Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 × 1018 eV

Pierre Auger Collaboration

doi:10.1126/science.aan4338

Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 × 10¹⁸ eV

Pierre Auger Collaboration

Physics

Radboud University Nijmegen
Instituto Superior Tecnico
INAF-IAPS
Sezione di Torino
Laboratoire de Physique Nucléaire et de Hautes Energies
University of São Paulo
CNEA-UNCuyo-CONICET
UNSAM
Universidad Tecnológica Nacional
Universidad Nacional Autonoma de Mexico
Universidad de Santiago de Compostela
Gran Sasso Science Institute
Laboratori Nazionali del Gran Sasso
Lehman College
Sezione di Napoli
Universidad Complutense de Madrid
Institute of Space Sciences
Universidad Industrial de Santander
Observatorio Pierre Auger and Comisión Nacional de Energía Atómica
University Politehnica of Bucharest
'Horia Hulubei' National Institute for Physics and Nuclear Engineering
Università di Napoli 'Federico II' and Sezione INFN
Ohio State University
Bergische Universität Wuppertal
University of Adelaide
UJF-Grenoble 1/CNRS-INSU
Università di Torino and Sezione INFN
Max-Planck-Institut für Radioastronomie
Université Paris 11
Institute of Physics of the Czech Academy of Sciences
Universita del Salento
Sezione di Lecce
Deutsches Elektronen-Synchrotron (DESY)
Universidade Federal do Rio de Janeiro
Institute of Nuclear Physics PAN
Karlsruhe Institute of Technology (KIT)
Colorado State University
RWTH Aachen University
Universität Siegen
Universidad de Granada

Research output: Contribution to journal › Article › peer-review

408 Scopus citations

Abstract

Cosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come from studying the distribution of their arrival directions. Using 3 × 10⁴ cosmic rays with energies above 8 × 101⁸ electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 km² sr year, we determined the existence of anisotropy in arrival directions. The anisotropy, detected at more than a 5.2σ level of significance, can be described by a dipole with an amplitude of 6.5+^1.3 _-0.9 percent toward right ascension α_d = 100 ± 10 degrees and declination δ_d = -24⁺¹² _-13 degrees. That direction indicates an extragalactic origin for these ultrahighenergy particles.

Original language	British English
Pages (from-to)	1266-1270
Number of pages	5
Journal	Science
Volume	357
Issue number	6357
DOIs	https://doi.org/10.1126/science.aan4338
State	Published - 22 Sep 2017

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@article{00218cf1af3f4c22aecf5206f5d471db,

title = "Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 × 1018 eV",

abstract = "Cosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come from studying the distribution of their arrival directions. Using 3 × 104 cosmic rays with energies above 8 × 1018 electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 km2 sr year, we determined the existence of anisotropy in arrival directions. The anisotropy, detected at more than a 5.2σ level of significance, can be described by a dipole with an amplitude of 6.5+1.3 -0.9 percent toward right ascension αd = 100 ± 10 degrees and declination δd = -24+12 -13 degrees. That direction indicates an extragalactic origin for these ultrahighenergy particles.",

author = "\{Pierre Auger Collaboration\} and A. Aab and P. Abreu and M. Aglietta and Samarai, \{I. Al\} and Albuquerque, \{I. F.M.\} and I. Allekotte and A. Almela and Castillo, \{J. Alvarez\} and J. Alvarez-Mu{\~n}iz and Anastasi, \{G. A.\} and L. Anchordoqui and B. Andrada and S. Andringa and C. Aramo and F. Arqueros and N. Arsene and H. Asorey and P. Assis and J. Aublin and G. Avila and Badescu, \{A. M.\} and A. Balaceanu and F. Barbato and Luz, \{R. J.Barreira\} and Beatty, \{J. J.\} and Becker, \{K. H.\} and Bellido, \{J. A.\} and C. Berat and Bertaina, \{M. E.\} and X. Bertou and Biermann, \{P. L.\} and P. Billoir and J. Biteau and Blaess, \{S. G.\} and A. Blanco and J. Blazek and C. Bleve and M. Boh{\'a}cov{\'a} and D. Boncioli and C. Bonifazi and N. Borodai and Botti, \{A. M.\} and J. Brack and I. Brancus and T. Bretz and A. Bridgeman and Briechle, \{F. L.\} and P. Buchholz and A. Bueno and \{Van Vliet\}, A.",

