Cosmic ray lepton puzzle in the light of cosmological N-body simulations

Abstract

The PAMELA and ATIC collaborations have recently reported an excess in the cosmic ray positron and electron fluxes. These lepton anomalies might be related to cold dark matter (CDM) particles annihilating within a nearby dark matter clump. We outline regions of the parameter space for both the dark matter subhalo and particle model, where data from the different experiments are reproduced. We then confront this interpretation of the data with the results of the cosmological N-body simulation Via Lactea II. Having a sizable clump (Vmax = 9km/s) at a distance of only 1.2 kpc could explain the PAMELA excess, but such a configuration has a probability of only 0.37 percent. Reproducing also the ATIC bump would require a very large, nearby subhalo, which is extremely unlikely (p~3.10^-5). In either case, we predict Fermi will detect the gamma-ray emission from the subhalo. We conclude that under canonical assumptions, the cosmic ray lepton anomalies are unlikely to originate from a nearby CDM subhalo.

5 pages, 3 figures

References in corpus (9)

• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation
• Dark Matter and Collider Phenomenology of Universal Extra Dimensions
• Constraints on WIMP Dark Matter from the High Energy PAMELA $\bar{p}/p$ data
• The shapes, orientation, and alignment of Galactic dark matter subhalos
• The PAMELA and ATIC Excesses From a Nearby Clump of Neutralino Dark Matter
• Antiproton and Positron Signal Enhancement in Dark Matter Mini-Spikes Scenarios
• An optimum time-stepping scheme for N-body simulations
• Local dark matter clumps and the cosmic ray positron excess

Cited by in corpus (19)

• On possible interpretations of the high energy electron-positron spectrum measured by the Fermi Large Area Telescope
• Inverse Compton constraints on the Dark Matter e+e- excesses
• Galactic Substructure and Dark Matter Annihilation in the Milky Way Halo
• A new look at the cosmic ray positron fraction
• ATIC, PAMELA, HESS, Fermi and nearby Dark Matter subhalos
• Dark Matter Indirect Signatures
• Leptons from Dark Matter Annihilation in Milky Way Subhalos
• Systematic study of the uncertainties in fitting the cosmic positron data by AMS-02
• Searches for dark matter subhaloes with wide-field Cherenkov telescope surveys
• Black Holes in our Galactic Halo: Compatibility with FGST and PAMELA Data and Constraints on the First Stars
• Primordial Black Hole as a Source of the Boost Factor
• Electrons and Positrons in Cosmic Rays
• The PAMELA and Fermi signals from long-lived Kaluza-Klein dark matter
• Testing the dark matter subhalo hypothesis of the gamma-ray source 3FGL J2212.5+0703
• Higgsino dark matter model consistent with galactic cosmic ray data and possibility of discovery at LHC-7
• Overcoming Gamma Ray Constraints with Annihilating Dark Matter in Milky Way Subhalos
• On discrepancy between ATIC and Fermi data
• Cosmic ray backgrounds for dark matter indirect detection
• An observable electron-positron anisotropy cannot be generated by dark matter