The energy spectrum observed by the AGASA experiment and the spatial distribution of the sources of ultra-high-energy cosmic rays

Seven and a half years of continuous monitoring of giant dr showers trigger ed by ultra-high-energy cosmic rays have been summarized recently by the AG ASA collaboration. The resulting energy spectrum indicates clearly that the cosmic-ray spectrum extends well beyond the Greisen-Zatsepin-Kuzmin (GZK) cutoff at similar to 5 x 10(19) eV. Furthermore, despite the small-number s tatistics involved, some structure in the spectrum may be emerging. Using n umerical simulations, it is demonstrated in the present work that these fea tures are consistent with a spatial distribution of sources that follows th e distribution of luminous matter in the local universe. Therefore, from th is point of view, there is no need for a. second high-energy component of c osmic rays dominating the spectrum beyond the GZK cutoff.