http://arxiv.org/abs/1402.4558
A high-energy component in the radio galaxy Centaurus A was reported after analyzing four years of Fermi Large Area Telescope data. The spectrum of this component is described by means of a broken power law with a break energy of 4 GeV and, below and above spectral indexes of $\alpha_1$=2.74$\pm$0.03 and $\alpha_2$=2.09$\pm$0.20, respectively. In addition to this component, its spectral energy distribution shows two prominent humps, a low-energy hump, at an energy of 10$^{-2}$ eV, and a high-energy hump, at about 150 keV and also a faint $\gamma$-ray flux at TeV energies reported by H.E.S.S. Moreover, Pierre Auger Observatory reported some ultra-high-energy cosmic rays, and a non TeV – PeV neutrino detection was reported by IceCube in this direction. In this paper we analyze the $\gamma$-ray spectrum at the GeV – TeV energy range. We show that the new Fermi data can be described as a superposition of synchrotron self-Compton emission, muon synchrotron radiation and $\pi^0$ decay products. Muons and $\pi^0$s are generated in the interactions of accelerated protons in the jet with two populations of seed photons which were reported by Compton Gamma-Ray Observatory: one population at intermediate state emission with energy peak of 0.15 MeV and another at low state emission with energy peak of 0.59 MeV. We interpret the spectrum at GeV – TeV energy range in the proton-photon interaction context and also find that the observations reported of ultra-high-energy cosmic rays and high-energy neutrinos can be explained through both target photon populations.
N. Fraija
Thu, 20 Feb 14
22/52
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