Arrival Directions of Ultrahigh-Energy Cosmic Rays

Abstract

We discuss some important properties of the arrival directions of ultrahigh-energy cosmic rays detected by the Telescope Array and the Pierre Auger experiments using data released by both collaborations. We also discuss the potential sources and analyse the effect of correcting the arrival directions to take into account the deflections of the cosmic rays by the magnetic field of our galaxy for one specific model of the galactic magnetic field under several assumptions about the composition of the primary cosmic rays. The results show that for a proton-dominated composition the maxima deflections, due to the galactic magnetic field model considered in this paper, are about 20° for energies higher the 60 EeV, allowing the approximation of doing astronomy with charged particles, while for medium and heavy compositions the galactic magnetic deflections are much higher and cannot be excluded from any search of the sources of ultrahigh-energy cosmic rays. We also study the validity of the backpropagation method by means of forward propagation of the particles from potential astrophysical sources to the vicinity of the Earth.