Gamma-ray and synchrotron emission from neutralino annihilation in the Large Magellanic Cloud

Abstract

We calculate the expected flux of gamma-ray and radio emission from the LMC due to neutralino annihilation. Using rotation curve data to probe the density profile and assuming a minimum disk, we describe the dark matter halo of the LMC using models predicted by N-body simulations. We consider a range of density profiles including the NFW profile, a modified NFW profile proposed by Hayashi et al.(2003) to account for the effects of tidal stripping, and an isothermal sphere with a core. We find that the gamma-ray flux expected from these models may be detectable by GLAST for a significant part of the neutralino parameter space. The prospects for existing and upcoming Atmospheric Cherenkov Telescopes are less optimistic, as unrealistically long exposures are required for detection. However, the effects of adiabatic compression due to the baryonic component may improve the chances for detection by ACTs. The maximum flux we predict is well below EGRET's measurements and thus EGRET does not constrain the parameter space. The expected synchrotron emission generally lies below the observed radio emission from the LMC in the frequency range of 19.7 to 8550 MHz. As long as <sigma v> <2x 10^-26 cm^3 s^-1 for a neutralino mass of 50 GeV, the observed radio emission is not primarily due to neutralinos and is consistent with the assumption that the main source is cosmic rays. We find that the predicted fluxes, obtained by integrating over the entire LMC, are not very strongly dependent on the inner slope of the halo profile, varying by less than an order of magnitude for the range of profiles we considered.

arXiv comment24 pages, 5 figures; detailed discussion of how the neutralino induced signals compare with the cosmic-ray induced ones was added. Main conclusions unchanged. Matches accepted version, to appear in Astroparticle Physics

References in corpus (29)

• The Structure of Cold Dark Matter Halos
• Supersymmetric Dark Matter
• Simulations of X-ray Clusters
• Resolving the Structure of Cold Dark Matter Halos
• Dark matter annihilation at the galactic center
• EGRET Observations of the Extragalactic Gamma Ray Emission
• New Understanding of Large Magellanic Cloud Structure, Dynamics and Orbit from Carbon Star Kinematics
• Observability of Gamma Rays from Dark Matter Neutralino Annihilations in the Milky Way Halo
• Galaxies in N-body simulations: overcoming the overmerging problem
• The Structural Evolution of Substructure
• Cosmological dark matter annihilations into gamma-rays - a closer look
• The Milky Way's satellite population in a LambdaCDM universe
• Cosmic Rays, Radio Halos and Non-Thermal X-ray Emission in Clusters of Galaxies
• Clumpy Neutralino Dark Matter
• Spectral Gamma-ray Signatures of Cosmological Dark Matter Annihilation
• The Clumpiness of Cold Dark Matter: Implications for the Annihilation Signal
• The surface brightness of dark matter: unique signatures of neutralino annihilation in the Galactic halo
• Astrophysical inputs on the SUSY dark matter annihilation detectability
• Detection of Neutralino Annihilation Photons from External Galaxies
• The Rotation Curve of the Large Magellanic Cloud and the Implications for Microlensing
• The Detectability of Neutralino Clumps via Atmospheric Cherenkov Telescopes
• Diffuse Gamma-Rays from Local Group Galaxies
• Particle Dark Matter Constraints from the Draco Dwarf Galaxy
• Neutralinos and the Origin of Radio Halos in Clusters of Galaxies
• Detecting WIMPs in the Microwave Sky
• The Cold Dark Matter crisis on galactic and subgalactic scales
• The Cangaroo-III Project
• Dark Bulge, Exponential Disk, and Massive Halo in the Large Magellanic Cloud
• Dark Matter Annihilations in the Large Magellanic Cloud

Cited by in corpus (29)

• Particle Dark Matter: Evidence, Candidates and Constraints
• A review of indirect searches for particle dark matter
• Where to find a dark matter sterile neutrino?
• Dark Matter Dynamics and Indirect Detection
• Dark Matter Annihilation in Substructures Revised
• Constraining DM properties with SPI
• Multi-wavelength signals of dark matter annihilations at the Galactic center
• Observations of the Sagittarius Dwarf galaxy by the H.E.S.S. experiment and search for a Dark Matter signal
• Photon spectra from WIMP annihilation
• Fitting formulae for photon spectra from WIMP annihilation
• Search for Gamma-ray Emission from Dark Matter Annihilation in the Large Magellanic Cloud with the Fermi Large Area Telescope
• The EMU view of the Large Magellanic Cloud: Troubles for sub-TeV WIMPs
• Radio constraints on dark matter annihilation in the galactic halo and its substructures
• Annihilation vs. Decay: Constraining dark matter properties from a gamma-ray detection
• The detectability of dark matter annihilation with Fermi using the anisotropy energy spectrum of the gamma-ray background
• Radio emission from dark matter annihilation in the Large Magellanic Cloud
• Re-Examining Astrophysical Constraints on the Dark Matter Model
• Updated galactic radio constraints on Dark Matter
• $\gamma$-ray flux from Dark Matter Annihilation in Galactic Caustics
• Searching for dark matter annihilation from individual halos: uncertainties, scatter and signal-to-noise ratios
• Searching for Dark Matter in Messier 33
• Analysing the radio flux density profile of the M31 galaxy: a possible dark matter interpretation
• Constraining annihilating dark matter by radio continuum spectrum of the Large Magellanic Cloud
• Testing the dark matter origin of the WMAP-Planck Haze with radio observations of Spiral Galaxies
• Complementarity of Gamma-ray and LHC Searches for Neutralino Dark Matter in the Focus Point Region
• Dark matter with photons
• Dark Matter constraints from Planck observations of the Galactic polarized synchrotron emission
• Dark matter constraints from an observation of dSphs and the LMC with the Baikal NT200
• Radio Signal by Galactic Dark Matter