E. Kido

Comparison of CORSIKA and COSMOS simulations

Ultra‐high‐energy cosmic rays (UHECRs) refer to cosmic rays with energy above 1018 eV. UHECR experiments utilize simulations of extensive air shower to estimate the properties of UHECRs. The Telescope Array (TA) experiment employs the Monte Carlo codes of CORSIKA and COSMOS to obtain EAS simulations. In this paper, we compare the results of the simulations obtained from CORSIKA and COSMOS and report differences between them in terms of the longitudinal distribution, Xmax‐value, calorimetric energy, and energy spectrum at ground.

Search for small clusters by auto‐correlation analysis from Telescope Array

The Telescope Array (TA) experiment detects air showers induced by extremely high energy cosmic rays in the middle west of Utah, USA. The TA experiment consists of two different types of detector such as atmospheric fluorescence detectors (FDs) and surface array particle detectors (SDs). The SD observation started in March 2008. This paper describes the search for the small scale clusters from 850‐days TA SD data by auto‐correlation method for several energy thresholds. As a result, there is no indication of small scale clusters by TA SD.

Anisotropy and point sources searches in the Telescope Array data

The first two years of the Telescope Array surface detector data are analysed for anisotropy. First, we calculate the angular correlation function of the cosmic ray events at energies larger 10 and 40 EeV and show that there is no significant clustering either at small or large angular scales. We then test previously existing claims for correlation with putative classes of point sources of UHECR.