Anisotropy search above 1 EeV using the Telescope Array surface detector data
Presented by Dmitri IVANOV
In 1999, the Akeno Giant Air Shower Array (AGASA) reported a 4 sigma excess in the 1 - 2 EeV cosmic ray intensity near the Galactic Center (G.C.) and a 4 sigma deficit near the Galactic Anti-Center (G.A.C.) . In 2007, a similar 3.5 sigma deficit near the G.A.C. was seen by the High Resolution Fly's Eye (HiRes) experiment, while a search near the G.C. was inconclusive. We have performed an independent test of HiRes and AGASA results using 3 years of the Telescope Array (TA) surface detector (SD) data, collected in the period May, 2008 – May, 2011. We describe our methods of calculating the exposure on the sky by a detailed Monte-Carlo simulation and its application for determining the statistical significance of the results and testing the anisotropy search methods. We present a significance map of cosmic ray arrival directions as seen by the TA SD, a full-sky harmonic analysis in right ascension, and compare these results with HiRes and AGASA.