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Karl Mannheim – ITPA Würzburg. Gamma rays from the Virgo and Coma clusters of galaxies Berlin CTA-Meeting, May 4-5, 2006. Clusters of Galaxies. Storage of (UHE) cosmic rays Supernova-driven winds Radiojets from Active Galactic Nuclei Acceleration of (UHE) cosmic rays
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Karl Mannheim – ITPA Würzburg Gamma rays from the Virgo and Coma clusters of galaxies Berlin CTA-Meeting, May 4-5, 2006
Clusters of Galaxies • Storage of (UHE) cosmic rays • Supernova-driven winds • Radiojets from Active Galactic Nuclei • Acceleration of (UHE) cosmic rays • Cluster merger shocks • Accretion shocks • Dynamical relaxation shocks • Dark matter annihilation • Largest mass concentrations • Small-scale clumps dominance: Sorting in dM/R2 • Galactic Center • Nearest halo clump (unidentified EGRET?) • Nearest rich clusters (Virgo, Coma, Perseus) • Nearest dwarf galaxies (Sagittarius, Draco)
Coma cluster Virgo cluster
Cosmic rays in nearby clusters of galaxies Pfrommer et al.: Cosmic ray propagation model fitted to radio and X-ray observations, employing hydrodynamical code for of intracluster medium (g-ray fluxes > 50 GeV)
Cosmic rays in Coma Völk et al.: Cosmic ray propagation Reimer et al. Cosmic ray propagation Berrington & Dermer: Cluster merger shock
M 87 / Virgo Cluster DarkSusy scan C=40 C=335 • Control astrophysical backgrounds: • AGN in M87 • CRp – interactions • MAGIC observations • have started in May 2005 Targeted observations seem promising with new – generation experiments
M87 SED (ICRC)
Structure Formation • ART Code (A. Klypin et al.) • 3 £ 1014 solar masses; 9 million particles („Virgo Cluster“) • (sub)structure down to 3 £ 107 solar masses: clumps! 2DM ds D. Elsaesser, S. Gottloeber, A. Khalathyan and M. Steinmetz
Summary Clusters are cutting-edge targets for current IACTs Rich potential for astrophysics, cosmology, and particle physics • Origin of UHE cosmic rays • Dark matter annihilation • Role of nonthermal plasma in structure formation … northern location prefered for a dedicated„cluster mission“with future CTAs…