Cosmic rays from the galactic centre

An old model for the origin of cosmic rays is reinvestigated. It is shown that under the assumption of repeated explosions in the galactic centre separated in time by 107 yr, the last one being 106 yr ago, a number of observed cosmic-ray properties can be reproduced. Acceptable fits appear for the form of the energy spectrum of protons from 1-108 GeV and the mean grammage. The long-term near-constancy of the intensity is understandable. However, the observed anisotropy and the grammage distribution can be accounted for only if the diffusion in the disc is much smaller than that in the halo. (author)