HESS constraints on dark matter annihilations towards the sculptor and carina dwarf galaxies
2011 (English)In: Astroparticle physics, ISSN 0927-6505, E-ISSN 1873-2852, Vol. 34, no 8, 608-616 p.Article in journal (Refereed) Published
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 h and 14.811 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% CL 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)-10(-12) cm(-2) s(-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(3) s(-1) down to <sigma v > similar to 10(-2)2 cm(3) s(-1) 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.
Place, publisher, year, edition, pages
2011. Vol. 34, no 8, 608-616 p.
Gamma-rays: observations - Dwarf spheroidal galaxy, Dark matter, Sculptor, Carina, Sommerfeld enhancement, Internal Bremsstrahlung
IdentifiersURN: urn:nbn:se:su:diva-69464DOI: 10.1016/j.astropartphys.2010.12.006ISI: 000288930200004OAI: oai:DiVA.org:su-69464DiVA: diva2:476861
authorCount :1942012-01-122012-01-122012-01-12Bibliographically approved