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The Fermi-LAT data revealed giant bubbles of emission above and below theGalactic plane with an energy spectrum significantly harder than seen fromother directions. How the bubbles connect to the Galactic plane is unclear. Wefind that bubble-like emission is not only found in the halo, but it isstrongly present in the Galactic plane as well with a morphology close to thespatial distribution of the 1.8 MeV gamma-ray line from 26Al, a radioactivenucleus synthesized in SNRs. In addition, the spectral shape of this hardcomponent coincides with the predicted spectrum from cosmic rays trapped insources. Hence, we propose that the bubble-like emission in the plane has ahadronic origin, which arises from SCRs. The bubbles in the halo have the sameenergy spectrum, which suggests that they are outflows from the plane with thegamma-rays arising from hadronic interactions of protons trapped in a plasma ofadvected gas. Towards the Galactic center (GC) we observe the 1-3 GeV excess,but observe this excess in addition in all regions where there is strong 26Alproduction. This excludes the dark matter annihilation interpretation. Instead,we propose that the excess is caused by a deficit of the CRs at low rigiditiesin the regions of dense molecular clouds, which are characterized by higherenergy losses and stronger stellar winds. The 26Al line is a tracer of suchregions. If we introduce a break in the cosmic ray injection spectra in theregions of strong 26Al production to effectively take the deficit of lowrigidity CRs into account, the excess in the Galactic plane and towards the GCboth disappear. We thus conclude that the excess in the Galactic center islargely an artefact from the excess in the Galactic plane. The correlationbetween the two originates simply from the lines-of-sight towards the GCcrossing the Galactic plane.

Evidence for a hadronic origin of the Fermi Bubbles and the Galactic Excess