A5101868631- Astrophysics and Cosmic Phenomena
- Solar and Space Plasma Dynamics
- Dark Matter and Cosmic Phenomena
- Astrophysics and Star Formation Studies
- Gamma-ray bursts and supernovae
- Neutrino Physics Research
- Radio Astronomy Observations and Technology
- Stellar, planetary, and galactic studies
- Organic and Molecular Conductors Research
- Ionosphere and magnetosphere dynamics
- Muon and positron interactions and applications
- Turbomachinery Performance and Optimization
- Geophysics and Gravity Measurements
- Heat Transfer Mechanisms
- Advanced Sensor Technologies Research
- Pulsars and Gravitational Waves Research
- Molecular Junctions and Nanostructures
- Magnetism in coordination complexes
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Fullerene Chemistry and Applications
- Graphene research and applications
- Tribology and Lubrication Engineering
- Particle Accelerators and Free-Electron Lasers
- Radiation Therapy and Dosimetry
Beihang University
2023-2024
Chinese Academy of Civil Aviation Science and Technology
2024
Tsinghua University
2003-2021
National Astronomical Observatories
2003-2021
Chinese Academy of Sciences
2003-2007
University of Chicago
1996-2007
International Space Science Institute
1999
University of Missouri–Kansas City
1992-1997
We report, for the first time, long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in Galactic disk. Particularly, all above 398 are observed apart from known gamma-ray sources compatible expectations hadronic emission scenario which originate decay $π^0$'s produced through interaction protons interstellar medium Galaxy. This is strong evidence that cosmic accelerated beyond our Galaxy spread over
view Abstract Citations (237) References (12) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Modeling Solar Force-free Magnetic Fields Low, B. C. ; Lou, Y. Q. A class of nonlinear force-free magnetic fields is presented, described in terms the solutions to a second-order, ordinary differential equation. These are three-dimensional, filling infinite half-space above plane where lines force anchored. They model sun over active regions with striking geometric...
We present an updated all-particle energy spectrum of primary cosmic rays in a wide range from 1014 to 1017 eV using 5.5 × 107 events collected 2000 November through 2004 October by the Tibet-III air-shower array located 4300 m above sea level (an atmospheric depth 606 g cm−2). The size exhibits sharp knee at corresponding around 4 PeV. This work uses increased statistics and new simulation calculations for analysis. discuss our extensive Monte Carlo model dependencies involved final result,...
We report observations of gamma-ray emissions with energies in the 100 TeV energy region from Cygnus our Galaxy. Two sources are significantly detected directions OB1 and OB2 associations. Based on their positional coincidences, we associate one a pulsar PSR J2032+4127 other mainly wind nebula PWN G75.2+0.1 moving away its original birthplace situated around centroid observed emission. This work would stimulate further studies particle acceleration mechanisms at these sources.
The excitation and time evolution of magnetohydrodynamic (MHD) density waves are studied in a differentially rotating thin gaseous disc embedded with an azimuthal magnetic field. This analysis shows that both fast slow MHD amplified when they swing from leading to trailing configurations, but the amplification factors depend differently on differential rotation. Fast tend be excited discs strong rotation, while expected manifest preferentially almost rigid Surface mass field perturbations...
The electronic structure and the optical properties of organic superconductor \ensuremath{\kappa}-(BEDT-TTF${)}_{2}$Cu(NCS${)}_{2}$ are fully elucidated by means first-principles self-consistent local-density calculation. band effective masses on Fermi surfaces found to be ${\mathit{m}}_{\mathrm{\ensuremath{\alpha}}}^{\mathit{b}\mathrm{*}}$=1.77 m ${\mathit{m}}_{\mathrm{\ensuremath{\beta}}}^{\mathit{b}\mathrm{*}}$=3.50 m, density state at level is 12.8/eV cell. These results quite different...
Positron lifetime experiments have been performed in ${\mathrm{C}}_{60}$ as a function of (1) pressure up to 14.7 kbar, (2) temperature between 10 and 300 K, (3) oxygen 2 atm. Nearly single lifetimes (356 ps, 98%) observed solids. A large lifetime-pressure variation [(9--3\ifmmode\pm\else\textpm\fi{}0.5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}3}$ ${\mathrm{kbar}}^{\mathrm{\ensuremath{-}}1}$] monotonic lifetime-temperature...
Aims. The process of gravitational fragmentation in the L1482 molecular filament California cloud is studied by combining several complementary observations and physical estimates. We investigate kinematic dynamical states this properties dozens dense clumps embedded therein. Methods. present compare line emission J=2--1 J=3--2 transitions 12CO complex, using KOSMA 3-meter telescope. These are complemented with archival data analyses 13CO J=1--0 obtained at Purple Mountain Observatory...
We explore MHD solutions for envelope expansions with core collapse (EECC) isothermal shocks in a quasi-spherical symmetry and outline potential astrophysical applications of such magnetized shock flows. are classified into three classes according to the downstream characteristics near core. Class I those characterized by free-fall collapses towards an shock, while II Larson-Penston (LP) type shock. III novel, sharing both features presence sufficiently strong magnetic field as prerequisite....
