Magnetic deflections and possible sources of clustered ultra-high-energy cosmic rays

Corrections for the deflection of charged cosmic-ray particles by the regular component of the Galactic magnetic field (GMF) destroy the ultra-high-energy cosmic-ray clusters observed by the AGASA and Yakutsk experiments, as well as the cluster of five cosmic rays observed by the AGASA, HiRes and Yakutsk experiments, for any of conventional GMF models. This may mean that either the clusters are accidental, or the clustered cosmic rays have neutral primaries, or the GMF models do not work. Assuming the latter possibility, we study the fiveplet in more detail and find which deflections would not destroy the cluster and possibly make it tighter. For different primary charges, we discuss possible astrophysical sources of the particles forming the fiveplet. (c) 2006 Elsevier B.V. All rights reserved.