第二个天体测量卫星(Gaia)项目的进展

Current Progress on Second Astrometric Satellite(Gaia) Project

简述了第二个天体测量卫星Gaia(将于2013年3月发射)项目的科学意义,并给出了该项目的组织工作和最近的进展。描述了Gaia观测资料处理的基本原理,以及与依巴谷观测资料处理的不同点。介绍了Gaia参考架构建的考虑,以及为了构建微角秒量级的参考架,应在自行中加入系统差改正,如长期光行差、引力波效应、宇宙膨胀各向异性的影响、弱的微引力透镜和微引力透镜噪声效应等。介绍了Gaia光学参考架与射电参考架ICRF-2之间建立联系过程中,选择河外射电源的准则,其中包括源的核漂移和光学长期变化监测等。最后,提出了我国现有设备参与支持Gaia的地基观测,以及正在研制的65m射电天线在射电天体测量方面可以开展的若干课题。

The scientific goals of the second astrometric satellite（Gaia） are briefly described. Gaia will be launched in March 2013.The current progress of this project is presented in this paper,especially the basic principle of observational data processing method is given.The difference between Gaia and Hipparcos data processing is also pointed out.In order to attain the accuracy with micro-arcsecond in proper motion some systematic errors such as secular aberration drift,effects of the low-frequency gravitational wave,the Universe expansion anisotropy,the weak microlensing and the microlensing noise should be considered.The construction of Gaia optical reference frame,including the selection of quasars and the attainable accuracy,is mentioned. As for the link between Gaia reference and the radio reference frame ICRF-2,which is adopted by IAU at the 27 th IAU general assembly,the core drift and detection of luminosity in long-term as accident errors should be considered.Finally,through the collaboration with some countries some research subjects,which can be carried out on ground based observations with current instruments and 65 m radio telescope to be built at Shanghai Astronomical Observatory in China,are suggested to support Gaia observations.