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The tidal tails of globular cluster Palomar 5 based on the neural networks method

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Research in Astronomy and Astrophysics 2009年第10期9卷 1131-1148页

作者： hu zou Zhen-Yu Wu Jun Ma Xu Zhou National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The sixth Data Release （DR6） of the Sloan Digital Sky Survey （SDSS） provides more photometric regions, new features and more accurate data around globular cluster Palomar 5. A new method, Back Propagation Neural Network （BPNN）, is used to estimate the cluster membership probability in order to detect its tidal tails. Cluster and field stars, used for training the networks, are extracted over a 40 × 20 deg^2 field by color-magnitude diagrams （CMDs）. The best BPNNs with two hidden layers and a Levenberg-Marquardt （LM） training algorithm are determined by the chosen cluster and field samples. The membership probabilities of stars in the whole field are obtained with the BPNNs, and contour maps of the probability distribution show that a tail extends .5.42° to the north of the cluster and another tail extends 3.77° to the south. The tails are similar to those detected by Odenkirchen et al., but no more debris from the cluster is found to the northeast in the sky. The radial density profiles are investigated both along the tails and near the cluster center. Quite a few substructures are discovered in the tails. The number density profile of the cluster is fitted with the King model and the tidal radius is determined as 14.28＇. However, the King model cannot fit the observed profile at the outer regions （R 〉 8＇） because of the tidal tails generated by the tidal force. Luminosity functions of the cluster and the tidal tails are calculated, which confirm that the tails originate from Palomar 5.

关键词： methods statistical -- galaxy halo -- galaxy structure -- globular cluster individual (Palomar 5)

Epilepsy: Quality of life and assessment scale evaluation

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Neural Regeneration Research 2008年第1期3卷 83-88页

作者： Fayun hu Xiaoyi zou Department of Neurology West China Hospital Sichuan University Chengdu 610041 Sichuan Province China

BACKGROUND： Quality of life （QOL） is an important topic in current international research of epilepsy. In countries other than China, QOL in epilepsy has been well studied, and many assessment scales or QOL of epilepsy have been developed and used in the clinical practice. In China, concern for QOL of epilepsy patients is very recent, and QOL assessment scales, which correspond to China＇s basic conditions, are still needed. OBJECTIVE： This review aimed to analyze the primary influencing factors and assessment scales of QOL in epilepsy, to investigate the topics of current and future research for QOL of epilepsy patients, and to highlight the importance of QOL for epilepsy patients, according to China＇s basic conditions. RETRIEVAL STRATEGY： Using the terms ＂quality of life in epilepsy＂, we computer-retrieved from the PubMed （http：//***/PubMed） database human studies published between January 1998 and April 2007 in the English language. A total of 745 manuscripts were searched, of which 243 were review papers. At the same time, we computer-searched the China National Knowledge Infrastructure with the terms ＂epilepsy and quality and life＂ in the Chinese language for studies published between 2002 and 2007. Altogether, 181 Chinese literatures were retrieved, 32 of which were from high-impact journals. LITERATURE EVALUATION： The retrieved manuscripts were initially selected, but 50 were kept for further analysis. The selected manuscripts were as follows： 31 Chinese and/or English studies addressed the influencing factors of QOL for epilepsy patients, as well as assessment scales for QOL in different populations of epilepsy patients, of which 5 were review articles and the remaining 26 were clinical studies; and 19 Chinese and/or English literatures were rejected, because they were not in accordance with the inclusive criteria. DATA SYNTHESIS： QOL for epilepsy patients is an emerging field. At present, ＂the Liverpool group model for determining QOL in peo

关键词： epilepsy quality of life China.

Spatially-resolved stellar population properties of the M51–NGC 5195 system from multi-wavelength photometric data

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Research in Astronomy and Astrophysics 2021年第1期21卷 53-66页

作者： Peng Wei hu zou Lin Lin Xu Zhou Xiang Liu Xu Kong Lu Ma Shu-Guo Ma Kinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 101408China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing100012China Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Key Laboratory for Research in Galaxies and Cosmology Department of Astronomy.University of Science and Technology of ChinaHefei 230026China

Using multi-band photometric images of M51 and its companion NGC 5195 from ultraviolet to optical and infrared,we investigate spatially resolved stellar population properties of this interacting system with stellar population synthesis *** observed infrared excess(IRX)is used to constrain dust *** mass is also inferred from the model *** fitting observed spectral energy distributions(SEDs)with synthetical ones,we derive two-dimensional distributions of stellar age,metallicity,dust extinction and stellar *** M51,two grand-designed spiral arms extending from the bulge show young age,rich metallicity and abundant *** inter-arm regions are filled with older,metalpoorer and less dusty stellar *** for the spiral arm extending from M51 into NGC 5195,the stellar population properties of NGC 5195 are quite *** 5195 is much older than M51,and its core is very dusty with AV up to 1.67 mag and dense in stellar mass surface *** close encounters might drive the dust in the spiral arm of M51 into the center of NGC 5195.

