HESS Collaboration, A. Abramowski, F. Acero, F. Aharonian, A. G. Akhperjanian, G. Anton, A. Balzer, A. Barnacka, U. Barres de Almeida, Y. Becherini, J. Becker, B. Behera, K. Bernlöhr, E. Birsin, J. Biteau, A. Bochow, C. Boisson, J. Bolmont, P. Bordas, J. Brucker, F. Brun, P. Brun, T. Bulik, I. Büsching, S. Carrigan, S. Casanova, M. Cerruti, P. M. Chadwick, A. Charbonnier, R. C. G. Chaves, A. Cheesebrough, A. C. Clapson, G. Coignet, G. Cologna, J. Conrad, M. Dalton, M. K. Daniel, I. D. Davids, B. Degrange, C. Deil, H. J. Dickinson, A. Djannati-Ataï, W. Domainko, L. O'C. Drury, G. Dubus, K. Dutson, J. Dyks, M. Dyrda, K. Egberts, P. Eger, P. Espigat, L. Fallon, C. Farnier, S. Fegan, F. Feinstein, M. V. Fernandes, A. Fiasson, G. Fontaine, A. Förster, M. Füßling, Y. A. Gallant, H. Gast, L. Gérard, D. Gerbig, B. Giebels, J. F. Glicenstein, B. Glück, P. Goret, D. Göring, S. Häffner, J. D. Hague, D. Hampf, M. Hauser, S. Heinz, G. Heinzelmann, G. Henri, G. Hermann, J. A. Hinton, A. Hoffmann, W. Hofmann, P. Hofverberg, M. Holler, D. Horns, A. Jacholkowska, O. C. de Jager, C. Jahn, M. Jamrozy, I. Jung, M. A. Kastendieck, K. Katarzyński, U. Katz, S. Kaufmann, D. Keogh, D. Khangulyan, B. Khélifi, D. Klochkov, W. Kluźniak, T. Kneiske, Nu. Komin, K. Kosack, R. Kossakowski, H. Laffon, G. Lamanna, D. Lennarz, T. Lohse, A. Lopatin, C. -C. Lu, V. Marandon, A. Marcowith, J. Masbou, D. Maurin, N. Maxted, M. Mayer, T. J. L. McComb, M. C. Medina, J. Méhault, R. Moderski, E. Moulin, C. L. Naumann, M. Naumann-Godo, M. de Naurois, D. Nedbal, D. Nekrassov, N. Nguyen, B. Nicholas, J. Niemiec, S. J. Nolan, S. Ohm, E. de Oña Wilhelmi, B. Opitz, M. Ostrowski, I. Oya, M. Panter, M. Paz Arribas, G. Pedaletti1, G. Pelletier, P. -O. Petrucci, S. Pita, G. Pühlhofer, M. Punch, A. Quirrenbach, M. Raue, S. M. Rayner, A. Reimer, O. Reimer, M. Renaud, R. de los Reyes, F. Rieger, J. Ripken, L. Rob, S. Rosier-Lees, G. Rowell, B. Rudak, C. B. Rulten, J. Ruppel, V. Sahakian, D. A. Sanchez, A. Santangelo, R. Schlickeiser, F. M. Schöck, A. Schulz, U. Schwanke, S. Schwarzburg, S. Schwemmer, F. Sheidaei, J. L. Skilton, H. Sol, G. Spengler, Ł. Stawarz, R. Steenkamp, C. Stegmann, F. Stinzing, K. Stycz, I. Sushch, A. Szostek, J. -P. Tavernet, R. Terrier, M. Tluczykont, K. Valerius, C. van Eldik, G. Vasileiadis, C. Venter, J. P. Vialle, A. Viana, P. Vincent, H. J. Völk, F. Volpe, S. Vorobiov, M. Vorster, S. J. Wagner, M. Ward, R. White, A. Wierzcholska, M. Zacharias, A. Zajczyk, A. A. Zdziarski, A. Zech, H. -S. Zechlin
The Fornax galaxy cluster was observed with the High Energy Stereoscopic
System (H.E.S.S.) for a total live time of 14.5 hours, searching for
very-high-energy (VHE, E>100 GeV) gamma-rays from dark matter (DM)
annihilation. No significant signal was found in searches for point-like and
extended emissions. Using several models of the DM density distribution, upper
limits on the DM velocity-weighted annihilation cross-section as a
function of the DM particle mass are derived. Constraints are derived for
different DM particle models, such as those arising from Kaluza-Klein and
supersymmetric models. Various annihilation final states are considered.
Possible enhancements of the DM annihilation gamma-ray flux, due to DM
substructures of the DM host halo, or from the Sommerfeld effect, are studied.
Additional gamma-ray contributions from internal bremsstrahlung and inverse
Compton radiation are also discussed. For a DM particle mass of 1 TeV, the
exclusion limits at 95% of confidence level reach values of ~
10^-23cm^3s^-1, depending on the DM particle model and halo properties.
Additional contribution from DM substructures can improve the upper limits on
<\sigma v> by more than two orders of magnitude. At masses around 4.5 TeV, the
enhancement by substructures and the Sommerfeld resonance effect results in a
velocity-weighted annihilation cross-section upper limit at the level of
<\sigma v> ~ 10^-26cm^3s^-1.
View original:
http://arxiv.org/abs/1202.5494
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