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Focal plane wave-front sensing algorithm for high-contrast imaging

Science china(Physics,Mechanics & Astronomy) 2009年第8期52卷 1284-1288页

作者： DOU JiangPei1,2,3.REN DeQing1,2,4,ZHU YongTian1,2 & ZHANG Xi1,2,3.1 national astronomical observatories/Nanjing Institute of astronomical Optics & Technology,chinese academy of Sciences,Nanjing 210042,china 2 Key Laboratory of astronomical Optics & Technology,Nanjing Institute of astronomical Optics & Technology,chinese academy of Sciences,Nanjing 210042,china 3.Graduate University of chinese academy of Sciences,Beijing 100049,china 4 Physics & Astronomy Department,California State University Northridge,18111 Nordhoff Street,Northridge,California 913.0-8268,USA national astronomical observatories/Nanjing Institute of astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China Key Laboratory of astronomical Optics & Technology Nanjing Institute of Astronomical Optics & Technology Chinese Academy of Sciences Nanjing 210042 China Graduate University of chinese academy of Sciences Beijing 100049 China Physics & Astronomy Department California State University Northridge 18111 Nordhoff Street Northridge California 91330-8268 USA

High-contrast imaging provided by a coronagraph is critical for the direction imaging of the Earth-like planet orbiting its bright parent star.A major limitation for such direct imaging is the speckle noise that is induced from the wave-front error of an optical *** derive an algorithm for the wave-front measurement directly from 3.focal plane *** 3.images are achieved through a deformable mirror to provide specific phases for the optics *** introduce an extra amplitude modulation on one deformable mirror configuration to create an uncorrelated wave-front,which is a critical procedure for wave-front *** simulation shows that the reconstructed wave-front is consistent with the original wave-front theoretically,which indicates that such an algorithm is a promising technique for the wave-front measurement for the high-contrast imaging.

关键词： high-contrast imaging multi-image algorithm speckle nulling technique wave-front sensing

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RT Leonis Minoris:an Unstable W Ursae Majoris System with a Spotted Component

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chinese Journal of Astronomy and Astrophysics 2004年第6期4卷 553-562页

作者： Yu-Lan Yang and Qing-Yao Liunational astronomical observatories, Yunnan Observatory, {3. academy of Sciences,Kunming 650011 United Laboratory of Optical Astronomy, {3. academy of Sciences national astronomical observatories Yunnan Observatory Chinese Academy of Sciences Kunming 650011 []United Laboratory of Optical Astronomy Chinese Academy of Sciences

Complete BV light curves of the W UMa type binary RT LMi are presented. From the observations, four times of minimum light were determined. Based on the new times of minimum light and those collected from the literature, changes in the orbital period of the system were found and analyzed with Kalimeris et al.'s method. The result shows that the orbital period possibly oscillates with a cycle of about 64 years and an amplitude of 1.2 × 10-6 days. The present CCD photometric observations reveal that the light curves are obviously asymmetrical, and show a positive O'Connell effect, while the light curves obtained in 1982 exhibit a negative O'Connell effect. The present light curves were analyzed by means of the latest version of the Wilson-Devinney code, which was also used to correct the photometric effects, including the distortion on the radial-velocity curves obtained by Rucinski et al. The following absolute dimensions have been derived: MI -1.28 ±0.08 M⊙, M2 = 0.48 ±0.06 M⊙, R1 = 1.28 ±0.06 R⊙, R2 = 0.83.±0.05 R⊙, L1 = 1.88±0.12 L⊙, L2 = 0.77±0.08 L⊙, and A = 2.64±0.02 R⊙. The asymmetry of the light curves can be explained by a model with a cool spot on the secondary component. The orbital period modulation can be reproduced by a magnetic activity cycle model of the secondary component with ΔJ = 5.6 × 1046 g cm2 s-1, ΔΩ/Ω = 8.8 × 10-4, and B = 5.1 × 103.G.

关键词： star: contact binary - star: individuals: RT LMi - star: magnetic activity

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Possible triggering of solar activity to big earthquakes (Ms ≥ 8) in faults with near west-east strike in china

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Science china(Physics,Mechanics & Astronomy) 2004年第2期47卷 173-181页

作者： HAN Yanben1, GUO Zengjian1,2, WU Jinbing1,2 & MA Lihua1 1. national astronomical observatories, {3. academy of Sciences, Beijing 100012, china 2. Earthquake Research Institute of Lanzhou, CSB, Lanzhou 73.00, china Correspondence should be addressed to Han Yanben (email: hyb@***) 1. national astronomical observatories Chinese Academy of Sciences 100012 Beijing China 2. Earthquake Research Institute of Lanzhou CSB 73000 Lanzhou China

This paper studies the relationship between solar activity and big earthquakes (Ms≥8) that occurred in china and western Mongolia. It is discovered that the occurrence dates of most of the big earthquakes in and near faults with west-east strike are close to the maximum years of sunspot numbers, whereas dates of some big earthquakes which are not in such faults are not close to the maximum years. We consider that it is possibly because of the appearance of many magnetic storms in the maximum years of solar activity. The magnetic storms result in anomalies of geomagnetic field and then produce eddy current in the faults gestating earthquake with near west-east strike. Perhaps the gestated big earthquakes occur easily since the eddy current heats the rocks in the faults and therefore decreases the shear resistant intensity and the static friction limit of the rocks .

