A single source of cosmic rays in the range 10(15)-10(16) eV

The advent of new and improved extensive air shower (EAS) arrays-and the attendant generation of data of higher statistical precision than hitherto-has led us to return to an old problem: the origin of the change in spectral slope at an energy of 3 x 10(15) eV. The data recorded are the so-called shower size spectra at ground level, i.e. the spectrum of the total number of cosmic rays inferred for each shower, and we use results from seven arrays which are situated at levels ranging from near sea level to half way up the atmosphere (in terms of atmospheric mass per unit area). The method adopted by us is a new one which enables the combination of experimental data in such a way that previously unrecognized features are now apparent. We present evidence for a spectral shape of the shower size spectrum, and thus the primary particle energy spectrum, which has the signature of an extra component from a single source which protrudes above the 'background' due to many other cosmic ray sources in the Galaxy. It is proposed that the 'single source' is a local supernova remnant.