Author
H. Y. Jia
Other affiliations: Shandong University
Bio: H. Y. Jia is an academic researcher from Southwest Jiaotong University. The author has contributed to research in topics: Air shower & Cosmic ray. The author has an hindex of 16, co-authored 28 publications receiving 1198 citations. Previous affiliations of H. Y. Jia include Shandong University.
Papers
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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
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Hirosaki University1, Chinese Academy of Sciences2, Yokohama National University3, Hebei Normal University4, Tibet University5, Shandong University6, Southwest Jiaotong University7, Yunnan University8, Kanagawa University9, Utsunomiya University10, University of Tokyo11, Konan University12, Waseda University13, Shinshu University14, Tsinghua University15, Saitama University16, National Institute of Informatics17, College of Industrial Technology18, Max Planck Society19, Shonan Institute of Technology20
TL;DR: In this paper, the authors presented an updated all-particle energy spectrum of primary cosmic rays in a wide range from 10 14 to 10 17 eVusing 5:5 ; 10 7 events collected from 2000 November through 2004 October by the Tibet-III air-shower array located 4300 m in altitude.
Abstract: We present an updated all-particle energy spectrum of primary cosmic rays in a wide range from 10 14 to 10 17 eVusing 5:5 ; 10 7 events collected from 2000 November through 2004 October by the Tibet-III air-shower array located 4300 m abovesealevel(anatmosphericdepthof 606gcm � 2 ).Thesizespectrumexhibitsasharpkneeatacorrespondingprimary energy around 4 PeV. This work uses increased statistics and new simulation calculations for the analysis. We discuss our extensive Monte Carlo calculations and the model dependencies involved in thefinal result, assuming interaction models QGSJET01c and SIBYLL2.1, and heavy dominant (HD) and proton dominant (PD) primary composition models. Pure protonandpureironprimarymodelsarealsoexaminedasextremecases.A detector simulationwasalsoperformedtoimproveouraccuracyindeterminingthesizeof theairshowersandtheenergyof theprimaryparticle.Weconfirmedthatthe all-particle energy spectra obtained under various plausible model parameters are not significantly different from each other, which was the expected result given the characteristics of the experiment at high altitude, where the air showers of the primary energy around the knee reach near-maximum development, with their features dominated by electromagnetic components,leadingtoaweakdependenceontheinteractionmodel or theprimarymass.Thisisthehighest statistical and the best systematics-controlled measurement covering the widest energy range around the knee energy region.
194 citations
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Hirosaki University1, Saitama University2, Chinese Academy of Sciences3, Tibet University4, Shandong University5, Southwest Jiaotong University6, Yunnan University7, Kanagawa University8, Utsunomiya University9, University of Tokyo10, Konan University11, Shibaura Institute of Technology12, Yokohama National University13, Shinshu University14, Shonan Institute of Technology15
TL;DR: In this paper, the sidereal anisotropy of cosmic ray intensity in the multi-TeV region observed with the Tibet-III air shower array during the period from 1999 through 2003 was analyzed.
Abstract: We present the large-scale sidereal anisotropy of Galactic cosmic-ray intensity in the multi-TeV region observed with the Tibet-III air shower array during the period from 1999 through 2003. The sidereal daily variation of cosmic rays observed in this experiment shows an excess of relative intensity around 4-7 hr local sidereal time as well as a deficit around 12 hr local sidereal time. While the amplitude of the excess is not significant when averaged over all declinations, the excess in individual declination bands becomes larger and clearer as the viewing direction moves toward the south. The maximum phase of the excess intensity changes from ~7 hr at the Northern Hemisphere to ~4 hr at the equatorial region. We also show that both the amplitude and the phase of the first harmonic vector of the daily variation are remarkably independent of primary energy in the multi-TeV region. This is the first result determining the energy and declination dependences of the full 24 hr profiles of the sidereal daily variation in the multi-TeV region with a single air shower experiment.
