Very high energy gamma rays from the direction of Sagittarius A*

Abstract

We report the detection of a point-like source of very high energy (VHE) γ-rays coincident within 1′ of Sgr A*, obtained with the HESS array of Cherenkov telescopes. The γ-rays exhibit a power-law energy spectrum with a spectral index of -2.2 ± 0.09 ± 0.15 and a flux above the 165 GeV threshold of (1.82 ± 0.22) × 10-7 m-2 s-1. The measured flux and spectrum differ substantially from recent results reported in particular by the CANGAROO collaboration.

Astronomy & Astrophysics 425, L13-L17 (2004)
ArXiv pre-print

Auxiliary informations

Data points for Figure 4

HESS June/July dataset

Mean energy  Flux     Flux Error
   [TeV]       [/TeV cm^2 s]
   0.34    2.49e-11    1.14e-11
   0.49    1.43e-11    3.60e-12
   0.72    6.07e-12    1.60e-12
   1.06    1.63e-12    6.12e-13
   1.55    1.22e-12    3.33e-13
   2.28    4.43e-13    1.63e-13
   3.35    2.53e-13    8.54e-14

HESS July/August dataset

Mean energy  Flux     Flux Error
   [TeV]       [/TeV cm^2 s]

   0.28    4.92e-11    1.27e-11
   0.41    1.86e-11    4.07e-12
   0.60    6.23e-12    1.47e-12
   0.88    3.01e-12    6.39e-13
   1.30    1.73e-12    3.26e-13
   1.90    4.85e-13    1.36e-13
   2.79    2.59e-13    7.28e-14
   4.10    1.47e-13    3.49e-14
   6.02    4.62e-14    1.82e-14
   8.83    1.30e-14    1.07e-14

Remarks: Statistical errors only. Systematic error on energy scale estimated to 20%. See paper for details.

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