Fermi Gamma-ray Space Telescope

The Interstellar Cosmic Ray Spectrum from Multifrequency Observations of the Interstellar Emission

Elena Orlando


Interactions of cosmic rays with the interstellar medium and magnetic field produce diffuse emissions that span the electromagnetic spectrum from radio to gamma rays. Observations of this diffuse emission are an invaluable tool for understanding densities and spectra of CRs in different places of our Galaxy. We present interstellar CR spectra and their properties derived by combining multi-frequency observations of the interstellar emission from radio to gamma rays, latest direct CR measurements from Voyager 1 and AMS02, and CR propagation models in a self-consistent way. Results are based on Orlando 2018, MNRAS 475, 2724.