Ultra High Energy Particles Propagation and the Transition from Galactic to Extra-Galactic Cosmic Rays

Abstract

We discuss the basic features of the propagation of Ultra High Energy Cosmic Rays in astrophysical backgrounds, comparing two alternative computation schemes to compute the expected fluxes. We also discuss the issue of the transition among galactic and extra-galactic cosmic rays using theoretical results on fluxes to compare different models.

Comments: 6 pages, 6 .eps figures, invited talk given at the 'International Symposium on Future Directions in UHECR Physics', 13-16 February 2012, CERN, Geneva (Switzerland)