国际天球参考系

金文敬^1,2　夏一飞³　唐正宏^1,2　王叔和^1,2

^{(1.中国科学院上海天文台　上海　200030)}

^{(2.中国科学院国家天文观测中心　北京　100012)}

(3.南京大学天文系　南京　210093)

摘　　　要

    阐述了1998年1月1日起IAU采用的国际天球参考系的定义，以及它与以往采用的光学天球参考架
FK5的关系。介绍了国际天球参考系在射电波段的实现过程、其稳定性的维持方法和它与依巴谷星
表之间的关系。重点描述了影响国际天球参考架稳定性的物理因素---河外射电源的结构及其变化、
射电源喷流的视超光速现象和由银河系盘星和大质量致密晕的引力透镜效应引起的视自行等。最后，
对我国VLBI基地在河外射电参考架维持方面可以开展的课题提出了若干建议。

International Celestial Reference System

Jin Wenjing^1,2 Xia Yifei³ Tang Zhenghong^{1,2 Wang Shuhe1,2}

(1 Shanghai Astronomical Observatory, The Chinese Academy of Sciences, Shanghai 200030)

(2 National Astronomical Observatories, The Chinese Academy of Sciences, Beijing 100012)

(3 Astronomy Department, Nanjing University, Nanjing 210093)

Abstract

Since January 1, 1998 the International Celestial Reference System (ICRS) has been adopted by IAU. In this paper, the definition of the ICRS, the relation between ICRS and FK5, which is the previous optical celestical reference frame, are described. The procedure of the realization of ICRS in the radio wavelength, the method of maintenance of ICRS and the linkage between various reference frames such as ICRS and Hipparcos Catalogue, ICRS and ephemeris DE200 are also introduced. The influences of the physical characteristics of radio sources on the stability of International Celestial Reference Frame (ICRF) such as the structure and `proper motion' of extragalactic radio sources, superluminal phenomenon of the jet of radio source and the gravitational lensing due to the the disk stars and MACHOs in our Galaxy are emphasized. Finally, authors suggest some research subjects to be developed for the contribution of Chinese VLBI network to the maintenance of extragalactic reference frame with sub-milliarcsecond accuracy.

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