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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 {2. observatories, yunnan observatory, chinese academy of Sciences,kunming 650011 United Laboratory of Optical Astronomy, chinese academy of Sciences national astronomical {2. Yunnan Observatory Chinese Academy of Sciences Kunming 650011

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

Three-dimensional Distribution of the Escape Photons of Hα Flares

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chinese Journal of Astronomy and Astrophysics 2006年第1期6卷 87-95页

作者： Ming-Guo Sun Zhong-Quan Qu Zhi Xu Xiao-yu Zhang Cheng-Lin XU Shuai Wang Chun-Lan Jin yunnan astronomical {2./national astronomical observatories Chinese Academy ofn Sciences Kunming 650011 Department of Astronomy Nanjing University Nanjing 210093 Graduate University of the chinese academy of Sciences Beijing 100049

A technique for obtaining a three-dimensional distribution of received photons in Hα flares in the solar atmosphere is presented. It is well known that during flares hydrogen atoms in the chromosphere and photosphere are excited （even ionized） by the downward heating of non-thermal particles and then emit Hα photons. We trace back these Hα photons to their original layers by use of the contribution function in the theory of spectral line formation, and so acquire their three-dimensional （3D） distribution. This technique is applied to the two-ribbon flare of 2.02.January 2.. The atmospheric models are obtained by fitting the ＂quasi-profiles＂ with the help of the generally used model atmospheres. Since the variety of the 3D images reflects the response of the atmospheric layers to the impact of energy transport, an analysis of the development of the flare is given through a comparison of the 3D images with the 2. temperature distribution.

关键词： line: formation - radiative transfer - sun: flares

一个复杂太阳射电爆发及其微波源和远紫外冕环特征的初步研究

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天文学报 2004年第4期45卷 389-401页

作者：王霖谢瑞祥汪敏许春刘玉英中国科学院国家天文台云南天文台昆明650011 中国科学院国家天史台北京100012

利用太阳射电宽带频谱仪(0.7-7.6 GHz)于2.01年10月19目观测到的复杂太阳射电大爆发,呈现出许多有趣的特征.结合NoRH(Nobevama Radio Heliograph)的高空间分辨率射电成像观测及TRACE(Transition Region and Coronal Explorer)在远紫外(EUV)波段的高空间分辨率成像观测资料,分析了该爆发的射电频谱特征和微波射电源的演化以及它们与复杂的EUV日冕环系统的关系.该爆发是一个双带大耀斑的射电表征.前一部分以宽带(从厘米到米波)爆发为主,机制是回旋同步辐射,所对应的是环足源的辐射;后一部分以窄带(分米到米波)分米波爆发为主,机制是等离子体辐射和回旋共振辐射的联合,对应的是环顶源的辐射.

关键词：太阳射电爆发射电源耀斑日冕观测资料微波源演化 EUV 米波宽带

SYMPATHETIC PARTIAL AND FULL FILAMENT ERUPTIONS OBSERVED IN ONE SOLAR BREAKOUT EVENT

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SYMPATHETIC PARTIAL AND FULL FILAMENT ERUPTIONS OBSERVED IN ...

Close Major-merger Pairs at z=0: Star-forming Galaxies with Pseudobulges

强化科技基础推进气象现代化——第2.届中国气象学会年会

作者： yuandeng Shen1,2.3,yu Liu1,3,and Jiangtao Su3 1 {2. astronomical observatory,chinese academy of Sciences,kunming 650011,China 2.Graduate University of chinese academy of Sciences,Beijing 100049,China 3 Key Laboratory of Solar Activity,national astronomical observatories,chinese academy of Science,Beijing 100012.China

We report two sympathetic solar eruptions including a partial and a full flux rope eruption in a quadrupolar magnetic region where a large and a small filament resided above the middle and the east neutral lines,*** large filament first rose slowly at a speed of 8 km s-1 for 2. minutes;it then accelerated to 102.km ***,this filament erupted successfully and caused a coronal mass *** the slow rising phase,various evidence for breakout-like external reconnection has been identified at high and low temperature *** eruption of the small filament started around the end of the large filament’s slow *** filament erupted partially,and no associated coronal mass ejection could be *** on a potential field extrapolation,we find that the topology of the three-dimensional coronal field above the source region is composed of three low-lying lobes and a large overlying flux system,and a null point located between the middle lobe and the overlying antiparallel flux *** propose a possible mechanism within the framework of the magnetic breakout model to interpret the sympathetic filament eruptions,in which the magnetic implosion mechanism is thought to be a possible link between the sympathetic eruptions,and the external reconnection at the null point transfers field lines from the middle lobe to the lateral lobes and thereby leads to the full(partial) eruption of the observed large(small) *** possible mechanisms are also discussed *** conclude that the structural properties of coronal fields are important for producing sympathetic eruptions.

