DO WE SEE THE ‘IRON PEAK’?

Anatoly D Erlykin,Arnold W Wolfendale

doi:10.14311/ap.2013.53.0723

Abstract

Recent measurements of the cosmic ray (CR) energy spectrum in the PeV region and above have confirmed the remarkable sharpness of the knee and revealed another structure at about 70PeV which we call the ‘Iron Peak’. The position and the shape of this structure lead us to associate its likely origin with the same single source responsible for the the knee. We have analysed the shape of the single source spectrum and concluded that its mass composition is rather similar to that for the bulk of CR in the TeV ÷ PeV region. Since it is generally accepted that these CR originate mainly in supernova explosions, this gives an additional argument in favour of our single source being a supernova remnant.

Highlights

The origin of cosmic rays (CR) is usually studied by analysing the general shape of the energy spectrum, mass composition and anisotropy
If the production of CR by these sources has an explosive character as from supernovae (SN) and subsequent remnants (SNR), their random explosions make the non-uniformity of the CR space-time distribution even stronger
Since the energy spectra of all 5 mass groups in CR from the single source have essentially a non-power law shape ‘on arrival’, it is unreasonable to describe the mass composition in terms of the relative fractions of their flux at a fixed energy per particle

Summary

Introduction

The origin of cosmic rays (CR) is usually studied by analysing the general shape of the energy spectrum, mass composition and anisotropy. We would like to say that additional information can be obtained from the study of the detailed shape or the ‘fine structure’ of the CR energy spectrum. If the production of CR by these sources has an explosive character as from supernovae (SN) and subsequent remnants (SNR), their random explosions make the non-uniformity of the CR space-time distribution even stronger. This has to result in the appearance of a fine structure in the CR spectrum at some level

Evidence for a fine structure in the knee region

Origin of the fine structure

Discussion

Findings

Conclusion