Upper limit on the fraction of the cosmic ray flux from a separable source in the energy interval (1017 -1019 eV), estimated using data from the Yakutsk array

Abstract

Arrival directions of ultra-high energy cosmic rays (UHECRs) in the equatorial system, detected with the Yakutsk array in the energy range (1017 -10 19 eV), are re-analyzed using a new approximation for the zenith angle distribution of the event rate of extensive air showers (EAS). While the null hypothesis cannot be rejected based on the data used here, an upper limit on the fraction of cosmic rays from a separable source in the uniform background is derived as a function of declination and energy.