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تسجيل مستخدم جديدParticle acceleration and the origin of gamma-ray emission from Fermi Bubbles
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Fermi LAT has discovered two extended gamma-ray bubbles above and below the galactic plane. We propose that their origin is due to the energy release in the Galactic center (GC) as a result of quasi-periodic star accretion onto the central black hole. Shocks generated by these processes propagate into the Galactic halo and accelerate particles there. We show that electrons accelerated up to ~10 TeV may be responsible for the observed gamma-ray emission of the bubbles as a result of inverse Compton (IC) scattering on the relic photons. We also suggest that the Bubble could generate the flux of CR protons at energies > 10^15 eV because the shocks in the Bubble have much larger length scales and longer lifetimes in comparison with those in SNRs. This may explain the the CR spectrum above the knee.
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We analyse processes of particle acceleration in the Fermi Bubbles. The goal of our investigations is to obtain restrictions for acceleration mechanisms. Our analysis of the three processes: acceleration from background plasma, re-acceleration of rel
ativistic electrons emitted by supernova remnants, and acceleration by shocks generated by processes of star tidal disruption in the Galactic Center, showed that the model of multi-shock acceleration does not have serious objections at present and therefore seems us more attractive than others.
The Fermi Bubbles are enigmatic gamma-ray features of the Galactic bulge. Both putative activity (within $sim$ few $times$ Myr) connected to the Galactic center super-massive black hole and, alternatively, nuclear star formation have been claimed as
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