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Preliminary analysis of two-hemisphere observations of sidereal anisotropies of galactic cosmic rays


Hall, DL and Munakata, K and Yasue, S and Mori, S and Kato, C and Koyama, M and Akahane, S and Fujii, Z and Fujimoto, K and Humble, JE and Fenton, AG and Fenton, KB and Duldig, ML, Preliminary analysis of two-hemisphere observations of sidereal anisotropies of galactic cosmic rays, Journal of Geophysical Research: Space Physics, 103, (A1) pp. 367-372. ISSN 0148-0227 (1998) [Refereed Article]

DOI: doi:10.1029/97JA02520


By using the two-hemisphere network of underground muon telescopes we have examined the average sidereal daily variations in the count rates recorded by 48-component muon telescopes. The telescopes respond to primary cosmic rays with rigidities between ∼140 and 1700 GV and view almost the entire celestial sphere. We have modeled the data by using Gaussian functions, and we have related the Gaussian parameters to the recent tail-in and loss cone anisotropy model proposed by Nagashima et al. [1995a, b] to explain the sidereal daily variations. We have used the model parameters to derive the rigidity and latitude spectra of the galactic anisotropies and find them to be qualitatively in agreement with Nagashima et al.'s predictions. The results indicate, however, that the tail-in anisotropy is asymmetric about its reference axis, whereas the loss cone anisotropy is more symmetric. We show that these characteristics of the galactic anisotropies may explain the north-south asymmetry observed in the amplitude of the sidereal diurnal variation derived from Fourier analysis techniques. Copyright 1998 by the American Geophysical Union.

Item Details

Item Type:Refereed Article
Research Division:Physical Sciences
Research Group:Astronomical sciences
Research Field:High energy astrophysics and galactic cosmic rays
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the physical sciences
UTAS Author:Humble, JE (Dr John Humble)
UTAS Author:Fenton, AG (Dr Geoff Fenton)
UTAS Author:Fenton, KB (Dr Peter Fenton)
UTAS Author:Duldig, ML (Dr Marc Duldig)
ID Code:13372
Year Published:1998
Web of Science® Times Cited:14
Deposited By:Physics
Deposited On:1998-08-01
Last Modified:2011-08-08

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