OBSERVATION OF COSMIC-RAY ANISOTROPY WITH THE ICETOP AIR SHOWER ARRAY

Journal Article · Fri Mar 01 00:00:00 EST 2013 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/765/1/55· OSTI ID:22167604

Aartsen, M. G. ^[1]; Abbasi, R.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Baker, M. ^[2]; Abdou, Y. ^[3]; Ackermann, M. ^[4]; Adams, J. ^[5]; Aguilar, J. A. ^[6]; Altmann, D. ^[7]; Bai, X. ^[8]; Barwick, S. W. ^[9]; Baum, V. ^[10]; Bay, R. ^[11]; Beattie, K. ^[12]; Beatty, J. J. ^[13]; Bechet, S. ^[14]; Tjus, J. Becker ^[15]; Becker, K. -H. ^[16] ; others, and

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1. School of Chemistry and Physics, University of Adelaide, Adelaide, SA 5005 Australia (Australia)
2. Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States)
3. Department of Physics and Astronomy, University of Gent, B-9000 Gent (Belgium)
4. DESY, D-15735 Zeuthen (Germany)
5. Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand)
6. Departement de physique nucleaire et corpusculaire, Universite de Geneve, CH-1211 Geneve (Switzerland)
7. Institut fuer Physik, Humboldt-Universitaet zu Berlin, D-12489 Berlin (Germany)
8. Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)
9. Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States)
10. Institute of Physics, University of Mainz, Staudinger Weg 7, D-55099 Mainz (Germany)
11. Department of Physics, University of California, Berkeley, CA 94720 (United States)
12. Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)
13. Department of Physics and Center for Cosmology and Astro-Particle Physics, Ohio State University, Columbus, OH 43210 (United States)
14. Science Faculty CP230, Universite Libre de Bruxelles, B-1050 Brussels (Belgium)
15. Fakultaet fuer Physik and Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)
16. Department of Physics, University of Wuppertal, D-42119 Wuppertal (Germany)

We report on the observation of anisotropy in the arrival direction distribution of cosmic rays at PeV energies. The analysis is based on data taken between 2009 and 2012 with the IceTop air shower array at the south pole. IceTop, an integral part of the IceCube detector, is sensitive to cosmic rays between 100 TeV and 1 EeV. With the current size of the IceTop data set, searches for anisotropy at the 10{sup -3} level can, for the first time, be extended to PeV energies. We divide the data set into two parts with median energies of 400 TeV and 2 PeV, respectively. In the low energy band, we observe a strong deficit with an angular size of about 30 Degree-Sign and an amplitude of (- 1.58 {+-} 0.46{sub stat} {+-} 0.52{sub sys}) Multiplication-Sign 10{sup -3} at a location consistent with previous observations of cosmic rays with the IceCube neutrino detector. The study of the high energy band shows that the anisotropy persists to PeV energies and increases in amplitude to (- 3.11 {+-} 0.38{sub stat} {+-} 0.96{sub sys}) Multiplication-Sign 10{sup -3}.

• OSTI ID: 22167604
• Journal Information: Astrophysical Journal, Vol. 765, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ANGULAR DISTRIBUTION
ANISOTROPY
ANTARCTICA
ASTROPHYSICS
COSMIC NEUTRINOS
COSMIC RAY DETECTION
EEV RANGE
MULTIPARTICLE SPECTROMETERS
PARTICLE IDENTIFICATION
PEV RANGE
PRIMARY COSMIC RADIATION
SHOWER COUNTERS
TEV RANGE