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astronomical function and date of the Taosi observatory

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Science China(Physics,Mechanics & Astronomy) 2009年第1期52卷 151-158页

作者： WU JiaBi1, CHEN MeiDong2.& LIU CiYuan3 1 National astronomical Observatories, chinese academy of sciences,{2., China 2.Institute for the History of Natural Science, chinese academy of sciences, beijing 100010, China 3 National Time Service Center, chinese academy of sciences, Xi’an 710600, China 1. National astronomical Observatories Chinese Academy of Sciences Beijing 100012 China 2. Institute for the History of Natural Science Chinese Academy of Sciences Beijing 100010 China 3. National Time Service Center Chinese Academy of Sciences Xi’an 710600 China

The Taosi site in Xiangfen County,Shanxi Province,may be the capital of the King yao. Archeologists recently discovered a large semi-circular stamped-earth platform, II FJT1,which has a clear and definite pounded-earth central core together with a curved wall perforated by twelve gaps. The platform is said to be an ancient observatory used to determine the seasons by watching the sunrise. Each feature of II FJT1 was precisely measured and the data are reproduced in this paper. An astronomical analysis of slots E2.and E12.was carried out using the azimuths of the slots' centerlines and the vertical angle of the mountain ridge opposite, above which the sun rises. The results show that at present the sun is close to the two slots but does not exactly enter them at summer and winter solstice sunrise. Using 14C analysis archeologists dated the site to about 2.00 BC. Because of the secular change in the obliquity of the ecliptic,at that date on the summer solstice the half-risen sun would have appeared inside slot E12.just to the right of the centerline,and on the winter solstice the sun would have been exactly on the centerline of slot E2. This result provides compelling proof that II FJT1 is an ancient observatory.

关键词： astro-archeology astro-chronology Taosi culture ancient observatory time service

Do Globular Clusters Harbor Black Holes?

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chinese Journal of Astronomy and Astrophysics 2001年第4期1卷 291-295页

作者： Xian-Zhong Zheng (National astronomical Observatories, chinese academy of sciences,{2.)E-mail:zxz@*** National astronomical Observatories Chinese Academy of Sciences Beijing 100012

It has been firmly established that there exists a tight correlation be- tween the mass of the central black hole and velocity dispersion (or luminosity) in elliptical galaxies, 'pseudobulges' and bulges of galaxies, although the nature of this correlation still remains nuclear. We explore the possibility of extrapolating such a correlation to less massive, spherical systems like globular clusters. In particular, motivated by the apparent success in the globular cluster M15, we present an estimate of the central black hole mass for a number of globular clusters with available velocity dispersion data.

关键词： black hole physics-globular clusters: general - galaxies: general

A new method for imaging faint objects nearby a bright source

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chinese Science Bulletin 2000年第3期45卷 201-207页

作者： YE Binxun & CHU Yi1. beijing astronomical Observatory,{2., beijing 100012, China 2. NAOCAS, beijing 100012, China 3. Department of Astronomy, Nanjing University, Nanjing China Correspondence should be addressed to Ye Binxun beijing astronomical Observatory Chinese Academy of Sciences Beijing China NAOCAS Beijing China Department of Astronomy Nanjing University Nanjing China

In astronomical observation, it is difficult to obtain the image of faint objects in the peripheral area around a bright celestial body. in order to solve the problem, a new method is designed and experimented, which is called the separation readout technique (SRT). SRT is different from either the traditional coronagraphy or the newly-developed anti-blooming CCD technique, and allows an enough-long exposure to the faint objects in the area around a bright celestial body with the well-preserved bright body’s image in one frame. This paper describes in detail the principle of SRT, the computer simulation, the experimental devising and result of SRT observation on a telescope.

关键词： astronomyical methods CCD imaging SRT.

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 {2. 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

Time-variation of the near 5-month period of sunspot numbers

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chinese Science Bulletin 2002年第23期47卷 1969-1973页

作者： HAN Yanben1 & HAN Yonggang1,2.. National astronomical Observatories, chinese academy of sciences,{2., China 2. Department of Applied Mathematics, beijing Polytechnic University, beijing 10002., China National astronomical Observatories Chinese Academy of Sciences Beijing China Department of Applied Mathematics Beijing Polytechnic University Beijing China

The variation of the near 5-month period of sunspot numbers is discussed on the basis of the wavelet transform of the daily sunspot number series in the 14th-2.nd solar cycles. The result shows that the period exists in every cycle and its energy density (amplitude) is comparatively large in the peak section of the cycle. In the distinct cycle, the length and intensity of the period is different, which means that the period varies with time. The near 2.-day period is also analyzed and it is found to be time-variable and even not very stable in the peak section of the cycle. The variations of the two periods show that the near 5-month period should not be simply regarded as the multiples of the near 2.-day period.

