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85 people from 25 institutes in Japan and China

6 th IGPP meeting in Hawaii: March 21, 2007. Implication of the sidereal anisotropy of ~10 TeV (10 13 eV) cosmic ray intensity observed with the Tibet III air shower array.

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85 people from 25 institutes in Japan and China

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  1. 6th IGPP meeting in Hawaii: March 21, 2007 Implication of the sidereal anisotropy of~10 TeV (1013 eV) cosmic ray intensity observed with the Tibet III air shower array M. Amenomori, S. Ayabe, X. J. Bi, D. Chen, S. W. Cui, Danzengluobu, L. K. Ding, X. H. Ding, C. F. Feng, Zhaoyang Feng, Z. Y. Feng, X. Y. Gao, Q. X. Geng, H. W. Guo, H. H. He, M. He, K. Hibino, N. Hotta, Haibing Hu, H. B. Hu, J. Huang, Q. Huang, H. Y. Jia, F. Kajino, K. Kasahara, Y. Katayose, C. Kato, K. Kawata, Labaciren, G. M. Le, A. F. Li, J. Y. Li, Y.-Q. Lou, H. Lu, S. L. Lu, X. R. Meng, K. Mizutani, J. Mu, K. Munakata, A. Nagai, H. Nanjo, M. Nishizawa, M. Ohnishi, I. Ohta, H. Onuma, T. Ouchi, S. Ozawa, J. R. Ren, T. Saito, T. Y. Saito, M. Sakata, T. K. Sako, T. Sasaki, M. Shibata, A. Shiomi, T. Shirai, H. Sugimoto, M. Takita, Y. H. Tan, N. Tateyama, S. Torii, H. Tsuchiya, S. Udo, B. Wang, H. Wang, X. Wang, Y. G. Wang, H. R. Wu, L. Xue, Y. Yamamoto, C. T. Yan, X. C. Yang, S. Yasue, Z. H. Ye, G. C. Yu, A. F. Yuan, T. Yuda, H. M. Zhang, J. L. Zhang, N. J. Zhang, X. Y. Zhang, Y. Zhang, Yi Zhang, Zhaxisangzhu and X. X. Zhou (Tibet AS collaboration) 85 people from 25 institutes in Japan and China

  2. Cosmic ray observation with AS array 1ry g Air shower array Muon detector Neutron monitor • Ground-based detectors measure byproducts of the interaction of primary cosmic rays (mostly protons) with Earth’s atmosphere. • AS array measures electromagnetic component in the cascade shower. • AS array also responds to 1ry g-rays,while the muon detector respond only to 1ry protons.

  3. Yangbajing ~300 km Lasa Yangbajing 90゜53E, 30゜11N 4,300 m a.s.l. Tibet ASγ experiment Tibet@China

  4. 533 counters of 0.5 m2 each placed on a 7.5mx7.5m square grid • 22,050 m2 detection area Achieved… Highest statistics & Best angular resolution in multi-TeV region • trigger rate ~ 680 Hz • angular res. ~ 1 Resolving the incident direction

  5. d=90o d=30.1o d=30.1o AS flux varies for more than an order of magnitude with the zenith angle due to the different atmospheric depth. ● Sidereal anisotropy on the spinning Earth The zenith direction at Yanbajing is d=30.1o. ● With the spin of Earth, the zenith direction travels along d=30.1o . ● Fixed direction in the horizontal coordinate travels along d=const. for 360o of right ascension once every one sidereal day. ● The average flux in each d-band is subtracted.

  6. 2D sky map of CR intensity by Tibet AS “Normalized” intensity map (5°x5° pixels) declination (º) Galactic plane Geographical equator Nose direction 90° < 120° < 180° Bi-directional + Uni-directional right ascension (º) ~120° (Amenomori et al., Science, 314, 2006) Significance map

  7. LIC (Local Interstellar Cloud) • RL~ 0.01pc (for 10TeV p in 1mG) • Dist. to LIC boundary ~26km/s3000y =0.08pc • Probably within 1 m.f.p. in the weak • scattering regime T~7000K, nH~0.1/cc Ionization rate~0.52 H Redfield & Linsky, ApJ, 535, 2000 2 pc l=90 He Lallement’s Interstellar B plane (Lallement et al., Science, 307, 2005) l=180 GC lB= 205~240 bB= -38~-60 (or the opposite direction) l=270

