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2.ASS photometry and age estimation of the globular clusters in the outer halo of M31

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Research in astronomy and Astrophysics 2012年第2期12卷 115-126页

作者： Jun Ma 1,2. National Astronomical Observatories,chinese academy of {2.,Beijing 100012.china 2.Key laboratory of optical astronomy,National Astronomical Observatories,chinese academy of {2.,Beijing 100012.china National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Key laboratory of optical {2. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We present the first photometric results in J, H and Ks from 2.ASS （Two Micron All Sky Survey） imaging of 10 classical globular clusters （GCs） in the far outer regions of M31. Combined with the V and I photometric data from previous literature, we constructed a color-color diagram between J - Ks and V - Ⅰ. By comparing the integrated photometric measurements with evolutionary models, we estimate the ages of these clusters. The results showed that all of these clusters are older than 3 × 109 yr, and among them four are older than 10 Gyr and the other six have intermediate ages between 3 - 8 Gyr. The masses for these outer-halo GCs are from 7.0 × 104 M to 1.02.× 10^6 M. We argued that GC2.and GC3, whose ages, metallicities and distance moduli are almost the same, were accreted from the same satellite galaxy, if they did not form in situ. The statistical results show that the ages and metallicities of these 10 M31 outer-halo GCs do not vary with projected radial position, and a relationship between age and metallicity does not exist.

关键词： galaxies: halos - galaxies: individual (M31) - star clusters: general

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, chinese academy of sciences,Kunming 650011 United laboratory of {2. astronomy, chinese 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 -1.2. ±0.08 M⊙, M2.= 0.48 ±0.06 M⊙, R1 = 1.2. ±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

Narrow line Seyfert 1 galaxies: where are the broad line regions?

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Science china(Physics,Mechanics & astronomy) 2010年第12期53卷 2307-2311,2339-2343页

作者： MAO WeiMing 1,2.3 , HU Chen 2., WANG JianMin 2., BIAN WeiHao 4 , ZHANG Shu 2.& ZHAO Gang 1 1 Key laboratory of optical {2., National Astronomical Observatories, chinese academy of sciences, Beijing 100012. china 2.Key laboratory for Particle Astrophysics, Institute of High Energy Physics, chinese academy of sciences, Beijing 100049, china 3 Graduate University of the chinese academy of sciences, Beijing 100049, china 4 Department of Physics, nanjing Normal University, nanjing 2.0011, china 1. Key laboratory of optical {2. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China2. Key Laboratory for Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China3. Graduate University of the Chinese Academy of Sciences Beijing 100049 China4. Department of Physics Nanjing Normal University Nanjing 210011 China

A sample consisting of 2.1 narrow line Seyfert 1 galaxies (NLS1s) with high quality spectra from the Sloan Digital Sky Survey (SDSS) is selected to explore where broad line regions are in these objects. We find that the Hβ profile can be fitted well by three (narrow, intermediate and broad) Gaussian components, and the FWHM ratios of the broad to the intermediate components hold a constant of 3.0 roughly for the entire sample. If the broad components originate from the region scaled by the well-determined Hβ reverberation mapping relation, we find that the intermediate components originate from the inner edge of the torus, which is scaled by dust K-band reverberation. We find that the IC and the BC are strongly linked dynamically, but the relation of their covering factors is much more relaxed, implying that both regions are clumpy.

关键词： black hole physics galaxies: evolution quasars: general

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,{2., Beijing 100012.United laboratory of optical astronomy{2. 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

Identification of ten new Galactic HII regions

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Science china(Physics,Mechanics & astronomy) 2010年第6期53卷 1144-1152页

作者： RUAN GuiPing 1,2.& SHI WeiBin 1,2.1 Shandong Provincial Key laboratory of optical {2. and Solar-Terrestrial Environment,School of Space Science and Physics,Shandong University at Weihai,Weihai 2.42.9,china 2.Key laboratory of optical {2.,National Astronomical Observatories,chinese academy of sciences,Beijing 100012.china 1. Shandong Provincial Key laboratory of optical {2. and Solar-Terrestrial Environment School of Space Science and Physics Shandong University at Weihai Weihai 264209 China2. Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

We discovered ten large HII regions in the Sino-German λ6 cm polarization survey of the Galactic plane. They have been identified according to their flat spectral indexes and the high ratio between the 60 μm infrared emission and the λ6 cm emission. The integrated flux densities as well as the sizes of these sources are given at 4800 MHz. Cross-identifications are made with other major radio catalogs.

