Dark Matter and the CACTUS Gamma-Ray Excess from Draco

Abstract

The CACTUS atmospheric Cherenkov telescope collaboration recently reported a gamma-ray excess from the Draco dwarf spheroidal galaxy. Draco features a very low gas content and a large mass-to-light ratio, suggesting as a possible explanation annihilation of weakly interacting massive particles (WIMPs) in the Draco dark-matter halo. We show that with improved angular resolution, future measurements can determine whether the halo is cored or cuspy, as well as its scale radius. We find the relevant WIMP masses and annihilation cross sections and show that supersymmetric models can account for the required gamma-ray flux. The annihilation cross section range is found to be not compatible with a standard thermal relic dark-matter production. We compute for these supersymmetric models the resulting Draco gamma-ray flux in the GLAST energy range and the rates for direct neutralino detection and for the flux of neutrinos from neutralino annihilation in the Sun. We also discuss the possibility that the bulk of the signal detected by CACTUS comes from direct WIMP annihilation to two photons and point out that a decaying-dark-matter scenario for Draco is not compatible with the gamma-ray flux from the Galactic center and in the diffuse gamma-ray background.

24 pages, 10 figures; version accepted for publication in JCAP

References in corpus (40)

• First Year Wilkinson Microwave Anisotropy Probe (WMAP) Observations: Determination of Cosmological Parameters
• Particle Dark Matter: Evidence, Candidates and Constraints
• Supersymmetric Dark Matter
• Dwarf Galaxies of the Local Group
• The Structure of Dark Matter Haloes in Dwarf Galaxies
• Non-Baryonic Dark Matter - Observational Evidence and Detection Methods
• Resolving the Structure of Cold Dark Matter Halos
• Wino Cold Dark Matter from Anomaly-Mediated SUSY Breaking
• Observability of Gamma Rays from Dark Matter Neutralino Annihilations in the Milky Way Halo
• Dark Matter Scaling Relations
• Quintessence and the Relic Density of Neutralinos
• Dark Matter in Dwarf Spheroidals II: Observations and Modelling of Draco
• A "Baedecker" for the Dark Matter Annihilation Signal
• Kinematically Cold Populations at Large Radii in the Draco and Ursa Minor Dwarf Spheroidals
• Non-Thermal Production of WIMPs and the Sub-Galactic Structure of the Universe
• Non-thermal dark matter via Affleck-Dine baryogenesis and its detection possibility
• SUSY Dark Matter and Quintessence
• Neutralino annihilation into gamma-rays in the Milky Way and in external galaxies
• Higgsino and Wino Dark Matter from Q-ball Decay in Affleck-Dine Baryogenesis
• TeV gamma-rays and the largest masses and annihilation cross sections of neutralino dark matter
• Detection of Neutralino Annihilation Photons from External Galaxies
• First Clear Signature of an Extended Dark Matter Halo in the Draco Dwarf Spheroidal
• Low energy antideuterons: shedding light on dark matter
• Non-thermal Production of Neutralino Cold Dark Matter from Cosmic String Decays
• Quintessential Enhancement of Dark Matter Abundance
• The Role of Antimatter Searches in the Hunt for Supersymmetric Dark Matter
• TeV $\gamma$-radiation from Dark Matter annihilation in the Galactic center
• Supersymmetric Dark Matter and the Extragalactic Gamma Ray Background
• Particle Dark Matter Constraints from the Draco Dwarf Galaxy
• Search for Dark Matter with GLAST
• Nucleon scattering with higgsino and wino cold dark matter
• Have Atmospheric Cerenkov Telescopes Observed Dark Matter?
• Beryllium in Disk and Halo Stars -- Evidence for a Beryllium Dispersion in Old Stars
• Constraining global properties of the Draco dwarf spheroidal galaxy
• On Dark Matter Annihilation in the Local Group
• Improved Searches for HI in Three Dwarf Spheroidal Galaxies
• Gauge Mediated Supersymmetry Breaking and Multi-TeV Gamma-Rays from the Galactic Center
• Extended coannihilations from non universal sfermion masses
• Next generation of IACT arrays: scientific objectives versus energy domains
• Search for TeV Radiation from Selected Local Group Galaxies

Cited by in corpus (23)

• Dark Matter and Collider Phenomenology of Universal Extra Dimensions
• Neutrino Constraints on the Dark Matter Total Annihilation Cross Section
• Empirical Models for Dark Matter Halos. II. Inner profile slopes, dynamical profiles, and rho/sigma^3
• The Most Dark Matter Dominated Galaxies: Predicted Gamma-ray Signals from the Faintest Milky Way Dwarfs
• A Comprehensive Search for Dark Matter Annihilation in Dwarf Galaxies
• Detecting dark matter WIMPs in the Draco dwarf: a multi-wavelength perspective
• Indication of Gamma-ray Emission from the Newly Discovered Dwarf Galaxy Reticulum II
• The Effects of Dark Matter Decay and Annihilation on the High-Redshift 21 cm Background
• Indirect detection of light neutralino dark matter in the NMSSM
• Challenges in Detecting Gamma-Rays From Dark Matter Annihilations in the Galactic Center
• Hunting the lightest lightest neutralinos
• Substructure Boosts to Dark Matter Annihilation from Sommerfeld Enhancement
• Indirect Detection of Little Higgs Dark Matter
• Maximum Likelihood Fitting of Tidal Streams With Application to the Sagittarius Dwarf Tidal Tails
• Dark Matter annihilation in Draco: new considerations of the expected gamma flux
• Search for Gamma-rays from Dark Matter annihilations around Intermediate Mass Black Holes with the H.E.S.S. experiment
• The Shadow of Dark Matter
• Non-thermal X-rays from the Ophiuchus galaxy cluster and dark matter annihilation
• Distinguishing Supersymmetry From Universal Extra Dimensions or Little Higgs Models With Dark Matter Experiments
• Determining Supersymmetric Parameters With Dark Matter Experiments
• Dark Matter: the Connection with Gamma-Ray Astrophysics
• Radio-Frequency Searches for Dark Matter in Dwarf Galaxies
• Neutralino-neutralino annihilation to gammaZ in MSSM