Connecting VLBI and Gaia Celestial Reference Frames
Connecting VLBI and Gaia Celestial Reference Frames
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DOI：
10.3389/fspas.2016.00028
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发表时间：
2016-09
期刊：
影响因子：
--
通讯作者：
Z. Malkin
中科院分区：
文献类型：
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作者：
Z. Malkin
考虑了射电天体参考系与光学天体参考系之间的链路问题的现状。今后几年在这方面研究的主要目标是准备比较从VLBI观测中获得的光学盖亚天体参考系（GCRF）和第三代无线电国际天体参考系（ICRF3）之间的相互定向和旋转。理想情况下，这两个系统都应该实现ICRS（国际天体参考系统）在微弧秒级的精度。因此，ICRF和GCRF之间的链路精度需要在相似的误差水平下获得，这是一项艰巨的任务，因为不同频段的源位置存在较大的系统和随机误差。在本文中，简要概述了GCRF- ICRF链路的最新工作。讨论了提高GCRF- ICRF链路精度的其他可能性。建议使用光学星等为20$^m$的天文测量射电源，而不是目前计划用于GCRF- ICRF链路的18$^m$。此外，利用射电星也是获得盖亚框架与ICRF之间独立准确定向的一种前瞻性方法。
The current state of the link problem between radio and optical celestial reference frames is considered. The main objectives of the investigations in this direction during the next few years are the preparation of a comparison and the mutual orientation and rotation between the optical {\it Gaia} Celestial Reference Frame (GCRF) and the 3rd generation radio International Celestial Reference Frame (ICRF3), obtained from VLBI observations. Both systems, ideally, should be a realization of the ICRS (International Celestial Reference System) at micro-arcsecond level accuracy. Therefore, the link accuracy between the ICRF and GCRF should be obtained with similar error level, which is not a trivial task due to relatively large systematic and random errors in source positions at different frequency bands. In this paper, a brief overview of recent work on the GCRF--ICRF link is presented. Additional possibilities to improve the GCRF--ICRF link accuracy are discussed. The suggestion is made to use astrometric radio sources with optical magnitude to 20$^m$ rather than to 18$^m$ as currently planned for the GCRF--ICRF link. In addition, the use of radio stars is also a prospective method to obtain independent and accurate orientation between the Gaia frame and the ICRF.