Speaker
Nikolas Zimmermann
(Rheinisch-Westfaelische Tech. Hoch. (DE))
Description
Precision measurements by the Alpha Magnetic Spectrometer on the
International Space Station of the primary cosmic-ray electron flux in
the range 0.5 to 700 GeV and the positron flux in the range 0.5 to 500
GeV are presented. The electron flux and the positron flux each require
a description beyond a single power-law spectrum. Both the electron flux
and the positron flux change their behavior at ∼30 GeV but the fluxes
are significantly different in their magnitude and energy dependence.
Between 20 and 200 GeV the positron spectral index is significantly
harder than the electron spectral index. The results show, for the first
time, that neither e+ nor e− can be described by a single power law
above 27.2 and 52.3 GeV, respectively. The determination of the
differing behavior of the spectral indices versus energy is a new
observation and provides important information on the origins of
cosmic-ray electrons and positrons.
Primary author
Nikolas Zimmermann
(Rheinisch-Westfaelische Tech. Hoch. (DE))
