Observation of anisotropy in the galactic cosmic-ray arrival directions at 400 TeV with IceCube

IceCube Collaboration

Research output: Contribution to journalArticle

109 Citations (Scopus)

Abstract

In this paper we report the first observation in the Southern hemisphere of an energy dependence in the Galactic cosmic-ray anisotropy up to a few hundred TeV. This measurement was performed using cosmic-ray-induced muons recorded by the partially deployed IceCube observatory between 2009 May and 2010 May. The data include a total of 33 × 109 muon events with a median angular resolution of ∼3°. A sky map of the relative intensity in arrival direction over the Southern celestial sky is presented for cosmic-ray median energies of 20 and 400 TeV. The same large-scale anisotropy observed at median energies around 20 TeV is not present at 400 TeV. Instead, the high-energy sky map shows a different anisotropy structure including a deficit with a post-trial significance of .6.3σ. This anisotropy reveals a new feature of the Galactic cosmic-ray distribution, which must be incorporated into theories of the origin and propagation of cosmic rays.

Original languageEnglish (US)
Article number33
JournalAstrophysical Journal
Volume746
Issue number1
DOIs
StatePublished - Feb 10 2012

Fingerprint

cosmic ray
arrivals
anisotropy
sky
cosmic rays
muons
energy
Southern Hemisphere
angular resolution
observatories
observatory
propagation

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

@article{ee0fe63c8b0343278f782c45f48bbcca,
title = "Observation of anisotropy in the galactic cosmic-ray arrival directions at 400 TeV with IceCube",
abstract = "In this paper we report the first observation in the Southern hemisphere of an energy dependence in the Galactic cosmic-ray anisotropy up to a few hundred TeV. This measurement was performed using cosmic-ray-induced muons recorded by the partially deployed IceCube observatory between 2009 May and 2010 May. The data include a total of 33 × 109 muon events with a median angular resolution of ∼3°. A sky map of the relative intensity in arrival direction over the Southern celestial sky is presented for cosmic-ray median energies of 20 and 400 TeV. The same large-scale anisotropy observed at median energies around 20 TeV is not present at 400 TeV. Instead, the high-energy sky map shows a different anisotropy structure including a deficit with a post-trial significance of .6.3σ. This anisotropy reveals a new feature of the Galactic cosmic-ray distribution, which must be incorporated into theories of the origin and propagation of cosmic rays.",
author = "{IceCube Collaboration} and R. Abbasi and Y. Abdou and T. Abu-Zayyad and M. Ackermann and J. Adams and Aguilar, {J. A.} and M. Ahlers and Allen, {M. M.} and D. Altmann and K. Andeen and J. Auffenberg and X. Bai and M. Baker and Barwick, {S. W.} and R. Bay and {Bazo Alba}, {J. L.} and K. Beattie and Beatty, {J. J.} and S. Bechet and Becker, {J. K.} and Becker, {K. H.} and Benabderrahmane, {M. L.} and S. BenZvi and J. Berdermann and P. Berghaus and D. Berley and E. Bernardini and D. Bertrand and Besson, {D. Z.} and D. Bindig and M. Bissok and E. Blaufuss and J. Blumenthal and Boersma, {D. J.} and C. Bohm and D. Bose and S. B{\"o}ser and O. Botner and Brown, {A. M.} and S. Buitink and Caballero-Mora, {K. S.} and M. Carson and D. Chirkin and B. Christy and F. Clevermann and S. Cohen and C. Colnard and Cowen, {D. F.} and Douglas Cowen and Meszaros, {Peter Istvan}",
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Observation of anisotropy in the galactic cosmic-ray arrival directions at 400 TeV with IceCube. / IceCube Collaboration.

In: Astrophysical Journal, Vol. 746, No. 1, 33, 10.02.2012.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Observation of anisotropy in the galactic cosmic-ray arrival directions at 400 TeV with IceCube

AU - IceCube Collaboration

AU - Abbasi, R.

AU - Abdou, Y.

AU - Abu-Zayyad, T.

AU - Ackermann, M.

AU - Adams, J.

AU - Aguilar, J. A.

AU - Ahlers, M.

AU - Allen, M. M.

AU - Altmann, D.

AU - Andeen, K.

AU - Auffenberg, J.

AU - Bai, X.

AU - Baker, M.

AU - Barwick, S. W.

AU - Bay, R.

AU - Bazo Alba, J. L.

AU - Beattie, K.

AU - Beatty, J. J.

AU - Bechet, S.

AU - Becker, J. K.

AU - Becker, K. H.

AU - Benabderrahmane, M. L.

AU - BenZvi, S.

AU - Berdermann, J.

AU - Berghaus, P.

AU - Berley, D.

AU - Bernardini, E.

AU - Bertrand, D.

AU - Besson, D. Z.

AU - Bindig, D.

AU - Bissok, M.

AU - Blaufuss, E.

AU - Blumenthal, J.

AU - Boersma, D. J.

AU - Bohm, C.

AU - Bose, D.

AU - Böser, S.

AU - Botner, O.

AU - Brown, A. M.

AU - Buitink, S.

AU - Caballero-Mora, K. S.

AU - Carson, M.

AU - Chirkin, D.

AU - Christy, B.

AU - Clevermann, F.

AU - Cohen, S.

AU - Colnard, C.

AU - Cowen, D. F.

AU - Cowen, Douglas

AU - Meszaros, Peter Istvan

PY - 2012/2/10

Y1 - 2012/2/10

N2 - In this paper we report the first observation in the Southern hemisphere of an energy dependence in the Galactic cosmic-ray anisotropy up to a few hundred TeV. This measurement was performed using cosmic-ray-induced muons recorded by the partially deployed IceCube observatory between 2009 May and 2010 May. The data include a total of 33 × 109 muon events with a median angular resolution of ∼3°. A sky map of the relative intensity in arrival direction over the Southern celestial sky is presented for cosmic-ray median energies of 20 and 400 TeV. The same large-scale anisotropy observed at median energies around 20 TeV is not present at 400 TeV. Instead, the high-energy sky map shows a different anisotropy structure including a deficit with a post-trial significance of .6.3σ. This anisotropy reveals a new feature of the Galactic cosmic-ray distribution, which must be incorporated into theories of the origin and propagation of cosmic rays.

AB - In this paper we report the first observation in the Southern hemisphere of an energy dependence in the Galactic cosmic-ray anisotropy up to a few hundred TeV. This measurement was performed using cosmic-ray-induced muons recorded by the partially deployed IceCube observatory between 2009 May and 2010 May. The data include a total of 33 × 109 muon events with a median angular resolution of ∼3°. A sky map of the relative intensity in arrival direction over the Southern celestial sky is presented for cosmic-ray median energies of 20 and 400 TeV. The same large-scale anisotropy observed at median energies around 20 TeV is not present at 400 TeV. Instead, the high-energy sky map shows a different anisotropy structure including a deficit with a post-trial significance of .6.3σ. This anisotropy reveals a new feature of the Galactic cosmic-ray distribution, which must be incorporated into theories of the origin and propagation of cosmic rays.

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U2 - 10.1088/0004-637X/746/1/33

DO - 10.1088/0004-637X/746/1/33

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JF - Astrophysical Journal

SN - 0004-637X

IS - 1

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