120 citations
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Nanjing University1, University of Turin2, University of Geneva3, Purple Mountain Observatory4, University of Arizona5, Southwest Jiaotong University6, University of Calgary7, Peking University8, Guangxi University9, Istituto Nazionale di Fisica Nucleare10, Shandong University11, Centre national de la recherche scientifique12, Mahidol University13, Russian Academy of Sciences14, National Research Nuclear University MEPhI15, Sun Yat-sen University16, Nanchang University17, Chinese Academy of Sciences18, Xinjiang Astronomical Observatory19, Max Planck Society20, University of Nevada, Las Vegas21, Yunnan University22
TL;DR: The Large High Altitude Air Shower Observatory (LHAASO) project is a new generation multi-component instrument, to be built at 4410 meters of altitude in the Sichuan province of China, with the aim to study with unprecedented sensitivity the spec trum, the composition and the anisotropy of cosmic rays in the energy range between 10$^{12}$ and 10$€18}$ eV, as well as to act simultaneously as a wide aperture (one stereoradiant), continuously operated gamma ray telescope in the EH range between
Abstract: The Large High Altitude Air Shower Observatory (LHAASO) project is a new generation multi-component instrument, to be built at 4410 meters of altitude in the Sichuan province of China, with the aim to study with unprecedented sensitivity the spec trum, the composition and the anisotropy of cosmic rays in the energy range between 10$^{12}$ and 10$^{18}$ eV, as well as to act simultaneously as a wide aperture (one stereoradiant), continuously-operated gamma ray telescope in the energy range between 10$^{11}$ and $10^{15}$ eV. The experiment will be able of continuously surveying the TeV sky for steady and transient sources from 100 GeV to 1 PeV, t hus opening for the first time the 100-1000 TeV range to the direct observations of the high energy cosmic ray sources. In addition, the different observables (electronic, muonic and Cherenkov/fluorescence components) that will be measured in LHAASO will allow to investigate origin, acceleration and propagation of the radiation through a measurement of energy spec trum, elemental composition and anisotropy with unprecedented resolution. The remarkable sensitivity of LHAASO in cosmic rays physics and gamma astronomy would play a key-role in the comprehensive general program to explore the High Energy Universe. LHAASO will allow important studies of fundamental physics (such as indirect dark matter search, Lorentz invariance violation, quantum gravity) and solar and heliospheric physics. In this document we introduce the concept of LHAASO and the main science goals, providing an overview of the project.
119 citations
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TL;DR: In this article, the authors analyzed the events recorded by ARGO-YBJ in more than five years of data collection to determine the diffuse gamma-ray emission in the Galactic plane at Galactic longitudes 25° < l < 100° and Galactic latitudes b 5 ∣ ∣< °.
Abstract: The events recorded by ARGO-YBJ in more than fiveyears of data collection have been analyzed to determine the diffuse gamma-ray emission in the Galactic plane at Galactic longitudes 25° < l < 100° and Galactic latitudes b 5 ∣ ∣< °. The energy range covered by this analysis, from ∼350 GeV to ∼2 TeV, allows the connection of the region explored by Fermi with the multi-TeV measurements carried out by Milagro. Our analysis has been focused on two selected regions of the Galactic plane, i.e., 40° < l < 100° and 65° < l <8 5 °( the Cygnus region), where Milagro observed an excess with respect to the predictions of current models. Great care has been taken in order to mask the most intense gamma-ray sources, including the TeV counterpart of the Cygnus cocoon recently identified by ARGO-YBJ, and to remove residual contributions. The ARGO-YBJ results do not show any excess at sub-TeV energies corresponding to the excess found by Milagro, and are consistent with the predictions of the Fermi model for the diffuse Galactic emission. From the measured energy distribution we derive spectral indices and the differential flux at 1 TeV of the diffuse gamma-ray emission in the sky regions investigated.
74 citations
Cited by
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TL;DR: A survey of the theory and experimental tests for the propagation of cosmic rays in the Galaxy up to energies of 10 15 eV is given in this article, followed by an exposition of basic principles.