关键词： radio continuum general-methods observational-HII regions

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 {2.,Beijing 100012.china 2.Key laboratory of optical astronomy,National Astronomical Observatories,chinese academy of {2.,Beijing 100012.china National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Key laboratory of optical {2. 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 0.02. ± 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 > 2. 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

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

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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 {2. of sciences,nanjing 2.0042.china 2.Key laboratory of Astronomical Optics & Technology,nanjing Institute of Astronomical Optics & Technology,chinese {2. of sciences,nanjing 2.0042.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 91330-82.8,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

Wet-chemical synthesis and characteristics of Au nanoshell

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Science china Chemistry 2005年第5期48卷 431-435页

作者： LIU Zhongxin1,2. SONG Hongwei1, YU Lixin1,2. YANG Linmei1,2.& PAN Guohui1,2.1. Key laboratory of Excited State Physics, Changchun Institute of Optics, Fine Mechanics and Physics, chinese academy of sciences, Changchun 130033,{2. 2. Graduate School of the chinese academy of sciences, Beijing 100039,{2. 1. Key laboratory of Excited State Physics Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences 130033 Changchun China 2. Graduate School of the chinese academy of sciences 100039 Beijing China

Gold nanoshells were prepared by an easy wet-chemical method, with Ag nanoparticles used as the templates. Transmission electron microscopy (TEM) indicated that the shells were sphere in shape, the size was homogenous, being about 2. nm, and no hard ag-glomerates were observed. The plasma resonance absorption of gold was tuned from visible to near-infrared (NIR) with the increased volume of HAuCl4. The temperature grads (?T) of the gold nanoshell hydrosol under the exposure of an 808-nm optical fiber laser with different power den-sities were measured. The highest ?T was 30℃ (5 W/cm2. irradiation area was 2.cm2.. This kind of gold nanoshell hydrosol is a promising material to be used in biomedicine such as photo-thermal cancer therapy, and its special photothermal convert property will photothermally trigger drug release.

关键词： wet-chemical synthesis, Au, nanoshell, NIR absorption, photothermal conversion.

An iterative wavefront sensing algorithm for high-contrast imaging systems

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Research in astronomy and Astrophysics 2011年第2期11卷 198-204页

作者： Jiang-Pei Dou 1,2.De-Qing Ren 1,2.3 and Yong-Tian Zhu 1,2.1 National Astronomical Observatories/nanjing Institute of Astronomical Optics & Technology,chinese {2. of sciences,nanjing 2.0042.china 2.Key laboratory of Astronomical Optics & Technology,nanjing Institute of Astronomical Optics & Technology,chinese {2. of sciences,nanjing 2.0042.china 3 Physics & astronomy Department,California State University Northridge,18111 Nordhoff Street,Northridge,California 91330-82.8,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 Physics & astronomy Department California State University Northridge 18111 Nordhoff Street Northridge California 91330-8268 USA

Wavefront sensing from multiple focal plane images is a promising technique for high-contrast imaging ***,the wavefront error of an optics system can be properly reconstructed only when it is very *** paper presents an iterative optimization algorithm for the direct measurement of large static wavefront errors from only one focal plane *** first measure the intensity of the pupil image to get the pupil function of the system and acquire the aberrated image on the focal plane with a phase error that will be *** we induce a dynamic phase on the tested pupil function and calculate the associated intensity of the reconstructed image on the focal *** algorithm will then try to minimize the intensity difference between the reconstructed image and the aberrated test image in the focal plane,where the induced phase is a variable of the optimization *** simulation shows that the wavefront of an optical system can theoretically be reconstructed with high precision,which indicates that such an iterative algorithm may be an effective way to perform wavefront sensing for high-contrast imaging systems.

关键词： techniques: image processing -- methods: numerical -- planetarysystems