Observation of Cosmic-Ray Anisotropy in the Southern Hemisphere with 12 yr of Data Collected by the IceCube Neutrino Observatory
Abstract We analyzed the 7.92 × 10 11 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.
Authors
- Y. Ashida
- Timothy Aguado
- J. V. Mead (ORCID: https://orcid.org/0000-0003-0875-2533)
- Sanjib Kumar Agarwalla (ORCID: https://orcid.org/0000-0002-9714-8866)
- C. Argüelles (ORCID: https://orcid.org/0000-0003-4186-4182)
- A. Sicilia‐Aguilar (ORCID: https://orcid.org/0000-0002-8421-0851)
- R. Babu
- M. Ackermann (ORCID: https://orcid.org/0000-0001-8952-588X)
- K. Andeen (ORCID: https://orcid.org/0000-0001-9394-0007)
- N. M. Amin
- Jean-Marco Alameddine (ORCID: https://orcid.org/0000-0002-9534-9189)
- Rasha Abbasi (ORCID: https://orcid.org/0000-0001-6141-4205)
- M. Ahlers (ORCID: https://orcid.org/0000-0003-0709-5631)
- D. J. Koskinen (ORCID: https://orcid.org/0000-0002-0514-5917)
- S. Athanasiadou
- A. Søgaard (ORCID: https://orcid.org/0000-0002-0823-056X)
- J. Adams
Institutions
- Institute of Particle Physics (CA)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-03-07
- DOI
- https://doi.org/10.3847/1538-4357/adb1de
- Citations
- 8
- Primary Topic
- Astrophysics and Cosmic Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 14.96
Funders
- National Science Foundation
- U.S. Department of Energy
- University of Wisconsin-Madison
- Loyola University Chicago
- Michigan State University
- Marquette University
- Deutsche Forschungsgemeinschaft
- Bundesministerium für Bildung und Forschung
- Fonds De La Recherche Scientifique - FNRS
- Belgian Federal Science Policy Office
- Fonds Wetenschappelijk Onderzoek
- Helmholtz Alliance for Astroparticle Physics
- College of Engineering, Michigan State University
- Deutsches Elektronen-Synchrotron
- Office of Polar Programs
- Office of Advanced Cyberinfrastructure
- Office of Experimental Program to Stimulate Competitive Research