Large Scale Magnetic Fields and the Number of Cosmic Ray Sources above 10^(19) eV

Abstract

We present numerical simulations for the two-point correlation function and the angular power spectrum of nucleons above 10^{19} injected by a discrete distribution of sources following a simple approximation to the profile of the Local Supercluster. We develop a method to constrain the number of sources necessary to reproduce the observed sky distribution of ultra-high energy cosmic rays, as a function of the strength of the large scale cosmic magnetic fields in the Local Supercluster. While for fields B < 0.05 micro Gauss the Supercluster source distribution is inconsistent with the data for any number of sources, fields of strength B~0.3 micro Gauss could reproduce the observed data with a number of sources around 10.