Results from the Telescope Array Experiment
04 Jul 2011
1Institute for Cosmic Ray Research, University of Tokyo, Kashiwanoha 5-1-5, Kashiwa, Chiba 277-8582, Japan
Abstract. The Telescope Array experiment is the largest hybrid detector to observe ultra-high energy cosmic rays in the northern hemisphere. The observation started in November 2007 for Fluorescence Detector (FD) and in March 2008 for Surface Detectors (SD). Here we present the preliminary results of energy spectra measured by three different methods, mass composition, photon search and AGN correlation search from the Telescope Array. The energy spectra measured by the Middle-Drum FD station, which is the refurbished detector of the High Resolution Fly's Eye (HiRes) experiment, and hybrid technique with two new FDs and SD were consistent with the result of HiRes. The systematic error of the energies in hybrid measurement is 19%. The SD spectrum showed the suppression above 1019.75 eV with 3.5σ away from the continuous spectrum. The measured mass composition with stereo technique of new FDs was consistent with pure proton model between 1018.6 eV to 1019.3 eV. Photon search resulted in an improved flux limit above 1019 eV. The result of AGN correlation from TA was consistent with background.