Measurement of the cosmic ray spectrum above $4{\times}10^{18}$ eV using inclined events detected with the Pierre Auger Observatory

2015Mar
Authors: The Pierre Auger Collaboration, Alexander Aab, Pedro Abreu, Marco Aglietta, Eun-Joo Ahn, Imen Al Samarai, Ivone Albuquerque, Ingomar Allekotte, Patrick Allison, Alejandro Almela, Jesus Alvarez Castillo, Jaime Alvarez-Muñiz, Rafael Alves Batista, Michelangelo Ambrosio, Amin Aminaei, Luis Anchordoqui, Sofia Andringa, Carla Aramo, Victor Manuel Aranda, Fernando Arqueros, Nicusor Arsene, Hernán Gonzalo Asorey, Pedro Assis, Julien Aublin, Maximo Ave, Michel Avenier, Gualberto Avila, Nafiun Awal, Alina Mihaela Badescu, Kerri B Barber, Julia Bäuml, Colin Baus, Jim Beatty, Karl Heinz Becker, Jose A Bellido, Corinne Berat, Mario Edoardo Bertaina, Xavier Bertou, Peter Biermann, Pierre Billoir, Simon G Blaess, Alberto Blanco, Miguel Blanco, Carla Bleve, Hans Blümer, Martina Boháčová, Denise Boncioli, Carla Bonifazi, Nataliia Borodai, Jeffrey Brack, Iliana Brancus, Ariel Bridgeman, Pedro Brogueira, William C Brown, Peter Buchholz, Antonio Bueno, Stijn Buitink, Mario Buscemi, Karen S Caballero-Mora, Barbara Caccianiga, Lorenzo Caccianiga, Marina Candusso, Laurentiu Caramete, Rossella Caruso, Antonella Castellina, Gabriella Cataldi, Lorenzo Cazon, Rosanna Cester, Alan G Chavez, Andrea Chiavassa, Jose Augusto Chinellato, Jiri Chudoba, Marco Cilmo, Roger W Clay, Giuseppe Cocciolo, Roberta Colalillo, Alan Coleman, Laura Collica, Maria Rita Coluccia, Ruben Conceição, Fernando Contreras, Mathew J Cooper, Alain Cordier, Stephane Coutu, Corbin Covault, James Cronin, Richard Dallier, Bruno Daniel, Sergio Dasso, Kai Daumiller, Bruce R Dawson, Rogerio M de Almeida, Sijbrand J de Jong, Giuseppe De Mauro, Joao de Mello Neto, Ivan De Mitri, Jaime de Oliveira, Vitor de Souza, Luis del Peral, Olivier Deligny, Hans Dembinski, Niraj Dhital, Claudio Di Giulio, Armando Di Matteo, Johana Chirinos Diaz, Mary Lucia Díaz Castro, Francisco Diogo, Carola Dobrigkeit, Wendy Docters, Juan Carlos D'Olivo, Alexei Dorofeev, Qader Dorosti Hasankiadeh, Maria Teresa Dova, Jan Ebr, Ralph Engel, Martin Erdmann, Mona Erfani, Carlos O Escobar, Joao Espadanal, Alberto Etchegoyen, Heino Falcke, Ke Fang, Glennys Farrar, Anderson Fauth, Norberto Fazzini, Andrew P Ferguson, Mateus Fernandes, Brian Fick, Juan Manuel Figueira, Alberto Filevich, Andrej Filipčič, Brendan Fox, Octavian Fratu, Martín Miguel Freire, Benjamin Fuchs, Toshihiro Fujii, Beatriz García, Diego Garcia-Pinto, Florian Gate, Hartmut Gemmeke, Alexandru Gherghel-Lascu, Piera Luisa Ghia, Ugo Giaccari, Marco Giammarchi, Maria Giller, Dariusz Głas, Christian Glaser, Henry Glass, Geraldina Golup, Mariano Gómez