Large-Scale Cosmic-Ray Anisotropy with KASCADE
TL;DR: In this article, the results of an analysis of the large-scale anisotropy of cosmic rays in the PeV range were presented, and the Rayleigh formalism was applied to the right ascension distribution of extensive air showers measured by the KASCADE (Karlsruhe Shower Core and Array Detector) experiment.
Abstract: We present the results of an analysis of the large-scale anisotropy of cosmic rays in the PeV range. The Rayleigh formalism is applied to the right ascension distribution of extensive air showers measured by the KASCADE (Karlsruhe Shower Core and Array Detector) experiment. The data set contains about 108 extensive air showers in the energy range 0.7-6 PeV. No hints of anisotropy are visible in the right ascension distributions in this energy range. This accounts for all showers, as well as for subsets containing showers induced by predominantly light or heavy primary particles, respectively. Upper flux limits for Rayleigh amplitudes are determined to be between 10-3 at a primary energy of 0.7 PeV and 10-2 at 6 PeV.
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01 Apr 2002
TL;DR: In this article, direct and indirect measurements of cosmic rays are reviewed, with emphasis given to the understanding of the knee in the energy spectrum, and the data are compared to contemporary models for the knee.
Abstract: Results from direct and indirect measurements of cosmic rays are reviewed. Emphasis is given to the understanding of the knee in the energy spectrum. The data are compared to contemporary models for the knee. Implications on the present understanding of the origin of galactic cosmic rays are discussed.
319 citations
TL;DR: In this paper, a review summarizes recent developments in the understanding of high-energy cosmic rays focusing on galactic and presumably extragalactic particles in the energy range from the knee (1015 eV ) up to the highest energies observed ( > 10 20 eV).
Abstract: This review summarizes recent developments in the understanding of high-energy cosmic rays. It focuses on galactic and presumably extragalactic particles in the energy range from the knee (1015 eV ) up to the highest energies observed ( > 10 20 eV). Emphasis is put on observational results, their interpretation, and the global picture of cosmic rays that has emerged during the last decade.
300 citations
Hirosaki University1, Saitama University2, Chinese Academy of Sciences3, Yokohama National University4, Hebei Normal University5, Tibet University6, Shandong University7, Southwest Jiaotong University8, Yunnan University9, Kanagawa University10, Utsunomiya University11, University of Tokyo12, Konan University13, Shibaura Institute of Technology14, Shinshu University15, Tsinghua University16, Waseda University17, National Institute of Informatics18, College of Industrial Technology19, Shonan Institute of Technology20
TL;DR: Two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV) is presented, using the large data sample of the Tibet Air Shower Arrays, revealing finer details of the known anisotropies.
Abstract: The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of Galactic cosmic ray anisotropy in sidereal time is uncovered around the Cygnus region direction. For cosmic-ray energies up to a few hundred TeV, all components of anisotropies fade away, showing a corotation of Galactic cosmic rays with the local Galactic magnetic environment. These results have broad implications for a comprehensive understanding of cosmic rays, supernovae, magnetic fields, and heliospheric and Galactic dynamic environments.
259 citations
TL;DR: In this article, the effects of stochasticity in the spatial and temporal distribution of supernova remnants on the anisotropy of cosmic rays observed at Earth were investigated for different choices of the diffusion coefficient D(E) experienced by cosmic rays during propagation in the Galaxy.
Abstract: In this paper we investigate the effects of stochasticity in the spatial and temporal distribution of supernova remnants on the anisotropy of cosmic rays observed at Earth. The calculations are carried out for different choices of the diffusion coefficient D(E) experienced by cosmic rays during propagation in the Galaxy. The propagation and spallation of nuclei (with charge 1 ≤ Z ≤ 26) are taken into account. At high energies (E > 1 TeV) we assume that D(E)∝(E/Z)δ, with δ = 1/3 and δ = 0.6 being the reference scenarios. The large scale distribution of supernova remnants in the Galaxy is modeled following the distribution of pulsars with and without accounting for the spiral structure of the Galaxy. Our calculations allow us to determine the contribution to anisotropy resulting from both the large scale distribution of SNRs in the Galaxy and the random distribution of the nearest remnants. The naive expectation that the anisotropy amplitude scales as δA∝D(E) is shown to be a wild oversimplification of reality which does not reflect in the predicted anisotropy for any realistic distribution of the sources. The fluctuations in the anisotropy pattern are dominated by nearby sources, so that predicting or explaining the observed anisotropy amplitude and phase becomes close to impossible. Nevertheless, the results of our calculations, when compared to the data, allow us to draw interesting conclusions in terms of the propagation scenario to be preferred both in terms of the energy dependence of the diffusion coefficient and of the size of the halo. We find that the very weak energy dependence of the anisotropy amplitude below 105 GeV, as observed by numerous experiments, as well as the rise at higher energies, can best be explained if the diffusion coefficient is D(E)∝E1/3. Faster diffusion, for instance with δ = 0.6, leads in general to an exceedingly large anisotropy amplitude. The spiral structure introduces interesting trends in the energy dependence of the anisotropy pattern, which qualitatively reflect the trend seen in the data. The inhomogeneous spatial distribution of the sources in the Galactic disc induces a large scale anisotropy which is not sensitive to the stochastic nature of nearby SNRs: we find that this additional contribution to δA becomes more important for large values of the size of the halo, H. The two terms are comparable in size for H ~ 2 kpc which corresponds to the scale height of the gradient of the spatial distribution of SNRs in the Galaxy. The dependence on energy of δA(E) is close to monotonic when the large-scale, regular term dominates, and does not seem to reflect the observed anisotropy amplitude. Both contributions to the total anisotropy are illustrated and discussed with the help of semi-analytical results.
