159 articles – 2004 Notices  [english version]
HAL : in2p3-00124806, version 1

Fiche détaillée  Récupérer au format
Astronomy and Astrophysics 455 (2006) 461-466
Discovery of Very High Energy Gamma-Ray Emission from the BL Lac Object H2356-309 with the H.E.S.S. Cherenkov Telescopes
F. Aharonian, A. G. Akhperjanian, A. R. Bazer-Bachi1, M. Beilicke, W. Benbow, D. Berge, K. Bernlöhr, C. Boisson2, O. Bolz, V. Borrel1, I. Braun, F. Breitling, A. M. Brown, R. Bühler, I. Büsching, S. Carrigan, P. M. Chadwick, L.-M. Chounet3, R. Cornils, L. Costamante, B. Degrange3, H. J. Dickinson, A. Djannati-Ataï4, L. O'C. Drury, G. Dubus3, K. Egberts, D. Emmanoulopoulos, P. Espigat4, F. Feinstein5, E. Ferrero, G. Fontaine3, Seb. Funk, S. Funk, Y. A. Gallant5, B. Giebels3, J. F. Glicenstein6, P. Goret6, C. Hadjichristidis, D. Hauser, M. Hauser, G. Heinzelmann, G. Henri7, G. Hermann, J. A. Hinton, W. Hofmann, M. Holleran, D. Horns, A. Jacholkowska5, O. C. De Jager, B. Khélifi3, Nu. Komin, A. Konopelko, I. J. Latham, R. Le Gallou, A. Lemière4, M. Lemoine-Goumard3, T. Lohse, J. M. Martin, O. Martineau-Huynh, A. Marcowith1, C. Masterson, T. J. L. Mccomb, M. De Naurois, D. Nedbal, S. J. Nolan, A. Noutsos, K. J. Orford, J. L. Osborne, M. Ouchrif, M. Panter, G. Pelletier7, S. Pita4, G. Pühlhofer, M. Punch4, B. C. Raubenheimer, M. Raue, S. M. Rayner, A. Reimer, O. Reimer, J. Ripken, L. Rob, L. Rolland, G. Rowell, V. Sahakian, L. Saugé7, S. Schlenker, R. Schlickeiser, U. Schwanke, H. Sol2, D. Spangler, F. Spanier, R. Steenkamp, C. Stegmann, G. Superina3, J.-P. Tavernet, R. Terrier4, C.G. Théoret4, M. Tluczykont3, C. Van Eldik, G. Vasileiadis5, C. Venter, P. Vincent, H. J. Völk, S. J. Wagner, M. Ward
HESS Collaboration(s)

The extreme synchrotron BL Lac object H2356-309, located at a redshift of z = 0.165, was observed from June to December 2004 with a total exposure of approx. 40 h live-time with the H.E.S.S. (High Energy Stereoscopic System) array of atmospheric-Cherenkov telescopes (ACTs). Analysis of this data set yields, for the first time, a strong excess of 453 gamma-rays (10 standard deviations above background) from H2356-309, corresponding to an observed integral flux above 200 GeV of I(>200GeV) = (4.1+-0.5) 10^12 cm^-2.s^-1 (statistical error only). The differential energy spectrum of the source between 200 GeV and 1.3 TeV is well-described by a power law with a normalisation (at 1 TeV) of N_0 = (3.00 +- 0.80_stat +- 0.31_sys) 10^-13 cm^-2.s^-1.TeV^-1 and a photon index of Gamma = 3.09 +- 0.24_stat +- 0.10_sys. H2356-309 is one of the most distant BL Lac objects detected at very-high-energy gamma-rays so far. Results from simultaneous observations from ROTSE-III (optical), RXTE (X-rays) and NRT (radio) are also included and used together with the H.E.S.S. data to constrain a single-zone homogeneous synchrotron self-Compton (SSC) model. This model provides an adequate fit to the H.E.S.S. data when using a reasonable set of model parameters.
1 :  CESR - Centre d'étude spatiale des rayonnements
2 :  LUTH - Laboratoire Univers et Théories
3 :  LLR - Laboratoire Leprince-Ringuet
4 :  APC - UMR 7164 - AstroParticule et Cosmologie
5 :  LPTA - Laboratoire de Physique Théorique et Astroparticules
6 :  DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée
7 :  LAOG - Laboratoire d'Astrophysique de Grenoble
Physique/Astrophysique/Cosmologie et astrophysique extra-galactique

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

Planète et Univers/Astrophysique
gamma rays: observations – galaxies: active – galaxies: BL Lacertae objects: individual: H 2356-309
Lien vers le texte intégral :