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Abstract: We examine the effect of gamma-ray absorption by the extragalactic infraredradiation on intrinsic spectra predicted for 1ES0229+200 and compare ourresults with the observational data. We find agreement with our previousresults on the shape of the IR spectral energy distribution SED, contrary tothe recent assertion of the HESS group. Our analysis indicates that 1ES0229+200has a very hard intrinsic spectrum with a spectral index between 1.1 +- 0.3and 1.5 +- 0.3 in the energy range between ~0.5 TeV and ~15 TeV. Under theassumptions that 1 the SED models of Stecker, Malkan and Scully 2006 arereasonable as derived from numerous detailed IR observations, and 2 spectralindexes in the range 1 < \Gamma < 1.5 have been shown to be obtainable fromrelativistic shock acceleration under the astrophysical conditions extant inblazar flares Stecker, Baring and Summerlin 2007, the fits to the observationsof 1ES0229+200 using our previous IR SEDs are consistent with both the IR andgamma-ray observations. Our analysis presents evidence indicating that theenergy spectrum of relativistic particles in 1ES0229+200 is produced byrelativistic shock acceleration, producing an intrinsic gamma-ray spectrum withindex 1 < \Gamma < 1.5 and with no evidence of a peak in the SED up to energies~15 TeV.

Author: F.W. Stecker NASA-GSFC and S.T. Scully James Madison Univ.


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