共查询到19条相似文献,搜索用时 171 毫秒
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DCMT活动光栅的控制系统是主测微器的主要部分,本控制系统操作灵活,它既能联机工作又能脱机工作,并具有自动报警和自动复位功能。主测微器承担测定天体和5个自准直像的位置,要比传统的活动光栅复杂得多.本设计的独特之处在于用分区、分时并配以光栏控制诸方法确定全部像的位置。保证了所有的观测在同一个系统之内.经一年来的实际观测证明,本系统精度优于0”.03,达到了同类别微器的先进水平. 相似文献
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射电天文已成为人类研究宇宙的重要途径。但随着人类生产、生活的发展,射频干扰信号对射电天文观测的影响越来越严重,观测数据的好坏关系到科学成果的质量甚至结论的真伪。目前广泛采用基于阈值判断射频干扰,对干扰信号直接舍弃部分观测数据的方法。此类方法存在阈值确定困难、观测带宽和时间被缩减等问题。针对脉冲星观测射电信号中,各干扰信号及射电信号统计独立以及呈现出的非高斯性,利用独立成分分析对混合信号进行分解,并根据观测信号中脉冲星信号和干扰信号的分布特点识别脉冲星信号,实现干扰信号消除。使用该方法对云南天文台40 m射电望远镜接收到的脉冲星观测信号进行独立成分分析,分解出独立的射频干扰信号和脉冲星信号,消除射频干扰信号。独立成分分析法在干扰信号消除、射电信号保留及信噪比方面均取得良好效果。 相似文献
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黄天君 孙天瑞 胡镭 宁宗军 吴雪峰 王力帆 王晓峰 朱镇熹 UDDIN Ashraf Sye ASHLEY Charles Brewster Michael 《天文学报》2019,60(5):98-114
AST3-2 (Antarctic Survey Telescopes)光学巡天望远镜位于南极大陆最高点冰穹A,其产生的大量观测数据对数据处理的效率提出了较高要求.同时南极通信不便,数据回传有诸多困难,有必要在南极本地实现自动处理AST3-2观测数据,进行变源和暂现源观测的数据处理,但是受到低功耗计算机的限制,数据的快速自动处理的实现存在诸多困难.将已有的图像相减方案同机器学习算法相结合,并利用AST3-2 2016年观测数据作为测试样本,发展一套的暂现源及变源的筛选方法成为可行的选择.该筛选方法使用图像相减法初步筛选出可能的变源,再用主成分分析法抽取候选源的特征,并选择随机森林作为机器学习分类器,在测试中对正样本的召回率达到了97%,验证了这种方法的可行性,并最终在2016年观测数据中探测出一批变星候选体. 相似文献
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时序资料的时间窗平滑法及应用 总被引:3,自引:0,他引:3
观测资料的平滑处理,是数据分析中一类重要的常用方法,平滑处理的目的,在于既保留资料中的主要有用信号,又消除或削弱随机误差,本文对密集采样时序资料,提出了时间窗平滑法,并以光谱和光电测量资料为例,通过分析PDM技术中拟合曲线的计算,说明了它的性质与应用,与高斯权函数平滑法相比,此方法计算简便,且有更明确的物理意义,与观测值多点合并法相比,有更好的采样一致性和避免损失实际的分辨率,当用于等间距时序资料 相似文献
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使用快速鲁棒性主成分分析(Fast Robust Principal Component Analysis,Fast RPCA)方法对日冕序列图像中的日冕喷流活动进行检测。检测的基本思路是利用快速鲁棒性主成分分析方法中低秩和稀疏分解的思想与日冕序列图像中有着变化尺度稍小且占比较大的随机变化背景成分、变化尺度较大且占比较小的日冕喷流的特点相结合,实现随机复杂多变的动态背景和稀疏运动目标之间的分离,从而检出作为前景变化的日冕喷流。采用太阳动力学天文台(Solar Dynamics Observatory,SDO)卫星的大气成像仪(Atmospheric Imaging Assembly,AIA)两组不同时间段、不同波段、不同观测位置的日冕序列图像作为研究对象。研究内容主要包括日冕序列图像的预处理、日冕喷流检测、快速鲁棒性主成分分析方法与帧间差分法的检测结果对比分析。实验结果表明,与帧间差分法相比,快速鲁棒性主成分分析方法能够检出强度较弱的日冕喷流,且提高了日冕喷流检测的准确度。 相似文献
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白矮-主序双星是银河系中最常见的致密双星系统,它包含一颗白矮星主星和一颗小质量主序星伴星,由主序双星演化而来。大约1/4的白矮-主序双星经历过一个公共包层演化阶段,其轨道间距较小,周期很短,被称为后共包层双星;而另外3/4的白矮-主序双星则从未经历过公共包层演化,其轨道间距几乎与其最初的主序双星的相同,被称为宽距白矮-主序双星。在光学波段,一般从白矮-主序双星的光谱上能明显地看出其有两个成分。随着大型巡天项目如SDSS、LAMOST巡天的开展,近年来搜寻到的白矮-主序双星的数目越来越多。通过对搜寻到的白矮-主序双星进行大量的后续观测,己从中发现并确认了一大批后共包层双星。利用观测到的白矮-主序双星及后共包层双星样本,有助于我们进一步理解密近双星的演化过程,尤其是公共包层演化的物理机制等重要的天体物理热点议题。介绍了白矮-主序双星的形成和演化,回顾了大型巡天项目中自矮-主序双星的系统搜寻,以及基于这些白矮-主序双星样本获得的研究成果,最后对白矮-主序双星的搜寻研究做了展望。 相似文献
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1984年5月5日太阳东边缘土 墩日珥的Hα单色像和D3线被观测到了。D3发射线由两部分组成:主成分和致宽成分。本文利用双层模型方法对该土墩日珥的17条D3发射线成功的进行了计算,给出了D3线的计算结果。计算结果表明:日珥的D3发射线主要由热的多普勒贡和微观湍流致宽所致,其它致宽机制的作用可忽略。 相似文献
