23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 1 DarK Matter Annihilation In Clumpy Halos Collaboration with: Dominik Elsässer Acknowledgements: Matthias Steinmetz et al. (AIP Potsdam) ART code N-body simulations Joakim Edsjö (ANI Stockholm) DARKSUSY Stefan Hofmann (PI Toronto) Transfer function for WIMPs Tanja Kneiske (U Adelaide) EGB due to blazars Olaf Reimer (U Stanford) EGB from EGRET Aldo Morselli (INFN Roma) Multi-messenger
25
Embed
23.09.2006Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 20061 DarK Matter Annihilation In Clumpy Halos DarK Matter Annihilation.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 1
DarK Matter AnnihilationIn Clumpy Halos
DarK Matter AnnihilationIn Clumpy Halos
Collaboration with:
Dominik Elsässer
Acknowledgements:
Matthias Steinmetz et al. (AIP Potsdam) ART code N-body simulations Joakim Edsjö (ANI Stockholm) DARKSUSY Stefan Hofmann (PI Toronto) Transfer function for WIMPs Tanja Kneiske (U Adelaide) EGB due to blazars Olaf Reimer (U Stanford) EGB from EGRET Aldo Morselli (INFN Roma) Multi-messenger
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 2
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 4
DMA Folklore:II. Lee-Weinberg Criterion
DMA Folklore:II. Lee-Weinberg Criterion
Thermal history of Universe WIMPs (A~pb, m~0.1-1TeV) freeze out
at CDM density CDM~<Av>-1
Weakly interacting massive particles at ~200 GeV are generic cold dark
matter
Turner 1992
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 5
DMA Folklore:III. Neutralino as WIMP
DMA Folklore:III. Neutralino as WIMP
Lightest stable particle in R-parity conserving supersymmetry (neutralino): color singlet at
electroweak scale with m ~ 2-1/4GF-1/2 = 246 GeV
Long-believed
smoking gun!
but…
GLAST brochureGoebel 2004
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 6
DMA Folklore:IV. Secondary gamma rays from
High density regions
DMA Folklore:IV. Secondary gamma rays from
High density regions
Clumpy dark matter halo
Numerical limitation ~ 106 M
Stoehr et al. 2003
2
Attractor in nonlinear simulations: NFW profile (=1)
Galaxy cluster Abell 85: simulation vs. observation
Cu
sp
2
Durett et al. 2006
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 7
DMA Folklore:V. Galactic Center shows
Too hard spectrum
DMA Folklore:V. Galactic Center shows
Too hard spectrum
2
MAGIC/HESS observe SgrA* as steady source with hard power law above ~100 GeV J. Albert et al., ApJ Letters 638, L101 (2006)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 8
DMA Folklore:VI. Resume
DMA Folklore:VI. Resume
• Smoking-gun line feature at 100 GeV – 1 TeV not seen from Galactic Center (neither from M87)- Loop-suppressed or Z flux actually expected- Continuum flux from bb or WW peaks at 5 - 50 GeV- Relevant energy range currently inaccessible - Will open up with GLAST, HESS-II, and MAGIC-II
• Contribution to extragalactic background as inferred from EGRET data up to ~100 GeV- Expected to be small (Ullio et al. 2002; Ando 2005)- Extragalactic background: power law (Sreekumar et al. 98)- Galactic halo component of unknown origin with possible DMA
connection (Dixon et al. 98, de Boer et al. 2003)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 9
New Twist:I. Extragalactic gamma ray
Background from EGRET
New Twist:I. Extragalactic gamma ray
Background from EGRET
• Improved foreground model (GALPROP) removes enigmatic Galactic halo component and leads to new EGB spectrum (Strong, Moskalenko, and Reimer 2004)• EGB shows excess above 1 GeV (from power law dN/dE~E-2.33)
Blazars
IACT sensitivity: ~1000 high-
peaked blazars
expected
~50
13 known VHE blazars
as of 2006 (E
CRC 2006)
EGRET >100 MeV
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 10
Example of new type of high-peaked blazars which contribute to the EGB
Example of new type of high-peaked blazars which contribute to the EGB
New HBL at high redshift z=0.182 discovered at 100 GeV (Albert et al., 2006, ApJ Lett. 642, L119)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 11
Extragalactic Particle Accelerators – High Peaked BL Lacertae ObjectsExtragalactic Particle Accelerators – High Peaked BL Lacertae Objectspublished detections
•Discovery fraction of X-ray bright high-peaked blazars
(MAGIC 20h / source) ~ 30%
•200 high-peaked blazars extrapolated from X-ray catalogues / 3
~ 70 consistent with =2.33 extrapolation of sub-GeV EGB
•Positions of >10 GeV photons poorly correlated with positions
of known blazars (Thompson & Gehrels 2002)
•Thus: strong cosmological source of >GeV photons needed
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 12
Extragalactic gamma ray background contribution from HBLs based on the X-ray luminosity function of Beckmann (2003)
EGRET-type blazars
HBLs
Kneiske & Mannheim, ApJ (2006) submitted
Excess in EGB still remains!
