Very high energy gamma rays from the composite SNR G 0.9+0.1

A&A 432, L25-L29 (2005)
DOI: 10.1051/0004-6361:200500022

Letter

Very high energy gamma rays from the composite SNR G 0.9+0.1

F. Aharonian¹, A. G. Akhperjanian², K.-M. Aye³, A. R. Bazer-Bachi⁴, M. Beilicke⁵, W. Benbow¹, D. Berge¹, P. Berghaus⁶, K. Bernlöhr^{1, 7}, C. Boisson⁸, O. Bolz¹, C. Borgmeier⁷, I. Braun¹, F. Breitling⁷, A. M. Brown³, J. Bussons Gordo⁹, P. M. Chadwick³, L.-M. Chounet¹⁰, R. Cornils⁵, L. Costamante^{1, 11}, B. Degrange¹⁰, A. Djannati-Ataï⁶, L. O'C. Drury¹², G. Dubus¹⁰, T. Ergin⁷, P. Espigat⁶, F. Feinstein⁹, P. Fleury¹⁰, G. Fontaine¹⁰, S. Funk¹, Y. A. Gallant⁹, B. Giebels¹⁰, S. Gillessen¹, P. Goret¹³, C. Hadjichristidis³, M. Hauser¹⁴, G. Heinzelmann⁵, G. Henri¹⁵, G. Hermann¹, J. A. Hinton¹, W. Hofmann¹, M. Holleran¹⁶, D. Horns¹, O. C. de Jager¹⁶, I. Jung^{1, 14}, B. Khélifi¹, Nu. Komin⁷, A. Konopelko^{1, 7}, I. J. Latham³, R. Le Gallou³, A. Lemière⁶, M. Lemoine¹⁰, N. Leroy¹⁰, T. Lohse⁷, A. Marcowith⁴, C. Masterson^{1, 11}, T. J. L. McComb³, M. de Naurois¹⁷, S. J. Nolan³, A. Noutsos³, K. J. Orford³, J. L. Osborne³, M. Ouchrif^{17, 11}, M. Panter¹, G. Pelletier¹⁵, S. Pita⁶, G. Pühlhofer^{1, 14}, M. Punch⁶, B. C. Raubenheimer¹⁶, M. Raue⁵, J. Raux¹⁷, S. M. Rayner³, I. Redondo^{10, 11}, A. Reimer¹⁸, O. Reimer¹⁸, J. Ripken⁵, L. Rob¹⁹, L. Rolland¹⁷, G. Rowell¹, V. Sahakian², L. Saugé¹⁵, S. Schlenker⁷, R. Schlickeiser¹⁸, C. Schuster¹⁸, U. Schwanke⁷, M. Siewert¹⁸, H. Sol⁸, R. Steenkamp²⁰, C. Stegmann⁷, J.-P. Tavernet¹⁷, R. Terrier⁶, C. G. Théoret⁶, M. Tluczykont^{10, 11}, G. Vasileiadis⁹, C. Venter¹⁶, P. Vincent¹⁷, B. Visser¹⁶, H. J. Völk¹ and S. J. Wagner¹⁴

¹ Max-Planck-Institut für Kernphysik, PO Box 103980, 69029 Heidelberg, Germany
e-mail: Jim.Hinton@mpi-hd.mpg.de
² Yerevan Physics Institute, 2 Alikhanian Brothers St., 375036 Yerevan, Armenia
³ University of Durham, Department of Physics, South Road, Durham DH1 3LE, UK
⁴ Centre d'Étude Spatiale des Rayonnements, CNRS/UPS, 9 Av. du Colonel Roche, BP 4346, 31029 Toulouse Cedex 4, France
⁵ Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, 22761 Hamburg, Germany
⁶ Physique Corpusculaire et Cosmologie, IN2P3/CNRS, Collège de France, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France
⁷ Institut für Physik, Humboldt-Universität zu Berlin, Newtonstr. 15, 12489 Berlin, Germany
⁸ LUTH, UMR 8102 du CNRS, Observatoire de Paris, Section de Meudon, 92195 Meudon Cedex, France
⁹ Groupe d'Astroparticules de Montpellier, IN2P3/CNRS, Université Montpellier II, CC85, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
¹⁰ Laboratoire Leprince-Ringuet, IN2P3/CNRS, École Polytechnique, 91128 Palaiseau, France
¹¹ European Associated Laboratory for Gamma-Ray Astronomy, jointly supported by CNRS and MPG
¹² Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin 2, Ireland
¹³ Service d'Astrophysique, DAPNIA/DSM/CEA, CE Saclay, 91191 Gif-sur-Yvette, France
¹⁴ Landessternwarte, Königstuhl, 69117 Heidelberg, Germany
¹⁵ Laboratoire d'Astrophysique de Grenoble, INSU/CNRS, Université Joseph Fourier, BP 53, 38041 Grenoble Cedex 9, France
¹⁶ Unit for Space Physics, North-West University, Potchefstroom 2520, South Africa
¹⁷ Laboratoire de Physique Nucléaire et de Hautes Énergies, IN2P3/CNRS, Universités Paris VI & VII, 4 place Jussieu, 75231 Paris Cedex 05, France
¹⁸ Institut für Theoretische Physik, Lehrstuhl IV: Weltraum und Astrophysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
¹⁹ Institute of Particle and Nuclear Physics, Charles University, V Holesovickach 2, 180 00 Prague 8, Czech Republic
²⁰ University of Namibia, Private Bag 13301, Windhoek, Namibia

(Received 15 December 2004 / Accepted 11 January 2005)

Abstract
Very high energy (>100 GeV) gamma-ray emission has been detected for the first time from the composite supernova remnant G 0.9+0.1 using the HESS $\,$ instrument. The source is detected with a significance of $\approx$ $13\sigma$ , and a photon flux above 200 GeV of ( $5.7\pm0.7_{\rm stat}\pm1.2_{\rm sys})\times10^{-12}$ cm^-2 s^-1, making it one of the weakest sources ever detected at TeV energies. The photon spectrum is compatible with a power law ( ${\rm d}N/{\rm d}E \propto E^{-\Gamma}$ ) with photon index $\Gamma = 2.40\pm0.11_{\rm stat}\pm0.20_{\rm sys}$ . The gamma-ray emission appears to originate in the plerionic core of the remnant, rather than the shell, and can be plausibly explained as inverse Compton scattering of relativistic electrons.

Key words: ISM: supernova remnants -- ISM: individual objects: G 0.9+0.1 -- gamma-rays: observations

SIMBAD Objects