UNI-MB - logo
UMNIK - logo
 
E-viri
Recenzirano Odprti dostop
  • VERY-HIGH ENERGY OBSERVATIO...
    Archer, A; BARNACKA, A; BEILICKE, M; Benbow, W; Berger, K; Bird, R; Biteau, J; Buckley, J H; Bugaev, V; Byrum, K

    The Astrophysical journal, 08/2014, Letnik: 790, Številka: 2
    Journal Article

    The Galactic center is an interesting region for high-energy (0.1-100 GeV) and very-high-energy (E > 100 GeV) gamma -ray observations. Potential sources of GeV/TeV gamma -ray emission have been suggested, e.g., the accretion of matter onto the supermassive black hole, cosmic rays from a nearby supernova remnant (e.g., Sgr A East), particle acceleration in a plerion, or the annihilation of dark matter particles. The Galactic center has been detected by EGRET and by Fermi/LAT in the MeV/GeV energy band. At TeV energies, the Galactic center was detected with moderate significance by the CANGAROO and Whipple 10m telescopes and with high significance by H.E.S.S., MAGIC, and VERITAS. We present the results from three years of VERITAS observations conducted at large zenith angles resulting in a detection of the Galactic center on the level of 18 standard deviations at energies above ~2.5 TeV. The energy spectrum is derived and is found to be compatible with hadronic, leptonic, and hybrid emission models discussed in the literature. Future, more detailed measurements of the high-energy cutoff and better constraints on the high-energy flux variability will help to refine and/or disentangle the individual models.