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Entropy of three-dimensional BTZ black holes

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中国科学：物理学、力学、天文学英文版 2004年第3期47卷 277-283页

作者： GAO Changjun1,2 & SHEN Yougen1,2,3,4 1.Shanghai astronomical Observatory,chinese academy of sciences,Shanghai 200030,china(mailing address) 2.national astronomical observatories,chinese academy of sciences,beijing 100012,china 3.Institute of Theoretical Physics,chinese academy of sciences,beijing 100080,china 4.Shanghai United Center for Astrophysics,Shanghai 200234,china Shanghai astronomical Observatory Chinese Academy of Sciences Shanghai China national astronomical observatories Chinese Academy of Sciences Beijing China Institute of Theoretical Physics Chinese Academy of Sciences Beijing China Shanghai United Center for Astrophysics Shanghai China

The entropies of scalar field and neutrino field are calculated in the background of three-dimensional BTZ black hole. Considering statistical physics,we propose not to consider the superraradiant modes for bosons (Fermion fields do not display supperradiance).In fact,the nonsuperradiant modes do contribute exactly the area entropy for both bosons and fermions. The result shows that the neutrino field entropy is 3/2 times the scalar one.

关键词： BTZ black holes, entropy, supperradiant modes.

Stochastic Particle Acceleration in Blazar Jets

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chinese Journal of Astronomy and Astrophysics 2002年第1期2卷 1-7页

作者： Jian-Cheng Wang Yunnan Observatory Chinse academy of sciences, Kunming 650011 national astronomical observatories, chinese academy of sciences, beijing 100012 United Laboratory of Optical Astronomy chinese academy of sciences Extragalactic astronomy Recei Yunnan Observatory Chinese Academy of Sciences Kunming 650011 national astronomical observatories Chinese Academy of Sciences Beijing 100012 United Laboratory of Optical Astronomy Chinese Academy of Sciences

The bulk kinetic energy of jets can be dissipated via generating tur- bulen plasma waves. We examine stochastic particle acceleration in blazar jets to explain the emissions of all blazars. We show that acceleration of electrons by plasma turbulence wavs with a spectrum W(k) ~ k^(-4/3) produces a nonthermal population of relativistic electrons whose peak frequency of synchrotron emission can fit the observational trends in the spectral energy distribution of all blazars. The plasma nonlinear processes responsible for the formation of turbulent spectrum are investigated. Increases in the ioteraction time of turbulent waves can produce a fiatter spectrum leading to efficient particle acceleration.

关键词： acceleration of paxticles - blazars: theory - plasma: turbulence - radiation mechanism: nonthermal

Wavelet analysis of sunspot relative numbers

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chinese Science Bulletin 2002年第7期47卷 609-612页

作者： HAN Yanben & HAN Yonggangnational astronomical observatories, chinese academy of sciences, beijing 100012, china Department of Applied Mathematics, beijing Polytechnic University, beijing 100022, china national astronomical observatories Chinese Academy of Sciences Beijing China Department of Applied Mathematics Beijing Polytechnic University Beijing China

The time series of the monthly smoothed sun-spot numbers in 1749-2000 is analyzed with the wavelet. The result shows that besides the known time-variation of the period about 11 years, other main periods of the sunspot numbers, such as the periods of about 100 years and so on, vary with time. We suggest that the time-variation of the main periods is the manifestation of the complex variation of sunspot numbers. It is significant to make a thorough study of the character and mechanism of the time-variation of the periods for proving prediction of sunspot numbers, especially for understanding the variation process of sunspot numbers.

关键词： sunspot numbers prediction wavelet time-variation.

Calculations for the Pre-Calibration of LAMOST Active Optics

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chinese Journal of Astronomy and Astrophysics 2005年第3期5卷 302-314页

作者： Yong Zhang and Xiang-Qun Cui national astronomical observatories / Nanjing Institute of astronomical Optics & Technology, chinese academy of sciences, Nanjing 210042 Graduate School of the chinese academy of sciences, beijing 100039 national astronomical observatories / Nanjing Institute of astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 Graduate School of the chinese academy of sciences Beijing 100039

Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) is one of the major on-going national large scientific projects in china. Active optics is a key technology for the LAMOST with which the thin-mirror active optics and segmented-mirror active optics are tied in. A pre-calibration method considering all active forces and displacements specially for LAMOST has been developed in early 2004. We give a detailed mathematical derivation and calculation including numerical simulation and computer program realization of the pre-calibration method of LAMOST open-loop control for the third-order aspherical aberration. We have also carried out calculations on the application of the pre-calibration method and the parameters of actuator design in LAMOST active optics in observation mode, including estimations of the actuator ranges, the interval of active optics correction and the ranges and trends of load changes on all the actuators during LAMOST tracking a given star.

