the reach of \J\ into potential anisotropies in the extreme-energy cosmic-ray sky-map. The technique is explained here, and simulations are presented. The discovery of anisotropies would help to identify the long-sought origin of EECRs. 
Peter B. Denton, Luis A. Anchordoqui, Andreas A. Berlind, Matthew   Richardson, Thomas J. Weiler (for the JEM-EUSO Collabora...
astro-ph.IM astro-ph.HE