Large-Scale Sidereal Anisotropy of Galactic Cosmic-Ray Intensity Observed by the Tibet Air Shower Array

Amenomori, M.; Ayabe, S.; Cui, S. W.; Danzengluobu,; Ding, L. K.; Ding, X. H.; Feng, C.; Feng, Z.; Gao, X. Y.; Geng, Q. X.; Guo, H. W.; He, H. H.; He, M.; Hibino, K.; Hotta, N.; Hu, Haibing; Huang, J.; Huang, Q.; Jia, H. Y.; Kajino, F.; Kasahara, K.; Katayose, Y.; Kato, C.; Kawata, K.; Labaciren,; Le, G. M.; Li, J. Y.; Lü, H.; Lu, S. L.; Meng, X. R.; Mizutani, K.; Mu, J.; Munakata, K.; Nagai, A.; Nanjo, H.; Nakamura, Masaki; Ohnishi, M.; Ohta, I.; Onuma, H.; Ouchi, T.; Ozawa, S.; Ren, J. R.; Saito, T.; Sakata, M.; Sasaki, Takashi; Shibata, M.; Shirai, T.; Sugimoto, H.; Takita, M.; Tan, Y. H.; Tateyama, N.; Torii, Shoji; Tsuchiya, H.; Udo, S.; Utsugi, Toshihiro; Wang, B. S.; Wang, H.; Wang, X.; Wang, Y. G.; Wu, H. R.; Xue, L.; Yamamoto, Y.; Yan, C. T.; Yang, X. C.; Yasue, S.; Ye, Z. H.; Yu, G. C.; Yuan, A. F.; Yuda, T.; Zhang, H. M.; Zhang, J. L.; Zhang, N. J.; Zhang, X. Y.; Zhang, Y.; Zhang, Yi; Zhaxisangzhu,; Zhou, Xu

doi:10.1086/431582

Cited by 117 publications

(78 citation statements)

References 21 publications

(34 reference statements)

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“…the lower energies, where cosmic rays follows adiabatically the magnetic field lines, and the higher energies, where the heliospheric influence starts to become subdominant. This is in general agreement with the energy dependence of the anisotropy amplitude that increases up to about 10 TeV and decreases above this energy (Amenomori et al, 2005). Resonant scattering may be able to redistribute the 10 −3 interstellar anisotropic component of the cosmic ray arrival distribution, depending on particle energy and pitch angle, and on the properties of heliospheric magnetic field inside the tail and on the heliopause.…”

Section: Heliospheric Influence On Tev Cosmic Rayssupporting

confidence: 85%

“…These results show that the anisotropy matches the observations in the Northern Hemisphere and that a sudden change in its topology occurs at energy in excess of a few hundreds of TeV, confirming the observations by Aglietta et al (2009). The transition between the two anisotropy regimes is preceded by a steady decrease of the amplitude at particle energy above 10 TeV, following an increase trend at lower energies (see Amenomori et al, 2005 for instance). The global anisotropy cannot be described with a simple dipole, but as a superposition of spherical harmonic contributions, where statistically significant small angular scale features, with amplitude of order 10 −5 -10 −4 , are also observed (Abbasi et al, 2011;Santander et al, 2013a), in agreement with similar observations in the Northern Hemisphere (Amenomori et al, 2007;Abdo et al, 2008;Bartoli et al, 2013;BenZvi et al, 2013), as shown in Fig.…”

Section: Introductionsupporting

confidence: 86%

“…Observations in the Northern Hemisphere were reported from energies of tens to several hundreds of GeV with muon detectors (Nagashima et al, 1998;Hall et al, 1999;Munakata et al, 2010), in the one to tens of TeV energy range with various surface arrays and underground detectors (Amenomori et al, 2005(Amenomori et al, , 2006(Amenomori et al, , 2011Guillian et al, 2007;Abdo et al, 2009;Amenomori et al, 2009;Cui, 2011;Di Sciascio, 2013;de Jong, 2011;BenZvi et al, 2013;Santander et al, 2013a), up to hundreds of TeV (Aglietta et al, 2009). Recently, similar observations of a large angular scale anisotropy were reported in the Southern Hemisphere by the IceCube Observatory, in the energy range between 10 TeV and a few PeV (Abbasi et al, 2010(Abbasi et al, , 2012Aartsen et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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TeV Cosmic Ray Anisotropy and the Heliospheric Magnetic Field

Desiati

Lazarían

2014

ASTRA Proc.

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Abstract. Cosmic rays are observed to possess a small non uniform distribution in arrival direction. Such anisotropy appears to have a roughly consistent topology between tens of GeV and hundreds of TeV, with a smooth energy dependency on phase and amplitude. Above a few hundreds of TeV a sudden change in the topology of the anisotropy is observed. The distribution of cosmic ray sources in the Milky Way is expected to inject anisotropy on the cosmic ray flux. The nearest and most recent sources, in particular, are expected to contribute more significantly than others. Moreover the interstellar medium is expected to have different characteristics throughout the Galaxy, with different turbulent properties and injection scales. Propagation effects in the interstellar magnetic field can shape the cosmic ray particle distribution as well. In particular, in the 1-10 TeV energy range, they have a gyroradius comparable to the size of the Heliosphere, assuming a typical interstellar magnetic field strength of 3 µG. Therefore they are expected to be strongly affected by the Heliosphere in a manner ordered by the direction of the local interstellar magnetic field and of the heliotail. In this paper we discuss on the possibility that TeV cosmic rays arrival distribution might be significantly redistributed as they propagate through the Heliosphere.

