Each time a new “messenger” (different wavelengths of photons or a different particle) is added to the list of observables accessible to astrophysicists, the Universe appears in a new light: it has revealed surprising features and triggered new questions, ultimately changing our understanding of fundamental physics and cosmology. Examples include the new elementary particles discovered in cosmic rays in the 1930s and 1940s, the flavor oscillations of solar and atmospheric neutrinos, or revolutions. brought by radio or X-ray astronomy. Over the last decade, a new branch of astronomy has been born: high and very high energy gamma ray astronomy. In particular, 2OO4 was a very important year for gamma-ray astronomy. Firstly, it was the year which marked the 30th anniversary of the discovery of the compact radio source Sgr A* (Balick and Brown 1974) which is today strongly considered to be the revelation of a supermassive black hole of a mass of (3 imes 10^ {6} Modot ) which sits at the rotating center of the Galaxy, according to measurements of the movements of stars near the Galactic Center (GC). This is also the year when the first detection of gamma rays from a compact region of size (sim 10') around Sgr A* with the INTEGRAL observatory (exit{International Laboratory for Astrophysics of Gamma Rays} ) in the energy range from 20 to 100 keV (Bélanger et al 2004) and with the Cerenkov HESS (High Energy Stereoscopic System) telescope array between 165 and 10 TeV (Aharonian et al 2004) took place. The detection of a source of high-energy radiation that appears to be point-like and coincident with the galactic core appears to be the restatement of 30 years of observations. The GC is now also observed by the Fermi space observatory. When J.Co...... middle of paper......that is, less than (sim 100) Schwarzchild radii from the black hole). This fact must be explained by any model for the TeV gamma rays and appears to support the scenario in which the gamma rays are associated with electrons accelerated by the pulsar wind nebula. However, protons can be accelerated near the black hole, but be converted to gamma rays only after traveling a significant distance from the acceleration region (e.g. Atoyan n Dermer 2004; Aharonian n Neronov 2005; Ballantyne et al. 2007a ). In the scenario presented by Ballantyne et al. (2007a), it was assumed that proton acceleration occurs only at distances (sim 20-30) of the black hole's Scwarzchild radii (e.g. Liu et al. 2006). The particles would then diffuse away from the Sgr A* through the magnetized turbulent ISM? , until eventually colliding with the dense molecular gas of the circumnuclear disk.