Spectral signatures of PeVatrons

TL;DR

This paper investigates the energy spectra of secondary particles and synchrotron radiation from PeV proton collisions, providing analytical tools to interpret high-energy emissions from cosmic-ray accelerators called PeVatrons.

Contribution

It introduces analytical models for secondary particle spectra in the PeV regime and highlights the distinctive spectral features of synchrotron radiation from secondary electrons.

Findings

Synchrotron radiation spectrum is much shallower than primary protons.

Analytical formulas for secondary spectra in the cut-off region.

Results aid interpretation of high-energy emissions from PeVatrons.

Abstract

We analyze the energy distributions of final (stable) products - gamma rays, neutrinos, and electrons - produced in inelastic proton-proton collisions in the PeV energy regime. We also calculate the energy spectrum of synchrotron radiation from secondary electrons, assuming that these are promptly cooled in the surrounding magnetic field. We show that the synchrotron radiation has an energy distribution much shallower than that of primary protons, and hence we suggest to take advantage of such a feature in the spectral analysis of the highest energy (cut-off) emission region from particle accelerators. For a broad range of energy distributions in the parent protons, we propose simple analytical presentations for the spectra of secondaries in the cut-off region. These results can be used in the interpretation of high-energy radiation from PeVatrons - cosmic-ray factories accelerating protons to energies up to 1 PeV.