Ref HAL: in2p3-00188227_v1
Ref Arxiv: 0711.2369
DOI: 10.1016/j.astropartphys.2007.11.007
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
81 citations
Résumé:

Observations of the Sagittarius dwarf spheroidal (Sgr dSph) galaxy were carried out with the H.E.S.S. array of four imaging air Cherenkov telescopes in June 2006. A total of 11 hours of high quality data are available after data selection. There is no evidence for a very high energy gamma-ray signal above the energy threshold at the target position. A 95% C.L. flux limit of 3.6 x 10-12 cm-2s-1 above 250 GeV has been derived. Constraints on the velocity-weighted cross section are calculated in the framework of Dark Matter particle annihilation using realistic models for the Dark Matter halo profile of Sagittarius dwarf galaxy. Two different models have been investigated encompassing a large class of halo types. A 95% C.L. exclusion limit on of the order of 2 x 10-25 cm3s-1 is obtained for a core profile in the 100 GeV - 1 TeV neutralino mass range.

Commentaires: 21 pages, 4 figures, 2 tables; Erratum Astroparticle Physics 33:274-275, 2010; doi:10.1016/j.astropartphys.2010.01.007

Ref HAL: in2p3-00148883_v1
Ref Arxiv: 0704.2738
DOI: 10.1016/j.asr.2007.03.045
Ref. & Cit.: NASA ADS
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1 citation
Résumé:

The Gamma-Ray Large Area Space Telescope (GLAST), scheduled to be launched in fall 2007, is the next generation satellite for high-energy gamma-ray astronomy. The Large Area Telescope (LAT), GLAST main instrument, with a wide field of view (> 2 sr), a large effective area (> 8000 cm^2 at 1 GeV) and 20 MeV - 300 GeV energy range, will provide excellent high energy gamma-ray observations for Dark Matter searches. In this paper we examine the potential of the LAT to detect gamma-rays coming from WIMPS annihilation in the context of supersymmetry. As an example, two search regions are investigated: the galactic center and the galactic satellites.

Commentaires: Comment: 6 pages, 3 figures, 36th COSPAR proceeding accepted for publication in "Advances in Space Research"

Ref HAL: hal-00281841_v1
DOI: 10.1063/1.2757298
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Résumé:

We will describe the prospects for detecting gamma-rays from WIMP's annihilation in the Galactic Center and we compare this search with the possibilities at LHC and with space antimatter experiments like PAMELA.

Ref HAL: in2p3-00113422_v1
Ref Arxiv: astro-ph/0608247
DOI: 10.1051/0004-6361:20065884
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
14 citations
Résumé:

We have measured the gamma-ray fluxes of the blazars Mrk 421 and Mrk 501 in the energy range between 50 and 350 GeV (1.2 to 8.3 x 10^25 Hz). The detector, called CELESTE, used first 40, then 53 heliostats of the former solar facility "Themis" in the French Pyrenees to collect Cherenkov light generated in atmospheric particle cascades. The signal from Mrk 421 is often strong. We compare its flux with previously published multi-wavelength studies and infer that we are straddling the high energy peak of the spectral energy distribution. The signal from Mrk 501 in 2000 was weak (3.4 sigma). We obtain an upper limit on the flux from 1ES 1426+428 of less than half that of the Crab flux near 100 GeV. The data analysis and understanding of systematic biases have improved compared to previous work, increasing the detector's sensitivity.

Commentaires: 15 pages, 14 figures, accepted by A&A (July 2006) August 19 -- corrected error in author list

Ref HAL: in2p3-00026029_v1
DOI: 10.1016/j.nima.2005.12.211
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10 citations
Résumé:

The CsI calorimeter of the Gamma-Ray Large-Area Space Telescope (GLAST) will be calibrated in flight with cosmic-ray heavy ions. In order to determine the response of the calorimeter to relativistic heavy ions lighter than Fe, an experiment was carried out at the GSI heavy ion facility using the Fragment Separator (FRS). The measured response exhibits an unexpected feature for light ions, opposite to that observed at low incident energy: for a given deposited energy, the observed signal is greater for these ions than for protons (or more generally Z=1 minimum ionizing particles). Pulse shapes are found to be almost identical for carbon ions and Z=1 particles, with a significant slow scintillation component, which constitutes another departure from the low-energy behavior. Data on the energy resolution for the individual CsI crystals and on the loss of ions due to nuclear reactions in the calorimeter are also presented.

Commentaires: Publication commune GLAST et NEX

Ref HAL: in2p3-00109798_v1
Ref Arxiv: astro-ph/0601298
DOI: 10.1051/0004-6361:20054340
Ref. & Cit.: NASA ADS
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13 citations
Résumé:

If dark matter is made of neutralinos, annihilation of such Majorana particles should produce high energy cosmic rays, especially in galaxy halo high density regions like galaxy centres. M 31 (Andromeda) is our nearest neighbour spiral galaxy, and both its high mass and its low distance make it a source of interest for the indirect search for dark matter through $\gamma$-ray detection. The ground based atmospheric Cherenkov telescope CELESTE observed M 31 from 2001 to 2003, in the mostly unexplored energy range 50-500 GeV. These observations provide an upper limit on the flux above 50 GeV around $10^{-10}~\rm {cm}^{-2}\,\rm {s}^{-1}$ in the frame of supersymmetric dark matter, and more generally on any gamma emission from M 31.

Ref HAL: in2p3-00024566_v1
Ref Arxiv: astro-ph/0508349
DOI: 10.1103/PhysRevD.74.023518
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
9 citations
Résumé:

The detection of non-baryonic dark matter through its gamma-ray annihilation in the centre of our galaxy has been studied. The gamma fluxes according to different models have been simulated and compared to those expected to be observed with the Alpha Magnetic Spectrometer (AMS), during a long-term mission on board of the International Space Station. Under the assumption that the dark matter halo is composed of the lightest, stable supersymmetric particle, the neutralino, the results of the simulations in the framework of mSUGRA models, show that with a cuspy dark matter halo or a clumpy halo, the annihilation gamma-ray signal would be detected by AMS. More optimistic perspectives are obtained with the Anomaly Mediated Supersymmetry Breaking (AMSB) model. The latter leads also to a cosmologically important 6Li abundance. Finally, the discovery potential for the massive Kaluza-Klein dark matter candidates has been evaluated and their detection looks feasible.

Commentaires: 15 pages, 7 figures - AMS