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Simultaneous H.E.S.S. and Chandra observations of Sagittarius A* during an X-ray flare

By F. Aharonian, A.G. Akhperjanian, U. Barres De Almeida, A.R. Bazer-Bachi, Y. Becherini, B. Behera, W. Benbow, K. Bernlöhr, C. Boisson, A. Bochow, V. Borrel, I. Braun, E. Brion, J. Brucker, P. Brun, R. Bühler, T. Bulik, I. Büsching, T. Boutelier, S. Carrigan, P.M. Chadwick, A. Charbonnier, R.C.G. Chaves, A. Cheesebrough, L.-M. Chounet, A.C. Clapson, G. Coignet, B. Degrange, C. Deil, H.J. Dickinson, A. Djannati-Ataï, W. Domainko, L.O'C. Drury, F. Dubois, G. Dubus, J. Dyks, M. Dyrda, K. Egberts, D. Emmanoulopoulos, P. Espigat, C. Farnier, F. Feinstein, A. Fiasson, A. Förster, G. Fontaine, M. Füsling, S. Gabici, Y.A. Gallant, L. Gérard, B. Giebels, J.F. Glicenstein, B. Glück, P. Goret, C. Hadjichristidis, D. Hauser, M. Hauser, S. Heinz, G. Heinzelmann, G. Henri, G. Hermann, J.A. Hinton, A. Hoffmann, W. Hofmann, M. Holleran, S. Hoppe, D. Horns, A. Jacholkowska, O.C. De Jager, I. Jung, K. Katarzy'Nski, S. Kaufmann, E. Kendziorra, M. Kerschhaggl, D. Khangulyan, B. Khélifi, D. Keogh, Nu. Komin, K. Kosack, G. Lamanna, J.-P. Lenain, T. Lohse, V. Marandon, J.M. Martin, O. Martineau-Huynh, A. Marcowith, D. Maurin, T.J.L. Mccomb, M.C. Medina, R. Moderski, Emmanuel Moulin, M. Naumann-Godo, M. De Naurois, D. Nedbal, D. Nekrassov, J. Niemiec, S.J. Nolan, S. Ohm, J.-F. Olive, E. De Oña Wilhelmi, K.J. Orford, J.L. Osborne, M. Ostrowski, M. Panter, G. Pedaletti, G. Pelletier, P.-O. Petrucci, S. Pita, G. Pühlhofer, M. Punch, A. Quirrenbach, B.C. Raubenheimer, M. Raue, S.M. Rayner, M. Renaud, F. Rieger, J. Ripken, L. Rob, S. Rosier-Lees, G. Rowell, B. Rudak, C.B. Rulten, J. Ruppel, V. Sahakian, A. Santangelo, R. Schlickeiser, F.M. Schöck, R. Schröder, U. Schwanke, S. Schwarzburg, S. Schwemmer, A. Shalchi, J.L. Skilton, H. Sol, D. Spangler, L. Stawarz, R. Steenkamp, C. Stegmann, G. Superina, P.H. Tam, J.-P. Tavernet, R. Terrier, O. Tibolla, C. Van Eldik, G. Vasileiadis, C. Venter, J.P. Vialle, P. Vincent, M. Vivier, H.J. Völk, F. Volpe, S.J. Wagner, M. Ward, A.A. Zdziarski and A. Zech


5 pages, 2 figuresThe rapidly varying (~10 minute timescale) non-thermal X-ray emission observed from Sgr A* implies that particle acceleration is occuring close to the event horizon of the supermassive black hole. The TeV gamma-ray source HESS J1745-290 is coincident with Sgr A* and may be closely related to its X-ray emission. Simultaneous X-ray and TeV observations are required to elucidate the relationship between these objects. We report on joint H.E.S.S./Chandra observations performed in July 2005, during which an X-ray flare was detected. Despite a factor of 9 increase in the X-ray flux of Sgr A*, no evidence is found for an increase in the TeV gamma-ray flux from this region. We find that an increase in the gamma-ray flux of a factor of 2 or greater can be excluded at a confidence level of 99%. This finding disfavours scenarios in which the keV and TeV emission are associated with the same population of accelerated particles and in which the bulk of the gamma-ray emission is produced within ~10^{14} cm (~100 R_S) of the supermassive black hole

Topics: X-rays:individual sources:Sgr A, gamma-rays:observations, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO]
Publisher: 'EDP Sciences'
Year: 2008
DOI identifier: 10.1051/0004-6361:200810912
OAI identifier: oai:HAL:in2p3-00348809v1
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