Abstract

This paper reports on the measurement of the large-scale anisotropy in the distribution of cosmic-ray arrival directions using the data collected by the air shower detector ARGO-YBJ from 2008 January to 2009 December, during the minimum of solar activity between cycles 23 and 24. In this period, more than 2 × 1011 showers were recorded with energies between ∼1 and 30 TeV. The observed two-dimensional distribution of cosmic rays is characterized by two wide regions of excess and deficit, respectively, both of relative intensity ∼10−3 with respect to a uniform flux, superimposed on smaller size structures. The harmonic analysis shows that the large-scale cosmic-ray relative intensity as a function of R.A. can be described by the first and second terms of a Fouries series. The high event statistics allow the study of the energy dependence of the anistropy, showing that the amplitude increases with energy, with a maximum intensity at ∼10 TeV, and then decreases while the phase slowly shifts toward lower values of R.A. with increasing energy. The ARGO-YBJ data provide accurate observations over more than a decade of energy around this feature of the anisotropy spectrum.

Autore Pugliese

• Marsella Giovanni , Bernardini Paolo , Perrone Lorenzo , Mancarella Giovanni

Tutti gli autori

• Bartoli B. , Bernardini P. , Bi X. J. , Cao Z. , Catalanotti S. , Chen S. Z. , Chen T. L. , Cui S. W. , Dai B. Z. , D'Amone A. , Danzengluobu , De Mitri I. , D'Ettorre Piazzoli B. , Di Girolamo T. , Di Sciascio G. , Feng C. F. , Feng Z. , Feng Z. , Gao W. , Gou Q. B. , Guo Y. Q. , He H. H. , Haibing H.U. , Hongbo H.U. , Iacovacci M. , Iuppa R. , Jia H. Y. , Labaciren , Li H. J. , Liu C. , Liu, J. , Liu M. Y. , Lu H. , Ma L. L. , Ma X. H. , Mancarella G. , Mari S. M. , Marsella G. , Mastroianni S. , Montini P. , Ning C. C. , Perrone L. , Pistilli P. , Salvini P. , Santonico R. , Shen P. R. , Sheng X. D. , Shi F. , Surdo A. , Tan Y. H. , Vallania P. , Vernetto S. , Vigorito C. , Wang H. , Wu C. Y. , Wu H. R. , Xue L. , Yang Q. Y. , Yang X. C. , Yao Z. G. , Yuan A. F. , Zha M. , Zhang H. M. , Zhang L. , Zhang X. Y. , Zhang Y. , Zhao J. , Zhaxiciren , Zhaxisangzhu , Zhou X. X. , Zhu F. R. , Zhu Q. Q.

Titolo volume/Rivista

THE ASTROPHYSICAL JOURNAL

Anno di pubblicazione

2015

ISSN

0004-637X

ISBN

Non Disponibile

Numero di citazioni Wos

Nessuna citazione

Ultimo Aggiornamento Citazioni

Non Disponibile

Numero di citazioni Scopus

16

Ultimo Aggiornamento Citazioni

28/04/2018

Settori ERC

Non Disponibile

Codici ASJC

Non Disponibile