1. TeV Cosmic-ray Anisotropy & Tibet Yangbajing Observatory Qu Xiaobo Institute of High Energy Physics

2. ARGO Hall Tibet AS  array Yangbajing Observatory

3. The Tibet Air shower Array –Located at an elevation of 4300 m (Yangbajing, China) –Atmospheric depth 606g/cm 2 –Wide field of view (Dec. -15º,75º ) –High duty cycle (>90%) –Angular resolution (~0.9 0 ) Advantage----measurement of Cosmic ray Large scale anisotropy

4. OUTLINE Large scale anisotropy in sidereal time Energy dependence Time evolution Models Compton-Getting effect Solar time anisotropy Periodicity Summary

5. Energy dependence Sidereal time anisotropy Amenomori, APJ, 2005 Harmonic analysis “ East-west”(E-W) subtraction method increase independent decrease

6. A. D. Erlykin, A. W. Wolfendale, Astropart. Phys. 25, 183(2006) Anisotropy expected by CR production and propagation (R – rigidity) (δ ~ 0.3-0.6 ) Important probe, discover CR origin, study CR propagation. Diffusion model: The amplitude of anisotropy increase with the energy! 1.Random character of SN explosions; 2.Mixed primary mass composition; 3.Possible e ff ect of the single source; 4. The Galactic Halo;

7. Sidereal time anisotropy Tail-In max. shifts earlier in the south Tail-In Loss-Cone Tail-In Loss-Cone Hall et al. (JGR, 104, 1999) Hall et al. (JGR, 103, 1998) Structure analysis NFJ model Tail-in Loss-cone Gaussian analysis

8. Zenith On-source Off-source ——Global fitting method Equal Two dimension analysis method Zenith belt

9. The CR anisotropy is fairly stable in two samples. Three Componets ： I--------Tail-in; II-------Loss-cone III------Cygnus region ； Tibet measurement in two dimensions > M. Amenomori et al., Science, 314 429 (2006)

10. Large scale anisotropy in two dimension Milagro Super-Kamiokande-I Also by ARGO, Icecube

11. 4 TeV 6.2 TeV 12 TeV 50 TeV 300 TeV Celestial Cosmic Ray intensity map in five energy range <12TeV Energy independent >12TeV Fade away “ Tail-in” effect exists in 50TeV, rule out the solar causation. Energy dependence

12. Sidereal time anisotropy by ARGO 1.5TeV 0.7TeV 3.9TeV Median energy > ICRC0814,2009 Energy dependence Consistent with the 1D observations, finer structure in 2D

13. Sidereal time anisotropy in 9 Phases (1999-2008) >, M. Amenomori et al., ApJ 711, 119 (2010) Temporal Variations Stable Insensitive to solar activities Improved analysis method, more statistic.

14. Temporal Variations Time Evolution of the Sidereal Anisotropy The fundamental harmonic increase in amplitude with time. Milagro observation No steady increase Matsushiro Observation Tibet Observation 1999-2008 2000-2007

15. Sidereal time anisotropy in two hemisphere Tibet III Icecube

16. Sidereal time anisotropy in Galactic coordinate Tibet III Icecube Cosmic ray flows in three directions Inward flows Outward flows Electrically neutral state Excess X.B.Qu et al., arXiv:1101.5273

17. Magnetic field induced by Cosmic ray flows Extend the anisotropy image observed in the solar vicinity to the whole Galaxy. Biot-Savart Law A0 dynamo modelJ.L. Han,1997 1.Magnetic Field Structure, Consistent 2.The extension of the local anisotropy to the whole Galaxy is reasonable. X.B.Qu et al., arXiv:1101.5273

18. Alternative Model of the Sidereal time anisotropy Amenomori, M., et al. 2010, Astrophys. Space Sci. Trans., 6, 49 Global +Midscale Anisotropy Two intensity enhancements along a Hydrogen Deflection Plane uni-directional flow +bi-directional flow Local interstellar magnetic field Residual anisotropy after subtracting I n,m I n,m I n,m (GA) I n,m (MA) Residual anisotropy after subtracting I n,m (GA)

