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

F. Aharonian , A.G. Akhperjanian , K.-M. Aye , A.R. Bazer-Bachi (1) , M. Beilicke , W. Benbow , D. Berge , P. Berghaus (2) , K. Bernlohr , O. Bolz , C. Boisson (3) , C. Borgneier , F. Breitling , A.M. Brown , J. Bussons Gordo (4) , P.M. Chadwick , V.R. Chitnis (5) , L.-M. Chounet (6) , R. Cornils , B. Degrange (6) , A. Djannati-Atai (2) , L.O'C. Drury , T. Ergin , P. Espigat (2) , F. Feinstein (4) , P. Fleury (6) , G. Fontaine (6) , S. Funk , Y. Gallant (4) , B. Giebels (6) , S. Gillessen , P. Goret (7) , J. Guy (5) , C. Hadjichristidis , M. Hauser , G. Heinzelmann , G. Henri (8) , G. Hermann , M. Holleran , D. Horns , O.C. De Jager , I. Jung , B. Khelifi , Nu. Komin , A. Konopelko , I.J. Latham , R. Le Gallou , M. Lemoine (6) , N. Leroy (6) , T. Lohse , A. Marcowith (1) , C. Masterson , T.J.L. Mccomb , M. De Naurois (5) , S.J. Nolan , A. Noutsos , K.J. Orford , M. Ouchrif (5) , M. Panter , G. Pelletier (8) , S. Pita (2) , M. Pohl , G. Puhlhofer , M. Punch (2) , B.C. Raubenheimer , M. Raue , J. Raux (5) , I. Redondo (6) , A. Reimer , O. Reimer , J. Ripken , M. Rivoal (5) , L. Rob , L. Rolland (5) , G. Rowell , V. Sahakian , L. Sauge (8) , S. Schlenker , C. Schuster , U. Schwanke , M. Siewert , H. Sol (3) , R. Steenkamp , C. Stegmann , J.-P. Tavernet (5) , C.G Theoret (2) , M. Tluczykont (6) , D.J. van Der Walt , G. Vasileiadis (4) , P. Vincent (5) , B. Visser , H.J. Volk , S.J. Wagner

1 CESR - Centre d'étude spatiale des rayonnements
2 PCC - Physique Corpusculaire et Cosmologie - Collège de France
3 LUTH (UMR_8102) - Laboratoire Univers et Théories
4 LPTA - Laboratoire de Physique Théorique et Astroparticules
5 LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
6 LLR - Laboratoire Leprince-Ringuet
7 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
8 LAOG - Laboratoire d'Astrophysique de Grenoble

We report the detection of a point-like source of very high energy (VHE) gamma-rays coincident within 1' of Sgr A*, obtained with the H.E.S.S. array of Cherenkov telescopes. The gamma-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) \times 10^{-7} m^{-2} s^{-1}. The measured flux and spectrum differ substantially from recent results reported in particular by the CANGAROO collaboration.

Domaines: Astrophysique [astro-ph]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]

F. Aharonian, A.G. Akhperjanian, K.-M. Aye, A.R. Bazer-Bachi, M. Beilicke, et al.. Very high-energy gamma rays from the direction of Sagittarius A. Astronomy and Astrophysics - A&A, 2004, 425, pp.L13-L17. ⟨10.1051/0004-6361:200400055⟩. ⟨in2p3-00022258⟩