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Section: Heliospheric Influence On Tev Cosmic Rayssupporting

confidence: 85%

Section: Introductionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

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TeV Cosmic Ray Anisotropy and the Heliospheric Magnetic Field

Desiati

Lazarían

2014

ASTRA Proc.

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“…From an observational point of view, a statistically significant anisotropy has been observed by a variety of experiments, sensitive to different energy ranges (from tens of GeV to a few PeV), located on or below the Earth's surface in the Northern Hemisphere (Nagashima et al 1998;Hall et al 1999;Amenomori et al 2005Amenomori et al , 2006Amenomori et al , 2011Guillian et al 2007;Abdo et al 2009;Aglietta et al 2009;Zhang et al 2009;Munakata et al 2010;Cui et al 2011;de Jong et al 2011;Bartoli et al 2015) and in the Southern Hemisphere (Abbasi et al 2010(Abbasi et al , 2011(Abbasi et al , 2012Aartsen et al 2013Aartsen et al , 2016.…”

Section: The Problem Of Anisotropies and Corresponding Approachesmentioning

confidence: 99%

TeV Cosmic-Ray Anisotropy from the Magnetic Field at the Heliospheric Boundary

López-Barquero

Desiati

Lazarían

et al. 2017

ApJ

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We performed numerical calculations to test the suggestion by Desiati and Lazarian that the anisotropies of TeV cosmic rays may arise from their interactions with the heliosphere. For this purpose, we used a magnetic field model of the heliosphere and performed direct numerical calculations of particle trajectories. Unlike earlier papers testing the idea, we did not employ time-reversible techniques that are based on Liouville's theorem. We showed numerically that for scattering by the heliosphere, the conditions of Liouville's theorem are not satisfied, and the adiabatic approximation and time-reversibility of the particle trajectories are not valid. Our results indicate sensitivity to the magnetic structure of the heliospheric magnetic field, and we expect that this will be useful for probing this structure in future research.

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“…Recently, due to greatly improved observational methods, the direct observation of S i A has become possible in the high-energy region by observations with cosmic ray and gamma-ray detectors (e.g. Amenomori et al, 2004Amenomori et al, , 2005Guillian et al, 2007;Abdo et al, 2008;Abbasi et al, 2010). This method is, however, not applicable to S i A in the lower energy region as cosmic rays cannot maintain their direction hindered by the influence of the heliomagnetic and geomagnetic fields.…”

Section: Introductionmentioning

confidence: 99%

The existence of cosmic ray sidereal anisotropies of galactic and solar origins with energies lower than 104 GeV and their modulation caused by the presumed behavior pattern of the heliomagnetosphere and of its neighboring gaseous matter in interstellar magnetic field

et al. 2012

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It is shown that the sidereal anisotropy (S i A) of cosmic rays (CRs) with energies smaller than 10 4 GeV consists of three kinds: one (GA) is of galactic origin from the direction G (α G = 0 hr; δ G = −20• ), and the other two (tail-in TA and nose-in HA) are of solar origin from the respective directions T (α T = 6 hr; δ T ∼ −24• ) and H (α H = 18 hr; δ H > 0• ) and supposed to be produced by the acceleration of CRs on the tail and nose boundaries of the heliomagnetosphere (HMS). This conclusion was arrived at in 1995 after a long-term delay since the beginning of CR observations in the early 20-th century. This delay was mainly due to the inconsistency among observations caused by the belief that the sidereal anisotropy must be unidirectional in space. The inconsistency has been solved at least qualitatively by the discovery of GA and TA. These anisotropies, including also HA, are subject, respectively, to their proper solar modulations in the HMS characterized by a polarity reversal every 11 years of the solar polar magnetic field and solar activity dependence with an 11-year periodicity. By using these modulation patterns, the origins of the three anisotropies have been determined. TA and HA thus determined inversely produce the following kinds of evidence and problems in the HMS: (1) the structure of the HMS, (2) acceleration of CRs on the boundary of the HMS, (3) CR Lens Effect of the HMS for the sharp concentration of TA and HA, (4) the proper motion (V HMS ) of the HMS relative to neighboring stars, (5) the proper motion of interstellar gaseous matter (including the magnetic field) relative to neighboring stars, and (6) the existence of the Subordinate HMS surrounding the HMS for the explanation of the duality of the motion of the HMS and also of the absence of the Compton-Getting (C-G) effect on the HMS. The present paper not only presents a brief summary of the studies of CR sidereal anisotropy made by many researchers during the 20th century leading to the present understanding, but also presents some problems to open up a new vista of the future.

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Large-Scale Sidereal Anisotropy of Galactic Cosmic-Ray Intensity Observed by the Tibet Air Shower Array

Cited by 117 publications

References 21 publications

TeV Cosmic Ray Anisotropy and the Heliospheric Magnetic Field

TeV Cosmic Ray Anisotropy and the Heliospheric Magnetic Field

TeV Cosmic-Ray Anisotropy from the Magnetic Field at the Heliospheric Boundary

The existence of cosmic ray sidereal anisotropies of galactic and solar origins with energies lower than 104 GeV and their modulation caused by the presumed behavior pattern of the heliomagnetosphere and of its neighboring gaseous matter in interstellar magnetic field

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