http://arxiv.org/abs/1806.04194
The luminosity densities of high-energy cosmic radiations are studied to find connections among the various components, including high-energy neutrinos measured with IceCube and gamma rays with the Fermi satellite. Matching the cosmic-ray energy generation rate density in a GeV-TeV range estimated for Milky Way with the ultrahigh-energy component requires a power-law index of the spectrum, $s_{\rm cr}\approx2.1-2.2$, somewhat harder than $s_{\rm cr}\approx2.3-2.4$ derived from the AMS-02 experiment, pointing towards either reacceleration of galactic cosmic rays or presence of extragalactic sources with $s_{\rm cr}\sim2$. The soft GeV-TeV cosmic-ray spectrum extrapolated to higher energies can be compatible with PeV cosmic rays inferred from neutrino measurements, but overshoots the CR luminosity density to explain GeV-TeV gamma rays. The extrapolation from ultrahigh energies with a hard spectrum, on the other hand, can be consistent with both neutrinos and gamma-rays. We discuss possible cosmic-ray sources that can be added.
K. Murase and M. Fukugita
Wed, 13 Jun 18
54/57
Comments: 12 pages, 3 figures, 2 tables
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