关键词： Sun:activity-Sun:coronal mass ejections(CMEs)-Sun:filaments prominences-Sun:flares-Sun:magnetic topology

来源： cnki会议评论

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Research in Astronomy and Astrophysics 2024年第5期24卷 35-60页

作者：何川徐聪 Ute Lisenfeld 戴昱方陶陶黄家声王炜余清正 chinese academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China School of Astronomy and Space Sciences University of Chinese Academy of SciencesBeijing 100049China Departamento de Física Teórica y del Cosmos Universidad de Granada18071 GranadaSpain Instituto Carlos I de Física Téorica y Computacional Facultad de Ciencias18071 GranadaSpain Department of Astronomy Xiamen UniversityXiamen 361005China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China

We present a study of star-forming galaxies (SFGs) with pseudobulges (bulges with Sérsic index n2.) mean of specific star formation rate (sSFR) enhancement (sSFR_(enh)=0.33±0.07 versus sSFR_(enh)=0.12.0.06) and br... 详细信息

We present a study of star-forming galaxies (SFGs) with pseudobulges (bulges with Sérsic index n2. in a loca close major-merger galaxy pair sample (H-KPAIR).With data from new aperture photometries in the optical and near-infrared bands (aperture size of 7 kpc) and from the literature,we find that the mean Age of central stellar populations in Spirals with pseudobulges is consistent with that of disky galaxies and is nearly constant against the bulge-to-total ratio (B/T).Paired Spirals have a slightly lower fraction of pure disk galaxies (B/T≤0.1) than their counterparts in the control *** to SFGs with classical bulges,those with pseudobulges have a higher (>2.) mean of specific star formation rate (sSFR) enhancement (sSFR_(enh)=0.33±0.07 versus sSFR_(enh)=0.12.0.06) and broader scatter (by~1 dex).The eight SFGs that have the highest sSFR_(enh)in the sample all have pseudobulges.A majority (69%) of paired SFGs with strong enhancement (having sSFR more than5 times the median of the control galaxies) have *** Spitzer data show that the pseudobulges in these galaxies are tightly linked to nuclear/circum-nuclear *** SFGs in S+S and in S+E pairs have significantly (>3σ) different sSFR enhancement,with the means of sSFR_(enh)=0.45±0.08 and-0.04±*** find a decrease in the sSFR enhancements with the density of the environment for SFGs with *** a high fraction (5/11) of pseudobulge SFGs in S+E pairs are in rich groups/clusters (loca density N_(1Mpc)≥7),the dense environment might be the cause for their low s SFR_(enh).

关键词： galaxies evolution-galaxies interactions-galaxies star formation-galaxies structure-galaxies bulges-galaxies photometry

Refiector Deformation Measurement and Correction Methodology of Large Antenna Based on Phased Array Feed

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Research in Astronomy and Astrophysics 2024年第3期24卷 297-308页

作者： Zan Wang De-Qing Kong Hong-Bo Zhang Yan Su Xin-Ying Zhu cong-Si Wang yu-Chen Liu Key Laboratory of Lunar and Deep Space Exploration National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China University of chinese academy of Sciences Beijing 100049China Key Laboratory of Electronic Equipment Structure Design Ministry of EducationXidian UniversityXi'an 710071China

To solve the problem of time-consuming measurement and correction of large antennas’reflector deformation,a new microwave holography methodology based on a Phased Array Feed(PAF)is *** from the known expression of receiving signals in microwave holography,the theory of PAF holography is derived through Geometrical *** deformation,as well as pointing deviation and subreflector offset,can be calculated out by applying the derived equations.A measurement and correction system based on PAF holography is depicted,and two kinds of measurement methods are *** proposed measurement methodology is verified by numerical simulation,and its measurement error is *** results indicate that our proposed methodology is feasible,especially for Cassegrain antennas.

关键词： telescopes-methods analytical--methods numerical

Resolution Enhancement of SOHO/MDI Magnetograms

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Research in Astronomy and Astrophysics 2024年第6期24卷 358-367页

作者： Ying Qin Kai-Fan Ji Hui Liu Xiao-Guang yu yunnan observatories Chinese Academy of SciencesKunming 650011China University of chinese academy of Sciences Beijing 100049China yunnan Key Laboratory of Solar Physics and Space Science Kunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China

