Detection of VHE gamma-ray emission from the distant blazar 1ES 1101-232 with HESS and broadband characterisation
Santangelo, A.; Ripken, J.; Carrigan, S.; Farnier, C.; Funk, S.; Lemoine-Goumard, M.; Venter, C.; Schlickeiser, R.; Petrucci, P. -O.; Giebels, B.; Fontaine, G.; Benbow, W.; Hauser, M.; Boisson, C.; Aharonian, F.; Akhperjanian, A. G.; Bazer-Bachi, A. R.; Beilicke, M.; Berge, D.; Bernlöhr, K.; Bolz, O.; Braun, I.; Brown, A. M.; Chadwick, P. M.; Chounet, L. -M.; Cornils, R.; Costamante, L.; Degrange, B.; Djannati-Ataï, A.; O'C. Drury, L.; Dubus, G.; Emmanoulopoulos, D.; Espigat, P.; Feinstein, F.; Gallant, Y. A.; Glicenstein, J. F.; Goret, P.; Hadjichristidis, C.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hofmann, W.; Holleran, M.; Horns, D.; de Jager, O. C.; Khélifi, B.; Komin, Nu.; Latham, I. J.; Le Gallou, R.; Lemière, A.; Martineau-Huynh, O.; Lohse, T.; Marcowith, A.; Masterson, C.; McComb, T. J. L.; de Naurois, M.; Nolan, S. J.; Noutsos, A.; Orford, K. J.; Osborne, J. L.; Panter, M.; Pelletier, G.; Pita, S.; Pühlhofer, G.; Punch, M.; Raubenheimer, B. C.; Raue, M.; Rayner, S. M.; Rob, L.; Rolland, L.; Rowell, G.; Sahakian, V.; Saugé, L.; Schlenker, S.; Schwanke, U.; Sol, H.; Steenkamp, R.; Stegmann, C.; Tavernet, J. -P.; Terrier, R.; Tluczykont, M.; Vasileiadis, G.; Vincent, P.; Völk, H. J.; Wagner, S. J.; Ward, M.; Lamanna, G.; Vialle, J. P.; Kendziorra, E.; Borrel, V.; Bühler, R.; Büsching, I.; Boutelier, T.; Coignet, G.; Dickinson, H. J.; Egberts, K.; Fiasson, A.; Füßling, M.; Glück, B.; Hauser, D.; Hoffmann, A.; Hoppe, S.; Jacholkowska, A.; Kerschhaggl, M.; Kosack, K.; Moulin, E.; Nedbal, D.; Rosier-Lees, S.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Superina, G.; Tam, P. H.; van Eldik, C.; Maurin, G.; Spanier, F.; Ferrero, E.; Brion, E.; Funk, Seb.; Martin, J. M.; Olive, J. -P.; Ranchon, S.; Schröder, R.; Spangler, D.
Germany, Armenia, France, United Kingdom, South Africa, Ireland, Czech Republic, Namibia
Abstract
Context: The blazar
Aims: VHE observations of blazars are used to investigate the inner parts of the blazar jets, and also to study the extragalactic background light (EBL) in the near-infrared band.
Methods: Observations in 2005 were conducted in a multiwavelength campaign, together with the RXTE satellite and optical observations. In 2004, simultaneous observations with XMM-Newton were obtained.
Results: 1ES 1101-232 was detected with HESS with an excess of 649 photons, at a significance of 10σ. The measured VHE γ-ray flux amounts to dN/dE = (5.63 ± 0.89) × 10-13 (E/TeV)-(2.94±0.20) cm-2 s-1 TeV-1, above a spectral energy threshold of 225 GeV. No significant variation of the VHE γ-ray flux on any time scale was found. 1ES 1101-232 exhibits a very hard spectrum, and at a redshift of z = 0.186, is the blazar with the highest confirmed redshift detected in VHE γ-rays so far.
Conclusions: The data allow the construction of truly simultaneous spectral energy distributions of the source, from the optical to the VHE band. Using an EBL model with ν Fν = 14 nWm-2 sr-1 at 1.5~μm as presented in Aharonian et al. (2006a) suggests an intrinsic VHE power output peak of the source at above 3 TeV.