关键词： solar activity sunspot time-variation wavelet.

A black hole preying on the star for a gamma-ray burst of GRB080503:Evidence for the second event in this new class

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Science China(Physics,Mechanics & Astronomy) 2010年第S1期53卷 117-119页

作者： LU Ye & GAO He National astronomical Observatories,chinese {2. of sciences,beijing 100012,China 1. National astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

In this paper,we critically assess GRB080503,a short gamma-ray burst with very bright extended emission(about 30 times the gamma-ray fluence of the initial spike).The light curve of the prompt γ-ray emission of GRB080503 resembles that of GRB 060614 which has been suggested to be due to an event from an intermediate mass black hole(IMBH) preying on a *** therefore propose that GRB080503 is also due to a similar event;the mass of the IMBH is estimated to be about 4.6×104 solar masses,and the engulfed star had about the same mass and size as the *** also estimate that the total burst energy is about 7.67× 1050 ergs.

关键词： gamma rays:bursts GRB080503 GRB060614-type

The Influence of Panel Gaps on the System NoiseTemperature of the FAST

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chinese Journal of Astronomy and Astrophysics 2001年第2期1卷 190-194页

作者： Yan Su and Guo-Ding Li (1 beijing astronomical Observatory, National astronomical Observatories, chinese academy of sciences, beijing 100012 2.The Laboratory of Microwave and Digital Communication Technology, Tsinghua University, beijing 100084) The Laboratory of Microwave and Digital Communication Technology Tsinghua University Beijing 100084

A Five-hundred-meter Aperture Spherical Telescope (FAST), the largest single dish in the world, is proposed to be built in one of the karst depressions in Guizhou province. The main spherical reflector is to consist of about two thousand small panels, which can be adjusted to fit a paraboloid in real time. There are many slit-like gaps across the aperture due to manufacturing errors thermal effects and deviations between a sphere and a paraboloid. The influence of the energy leakage of the narrow gaps on the system noise temperature of the FAST reflector is discussed in this paper.

关键词： telescopes - methods: analytical - energy leakage

Expectation for the X-ray Galactic Halo

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chinese Journal of Astronomy and Astrophysics 2002年第2期2卷 112-116页

作者： Zhi-Ying Huo National astronomical Observatories, chinese academy of sciences,{2. Department of Physics, Tianjin Normal University, Tianjin 300073 National astronomical Observatories Chinese Academy of Sciences Beijing 100012 []Department of Physics Tianjin Normal University Tianjin 300073

We present an estimate of the strength and spectrum of the X-ray background from the warm gas associated with the Galactic halo. This investigation is motivated primarily by the recent detection of a spatially variable soft X-ray component towards the north Galactic polar cap by Kuntz et al. (2.01), suggesting that the warm gas heated by gravitational shocks of the Galactic halo may produce a significant contribution to the soft X-ray sky. Another purpose of the study is to refine the recent theoretical prediction of the X-ray spectrum from the Galactic halo by Xue (2.01) who adopted an ideal and simple isothermal model for the gas and dark matter distributions of the Galactic halo. We use the universal density profile for the dark matter distributions of the Galactic halo to evaluate the X- ray properties of the warm gas either in hydrostatic equilibrium with, or tracing the underlying gravitational potential of the Galaxy. It has been shown that our prediction is consistent with the measured soft X-ray component towards the north Galactic polar cap if the gas fraction is taken to be^0.005.

关键词： cosmology: diffuse radiation -Galaxy: formation - X-rays: galaxies

Is the Variable X-ray Source in M82.due to Gravitational Lensing?

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chinese Journal of Astronomy and Astrophysics 2001年第4期1卷 287-290页

作者： Da-Ming Chen (National astronomical Observatories, chinese academy of sciences,{2.)E-mail:dmchen66@*** National astronomical Observatories Chinese Academy of Sciences Beijing 100012

We explore the possibility of attributing the recent discovery of the variable hard X-ray source CXO M82.J095550.2.694047 in M82.to the gravitational magnification by an intervening stellar object along the line of sight acting as a microlens. The duration of the event (> 84 days) allows us to set robust constraints on the mass and location of the microlensing object when combined with the dynamical properties of the Galactic halo, M82.and typical globular clusters. Except for the extremely low probability, the microlensing magnification by MACHO in either the Galactic halo or M82.halo is able to explain the X-ray variability of CXO M82.J095550.2.694047. It is hoped that the lensing hypothesis can be tested soon by measurement of the light curve.

关键词： X-rays: stars - Galaxies: individual: M82.- gravitational lensing