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Title: PKS2005-489 at VHE: four years of monitoring with HESS and simultaneous multi-wavelength observations
Authors: Acero, F.
Aharonian, F.
Akhperjanian, A. G.
Anton, G.
de Almeida UB
Bazer-Bachi, A. R.
Becherini, Y.
Behera, B.
Benbow, W.
Bernloehr, K.
Bochow, A.
Katz, U.
Ripken, J.
Kaufmann, S.
Kerschhaggl, M.
Khangulyan, D.
Dalton, M.
Khelifi, B.
Keogh, D.
Klochkov, D.
Kluzniak, W.
Superina, G.
de Naurois M
Pelletier, G.
Kneiske, T.
Rob, L.
Komin, N.
Kosack, K.
Schwarzburg, S.
Kossakowski, R.
Lamanna, G.
Lenain, J. -. P.
Espigat, P.
Lohse, T.
Marandon, V.
Martineau-Huynh, O.
Marcowith, A.
Bolmont, J.
Rosier-Lees, S.
Nedbal, D.
Schwemmer, S.
Masbou, J.
Maurin, D.
Szostek, A.
McComb, T. J. L.
Nekrassov, D.
Nicholas, B.
Niemiec, J.
Boisson, C.
Nolan, S. J.
Ohm, S.
Costamante, L.
Shalchi, A.
Petrucci, P. -. O.
Tam, P. H.
Olive, J. -. F.
Wilhelmi, E. D. O.
Orford, K. J.
Pita, S.
Puehlhofer, G.
Punch, M.
Coignet, G.
Quirrenbach, A.
Raubenheimer, B. C.
Eger, P.
Tavernet, J. -. P.
Rowell, G.
Raue, M.
Rayner, S. M.
Renaud, M.
Rudak, B.
Rulten, C. B.
Ruppel, J.
Egberts, K.
Sahakian, V.
Santangelo, A.
Moderski, R.
Sikora, M.
Schlickeiser, R.
Brucker, J.
Schoeck, F. M.
Skilton, J. L.
Sol, H.
Stawarz, L.
Gerbig, D.
Steenkamp, R.
Brun, F.
Terrier, R.
Stegmann, C.
Daniel, M. K.
Stinzing, F.
Tibolla, O.
Tluczykont, M.
van Eldik C
Hoffmann, A.
Brun, P.
Davids, I. D.
Vasileiadis, G.
Fallon, L.
Venter, C.
Venter, L.
Giebels, B.
Vialle, J. P.
Vincent, P.
Vivier, M.
Arribas, M. P.
Voelk, H. J.
Volpe, F.
Wagner, S. J.
Ward, M.
Degrange, B.
Farnier, C.
Buehler, R.
Glicenstein, J. F.
Zdziarski, A. A.
Zech, A.
Hofmann, W.
Collaboration, H. E. S. S.
Bulik, T.
Buesching, I.
Boutelier, T.
Chadwick, P. M.
Charbonnier, A.
Chaves, R. C. G.
Mehault, J.
Glueck, B.
Deil, C.
Hofverberg, P.
Cheesebrough, A.
Chounet, L. -. M.
Clapson, A. C.
Dickinson, H. J.
Djannati-Atai, A.
Domainko, W.
Medina, M. C.
Drury, L. O.
Dubois, F.
Panter, M.
Holleran, M.
Fegan, S.
Dubus, G.
Dyks, J.
Dyrda, M.
Feinstein, F.
Fiasson, A.
Foerster, A.
Ostrowski, M.
Fontaine, G.
Fuessling, M.
Borrel, V.
Goret, P.
Gabici, S.
Gallant, Y. A.
Gerard, L.
Goering, D.
Hauser, M.
Heinz, S.
Rieger, F.
Heinzelmann, G.
Henri, G.
Hoppe, S.
Hermann, G.
Moulin, E.
Hinton, J. A.
Horns, D.
Jacholkowska, A.
de Jager OC
Schwanke, U.
Jahn, C.
Naumann-Godo, M.
Jung, I.
Pedaletti, G.
Katarzynski, K.
First Published: 9-Mar-2010
Publisher: EDP Sciences for European Southern Observatory (ESO)
Citation: Astronomy & Astrophysics, 2010, 511
Abstract: Aims. Our aim is to study the very high energy (VHE; E>100 GeV) γ-ray emission from BL Lac objects and the evolution in time of their broad-band spectral energy distribution (SED). Methods. VHE observations of the high-frequency peaked BL Lac object PKS 2005-489 were made with the High Energy Stereoscopic System (HESS) from 2004 through 2007. Three simultaneous multi-wavelength campaigns at lower energies were performed during the HESS data taking, consisting of several individual pointings with the XMM-Newton and RXTE satellites. Results. A strong VHE signal, ~17σ total, from PKS 2005-489 was detected during the four years of HESS observations (90.3 h live time). The integral flux above the average analysis threshold of 400 GeV is ~3% of the flux observed from the Crab Nebula and varies weakly on time scales from days to years. The average VHE spectrum measured from ~300 GeV to ~5 TeV is characterized by a power law with a photon index, . At X-ray energies the flux is observed to vary by more than an order of magnitude between 2004 and 2005. Strong changes in the X-ray spectrum () are also observed, which appear to be mirrored in the VHE band. Conclusions. The SED of PKS 2005-489, constructed for the first time with contemporaneous data on both humps, shows significant evolution. The large flux variations in the X-ray band, coupled with weak or no variations in the VHE band and a similar spectral behavior, suggest the emergence of a new, separate, harder emission component in September 2005.
DOI Link: 10.1051/0004-6361/200913073
ISSN: 0004-6361
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © 2010 ESO. Reproduced with permission from Astronomy & Astrophysics, © ESO.
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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