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Spectroscopic study of globular clusters in the halo of M3. with the Xinglong 2.16 m telescope Ⅱ: dynamics, metallicity and age

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Research in Astronomy and Astrophysics 2012年第7期12卷 829-844页

作者： Zhou Fan Ya-Fang Huang Jin-Zeng li Xu Zhou Jun Ma yong-Heng Zhao Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academyof Sciences Beiiin~ 100012 China Graduate University of chinese academy of sciences Beijing 100049 China

In Paper I, we performed spectroscopic observations on 11 confirmed glob- ular clusters （GCs） in M3. with the Xinglong 2.16 m telescope. We mainly focused on the fitting method and the metallicity gradient for the M3. GC sample. Here, we analyze and further discuss the dynamics, metallicity and age, and their distributions, as well as the relationships between these parameters. In our work, eight more con- firmed GCs in the halo of M3. were observed, most of which lack previous spectro- scopic information. These star clusters are located far from the galactic center at a projected radius of ~ 14 to ~ 117 kpc, which is more spatially extended than that in the previous work. Firstly, we measured the lick absorption-line indices and the ra- dial velocities. Then the ages and metallicity values of [Fe/H] and [a/Fe] were fitted by comparing the observed spectral feature indices and the Single Stellar Population model of Thomas et al. in the Cassisi and Padova stellar evolutionary tracks, respec- tively. Our results show that most of the star clusters in our sample are older than 10 Gyr except B290, which is ~ 5.5 Gyr, and most of them are metal-poor with metallicity [Fe/H] 〈 - 1, suggesting that these clusters were born at the early stage of the galaxy＇s formation. We find that the metallicity gradient for the outer halo clusters with rp 〉 25 kpc may have an insignificant slope of -0.005 ＋ 0.005 dex kpc-1 and if the outliers G001 and H11 are excluded, the slope does not change significantly, with a value of -0.002 ~ 0.003.dex kpc-1. We also find that the metallicity is not a function of age for the GCs with age 〈 7 Gyr, but for the old GCs with age 〉 7 Gyr, there seems to be a trend that the older ones have lower metallicity. Additionally, we plot metallicity distributions with the largest sample of M3. GCs so far and show the bimodality is not significant, and the number of metal-poor and metal-rich groups be- comes comparable. The spatial distributions show that the me

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

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Short-Term Period Variation of Relative Sunspot Numbers

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chinese Journal of Astronomy and Astrophysics 2007年第6期7卷 823-830页

作者： Zhi-Qiang Yin Yan-Ben Han li-Hua Ma Gui-Ming Le yong-Gang Han national astronomical observatories Chinese Academy of Sciences Beijing 100012 Key Laboratory of Radiometric Calibration and Validation for Environmental Satellites China Meteorological Administration Beijing 100081 Graduate School of chinese academy of sciences Beijing 100049

We use wavelet transform to analyze the daily relative sunspot number series over solar cycles 10-23. The characteristics of some of the periods shorter than - 600-day are discussed. The results exhibit not only the variation of some short periods in the 14 solar cycles but also the characteristics and differences around solar peaks and valley years. The short periodic components with larger amplitude such as ～27, ～ 150 and ～3.0-day are obvious in some solar cycles, all of them are time-variable, also their lengths and amplitudes are variable and intermittent in time. The variable characteristics of the periods are rather different in different solar cycles.

关键词： Sun sunspots short-term period -- methods data analysis -- wavelet

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Einstein Probe discovery of EP240408a:A peculiar X-ray transient with an intermediate timescale

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Science China(Physics,Mechanics & Astronomy) 2024年

作者： Wenda Zhang Weimin Yuan Zhixing ling yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati lixin Dai Jingwei Hu Shumei Jia Chichuan Jin Dongyue li Paul O’Brien Rongfeng Shen Xinwen Shu Shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P. U. Fynbo Lluis Galbany Saurabh W. Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong li Bifang liu Mingjun liu Xing liu Yuan liu Zhu liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge Jin Chengkui li Junfei li Longhui li Maoshun li Wei li Zhengda li Tianying lian Congzhan liu Heyang liu Huaqiu liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu Pan Xin Pan liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck Institute for Extraterrestrial Physics Innovation academy for Microsatellites chinese academy of sciences Department of Physics University of Hong Kong School of Physics and Astronomy University of Leicester School of Physics and Astronomy Sun Yat-sen University national astronomical observatories Department of Physics Anhui Normal University Shanghai Institute of Technical Physics chinese academy of sciences Physics Department Tsinghua University Nevada Center for Astrophysics University of Nevada Las Vegas Department of Physics and Astronomy University of Nevada Las Vegas chinese academy of sciences South African astronomical Observatory Department of Astronomy University of Cape Town Department of Physics University of the Free State Universite' Paris Cite' CNRS Astroparticule et Cosmologie Universite' Paris Cite' CEA Paris-Saclay School of Astronomy and Space sciences IRFU/DAp-AIM Department of Astronomy Guangzhou University Cosmic Dawn Center (DAWN) Niels Bohr Institute University of Copenhagen Department of Physics and Astronomy Rutgers the State University of New Jersey Institute for Cosmic Ray Research University of chinese academy of sciences The University of Tokyo ESA/ESTEC Noordwijk 2201 AZ The Netherlands Department of Astronomy School of Physics Huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney Institute for Astronomy School of Physics Key Laboratory of Particle Astrophysics The University of Sydney Department of Astronomy Xiamen University Institute for Frontiers in Astronomy and Astrophysics beijing Normal University Department of Astronomy University of Science and Technology Hefei School of Astronomy and Space sciences University of Science and Technology of China Institute of High Energy Physics Institute of Deep Space sciences Deep Space Exploration Laboratory Department of Astronomy School of Physics and Astronomy Yunnan University Shanghai astronomical Observatory chinese academy of Science

