Galactic Center at Very High Energies Essay -- The Universe, Black Hol

Every succession a new messenger (different photon wavelengths or a different particle) has added to the arguing of observables accessible to astrophysicists, the Universe has appeared under a new light it has revealed affect features and triggered new questions, ultimately changing our understanding of fundamental physics and cosmology.Examples acknowledge the new elementary particles discovered in cosmic rays in the 30s and 40s, tint oscillations from the solar and atmospheric neutrinos, or the revolutions brought by intercommunicate or roentgen ray astronomy. The last decade, a new branch of astronomy was born proud energy and very high energy gamma-ray astronomy.Especially, 2OO4 was a very importand class for the gamma-rays astronomy. Firstly it was the year that marked the 30th aniversary of the discovery of the compact radio source Sgr A* (Balick and Brown 1974) which is now strongly believed to be the manifestation of a supermassive black hole of a mass of (3 imes 10 6 M odot ) that seats in the rotanional center of the Galaxy, according to the measurments of star motions well-nigh the Galactic Center (GC). Moreover it was the year that the first detection of gamma-rays from a compact region of size (sim 10) around Sgr A* with the INTEGRAL (extit outside(a) Gamma-Ray Astrophysics Laboratory ) observatory in the energy rage from 20 to ampere-second keV (Belanger et al 2004) and with the HESS (High Energy Stereoscopic System) Cerenkov telescope array between clxv and 10 TeV (Aharonian et al 2004) took place. The detection of a high energy beam source that appears to be pointlike and coincident with the Galactic Nucleus seems to be the paraphrase of 30 years of observations. The GC is now observed also by the Fermi space observatory. When J.Co... ...i.e. within (sim 100 ) Schwarzchild radii of the black hole). This fact mustiness be explained by any model for the TeV gamma-rays and it seems to support the scenario where the gamma-rays are a ssosiated with electrons accelarated by the pulsar wind nebula.However, protons may be accelarated close to the black hole, but be converted to gamma-rays only after travelling a significant duration away from the accelaration region (e.g. Atoyan n Dermer 2004 Aharonian n Neronov 2005 Ballantyne et al. 2007a). In the scenario presented by Ballantyne et al. (2007a), proton accelaration was fake to occur at distances only (sim 20-30 ) Scwarzchild radii from the black hole (e.g. Liu et al. 2006). The particles would then string out away from the Sgr A* through the magnetized turbulent ISM ? , until by chance colliding with the dense molecular gas in the circumnuclear disk.