关键词： active optics telescopes instrumentation

Possible effect of solar activity on variation of the tree-rings of a 500 a platycladus orientalis at the Mausoleum of Emperor Huang

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Science china(Physics,Mechanics & Astronomy) 2009年第4期52卷 631-639页

作者： FENG Bo1,2 & HAN YanBen1 1 Xi’an Institute of Posts & Telecommunications,Xi’an 710061,china 2 national astronomical observatories,chinese academy of sciences,beijing 100012,china Xi’an Institute of Posts & Telecommunications Xi’an China national astronomical observatories Chinese Academy of Sciences Beijing China

The variation of the tree-ring's index of a platycladus orientalis at the Mausoleum of Emperor Huang and of a long series of sunspots relative number during AD1470-1974 are analyzed by using the wavelet power spectrum method,and their variation characters are also discussed. It is determined that the tree-ring's variation has cycles of approximate 2-7,11,93 and 150 a. Two data series are used for analyzing sunspot relative number(SSN) variation. First,the analysis of the annual average SSN during AD1700-1974 proved that variation cycles are about 11,50,and 93 a; then,the data during AD1465-1975 obtained from the decadal average SSN train over 7000 a reconstructed on the geomagnetic data is analyzed and its variation cycles are about 50,90,and 160 a. Besides the tree-rings cycle of 2-7 a is commonly considered to be related to ENSO,while 11 a cycle is related to solar Schwabe cycle; in addition,it is possible that the cycles of 90 and150 a are likely to be related to solar Gleissberg cycle and Suess cycle. The correlations between them are possibly due to the effect of solar activity on the climate and additionally on the tree's growth.

关键词： tree-ring solar activity climate change wavelet spectrum

A new method of ionospheric-free hybrid differential positioning based on a double-antenna CAPS receiver

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Science china(Physics,Mechanics & Astronomy) 2009年第3期52卷 368-375页

作者： GUO JinYun1,2, HAN YanBen1 & CHANG XiaoTao3 1 national astronomical observatories, chinese academy of sciences, beijing 100012, china 2 College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao 266510, china 3 chinese academy of Surveying and Mapping, beijing 100039, china national astronomical observatories Chinese Academy of Sciences Beijing China College of Geodesy and Geomatics Shandong University of Science and Technology Qingdao China chinese academy of Surveying and Mapping Beijing China

chinese Area Positioning System (CAPS) is a transmitted satellite navigation system moved by the chinese academy of sciences. Three basic modes of navigation and positioning with CAPS are given, and then a comparative analysis is made in this paper. In terms of the principle that the ionospheric delay is at an inverse ratio to the frequency square, a new ionospheric-free positioning method based on a double-antenna CAPS receiver is put forward. Then the hybrid differential observations and the solving equations and algorithms for one epoch and multi epochs are deduced according to the basic principle of the method. The method may remove the global errors in signal emission, propagation, transmission and receiving (e.g., ionospheric delay, hardware delay, and clock error). So it is very convenient for the single-epoch solution and multi-epoch navigation and positioning, and may efficiently improve the precision of real time CAPS navigation. Furthermore, the method can be used not only for the geometric orbit determination of CAPS GEO and IGSO satellites and the navigation and positioning, but also for the estimation of the tropospheric zenith delay, which is useful for the study of water vapor changes in the atmosphere. Polynomials are used in this method to express the tropospheric zenith delay and CAPS satellite orbits within the limited time interval, which reduces the num- ber of unknown parameters and thus speeds the computation.

关键词： chinese Area Positioning System (CAPS) ionospheric-free linear combination double-antenna receiver hybrid differential positioning method

A Filament-Associated Halo Coronal Mass Ejection

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chinese Journal of Astronomy and Astrophysics 2001年第1期1卷 85-98页

作者： Jun Zhang, Jingxiu Wang, and Nariaki Nitta ( beijing astronomical Observatory, national astronomical observatories,chinese academy of sciences, beijing 100012 Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, CA 94304, USA) beijing astronomical Observatory National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 Lockheed Martin Solar and Astrophysics Laboratory Palo Alto CA 94304 USA

There are only a few observations published so far that show the initiation of a coronal mass ejection (CME) and illustrate the magnetic changes in the surface origin of a CME. Any attempt to connect a CME with its local solar activities is meaningful. In this paper we present a clear instance of a halo CME initiation. A careful analysis of magnetograms shows that the only obvious magnetic changes in the surface region of the CME is a magnetic flux cancellation underneath a quiescent filament. The early disturbance was seen as the slow upward motion in segments of the quiescent filament. Four hours later, the filament was accelerated to about 50 km s-1 and erupted. While a small part of the material in the filament was ejected into the upper corona, most of the mass was transported to a nearby region. About forty minutes later, the transported mass was also ejected partially to the upper corona. The eruption of the filament triggered a two-ribbon flare, with post-flare loops connecting the flare ribbons. A halo CME, which is inferred to be associated with the eruptive filament, was observed from LASCO/C2 and C3. The halo CME contained two CME events, each event corresponded to a partial mass ejection of the filament. We suggest that the magnetic reconnection at the lower atmosphere is responsible for the filament eruption and the halo CME.

