Searching for Spurious Solar and Sky Lines in the Fermi-LAT Spectrum

Abstract

We search for a unified instrumental explanation of the spectral features seen near $E_\gamma=130$ GeV in photons collected by Fermi-LAT from the galactic center and from the Earth's limb. We report for the first time a similar feature in photons originating from the vicinity of the Sun, and examine the instrumental characteristics of this Solar feature. To test an instrumental hypothesis, we identify the range of photon incident angles where most of the peak photons are observed in these three spectral features. An examination of the spectrum of photons from the rest of the sky with this characteristic angular range reveals a hint of a spectral feature near $E_\gamma=130$ GeV. These results cast further doubt on the dark-matter-annihilation interpretation of the galactic center peak.