Full-Sky Analysis of Cosmic-Ray Anisotropy with IceCube and HAWC

TL;DR

This paper presents a joint analysis of cosmic-ray anisotropy across the entire sky by combining data from IceCube and HAWC, aiming to improve understanding of small anisotropies in cosmic-ray arrival directions.

Contribution

It introduces a novel combined analysis method for all-sky cosmic-ray anisotropy using data from IceCube and HAWC, addressing previous sky coverage limitations.

Findings

Preliminary results of combined anisotropy analysis

Methodology for merging data from different detectors

Insights into the anisotropy's energy dependence

Abstract

During the past two decades, experiments in both the Northern and Southern hemispheres have observed a small but measurable energy-dependent sidereal anisotropy in the arrival direction distribution of galactic cosmic rays. The relative amplitude of the anisotropy is $10^{-4} - 10^{-3}$. However, each of these individual measurements is restricted by limited sky coverage, and so the pseudo-power spectrum of the anisotropy obtained from any one measurement displays a systematic correlation between different multipole modes $C_\ell$. To address this issue, we present the preliminary status of a joint analysis of the anisotropy on all angular scales using cosmic-ray data from the IceCube Neutrino Observatory located at the South Pole ($90^\circ$ S) and the High-Altitude Water Cherenkov (HAWC) Observatory located at Sierra Negra, Mexico ($19^\circ$ N). We describe the methods used to combine the IceCube and HAWC data, address the individual detector systematics and study the region of overlapping field of view between the two observatories.