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In this paper the problem of the classification of natural samples is discussed. An updated version of the G-mode multivariate statistical method for the classification of natural samples, applicable to a wide range of research fields, is discussed in this paper. This method allows an automatic classification in terms of homogeneous taxonomic units, without any a priori knowledge of the taxonomic structure of the natural observations; it provides informations on the different levels of classification present in the data set under study (classes and subclasses), on the level of information residing in each variable, on the level of similarity and/or difference among homogeneous classes.An earlier version of this method has been widely applied in planetary sciences, astrophysics and geological sciences. The authors give here a resumé of the most interesting results obtained in these different research fields, from the geochemistry of lunar samples to asteroids taxonomy to remote sensing of planetary surfaces. This method is extremely reliable and versatile, and it is suggested that its use be widespread whenever the problem of the classification of a large set of natural samples occurs. 相似文献
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巡天观测与高能物理、黑洞天文等领域均有密切的联系.基于星系-超新星二分类问题,研究光谱数据预处理,结合余弦相似度改善PCA(Principal Component Analysis)光谱分解特征提取方法,用SDSS(the Sloan Digital Sky Survey)、WISeREP(the Weizmann Interactive Supernova data REPository)组成的5620条光谱数据集训练支持向量机,可以得到0.498%泛化误差的识别模型和新样本分类概率.使用Neyman-Pearson决策方法建立NPSVM(Neyman-Pearson Support Vector Machine)模型可进一步降低超新星的漏判率. 相似文献
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Augmented Reality consists of merging live images with virtual layers of information. The rapid growth in the popularity of smartphones and tablets over recent years has provided a large base of potential users of Augmented Reality technology, and virtual layers of information can now be attached to a wide variety of physical objects. In this article, we explore the potential of Augmented Reality for astrophysical research with two distinct experiments: (1) Augmented Posters and (2) Augmented Articles. We demonstrate that the emerging technology of Augmented Reality can already be used and implemented without expert knowledge using currently available apps. Our experiments highlight the potential of Augmented Reality to improve the communication of scientific results in the field of astrophysics. We also present feedback gathered from the Australian astrophysics community that reveals evidence of some interest in this technology by astronomers who experimented with Augmented Posters. In addition, we discuss possible future trends for Augmented Reality applications in astrophysics, and explore the current limitations associated with the technology. This Augmented Article, the first of its kind, is designed to allow the reader to directly experiment with this technology. 相似文献
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Rene Hudec 《Journal of Astrophysics and Astronomy》2011,32(1-2):91-95