关键词： earthquake, solar activity, magnetic storm, eddy current.

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An Electron Density Model above the Sunspot from a Mapping of NOAA 7260 at 17 GHz

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chinese Journal of Astronomy and Astrophysics 2002年第3期2卷 287-292页

作者： Xing－FengYu Jin－XingYao nationalastronomicalobservatories ChineseAcademyofSciencesBeijing100012 PurpleMountainObservatory ChineseAcademyofSciencesNanjing210008

The brightness temperature distribution of microwave emission in a solar active region generally shows a ring structure, with a dip at the centre. However, no dip was found in the Nobeyama Radioheliograph left handed circular polarization (LCP) image on 1992 August 18; instead, there was a peak. This is a completely LCP source with zero right-handed circular polarization (RCP). We examine this structure in terms of the joint effect of gyroresonance and bremsstrahlung mechanism with a raised electron density above the central part of the sunspot, and the commonly assumed temperature and vertical dipole magnetic field models. The raised electron density is found to be 1.4 × 1011 cm-3.at the chromosphere base.

关键词： Sun: activity - sunspots - Sun: radio radiation - Sun: chromosphere

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An Alternative Explanation for a Screw-like Meteoric Train Photographed by Double-Station Observations

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chinese Journal of Astronomy and Astrophysics 2007年第6期7卷 814-822页

作者： Guang-Jie Wu1,2 1 national astronomical observatories/Yunnan Observatory,{3. academy of Sciences,Kunming 650011 2 Purple Mountain Observatory,{3. academy of Sciences,Nanjing 210008 Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008

Two-station observation of meteors, especially a meteor trains, provides an effective approach to the measurement of the physical parameters. We have collected four special groups of photographs of meteoric trains taken at two stations during Leonids 2001. One representative group has been measured and analyzed in detail. An analysis has been reported in our first paper. In this paper, an alternative explanation for the screw-like meteoric train is suggested based on some physical calculations. The results reveal that this train has a screw-like structure and, apparently, spoke beams. The mother meteor of this train may be negatively charged and moves forward along a left-hand screw trajectory under the effect of the geomagnetic field. The spoke beams might be the visual effect of the long time exposure of many particles released from the disintegrated meteoroid.

关键词： meteors meteoroids -- magnetic fields

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Positions and Spectral Energy Distributions of 41 Star Clusters in M3.

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chinese Journal of Astronomy and Astrophysics 2002年第3期2卷 197-206页

作者： Jun Ma, Xu Zhou, Jian-Sheng Chen, Hong Wu, Zhao-Ji Jiang, Sui-Jian Xue and Jin Zhunational astronomical observatories, {3. academy of Sciences, Beijing 100012 national astronomical observatories Chinese Academy of Sciences Beijing 100012

We present accurate positions and multi-color photometry for 41 star clusters detected by Melnick & D'odorico in the nearby spiral galaxy M3. as a part of the BATC Color Survey of the sky in 13.intermediate-band filters from 3.00 to 10 000 A. The coordinates of the clusters are found from the HST Guide Star Catalog. By aperture photometry, we obtain the spectral energy distributions of the clusters. Using the relations between the BATC intermediate-band system and UBVRI broadband system, we derive their V magnitudes and B - V colors and find that most of them are blue, which is consistent with previous findings.

关键词： galaxies: individual (M3.) - galaxies: evolution - galaxies: star clusters

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Magnetic and Velocity Fields in Flare Regions

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天文研究与技术 1999年第S1期 175-181页

作者： Li Wei 1(Beijing astronomical Observatory, The chinese academy of Sciences, Beijing {3.,china) 2(national astronomical observatories, The chinese academy of Sciences, Beijing {3., china)

This paper reviews observations of the solar magnetic and velocity fields in active regions where flares produce. Our study includes (1) the relationship among the magnetic fields, Doppler velocity fields and flares; (2) the relationship between magnetic shear and flares; (3. the relationship among electric currents, electric helicity and flares; (4) the evidence for non-potential magnetic field.

