Publication: The effect of the geomagnetic field on cosmic ray energy estimates and large scale anisotropy searches on data from the Pierre Auger Observatory
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2011-11
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IOP Publishing
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Abstract
We present a comprehensive study of the influence of the geomagnetic field on the energy estimation of extensive air showers with a zenith angle smaller than 60 degrees, detected at the Pierre Auger Observatory. the geomagnetic field induces an azimuthal modulation of the estimated energy of cosmic rays up to the similar to 2% level at large zenith angles. We present a method to account for this modulation of the reconstructed energy. We analyse the effect of the modulation on large scale anisotropy searches in the arrival direction distributions of cosmic rays. At a given energy, the geomagnetic effect is shown to induce a pseudo-dipolar pattern at the percent level in the declination distribution that needs to be accounted for.
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© 2011 IOP Publishing Ltd and SISSA.
Artículo firmado por más de 10 autores, (Pierre Auger Observatory).
We are very grateful to the following agencies and organizations for financial support: Comision Nacional de Energia Atomica, Fundacion Antorchas, Gobierno De La Provincia de Mendoza, Municipalidad de Malargue, NDM Holdings and Valle Las Lenas, in gratitude for their continuing cooperation over land access, Argentina; the Australian Research Council; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundacao de Amparo a Pesquisa do Estado de Rio de Janeiro (FAPERJ), Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Ministerio de Ciencia e Tecnologia (MCT), Brazil; AVCR AV0Z10.100502 and AV0Z10100522, GAAV KJB100100904, MSMT-CR LA08016, LC527, 1M06002, and MSN10021620859, Czech Republic; Centre de Calcul IN2P3/CNRS, Centre National de la Recherche,. Scientifique (CNRS). Conseil Regional Ile-de-France, Departement Physique Nucleaire et Corpusculaire (PNC-IN2P3/CNRS), Departement Sciences de l'Univers (SDU-INSU/CNR.S), France; Bundesministerium far Bildung mid Forschung (BMBF), Deutsche Forschungsgenteinschaft (DFG), Finanzministerium Baden-Wurttemberg, Helmholtz-Gemeinschaft Deutscher Forschungszentren (HGF), Ministerium fur Wissenschaft und Forschung, Nordrhein-Westfalen, Ministerium fur Wissenschaft, Forschung und Kunst, Liaden-Wurttemberg, Germany; Istituto Nazionale di Fisica Nucleate Ministero dell'Istruzione, dell'Universita e della Ricerca (MIUR), Italy; Consejo Nacional de Ciencia y Tecnologia (CONACYT), Mexico; Ministerie van Onderwijs, Cultuur en Wetenschap, Nederlandse Organisatie voor \\Tetenschappelijk Onderzoek (NNVO), Stichting voor Rindamenteel Onderzoelc der Materie (FOM), Netherlands; Ministry of Science and Higher Education, Grant Nos. IN N202 200239 and N N202 207238, Poland; Fundacao para a Ciencia e a 'Tecnologia, Portugal; Ministry for Higher Education, Science, and Technology, Slovenian Research Agency, Slovenia; Comunidad de Madrid, Consejerfa de Educacion de la Comunidad de Castilla La Mancha, FEDER funds, Ministerio de Ciencia e Innovacion and Consolider-Ingenio 2010 (CPAN), Xunta de Galicia, Spain; Science and Technology Facilities Council, United Kingdom; Department of Energy, Contract Nos. DE-AC02-07CH11359, DE-FR02-04ER41300, National Science Foundation, Grant No. 0450696, The Grainger Foundation USA; ALFA-EC / HELEN, European Union 6th Framework Program, Grant No. MEIF-CT-2005-025057, European Union 7th Framework Program, Grant No. PIEF-GA-2008-220240 and UNESCO.
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