Abramowski, A. and Acero, F. and Aharonian, F. and Akhperjanian, A.G. and Anton, G. and Balenderan, S. and Balzer, A. and Barnacka, A. and Becherini, Y. and Becker Tjus, J. and Bernlöhr, K. and Birsin, E. and Biteau, J. and Bochow, A. and Boisson, C. and Bolmont, J. and Bordas, P. and Brucker, J. and Brun, F. and Brun, P. and Bulik, T. and Carrigan, S. and Casanova, S. and Cerruti, M. and Chadwick, P.M. and Charbonnier, A. and Chaves, R.C.G. and Cheesebrough, A. and Cologna, G. and Conrad, J. and Couturier, C. and Dalton, M. and Daniel, M.K. and Davids, I.D. and Degrange, B. and Deil, C. and deWilt, P. and Dickinson, H.J. and Djannati-Ataï, A. and Domainko, W. and Drury, L.O'C. and Dubus, G. and Dutson, K. and Dyks, J. and Dyrda, M. and Egberts, K. and Eger, P. and Espigat, P. and Fallon, L. and Farnier, C. and Fegan, S. and Feinstein, F. and Fernandes, M.V. and Fernandez, D. and Fiasson, A. and Fontaine, G. and Förster, A. and Füßling, M. and Gajdus, M. and Gallant, Y.A. and Garrigoux, T. and Gast, H. and Giebels, B. and Glicenstein, J.F. and Glück, B. and Göring, D. and Grondin, M.-H. and Häffner, S. and Hague, J.D. and Hahn, J. and Hampf, D. and Harris, J. and Heinz, S. and Heinzelmann, G. and Henri, G. and Hermann, G. and Hillert, A. and Hinton, J.A. and Hofmann, W. and Hofverberg, P. and Holler, M. and Horns, D. and Jacholkowska, A. and Jahn, C. and Jamrozy, M. and Jung, I. and Kastendieck, M.A. and Katarzyński, K. and Katz, U. and Kaufmann, S. and Khélifi, B. and Klochkov, D. and Kluźniak, W. and Kneiske, T. and Komin, Nu. and Kosack, K. and Kossakowski, R. and Krayzel, F. and Laffon, H. and Lamanna, G. and Lenain, J.-P. and Lennarz, D. and Lohse, T. and Lopatin, A. and Lu, C.-C. and Marandon, V. and Marcowith, A. and Masbou, J. and Maurin, G. and Maxted, N. and Mayer, M. and McComb, T.J.L. and Medina, M.C. and Méhault, J. and Menzler, U. and Moderski, R. and Mohamed, M. and Moulin, E. and Naumann, C.L. and Naumann-Godo, M. and de Naurois, M. and Nedbal, D. and Nguyen, N. and Niemiec, J. and Nolan, S.J. and Ohm, S. and de Oña Wilhelmi, E. and Opitz, B. and Ostrowski, M. and Oya, I. and Panter, M. and Parsons, D. and Paz Arribas, M. and Pekeur, N.W. and Pelletier, G. and Perez, J. and Petrucci, P.-O. and Peyaud, B. and Pita, S. and Pühlhofer, G. and Punch, M. and Quirrenbach, A. and Raue, M. and Reimer, A. and Reimer, O. and Renaud, M. and de los Reyes, R. and Rieger, F. and Ripken, J. and Rob, L. and Rosier-Lees, S. and Rowell, G. and Rudak, B. and Rulten, C.B. and Sahakian, V. and Sanchez, D.A. and Santangelo, A. and Schlickeiser, R. and Schulz, A. and Schwanke, U. and Schwarzburg, S. and Schwemmer, S. and Sheidaei, F. and Skilton, J.L. and Sol, H. and Spengler, G. and Stawarz, Ł. and Steenkamp, R. and Stegmann, C. and Stinzing, F. and Stycz, K. and Sushch, I. and Szostek, A. and Tavernet, J.-P. and Terrier, R. and Tluczykont, M. and Valerius, K. and van Eldik, C. and Vasileiadis, G. and Venter, C. and Viana, A. and Vincent, P. and Völk, H.J. and Volpe, F. and Vorobiov, S. and Vorster, M. and Wagner, S.J. and Ward, M. and White, R. and Wierzcholska, A. and Wouters, D. and Zacharias, M. and Zajczyk, A. and Zdziarski, A.A. and Zech, A. and Zechlin, H.-S. (2013) 'Measurement of the extragalactic background light imprint on the spectra of the brightest blazars observed with H.E.S.S.', Astronomy and astrophysics., 550 . A4.
The extragalactic background light (EBL) is the diffuse radiation with the second highest energy density in the Universe after the cosmic microwave background. The aim of this study is the measurement of the imprint of the EBL opacity to γ-rays on the spectra of the brightest extragalactic sources detected with the High Energy Stereoscopic System (H.E.S.S.). The originality of the method lies in the joint fit of the EBL optical depth and of the intrinsic spectra of the sources, assuming intrinsic smoothness. Analysis of a total of ~105γ-ray events enables the detection of an EBL signature at the 8.8σ level and constitutes the first measurement of the EBL optical depth using very-high energy (E > 100 GeV) γ-rays. The EBL flux density is constrained over almost two decades of wavelengths [0.30 μm, 17 μm] and the peak value at 1.4 μm is derived as λFλ = 15 ± 2stat ± 3sys nW m-2 sr-1.
|Keywords:||Gamma rays: galaxies, Cosmic background radiation, BL Lacertae objects: general.|
|Full text:||(VoR) Version of Record|
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|Publisher Web site:||http://dx.doi.org/10.1051/0004-6361/201220355|
|Publisher statement:||Reproduced with permission from Astronomy & Astrophysics, © ESO|
|Date accepted:||No date available|
|Date deposited:||15 July 2014|
|Date of first online publication:||February 2013|
|Date first made open access:||No date available|
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