关键词： Magnetic and Velocity Fields in Flare Regions

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The relation between black hole masses and Lorentz factors of the jet components in blazars

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Research in Astronomy and Astrophysics 2009年第3期9卷 293-301页

作者： Ming Zhou1,2,3.and Xin-Wu Cao1,2 1 Shanghai astronomical Observatory, chinese academy of Sciences, Shanghai 20003., {3. 2 Joint Institute for Galaxy and Cosmology (JOINGC) of SHAO and USMC, Shanghai 20003., {3. 3.Graduate School of the chinese academy of Sciences, Beijing 100049, {3. Shanghai astronomical Observatory Chinese Academy of Sciences Shanghai 200030 China Joint Institute for Galaxy and Cosmology (JOINGC) of SHAO and USMC Shanghai 200030 China Graduate School of the chinese academy of Sciences Beijing 100049 China

We explore the relationship between black hole mass (MBH) and the motion of the jet components for a sample of blazars. The Very Long Baseline Array (VLBA) 2 cm Survey and its continuation: Monitoring of Jets in active galactic nuclei (AGNs) with VLBA Experiments (MOJAVE) have observed 278 radio-loud AGNs, of which 146 blazars have reliable measurements of their apparent velocities of the jet components. We calculate the minimal Lorentz factors for these sources from their measured apparent velocities, and their black hole masses are estimated with their broad-line widths. A sig- nificant intrinsic correlation is found between black hole masses and the minimal Lorentz factors of the jet components. The Eddington ratio is only weakly correlated with the min- imal Lorentz factor, which may imply that the Blandford-Znajek (BZ) mechanism may dominate over the Blandford-Payne (BP) mechanism for the jet acceleration (at least) in blazars.

关键词： black hole physics — galaxies: active — galaxies: jets — galaxies: nuclei

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Study of the primordial lithium abundance

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Science china(Physics,Mechanics & Astronomy) 2011年第S1期54卷 67-72页

作者： LI ZhiHong1, LI ErTao1, SU Jun1, LI YunJu1, BAI XiXiang1, GUO Bing1, WANG YouBao1, CHEN YongShou1, HOU SuQing1, ZENG Sheng1, LIAN Gang1, SHI JianRong2 & LIU WeiPing1 1 china Institute of Atomic Energy, Beijing 102413. china 2{3. astronomical observatories, chinese academy of Sciences, Beijing 100012, china china Inst Atom Energy Beijing 102413 Peoples R China chinese Acad Sci Natl Astron Observ Beijing 100012 Peoples R China

Lithium isotopes have attracted an intense interest because the abundance of both 6Li and 6Li from big bang nucleosynthesis (BBN) is one of the puzzles in nuclear astrophysics. Many investigations of both astrophysical observation and nucleosynthesis calculation have been carried out to solve the puzzle, but it is not solved yet. Several nuclear reactions involving lithium have been indirectly measured at china Institute of Atomic Energy, Beijing. The Standard BBN (SBBN) network calculations are then performed to investigate the primordial Lithium abundance. The result shows that these nuclear reactions have minimal effect on the SBBN abundances of 6Li and 7Li.

关键词： big bang nucleosynthesis element abundance nuclear reaction network

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Triaxial ellipsoid models of the Moon based on the laser altimetry data of Chang'E-1

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Science china Earth Sciences 2010年第11期53卷 1594-1601页

作者： WANG WenRui1,2,3. LI Fei1, LIU JianJun1, REN Xin2, ZOU XiaoDuan2,3. MU LingLi2, YAN JianGuo1, ZOU YongLiao2, ZHANG HongBo2, Lü Chang2, LIU JianZhong2, ZUO Wei2, SU Yan2, WEN WeiBin2, BIAN Wei2, WANG Min2, LI ChunLai2 & OUYANG ZiYuan2 1 School of Geodesy and Geomatics, Wuhan University, Wuhan 43.079, china 2 national astronomical Observatory of {3. academy of Sciences, Beijing 100012, china 3.Graduate School of {3. academy of Sciences, Beijing 100049, china 1. School of Geodesy and Geomatics Wuhan University Wuhan 430079 China2. National Astronomical Observatory of Chinese Academy of Sciences Beijing 100012 China3. Graduate School of Chinese Academy of Sciences Beijing 100049 China

Lunar geodetic parameters, which play an important role in lunar exploration, can be calculated from the gravity and topography data. With the CE-1 altimetry data and LP gravity model, we calculate such geodetic parameters as the principle moment of inertia, the principle inertia axes, equatorial radius, polar radius, mean radius, flattening and offset between center of mass and center of figure (DCOM-COF). According to the CE-1 altimetry data and the above geodetic parameters, a tri-axial ellipsoid (CE-1-LAM-GEO) and a tri-axial level ellipsoid (CE-1-LAM-LEVEL) are calculated individually, providing mass center and figure center offset (DCOM-COF) and parameters more reliable in direction and magnitude.

关键词： Chang’E-1 laser altimetry data lunar ellipsoid lunar gravity

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