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 keV,3.0 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 keV,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for4d,followed by a steep decay till becoming undetectable10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23.d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

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Computation of the atmosphere-less light intensity curve during a total solar eclipse by using Lunar Reconnaissance Orbiter topography data and the DE43. astronomical ephemeris

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Research in Astronomy and Astrophysics 2021年第1期21卷 105-118页

作者： Yun-Bo Wang Jian-Guo Yan Mao Ye yong-Zhang Yang Fei li Jean-Pierre Barriot State Key Laboratory of InformationEngineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China Geodesy Observatory of Tahiti University of French PolynesiaBP 657098702 FaaTahitiFrench Polynesia Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

Observations of the sky irradiation intensity in the visible wavelengths during a solar eclipse permit to model the Sun diameter,a key number to constrain the internal structure of our *** this paper,we present an algorithm that takes advantage of the precise Moon topography from Lunar Reconnaissance Orbiter to compute,with a high resolution in time,the geometrical part(***-of-atmosphere,and for a given wavelength)of the sky irradiation at any given location on the Earth during these *** algorithm is also able to model the Baily’s *** give as an application the theoretical computation of the light curve corresponding to the solar eclipse observed at Lakeland(Queensland,North Australia)on 2012 November *** application to real data,with the introduction of atmospheric and instrumental passbands,will be considered in a forthcoming paper.

关键词： eclipse Moon Sun:fundamental parameters

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New supernova candidates from the SDSS-DR7 spectral survey

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Research in Astronomy and Astrophysics 2009年第6期9卷 635-640页

作者： liang-Ping Tu A-li Luo Fu-Chao Wu Chao Wu yong-Heng Zhao Institute of Automation Chinese Academy of Sciences Beijing 100190 China national astronomical observatories Chinese Academy of Sciences Beijing 100012 China School of Science University of Science and Technology Liaoning Anshan 114051 China

This letter presents 25 supernova candidates discovered from SDSS-DR7 by using our dedicated method, called Sample Decrease. Ten of them have been confirmed by other research groups, while the remaining 15, including 14 Type la and one Type Ⅱ, are first discovered based on Supernova Identification analysis. The results demonstrate that our method is reliable. The description of the method and some detailed spectral analysis procedures are also presented.

关键词： techniques spectroscopic -- supernovae method -- data analysis

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Focal surface attitude detection for LAMOST

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Research in Astronomy and Astrophysics 2020年第11期20卷 263-272页

作者： Tian-Zhu Hu yong Zhang Xiang-Qun Cui Ye-Ping li Xiu-Shan Pan Ying Fu national astronomical observatories/Nanjing Institute of astronomical Optics&Technology Chinese Academy of ScienceNanjing 210042China CAS Key Laboratory of astronomical Optics&Technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China University of chinese academy of sciences Beijing 100049China

With telescope apertures becoming larger and larger,the deployment of large-field telescopes is becoming increasingly ***,optical path calibration is necessary to ensure the image quality of large-field and large-diameter *** particular,focal plane attitude calibration is an essential optical path calibration technique that has a direct impact on image *** this paper,a focal plane attitude detection method using eight acquisition cameras is proposed based on the calibration requirements of the wide-field telescope,LAMOST(Large Sky Area Multi-Object Fiber Spectroscopic Telescope).Comparison of simulation and experimental results shows that the detection accuracy of the proposed method can reach 3. *** additional testing and verification,this method could be used to facilitate regular focal plane attitude calibration for LAMOST as well as other large-field telescopes.

关键词： methods data analysis techniques high angular resolution techniques image processing

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A study on universal observation control system and its application for LAMOST

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Research in Astronomy and Astrophysics 2021年第6期21卷 369-386页

作者： Zheng Wang Yuan Tian Jian li Zi-Huang Cao yong-Heng Zhao Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of chinese academy of sciences Beijing 100049China

The observatory control system(OCS),a part of automated control of Large Sky Area MultiObject Fibre Spectroscopic Telescope(LAMOST),runs on the CentOS6 platform and implements the communication between modules based on Common Object Request Broker Architecture(CORBA).However,CORBA is complicated and has limited development support;moreover,the official support for CentOS6 has *** inherently has some shortcomings such as the over-concentration of control and the blocking of device status processing,which hinder the realization of automated observation control of ***,this study designs and implements a universal observation control system(UOCS)for optical *** UOCS takes the device command as the basic execution unit,controls the device execution logic using observation script,controls the observation logic by event-driven messaging,and realizes mutual decoupling between modules via a distributed control mode,thereby ensuring high system *** UOCS performs significantly better than OCS in terms of the observation performance,operator complexity,and communication ***,UOCS is applied to the automated control of some devices and subsystems in LAMOST *** will be applied to the automated observation control of Multi-channel Photometric Survey Telescope by 2021.

