Effects of the galactic magnetic fields on anisotropies in a catalog based research

Cosmic rays (CRs) are charged particles which, throughout their propagation in the Galaxy, undergo the effect of the galactic magnetic field (GMF). Due to these deflections, the arrival directions of CRs do not point in the direction of their sources. The Pierre Auger Observatory observes a hotspot in the Centaurus region which has been correlated with starburst galaxies at significance of 4σ but this result has been obtained assuming that the coherent deflections of the arrival directions of CRs can be neglected.

In this work, we investigate the effect of the GMF deflections on this analysis, by constructing 9 different realizations of the turbulent galactic magnetic field. We created a set of 10.000 simulated data sets for every GMF configurations to witch we apply the analysis reported by the Pierre Auger Collaboration with the intention of recovering compatible scenarios. We show that even in the presence of significance coherent deflections, the reported results can be recovered for a large fraction of realizations. However, when studying the local significance (LiMa) of the brightest and second brightest hotpost, we find agreement in only < 1e−3 of the considered simulations indicating a discrepancy between the data and the model assumptions.