Laboratoire de Physique Nucléaire et de Haute Énergie

• Main Authors: Pierre Billoir, Antoine Letessier-selvon A
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2000
• Subjects: Medina; North Pole
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.257.9173; http://arxiv.org/pdf/astro-ph/0001427v1.pdf

In this note we argue that the galactic model chosen by E.-J. Ahn, G. Medina-Tanco, P.L. Bierman and T. Stanev in their paper discussing the origin of the highest energy cosmic rays, is alone responsible for the focusing of positive particles towards the North galactic pole. We discuss the validity of this model, in particular in terms of field reversals and radial extensions. We conclude that with such a model one cannot retreive any directional information from the observed direction of the cosmic rays. In particular one cannot identify point sources at least up to energies of about 200 EeV 1. Therefore the apparent clustering of the back-traced highest energy cosmic rays observed to date cannot be interpreted as an evidence for a point source nor for the identification of M87, which happens to be close to the North pole, as being such a source. It was recently claimed [1] that the Ultra High Energy Cosmic Rays (UHECR) observed up to now, may originate from a common source located in the direction of the North pole of our Galaxy; the M87 cluster (Virgo) being the best candidate for such an emitting object. This conclusion was drawn from the result of the backtracing