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Indirect dark matter search with YBJ-AS Observatory. Outline Introduction Status of ground-based observations Data analysis with AS experiment Results 5. Conclusions. Wu hanrong on behalf of YBJ-ASg collaboration 2008.09.24 TeVPA-IV@IHEP. Gamma-ray flux from WIMP annihilation:.
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Indirect dark matter search with YBJ-AS Observatory Outline • Introduction • Status of ground-based observations • Data analysis with AS experiment • Results 5. Conclusions Wu hanrong on behalf of YBJ-ASg collaboration 2008.09.24 TeVPA-IV@IHEP
Gamma-ray flux from WIMP annihilation: Indirect Dark Matter search Astrophysics : Dark matter halo Particle Physics From Observation
Target of indirect search • Galactic Halo • external galaxies • galaxy clusters • substructures • Galactic Center(GC) • Local Group galaxies • Mini-spikes around IMBH
Indirect DM search—ground based observatory IACT arrays Advantage: Good angular resolution; gamma/hadron discrimination Disadvantage: limited FOV and duty cycle Advantage: large FOV, 90% duty cycle Disadvantage: no good gamma/hadron identifintification EAS arrays
Tibet AS Observatory • a.s.l. 4300 m (YBJ , Tibet) • 606g/cm2 • Large field of view • Duty cycle (>90%) • Mode Energy: ASγ(~3TeV) ARGO ASγ
Schematic map of the array and data using in analysis Tibet-II Tibet-IIIB4 Statistic (after selection): ~1.86*10^10
Equal 迭代 • analysis method
1.M31(10.7,41.3) Non: 2876965 Noff: 2875325.3 Nexc: 1639.7 Significance: 0.97 M31 全天图以及M31显著性 2. No high siginificant point (>5sigma) except known source crab and Mrk421 is detected
-------substructure (>5 ) 2. 90%C.L. limit— substructure Significance for BKG Significance for BKG+DM signal
2. 90%C.L. limit— substructure preliminary
Conclusions • Detect no any substructure in the field of YBJ ASgamma observatory • Detect no DM from M31 • 90% C.L. upper limit on “thermally averaged annihilation cross section” between 10^-19cm^3s^-1 and 10^-22cm^3s^-1 is given • Future search, ARGO-YBJ(~300GeV)
1. 90%C.L. Flux limit— M31 90%C.L. flux limit: DM spectrum From Observation Monte Carlo
2. 90%C.L. Flux limit— substructure -----Number of substructure for 800 toy MC trials BKG BKG+DM signal