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Observation of Cosmic-Ray Anisotropy in the Southern Hemisphere with 12 yr of Data Collected by the IceCube Neutrino Observatory
Journal article   Open access   Peer reviewed

Observation of Cosmic-Ray Anisotropy in the Southern Hemisphere with 12 yr of Data Collected by the IceCube Neutrino Observatory

Ice Cube Collaboration, R Abbasi, M Ackermann, J Adams, S K Agarwalla, T Aguado, J. A. Aguilar, M Ahlers, J M Alameddine and M. Hostert
Astrophysical Journal, Vol.981(2), 182
03/10/2025
DOI: 10.3847/1538-4357/adb1de
url
https://doi.org/10.3847/1538-4357/adb1deView
Published (Version of record) Open Access

Abstract

We analyzed the 7.92 × 1011 cosmic-ray-induced muon events collected by the IceCube Neutrino Observatory from 2011 May 13, when the fully constructed experiment started to take data, to 2023 May 12. This data set provides an up-to-date cosmic-ray arrival direction distribution in the Southern Hemisphere with unprecedented statistical accuracy covering more than a full period length of a solar cycle. Improvements in Monte Carlo event simulation and better handling of year-to-year differences in data processing significantly reduce systematic uncertainties below the level of statistical fluctuations compared to the previously published results. We confirm the observation of a change in the angular structure of the cosmic-ray anisotropy between 10 TeV and 1 PeV, more specifically in the 100–300 TeV energy range. For the first time, we analyzed the angular power spectrum at different energies. The observed variations of the power spectra with energy suggest relatively reduced large-scale features at high energy compared to those of medium and small scales. The large volume of data enhances the statistical significance at higher energies, up to the PeV scale, and smaller angular scales, down to approximately 6° compared to previous findings.
Physical Sciences 0201 Astronomical and Space Sciences 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics 0306 Physical Chemistry (incl. Structural) 5101 Astronomical sciences 5107 Particle and high energy physics 5109 Space sciences ARRIVAL DIRECTIONS Astronomy & Astrophysics ICETOP INTENSITY Science & Technology SEARCH SMALL-SCALE ANISOTROPIES SPECTRUM TEV TRACK RECONSTRUCTION

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