Observation of a Large-scale Anisotropy in the Arrival Directions of Cosmic Rays above $8 \times 10^{18}$ eV
Creators: name: The Pierre Auger Collaboration
name: Aab, A.
name: Abreu, P.
name: Aglietta, M.
name: Samarai, I. Al
name: Albuquerque, I. F. M.
name: Allekotte, I.
name: Almela, A.
name: Castillo, J. Alvarez
name: Alvarez-Muñiz, J.
name: Anastasi, G. A.
name: Anchordoqui, L.
name: Andrada, B.
name: Andringa, S.
name: Aramo, C.
name: Arqueros, F.
name: Arsene, N.
name: Asorey, H.
name: Assis, P.
name: Aublin, J.
name: Avila, G.
name: Badescu, A. M.
name: Balaceanu, A.
name: Barbato, F.
name: Luz, R. J. Barreira
name: Beatty, J. J.
name: Becker, K. H.
name: Bellido, J. A.
name: Berat, C.
name: Bertaina, M. E.
name: Bertou, X.
name: Biermann, P. L.
name: Billoir, P.
name: Biteau, J.
name: Blaess, S. G.
name: Blanco, A.
name: Blazek, J.
name: Bleve, C.
name: Boháčová, M.
name: Boncioli, D.
name: Bonifazi, C.
name: Borodai, N.
name: Botti, A. M.
name: Brack, J.
name: Brancus, I.
name: Bretz, T.
name: Bridgeman, A.
name: Briechle, F. L.
name: Buchholz, P.
name: Bueno, A.
name: Buitink, S.
name: Buscemi, M.
name: Caballero-Mora, K. S.
name: Caccianiga, L.
name: Cancio, A.
name: Canfora, F.
name: Caramete, L.
name: Caruso, R.
name: Castellina, A.
name: Cataldi, G.
name: Cazon, L.
name: Chavez, A. G.
name: Chinellato, J. A.
name: Chudoba, J.
name: Clay, R. W.
name: Cobos, A.
name: Colalillo, R.
name: Coleman, A.
name: Collica, L.
name: Coluccia, M. R.
name: Conceição, R.
name: Consolati, G.
name: Contreras, F.
name: Cooper, M. J.
name: Coutu, S.
name: Covault, C. E.
name: Cronin, J.
name: D'Amico, S.
name: Daniel, B.
name: Dasso, S.
name: Daumiller, K.
name: Dawson, B. R.
name: de Almeida, R. M.
name: de Jong, S. J.
name: De Mauro, G.
name: Neto, J. R. T. de Mello
name: De Mitri, I.
name: de Oliveira, J.
name: de Souza, V.
name: Debatin, J.
name: Deligny, O.
name: Di Giulio, C.
name: Di Matteo, A.
name: Castro, M. L. Díaz
name: Diogo, F.
name: Dobrigkeit, C.
name: D'Olivo, J. C.
name: Dorosti, Q.
name: Anjos, R. C. dos
name: Dova, M. T.
name: Dundovic, A.
name: Ebr, J.
name: Engel, R.
name: Erdmann, M.
name: Erfani, M.
name: Escobar, C. O.
name: Espadanal, J.
name: Etchegoyen, A.
name: Falcke, H.
name: Farrar, G.
name: Fauth, A. C.
name: Fazzini, N.
name: Fenu, F.
name: Fick, B.
name: Figueira, J. M.
name: Filipčič, A.
name: Fratu, O.
name: Freire, M. M.
name: Fujii, T.
name: Fuster, A.
name: Gaior, R.
name: García, B.
name: Garcia-Pinto, D.
name: Gaté, F.
name: Gemmeke, H.
name: Gherghel-Lascu, A.
name: Ghia, P. L.
name: Giaccari, U.
name: Giammarchi, M.
name: Giller, M.
name: Głas, D.
name: Glaser, C.
name: Golup, G.
name: Berisso, M. Gómez
name: Vitale, P. F. Gómez
name: González, N.
name: Gorgi, A.
name: Gorham, P.
name: Grillo, A. F.
