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Hongbo Hu ( huhb@ihep.ac) For Tibet AS  collaboration

A Northern Sky Survey for Both TeV CR anisotropy and -ray Sources with Tibet Air Shower Array. Hongbo Hu ( huhb@ihep.ac.cn) For Tibet AS  collaboration. The Tibet AS-gamma Experiment ; Two Analyses Methods; Preliminary Results; Discussion and Conclusions.

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Hongbo Hu ( huhb@ihep.ac) For Tibet AS  collaboration

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  1. A Northern Sky Survey forBoth TeV CR anisotropy and -ray Sources with Tibet Air Shower Array Hongbo Hu (huhb@ihep.ac.cn) For Tibet AS collaboration • The Tibet AS-gamma Experiment ; • Two Analyses Methods; • Preliminary Results; • Discussion and Conclusions. 2004.8 Institute of High Energy Physics

  2. YangBaJing Observatory and its Experiments • Located at an elevation of 4300 m (Yangbajing , China) • Atmospheric depth 606g/cm2 • Wide field of view • High duty cycle (>90%) ASγ air shower array ARGO Experimental Hall

  3. Tibet Air Shower Array Tibet-HD Tibet-III Tibet-HD Tibet array: ~250 x 250 m2 HD: 60 x 60m2 Tibet-III: ~150x150 m2 3,600m2 (in area)

  4. Zenith North Pole MethodI-----Equal-zenith method 6.8°<zenith<40.0° • Making use of the fact that events are uniformly distributed within equal-zenith belt; • 10 off-source windows (side band) are chosen to estimate BKG. On-source Off-source

  5. Equal ! Method II----Global CR. Intensity fitting method Zenith Equal ? All sky survey based on an anisotropy correction of relative CR intensity, which is obtained by LSQ fitting for the data in each of equal zenith ring

  6. Large scale anisotropy (by method II) DEC I - 1 ～±0.1% Duldig, PASA,Vol18,No.1 RA.

  7. Anisotropy measurements agree with each other from using HD detector or TibetIII detector, means small systematic effects. Large scale anisotropy of diff. Data sample

  8. Large scale anisotropy correction σ=1.258 σ=1.018 After subtraction Before subtraction

  9. Crab • Sky Map List of sky cells with clustered directions (24)having statistic significance larger than 4.0σ. Mrk421 (88.8,30.2)

  10. Discussion Hot point I ---evt. No.9 (88.8°, 30.2 °) b=+5˚ b=+5˚ 4.5 σ 3.7σ b=0˚ b=0˚ b=-5˚ b=-5˚ • SNR counterpart G179.0+2.6, RA : 88.42 DEC :31.08 Size (/arc min): 70 Type: Shell b=+5˚ b=0˚ 5.6 σ b=-5˚

  11. b=+5˚ b=+5˚ b=+5˚ b=0˚ b=0˚ b=0˚ b=-5˚ b=-5˚ b=-5˚ Hot Point II -- No.18(304.3 °, 36.7 °), No19(309.9 °, 39.6 °) • Amenomori,in Proc.27th ICRC,2315.Observed4.15 σ; • S.W. Cui and C.T. Yan, in Proc. 28th ICRC, 2315. Observed 4 σ; • EGRET counterpart 3EG J2016+3657 RA :304.008 DEC : 37.2 • Milagro (306.6,38.9) 4.2 σ (Atkins,R., et al 2004, ApJ, 608,680) ~0 σ 2.9 σ 4.5 σ 3.9 σ 4.2 σ 4.4 σ

  12. Up flux limit (by method I) (30 degree of declination related to YBJ zenith direction)

  13. Conclusions • Large scale anisotropy of CR. intensity with a magnitude about 0.1% are observed in two dimensions in TeV energy range. • Crab and Mrk421 are detected with 5 σ level. • No other significant point source is found, and an upper-flux limit curve is given

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