Propagation of UHE cosmic rays in a structured universe

Abstract

In a gravitationally unstable universe, the structure of dark matter and galaxies, intergalactic gas and magnetic field can have severe impact on the propagation of ultra high energy cosmic rays (UHECR) (Ryu & Kang, this proceedings). The possible effects include spatial confinement and directional focusing along the supergalactic matter sheets, as well as universal re-acceleration at large scale shock fronts, and spectral modification due to energy dependent leakage into cosmic voids. As a result, the GZK-cutoff may be less pronounced and occur at a higher energy, where the stochastic nature of both acceleration and energy loss processes has to be taken into account.

Contributed Paper to the 18th Texas Symposium on Rel. Astrophysics and Cosmology, Chicago 1996. 3 Pages, no figures