Excess of EGRET Galactic Gamma Ray Data interpreted as Dark Matter Annihilation

Abstract

The diffuse galactic EGRET gamma ray data show a clear excess for energies above 1 GeV in comparison with the expectations from conventional galactic models. The excess is seen with the same spectrum in all sky directions, as expected for Dark Matter (DM) annihilation. This hypothesis is investigated in detail. The energy spectrum of the excess is used to limit the WIMP mass to the 50-100 GeV range, while the sky maps are used to determine the halo structure, which is consistent with a triaxial isothermal halo with additional enhancement of Dark Matter in the disc. The latter is strongly correlated with the ring of stars around our galaxy at a distance of 14 kpc, thought to originate from the tidal disruption of a dwarf galaxy. It is shown that this ring of DM with a mass of $\approx 2\cdot 10^{11}{M}_{\odot }$ causes the mysterious change of slope in the rotation curve at $R=1.1R_0$ and the large local surface density of the disc. The total mass of the halo is determined to be $3\cdot 10^{12}{M}_{\odot }$. A cuspy profile is definitely excluded to describe the gamma ray data. These signals of Dark Matter Annihilation are compatible with Supersymmetry for boost factors of 20 upwards and have a statistical significance of more than $10\sigma$ in comparison with the conventional galactic model. The latter combined with all features mentioned above provides an intriguing hint that the EGRET excess is indeed a signal from Dark Matter Annihilation.

arXiv comment24 pages, 9 figures, Contributed Paper to ICHEP04, Beijing v2.: Updated references, somewhat improved fits and some clarifications in text

References in corpus (30)

• Particle Dark Matter: Evidence, Candidates and Constraints
• Search for the Standard Model Higgs Boson at LEP
• Propagation of cosmic-ray nucleons in the Galaxy
• Non-Baryonic Dark Matter - Observational Evidence and Detection Methods
• SuSpect: a Fortran Code for the Supersymmetric and Higgs Particle Spectrum in the MSSM
• Diffuse continuum gamma rays from the Galaxy
• Diffuse Galactic continuum gamma rays. A model compatible with EGRET data and cosmic-ray measurements
• Internal and External Alignment of the Shapes and Angular Momenta of LCDM Halos
• The Kinematics, Orbit, and Survival of the Sagittarius Dwarf Spheroidal Galaxy
• Cosmological dark matter annihilations into gamma-rays - a closer look
• One Ring to Encompass them All: A giant stellar structure that surrounds the Galaxy
• Shapes and Alignments of Galaxy Cluster Halos
• The surface brightness of dark matter: unique signatures of neutralino annihilation in the Galactic halo
• Dark halo properties from rotation curves
• Grand Unified Theories and Supersymmetry in Particle Physics and Cosmology
• Global Electroweak Fits and Gauge Coupling Unification
• Mass Modeling of Disk Galaxies: Constraints, Degeneracies and Adiabatic Contraction
• Supersymmetric Dark Matter and the Extragalactic Gamma Ray Background
• The outer rotation curve of the Milky Way
• Gamma Rays from Neutralino Annihilation
• Mass of the Galaxy Inferred from Outer Rotation Curve
• FeynHiggsFast: a program for a fast calculation of masses and mixing angles in the Higgs Sector of the MSSM
• Improving the Angular Resolution of EGRET and New Limits on Supersymmetric Dark Matter Near the Galactic Center
• Indirect Evidence for Neutralinos as Dark Matter
• micrOMEGAs: recent developments
• Dark Matter in Galaxies: Observational overview
• Dark and luminous matter connections. Towards understanding galaxy evolution
• Disk Galaxy Rotation Curves in Triaxial CDM Halos
• The Galactic Halo and CDM
• Dark Matter Constraints from the Sagittarius Dwarf and Tail System

Cited by in corpus (14)

• Cold Dark Matter as Compact Composite Objects
• Extragalactic gamma-ray background radiation from dark matter annihilation
• TASI 2008 Lectures on Dark Matter
• Robust Gamma Ray Signature of WIMP Dark Matter
• Adiabatic compression and indirect detection of supersymmetric dark matter
• Supersymmetry on the Run: LHC and Dark Matter
• Dark matter and the LHC
• Predictions of the causal entropic principle for environmental conditions of the universe
• Dark matter and Colliders searches in the MSSM
• TASI 2008 lectures on Collider Signals II: E_T^missing signatures and the dark matter connection
• SUSY interpretation of the Egret GeV anomaly, Xenon-10 dark matter search limits and the LHC
• Indirect Evidence for WIMP Annihilation from Diffuse Galactic Gamma Rays
• SUSY: Theory Status in the Light of Experimental Constraints
• Dark matter searches and Colliders