149 citations
TL;DR: In this article, the authors review the many possibilities which have been explored in the literature to address this question, including origins at either Galactic or extragalactic celestial objects, and briefly discuss new physical processes which may either explain or be constrained by IceCube data.
Abstract: The announcement by the IceCube Collaboration of the observation of 28 cosmic neutrino candidates has been greeted with a great deal of justified excitement. The data reported so far depart by 4.3 σ from the expected atmospheric neutrino background, which raises the obvious question: “Where in the Cosmos are these neutrinos coming from?” We review the many possibilities which have been explored in the literature to address this question, including origins at either Galactic or extragalactic celestial objects. For completeness, we also briefly discuss new physical processes which may either explain or be constrained by IceCube data.
144 citations
References
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30 Apr 1998TL;DR: In this paper, the evolution of the information seeking and use models for professionals, essentially, the information access practices, is discussed. But two main categories can be distinguished : the informationseeking and use model versus the information retrieval model, and we will evaluate them in order to see if a convergence is possible with the same vocabulary and procedures.
Abstract: This study concerns the evolution of the information seeking and use models for professionals essentially, the information access practices. Coming from Anglo-Saxon literature, this new information science research trend, evolve with paradigms and different information seeking and use models have emerged, in order to explain how professional seeks information and what can be done in order to help them. Two main categories can be distinguished : the information seeking and use model versus the information retrieval model. So we will present today this diversity of models and we will evaluate them in order to see if a convergence is possible with the same vocabulary and procedures.
1,294 citations
"Large-Scale Cosmic-Ray Anisotropy w..." refers methods in this paper
...The EASs are simulated utilizing the CORSIKA package ( Heck et al. 1998 )....
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...The extensive air showers are simulated utilising the CORSIKA package (Heck et al. 1998)....
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01 Feb 1997
TL;DR: The reliability of model calculations is of considerable significance because at energies above those attained by accelerators only model predictions enable us to extract primary cosmic ray characteristics as discussed by the authors, which is of particular relevance in the case of EAS simulations.
Abstract: The reliability of model calculations is of considerable significance because at energies above those attained by accelerators only model predictions enable us to extract primary cosmic ray characteristics. Different phenomenological models based on the quark-gluon picture of hadron interactions are of use now as a foundation for experimental data analysis at energies > 10 15 eV. In this paper we consider the present status of quark-gluon string (QGS) model with allowance made for semihard processes and (in the framework of so advanced model) discuss experimental data obtained at energies 10 15 ÷ 10 19 eV. In doing so we assume mass composition following from the diffusion notions of cosmic ray propagation through the Galaxy. Some general problems of EAS simulation and among them the simulation of electron-photon cascades are also discussed.
515 citations
11 Nov 2003-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The KASCADE experiment as mentioned in this paper was designed to measure air showers of primary cosmic-ray energies in the PeV region and to investigate the knee phenomenon in the all-particle energy spectrum.
Abstract: KASCADE has been designed to measure air showers of primary cosmic-ray energies in the PeV region and to investigate the knee phenomenon in the all-particle energy spectrum. Several observations are measured simultaneously for each event by different detector systems. The experiment started to take data in 1996 and has been completed and extended since then. The individual detector systems and their performances are described. Also, the experience in long-term operation of the experiment and the interplay between different components is outlined.
333 citations
"Large-Scale Cosmic-Ray Anisotropy w..." refers background in this paper
...KASCADE measures the electromagnetic, muonic, and hadronic components of air showers with three major detector systems: a large field array, a muon tracking detector, and a central detector (T. Antoni et al. 2003a)....
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...…electron number Ne and the truncated muon number Nµ,tr are zenith angle corrected to Θ = 0◦ using the attenuation law: N0e = Ne · exp (X0/Λe(secΘ− 1)) (5) N0µ,tr = Nµ,tr · exp (X0/Λµ,tr(secΘ− 1)) (6) with the attenuation lengths ΛNe = 175 g/cm 2 and ΛNµ,tr = 823 g/cm 2 (Antoni et al. 2003b)....
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01 Jan 1985
149 citations
"Large-Scale Cosmic-Ray Anisotropy w..." refers methods in this paper
...The transformation matrix is determined from CORSIKA simulations using the hadronic interaction models QGSJET and GHEISHA....
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...The QGSJet-model (Kalmykov, Ostapchenko, & Pavlov 1997) is used for hadronic interactions above ELab > 80 GeV, GHEISHA (Fesefeldt 1985) for interactions below this energy....
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