name: Grubb, T. D.
name: Guarino, F.
name: Guedes, G. P.
name: Hampel, M. R.
name: Hansen, P.
name: Harari, D.
name: Harrison, T. A.
name: Harton, J. L.
name: Haungs, A.
name: Hebbeker, T.
name: Heck, D.
name: Heimann, P.
name: Herve, A. E.
name: Hill, G. C.
name: Hojvat, C.
name: Holt, E.
name: Homola, P.
name: Hörandel, J. R.
name: Horvath, P.
name: Hrabovský, M.
name: Huege, T.
name: Hulsman, J.
name: Insolia, A.
name: Isar, P. G.
name: Jandt, I.
name: Jansen, S.
name: Johnsen, J. A.
name: Josebachuili, M.
name: Jurysek, J.
name: Kääpä, A.
name: Kambeitz, O.
name: Kampert, K. H.
name: Katkov, I.
name: Keilhauer, B.
name: Kemmerich, N.
name: Kemp, E.
name: Kemp, J.
name: Kieckhafer, R. M.
name: Klages, H. O.
name: Kleifges, M.
name: Kleinfeller, J.
name: Krause, R.
name: Krohm, N.
name: Kuempel, D.
name: Mezek, G. Kukec
name: Kunka, N.
name: Awad, A. Kuotb
name: LaHurd, D.
name: Lauscher, M.
name: Legumina, R.
name: de Oliveira, M. A. Leigui
name: Letessier-Selvon, A.
name: Lhenry-Yvon, I.
name: Link, K.
name: Presti, D. Lo
name: Lopes, L.
name: López, R.
name: Casado, A. López
name: Luce, Q.
name: Lucero, A.
name: Malacari, M.
name: Mallamaci, M.
name: Mandat, D.
name: Mantsch, P.
name: Mariazzi, A. G.
name: Mariş, I. C.
name: Marsella, G.
name: Martello, D.
name: Martinez, H.
name: Bravo, O. Martínez
name: Meza, J. J. Masías
name: Mathes, H. J.
name: Mathys, S.
name: Matthews, J.
name: Matthews, J. A. J.
name: Matthiae, G.
name: Mayotte, E.
name: Mazur, P. O.
name: Medina, C.
name: Medina-Tanco, G.
name: Melo, D.
name: Menshikov, A.
name: Merenda, K. -D.
name: Michal, S.
name: Micheletti, M. I.
name: Middendorf, L.
name: Miramonti, L.
name: Mitrica, B.
name: Mockler, D.
name: Mollerach, S.
name: Montanet, F.
name: Morello, C.
name: Mostafá, M.
name: Müller, A. L.
name: Müller, G.
name: Muller, M. A.
name: Müller, S.
name: Mussa, R.
name: Naranjo, I.
name: Nellen, L.
name: Nguyen, P. H.
name: Niculescu-Oglinzanu, M.
name: Niechciol, M.
name: Niemietz, L.
name: Niggemann, T.
name: Nitz, D.
name: Nosek, D.
name: Novotny, V.
name: Nožka, L.
name: Núñez, L. A.
name: Ochilo, L.
name: Oikonomou, F.
name: Olinto, A.
name: Palatka, M.
name: Pallotta, J.
name: Papenbreer, P.
name: Parente, G.
name: Parra, A.
name: Paul, T.
name: Pech, M.
name: Pedreira, F.
name: Pękala, J.
name: Pelayo, R.
name: Peña-Rodriguez, J.
name: Pereira, L. A. S.
name: Perlín, M.
name: Perrone, L.
name: Peters, C.
name: Petrera, S.
name: Phuntsok, J.
name: Piegaia, R.
name: Pierog, T.
name: Pieroni, P.
name: Pimenta, M.
name: Pirronello, V.
name: Platino, M.
name: Plum, M.
name: Porowski, C.
name: Prado, R. R.
name: Privitera, P.
name: Prouza, M.
name: Quel, E. J.
name: Querchfeld, S.
name: Quinn, S.
name: Ramos-Pollan, R.
name: Rautenberg, J.
