Author(s): Aharonian F., Bazer-Bachi A.R., Boisson C., Borrel V., Brion E., Boutelier T., Chounet L.-M., Coignet G., Degrange B., Djannati-Ataï A., Dubois F., Dubus G., Espigat P., Farnier C., Feinstein F., Fiasson A., Fontaine G., Gallant Y., Giebels B., Glicenstein J.F., Goret P., Henri G., Jacholkowska Agnieszka, Khélifi B., Komin Nukri, Lamanna G., Lenain J.-P., Martin J.M., Marcowith A., Vasileiadis G.
(Article) Published:
The Astrophysical Journal / The Astrophysical Journal Letters, vol. 691 p.175-181 (2009)
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Ref Arxiv: 0809.3894
DOI: 10.1088/0004-637X/691/1/175
Ref. & Cit.: NASA ADS
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Abstract:
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 hours of high quality data were collected with the H.E.S.S. array of Imaging Atmospheric Cherenkov Telescopes (IACTs) 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 10$^{9}$ M$_{\odot}$ are derived at the 95% C.L. 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 WIMP scenarios, using a NFW model for the DM halo profile and taking advantage of numerical simulations of hierarchical structure formation. 95% C.L. exclusion limits of the order of 5 $\times$ 10$^{-24}$ cm$^{3}$ s$^{-1}$ are reached in the 500 GeV - 10 TeV DM particle mass interval, assuming a total halo mass of 3 $\times$ 10$^{8}$ M$_{\odot}$.
Comments: Accepted for publication in ApJ