A new Monte Carlo Generator of Ultra High Energy Cosmic Rays from the Local and Distant Universe

Abstract

For the understanding of the origin and propagation of ultra-high energy cosmic rays (UHECR) we developed a new approach to simulating UHECRs from an arbitrary number of sources based on Monte Carlo technique. The method consists of a combination of three steps. For distant sources we apply commonly accepted parameterizations to calculate the contribution to the observed cosmic ray flux. For sources of the local universe we use forward tracking through realistic matter distributions and magnetic fields resulting from explicit simulations of large-scale structure formation. From the calculations and the forward tracking we generate maps of the probability to observe a particle with a given energy from a discrete direction. To account for deflections in the galactic field, these lenses are transformed by matrices calculated from backtracking of antiparticles through field parameterizations. Based on these probability maps, Monte Carlo production of individual UHECR data is performed which will then be compared to the physics analyses of UHECR measurements. This simulated UHECR data will serve for optimizing the analysis techniques used in UHECR measurements as well as constraining the parameter space of the underlying source and magnetic field models.