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Variability in Blazars

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天文研究与技术 2003年第S1期 107-116页

作者： Xie guang zhong (national astronomical observatories/yunnan observatory,, CAS, yunnan kunming 650011, P. R. China

In this report, a review of historical observations and studies to the variability in blazars is given. The variability timescale, in particular, the optical variability timescale, is emphasized owing to its importance. Three samples of three different kinds of variations are presented, and the corresponding models to interpret them are given. The long periodic variability is paid a lot of attention because which could be explained by the eclipses of the binary supermassive black holes (SMBHs). In addition, the observed evidences, such as the periodic outbursts in OJ 287, supporting the binary SMBHs model are also presented. A brief conclusion and prospect is presented at the end of this report.

关键词： Nature AS in Variability in Blazars ARA Mark

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云南天文台对流星的视频观测

天文学报 2004年第2期45卷 186-194页

作者：吴光节张周生中国科学院国家天文台云南天文台昆明650011

近20年来,随着CCD和像增强器的发展,小巧灵活的流星视频观测系统在世界上逐渐多了起来。并且,最终将可能逐步取代流星的目视观测和普通照相观测。介绍云南天文台Ⅰ号流星彗星视频照相系统的研制及其初步观测结果。这一系统由容易转换的... 详细信息

近20年来,随着CCD和像增强器的发展,小巧灵活的流星视频观测系统在世界上逐渐多了起来。并且,最终将可能逐步取代流星的目视观测和普通照相观测。介绍云南天文台Ⅰ号流星彗星视频照相系统的研制及其初步观测结果。这一系统由容易转换的5组件构成。用于流星观测的大视场相机的视场约36度,单帧图像可观测到约6等恒星。实测的恒星星等测量精度可达约0.2等。还讨论了视频照相机比传统的感光胶卷照相的长处,以及视频照相系统的改进与发展。

关键词：云南天文台流星视频观测探测器

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我国古代记录的特殊流星现象与现代印证

天文学报 2003年第2期44卷 156-165页

作者：吴光节张周生中国科学院国家天文台云南天文台昆明650011

中国古代有着大量的对于流星和流星雨的观测记录,最早可以追溯到3000多年以前。在这些珍贵的记录中,不仅有对于流星的一般描述,而且还有一些至今不能完全理解的特殊流星现象的记录。基于现代对电声变换流星声、流星体的螺旋线形运动、... 详细信息

中国古代有着大量的对于流星和流星雨的观测记录,最早可以追溯到3000多年以前。在这些珍贵的记录中,不仅有对于流星的一般描述,而且还有一些至今不能完全理解的特殊流星现象的记录。基于现代对电声变换流星声、流星体的螺旋线形运动、流星的颜色变化和流星的分裂等等的研究,列出在中国古代文献中可以查找到的有关记录。这些记录,不仅是世界文化宝库的一部分,而且对于今天的研究仍有实用价值。对电声变换流星声的报道,只是近20年来,才确立了的并非是观测者的臆想。流星的现代彩色照相观测,更真实地记录和展现了其他的特殊流星现象和它们的发生与演变。这些古代记录与现代的流星观测的对比,可以起到相互印证的作用。

关键词：流星流星雨太阳系照相观测

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狮子座流星雨1999年照相观测的分析

天文学报 2001年第4期42卷 390-396页

作者：张周生吴光节中国科学院云南天文台昆明650011

对 1 999年 1 1月 1 9日拍摄的两张狮子座流星胶片进行了分析研究 .照相观测比目视观测记录了更多的定量信息 .计算了流星在胶片上显露时必须满足的运动角速度条件 ,求出了流星起始点仰角、流星结束点与辐射点的角距离、流星运动的角速... 详细信息

对 1 999年 1 1月 1 9日拍摄的两张狮子座流星胶片进行了分析研究 .照相观测比目视观测记录了更多的定量信息 .计算了流星在胶片上显露时必须满足的运动角速度条件 ,求出了流星起始点仰角、流星结束点与辐射点的角距离、流星运动的角速度以及流星路径的弧长等 .并且得出流星在大气中的烧蚀时间仅 0 .6 5秒左右 ,即烧蚀的路径长约 40 - 5 0公里 .通过在扫描仪上得到的黑白图像的处理 ,求得两颗流星的照相星等分别为 - 1 0 .3± 0 .2和 - 4.8± 0 .2 .由此可以得到它们的质量和电子线密度 .给出的处理方法 ,也可用于其他流星的照相观测资料处理 .并且 ,对流星观测使用的照相镜头也进行了讨论 .

