Evidence for a Galactic γ-ray halo
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چکیده
We present quantitative statistical evidence for a γ-ray emission halo surrounding the Galaxy. Maps of the emission are derived. EGRET data were analyzed in a waveletbased non-parametric hypothesis testing framework, using a model of expected diffuse (Galactic + isotropic) emission as a null hypothesis. The results show a statistically significant large scale halo surrounding the center of the Milky Way as seen from Earth. The halo flux at high latitudes is somewhat smaller than the isotropic γ-ray flux at the same energy, though of the same order (O(10–10) ph cm s sr above 1 GeV).
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تاریخ انتشار 1998