Investigation of Cosmic-Ray Sources with Gamma-Ray Initiated Showers

TL;DR

This paper proposes a novel method to investigate ultra-high energy cosmic ray sources by analyzing gamma-ray initiated air showers, which depend on source distance and energy spectra, enabling source characterization.

Contribution

The paper introduces a new approach using gamma-ray emission analysis in extragalactic space to study cosmic ray sources, focusing on gamma-ray initiated air showers.

Findings

Gamma-ray emission intensity depends on source distance and energy spectra.

Number of gamma-ray initiated showers varies significantly with source parameters.

Method can distinguish source characteristics with current shower detection statistics.

Abstract

A new method of investigating ultra-high energy cosmic ray sources is suggested. The method is based on analysis of gamma-ray emission that is generated in extragalactic space when ultra-high energy cosmic particles interact with cosmic background. We have found that intensity of the gamma-ray emission depends on characteristics of cosmic ray sources, specifically on their remoteness and initial particle energy spectra. In the Earth atmosphere cosmic rays initiate air showers, therefore selecting quanta-initiated showers (and excluding those from the galactic plane, gamma-ray sources, etc.) we can obtain above mentioned source characteristics. We derive that the number of quanta-initiated showers is 0 or ~3x1000 depending on source parameters, typical statistics of showers registered at 10^14 eV being of ~10^8. The difference is large enough to use this method for studying ultra-high energy cosmic ray sources.