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Earth and Planetary Physics 2022年第1期6卷 42-51页

作者： Xiao-Dong Wang B.Klecker G.Nicolaou S.Barabash M.Wieser P.Wurz A.Galli f.Cipriani Y.futaana Swedish institute of Space Physics KirunaSweden max-planck institute für extraterrestrische physik GarchingGermany Physics institute University of BernBernSwitzerland ESA/ESTEC Research and Scientific Support DepartmentNoordwijkThe Netherlands

Energetic neutral atoms(ENAs)are produced by the neutralization of energetic ions formed by shock-accelerated gradual solar energetic particle events(SEP).These high-energy ENAs(HENAs)can reach the Earth earlier than the associated SEPs and thus can provide information about the SEPs at the lower *** HENA properties observed at Earth depend on the properties of the coronal mass ejection(CME)-driven shocks that accelerate the *** a model of HENA production in a shock-accelerated SEP event,we semi-quantitatively investigate the energy-time spectrum of HENAs depending on the width,propagation speed,and direction of the shock,as well as the density and ion abundances of the lower *** to the baseline model parameters,the cases with a wider shock width angle or a higher coronal density would increase the HENA flux observed at the Earth,while the case with an Earthpropagating shock shows a softened HENA *** comparison of expected HENA fluxes in different cases with a flight-proven ENA instrument suggests that solar HENAs can feasibly be monitored with current technologies,which could provide a lead time of 2−3 hours for SEPs at a few *** propose that monitoring of solar HENAs could provide a new method to forecast shock-driven SEP events that are capable of significant space weather impacts on the near-Earth environment.

关键词： solar energetic particles energetic neutral atoms space weather numerical simulation

A New X-ray Tidal Disruption Event Candidate with fast Variability

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research in Astronomy and Astrophysics 2022年第5期22卷 28-35页

作者： J.Hampel S.Komossa J.Greiner T.H.reiprich M.freyberg T.Erben Argelander-Institut für Astronomie Aufdem Hugel 71D-53121 BonnGermany max-planck Institut für radioastronomie Auf dem Hugel 69D-53121 BonnGermany National Astronomical Observatories Chinese Academy of ScienceBeijing 100101China max-planck institute für extraterrestrische physik GieBenbachstrasse 1D-85748 GarchingGermany

During a close encounter between a star and a supermassive black hole,the star can get disrupted by the black hole’s tidal forces,resulting in a tidal disruption event(TDE).The accretion of the star’s material onto the black hole produces strong emission in different wavelength *** we report the discovery with the roentgen Satellite(rOSAT)of an X-ray-selected transient source in an optically non-active *** the location r.A.:13h31m57s.66 and decl.:-32°43’19".7 a sudden rise in X-ray luminosity by a factor of 8 within 8 days has been ***,a very soft X-ray spectrum with a blackbody temperature kT=0.1 keV and a peak luminosity of at least 1×10^(43)erg s^(-1)suggests a TDE interpretation,and the observed properties are very similar to previously identified soft X-ray(rOSAT)*** optical spectrum taken of the galaxy at the position of rXJ133157.6324319.7 six years after the X-ray outburst does not show any emission lines as would be expected from a persistent active galactic *** redshift of the galaxy is determined to be 0.051 based on absorption *** is therefore likely a member of the galaxy cluster *** rise in X-ray luminosity happens within 8 days and thus appears to be fast for such an *** X-ray emission was detected 170 days before and 165 days after the event,and none was detected 25 yr later with the Neil Gehrels Swift *** change in X-ray luminosity is at least a factor of 40.

关键词： accretion-black holes-galaxies-tidal disruption-X-ray sources

M dwarf stars—the by-product of X-ray selected AGN candidates

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research in Astronomy and Astrophysics 2012年第4期12卷 443-452页

作者： Yu Bai Yan-Chun Suni Xiang-Tao Hei Yang Chen Jiang-Hua Wui Qing-Kang Li richard f. Green Wolfgang Voges Department of Astronomy Beijing Normal University Beijing 100875 China Kitt Peak National Observatory NOAO Tucson AZ 85726-6732 USA max-planck-institute fur extraterrestrische physik D-85740 Garching Germany

X-ray loud M dwarfs are a major source of by-products （contamination） in the X-ray band of the multiwavelength quasar survey. As a by-product, the low dispersion spectra of 22 M dwarfs are obtained in which the spectra of 16 sources are taken for the first time. The spectral types and distances of the sample are given based on spectral indices CaH2, CaH3, and TiO5. The parameter ζ TiO/CaH is calculated to separate the different metallicity classes among dwarfs, subdwarfs and extreme subdwarfs. We also discuss the distributions in the diagrams of log（L x /L bol ）, the ratio between X-ray and bolometric luminosity versus spectral type and infrared colors.

