Kolmogorov-Smirnov test as a tool to study the distribution of ultra-high energy cosmic ray sources

TL;DR

This paper evaluates the two-dimensional Kolmogorov-Smirnov test for analyzing the spatial distribution of ultra-high energy cosmic ray sources, assessing its ability to distinguish between different astrophysical models.

Contribution

It demonstrates how the 2D Kolmogorov-Smirnov test can differentiate source models of cosmic rays and extend previous analyses beyond simple isotropy testing.

Findings

The test can reject isotropic source distributions.

It supports distinguishing between AGN and galaxy-based models.

The method extends previous statistical approaches.

Abstract

We analyze in detail the two-dimensional Kolmogorov-Smirnov test as a tool to learn about the distribution of the sources of the ultra-high energy cosmic rays. We confront in particular models based on AGN observed in X rays, on galaxies observed in HI and isotropic distributions, discussing how this method can be used not only to reject isotropy but also to support or reject specific source models, extending results obtained recently in the literature.