H.E.S.S. constraints on Dark Matter annihilations towards the Sculptor and Carina Dwarf Galaxies

A. Abramowski , Fabio Acero (1) , F. Aharonian , A. G. Akhperjanian , G. Anton , A. Barnacka , U. Barres de Almeida , A. R. Bazer-Bachi (2) , Y. Becherini (3) , J. Becker , B. Behera , K. Bernlöhr , A. Bochow , C. Boisson (4) , J. Bolmont (5) , P. Bordas , V. Borrel (2) , J. Brucker , F. Brun (5) , P. Brun (6) , T. Bulik , I. Büsching , S. Carrigan , S. Casanova , M. Cerruti (4) , P. M. Chadwick , A. Charbonnier (5) , R. C. G. Chaves , A. Cheesebrough , L. -M. Chounet (7) , A. C. Clapson , G. Coignet (8) , J. Conrad , 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 (10) , J. Dyks , M. Dyrda , K. Egberts , P. Eger , P. Espigat (3) , L. Fallon , C. Farnier (1) , S. Fegan (7) , F. Feinstein (1) , M. V. Fernandes , A. Fiasson (8) , A. Frster , G. Fontaine (7) , M. Füssling , Y. A. Gallant (1) , H. Gast , L. Gérard (3) , D. Gerbig , B. Giebels (7) , J. F. Glicenstein (6) , B. Glück , P. Goret (6) , D. Göring , J. D. Hague , D. Hampf , M. Hauser , S. Heinz , G. Heinzelmann , G. Henri (10) , G. Hermann , J. A. Hinton , A. Hoffmann , W. Hofmann , P. Hofverberg , D. Horns , A. Jacholkowska (5) , O. C. de Jager , C. Jahn , M. Jamrozy , I. Jung , M. A. Kastendieck , K. Katarzyński , U. Katz , S. Kaufmann , D. Keogh , M. Kerschhaggl , D. Khangulyan , B. Khélifi (7) , D. Klochkov , W. Kluźniak , T. Kneiske , Nu. Komin (8) , K. Kosack (6) , R. Kossakowski (8) , H. Laffon , G. Lamanna (8) , D. Lennarz , T. Lohse , A. Lopatin , C. -C. Lu , V. Marandon (3) , A. Marcowith (1) , Julien Masbou (8) , D. Maurin (5) , N. Maxted , T. J. L. Mccomb , M. C. Medina (4) , J. Méhault (1) , R. Moderski , Emmanuel Moulin (6) , C. L. Naumann , M. Naumann-Godo , M. de Naurois (5) , D. Nedbal , D. Nekrassov , N. Nguyen , B. Nicholas , J. Niemiec , S. J. Nolan , S. Ohm , J-F. Olive (2) , E. de Oña Wilhelmi , B. Opitz , M. Ostrowski , M. Panter , M. Paz Arribas , G. Pedaletti1 , G. Pelletier (10) , P. -O. Petrucci (10) , S. Pita (3) , G. Pühlhofer , M. Punch (3) , A. Quirrenbach , M. Raue , S. M. Rayner , A. Reimer , O. Reimer , M. Renaud (3) , R. de Los Reyes , F. Rieger , J. Ripken , L. Rob , S. Rosier-Lees (8) , G. Rowell , B. Rudak , C. B. Rulten , J. Ruppel , F. Ryde , V. Sahakian , A. Santangelo , R. Schlickeiser , F. M. Schöck , A. Schönwald , U. Schwanke , S. Schwarzburg , S. Schwemmer , A. Shalchi , M. Sikora , J. L. Skilton , H. Sol (4) , G. Spengler , Ł. Stawarz , R. Steenkamp , C. Stegmann , F. Stinzing , I. Sushch , A. Szostek (10) , J. -P. Tavernet (5) , R. Terrier (3) , O. Tibolla , M. Tluczykont , K. Valerius , C. van Eldik , G. Vasileiadis (1) , C. Venter , J. P. Vialle (8) , A. Viana , P. Vincent (5) , M. Vivier (6) , H. J. Völk , F. Volpe , S. Vorobiov (1) , M. Vorster , S. J. Wagner , M. Ward , A. Wierzcholska , A. Zajczyk , A. A. Zdziarski , A. Zech (4) , H. -S. Zechlin

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

The Sculptor and Carina Dwarf spheroidal galaxies were observed with the H.E.S.S. Cherenkov telescope array between January 2008 and December 2009. The data sets consist of a total of 11.8 and 14.8 hours of high quality data, respectively. No gamma-ray signal was detected at the nominal positions of these galaxies above 220 GeV and 320 GeV, respectively. Upper limits on the gamma-ray fluxes at 95% C.L. assuming two forms for the spectral energy distribution (a power law shape and one derived from dark matter annihilation) are obtained at the level of 10^-13 to 10^-12 cm^-2s^-1 in the TeV range. Constraints on the velocity weighted dark matter particle annihilation cross section for both Sculptor and Carina dwarf galaxies range from <\sigma v> ~ 10^-21 cm^3s^-1 down to <\sigma v> ~ 10^-22 cm^3s^-1 depending on the dark matter halo model used. Possible enhancements of the gamma-ray flux are studied: the Sommerfeld effect, which is found to exclude some dark matter particle masses, the internal Bremsstrahlung and clumps in the dark-matter halo distributions.

Domains: Physics [physics]; Astrophysics [astro-ph]; High Energy Astrophysical Phenomena [astro-ph.HE]; Sciences of the Universe [physics]; Astrophysics [astro-ph]; High Energy Astrophysical Phenomena [astro-ph.HE]

A. Abramowski, Fabio Acero, F. Aharonian, A. G. Akhperjanian, G. Anton, et al.. H.E.S.S. constraints on Dark Matter annihilations towards the Sculptor and Carina Dwarf Galaxies. Astroparticle Physics, 2011, 34, pp.608-616. ⟨10.1016/j.astropartphys.2010.12.006⟩. ⟨in2p3-00562644⟩