关键词： spectroscopic — stars: X-rays: M dwarfs

The Multi-Wavelength Quasar Survey IV. Quasars in the Leo Cluster

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Chinese Journal of Astronomy and Astrophysics 2007年第4期7卷 595-600页

作者： Yang Chen Yu Bai Xiang-Tao He Jiang-Hua Wu Jing Wang Qing-Kang Li Yan-Chun Sun richard f. Green Wolfgang Voges Department of Astronomy Beijing Normal University Beijing 100875 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 Large Binocular Telescope Observatory NOAO Tucson AZ85721 USA max-planck-institute fur extraterrestrische physik D-85740 Garching Germany

We aim to provide a quasar sample that is more complete than any previous surveys by using a combined selection technique to reduce the selection effects. Here we present the observational results for the X-ray candidates in the field of the Leo Cluster. We found 33 X-ray AGNs in this field of which 10 are new discoveries. The X-ray data and optical spectra of these AGNs are given. We also study the near-Ir properties of the X-ray-selected AGNs by using the data from 2MASS. Most of the AGNs in our sample span the color range 0.0〈B-J〈2.5,1.0〈 J-Ks 〈2.0 and 0.5〈H-Ks〈1.2.

关键词： galaxies: active: individual (Leo Cluster) - X-rays: galaxies: quasars

Experiments on Gas Jet in the Wendelstein 7-AS Stellarator

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Plasma Science and Technology 2003年第5期5卷 1933-1938页

作者：姚良骅 J.Baldzuhn Southwestern institute of Physics Chengdu 610041China max-planck Institut fuer Plasma physik EURATOM Ass.17491 GreifswaldGermany

Wendelstein 7-AS (W7-AS) pertains to an advanced helical stellarator. A new fuelling method, the supersonic molecular beam injection (SMBI, named Gas Jet in Germany) system was installed in W7-AS in May 2001 as a cooperation research item co-supported by the National Nature Science foundation of China and the max-planck institute of Plasma Physics, Garching, Germany. The experiments of the gas jet with hydrogen or deuterium on W7-AS were implemented. The experimental results exhibit the following features such as high fuelling efficiency, stable high-density plasmas and reduction of the recycling fluxes from the vessel wall during injection. These crucial points show that the new fuelling method can be applied to long and stable discharges.

关键词： gas jet (Supersonic Molecular Beam) injection wendelstein 7-AS stellarator fuelling

Terahertz emission in tenuous gases irradiated by ultrashort laser pulses

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Chinese Physics C 2009年第S2期33卷 142-145页

作者：王伟民盛政明武慧春陈民李春张杰 K. Mima Beijing National Laboratory of Condensed Matter Physics Institute of Physics CAS Department of Physics Shanghai Jiaotong University max-planck-Institut fr Quantenoptik Institut fr Theoretische physik I Heinrich-Heine-Universitt Dsseldorf institute of Laser Engineering Osaka University 2-6 Yamadaoka Suita

Mechanism of terahertz (THz) pulse generation in gases irradiated by ultrashort laser pulses is investigated theoretically. Quasi-static transverse currents produced by laser field ionization of gases and the longitudinal modulation in formed plasmas are responsible for the THz emission at the electron plasma frequency, as demonstrated by particle-in-cell simulations including field ionization. The THz field amplitude scaling with the laser amplitude within a large range is also discussed.

关键词： Terahertz emission ionization of gases plasma formation particle-in-cell simulations

Millimeter gap contrast as a probe for turbulence level in protoplanetary disks

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Science China(Physics,Mechanics & Astronomy) 2022年第12期65卷 131-144页

作者： Yao Liu Gesa H.-M.Bertrang Mario flock Giovanni P.rosotti Ewine f.van Dishoeck Yann Boehler Stefano facchini Can Cui Sebastian Wolf Min fang max-planck-Institut für extraterrestrische physik Garching85748Germany Purple Mountain Observatory&Key Laboratory for radio Astronomy Chinese Academy of SciencesNanjing210023China max-planck-Institut für Astronomie HeidelbergD-69117Germany Leiden Observatory Leiden UniversityLeidenNL-2300the Netherlands School of Physics and Astronomy University of LeicesterLeicesterLE17RHUK UniversitéGrenoble Alpes French National Centre for Scientific ResearchInstitute for Planetary Sciences and AstrophysicsGrenobleGrenobleF-38000France European Southern Observatory Garching85748Germany Department of Applied Mathematics and Theoretical Physics University of CambridgeCentre for Mathematical SciencesCambridgeCB3 OWAUK Institut für Theoretische physik und Astrophysik Christian-Albrechts-Universität zu kielKiel24118Germany

Turbulent motions are believed to regulate angular momentum transport and influence dust evolution in protoplanetary *** the strength of turbulence is challenging through gas line observations because of the requirement for high spatial and spectral resolution data,and an exquisite determination of the *** this work,taking the well-known HD 163296 disk as an example,we investigated the contrast of gaps identified in high angular resolution continuum images as a probe for the level of *** self-consistent radiative transfer models,we simultaneously analyzed the radial brightness profiles along the disk major and minor axes,and the azimuthal brightness profiles of the B67 and B100 *** fitting all the gap contrasts measured from these profiles,we constrained the gas-to-dust scale height ratioΛto be 3.0^(+0.3)_(−0.8),1.2^(+0.1)_(−0.1),and≥6.5 for the D48,B67,and B100 regions,*** varying gas-to-dust scale height ratios indicate that the degree of dust settling changes with *** inferred values forΛtranslate into a turbulence level of α_(turb)regions,which is consistent with previous upper limits set by gas line ***,turbulent motions in the B67 ring are strong with α_(turb)∼1.2×10^(−2).Due to the degeneracy betweenΛand the depth of dust surface density drops,the turbulence strength in the D86 gap region is not constrained.

