KASCADE-Grande Limits on the Isotropic Diffuse Gamma-Ray Flux between 100 TeV and 1 EeV
Abstract
KASCADE and KASCADE-Grande were multi-detector installations to measure individual air showers of cosmic rays at ultra-high energy. Based on data sets measured by KASCADE and KASCADE-Grande, 90% C.L. upper limits to the flux of gamma-rays in the primary cosmic ray flux are determined in an energy range of {10}14{--}{10}18 eV. The analysis is performed by selecting air showers with a low muon content as expected for gamma-ray-induced showers compared to air showers induced by energetic nuclei. The best upper limit of the fraction of gamma-rays to the total cosmic ray flux is obtained at 3.7× {10}15 eV with 1.1× {10}-5. Translated to an absolute gamma-ray flux this sets constraints on some fundamental astrophysical models, such as the distance of sources for at least one of the IceCube neutrino excess models.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2017
- DOI:
- 10.3847/1538-4357/aa8bb7
- arXiv:
- arXiv:1710.02889
- Bibcode:
- 2017ApJ...848....1A
- Keywords:
-
- cosmic rays;
- gamma rays: diffuse background;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- Published in The Astrophysical Journal, Volume 848, Number 1. Posted on: October 5, 2017