J. Abraham, Universidad Tecnologica Nacional
P. Abreu, Instituto Superior Técnico
M. Aglietta, Università degli Studi di Torino
C. Aguirre, Universidad Catolica de Bolivia
D. Allard, APC - AstroParticule et Cosmologie
I. Allekotte, Instituto Balseiro
J. Allen, New York University
P. Allison, The Ohio State University
C. Alvarez, Benemerita Universidad Autonoma de Puebla
J. Alvarez-Muñiz, Universidad de Santiago de Compostela
M. Ambrosio, Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
L. Anchordoqui, Northeastern University
S. Andringa, Instituto Superior Técnico
A. Anzalone, INAF Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo
C. Aramo, Istituto Nazionale di Fisica Nucleare, Sezione di Napoli
S. Argirò, Università degli Studi di Torino
K. Arisaka, University of California, Los Angeles
E. Armengaud, APC - AstroParticule et Cosmologie
F. Arneodo, Laboratori Nazionali del Gran Sasso
F. Arqueros, Universidad Complutense de Madrid
T. Asch, Karlsruher Institut für Technologie, Campus Nord
H. Asorey, Instituto Balseiro
P. Assis, Instituto Superior Técnico
B. S. Atulugama, Pennsylvania State University
J. Aublin, Laboratoire de Physique Nucléaire et de Hautes Energies
M. Ave, The Enrico Fermi Institute
G. Avila, Universidad Tecnologica Nacional
T. Bäcker, Universität Siegen
D. Badagnani, Universidad Nacional de La Plata
A. F. Barbosa, Centro Brasileiro de Pesquisas Físicas
D. Barnhill, University of California, Los Angeles
S. L.C. Barroso, Universidade Estadual do Sudoeste da Bahia
P. Bauleo, Colorado State University

Document Type


Publication Date



Using data collected at the Pierre Auger Observatory during the past 3.7 years, we demonstrated a correlation between the arrival directions of cosmic rays with energy above 6 × 1019 electron volts and the positions of active galactic nuclei (AGN) lying within ∼75 megaparsecs. We rejected the hypothesis of an isotropic distribution of these cosmic rays with at least a 99% confidence level from a prescribed a priori test. The correlation we observed is compatible with the hypothesis that the highest-energy particles originate from nearby extragalactic sources whose flux has not been substantially reduced by interaction with the cosmic background radiation. AGN or objects having a similar spatial distribution are possible sources.

Publication Source (Journal or Book title)


First Page


Last Page