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 × 10^4 cosmic rays with energies above 8 × 10^18 electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 km2 sr year, we determined the existence of anisotropy in arrival directions. The anisotropy, detected at more than a 5.2s level of significance, can be described by a dipole with an amplitude of 6.5+1.3-0.9 percent toward right ascension a = 100 ± 10 degrees and declination dd = 24+12-13 degrees. That direction indicates an extra-galactic origin for these ultra-highenergy particles.

Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 × 1018 eV / A. Aab, P. Abreu, M. Aglietta, I..A..L. Samarai, I..F..M. Albuquerque, I. Allekotte, A. Almela, J..A. Castillo, J. Alvarez Muniz, G..A. Anastasi, L. Anchordoqui, B. Andrada, S. Andringa, C. Aramo, F. Arqueros, N. Arsene, H. Asorey, P. Assis, J. Aublin, G. Avila, A..M. Badescu, A. Balaceanu, F. Barbato, R..J..B. Luz, J..J. Beatty, K..H. Becker, J..A. Bellido, C. Berat, M..E. Bertaina, X. Bertou, P..L. Biermann, P. Billoir, J. Biteau, S..G. Blaess, A. Blanco, J. Blazek, C. Bleve, M. Bohã¡covã¡, D. Boncioli, C. Bonifazi, N. Borodai, A..M. Botti, J. Brack, I. Brancus, T. Bretz, A. Bridgeman, F..L. Briechle, P. Buchholz, A. Bueno, S. Buitink, M. Buscemi, K..S. Caballero mora, L. Caccianiga, A. Cancio, F. Canfora, L. Caramete, R. Caruso, A. Castellina, G. Cataldi, L. Cazon, A..G. Chavez, J..A. Chinellato, J. Chudoba, R..W. Clay, A. Cobos, R. Colalillo, A. Coleman, L. Collica, M..R. Coluccia, R. Conceição, G. Consolati, F. Contreras, M..J. Cooper, S. Coutu, C..E. Covault, J. Cronin, S. D'Amico, B. Daniel, S. Dasso, K. Daumiller, B..R. Dawson, R..M. De Almeida, S..J. De Jong, G. De Mauro, J..R..T. De Mello Neto, I. De Mitri, J. De Oliveira, V. De Souza, J. Debatin, O. Deligny, C. Di Giulio, A. Di Matteo, M..L..D. Castro, F. Diogo, C. Dobrigkeit, J..C. D'Olivo, Q. Dorosti, R..C. Dos Anjos, M..T. Dova, A. Dundovic, J. Ebr, R. Engel, M. Erdmann, M. Erfani, C..O. Escobar, J. Espadanal, A. Etchegoyen, H. Falcke, G. Farrar, A..C. Fauth, N. Fazzini, F. Fenu, B. Fick, J..M. Figueira, A. Filipcic, O. Fratu, M..M. Freire, T. Fujii, A. Fuster, R. Gaior, B. Garcã­a, D. Garcia pinto, F. Gaté, H. Gemmeke, A. Gherghel lascu, P..L. Ghia, U. Giaccari, M.G. Giammarchi, M. Giller, D. Glas, C. Glaser, G. Golup, M..G. Berisso, P..F..G. Vitale, G. N., A. Gorgi, P. Gorham, A..F. Grillo, T..D. Grubb, F. Guarino, G..P. Guedes, M..R. Hampel, P. Hansen, D. Harari, T..A. Harrison, J..L. Harton, A. Haungs, T. Hebbeker, D. Heck, P. Heimann, A..E. Herve, G..C. Hill, C. Hojvat, E. Holt, P. Homola, J..R. Hörandel, P. Horvath, M. Hrabovsky, T. Huege, J. Hulsman, A. Insolia, P..G. Isar, I. Jandt, S. Jansen, J..A. Johnsen, M. Josebachuili, J. Jurysek, A. Kaapa, O. Kambeitz, K..H. Kampert, I. Katkov, B. Keilhauer, N. Kemmerich, E. Kemp, J. Kemp, R..M. Kieckhafer, H..O. Klages, M. Kleifges, J. Kleinfeller, R. Krause, N. Krohm, D. Kuempel, G..K. Mezek, N. Kunka, A..K. Awad, D. Lahurd, M. Lauscher, R. Legumina, M..A..L. De Oliveira, A. Letessier selvon, I. Lhenry yvon, K. Link, D. Lo Presti, L. L., R. Lopez, A..L. Casado, Q. Luce, A. Lucero, M. Malacari, M. Mallamaci, D. Mandat, P. Mantsch, A..G. Mariazzi, I..C. Mariåÿ, G. Marsella, D. Martello, H. Martinez, O..M. Bravo, J..J..M. Meza, H..J. Mathes, S. Mathys, J. Matthews, J..A..J. Matthews, G. Matthiae, E. Mayotte, P..O. Mazur, C. Medina, G. Medina tanco, D. Melo, A. Menshikov, K..D. Merenda, S. Michal, M..I. Micheletti, L. Middendorf, L. Miramonti, B. Mitrica, D. Mockler, S. Mollerach, F. Montanet, C. Morello, M. Mostafá, A..L. Müller, G. Müller, M..A. Muller, S. Müller, R. Mussa, I. Naranjo, L. Nellen, P..H. Nguyen, M. Niculescu oglinzanu, M. Niechciol, L. Niemietz, T. Niggemann, D. Nitz, D. Nosek, V. Novotny, L. Noå¾ka, L..A. Nãºã±ez, L. Ochilo, F. Oikonomou, A. Olinto, M. Palatka, J. Pallotta, P. Papenbreer, G. Parente, P. A., T. Paul, M. Pech, F. Pedreira, J. Pkala, R. Pelayo, J. Peã±a rodriguez, L..A..S. Pereira, M. Perlã­n, L. Perrone, C. Peters, S. Petrera, J. Phuntsok, R. Piegaia, T. Pierog, P. Pieroni, M. Pimenta, V. Pirronello, M. Platino, M. Plum, C. Porowski, R..R. Prado, P. Privitera, M. Prouza, E..J. Quel, S. Querchfeld, S. Quinn, R. Ramos pollan, J. Rautenberg, D. Ravignani, B. Revenu, J. Ridky, F. Riehn, M. Risse, P. Ristori, V. Rizi, W..R. De Carvalho, G..R. Fernandez, J..R. Rojo, D. Rogozin, M..J. Roncoroni, M. Roth, E. Roulet, A..C. Rovero, P. Ruehl, S..J. Saffi, A. Saftoiu, F. Salamida, H. Salazar, A. Saleh, F..S. Greus, G. Salina, F. Sã¡nchez, P. Sanchez lucas, E..M. Santos, S. E., F. Sarazin, R. Sarmento, C..A. Sarmiento, R. Sato, M. Schauer, V. Scherini, H. Schieler, M. Schimp, D. Schmidt, O. Scholten, P. Schovãnek, F..G. Schröder, A. Schulz, J. Schumacher, S..J. Sciutto, A. Segreto, M. Settimo, A. Shadkam, R..C. Shellard, G. Sigl, G. Silli, O. Sima, A. Smialkowski, R. Å mã­da, G..R. Snow, P. Sommers, S. Sonntag, J. Sorokin, R. Squartini, D. Stanca, S. Stanic, J. Stasielak, P. Stassi, F. Strafella, F. Suarez, M..S. Durã¡n, T. Sudholz, T. Suomijã¤rvi, A..D. Supanitsky, J. Å upã­k, J. Swain, Z. Szadkowski, A. Taboada, O..A. Taborda, A. Tapia, V..M. Theodoro, C. Timmermans, C..J..T. Peixoto, L. Tomankova, B. Tomã©, G..T. Elipe, P. Travnicek, M. Trini, R. Ulrich, M. Unger, M. Urban, J..F..V. Galicia, I. Valiã±o, L. Valore, G. Van Aar, P. Van Bodegom, A..M. Van Den Berg, A. Van Vliet, E. Varela, B..V. Cã¡rdenas, G. Varner, R..A. Vã¡zquez, D. Veberic, V. C., I..D..V. Quispe, V. Verzi, J. Vicha, L. Villaseñor, S. Vorobiov, H. Wahlberg, O. Wainberg, D. Walz, A..A. Watson, M. Weber, A. Weindl, L. Wiencke, H. Wilczyński, M. Wirtz, D. Wittkowski, B. Wundheiler, L. Yang, A. Yushkov, E. Zas, D. Zavrtanik, M. Zavrtanik, A. Zepeda, B. Zimmermann, M. Ziolkowski, Z. Zong, F. Zuccarello. - In: SCIENCE. - ISSN 0036-8075. - 357:6357(2017 Sep 22), pp. 1266-1270. [10.1126/science.aan4338]

