Diffuse Galactic Gamma Rays from Shock-Accelerated Cosmic Rays
Abstract
A shock-accelerated particle flux \propto p^-s, where p is the particle momentum, follows from simple theoretical considerations of cosmic-ray acceleration at nonrelativistic shocks followed by rigidity-dependent escape into the Galactic halo. A flux of shock-accelerated cosmic-ray protons with s ~ 2.8 provides an adequate fit to the Fermi-LAT gamma-ray emission spectra of high-latitude and molecular cloud gas when uncertainties in nuclear production models are considered. A break in the spectrum of cosmic-ray protons claimed by Neronov, Semikoz, & Taylor (PRL, 108, 051105, 2012) when fitting the gamma-ray spectra of high-latitude molecular clouds is a consequence of using a cosmic-ray proton flux described by a power law in kinetic energy.
Cite
@article{arxiv.1206.2899,
title = {Diffuse Galactic Gamma Rays from Shock-Accelerated Cosmic Rays},
author = {Charles D. Dermer},
journal= {arXiv preprint arXiv:1206.2899},
year = {2015}
}
Comments
Version to correspond to published letter in PRL; corrected Fig. 2