Kneiske & Mannheim (2006)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 13
New Twist:II. Halo Substructure
New Twist:II. Halo Substructure
• Power spectra of SUSY-CDM (Green, Hofmann, & Schwarz 2004)
• Small scale DM clumps down to 10-6 Mat a scale of 0.02 pc
• Collisional damping and free streaming smear out inhomogeneities at still smaller scales
• Full range of structures 10-6 M– 1015 M not resolvable with
current computing resources (Diemand, Moore, & Stadel 2005)
Large boost factor for DMA emission (~2ds)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 14
New Twist:III. Cusp removal
New Twist:III. Cusp removal
Cusps can be destroyed by star formation feedback in high-z dwarfs (building blocks of galaxies)
Small scale clumps may also be destroyed by tidal interactions with the gaseous disks (Silk et al.)
DMA signal of galaxy cores much weaker than signal from cluster cores
Dwarfs
Giants, Clusters
Mashenko et al., Nature 442, 539 (2006)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 15
New Twist:IV. Other issues relevant for DMA
New Twist:IV. Other issues relevant for DMA
•Co-annihilation relaxes relation between A and DM (Baltz et al. 2006)•Anisotropy due to local clumps in DM halo (Elsässer & Mannheim 2004, Ando & Komatsu 2006) possible „smoking gun“•Problems with direct detection outside of clump•Detection of clumps from galactic halo with GLAST challenging (Pieri, Branchini, & Hofmann 2006)•Spikes around IMBHs (Bertone et al. 2005)•Positron excess measured by HEAT may be a hint for high-mass DMA (Edsjo 2002) •Synchrotron photon excess measured by WMAP („haze“) can be consistently explained by DMA (Finkbeiner 2004)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 16
Consistent Model:I. DMA Model for EGB above 1 GeV
Consistent Model:I. DMA Model for EGB above 1 GeV
Elsässer & Mannheim, PRL (2005)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 17
Consistent Model:II. Galactic Center
Consistent Model:II. Galactic Center
Consistent with EGRET/HESS/MAGIC non-detection due to energy gap!Cf. Ando (PRL 2005): (i) fluxes for 100 GeV and 1 TeV WIMPs avoiding the energy gap (ii) no clumping
Other consistency checks:
Direct detection
Radio background
Diffuse gal. gamma rays
Antiprotons/Positrons
WMAP foreground
Muon magnetic moment
Relic density
=10-3sr
Severe problems for DMA identification:(i) cusp depletion(ii) clump disruption(iii) stellar-origin source confusion
Radial profileof signal strength
X – Ray image (Chandra)
Follow up:I. Galactic Center ( HESS-II, GLAST)
Follow up:I. Galactic Center ( HESS-II, GLAST)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 19
Follow-up:II. Center of Virgo Cluster
(MAGIC-II, GLAST)
Follow-up:II. Center of Virgo Cluster
(MAGIC-II, GLAST)
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 20
M87 – Center of Virgo ClusterMAGIC Key Project
M 87 / Virgo Cluster
C=40
C=335
Targeted observations seem promising with new – generation experiments
DarkSusy scan
Control astrophysical backgrounds:-AGN in M87-CRp – interactions-MAGIC observations have started in May 2005
Gamma rays from the Dark Matter halo of M87
• ART Code (A. Klypin et al.)
• 3 1014 solar masses; 9 million particles („Virgo Cluster“)
• (sub)structure down to 3 107 solar masses
D. Elsaesser, S. Gottloeber, A. Khalathyan and M. Steinmetz
Gamma ray production ratedepends onthe line of sight integral
2DM ds
Clumping should lead to a signal detectableby MAGIC
M87 Spectral Energy Distribution
(ICRC)
2006
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 24
Gold-plated DMA signature in M87 at ~50 GeV: (i) Steady, soft spectrum (ii) clumpy morphology in FOV
Gold-plated DMA signature in M87 at ~50 GeV: (i) Steady, soft spectrum (ii) clumpy morphology in FOV
2nd telescope MAGIC-II in construction: improved clone of MAGIC
Stereo: improvement in terms of flux sensitivity, energy reconstruction and angular resolution
stereo
23.09.2006 Karl Mannheim: Dark Matter Annihilation in Clumpy Halos / DESY Theory Workshop 2006 25
SummarySummary
Clumpy structure of DM halos (12 orders of magnitude below current numerical simulations) boosts DMA rate
Neutralino with a mass of ~520 GeV and <Av>~3 10-26cm3s-1 provides consistent model for EGB above GeV energies
Confirmation with next generation of gamma ray observatories feasible (GLAST, HESS-II, MAGIC-II)
Investigate LHC signatures for neutralinos which can successfully match the constraints of the model (astrophysical scenario largely insensitive to detailed SUSY parameters)