Possible Indications of a Clumpy Dark Matter Halo

Abstract

We investigate if the gamma ray halo, for which recent evidence has been found in EGRET data, can be explained by neutralino annihilations in a clumpy halo. We find that the measured excess gamma ray flux can be explained through a moderate amount of clumping in the halo. Moreover, the required amount of clumping implies also a measureable excess of antiprotons at low energies, for which there is support from recent measurements by the BESS collaboration. The predicted antiproton fluxes resulting from neutralino annihilations in a clumpy halo are high enough to give an excess over cosmic-ray produced antiprotons also at moderately high energies (above a few GeV). This prediction, as well as that of one or two sharp gamma lines coming from annihilations into 2 gammas or Z gamma can be tested in upcoming space-borne experiments like AMS and GLAST.

5 pages, 3 eps-figures (included), LaTeX, uses RevTeX

References in corpus (3)

• EGRET Observations of the Extragalactic Gamma Ray Emission
• Big-bang Nucleosynthesis Enters the Precision Era
• The Alpha Magnetic Spectrometer (AMS): search for antimatter and dark matter on the International Space Station

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