The origin of cosmic ray electrons and positrons

We use direct measurements of electrons and positrons corrected for solar modulation in the force-field approximation to obtain estimations of the local interstellar spectra. The resulting overall electron spectrum fits well with a single power law above a few GeV with spectral index gamma(-) = 3.44 +/- 0.03, consistent with the spectral index obtained for the positron spectrum gamma(+) = 3.43 +/- 0.05, therefore suggesting a common acceleration process for both species. We propose that the acceleration engine was a nearby and recent shock wave originating from the last supernova explosion among those that formed the local bubble. This shock wave had to be quite soft, because no effect is seen on the proton spectrum. However, the large spread between different experiments clearly suggests the need for new, accurate measurements over a large energy range.