We construct magnetohydrodynamic (MHD) similarity rebound shocks joining `quasi-static' asymptotic solutions around the central degenerate core to explore an MHD model for evolution of random magnetic field in supernova explosions. This provides a theoretical basis further studying synchrotron diagnostics, shock acceleration cosmic rays, and nature intense compact objects. The strength space approaches limiting ratio, that is comparable ratio ejecta mass driven out versus progenitor mass,...
The electronic structure and the Fermi surfaces of organic superconductor \ensuremath{\kappa}-(BEDT-TTF${)}_{2}$ Cu[N(CN${)}_{2}$ ]Br are elucidated by first-principles calculations. results show very narrow bands, high state density at level, a small band effective mass 0.${28\mathrm{m}}_{0}$ for closed hole orbit. topological features with multiple sheets more complicated than that Cu(NCS${)}_{2}$ . electron distribution on central C=C double bond reveals nonequivalency two C atoms.
We report the detection of 10 new X-ray filaments using data from Chandra satellite for inner 6' (~15 pc) around Galactic center (GC). All these are characterized by nonthermal energy spectra, and most them have pointlike features at their heads that point inward. Fitted with simple absorbed power-law model, measured flux an individual filament in 2-10 keV band is ~2.8 × 10−14 to 10−13 ergs cm−2 s−1, absorption-corrected luminosity ~1032-1033 s−1 a presumed distance 8 kpc GC. speculate...
Distinct positron lifetimes in ${\mathrm{C}}_{60}$ and ${\mathrm{K}}_{3}$${\mathrm{C}}_{60}$ superconductors are observed: a single lifetime (375 ps) pure ${\mathrm{C}}_{60}$, two (265 425 ${\mathrm{K}}_{3}$${\mathrm{C}}_{60}$. The densities, computed by using the self-consistent orthogonalized linear combination of atomic-orbital band structure ${\mathrm{K}}_{\mathit{x}}$${\mathrm{C}}_{60}$ (x=0, 1,2,3, 6) presented. strong dependence positron-density distribution on amount K doping,...
Two-dimensional angular correlation of annihilation radiation (2D-ACAR) experiments have been performed in a semicrystalline polymer, polyaryl-ether-ether-ketone. The two-dimensional hole structures unstretched and stretched polymers, determined from the momentum distributions, are found to be spherical ellipsoidal, respectively. average radii 2.6 \AA{} sample between 1.9 3.6 sample. Applications 2D-ACAR method image three-dimensional hole, free-volume, cavity molecular systems discussed....
We model the propagation of three‐dimensional, adiabatic, linear Alfvén waves in solar atmosphere and wind, taking into account relevant physical effects, including gravity stratification, thermal conduction, radiative losses, heating (via a phenomenological term). Our magnetohydrodynamic wind also accounts for momentum deposition by spectrum non‐WKB waves. The transmission reflection such has been previously studied variety techniques, calculations based on computation ratio between...
Both fast and slow magnetohydrodynamic (MHD) density waves propagating in a thin rotating magnetized gas disc are investigated. In the tight-winding or WKBJ regime, radial variation of MHD density-wave amplitude during wave propagation is governed by conservation action surface N which travels at relevant group speed Cg. The energy ℰ angular momentum J related to ℰ=ωN J=mN respectively, where ω frequency an inertial frame reference integer m, proportional azimuthal wavenumber, corresponds...
The Andromeda galaxy (also referred to as M31 or NGC 224) shows approximately axisymmetric large-scale structures which are identified here with fast magnetohydrodynamic (MHD) density waves in a simple theoretical model characterized by rotating composite system of massive spherical halo (dark matter included), stellar disc and magnetized gas disc. For MHD inside the Lindblad resonance, enhancements surface mass densities well azimuthal magnetic field all roughly phase. Based on this...
The Tibet air shower array, which has an effective area of 36,900 m2, been in operation at Yangbajing Tibet, China altitude 4,300 m above sea level. In this paper, we will briefly introduce the recent gamma-ray observation with present array and our future plan is called muon detector (MD) project.
Using the two-fluid formalism with polytropic approximation, we examine axisymmetric stability criterion for a composite system of gravitationally coupled stellar and gaseous singular isothermal discs (SIDs). Both SIDs are taken to be infinitely thin in self-consistent steady background rotational equilibrium power-law surface mass densities (∝r−1) flat rotation curves. Recently, Lou & Shen derived exact solutions both non-axisymmetric stationary perturbations such SID proposed Ds...
We compute properties of Alfvénic fluctuations within a wide frequency range (i.e., 10 −6 s −1 ≲ ƒ −2 ) in both high‐ and low‐speed magnetized radial solar winds. In particular, the variations normalized cross helicity σ c , Alfvén ratio R A other relevant quantities associated with are presented analyzed. Because existence critical radius r characteristic for given wind profile, continuous reflection effects clearly manifest at frequencies lower than several times . Since outward...