학술논문
Study of the Shadows of the Moon and the Sun with VHE Cosmic Rays
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article
Author
Atkins, R; Benbow, W; Berley, D; Chen, M-L; Coyne, DG; Delay, RS; Dingus, BL; Dorfan, DE; Ellsworth, RW; Evans, D; Falcone, A; Fleysher, L; Fleysher, R; Gisler, G; Goodman, JA; Haines, TJ; Hoffman, CM; Hugenberger, S; Kelley, LA; Leonor, I; Macri, J; McConnell, M; McCullough, JF; McEnery, JE; Miller, RS; Mincer, AI; Morales, MF; Nemethy, P; Ryan, JM; Schneider, M; Shen, B; Shoup, A; Sinnis, G; Smith, AJ; Sullivan, GW; Thompson, TN; Tumer, OT; Wang, K; Wascko, MO; Westerhoff, S; Williams, DA; Yang, T; Yodh, GB
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Abstract
Milagrito, a prototype for the Milagro detector, operated for 15 months in1997-8 and collected 8.9 billion events. It was the first extensive air shower(EAS) array sensitive to showers intiated by primaries with energy below 1 TeV.The shadows of the sun and moon observed with cosmic rays can be used to studysystematic pointing shifts and measure the angular resolution of EAS arrays.Below a few TeV, the paths of cosmic rays coming toward the earth are bent bythe helio- and geo-magnetic fields. This is expected to distort and displacethe shadows of the sun and the moon. The moon shadow, offset from the nominal(undeflected) position, has been observed with high statistical significance inMilagrito. This can be used to establish energy calibrations, as well as tosearch for the anti-matter content of the VHE cosmic ray flux. The shadow ofthe sun has also been observed with high significance.