PKS 2005-489 at VHE: Four Years of Monitoring with HESS and Simultaneous Multi-wavelength Observations

Fabio Acero , F. Aharonian , A.G. Akhperjanian , G. Anton , U. Barres de Almeida , A.R. Bazer-Bachi (1) , Y. Becherini (2) , B. Behera , W. Benbow , K. Bernlöhr , A. Bochow , C. Boisson (3) , J. Bolmont (4) , V. Borrel (1) , J. Brucker , F. Brun (4) , P. Brun (5) , R. Bühler , T. Bulik , I. Büsching , T. Boutelier (6) , P.M. Chadwick , A. Charbonnier (4) , R.C.G. Chaves , A. Cheesebrough , L.-M. Chounet (7) , A.C. Clapson , G. Coignet (8) , L. Costamante , M. Dalton , M.K. Daniel , I.D. Davids , B. Degrange (7) , C. Deil , H.J. Dickinson , A. Djannati-Ataï (9) , W. Domainko , L.O'C. Drury , F. Dubois (8) , G. Dubus (6) , J. Dyks , M. Dyrda , K. Egberts , P. Eger , P. Espigat (2) , L. Fallon , C. Farnier (10) , S. Fegan , F. Feinstein (10) , A. Fiasson (8) , A. Förster , G. Fontaine (7) , M. Füssling , S. Gabici , Y.A. Gallant (10) , L. Gérard (2) , D. Gerbig , B. Giebels (7) , J.F. Glicenstein (5) , B. Glück , P. Goret (5) , D. Göring , M. Hauser , S. Heinz , G. Heinzelmann , G. Henri (6) , G. Hermann , J.A. Hinton , A. Hoffmann , W. Hofmann , P. Hofverberg , M. Holleran , S. Hoppe , D. Horns , A. Jacholkowska (10) , O.C. de Jager , C. Jahn , I. Jung , K. Katarzynski , U. Katz , S. Kaufmann , M. Kerschhaggl , D. Khangulyan , B. Khélifi (7) , D. Keogh , D. Klochkov , W. Kluzniak , T. Kneiske , Nu. Komin (5) , K. Kosack , R. Kossakowski (8) , G. Lamanna (8) , J.-P. Lenain (3) , T. Lohse (3) , V. Marandon (2) , O. Martineau-Huynh (4) , A. Marcowith (10) , Julien Masbou (8) , D. Maurin (4) , T.J.L. Mccomb , M.C. Medina (3) , J. Méhault , R. Moderski , Emmanuel Moulin (5) , M. Naumann-Godo (7) , M. de Naurois (4) , D. Nedbal , D. Nekrassov , B. Nicholas , J. Niemiec , S.J. Nolan , S. Ohm , J.-F. Olive (1) , E. de Oña Wilhelmi , K.J. Orford , M. Ostrowski , M. Panter , M. Paz Arribas , G. Pedaletti , G. Pelletier (6) , P.-O. Petrucci (6) , S. Pita (2) , G. Pühlhofer , M. Punch (2) , A. Quirrenbach , B.C. Raubenheimer , M. Raue , S.M. Rayner , M. Renaud (2) , F. Rieger , J. Ripken , L. Rob , S. Rosier-Lees (8) , G. Rowell , B. Rudak , C.B. Rulten , J. Ruppel , V. Sahakian , A. Santangelo , R. Schlickeiser , F.M. Schöck , U. Schwanke (3) , S. Schwarzburg , S. Schwemmer , A. Shalchi , M. Sikora , J.L. Skilton , H. Sol (3) , Ł. Stawarz , R. Steenkamp , C. Stegmann (3) , F. Stinzing , G. Superina (7) , A. Szostek (6) , P.H. Tam , J.-P. Tavernet (4) , R. Terrier (2) , O. Tibolla , M. Tluczykont , C. van Eldik , G. Vasileiadis (10) , C. Venter , L. Venter (3) , J.P. Vialle (8) , P. Vincent (4) , M. Vivier (5) , H.J. Völk , F. Volpe (7) , S.J. Wagner , M. Ward , A.A. Zdziarski , A. Zech (3)

1 CESR - Centre d'étude spatiale des rayonnements
2 APC (UMR_7164) - AstroParticule et Cosmologie
3 LUTH (UMR_8102) - Laboratoire Univers et Théories
4 LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
5 IRFU - Institut de Recherches sur les lois Fondamentales de l'Univers
6 LAOG - Laboratoire d'Astrophysique de Grenoble
7 LLR - Laboratoire Leprince-Ringuet
8 LAPP - Laboratoire d'Annecy de Physique des Particules
9 APC - AHE - APC - Astrophysique des Hautes Energies
10 LPTA - Laboratoire de Physique Théorique et Astroparticules

VHE observations of PKS 2005-489 were made with HESS from 2004 through 2007, together with three simultaneous multi-wavelength campaigns performed with XMM-Newton and RXTE in 2004 and 2005. A strong VHE signal, ~17sigma total, is detected during the four years of HESS observations (90.3 hrs live time). The integral flux above the average analysis threshold of 400 GeV is ~3% of the Crab and varies weakly on time-scales from days to years. 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 (DeltaGamma~0.7) are also observed, which appear to be mirrored in the VHE band. 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.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Cosmologie et astrophysique extra-galactique [astro-ph.CO]

Fabio Acero, F. Aharonian, A.G. Akhperjanian, G. Anton, U. Barres de Almeida, et al.. PKS 2005-489 at VHE: Four Years of Monitoring with HESS and Simultaneous Multi-wavelength Observations. Astronomy and Astrophysics - A&A, 2010, 511, pp.A52. ⟨10.1051/0004-6361/200913073⟩. ⟨in2p3-00445182⟩