关键词： telescopes techniques:miscellaneous methods:observational instrumentation:miscellaneous

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M1 transition energy and rate in the ground configuration of Ag-like ions with 62 ≤ Z ≤ 94

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chinese Physics B 2022年第1期31卷 221-226页

作者： Ju Meng Wen-Xian li Ji-Guang li Ze-Qing Wu Jun Yan yong Wu Jian-Guo Wang national Key Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Key Laboratory of Solar Activity National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100012China HEDPS Center for Applied Physics and Technologyand College of EngineeringPeking UniversityBeijing 100871China

Systematic calculations and assessments are performed for the magnetic dipole(M1)transition energies and rates between the ^(2)F^(o)_(5/2,7/2) levels in the ground configuration 4d104f along the Ag-like isoelectronic sequence with 62≤Z≤94 based on the second-order many-body perturbation theory implemented in the Flexible Atomic *** electron correlations,Breit interaction and quantum electrodynamics effects are taken into account in the present *** accuracy and reliability of our results are evaluated through comprehensive comparisons with available measurements and other theoretical *** transition energies,our results are in good agreement with the recent experimental data obtained from the electron beam ion traps within 0.18%.The maximum discrepancy between our results and those obtained with the large-scale multiconfiguration Dirac–Hartee–Fock calculations by Grumer et al.[***.A 89062501(2014)]is less than 0.13.along the isoelectronic ***,the corresponding M1 transition rates are also *** present results can be used as the benchmark and useful for spectra simulation and diagnostics of astrophysical and fusion plasmas.

关键词： Ag-like ions magnetic dipole transition fine-structure splitting

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GeneticKNN:a weighted KNN approach supported by genetic algorithm for photometric redshift estimation of quasars

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Research in Astronomy and Astrophysics 2021年第1期21卷 165-177页

作者： Bo Han li-Na Qiao Jing-lin Chen Xian-Da Zhang Yan-Xia Zhang yong-Heng Zhao School of Computer Science Wuhan UniversityWuhan 430072China Institute of Electronics Chinese Academy of SciencesBeijing 100190China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

We combine K-nearest neighbors(KNN)with a genetic algorithm(GA)for photometric redshift estimation of quasars,short for GeneticKNN,which is a weighted KNN approach supported by a *** approach has two improvements compared to KNN:one is the feature weighted by GA;the other is that the predicted redshift is not the redshift average of K neighbors but the weighted average of median and mean of redshifts for K neighbors,i.e.p×zmedian+(1-p)×*** on the SDSS and SDSS-WISE quasar samples,we explore the performance of GeneticKNN for photometric redshift estimation,comparing with the other six traditional machine learning methods,*** least absolute shrinkage and selection operator(LASSO),support vector regression(SVR),multi-layer perceptrons(MLP),XGBoost,KNN and random *** and random forest show their *** the easy implementation of KNN,we make improvement on KNN as GeneticKNN and apply GeneticKNN on photometric redshift estimation of *** the performance of GeneticKNN is better than that of LASSO,SVR,MLP,XGBoost,KNN and random forest for all *** the accuracy is better with the additional WISE magnitudes for the same method.

关键词： astronomical databases:catalogs (galaxies:)quasars:general methods:statistical techniques:miscellaneous

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Feedback of Active Galactic Nuclei in Seyfert 2 Galaxies

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chinese Journal of Astronomy and Astrophysics 2008年第5期8卷 537-546页

作者： En-Peng Zhang Wei-Hao Bian Chen Hu Wei-Ming Mao A-li Luo yong-Heng Zhao national astronomical Observatory Chinese Academy of Sciences Beijing 100012 China Department of Physics and Institute of Theoretical Physics Nanjing Normal University Nanjing 210097 China Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China

It is well accepted that feedback from active galactic nuclei （AGNs） plays an important role in the coevolution of the supermassive black hole （SMBH） and its host galaxy, but the concrete mechanism of feedback remains unclear. A considerable body of evidence suggests that AGN feedback suppresses star formation in the host galaxy. We assemble a sample of Seyfert 2 galaxies with recent observational data of compact nuclear starbursts and estimate the gas surface density as a function of column density to illuminate the relation between feedback and AGN properties. Although there are some uncertainties, our data still imply the deviation from the star formation law （Kennicutt-Schmidt law）. Further, they indicate that：（1） Feedback correlates with the Eddington ratio, rather than with the mass of SMBH, as a result of decreasing star formation efficiency. （2） The SMBH and the torus are probably undergoing coevolution. Conclusions presented here can be refined through future high resolution CO or HCN observations.

关键词： galaxies active - galaxies Seyfert- feedback

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