name: Ravignani, D.
name: Revenu, B.
name: Ridky, J.
name: Riehn, F.
name: Risse, M.
name: Ristori, P.
name: Rizi, V.
name: de Carvalho, W. Rodrigues
name: Fernandez, G. Rodriguez
name: Rojo, J. Rodriguez
name: Rogozin, D.
name: Roncoroni, M. J.
name: Roth, M.
name: Roulet, E.
name: Rovero, A. C.
name: Ruehl, P.
name: Saffi, S. J.
name: Saftoiu, A.
name: Salamida, F.
name: Salazar, H.
name: Saleh, A.
name: Greus, F. Salesa
name: Salina, G.
name: Sánchez, F.
name: Sanchez-Lucas, P.
name: Santos, E. M.
name: Santos, E.
name: Sarazin, F.
name: Sarmento, R.
name: Sarmiento, C. A.
name: Sato, R.
name: Schauer, M.
name: Scherini, V.
name: Schieler, H.
name: Schimp, M.
name: Schmidt, D.
name: Scholten, O.
name: Schovánek, P.
name: Schröder, F. G.
name: Schulz, A.
name: Schumacher, J.
name: Sciutto, S. J.
name: Segreto, A.
name: Settimo, M.
name: Shadkam, A.
name: Shellard, R. C.
name: Sigl, G.
name: Silli, G.
name: Sima, O.
name: Śmiałkowski, A.
name: Šmída, R.
name: Snow, G. R.
name: Sommers, P.
name: Sonntag, S.
name: Sorokin, J.
name: Squartini, R.
name: Stanca, D.
name: Stanič, S.
name: Stasielak, J.
name: Stassi, P.
name: Strafella, F.
name: Suarez, F.
name: Durán, M. Suarez
name: Sudholz, T.
name: Suomijärvi, T.
name: Supanitsky, A. D.
name: Šupík, J.
name: Swain, J.
name: Szadkowski, Z.
name: Taboada, A.
name: Taborda, O. A.
name: Tapia, A.
name: Theodoro, V. M.
name: Timmermans, C.
name: Peixoto, C. J. Todero
name: Tomankova, L.
name: Tomé, B.
name: Elipe, G. Torralba
name: Travnicek, P.
name: Trini, M.
name: Ulrich, R.
name: Unger, M.
name: Urban, M.
name: Galicia, J. F. Valdés
name: Valiño, I.
name: Valore, L.
name: van Aar, G.
name: van Bodegom, P.
name: Berg, A. M. van den
name: van Vliet, A.
name: Varela, E.
name: Cárdenas, B. Vargas
name: Varner, G.
name: Vázquez, R. A.
name: Veberič, D.
name: Ventura, C.
name: Quispe, I. D. Vergara
name: Verzi, V.
name: Vicha, J.
name: Villaseñor, L.
name: Vorobiov, S.
name: Wahlberg, H.
name: Wainberg, O.
name: Walz, D.
name: Watson, A. A.
name: Weber, M.
name: Weindl, A.
name: Wiencke, L.
name: Wilczyński, H.
name: Wirtz, M.
name: Wittkowski, D.
name: Wundheiler, B.
name: Yang, L.
name: Yushkov, A.
name: Zas, E.
name: Zavrtanik, D.
name: Zavrtanik, M.
name: Zepeda, A.
name: Zimmermann, B.
name: Ziolkowski, M.
name: Zong, Z.
name: Zuccarello, F.
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: Cosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come from studying the distribution of their arrival directions. Using $3 \times 10^4$ cosmic rays above $8 \times 10^{18}$ electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 square kilometers steradian year, we report an anisotropy in the arrival directions. The anisotropy, detected at more than the 5.2$σ$ level of significance, can be described by a dipole with an amplitude of $6.5_{-0.9}^{+1.3}$% towards right ascension $α_{d} = 100 \pm 10$ degrees and declination $δ_{d} = -24_{-13}^{+12}$ degrees. That direction indicates an extragalactic origin for these ultra-high energy particles.
description: 19 pages (with supplementary material), 8 figures