Author
Masaomi Ono
Other affiliations: Yukawa Institute for Theoretical Physics, Kyoto University
Bio: Masaomi Ono is an academic researcher from Kyushu University. The author has contributed to research in topics: Supernova & Cosmic ray. The author has an hindex of 28, co-authored 104 publications receiving 2452 citations. Previous affiliations of Masaomi Ono include Yukawa Institute for Theoretical Physics & Kyoto University.
Papers
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University of Utah1, Saitama University2, Tokyo Institute of Technology3, Ewha Womans University4, Hanyang University5, Tokyo University of Science6, Kindai University7, Yonsei University8, University of Tokyo9, Osaka City University10, Kanagawa University11, University of Yamanashi12, Tokyo City University13, Waseda University14, Chiba University15, Kōchi University16, Ritsumeikan University17, Sungkyunkwan University18, Université libre de Bruxelles19, Ulsan National Institute of Science and Technology20, Rutgers University21, Hiroshima City University22, National Institute of Radiological Sciences23, Ehime University24
TL;DR: In this paper, the authors search for intermediate-scale anisotropy in the arrival directions of ultra-high-energy cosmic rays with energies above 57 EeV in the northern sky using data collected over a 5-year period by the surface detector of the Telescope Array experiment.
Abstract: We have searched for intermediate-scale anisotropy in the arrival directions of ultrahigh-energy cosmic rays with energies above 57 EeV in the northern sky using data collected over a 5 yr period by the surface detector of the Telescope Array experiment. We report on a cluster of events that we call the hotspot, found by oversampling using 20° radius circles. The hotspot has a Li-Ma statistical significance of 5.1σ, and is centered at R.A. = 146.°7, decl. = 43.°2. The position of the hotspot is about 19° off of the supergalactic plane. The probability of a cluster of events of 5.1σ significance, appearing by chance in an isotropic cosmic-ray sky, is estimated to be 3.7 × 10-4 (3.4σ). © 2014. The American Astronomical Society. All rights reserved.
348 citations
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TL;DR: In this paper, the authors search for intermediate-scale anisotropy in the arrival directions of ultra-high-energy cosmic rays with energies above 57~EeV in the northern sky using data collected over a 5 year period by the surface detector of the Telescope Array experiment.
Abstract: We have searched for intermediate-scale anisotropy in the arrival directions of ultrahigh-energy cosmic rays with energies above 57~EeV in the northern sky using data collected over a 5 year period by the surface detector of the Telescope Array experiment. We report on a cluster of events that we call the hotspot, found by oversampling using 20$^\circ$-radius circles. The hotspot has a Li-Ma statistical significance of 5.1$\sigma$, and is centered at R.A.=146.7$^{\circ}$, Dec.=43.2$^{\circ}$. The position of the hotspot is about 19$^{\circ}$ off of the supergalactic plane. The probability of a cluster of events of 5.1$\sigma$ significance, appearing by chance in an isotropic cosmic-ray sky, is estimated to be 3.7$\times$10$^{-4}$ (3.4$\sigma$).
251 citations
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University of Utah1, Saitama University2, Tokyo Institute of Technology3, Ewha Womans University4, Hanyang University5, Tokyo University of Science6, Kindai University7, Yonsei University8, University of Tokyo9, Osaka City University10, Kanagawa University11, University of Yamanashi12, Tokyo City University13, Waseda University14, Chiba University15, Kōchi University16, Ritsumeikan University17, Sungkyunkwan University18, Moscow State University19, Université libre de Bruxelles20, Rutgers University21, Hiroshima City University22, National Institute of Radiological Sciences23, Ehime University24
TL;DR: In this paper, the authors compare the results of the HiRes and PAO UHECR measurements to the results obtained by the QGSJetII-03 and QGS jet-01c models.
215 citations
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University of Utah1, Saitama University2, Tokyo Institute of Technology3, Hanyang University4, Tokyo University of Science5, Kindai University6, University of Tokyo7, Osaka City University8, Shinshu University9, Kanagawa University10, University of Yamanashi11, Sungkyunkwan University12, Tokyo City University13, Russian Academy of Sciences14, Waseda University15, Chiba University16, Yonsei University17, Institute for the Physics and Mathematics of the Universe18, Kōchi University19, Ritsumeikan University20, Ulsan National Institute of Science and Technology21, Rutgers University22, Osaka Electro-Communication University23, Hiroshima City University24, KEK25, Ewha Womans University26, Ehime University27
TL;DR: In this paper, the authors compare the means and standard deviations of the observed $X_{\mathrm{max}}$ distributions with Monte Carlo distributions of unmixed protons, helium, nitrogen, and iron, all generated using the QGSJet~II-04 hadronic model.
