Extensive air showers' arrival direction distribution by the TSU array under GELATICA experiment
The distribution of the arrival zenith angle of the Extensive Air Showers (EAS) with a wide range of a total number of charged particles is studied using the experimental data obtained using the EAS 4-detector array 'TSU' in Tbilisi. The station is a part of the GELATICA net in Georgia (GEorgian Large-area Angle and TIme Coincidence Array), which is devoted to the study of possible correlations in the arrival times and directions of separate EAS events over large distances. It is shown that the distribution function with the conventional exponential dependence of showers' flux on absorbing air thickness provides a good approximation for the arrival direction distribution. The dependence of the EAS absorption path estimation on the angular trimming boundary of data set is studied; the necessity of strict verification of the used value of data trimming boundary is stated.