关键词： galaxies:evolution galaxies:individual(M51) galaxies:photometry

The correction of diurnal effects on CSTAR photometry

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Research in Astronomy and Astrophysics 2014年第3期14卷 345-356页

作者： Song-hu Wang Xu Zhou hui Zhang Ji-Lin Zhou hui-Gen Liu Ze-Yang Meng Jun Ma Tian-Meng Zhang Zhou Fan hu zou Department of Astronomy & Key Laboratory of Modern Astronomy and Astrophysics in Ministry of Education Nanjing University National Astronomical Observatories Chinese Academy of Sciences

In January, 2008 the Chinese Small Telescope ARray （CSTAR） was suc-cessfully deployed at Dome A, Antarctica. Because CSTAR consists of four static14.5 cm telescopes pointing at the same 4.5° x 4.5° field around the south celestialpole, diurnal motion can be seen in its field of view. The stars are centered at differentpositions in different exposure frames. During four months of continuous observationsduring the polar night of 2008, about 0.3 million/-band images were obtained. In thelatest version of the released photometric catalog, the effects of diurnal motion of thestars on the static CSTAR optical system can be obviously found. In this work, weupdate the CSTAR catalog by carefully analyzing and correcting the systematic errorscaused by diurnal motion of stars on imperfectly flat-fielded frames.

关键词： methods: data analysis techniques: photometric

Comparison between toric and spherical phakic intraocular lenses combined with astigmatic keratotomy for high myopic astigmatism

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Eye and Vision 2017年第1期4卷 114-120页

作者： Lin-Yan Zheng Shuang-Qian Zhu Yan-Feng Su hu-Yong zou Qin-Mei Wang A-Yong Yu The Eye Hospital of Wenzhou Medical University 270 Xueyuan West RoadWenzhou 325000ZhejiangPeople’s Republic of China

Background:To compare the outcomes of a toric phakic intraocular lens(PIOL)and a spherical PIOL combined with astigmatic keratotomy(AK)for the correction of high myopic ***:This study enrolled patients with high myopic astigmatism,including 30 eyes(22 patients)that received a toric PIOL implantation(TICL group),and 32 eyes(24 patients)that received combined AK and a spherical PIOL implantation(AK+ICL group).The outcomes were compared between the two groups before surgery,and at the following time points after surgery:1 week,1,3,6 months,and 1,2 ***:Preoperatively,the mean manifest spherical equivalent(SE)was−14.14±2.12 D in the TICL group and−14.83±2.79 D in the AK+ICL group(P=0.28),and the mean manifest refractive cylinder,−2.87±1.09 D and−2.58±0.85 D,respectively(P=0.28).Two years postoperatively,the mean safety index was 1.53±0.55 in the TICL group and 1.60±0.70 in the AK+ICL group(P=1.00),and the mean efficacy index,1.18±0.45 and 1.38±0.52,respectively(P=0.86).The mean manifest refractive cylinder correction was 1.94±1.07 D in the TICL group and 1.39±0.71 D in the AK+ICL group(P=0.02).The mean changes in SE and refractive cylinder from 1 week to 2 years were less than 0.50 D in both ***:Both TICL implantation and AK+ICL implantation are a good alternative for correction of astigmatism in addition to high *** implantation has better predictability in correction of high myopic astigmatism.

关键词： Astigmatism High myopia Phakic intraocular lenses Astigmatic keratotomy

Photometric Redshifts and Galaxy Clusters for DES DR2, DESI DR9, and HSC-SSP PDR3 Data

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Research in Astronomy and Astrophysics 2022年第6期22卷 1-21页

作者： hu zou Jipeng Sui Suijian Xue Xu Zhou Jun Ma Zhimin Zhou Jundan Nie Tianmeng Zhang Lu Feng Zhixia Shen Jiali Wang Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Science University of Chinese Academy of SciencesBeijing 101408China

Photometric redshift(photoz)is a fundamental parameter for multi-wavelength photometric surveys,while galaxy clusters are important cosmological probes and ideal objects for exploring the dense environmental impact on galaxy *** extend our previous work on estimating photoz and detecting galaxy clusters to the latest data releases of the Dark Energy Spectroscopic Instrument(DESI)imaging surveys,Dark Energy Survey(DES)and Hyper Suprime-Cam Subaru Strategic Program(HSC-SSP)imaging surveys and make corresponding catalogs publicly available for more extensive scientific *** photoz catalogs include accurate measurements of photoz and stellar mass for about 320,293and 134 million galaxies with r<23,i<24 and i<25 in DESI DR9,DES DR2 and HSC-SSP PDR3 data,*** photoz accuracy is about 0.017,0.024 and 0.029 and the general redshift coverage is z<1,z<1.2 and z<1.6,respectively for those three *** uncertainty of the logarithmic stellar mass that is inferred from stellar population synthesis fitting is about 0.2 *** the above photoz catalogs,galaxy clusters are detected using a fast cluster-finding algorithm.A total of 532,810,86,963 and 36,566 galaxy clusters with the number of members larger than 10 is discovered for DESI,DES and HSC-SSP,*** photoz accuracy is at the level of *** total mass of our clusters is also estimated by using the calibration relations between the optical richness and the mass measurement from X-ray and radio *** photoz and cluster catalogs are available at Science DB(https://***/10.11922/sciencedb.o00069.00003)and Paper Data Repository(https://***/10.12149/101089).

