2011ApJ...735..115H

We present a detailed analysis of the γ-ray emission from HESS J1745-303 with the data obtained by the Fermi Gamma-ray Space Telescope in its first ∼29 month observation. The source can clearly be detected at the levels of ∼18σ and ∼6σ in 1-20 GeV and 10-20 GeV, respectively. We do not find any evidence of the variability seen in the results obtained by the Compton Gamma-ray Observatory. Most of the emission in 10-20 GeV is found to coincide with region C of HESS J1745-303. A simple power law is sufficient to describe the GeV spectrum with a photon index of Γ ∼ 2.6. The power-law spectrum inferred in the GeV regime can be connected to that of a particular spatial component of HESS J1745-303 in 1-10 TeV without any spectral break. These properties impose independent constraints for understanding the nature of this "dark particle accelerator."