A new measurement of cosmic-ray electrons and 2 positrons with the Large Area Telescope
2017 August 16
We present an updated measurement of the cosmic-ray electron and positron spectrum between 7~GeV and 2~TeV, based on 7 years of data collected with the Fermi Large Area Telescope (LAT). The LAT is the first space-based instrument to directly explore the region above 1~TeV. At such high energies, the shape of the spectrum can provide useful information about the origin and propagation of cosmic-ray electrons in the nearby Galactic space. The spectrum that we measure suggests the presence of a break at 50 GeV. Above 50 GeV, the spectrum is well described by a single power law with a spectral index of 3.07 ± 0.02 (stat+syst) ± 0.04 (energy measurement). An exponential cutoff lower than 1.8 TeV is excluded at 95% CL.