Title

The Lateral Trigger Probability function for the ultra-high energy cosmic ray showers detected by 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
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
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, Max Planck Institute for Radio Astronomy
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

Document Type

Article

Publication Date

1-1-2011

Abstract

In this paper we introduce the concept of Lateral Trigger Probability (LTP) function, i.e., the probability for an Extensive Air Shower (EAS) to trigger an individual detector of a ground based array as a function of distance to the shower axis, taking into account energy, mass and direction of the primary cosmic ray. We apply this concept to the surface array of the Pierre Auger Observatory consisting of a 1.5 km spaced grid of about 1600 water Cherenkov stations. Using Monte Carlo simulations of ultra-high energy showers the LTP functions are derived for energies in the range between 1017 and 1019 eV and zenith angles up to 65°. A parametrization combining a step function with an exponential is found to reproduce them very well in the considered range of energies and zenith angles. The LTP functions can also be obtained from data using events simultaneously observed by the fluorescence and the surface detector of the Pierre Auger Observatory (hybrid events). We validate the Monte Carlo results showing how LTP functions from data are in good agreement with simulations. © 2011 Published by Elsevier B.V.

Publication Title

Astroparticle Physics

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