Impact of Fermi-LAT and AMS-02 results on cosmic-ray astrophysics

This article reviews a few topics relevant to Galactic cosmic-ray astrophysics, focusing on the recent AMS-02 data release and Fermi Large Area Telescope data on the diffuse Galactic gamma-ray emissivity. Calculations are made of the diffuse cosmic-ray induced p + p -> pi(0) -> 2 gamma spectra, normalized to the AMS-02 cosmic-ray proton spectrum at approximate to 10 - 100GV, with and without a hardening in the cosmic-ray proton spectrum at rigidities R greater than or similar to 300GV. A single power-law momentum "shock" spectrum for the local interstellar medium cosmic-ray proton spectrum cannot be ruled out from the gamma-ray emissivity data alone without considering the additional contribution of electron bremsstrahlung. Metallicity corrections are discussed, and a maximal range of nuclear enhancement factors from 1.52 to 1.92 is estimated. Origins of the 300GV cosmic-ray proton and alpha-particle hardening are discussed.