We present a detailed study of the large-scale anisotropies of cosmic rays with energies above 4 EeV measured using the Pierre Auger Observatory. For the energy bins [4, 8] EeV and E ≥ 8 EeV, the most significant signal is a dipolar modulation in R.A. at energies above 8 EeV, as previously reported. In this paper we further scrutinize the highest-energy bin by splitting it into three energy ranges. We find that the amplitude of the dipole increases with energy above 4 EeV. The growth can be fitted with a power law with index β = 0.79 ± 0.19. The directions of the dipoles are consistent with an extragalactic origin of these anisotropies at all the energies considered. Additionally, we have estimated the quadrupolar components of the anisotropy: they are not statistically significant. We discuss the results in the context of the predictions from different models for the distribution of ultrahigh-energy sources and cosmic magnetic fields.

Large-scale Cosmic-Ray Anisotropies above 4 EeV Measured by the Pierre Auger Observatory / A. Aab, P. Abreu, M. Aglietta, I.F.M. Albuquerque, J.M. Albury, I. Allekotte, A. Almela, J.A. Castillo, J. Alvarez-Muñiz, G.A. Anastasi, L. Anchordoqui, B. Andrada, S. Andringa, C. Aramo, H. Asorey, P. Assis, G. Avila, A.M. Badescu, A. Balaceanu, F. Barbato, R.J.B. Luz, S. Baur, K.H. Becker, J.A. Bellido, C. Berat, M.E. Bertaina, X. Bertou, P.L. Biermann, J. Biteau, S.G. Blaess, A. Blanco, J. Blazek, C. Bleve, M. Boháčová, C. Bonifazi, N. Borodai, A.M. Botti, J. Brack, T. Bretz, A. Bridgeman, F.L. Briechle, P. Buchholz, A. Bueno, S. Buitink, M. Buscemi, K.S. Caballero-Mora, L. Caccianiga, L. Calcagni, A. Cancio, F. Canfora, J.M. Carceller, R. Caruso, A. Castellina, F. Catalani, G. Cataldi, L. Cazon, J.A. Chinellato, J. Chudoba, L. Chytka, R.W. Clay, A.C.C. Cerutti, R. Colalillo, A. Coleman, M.R. Coluccia, R. Conceição, G. Consolati, F. Contreras, M.J. Cooper, S. Coutu, C.E. Covault, B. Daniel, S. Dasso, K. Daumiller, B.R. Dawson, J.A. Day, R.M.D. Almeida, S.J.D. Jong, G. De Mauro, J.R.T.D.M. Neto, I. De Mitri, J. Deoliveira, V. De Souza, J. Debatin, O. Deligny, N. Dhital, M.L. Díaz Castro, F. Diogo, C. Dobrigkeit, J.C. D'Olivo, Q. Dorosti, R.C.D. Anjos, M.T. Dova, A. Dundovic, J. Ebr, R. Engel, M. Erdmann, C.O. Escobar, A. Etchegoyen, H. Falcke, J. Farmer, G. Farrar, A.C. Fauth, N. Fazzini, F. Feldbusch, F. Fenu, L.P. Ferreyro, J.M. Figueira, A. Filipčič, M.M. Freire, T. Fujii, A. Fuster, B. García, H. Gemmeke, A. Gherghel-Lascu, P.L. Ghia, U. Giaccari, M. Giammarchi, M. Giller, D. Głas, J. Glombitza, G. Golup, M.G. Berisso, P.F.G. Vitale, N. González, I. Goos, D. Góra, A. Gorgi, M. Gottowik, T.D. Grubb, F. Guarino, G.P. Guedes, E. Guido, R. Halliday, M.R. Hampel, P. Hansen, D. Harari, T.A. Harrison, V.M. Harvey, A. Haungs, T. Hebbeker, D. Heck, P. Heimann, G.C. Hill, C. Hojvat, E.M. Holt, P. Homola, J.R. Hörandel, P. Horvath, M. Hrabovský, T. Huege, J. Hulsman, A. Insolia, P.G. Isar, I. Jandt, J.A. Johnsen, M. Josebachuili, J. Jurysek, A. Käpä, K.H. Kampert, B. Keilhauer, N. Kemmerich, J. Kemp, H.O. Klages, M. Kleifges, J. Kleinfeller, R. Krause, D. Kuempel, G.K. Mezek, A.K. Awad, B.L. Lago, D. Lahurd, R.G. Lang, R. Legumina, M.A.L. De Oliveira, V. Lenok, A. Letessier-Selvon, I. Lhenry-Yvon, D. Lo Presti, L. Lopes, R. López, A.L. Casado, R. Lorek, Q. Luce, A. Lucero, M. Malacari, M. Mallamaci, G. Mancarella, D. Mandat, P. Mantsch, A.G. Mariazzi, I.C. Mariş, G. Marsella, D. Martello, H. Martinez, O. Martínez Bravo, H.J. Mathes, S. Mathys, J. Matthews, G. Matthiae, E. Mayotte, P.O. Mazur, G. Medina-Tanco, D. Melo, A. Menshikov, K.-. Merenda, S. Michal, M.I. Micheletti, L. Middendorf, L. Miramonti, B. Mitrica, D. Mockler, S. Mollerach, F. Montanet, C. Morello, G. Morlino, M. Mostafá, A.L. Müller, M.A. Muller, S. Müller, R. Mussa, L. Nellen, P.H. Nguyen, M. Niculescu-Oglinzanu, M. Niechciol, D. Nitz, D. Nosek, V. Novotny, L. Nožka, A. Nucita, L.A. Nñez, A. Olinto, M. Palatka, J. Pallotta, P. Papenbreer, G. Parente, A. Parra, M. Pech, F. Pedreira, J. Pkala, R. Pelayo, J. Peña-Rodriguez, L.A.S. Pereira, M. Perlin, L. Perrone, C. Peters, S. Petrera, J. Phuntsok, T. Pierog, M. Pimenta, V. Pirronello, M. Platino, J. Poh, B. Pont, C. Porowski, R.R. Prado, P. Privitera, M. Prouza, A. Puyleart, S. Querchfeld, S. Quinn, R. Ramos-Pollan, J. Rautenberg, D. Ravignani, M. Reininghaus, J. Ridky, F. Riehn, M. Risse, P. Ristori, V. Rizi, W.R. De Carvalho, J.R. Rojo, M.J. Roncoroni, M. Roth, E. Roulet, A.C. Rovero, P. Ruehl, S.J. Saffi, A. Saftoiu, F. Salamida, H. Salazar, A. Saleh, G. Salina, F. Sánchez, E.M. Santos, E. Santos, F. Sarazin, R. Sarmento, C. Sarmiento-Cano, R. Sato, P. Savina, M. Schauer, V. Scherini, H. Schieler, M. Schimassek, M. Schimp, D. Schmidt, O. Scholten, P. Schovánek, F.G. Schröder, S. Schröder, J. Schumacher, S.J. Sciutto, R.C. Shellard, G. Sigl, G. Silli, O. Sima, R. Šmída, G.R. Snow, P. Sommers, J.F. Soriano, J. Souchard, R. Squartini, D. Stanca, S. Stanič, J. Stasielak, P. Stassi, M. Stolpovskiy, A. Streich, F. Suarez, M. Suárez-Durán, T. Sudholz, T. Suomijärvi, A.D. Supanitsky, J. Šupík, Z. Szadkowski, A. Taboada, O.A. Taborda, A. Tapia, C. Timmermans, C.J.T. Peixoto, B. Tomé, G.T. Elipe, P. Travnicek, M. Trini, M. Tueros, R. Ulrich, M. Unger, M. Urban, J.F.V. Galicia, I. Valiño, L. Valore, P.V. Bodegom, A.M.V.D. Berg, A.V. Vliet, E. Varela, B.V. Cárdenas, R.A. Vázquez, D. Veberič, C. Ventura, I.D.V. Quispe, V. Verzi, J. Vicha, L. Villaseñor, S. Vorobiov, H. Wahlberg, O. Wainberg, A.A. Watson, M. Weber, A. Weindl, M. Wiedeński, L. Wiencke, H. Wilczyński, M. Wirtz, D. Wittkowski, B. Wundheiler, L. Yang, A. Yushkov, E. Zas, D. Zavrtanik, M. Zavrtanik, L. Zehrer, A. Zepeda, B. Zimmermann, M. Ziolkowski, Z. Zong, F. Zuccarello. - In: THE ASTROPHYSICAL JOURNAL. - ISSN 0004-637X. - 868:1(2018 Nov 20). [10.3847/1538-4357/aae689]