Berisso, Primo F Gómez Vitale, Nicolás González, Ben Gookin, Jacob Gordon, Alessio Gorgi, Peter Gorham, Philippe Gouffon, Nathan Griffith, Aurelio Grillo, Trent D Grubb, Fausto Guarino, Germano Guedes, Matías Rolf Hampel, Patricia Hansen, Diego Harari, Thomas A Harrison, Sebastian Hartmann, John Harton, Andreas Haungs, Thomas Hebbeker, Dieter Heck, Philipp Heimann, Alexander E Herve, Gary C Hill, Carlos Hojvat, Nicholas Hollon, Ewa Holt, Piotr Homola, Jörg Hörandel, Pavel Horvath, Miroslav Hrabovský, Daniel Huber, Tim Huege, Antonio Insolia, Paula Gina Isar, Ingolf Jandt, Stefan Jansen, Cecilia Jarne, Jeffrey A Johnsen, Mariela Josebachuili, Alex Kääpä, Olga Kambeitz, Karl Heinz Kampert, Peter Kasper, Igor Katkov, Balazs Kégl, Bianca Keilhauer, Azadeh Keivani, Ernesto Kemp, Roger Kieckhafer, Hans Klages, Matthias Kleifges, Jonny Kleinfeller, Raphael Krause, Nicole Krohm, Oliver Krömer, Daniel Kuempel, Norbert Kunka, Danielle LaHurd, Luca Latronico, Robert Lauer, Markus Lauscher, Pascal Lautridou, Sandra Le Coz, Didier Lebrun, Paul Lebrun, Marcelo Augusto Leigui de Oliveira, Antoine Letessier-Selvon, Isabelle Lhenry-Yvon, Katrin Link, Luis Lopes, Rebeca López, Aida López Casado, Karim Louedec, Lu Lu, Agustin Lucero, Max Malacari, Simone Maldera, Manuela Mallamaci, Jennifer Maller, Dusan Mandat, Paul Mantsch, Analisa Mariazzi, Vincent Marin, Ioana Mariş, Giovanni Marsella, Daniele Martello, Lilian Martin, Humberto Martinez, Oscar Martínez Bravo, Diane Martraire, Jimmy Masías Meza, Hermann-Josef Mathes, Sebastian Mathys, James Matthews, John Matthews, Giorgio Matthiae, Detlef Maurel, Daniela Maurizio, Eric Mayotte, Peter Mazur, Carlos Medina, Gustavo Medina-Tanco, Rebecca Meissner, Victor Mello, Diego Melo, Alexander Menshikov, Stefano Messina, Rishi Meyhandan, Maria Isabel Micheletti, Lukas Middendorf, Ignacio A Minaya, Lino Miramonti, Bogdan Mitrica, Laura Molina-Bueno, Silvia Mollerach, François Montanet, Carlo Morello, Miguel Mostafá, Celio A Moura, Marcio Aparecido Muller, Gero Müller, Sarah Müller, Roberto Mussa, Gianni Navarra, Sergio Navas, Petr Necesal, Lukas Nellen, Anna Nelles, Jens Neuser, David Newton, Phong H Nguyen, Mihai Niculescu-Oglinzanu, Marcus Niechciol, Lukas Niemietz, Tim Niggemann, Dave Nitz, Dalibor Nosek, Vladimir Novotny, Lyberis Nožka, Livingstone Ochilo, Foteini Oikonomou, Angela Olinto, Victor Olmos-Gilbaja, Noelia Pacheco, Daniel Pakk Selmi-Dei, Miroslav Palatka, Juan Pallotta, Philipp Papenbreer, Gonzalo Parente, Alejandra Parra, Thomas Paul, Miroslav Pech, Jan Pękala, Rodrigo Pelayo, Iuri Pepe, Lorenzo Perrone, Emily Petermann, Christine Peters, Sergio Petrera, Yevgeniy Petrov, Jamyang Phuntsok, Ricardo Piegaia, Tanguy Pierog, Pablo Pieroni, Mário