Anisotropy Results of the Telescope Array Experiment
ORAL
Abstract
We report the results of ultra-high energy cosmic ray anisotropy in the Northern hemisphere obtained using data of the Telescope Array (TA) experiment. TA is located in the desert near Delta, UT, and it consists of a surface detector array of 507 plastic scintillation counters, effectively covering a \textasciitilde 700 km$^{\mathrm{2}}$ area on the ground, which is overlooked by 3 fluorescence detector stations. This work consists of two parts. First, we present the result of the search for EeV protons of Galactic origin in the TA data in 10$^{\mathrm{18.0}}$ to 10$^{\mathrm{18.5\thinspace }}$eV range and place an upper limit on the fraction of the Galactic protons in the TA spectrum. Then we report anisotropies above 10 EeV that are seen in the TA spectrum and in the TA event arrival directions on the sky. Discussion of the TA spectrum anisotropy and a local excess of events above 57 EeV near the direction of Ursa Major, called the ``TA Hot Spot'', will be given. We also compare the TA spectrum with the spectrum measured by the Pierre Auger Observatory in a declination band that is commonly seen by both experiments.
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Authors
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Dmitri Ivanov
Univ of Utah