关键词： galaxies clusters general-galaxies distances and redshifts-galaxies photometry

Kinematics and stellar population properties of the Andromeda galaxy by using the spectroscopic observations of the Guoshoujing Telescope

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Research in Astronomy and Astrophysics 2011年第9期11卷 1093-1110页

作者： hu zou Yan-Bin Yang Tian-Meng Zhang Jun Ma Xu Zhou Ali Luo Hao-Tong Zhang Zhong-Rui Bai Yong-Heng Zhao National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The Andromeda galaxy was observed by the Guoshoujing Telescope （formerly named the Large Sky Area Multi-Object Fiber Spectroscopic Telescope -- LAMOST）, during the 2009 commissioning phase. Due to the absence of standard stars for flux calibration, we use the photometric data of 15 intermediate bands in the Beijing-Arizona-Taipei-Connecticut （BATC） survey to calibrate the spectra. In to- tal, 59 spectra located in the bulge and disk of the galaxy are obtained. Kinematic and stellar population properties of the stellar content are derived with these spectra. We obtain the global velocity field and calculate corresponding rotation velocities out to about 7 kpc along the major axis. These rotation velocity measurements comple- ment those of the gas content, such as the H I and CO. The radial velocity dispersion shows that the stars in the bulge are more dynamically thermal and the disk is more rotationally-supported. The age distribution shows that the bulge was formed about 12 Gyr ago, the disk is relatively younger and the ages of some regions along the spi- ral arms can reach as young as about 1 Gyr. These young stellar populations have a relatively richer abundance and larger reddening. The overall average metallicity of the galaxy approximates the solar metallicity and a very weak abundance gradient is gained. The reddening map gives a picture of a dust-free bulge and a distinct dusty ring in the disk.

关键词： methods: data analysis -- techniques: spectroscopic -- galaxies: indi- vidual (M31) -- galaxies: stellar content

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

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 222-240页

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 National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and Space Sciences University of Chinese Academy of Sciences Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Institute of Space Sciences (ICE) CSIC 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 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 South African Astronomical Observatory Department of Astronomy University of Cape Town Department of Physics University of the Free State Université Paris Cité CNRS Astroparticule et Cosmologie Université Paris Cité CEA Paris-Saclay 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 The University of Tokyo ESA/ESTEC Department of Astronomy School of Physics huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney Institute for Astronomy School of Physics 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 School of Astronomy and Space Sciences University of Science and Technology of China Institute of Deep Space Sciences Deep Space Exploration Laboratory Department of Astronomy School of Physics and Astronomy Yunnan University Shanghai Astronomical Observatory Chi

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 ke V,～300 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 ke V,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for ～4 d,followed by a steep decay till becoming undetectable ～10 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 of～10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients ${\bm~{Einstein~~Probe}}$

Multicolor photometry of the nearby galaxy cluster A119

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Research in Astronomy and Astrophysics 2012年第10期12卷 1381-1401页

作者： Jin-Tao Tian Qi-Rong Yuan Xu Zhou Zhao-Ji Jiang Jun Ma Jiang-hua Wu Zhen-Yu Wu Tian-Meng Zhang hu zou National Astronomical Observatories Chinese Academy of Sciences Beiiing 100012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Optical Astronomy National Astronomical Observatories Chinese Academyof Sciences Beijing 100012 China Department of Physics Nanjing Normal University Nanjing 210046 China Department of Astronomy Beijing Normal University Beijing 100875 China

This paper presents multicolor optical photometry of the nearby galaxy cluster Abell 119 （z = 0.0442） with the Beijing-Arizona-Taiwan-Connecticut system of 15 intermediate bands. Within the BATC field of view of 58＇× 58＇, there are 368 galaxies with known spectroscopic redshifts, including 238 member galaxies （called sample I）. Based on the spectral energy distributions of 1376 galaxies brighter than iBATC ---- 19.5, the photometric redshift technique and the color-magnitude relation of early-type galaxies are applied to select faint member galaxies. As a result, 117 faint galaxies were selected as new member galaxies. Combined with sample I, an enlarged sample （called sample II） of 355 member galaxies is obtained. Spatial distribution and localized velocity structure for two samples demonstrate that A119 is a dynami- cally complex cluster with at least three prominent substructures in the central region within 1 Mpc. A large velocity dispersion for the central clump indicates a merging along the line of sight. No significant evidence for morphology or luminosity segrega- tions is found in either sample. With the PEGASE evolutionary synthesis model, the environmental effect on the properties of star formation is confirmed. Faint galaxies in the low-density region tend to have longer time scales of star formation, smaller mean stellar ages, and lower metallicities in their interstellar medium, which is in agreement with the context of the hierarchical cosmological scenario.

关键词： galaxies: clusters: individual (A119)- galaxies: distances and redshifts-- galaxies: evolution-- galaxies: kinematics and dynamics-- methods: data analysis