Analysis of CALET Data for Anisotropy in Electron+Positron Cosmic Rays

Abstract

The ISS-based Calorimetric Electron Telescope (CALET) is directly measuring the energy spectrum and direction distribution of electron+positron cosmic-rays up to 20 TeV. A main goal of CALET is to identify a signature of a nearby supernova remnant in electron+positron cosmic-rays, such as a spectral feature in the TeV region and/or a detectable anisotropy. The electron+positron events measured by CALET have been analyzed for a possible dipole anisotropy, as well as higher multipole moments. The methods for deriving limits on the anisotropy from the reconstructed events, as well as the procedures to compensate for the non-uniform exposure to the sky and inhomogeneous acceptance of the detector are explained. Preliminary results for the measured anisotropy and upper limits depending on threshold energy are presented, together with sensitivity estimations and a comparison to the expected anisotropy caused by the Vela supernova remnant.