The Nature of 3EG J1746-2851 in the Nucleus of the Galaxy
  There are a number of candidate sources that are considered to be responsible for the origin of the EGRET source 3EG J1746--2851 (Hartman et al. 1999). The lack of clear identification of this source with any known sources in this region is due to the complexity and the richness of the environment of the Galactic center as well as the low spatial resolution of the EGRET observations. Four hypotheses, which include the interaction of something with something else, are described to account for the energetics and the spectrum of the $\gamma$-ray emission from the enigmatic EGRET source which lies within 0.2$^0$ of the Galactic center. The possible interaction sites result from the following: i) the nonthermal filaments of the radio Arc & G0.13-0.13 molecular cloud, ii) the supernova remnant Sgr A East & the 50 km s$^{-1}$ molecular cloud, iii) the magnetized filaments of the Arc & M0.20-0.033 molecular cloud and iv) the relativistic particles of the Arches cluster & its own stellar radiations field. 
F. Yusef-Zadeh (Northwestern U.)