Title

Search for first harmonic modulation in the right ascension distribution of cosmic rays detected at the Pierre Auger Observatory

Authors

P. Abreu, Instituto Superior Técnico
M. Aglietta, Università degli Studi di Torino
E. J. Ahn, Fermi National Accelerator Laboratory
I. F.M. Albuquerque, Universidade de Sao Paulo - USP
D. Allard, APC - AstroParticule et Cosmologie
I. Allekotte, Centro Atomico Bariloche
J. Allen, New York University
P. Allison, The Ohio State University
J. Alvarez Castillo, Universidad Nacional Autónoma de México
J. Alvarez-Muñiz, Universidad de Santiago de Compostela
M. Ambrosio, Università degli Studi di Napoli Federico II
A. Aminaei, Radboud University Nijmegen
L. Anchordoqui, University of Wisconsin-Milwaukee
S. Andringa, Instituto Superior Técnico
T. Antičić, Institute Ruder Boskovic
C. Aramo, Università degli Studi di Napoli Federico II
E. Arganda, Universidad Complutense de Madrid
F. Arqueros, Universidad Complutense de Madrid
H. Asorey, Centro Atomico Bariloche
P. Assis, Instituto Superior Técnico
J. Aublin, Laboratoire de Physique Nucléaire et de Hautes Energies
M. Ave, Karlsruhe Institute of Technology, Campus North
M. Avenier, Laboratoire de Physique Subatomique et de Cosmologie de Grenoble
G. Avila, Pierre Auger Observatory
T. Bäcker, Universität Siegen
M. Balzer, Karlsruhe Institute of Technology
K. B. Barber, The University of Adelaide
A. F. Barbosa, Centro Brasileiro de Pesquisas Físicas
R. Bardenet, Laboratoire de l'Accélérateur Linéaire
S. L.C. Barroso, Universidade Estadual do Sudoeste da Bahia
B. Baughman, The Ohio State University
J. J. Beatty, The Ohio State University

Document Type

Article

Publication Date

1-1-2011

Abstract

We present the results of searches for dipolar-type anisotropies in different energy ranges above 2.5 × 1017 eV with the surface detector array of the Pierre Auger Observatory, reporting on both the phase and the amplitude measurements of the first harmonic modulation in the right-ascension distribution. Upper limits on the amplitudes are obtained, which provide the most stringent bounds at present, being below 2% at 99% C.L. for EeV energies. We also compare our results to those of previous experiments as well as with some theoretical expectations. © 2011 Published by Elsevier B.V.

Publication Title

Astroparticle Physics

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