Large-scale Cosmic-Ray Anisotropies above 4 EeV Measured by the Pierre Auger Observatory

L. Caccianiga;M. Giammarchi;L. Miramonti;
2018

Abstract

We present a detailed study of the large-scale anisotropies of cosmic rays with energies above 4 EeV measured using the Pierre Auger Observatory. For the energy bins [4, 8] EeV and E ≥ 8 EeV, the most significant signal is a dipolar modulation in R.A. at energies above 8 EeV, as previously reported. In this paper we further scrutinize the highest-energy bin by splitting it into three energy ranges. We find that the amplitude of the dipole increases with energy above 4 EeV. The growth can be fitted with a power law with index β = 0.79 ± 0.19. The directions of the dipoles are consistent with an extragalactic origin of these anisotropies at all the energies considered. Additionally, we have estimated the quadrupolar components of the anisotropy: they are not statistically significant. We discuss the results in the context of the predictions from different models for the distribution of ultrahigh-energy sources and cosmic magnetic fields.
astroparticle physics; cosmic rays; Astronomy and Astrophysics; Space and Planetary Science
Settore FIS/01 - Fisica Sperimentale
Settore FIS/04 - Fisica Nucleare e Subnucleare
Settore FIS/05 - Astronomia e Astrofisica
20-nov-2018
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/605925
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