Pulsars do not produce sharp features in the cosmic-ray electron and positron spectra
Isabelle John, Tim Linden
Abstract
Pulsars are considered to be the leading explanation for the excess in cosmic-ray positrons. A notable feature of standard pulsar models is the sharp spectral cutoff produced by the increasingly efficient cooling of very-high-energy electrons by synchrotron and inverse-Compton processes. This spectral break has been used to argue that many pulsars contribute to the positron flux and that spectral features cannot distinguish between dark matter and pulsar models. We prove that this feature does not exist---it appears due to approximations that treat inverse-Compton scattering as a continuous, instead of as a discrete and catastrophic, energy-loss process. Astrophysical sources do not produce sharp spectral features via cooling, reopening the possibility that such a feature would provide evidence for dark matter.