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Astronomy and Astrophysics 481 (2008) L103-L107
Discovery of VHE gamma-rays from the high-frequency-peaked BL Lac object RGB J0152+017
F. Aharonian, A.G. Akhperjanian, A.R. Bazer-Bachi1, B. Behera, M. Beilicke, W. Benbow, D. Berge, K. Bernlöhr, C. Boisson2, O. Bolz, V. Borrel1, I. Braun, E. Brion3, A.M. Brown, R. Bühler, T. Bulik, I. Büsching, T. Boutelier4, S. Carrigan, P.M. Chadwic, L.-M. Chounet5, A.C. Clapson, G. Coignet6, R. Cornils, L. Costamante, B. Degrange5, H.J. Dickinson, A. Djannati-Ataï7, W. Domainko, L.O'C. Drury, G. Dubus5, J. Dyks, K. Egberts, D. Emmanoulopoulos, P. Espigat7, C. Farnier8, F. Feinstein8, A. Fiasson8, A. F¨orster, G. Fontaine5, Y. Fukui, Seb. Funk, S. Funk, M. Füßling, Y.A. Gallant8, B. Giebels5, J.F. Glicenstein3, B. Glück, P. Goret3, C. Hadjichristidis, D. Hauser, M. Hauser, G. Heinzelmann, G. Henri4, G. Hermann, J.A. Hinton, A. Hoffmann, W. Hofmann, M. Holleran, S. Hoppe, D. Horns, A. Jacholkowska8, O.C. de Jager, E. Kendziorra, M. Kerschhagg, B. Khélifi5, Nu. Komin8, K. Kosack, G. Lamanna6, I.J. Latham, R. Le Gallou, A. Lemière7, M. Lemoine-Goumard5, J.-P. Lenain2, T. Lohse, J.M. Martin2, O. Martineau-Huynh9, A. Marcowith8, C. Masterson, G. Maurin7, T.J.L. Mccomb, R. Moderski, Y. Moriguchi, E. Moulin8, M. De Naurois9, D. Nedbal, S.J. Nolan, J.-P. Olive1, K.J. Orford, J.L. Osborne, M. Ostrowski, M. Panter, G. Pedaletti, G. Pelletier4, P.-O. Petrucci4, S. Pita7, G. P¨uhlhofer, M. Punch7, S. Ranchon6, B.C. Raubenheimer, M. Raue, S.M. Rayner, O. Reimer, M. Renaud, J. Ripken, L. Rob, L. Rolland3, S. Rosier-Lees6, G. Rowell, B. Rudak, J. Ruppel, V. Sahakian, A. Santangelo, L. Saugé, S. Schlenker, R. Schlickeiser, R. Schroder, U. Schwanke, S. Schwarzburg, S. Schwemmer, A. Shalchi, H. Sol2, D. Spangler, Ł. Stawarz, R. Steenkamp, C. Stegmann, G. Superina5, T. Takeuchi, P.H. Tam, J.-P. Tavernet9, R. Terrier7, C. Van Eldik, G. Vasileiadis8, C. Venter, J.P. Vialle6, P. Vincent9, M. Vivier3, H.J. Volk, F. Volpe5, S.J. Wagner, M. Ward
HESS Collaboration(s)
(02/2008)

Aims: The BL Lac object RGB J0152+017 (z=0.080) was predicted to be a very high-energy (VHE; > 100 GeV) gamma-ray source, due to its high X-ray and radio fluxes. Our aim is to understand the radiative processes by investigating the observed emission and its production mechanism using the High Energy Stereoscopic System (H.E.S.S.) experiment. Methods: We report recent observations of the BL Lac source RGB J0152+017 made in late October and November 2007 with the H.E.S.S. array consisting of four imaging atmospheric Cherenkov telescopes. Contemporaneous observations were made in X-rays by the Swift and RXTE satellites, in the optical band with the ATOM telescope, and in the radio band with the Nancay Radio Telescope. Results: A signal of 173 gamma-ray photons corresponding to a statistical significance of 6.6 sigma was found in the data. The energy spectrum of the source can be described by a powerlaw with a spectral index of 2.95+/-0.36stat+/-0.20syst. The integral flux above 300 GeV corresponds to ~2% of the flux of the Crab nebula. The source spectral energy distribution (SED) can be described using a two-component non-thermal synchrotron self-Compton (SSC) leptonic model, except in the optical band, which is dominated by a thermal host galaxy component. The parameters that are found are very close to those found in similar SSC studies in TeV blazars. Conclusions: RGB J0152+017 is discovered as a source of VHE gamma-rays by H.E.S.S. The location of its synchrotron peak, as derived from the SED in Swift data, allows clearly classification it as a high-frequency-peaked BL Lac (HBL).
1 :  CESR - Centre d'étude spatiale des rayonnements
2 :  LUTH - Laboratoire Univers et Théories
3 :  DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
4 :  LAOG - Laboratoire d'Astrophysique de Grenoble
5 :  LLR - Laboratoire Leprince-Ringuet
6 :  LAPP - Laboratoire d'Annecy le Vieux de Physique des Particules
7 :  APC - UMR 7164 - AstroParticule et Cosmologie
8 :  LPTA - Laboratoire de Physique Théorique et Astroparticules
9 :  LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
APC - AHE
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique

Planète et Univers/Astrophysique/Cosmologie et astrophysique extra-galactique

Planète et Univers/Astrophysique
Lien vers le texte intégral : 
http://fr.arXiv.org/abs/0802.4021