Contribution of Galactic Center–accelerated cosmic rays to the local spectrum at Earth

Ascertain whether the population of cosmic-ray protons and electrons accelerated during the formation of the Fermi Bubbles at the Galactic Center significantly contributes to the cosmic-ray spectrum measured in the solar neighborhood (at Earth).

Background

Leptonic and hadronic models of the Fermi Bubbles imply substantial acceleration of electrons or protons, respectively, during past activity in the Galactic Center. If these cosmic rays diffuse efficiently across the Galactic disk, they could imprint measurable features on the local cosmic-ray spectrum.

Prior analytical work with isotropic diffusion suggested that only a small fraction of the total injected energy might suffice to affect the local spectrum, but realistic anisotropic diffusion along magnetic field lines and uncertain source energetics complicate this assessment. A definitive determination of the local contribution remains a key question for interpreting cosmic-ray measurements near Earth.