ATIC, PAMELA, HESS, Fermi and nearby Dark Matter subhalos

Abstract

We study the local flux of electrons and positrons from annihilating Dark Matter (DM), and investigate how its spectrum depends on the choice of DM model and inhomogeneities in the DM distribution. Below a cutoff energy, the flux is expected to have a universal power-law form with an index n ~ -2. The cutoff energy and the behavior of the flux near the cutoff is model dependent. The dependence on the DM host halo profile may be significant at energies E < 100 GeV and leads to softening of the flux, n < -2. There may be additional features at high energies due to the presence of local clumps of DM, especially for models in which the Sommerfeld effect boosts subhalo luminosities. In general, the flux from a nearby clump gives rise to a harder spectrum of electrons and positrons, with an index n > -2. Using the Via Lactea II simulation, we estimate the probability of such subhalo effects in a generic Sommerfeld-enhanced model to be at least 4%, and possibly as high as 15% if subhalos below the simulation's resolution limit are accounted for. We discuss the consequences of these results for the interpretation of the ATIC, PAMELA, HESS, and Fermi data, as well as for future experiments.

v1: 15 pages, 7 figures; v2: 16 pages, 8 figures, title changed, figures 3 and 5 corrected, Fermi-LAT and HESS data added; v3: minor changes, figure 8 corrected

References in corpus (23)

• Observation of an anomalous positron abundance in the cosmic radiation
• A Theory of Dark Matter
• Measurement of the Cosmic Ray e+ plus e- spectrum from 20 GeV to 1 TeV with the Fermi Large Area Telescope
• What mass are the smallest protohalos?
• Kinetic Mixing as the Origin of Light Dark Scales
• Pulsars versus Dark Matter Interpretation of ATIC/PAMELA
• Minimal Dark Matter predictions for galactic positrons, anti-protons, photons
• Dark matter interpretation of recent electron and positron data
• Upper Bound on the Dark Matter Total Annihilation Cross Section
• The survival and disruption of CDM micro-haloes: implications for direct and indirect detection experiments
• Dark Matter Signals from Cascade Annihilations
• High-energy electron observations by PPB-BETS flight in Antarctica
• High Energy Positrons and the WMAP Haze from Exciting Dark Matter
• The PAMELA and ATIC Excesses From a Nearby Clump of Neutralino Dark Matter
• Breaking the Dark Force
• Dark matter and pulsar signals for Fermi LAT, PAMELA, ATIC, HESS and WMAP data
• Fossil remnants of reionization in the halo of the Milky Way
• TeV Scale Singlet Dark Matter
• Cosmic ray lepton puzzle in the light of cosmological N-body simulations
• TASI 2008 Lectures on Dark Matter
• Prospects for Detecting Neutrino Signals from Annihilating/Decaying Dark Matter to Account for the PAMELA and ATIC results
• A new estimate of the Galactic interstellar radiation field between 0.1 microns and 1000 microns
• Cosmic Ray Positrons from Annihilations into a New, Heavy Lepton

Cited by in corpus (11)

• CMB Constraints on WIMP Annihilation: Energy Absorption During the Recombination Epoch
• Pulsars versus Dark Matter Interpretation of ATIC/PAMELA
• Dark matter interpretation of recent electron and positron data
• Indirect Dark Matter Detection Limits from the Ultra-Faint Milky Way Satellite Segue 1
• Extended MSSM Neutralinos as the Source of the PAMELA Positron Excess
• Systematic study of the uncertainties in fitting the cosmic positron data by AMS-02
• Electrons and Positrons in Cosmic Rays
• Overcoming Gamma Ray Constraints with Annihilating Dark Matter in Milky Way Subhalos
• On discrepancy between ATIC and Fermi data
• Classification of gamma-ray targets for velocity-dependent and subhalo-boosted dark-matter annihilation
• Analytical insight into dark matter subhalo boost factors for Sommerfeld-enhanced $s$- and $p$-wave $\gamma$-ray signals