共查询到20条相似文献，搜索用时 31 毫秒
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In order to test the systematics of the Amati relation, 24 long-duration GRBs with available Eγ,iso, and Ep are separated into two subgroups according to the B-band luminosity of their host galaxies. The Amati relations in the two subgroups are found to be in agreement with each other within the uncertainties. Taking into account of the well established luminosity-metallicity relation of galaxies, no strong evolution of the Amati relation with the GRB's environmental metallicity is implied in this study. 相似文献
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Li-Cai Deng Heidi Jo Newberg Chao Liu Jeffrey L. Carlin Timothy C. Beers Li Chen Hsu-Tai Lee Carl J. Grillmair Puragra Guhathakurta Zhan-Wen Han Jin-Liang Hou Sebastien Lepine Jing Li Xiao-Wei Liu Kai-Ke Pan J. A. Sellwood Bo Wang Hong-Chi Wang Fan Yang Brian Yanny Hao-Tong Zhang Yue-Yang Zhang Zheng Zheng Zi Zhu 《天体物理学报》2012,(7):735-754
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Hui-Hua Zhang Xiao-Wei LiU Hai-Bo Yuan Hai-Bin Zhao Jin-Sheng Yao Hua-Wei Zhang Mao-Sheng Xiang Yang Huang 《中国天文和天体物理学报》2014,(4):456-470
We present astrometric calibration of the Xuyi Schmidt Telescope Photometric Survey of the Galactic Anti-center(XSTPS-GAC). XSTPS-GAC is the photometric part of the Digital Sky Survey of the Galactic Anti-center(DSS-GAC),which is a photometric and spectroscopic sky survey, in combination with LAMOST.In order to select an astrometric reference catalog, we made comparisons between the four widely used astrometric catalogs, GSC2.3, USNO-B1.0, UCAC3 and PPMXL.PPMXL shows relatively small systematic errors in positions and more homogeneous proper motion distributions toward the Galactic Anti-center(GAC), and was selected as the reference catalog. Based on the high quality and bright reference stars that were picked out from PPMXL, we performed a 4th-order polynomial fitting in image units,to construct the transformation relation between coordinates used by XSTPS-GAC and standard coordinates, and to simultaneously correct the image distortions in the CCD. Then we applied the derived relation to all sources to obtain their mean celestial coordinates based on the International Celestial Reference System. For bright point sources with r 17.0 mag, the accuracy of astrometric calibration could reach about80 mas for each of the g, r, i bands, with systematic errors being less than 10 mas. But for the faint sources at the brightness limit of the survey, which was r ～ 19.0 mag, the accuracy can still reach 200 mas. After combining all observations, the final weighted average coordinates could reach an accuracy of less than 70 mas for bright stars. For faint stars, the rms residuals of weighted coordinates decrease to ～ 110 mas. The final combined XSTPS-GAC coordinates show a good consistency with the Sloan Digital Sky Survey. 相似文献
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开始观测
首先,在选定的观测地点摆放好观测所需的物品,做好观测前的准备工作,躺好后开始进行观测。流星雨标准观测需要高度集中注意力以及快速反应,所以在观测过程中请不要听音乐或做其他过于分散注意力的事情。在正式开始标观前,你还需要做以下几件事： 相似文献
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流星雨标准观测（以下简称“标准观测”）,是按照国际流星组织（IMO）规定的方法对流星、流星雨（群）进行观测。得到可以用于进行科学分析的数据的观测方法。本文将按照标准观测的要求,结合作者的实际观测经验。整理出流星雨观测的科学方法。和大家共享。 相似文献
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ＡＧＮ天体的主要特征之一，就是它们的光谱中有宽而强的发射线，因此，这些宽发射线的产生区域ＢＬＲ为人们提供了一个了解ＡＧＮ天体物理本质的独特而重要的场。在文中围绕讨论了ＢＬＲ基本物理特征，评述近年来有关的理论和观测研究进展及其现状在文（Ⅱ）中主要涉及ＢＬＲ的几何结构和尺度及其运动学研究的进展和现状。 相似文献
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ＡＧＮ天体的主要特征之一，就是它们的光谱中有宽而强的发射线，因此，这些宽发射线的产生区域ＢＬＲ为人们提供了一个了解ＡＧＮ天体物理本质的独特而重要的场所。在文中围绕讨论ＢＬＲ的基本物理特征，评述近年来有关的理论和观测研究进展及其现状。在文（Ⅰ）中将重点介绍和讨论ＢＬＲ研究的基本理论框架，即气体云闭的光致电离模型以及发射线云闭的起源和约束问题。 相似文献
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日本是天文馆大国,无论是天文馆的建设和运营,还是天象仪的制造,以及天文馆软件开发等方面,都是世界一流的。在中小型天文馆和中小型天象仪方面也是如此。根据日本天文馆协会2005年的《天文馆白皮书》,它所统计到的中小型天文馆就有253座,从拥有的数量来说,日本的中小型天文馆继美国之后,居世界第二位。日本天象仪制造业发达,其两大制造商——五藤和美能达,从创立之初,就把开发和经营中小型天象仪放置在与大型天象仪同样重要的地位,从一开始就把他们的大中小产品编成系列,加以推广,并不断推陈出新。 相似文献
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A wide-field time-series CCD photometric survey of variable stars in the field of the open cluster NGC 2168 was carried out using the BATC Schmidt telescope. In total 13 new variable stars are discovered with three W UMa systems, one EA type and two EB type eclipsing binaries (one of them could be a W UMa system), and seven pulsating stars including three candidates of δScuti stars. 相似文献
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The extragalactic diffuse emission at γ-ray energies has interesting cosmo-logical implications since these photons suffer little or no attenuation during their prop-agation from the site of origin. The emission could originate from either truly diffuse processes or from unresolved point sources such as AGNs, normal galaxies and starburst galaxies. Here, we examine the unresolved point source origin of the extragalactic γ-ray background emission from normal galaxies and starburst galaxies. γ-ray emission from normal galaxies is primarily coming from cosmic-ray interactions with interstellar mat-ter and radiation (～90%) along with a small contribution from discrete point sources (～10%). Starburst galaxies are expected to have enhanced supernovae activity which leads to higher cosmic-ray densities, making starburst galaxies sufficiently luminous at γ-ray energies to be detected by the current γ-ray mission (Fermi Gamma-ray Space Telescope). 相似文献