关键词： Sun: filament - Sun: magnetic fields-Sun: coronal mass ejection

Spectroscopic study of globular clusters in the halo of M31 with the Xinglong 2.16 m telescope

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Research in Astronomy and Astrophysics 2011年第11期11卷 1298-1310页

作者： Zhou Fan1,2,Ya-Fang Huang1,2,Jin-Zeng Li1,2,Xu Zhou1,2,Jun Ma1,2,Hong Wu1,2,Tian-Meng Zhang1,2 and Yong-Heng Zhao1,2 1 national astronomical observatories,chinese academy of sciences,beijing 100012,china 2 Key Laboratory of Optical Astronomy,national astronomical observatories,chinese academy of sciences,beijing 100012,china national astronomical observatories Chinese Academy of Sciences Beijing 100012 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present spectroscopic observations for 11 confirmed globular clusters(GCs) of M31 with the OMR spectrograph on the 2.16 m telescope at the Xinglong site of national astronomical observatories,chinese academy of *** of our sample clusters are located in the halo of M31 and the most remote one is out to a projected radius of 78.75 kpc from the galactic *** all our sample clusters,we measured the Lick absorption-line indices and radial *** is noted that most GCs in our sample are distinct from the HI rotation curve of galaxy M31,especially for B514,MCGC5,H12 and B517,suggesting that most of our sample clusters do not have a kinematic association with the star-forming young disk of the *** separately fitted the absorption line indices from the updated stellar population model of Thomas et *** two different tracks of Cassisi and Padova,by applying the χ2 minimization *** fitting results show that all our sample clusters are older than 10 Gyr,and metal-poor(2.38 ≤ [Fe/H] ≤ 0.91 dex).After merging the spectroscopic metallicity of our work with the previously published ones,we extended the cluster sample out to a projected radius of 117 kpc from the galaxy's *** found the metallicity gradient exists for all the confirmed clusters with a slope of 0.028 ± 0.001 dex kpc ***,the slope turns out to be 0.018 ± 0.001 dex kpc 1 for all the halo clusters,which is much *** we only consider the outer halo clusters with rp > 25 kpc,the slope becomes 0.010 ± 0.002 dex kpc 1 and if one cluster G001 is excluded from the outer halo sample,the slope is 0.004 ± 0.002 dex kpc ***,we conclude that the metallicity gradient for M31's outer halo clusters is not significant,which agrees well with previous findings.

关键词： galaxies individual(M31) — galaxies star clusters — globular clusters general — star clusters general

The effects of BCGs on the statistics of large-separation lensed quasars by clusters

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Research in Astronomy and Astrophysics 2011年第9期11卷 1003-1018页

作者： Hong Qi Da-Ming Chen national astronomical observatories Chinese Academy of Sciences Beijing 100012 China

We study the statistics of large-separation multiply-imaged quasars lensed by clusters of galaxies. In particular, we examine how the observed brightest cluster galaxies （BCGs） affect the predicted numbers of wide-separation lenses. We model the lens as an NFW-profiled dark matter halo with a truncated singular isothermal sphere to represent the BCG in its center. We mainly make predictions for the Sloan Digital Sky Survey Quasar Lens Search （SQLS） sample from the Data Release 5 （DRS） in two standard ACDM cosmological models： a model with matter density ΩM = 0.3 and δ8 = 0.9, as is usually adopted in the literature （ACDM1）, and a model suggested by the WMAP seven-year （WMAPT） data with ΩM = 0.266 and δ8 = 0.801. We also study the lensing properties for the WMAP3 cosmology in order to compare with the previous work. We find that BCGs in the centers of clusters significantly enhance the lensing efficiency by a factor of 2 - 3 compared with that of NFW-profiled pure dark matter halos. In addition, the dependence of mass ratios of BCGs to their host halos on the host halo masses reduces the lensing rate by - 20% from assuming a constant ratio as in previous studies, but considering the evolution of this ratio with redshift out to z - 1 would reduce it by - 3%. Moreover, we predict that the numbers of lensed quasars with image separations larger than 10″ in the statistical sample of SQLS from DR5 are 1.22 and 0.47, respectively for ACDM1 and WMAP7 and 0.73 and 0.33 for separations between 10″ and 20″, which are consistent with the only observed cluster lens with such a large separation in the complete SQLS sample.

关键词： cosmological parameters -- cosmology: theory -- galaxies: clusters -- gravitational lensing -- dark matter