IAP(Institut d'astrophysique de Paris) and Ecole Polytechnique
98bis Boulevard Arago
SF2A- PNC- PCHE-
75014
Paris, France
Presentation 1 : Poster
The Ultra High Energies Cosmic Rays above 4*10^19 eV. (PCHE)
Isola C., Sigl G., Lemoine M.
Despite a growing amount of data the origin of cosmic rays especially
at the highest energies is still obscure. For ultra-high energy cosmic
rays (UHECRs) with energies above 10^18 eV there are still many
open questions concerning the acceleration mechanism, the chemical
composition of the primary particles and their sources.
In the bottom-up scenario the UHECR are assumed to be protons accelerated in powerful astrophysical sources.
We present numerical simulation for energy spectra, angular
distribution and auto-correlation function for nucleons above
4*10^19 eV propagating in extra-galactic magnetic fields in the
sub-micro Gauss range.
We show that the a model which just one single source is not consistent with the recent observational data from AGASA, which give isotropy at large scales and clustering at small scales. On the other hand a distribution of about ten sources in the Local Superclusters with strong magnetic fields ~0.3 micro Gauss seems to reproduce quite well the observed small scale clustering.