Search for Correlations between HiRes Stereo Events and Active Galactic Nuclei

TL;DR

This study searched for correlations between ultrahigh energy cosmic rays and active galactic nuclei but found no significant associations in the northern hemisphere data, contrasting with positive results reported by the Pierre Auger collaboration in the south.

Contribution

It provides a systematic analysis of cosmic ray-AGN correlations using established search parameters and compares different statistical methods for chance probability estimation.

Findings

No significant correlations in northern hemisphere data.

Most significant correlation had a 24% chance probability.

Results contrast with southern hemisphere findings by the Pierre Auger collaboration.

Abstract

We have searched for correlations between the pointing directions of ultrahigh energy cosmic rays observed by the High Resolution Fly's Eye experiment and Active Galactic Nuclei (AGN) visible from its northern hemisphere location. No correlations, other than random correlations, have been found. We report our results using search parameters prescribed by the Pierre Auger collaboration. Using these parameters, the Auger collaboration concludes that a positive correlation exists for sources visible to their southern hemisphere location. We also describe results using two methods for determining the chance probability of correlations: one in which a hypothesis is formed from scanning one half of the data and tested on the second half, and another which involves a scan over the entire data set. The most significant correlation found occurred with a chance probability of 24%.