First results on Cosmic Ray electron spectrum below 20 GeV from the Fermi LAT

TL;DR

This paper presents initial measurements of the cosmic ray electron spectrum below 20 GeV using the Fermi LAT, highlighting the instrument's capability to distinguish electron signals and analyze local effects like solar modulation.

Contribution

First measurement of the cosmic ray electron spectrum below 20 GeV using Fermi LAT, demonstrating its effectiveness in electron detection and analysis of local magnetic effects.

Findings

Electron spectrum measured below 20 GeV

Observation of local magnetic field effects on electrons

Validation of event selection and analysis methods

Abstract

Designed to be a successor of the previous flown space based gamma ray detectors, the Fermi Large Area Telescope (LAT) is also an electron detector. Taking advantage of its capability to separate electromagnetic and hadronic signals it is possible to accurately measure the Cosmic Ray electron spectrum. The spectra of primary cosmic ray electrons below 20 GeV is influenced by many local effects such as solar modulation and the geomagnetic cutoff. For energies below a few GeV it is possible to observe the albedo population of electrons which are controlled by the local magnetic field. In this paper we present the LAT electron analysis in particular event selection and validation as well as the first results on the measurement of the electron spectrum below 20 GeV.