Atmospheric effects on extensive air showers observed with the surface detector of the Pierre Auger observatory

Authors

J. Abraham, Consejo Nacional de Investigaciones Científicas y Técnicas
P. Abreu, Instituto Superior Técnico
M. Aglietta, Università degli Studi di Torino
C. Aguirre, Universidad Catolica de Bolivia
E. J. Ahn, Fermi National Accelerator Laboratory
D. Allard, APC - AstroParticule et Cosmologie
I. Allekotte, Instituto Balseiro
J. Allen, New York University
P. Allison, The Ohio State University
J. Alvarez-Muñiz, Universidad de Santiago de Compostela
M. Ambrosio, Università degli Studi di Napoli Federico II
L. Anchordoqui, University of Wisconsin-Milwaukee
S. Andringa, Instituto Superior Técnico
A. Anzalone, INAF Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo
C. Aramo, Università degli Studi di Napoli Federico II
E. Arganda, Universidad Complutense de Madrid
S. Argirò, Università degli Studi di Torino
K. Arisaka, University of California, Los Angeles
F. Arneodo, Laboratori Nazionali del Gran Sasso
F. Arqueros, Universidad Complutense de Madrid
T. Asch, Karlsruhe Institute of Technology, Campus North
H. Asorey, Instituto Balseiro
P. Assis, Instituto Superior Técnico
J. Aublin, Laboratoire de Physique Nucléaire et de Hautes Energies
M. Ave, The Enrico Fermi Institute
G. Avila, Pierre Auger Observatory
T. Bäcker, Universität Siegen
D. Badagnani, Universidad Nacional de La Plata
K. B. Barber, The University of Adelaide
A. F. Barbosa, Centro Brasileiro de Pesquisas Físicas
S. L.C. Barroso, Universidade Estadual do Sudoeste da Bahia
B. Baughman, The Ohio State University

Document Type

Article

Publication Date

1-1-2009

Abstract

Atmospheric parameters, such as pressure (P), temperature (T) and density (ρ ∝ P / T), affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ∼ 10 % seasonal modulation and ∼ 2 % diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of P and ρ. The former affects the longitudinal development of air showers while the latter influences the Molière radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory. © 2009 Elsevier B.V. All rights reserved.

Publication Title

Astroparticle Physics

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