Fermi Bubbles and Bubble-like emission from the Galactic Plane
  The diffuse gamma-ray sky revealed 'Bubbles' of emission above and below the
Galactic Plane symmetric around the centre of the Milky Way with a height of 10
kpc in both directions. At present there is no convincing explanation for the
origin. To understand the role of the Galactic Centre (GC) one has to study the
Bubble spectrum inside the disc, a region which has been excluded from previous
analysis because of the large foreground. From a novel template fit, which
allows a simultaneous determination of the signal and foreground in any
direction, we find that bubble-like emission is not only found in the halo, but
in the Galactic Plane as well with a width in latitude coinciding with the
molecular clouds. The longitude distribution has a width corresponding to the
Galactic Bar with an additional contribution from the Scutum-Centaurus arm. The
energy spectrum of the Bubbles coincides with the predicted contribution from
CRs trapped in sources (SCRs). Also the energetics fits well. Hence, we
conclude that the bubble-like emission has a hadronic origin, which arises from
SCRs and the Bubbles in the halo arise from hadronic interactions in advected
gas. Evidence for advection is provided by the ROSAT X-rays from hot gas in the
Bubble region.
