A Study on Anisotropy in the Arrival Directions of Ultra-High-Energy Cosmic Rays Observed by Pierre Auger Observatory

TL;DR

This paper investigates the anisotropy in ultra-high-energy cosmic rays observed by the Pierre Auger Observatory, identifying a prominent excess near Centaurus A and a void region, providing insights into cosmic ray origins.

Contribution

It introduces a point source correlational angular distance method to analyze anisotropy in UHECRs, highlighting specific regions associated with potential sources.

Findings

Anisotropy characterized by one excess and one void region.

Excess region near Centaurus A supports it as a UHECR source.

Void region near south pole constrains isotropic background.

Abstract

We study the anisotropy in the arrival directions of PAO UHECRs, using the point source correlational angular distance distribution. The result shows that the anisotropy is characterized by one prominent excess region and one void region. The excess region is located near the Centaurus A direction, supporting that the Centaurus A is a promising UHECR source. The void region near the south pole direction may be used to limit the diffuse isotropic background contribution.