Measurement of the Cosmic Ray electron plus positron spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope

Understand

Designed as a high-sensitivity gamma-ray observatory, the Fermi Large Area Telescope is also an electron detector with a large acceptance exceeding 2 sq-mt sr at 300 GeV.

• Building on the gamma-ray analysis, we have developed an efficient electron detection strategy which provides sufficient background rejection for measurement of the steeply-falling electron spectrum up to 1 TeV.
• Our high precision data show that the electron spectrum falls with energy as E^(-3.0) and does not exhibit prominent spectral features