Search for point sources of ultra-high-energy cosmic rays above 10 19eV using a maximum likelihood ratio test

Abstract

We present the results of a search for cosmic ray point sources at energies above 1.0 × 1019eV in the HiRes stereo data set. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. The search is extended to the combined data set of HiRes data above 1.0 × 1019eV and AGASA data above 4.0 × 10 19eV. In both cases, no statistically significant clustering of events consistent with a point source is found.