GZK Horizons and the Anisotropy of Highest-energy Cosmic Ray Sources

TL;DR

This paper investigates how the distribution of ultrahigh energy cosmic ray sources, especially local over-densities, influences GZK horizons and anisotropy, informed by Pierre Auger data and testable in future observations.

Contribution

It introduces models of UHECR source distributions with local over-densities and analyzes their impact on GZK horizons and anisotropy, incorporating energy calibration effects.

Findings

Local over-density models can significantly affect GZK horizon estimates.

Energy calibration influences the interpretation of UHECR data.

Proposes testable scenarios for future cosmic ray astronomy.

Abstract

Motivated by recent Pierre Auger result on the correlation of the highest-energy cosmic rays with the nearby active galactic nuclei, we explore possible ultrahigh energy cosmic ray (UHECR) source distributions and their effects on GZK horizons. Effects on GZK horizons by local over-density of UHECR sources are examined carefully with constraints on the degree of local over-density inferred from the measured UHECR spectrum. We include the energy calibration effect on the Pierre Auger data in our studies. We propose possible local over-densities of UHECR sources which are testable in the future cosmic ray astronomy.