Energetics of high-energy cosmic radiations

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 ultra-high-energy component requires a power-law index of the spectrum ${s}_{\mathrm{cr}}\ensuremath{\approx}2.1--2.2$, somewhat harder than ${s}_{\mathrm{cr}}\ensuremath{\approx}2.3--2.4$ for the local index derived from the AMS-02 experiment. 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. These point towards either reacceleration of galactic cosmic rays or the presence of extragalactic sources with a hard spectrum. We discuss possible cosmic-ray sources that can be added.