Pimenta, Valerio Pirronello, Manuel Platino, Matthias Plum, Alessio Porcelli, Czeslaw Porowski, Raul Ribeiro Prado, Paolo Privitera, Michael Prouza, Victor Purrello, Eduardo J Quel, Sven Querchfeld, Sean Quinn, Julian Rautenberg, Olivier Ravel, Diego Ravignani, Benoît Revenu, Jan Ridky, Simone Riggi, Markus Risse, Pablo Ristori, Vincenzo Rizi, Washington Rodrigues de Carvalho, Gonzalo Rodriguez Fernandez, Jorge Rubén Rodriguez Rojo, Maria Dolores Rodríguez-Frías, Dmytro Rogozin, Jaime Rosado, Markus Roth, Esteban Roulet, Adrian Rovero, Steven J Saffi, Alexandra Saftoiu, Francesco Salamida, Humberto Salazar, Ahmed Saleh, Francisco Salesa Greus, Gaetano Salina, Federico Sánchez, Patricia Sanchez-Lucas, Edivaldo Moura Santos, Eva Santos, Fred Sarazin, Biswaijt Sarkar, Raul Sarmento, Ricardo Sato, Carlos Scarso, Markus Schauer, Viviana Scherini, Harald Schieler, Peter Schiffer, David Schmidt, Olaf Scholten, Harm Schoorlemmer, Petr Schovánek, Frank G Schröder, Alexander Schulz, Johannes Schulz, Johannes Schumacher, Sergio Sciutto, Alberto Segreto, Mariangela Settimo, Amir Shadkam, Ronald C Shellard, Iván Sidelnik, Guenter Sigl, Octavian Sima, Andrzej Śmiałkowski, Radomir Šmída, Gregory Snow, Paul Sommers, J Sorokin, Ruben Squartini, Yogendra N Srivastava, Denis Stanca, Samo Stanič, James Stapleton, Jaroslaw Stasielak, Maurice Stephan, Anne Stutz, Federico Suarez, Tiina Suomijärvi, A Daniel Supanitsky, Michael Sutherland, John Swain, Zbigniew Szadkowski, Oscar Alejandro Taborda, Alex Tapia, Andreas Tepe, Vanessa Menezes Theodoro, Charles Timmermans, Carlos J Todero Peixoto, Gabriel Toma, Lenka Tomankova, Bernardo Tomé, Aurelio Tonachini, Guillermo Torralba Elipe, Diego Torres Machado, Petr Travnicek, Ralf Ulrich, Michael Unger, Martin Urban, Jose F Valdés Galicia, Ines Valiño, Laura Valore, Guus van Aar, Patrick van Bodegom, Ad M van den Berg, Sjoert van Velzen, Arjen van Vliet, Enrique Varela, Bernardo Vargas Cárdenas, Gary Varner, Rafael Vasquez, Jose R Vázquez, Ricardo Vázquez, Darko Veberič, Valerio Verzi, Jakub Vicha, Mariela Videla, Luis Villaseñor, Brian Vlcek, Serguei Vorobiov, Hernan Wahlberg, Oscar Wainberg, David Walz, Alan Watson, Marc Weber, Klaus Weidenhaupt, Andreas Weindl, Felix Werner, Allan Widom, Lawrence Wiencke, Henryk Wilczyński, Tobias Winchen, David Wittkowski, Brian Wundheiler, Sarka Wykes, Lili Yang, Tolga Yapici, Alexey Yushkov, Enrique Zas, Danilo Zavrtanik, Marko Zavrtanik, Arnulfo Zepeda, Yue Zhu, Benedikt Zimmermann, Michael Ziolkowski, Francesca Zuccarello

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.

Comments: Replaced with published version. Added journal reference and DOI

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