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IDM2008 - Identification of Dark Matter 2008
IDM2008 - Identification of Dark Matter 2008
18-22 August 2008 AlbaNova
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Dark Matter Annihilation in the light of EGRET, HEAT, WMAP, INTEGRAL and ROSAT (15'+5')
 
The excess of diffuse galactic gamma rays above 1 GeV, as observed by the 
EGRET
telescope on the NASA Compton Gamma Ray Observatory,  shows all the key 
features from
Dark Matter (DM) annihilation:

1) the energy spectrum of the excess is the same in all sky directions and is
consistent with the   gamma rays expected for the  annihilation of  WIMPs with 
a 
mass   between 50-100 GeV;
2) the intensity distribution of the excess in the sky is used to determine the 
halo
profile, which was found to correspond to the usual profile from N-body 
simulations
with additional substructure in the form of two doughnut-shaped  structures  at 
radii
of 4 and 13 kpc;
3) recent N-body similations of the tidal disruption of the Canis Major dwarf 
galaxy
show that it is a perfect progenitor of the ringlike Monoceros tidal stream of 
stars
at 13 kpc with ring parameters in excellent agreement with the EGRET data;
4) the mass of the outer ring is so large, that its gravitational effects influence
both the gas flaring and the rotation curve of the Milky Way. Both effects are
clearly observed in agreement with the DMA interpretation of the EGRET 
excess;

Although the EGRET excess of gamma rays provides an intriguing hint for DMA, 
its
connection to the search for signals in antimatter particles is hampered by the
propagation model uncertainties, which determine the local fluxes of charged 
species
for a given source distribution. In the standard propagation models there is no
preferred propagation direction. In such models the Galaxy acts as a large 
storage
box for charged particles, thus leading to a strong enhancement of the particle
fluxes from the halo.
However, present data from INTEGRAL and ROSAT strongly suggest that 
convection
dominates over diffusion at low energies and in the source region, implying that
particles produced by DMA in the halo have little probability to arrive at the 
detector.
We present an anisotropic convection-dominated model for Cosmic Ray 
transport and
show that the EGRET gamma ray excess, the HEAT positron excess, the 
INTEGRAL positron
annihilation signal, the PAMELA antiproton fluxes and the WMAP-haze are 
consistent
with each other in such models.
 
Id: 413
Place: AlbaNova
Room: Oskar Klein auditorium
Starting date:
18-Aug-2008   14:25
Duration: 20'
Contribution type: Talk
Primary Authors: GEBAUER, Iris (Karlsruhe University)
Co-Authors: Prof. DE BOER, Wim (Karlsruhe University)
Dr. ZHUKOV, Valery (Karlsruhe University)
Presenters: GEBAUER, Iris
Material: slide Slides
 
Included in session: Indirect searches - gammas
Included in track: Indirect searches - gammas
 

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