Abstract: The Telescope Array observatory utilizes fluorescence detectors and surface detectors to observe air showers produced by ultra high energy cosmic rays in the Earth's atmosphere Cosmic ray events observed in this way are termed hybrid data The depth of air shower maximum is related to the mass of the primary particle that generates the shower This paper reports on shower maxima data collected over 85 years using the Black Rock Mesa and Long Ridge fluorescence detectors in conjunction with the array of surface detectors We compare the means and standard deviations of the observed $X_{\mathrm{max}}$ distributions with Monte Carlo $X_{\mathrm{max}}$ distributions of unmixed protons, helium, nitrogen, and iron, all generated using the QGSJet~II-04 hadronic model We also perform an unbinned maximum likelihood test of the observed data, which is subjected to variable systematic shifting of the data $X_{\mathrm{max}}$ distributions to allow us to test the full distributions, and compare them to the Monte Carlo to see which elements are not compatible with the observed data For all energy bins, QGSJet~II-04 protons are found to be compatible with Telescope Array hybrid data at the 95% confidence level after some systematic $X_{\mathrm{max}}$ shifting of the data Three other QGSJet~II-04 elements are found to be compatible using the same test procedure in an energy range limited to the highest energies where data statistics are sparse
95 citations
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University of Utah1, Saitama University2, Tokyo Institute of Technology3, Hanyang University4, Tokyo University of Science5, Kindai University6, Université libre de Bruxelles7, University of Tokyo8, Osaka City University9, Shinshu University10, Kanagawa University11, University of Yamanashi12, Sungkyunkwan University13, Tokyo City University14, Waseda University15, Chiba University16, Yonsei University17, Kōchi University18, Ritsumeikan University19, Moscow State University20, Ulsan National Institute of Science and Technology21, Rutgers University22, Osaka Electro-Communication University23, Hiroshima City University24, National Institute of Radiological Sciences25, Academy of Sciences of the Czech Republic26, Ewha Womans University27, Ehime University28
82 citations
Cited by
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28,685 citations
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TL;DR: In this paper, the authors describe new optically thin solutions for rotating accretion flows around black holes and neutron stars, which are advection dominated, so that most of the viscously dissipated energy is advected radially with the flow.
Abstract: We describe new optically thin solutions for rotating accretion flows around black holes and neutron stars. These solutions are advection dominated, so that most of the viscously dissipated energy is advected radially with the flow. We model the accreting gas as a two temperature plasma and include cooling by bremsstrahlung, synchrotron, and Comptonization. We obtain electron temperatures $T_e\sim 10^{8.5}-10^{10}$K. The new solutions are present only for mass accretion rates $\dot M$ less than a critical rate $\dot M_{crit}$ which we calculate as a function of radius $R$ and viscosity parameter $\alpha$. For $\dot M<\dot M_{crit}$ we show that there are three equilibrium branches of solutions. One of the branches corresponds to a cool optically thick flow which is the well-known thin disk solution of Shakura \& Sunyaev (1973). Another branch corresponds to a hot optically thin flow, discovered originally by Shapiro, Lightman \& Eardley (1976, SLE). This solution is thermally unstable. The third branch corresponds to our new advection-dominated solution. This solution is hotter and more optically thin than the SLE solution, but is viscously and thermally stable. It is related to the ion torus model of Rees et al. (1982) and may potentially explain the hard X-ray and $\gamma$-ray emission from X-ray binaries and active galactic nuclei.
1,088 citations
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TL;DR: A comprehensive review of major developments in our understanding of gamma-ray bursts, with particular focus on the discoveries made within the last fifteen years when their true nature was uncovered, can be found in this paper.
864 citations
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TL;DR: A comprehensive review of major developments in the understanding of gamma-ray bursts can be found in this article, with particular focus on the discoveries made within the last fifteen years when their true nature was uncovered.
Abstract: We provide a comprehensive review of major developments in our understanding of gamma-ray bursts, with particular focus on the discoveries made within the last fifteen years when their true nature was uncovered. We describe the observational properties of photons from the radio to multi-GeV bands, both in the prompt emission and the afterglow phases. Mechanisms for the generation of these photons in GRBs are discussed and confronted with observations to shed light on the physical properties of these explosions, their progenitor stars and the surrounding medium. After presenting observational evidence that a powerful, collimated, jet moving at close to the speed of light is produced in these explosions, we describe our current understanding regarding the generation, acceleration, and dissipation of the jet and compare these properties with jets associated with AGNs and pulsars. We discuss mounting observational evidence that long duration GRBs are produced when massive stars die, and that at least some short duration bursts are associated with old, roughly solar mass, compact stars. The question of whether a black-hole or a strongly magnetized, rapidly rotating neutron star is produced in these explosions is also discussed. We provide a brief summary of what we have learned about relativistic collisionless shocks and particle acceleration from GRB afterglow studies, and discuss the current understanding of radiation mechanism during the prompt emission phase. We discuss theoretical predictions of possible high-energy neutrino emission from GRBs and the current observational constraints. Finally, we discuss how these explosions may be used to study cosmology, e.g. star formation, metal enrichment, reionization history, as well as the formation of first stars and galaxies in the universe.
814 citations
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TL;DR: This is really two separate books within the same pair of covers, which are devoted to the discussion of similarity and dimensional, methods and their application to a variety of problems in mechanics and fluid mechanics.
Abstract: By L I Sedov London: Cleaver-Hume Press Ltd Pp xvi + 363 Price 105s This is really two separate books within the same pair of covers First of all Chapters 1-3, some 145 pages, are devoted to the discussion of similarity and dimensional, methods and their application to a variety of problems in mechanics and fluid mechanics
697 citations