  8. LIMC (Local Interstellar Magnetic Cloud) model If cosmic ray density (n) is lower inside LIC than outside…. LIC n High Uni-directional flow (Bxn) n Low G cloud n 26 km/s Bi-directional flow Interstellar B 29 km/s

  9. Best-fitting (preliminary) : Bi-directional (DI/I)cal = a1cos1(a1,d1) : Uni-directional + a2+cos2 2(a2,d2) for 0 2/2 + a2-cos2 2(a2, d2) for /2 2  1, 2 : angles from reference axes First choose orientations of reference axes… a1,a2&d2 (or d1): (a2, d2)  (a1, d1) then a1, a2+&a2-are given by linear LSM. d.o.f. with 6 free parameters is large as… 90x360/(5x5)-6=1,290 Result: Uni-directional Bi-directional a1=0.0016, a2+=0.0018, a2-=0.0010 a1=27.5,d1=47.5, a2=97.4,d2=-17.5

  10. Best-fit intensity distribution “Normalized” intensity (average over dec.-band is subtracted) Original intensity Uni-direct. + Bi-direct. = Sum

  11. Best-fit performance Cygnus region Crab Mrk421 observation model residual (obs.-model)/error • Large-scale feature is well reproduced.2/d.o.f. = 2.493 • (“Trough”, “Peak” and broad enhancement aroundCygnus region) • “Skewed” profile of “Peak” needs to be modeled further.

  12. Comparison with UG-m in two-hemispheres UG-m in Japan V (35°N) : LIMC model (Tibet AS) Tibet AS : Lallement’s B UG-m in Tasmania N (4°N) Tibet AS UG-m in Tasmania V (36°S) Best-fit B direction may be different when unbiased, by properly taking account of the data in southern hemisphere. Tibet AS experiment cannot observe southern hemisphere. UG-m @0.5 TeV Hall et al., JGR, 103, 1998 &104, 1999)

  13. Summary : Lallement’s B + + : B in this model (bi-directional) -0.0016 +0.0010 - : heliotail (He) b (°) +0.0016 + + +0.0018 l (°) • Large-scale feature of 2D-sky map is well reproduced by the model. • (“Trough”, “Peak” and broad enhancement around Cygnus region) • “Skewed” profile of the observed “Peak” needs to be modeled further. • The model may be biased by the lack of southern hemisphere data. • Best-fit B-orientation is in a reasonable agreement with Lallement et al. (2005). Original intensity map (in galactic coordinate) White lines show contour map of the distance to LIC boundary by Redfield & Linsky (2000).

  14. Comparison with UG- observations Two-hemisphere UG- observations @~0.5 TeV (5°x5° pixels) (Hall et al., JGR, 103, 1998 &104, 1999) (15°x15° pixels) Large-scale distribution of proton intensity (not -ray) Deep UG- observations by Super Kamiokande @~10 TeV Guillian et al., PRD, in press (2007)

  15. Energy dependence “Normalized” intensity Significance 4 TeV 6 No significant E-dependence up to ~100 TeV 12 50 100

  16. d=90o d=90o d=30.1o d=30.1o • 長期安定稼動 • 大気効果の補正 • （等天頂角法、E-W法） 恒星時日周変動 系統誤差  0.01%を実現 0 6 12 18 24 Local sidereal time (hour) 銀河異方性と恒星時日周変動 赤緯依存性を観測できない。 （自転軸に平行な流れは検出不可）

  17. Energy responses to 1-ry CRs μ-on AS（Tibet III）

  18. Nagashima, Fuｊimoto & Jacklyn (1998) Loss-cone Loss-cone Tail-In Tail-In E-spectra of SDV amplitude （Before Tibet III） • Both TI & LC @~300GeV • No significant TI @10TeV • TI has a soft E-spectrum • J/J~γE/E with const. E • ⇒ accl. in heliotail?

  19. Tibet III results (AS@10TeV) Amenomori et al. (ApJL, 626, 2005) • Tibet III all-dec. is consistent with Nor. • TI seen in the south • TI phase shifts earlier in south (amp. larger)

  20. 27° 28±15° Lallement et al. (2004) Tibet AS Gurnett et al. (2006)

  21. gal. East gal. North gal. center gal. East

  22. Positive (qA>0) Negative (qA<0) (meridian) (equatorial) (meridian) (equatorial) 0.5 TV 1 TV 10 TV

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