Speaker
Dario Grasso
Description
The Fermi Large Area Telescope (LAT) has recently provided the measurement of the high energy (20 GeV to 1 TeV) cosmic ray electrons plus positrons (CRE) spectrum with unprecedented accuracy. The spectrum shows no prominent features and it is significantly harder than that inferred from several previous experiments. While the reported Fermi-LAT data alone can be interpreted in terms of a single (electron dominated) Galactic component, when combined with other complementary experimental results, specifically the CRE spectrum measured by H.E.S.S., and especially the positron fraction measured by PAMELA, an additional electron and positron component has to be invoked. We will show that electron-positron pairs acceleration in Galactic pulsars offer a natural interpretation of all these results and briefly mention other viable scenarios including secondary electron and positron production in supernova remnants and dark matter annihilation/decay. We also briefly discuss the possibility of discriminating among those interpretations by means of other independent measurements.