Research on the solar magnetic field and its effects on solar dynamo mechanisms and space weather events has benefited from the continual improvements in instrument resolution and measurement *** augmentation and assimilation of historical observational data timelines also play a significant role in understanding the patterns of solar magnetic field *** the realm of astronomical data processing,super-resolution(SR)reconstruction refers to the process of using a substantial corpus of training data to learn the nonlinear mapping between low-resolution(LR)and high-resolution(HR)images,thereby achieving higherresolution astronomical *** paper is an application study in high-dimensional nonlinear *** learning models were employed to perform SR modeling on SOHO/MDI magnetograms and SDO/HMI magnetograms,thus reliably achieving resolution enhancement of full-disk SOHO/MDI magnetograms and enhancing the image resolution to obtain more detailed *** this study,a data set comprising 9717pairs of data from 2.10 April to 2.11 February was used as the training set,1332.pairs from 2.11 March were used as the validation set and 1034 pairs from 2.11 April were used as the test *** data preprocessing,we randomly cropped 12.×12. sub-images as the LR cases from the full-disk MDI magnetograms,and the corresponding 512.512.sub-images as HR ones from the HMI full-disk magnetograms for model *** tests conducted have shown that the study successfully produced reliable 4×SR reconstruction of full-disk MDI *** MESR model's results(0.911)were highly correlated with the target HMI magnetographs as indicated by the correlation coefficient ***,the method achieved the best PSNR,SSIM,MAE and RMSE values,indicating that the MESR model can effectively reconstruct magnetograms.

关键词： magnetic fields techniques:image processing virtual observatory tools Sun:magnetic fields

Observation of spectral lines in the exceptional GRB 2.1009A

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 187-206页

作者： Yan-Qiu Zhang Shao-Lin Xiong Ji-Rong Mao Shuang-Nan Zhang Wang-Chen Xue Chao Zheng Jia-cong Liu Zhen Zhang Xi-Lu Wang Ming-yu Ge Shu-Xu Yi Li-Ming Song Zheng-Hua An Ce Cai Xin-Qiao Li Wen-Xi Peng Wen-Jun Tan Chen-Wei Wang Xiang-Yang Wen yue Wang Shuo Xiao Fan Zhang Peng Zhang Shi-Jie Zheng Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of chinese academy of Sciences Beijing 100049China yunnan observatories Chinese Academy of SciencesKunming 650011China Center for astronomical Mega-Science Chinese Academy of SciencesBeijing 100012China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China College of Physics and Hebei Key Laboratory of Photophysics Research and Application Hebei Normal UniversityShijiazhuang 050024China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550001China College of Electronic and Information Engineering Tongji UniversityShanghai 201804China

As the brightest gamma-ray burst ever observed,GRB 2.1009A provided a precious opportunity to explore spectral line *** this article,we performed a comprehensive spectroscopy analysis of GRB 2.1009A jointly with GECAM-C and Fermi/GBM data to search for emission and absorption *** the first time we investigated the line feature throughout this GRB including the most bright part where many instruments suffered problems,and identified prominent emission lines in multiple time *** central energy of the Gaussian emission line evolves from about 37 to 6 MeV,with a nearly constant ratio(about 10%)between the line width and central ***,we find that both the central energy and the energy flux of the emission line evolve with time as a power law decay with power law index of–1 and–2.*** suggest that the observed emission lines most likely origin from the blue-shifted electron positron pair annihilation 511 ke V *** find that a standard high latitude emission scenario cannot fully interpret the observation,thus we propose that the emission line comes from some dense clumps with electron positron pairs traveling together with the *** this scenario,we can use the emission line to directly,for the first time,measure the bulk Lorentz factor of the jet(Γ)and reveal its time evolution(i.e.,Γ~t^(-1))during the prompt ***,we find that the flux of the annihilation line in the co-moving frame keeps *** discoveries of the spectral line features shed new and important lights on the physics of GRB and relativistic jet.

关键词： GRB GRB 2.1009A emission line

A New Formulation for General Relativistic Force-Free Electrodynamics and Its Applications

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chinese Journal of Astronomy and Astrophysics 2007年第6期7卷 743-756页

作者： cong yu national astronomical {2. / yunnan observatory Chinese Academy of Sciences Kunming 650011

We formulate the general relativistic force-free electrodynamics in a new 3 ＋ 1 language. In this formulation, when we have properly defined electric and magnetic fields, the covariant Maxwell equations could be cast in the traditional form with new vacuum constitutive constraint equations. The fundamental equation governing a stationary, axisymmetric force-free black hole magnetosphere is derived using this formulation which recasts the Grad-Shafranov equation in a simpler way. Compared to the classic 3＋1 system of Thorne and MacDonald, the new system of 3＋1 equations is more suitable for numerical use for it keeps the hyperbolic structure of the electrodynamics and avoids the singularity at the event horizon. This formulation could be readily extended to non-relativistic limit and find applications in fiat spacetime. We investigate its application to disk wind, black hole magnetosphere and solar physics in both fiat and curved spacetime.

关键词： method analytical -- magnetic fields -- accretion --jet -- relativity