A Search for a Dark Matter Annihilation Signal Toward the Canis Major Overdensity with H.E.S.S

• Published in: The Astrophysical journal Vol. 691; no. 1; pp. 175 - 181
• Main Authors: Aharonian, F, de Almeida, U. Barres, Behera, B, Bernlöhr, K, Borrel, V, Braun, I, Brion, E, Brucker, J, Brun, P, Bühler, R, Bulik, T, Büsching, I, Boutelier, T, Chadwick, P. M, Charbonnier, A, Chaves, R. C. G, Coignet, G, Dalton, M, Degrange, B, Dickinson, H. J, Djannati-Ataï, A, Domainko, W, Dubois, F, Dyks, J, Dyrda, M, Egberts, K, Emmanoulopoulos, D, Farnier, C, Feinstein, F, Fontaine, G, Gabici, S, Gallant, Y. A, Gérard, L, Glicenstein, J. F, Glück, B, Goret, P, Hauser, M, Heinz, S, Hinton, J. A, Hoffmann, A, Hofmann, W, Holleran, M, Hoppe, S, Horns, D, Katarzyński, K, Kaufmann, S, Kendziorra, E, Kerschhaggl, M, Khangulyan, D, Khélifi, B, Keogh, D, Komin, Nu, Lamanna, G, Lenain, J.-P, Lohse, T, Marandon, V, Marcowith, A, McComb, T. J. L, Moderski, R, Naumann-Godo, M, de Naurois, M, Nedbal, D, Nekrassov, D, Niemiec, J, Nolan, S. J, Ohm, S, Olive, J.-F, Orford, K. J, Ostrowski, M, Panter, M, Pedaletti, G, Pelletier, G, Petrucci, P.-O, Pühlhofer, G, Quirrenbach, A, Raue, M, Renaud, M, Rieger, F, Ripken, J, Rosier-Lees, S, Rulten, C. B, Ruppel, J, Sahakian, V, Santangelo, A, Schlickeiser, R, Schwanke, U, Schwarzburg, S, Shalchi, A, Skilton, J. L, Stawarz, L, Steenkamp, R, Tam, P. H, Tibolla, O, van Eldik, C, Venter, C, Vialle, J. P, Vivier, M, Völk, H. J, Wagner, S. J, Zech, A
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 20.01.2009; IOP
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; galaxies: dwarf; Gamma radiation; Dark matter; Dwarf galaxies; gamma rays: observations
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/691/1/175

A search for a dark matter (DM) annihilation signal into gamma -rays toward the direction of the Canis Major (CMa) overdensity is presented. The nature of CMa is still controversial and one scenario represents it as a dwarf galaxy, making it an interesting candidate for DM annihilation searches. A total of 9.6 hr of high-quality data were collected with the H.E.S.S. array of Imaging Atmospheric Cherenkov Telescopes, and no evidence for a very high energy gamma -ray signal is found. Upper limits on the CMa dwarf galaxy mass of the order of 109 M are derived at the 95% confidence level (CL) assuming neutralino masses in the range 500 GeV-10 TeV and relatively large annihilation cross sections. Constraints on the velocity-weighted annihilation cross section sigma v are calculated for specific weakly interacting massive-particle scenarios, using a Navarro-Frenk-White model for the DM halo profile and taking advantage of numerical simulations of hierarchical structure formation. Assuming a total halo mass of 3 X 108 M , 95% CL exclusion limits of the order of 5 X 10 -24 cm3 s -1 are reached in the 500 GeV-10 TeV DM particle mass interval.