Fermi Gamma-ray Space Telescope

Cosmic rays traced by interstellar emission at Fermi-LAT energies and radio frequencies

ELENA ORLANDO
A. Strong, I.V. Moskalenko, S. Digel, G. Johannesson on behalf of the Fermi-LAT collaboration

Abstract:

Cosmic rays propagate in the Milky Way and interact with the interstellar medium and the magnetic field. This produces diffuse emission in gamma rays and radio. Observations of this diffuse emission and comparison with model predictions are powerful tools to understand the distribution and propagation of cosmic rays. However only a multiwavelength approach can remove degeneracies between different models. Our approach is to look at the two energy domains in a joint analysis of gamma-ray and radio data. We present Fermi-LAT Pass 8 data extended to lower energies than previously analyzed, thanks to the improved event reconstruction, and compare them with models and radio-synchrotron observations. Implications for cosmic-ray propagation are discussed.