Klein–Nishina Effect and the Cosmic Ray Electron Spectrum

Radiative energy losses are very important in regulating the cosmic ray electron and/or positron (CRE) spectrum during their propagation Milky Way. Particularly, Klein–Nishina (KN) effect of inverse Compton scattering (ICS) results less efficient high-energy electrons, which is expected to leave imprints on propagated spectrum. It has been proposed that hardening CRE spectra around 50 GeV observed by Fermi-LAT, AMS-02, and DAMPE could be due KN effect. We show this work transition from Thomson regime ICS actually quite smooth compared with approximate treatment adopted some previous works. As a result, spectral CREs cannot explained means an additional primary electrons needed. also provide parameterized form for accurate calculation energy-loss rate wide range.