Abstract: We survey the theory and experimental tests for the propagation of cosmic rays in the Galaxy up to energies of 10 15 eV. A guide to the previous reviews and essential literature is given, followed by an exposition of basic principles. The basic ideas of cosmic-ray propagation are described, and the physical origin of its processes is explained. The various techniques for computing the observational consequences of the theory are described and contrasted. These include analytical and numerical techniques. We present the comparison of models with data, including direct and indirect—especially γ-ray—observations, and indicate what we can learn about cosmic-ray propagation. Some important topics, including electron and antiparticle propagation, are chosen for discussion.
1,072 citations
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TL;DR: PAMELA data challenge the current paradigm of cosmic-ray acceleration in supernova remnants followed by diffusive propagation in the Galaxy and find that the spectral shapes of these two species are different and cannot be described well by a single power law.
Abstract: Protons and helium nuclei are the most abundant components of the cosmic radiation Precise measurements of their fluxes are needed to understand the acceleration and subsequent propagation of cosmic rays in our Galaxy We report precision measurements of the proton and helium spectra in the rigidity range 1 gigavolt to 12 teravolts performed by the satellite-borne experiment PAMELA (payload for antimatter matter exploration and light-nuclei astrophysics) We find that the spectral shapes of these two species are different and cannot be described well by a single power law These data challenge the current paradigm of cosmic-ray acceleration in supernova remnants followed by diffusive propagation in the Galaxy More complex processes of acceleration and propagation of cosmic rays are required to explain the spectral structures observed in our data
900 citations
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TL;DR: In this paper, the authors discuss the possible mechanisms for the generation of cosmological magnetic fields, discuss their evolution in an expanding universe filled with the cosmic plasma and provide a critical review of the literature on the subject.
Abstract: We review the possible mechanisms for the generation of cosmological magnetic fields, discuss their evolution in an expanding Universe filled with the cosmic plasma and provide a critical review of the literature on the subject. We put special emphasis on the prospects for observational tests of the proposed cosmological magnetogenesis scenarios using radio and gamma-ray astronomy and ultra-high-energy cosmic rays. We argue that primordial magnetic fields are observationally testable. They lead to magnetic fields in the intergalactic medium with magnetic field strength and correlation length in a well defined range. We also state the unsolved questions in this fascinating open problem of cosmology and propose future observations to address them.
662 citations
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Max Planck Society1, Centre national de la recherche scientifique2, University of Hamburg3, Humboldt University of Berlin4, Durham University5, École Polytechnique6, Collège de France7, Dublin Institute for Advanced Studies8, University of Montpellier9, Joseph Fourier University10, DSM11, North-West University12, Ruhr University Bochum13, Charles University in Prague14, University of Namibia15
TL;DR: The distribution in Galactic latitude of the detected sources appears to be consistent with a scale height in the Galactic disk for the parent population smaller than 100 pc, consistent with expectations for supernova remnants and/or pulsar wind nebulae.
Abstract: We report on a survey of the inner part of the Galactic plane in very high energy gamma rays with the H.E.S.S. Cerenkov telescope system. The Galactic plane between +/-30° in longitude and +/-3° in latitude relative to the Galactic center was observed in 500 pointings for a total of 230 hr, reaching an average flux sensitivity of 2% of the Crab Nebula at energies above 200 GeV. Fourteen previously unknown sources were detected at a significance level greater than 4 σ after accounting for all trials involved in the search. Initial results on the eight most significant of these sources were already reported elsewhere (Aharonian and coworkers). Here we present detailed spectral and morphological information for all the new sources, along with a discussion on possible counterparts in other wavelength bands. The distribution in Galactic latitude of the detected sources appears to be consistent with a scale height in the Galactic disk for the parent population smaller than 100 pc, consistent with expectations for supernova remnants and/or pulsar wind nebulae.
586 citations