19. LIMC (Local Interstellar Magnetic Cloud) model Local Interstellar Cloud, egg-shaped cloud, 93 pc 3. Cosmic ray density (n) lower inside LIC than outside, adiabatic expansion ⊥ Perpendicular ∥ Parallel uni-directional flow (UDF) ⊥ bi-directional flow (BDF) ∥ LISMF Alternative Model of the Sidereal time anisotropy

20. Known origin of large scale anisotropy —— Compton-Getting Effect Δ I = (  + 2 ) v c cos  A.H. Compton and I.A. Getting, Phys. Rev. 47, 817(1935) Due to the solar motion around galactic center jE-E- 8 V=220km/s,  Expected dipole effect We could observe

21. Expected Amp= 0. 16% The statistic error 0. 026% ， ~5σ rule out the Compton- Getting effect. Celestial Cosmic Ray intensity map for 300 TeV These results have an implication that cosmic rays in this energy range is still strongly deflected and randomized by the Galactic magnetic field in the local environment.

22. Δ I = (  + 2 ) v c cos  Due to terrestrial orbital motion around the Sun j 8 E-E- V=30km/s,  D.J. Cutler, D.E. Groom, Nature 322, L434 (1986) Known origin of large scale anisotropy —— Compton-Getting effect Differential E spectrum : The amplitude is ~0.04%

23. ——Compton-Getting effect （ 12TeV ） The solar time anisotropy is stable in two intervals with different solar activity The 1D modulation (solid line) is consistent with the expected one (dash line) 。 Tibet measurement in solar time I

24. With the compton-getting effect subtracted. The amplitude ～ 0.04%. ——Additional effect (4TeV) Tibet measurement in solar time II Preliminary

25. Periodicity search in 3 energy ranges Solar diurnal. Compton- Getting effect Sidereal-diurnal Sidereal semi-diurnal >, A.-F. Li Nuclear Physics B,, 529, 2008.

26. Summary Yangbajing Observatory successfully observed the Cosmic ray anisotropy.(0.7TeV-300TeV) Energy dependence, time evolution, Periodicity analysis of the anisotropy In the sidereal time frame, revealing finer details of the anisotropies components “tail-in” and “loss-cone” and “Cygnus” region direction. Models given. origin??? In the solar time frame, Compton-Getting effect is observed in 12TeV, An additional modulation appears to exist in case of low energy.

27. 中意 ARGO 实验大厅 中日 AS  探测阵列

28. Anisotropy Observations in other periods Anti sidereal time Ext-sidereal time No signal is expected, the amplitude observed is within statistic error.

29. 银河系磁场强度为 3uG 时 带电粒子在传播过程中受磁场影响而偏离其原本方向．星际磁 场就像一个搅拌机，将宇宙线粒子搅拌得各向同性 ． 银河宇宙线在磁场中传播 Cygnus 方向 回旋半径 3TeV 对应 0.001pc (200AU)

32. ——NFJ model Sidereal time anisotropy components

33. Nagashima, Fujimoto, Jacklyn (JGR, 103, 1998) Hall et al. (JGR, 103, 1998) Tail-In Loss-Cone Tail-In max. shifts earlier in the south

34. One-dimensional observation Sidereal time anisotropy

35.  太阳时各向异性 低能处比较明显，随刚度幂律分布 存在截止刚度 ，经测量 随太阳活动有 11 年的周期变化，活动极小时，低至几 GV ，极大时，可达 200GV 最近观测发现， 600GV 宇宙线太阳时各向异性仍受到太阳活 动的调制； Tibet ASγ 在 4TeV 处观测到超出 CG 效应的太阳 时各向异性，高能处与预期 CG 效应一致 宇宙线及大尺度各向异性

36. Medium scale anisotropy Milagro ARGO Tibet-III

37. Large scale anisotropy Milagro Tibet-III