Can galactic dark matter substructure contribute to the cosmic gamma-ray anisotropy?

Abstract

The annihilation of dark matter (DM) particles in the Milky Way can contribute to the diffuse gamma-ray background (DGRB). Due to the presence of substructures, this emission will appear anisotropic in a predictable way. We generate full-sky maps of the gamma-ray emission in galactic substructures from results of the high-resolution Via Lactea II N-body simulation of the Milky Way DM halo. We calculate the anisotropy pattern, taking into account different radial profiles of the DM distribution in substructures, cosmic variance, and the detection threshold, and compare it to the anisotropy in the DGRB observed by the Fermi Large Area Telescope (LAT). By comparing the upper limits on the DM self-annihilation cross-section, <$\sigma v$>, implied by the anisotropy to the intensity of the DGRB and detected sources in the LAT 2-yr Point Source Catalog, we find that galactic substructure cannot contribute to the anisotropies in the DGRB without strongly violating these observations. Our results challenge the perception that small-scale anisotropies in the DGRB can be used as a probe of DM annihilation in galactic subhaloes.

arXiv commentaccepted for publication in MNRAS

References in corpus (38)

• The Structure of Cold Dark Matter Halos
• HEALPix -- a Framework for High Resolution Discretization, and Fast Analysis of Data Distributed on the Sphere
• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• The Aquarius Project: the subhalos of galactic halos
• Fermi Large Area Telescope Second Source Catalog
• Fermi Large Area Telescope First Source Catalog
• DarkSUSY: Computing Supersymmetric Dark Matter Properties Numerically
• Clumps and streams in the local dark matter distribution
• The Spectrum of the Isotropic Diffuse Gamma-Ray Emission Derived From First-Year Fermi Large Area Telescope Data
• Dark Matter Constraints from Observations of 25 Milky Way Satellite Galaxies with the Fermi Large Area Telescope
• The dark matter density at the Sun's location
• Astrophysical and Dark Matter Interpretations of Extended Gamma-Ray Emission from the Galactic Center
• Quantifying the heart of darkness with GHALO - a multi-billion particle simulation of our galactic halo
• The flattening of the concentration-mass relation towards low halo masses and its implications for the annihilation signal boost
• The First Fermi-LAT Catalog of Sources Above 10 GeV
• Constraints on Dark Matter Annihilation in Clusters of Galaxies with the Fermi Large Area Telescope
• Dark matter subhalos and the dwarf satellites of the Milky Way
• The Dark Matter Annihilation Signal from Galactic Substructure: Predictions for GLAST
• Implications of High-Resolution Simulations on Indirect Dark Matter Searches
• Where will supersymmetric dark matter first be seen?
• Anisotropies in the diffuse gamma-ray background measured by the Fermi LAT
• Dark matter annihilation or unresolved astrophysical sources? Anisotropy probe of the origin of cosmic gamma-ray background
• Density Profiles of CDM Microhalos and their Implications for Annihilation Boost Factors
• Joint anisotropy and source count constraints on the contribution of blazars to the diffuse gamma-ray background
• Diffuse gamma-ray emission from galactic pulsars
• Constraints on the annihilation cross section of dark matter particles from anisotropies in the diffuse gamma-ray background measured with Fermi-LAT
• Stringent Constraints On The Dark Matter Annihilation Cross Section From Subhalo Searches With The Fermi Gamma-Ray Space Telescope
• Gamma-ray background anisotropy from galactic dark matter substructure
• Can Astrophysical Gamma Ray Sources Mimic Dark Matter Annihilation in Galactic Satellites?
• Characterization of Dark-Matter-induced anisotropies in the diffuse gamma-ray background
• Mapping dark matter in the gamma-ray sky with galaxy catalogs
• Resolving Small-Scale Dark Matter Structures Using Multi-Source Indirect Detection
• Extragalactic gamma-ray background radiation from dark matter annihilation
• Constraining dark matter annihilation with the isotropic $\gamma$-ray background: updated limits and future potential
• Fermi-LAT gamma-ray anisotropy and intensity explained by unresolved Radio-Loud Active Galactic Nuclei
• Dark Matter implications of Fermi-LAT measurement of anisotropies in the diffuse gamma-ray background
• Gamma-ray anisotropies from dark matter in the Milky Way: the role of the radial distribution
• The sensitivity of Cherenkov telescopes to dark matter and astrophysical anisotropies in the diffuse gamma-ray background

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• Dark matter substructure modelling and sensitivity of the Cherenkov Telescope Array to Galactic dark halos
• $\gamma$-ray and $\nu$ searches for dark matter subhalos in the Milky Way with a baryonic potential
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