关键词： protoplanetary disks radiative transfer planet formation

The Multi-Wavelength Quasar Survey III. Quasars in field 836

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Chinese Journal of Astronomy and Astrophysics 2007年第3期7卷 375-379页

作者： Yu Bai Yang Chen Xiang-Tao He Jiang-Hua Wu Qing-Kang Li richard f.Green Wolfgang Voges Department of Astronomy Beijing Normal University Beijing 100875 National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 Kitt Peak National Observatory NOAO Tucson AZ85726-6732 USA max-planck-institute fuer extraterrestrische physik D-85740 Garching Germany

This is the third paper in a series connected with our Multiwavelength Quasar Survey. The survey is aimed to provide a quasar sample more complete than any previous survey by using a combined selection technique to reduce selection effects. We present the observational results for the X-ray candidates in field f836. We found 15 X-ray AGNs in this field of which eight are new discoveries. The X-ray data and optical spectra of these AGNs are given. We give the X-ray candidate selection criteria, which proved to be highly efficient in isolating X-ray AGNs.

关键词： galaxies active individual (field f 836) - X-rays galaxies quasars

XMM-Newton observation of the eclipsing binary Algol

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research in Astronomy and Astrophysics 2011年第4期11卷 457-470页

作者： Xue-Juan Yang fang-Jun Lu Bemd Aschenbach Li Chen faculty of Materials Optoelectronics and Physics Xiangtan University Xiangtan 411105China Particle Astrophysics Center Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China max-planck-Institut fur extraterrestrische physik 85741 Garching Germany Department of Astronomy Beijing Normal University Beijing 100875 China

We present an XMM-Newton observation of the eclipsing binary Algol which contains an X-ray dark B8V primary and an X-ray bright K2IV secondary. The observation covered the optical secondary eclipse and captured an X-ray flare that was eclipsed by the B star. The XMM-Newton European Photon Imaging Camera and reflection Grating Spectrometer spectra of Algol in its quiescent state are described by a two-temperature plasma model. The cool component has a temperature around 6.4× 106 K while that of the hot component ranges from 2 to 4.0× 107 K. Coronal abundances of C, N, O, Ne, Mg, Si and fe were obtained for each component for both the quiescent and the flare phases, generally with upper limits for S and Ar, and upper limits for C, N, and O from the hot component. f-tests show that the abundances do not need to be different between the cool and the hot component and between the quiescent and the flare phase with the exception of fe. Although the fe abundance of the cool component remains constant at -0.14, the hot component shows an fe abundance of -0.28, which increases to -0.44 during the flare. This increase is expected from the chromospheric evaporation model. The absorbing column density NH of the quiescent emission is 2.5 - 1020 cm-2, while that of the flare-only emission is significantly lower and consistent with the column density of the interstellar medium. This observation substantiates earlier suggestions of the presence of X-ray absorbing material in the Algol system.

关键词： stars abundance -- star binaries eclipsing -- stars flare -- stars indi-vidual Algol

Nonadiabatic dynamics and geometric phase of an ultrafast rotating electron spin

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Science Bulletin 2019年第6期64卷 380-384页

作者： Xing-Yan Chen Tongcang Li Zhang-Qi Yin Center for Quantum Information Institute for Interdisciplinary Information Sciences Tsinghua University max-planck-Institut für Quantenoptik fakult?t für physik Ludwig-Maximilians-Universit?t München Department of Physics and Astronomy Purdue University School of Electrical and Computer Engineering Purdue University Purdue Quantum Center Purdue University Birck Nanotechnology Center Purdue University

The spin in a rotating frame has attracted a lot of attentions recently,as it deeply relates to both fundamental physics such as pseudo-magnetic field and geometric phase,and applications such as gyroscopic ***,previous studies only focused on adiabatic limit,where the rotating frequency is much smaller than the spin *** we propose to use a levitated nano-diamond with a built-in nitrogen-vacancy(NV)center to study the dynamics and the geometric phase of a rotating electron spin without adiabatic *** find that the transition between the spin levels appears when the rotating frequency is comparable to the spin frequency at zero magnetic *** we use floquet theory to numerically solve the spin energy spectrum,study the spin dynamics and calculate the geometric phase under a finite magnetic field,where the rotating frequency to induce resonant transition could be greatly reduced.

关键词： Nitrogen-vacancy center Nonadiabatic geometric phase Ultrafast rotor rabi oscillation Optomechanics