Observation of a large-scale anisotropy in the arrival directions of cosmic rays above 8 × 1018 eV

L. Caccianiga;L. Collica;M.G. Giammarchi;M. Mallamaci;L. Miramonti;
2017-09-22

Abstract

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 × 10^4 cosmic rays with energies above 8 × 10^18 electron volts, recorded with the Pierre Auger Observatory from a total exposure of 76,800 km2 sr year, we determined the existence of anisotropy in arrival directions. The anisotropy, detected at more than a 5.2s level of significance, can be described by a dipole with an amplitude of 6.5+1.3-0.9 percent toward right ascension a = 100 ± 10 degrees and declination dd = 24+12-13 degrees. That direction indicates an extra-galactic origin for these ultra-highenergy particles.
cosmic rays; uhecrs; auger; origin
Settore FIS/01 - Fisica Sperimentale
Settore FIS/04 - Fisica Nucleare e Subnucleare
Settore FIS/05 - Astronomia e Astrofisica
Article (author)
File in questo prodotto:
File Dimensione Formato  
1266.full.pdf

accesso riservato

Tipologia: Publisher's version/PDF
Dimensione 1.2 MB
Formato Adobe PDF
1.2 MB Adobe PDF   Visualizza/Apri   Richiedi una copia
Pubblicazioni consigliate

Caricamento pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/527164
Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 213
  • ???jsp.display-item.citation.isi??? 179
social impact