There are about 3 million astronomical photographic plates around the globe, representing an important data source for various aspects of astrophysics. The main advantage is the large time coverage of 100 years or even more. Recent digitization efforts, together with the development of dedicated software, enables for the first time, effective data mining and data analyses by powerful computers with these archives. Examples of blazars proposed and/or investigated on the astronomical plates are presented and discussed. 相似文献
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分别从物理学和天文学角度引申出天体物理学科,特别关注万有引力在其中扮演的关键角色.无论在综合性大学亦或理工科院校,天文教育均有益于提高学生的科学和人文素养,而天体物理则是天文学的主要内涵.介绍了作者讲授"天体物理"课程的相关信息以及个人认识.最后,以大气簇射μ子产生、啾质量、宇宙加速膨胀等教学案例结束,侧面诠释了作者的"天体物理"教育理念. 相似文献
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分别从物理学和天文学角度引申出天体物理学科, 特别关注万有引力在其中扮演的关键角色. 无论在综合性大学亦或理工科院校, 天文教育均有益于提高学生的科学和人文素养, 而天体物理则是天文学的主要内涵. 介绍了作者讲授``天体物理''课程的相关信息以及个人认识. 最后, 以大气簇射mu子产生、啾质量、宇宙加速膨胀等教学案例结束, 侧面诠释了作者的``天体物理''教育理念. 相似文献
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Kai-Kai Duan Wei Jiang Yun-Feng Liang Zhao-Qiang Shen Zun-Lei Xu Yi-Zhong Fan Fabio Gargano Simone Garrappa Dong-Ya Guo Shi-Jun Lei Xiang Li Mario Nicola Mazziotta Maria Fernanda Munoz Salinas Meng Su Valerio Vagelli Qiang Yuan Chuan Yue Stephan Zimmer 《天文和天体物理学研究(英文版)》2019,(9)
Observing GeV gamma-rays is an important goal of the DArk Matter Particle Explorer(DAMPE)for indirect dark matter searching and high energy astrophysics. In this work, we present a set of accurate instrument response functions for DAMPE(DmpIRFs) including the effective area, point-spread function and energy dispersion, which are crucial for gamma-ray data analysis based on statistics from simulation data. A dedicated software named DmpST is developed to facilitate the scientific analyses of DAMPE gamma-ray data. Considering the limited number of photons and angular resolution of DAMPE, the maximum likelihood method is adopted in DmpST to better disentangle different source components. The basic mathematics and framework regarding this software are also introduced in this paper. 相似文献
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E. Budding V. Bakis A. Erdem O. Demircan L. Iliev I. Iliev O. B. Slee 《Astrophysics and Space Science》2005,296(1-4):371-389
Various branches of observational information, and related physical problems concerning the bright, relatively close, Algol
binary δ Lib are discussed. Times of minimum light confirm the classical Algol status, which, combined with the optical and
IR photometry of Lazaro et al. (2002), provide the basis for a good understanding of the system’s basic parameters. New spectroscopy
from the Coudé spectrograph of the Rozhen Observatory (Bulgaria) allows further information on the model and the mass transfer
process. Very high resolution radio observations would also have much to reveal about astrophysics of the semi-detached configuration,
not only directly, by informing about the outermost envelopes of the components, but indirectly through high accuracy positional
information. We show how this may be related to careful period and astrometric studies. δ Lib thus provides a rich source
of information on the astrophysics of the Algol configuration. 相似文献