year = "2017",

month = sep,

day = "22",

doi = "10.1126/science.aan4338",

language = "British English",

volume = "357",

pages = "1266--1270",

journal = "Science",

issn = "0036-8075",

publisher = "American Association for the Advancement of Science",

number = "6357",

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TY - JOUR

T1 - Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 × 1018 eV

AU - Pierre Auger Collaboration

AU - Aab, A.

AU - Abreu, P.

AU - Aglietta, M.

AU - Samarai, I. Al

AU - Albuquerque, I. F.M.

AU - Allekotte, I.

AU - Almela, A.

AU - Castillo, J. Alvarez

AU - Alvarez-Muñiz, J.

AU - Anastasi, G. A.

AU - Anchordoqui, L.

AU - Andrada, B.

AU - Andringa, S.

AU - Aramo, C.

AU - Arqueros, F.

AU - Arsene, N.

AU - Asorey, H.

AU - Assis, P.

AU - Aublin, J.

AU - Avila, G.

AU - Badescu, A. M.

AU - Balaceanu, A.

AU - Barbato, F.

AU - Luz, R. J.Barreira

AU - Beatty, J. J.

AU - Becker, K. H.

AU - Bellido, J. A.

AU - Berat, C.

AU - Bertaina, M. E.

AU - Bertou, X.

AU - Biermann, P. L.

AU - Billoir, P.

AU - Biteau, J.

AU - Blaess, S. G.

AU - Blanco, A.

AU - Blazek, J.

AU - Bleve, C.

AU - Bohácová, M.

AU - Boncioli, D.

AU - Bonifazi, C.

AU - Borodai, N.

AU - Botti, A. M.

AU - Brack, J.

AU - Brancus, I.

AU - Bretz, T.

AU - Bridgeman, A.

AU - Briechle, F. L.

AU - Buchholz, P.

AU - Bueno, A.

AU - Van Vliet, A.

PY - 2017/9/22

Y1 - 2017/9/22

N2 - Cosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come from studying the distribution of their arrival directions. Using 3 × 104 cosmic rays with energies above 8 × 1018 electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 km2 sr year, we determined the existence of anisotropy in arrival directions. The anisotropy, detected at more than a 5.2σ level of significance, can be described by a dipole with an amplitude of 6.5+1.3 -0.9 percent toward right ascension αd = 100 ± 10 degrees and declination δd = -24+12 -13 degrees. That direction indicates an extragalactic origin for these ultrahighenergy particles.

AB - Cosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come from studying the distribution of their arrival directions. Using 3 × 104 cosmic rays with energies above 8 × 1018 electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 km2 sr year, we determined the existence of anisotropy in arrival directions. The anisotropy, detected at more than a 5.2σ level of significance, can be described by a dipole with an amplitude of 6.5+1.3 -0.9 percent toward right ascension αd = 100 ± 10 degrees and declination δd = -24+12 -13 degrees. That direction indicates an extragalactic origin for these ultrahighenergy particles.

UR - https://www.scopus.com/pages/publications/85029867353

U2 - 10.1126/science.aan4338

DO - 10.1126/science.aan4338

M3 - Article

C2 - 28935800

AN - SCOPUS:85029867353

SN - 0036-8075

VL - 357

SP - 1266

EP - 1270

JO - Science

JF - Science

IS - 6357

ER -

Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 × 10¹⁸ eV

Abstract

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