关键词：狮子座流星雨照相观测星等角距离烧蚀

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地外生命搜索和太阳系外的行星的发现

天文学报 2001年第3期42卷 225-239页

作者：吴光节陈道汉中国科学院云南天文台中国科学院国家天文台北京100012 中国科学院紫金山天文台

阐述地外生命搜索的意义、手段和现状 ,地外生命搜索的SETI计划及其发展 .并着重介绍太阳系外的行星系统的发现 ,它的目的、方法、成果以及未来 .太阳系外的行星系统的发现是当代天文学最时髦的、也将是未来 2.1世纪成果最丰富的研究领... 详细信息

阐述地外生命搜索的意义、手段和现状 ,地外生命搜索的SETI计划及其发展 .并着重介绍太阳系外的行星系统的发现 ,它的目的、方法、成果以及未来 .太阳系外的行星系统的发现是当代天文学最时髦的、也将是未来 2.1世纪成果最丰富的研究领域之一 .从 1 992年第一个确认了脉冲星PSR 1 2 5 7+1 2的行星系统以来 ,1 995年确认主序星 5 1Peg有一颗行星 ,至 2 0 0 1年 5月 ,已经发现了 6 0个太阳系外的行星系统 .太阳系外的行星系统的发现与地外生命搜索研究是密不可分的 .新的发现也提出了很多新的谜 .这项研究近 1 0年来发展很快 .它的研究也促进了航天学、宇宙化学、天文生物学乃至哲学等其他学科的发展 .

关键词：地外生命太阳系行星探测方法

The Relation between Masses of Central Supermassive Black Holes and Bolometric Luminosities md Implications for Evolutionary Sequence of Blazars

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The Relation between Masses of Central Supermassive Black Ho...

Resolution Enhancement of SOHO/MDI Magnetograms

黑洞物理研讨会

作者： Liang En-Wei and Xie guang-Zhong national astronomical observatories/yunnan observatory, chinese academy of sciences, kunming 650011, P.R.China Physics Department, guangxi University, Nanning 530004, P. R. China yunnan Astrophysics Center, yunnan University, kunming 650091, P. R. China

A sample including 39 blazars, which rapid variation timescales and bolometric luminosities are well established, has been compiled from literature. Based on a assumption that central supermassive black holes (SMBHs) hosted in these objects axe rapidly rotating with possible rate, the upper limits of their masses were estimated with the rapid variation timescales. The results show that the masses range from 107.3M⊙to 109.4M⊙, showing a bimodal distribution with peaks at 10 8.2M⊙and 109.2M⊙, and a valley at 108.7M⊙. Accordingly, these objects were classified into two groups by the division of M = 108.7M⊙, namely group Ⅰand group Ⅱfor objects with M 108.7M⊙and M > 108.7M⊙, respectively. All BL Lac objects in the sample are included into the group Ⅰ(BL Lac-liked objects). About half of FSRQs are included the group Ⅰ, and the another belong to the group Ⅱ(FSRQ-liked objects). These results are quite consistent with our previous results. The mass-luminosity relations for the objects in the two groups were also investigated. They are significantly different. A robust regression analysis gives the relations are logL/L⊙= 2.8×logM/M⊙- 10 and logL/L⊙= 4.0 ×logM/M⊙- 23 for the BL Lac-liked objects (group Ⅰ) and the FSRQ-liked objects (group Ⅱ), respectively. The relations are quite similar to that derived from stars in main sequence. In addition, possible implications for blazars evolutionary sequence of blazars are discussed. These results might imply the allowance of the switch from FSRQs to BL Lacs and the forbiddance of the transition of BL Lacs to FSRQS, and the different energy sources that powered the observed luminosities for the two types of objects. These are consistent with D’Elia & Cavaliere (2000) and Bottcher & Dermer (2001) suggestions. Based on the D’Elia & Cavaliere’s argument that the blazar sequence should be invoked an extremely galaxy-galaxy merger, and the Begelman et al.’s argument (1980) that a binary black hole system might be formed in a galaxy-gala

关键词： active galactic nuclei black hole evolution

来源： cnki会议评论

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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 128×128 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

Effects of Redshift on the Classifying Criteria of BL Lacertae Objects

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chinese Journal of Astronomy and Astrophysics 2007年第3期7卷 345-352页

作者： Li Ma Luo-En Chen guang-Zhong Xie Ji-Yang Ren Zhao-Hua Xie Shu-Bai Zhou Hui wu Dong-Cheng Mei Department of Physics Yunnan Normal University Kunming 650092 Department of Physics Yuxi Normal College Yuxi 653100 national astronomical observatories/yunnan observatory Chinese Academy of Sciences Kunming 650011 Department of Physics Yunnan University Kunming 650091

We have collected a sample of 70 BL Lacs （33 radio-selected BL Lacs and 37 X-ray selected BL Lacs） with multi-waveband data for investigating the classifying criteria of BL Lacertae Objects. For each source, we estimate its luminosities in radio, optical and X-ray, the broad-band spectral index from radio to X-ray and the peak frequency of the synchrotron emission, and make a statistical analysis of the data obtained. Our main results are as follows：（1） The broad-band spectral index and the peak frequency have no correlation with the redshift, while they are inversely correlated with each other and they could be regarded as equivalent classifying criteria of BL Lac objects. （2） There are significant effects of the luminosity/redshift relation on the observed luminosity distribution in our sample, hence, if the radio luminosity is to be used as a classifying criterion of BL Lac objects, it should not be regarded as equivalent to the broad-band spectral index or the peak frequency. （3） Our resuits supply a specific piece of evidence for the suggestion that the use of luminosities always introduces a redshift bias to the data and show that the location of the peak frequency is not always linked to the luminosity of any wave band.

关键词： galaxies BL Lacertae objects general-galaxies fundamental parametersgalaxies high-redshift