Frame Rotator Source

Sources used to compute the Gaia reference frame.The AGIS frame rotator algorithm has two different parts: the reference frame orientation; and the reference frame spin. The reference frame orientation is fixed using the International Earth Rotation and Reference System Service (=IERS) position of a subset of IERS sources defining the third realization of the International Coordinate Reference Frame (Charlot et al., 2020, submitted to A&A), http://hpiers.obspm.fr/icrs-pc/newwww/icrf/index.php. The reference frame spin is defined using the Gaia proper motion of a list of QSOs. The reference frame algorithms have an outliers scheme. Hence for each aspect we provide the considered sources and the used sources actually used, and the number of used sources might be lower than the number of considered sources.

用于计算Gaia参考架（Gaia reference frame）的数据源。AGIS参考架旋转算法包含两个组成部分：参考架定向与参考架自旋。参考架定向通过国际地球自转与参考系统服务（International Earth Rotation and Reference System Service，IERS）提供的部分IERS源的位置数据进行标定，这些源定义了国际坐标参考框架第三版（Charlot等，2020，已提交至《A&A》），相关信息可访问：http://hpiers.obspm.fr/icrs-pc/newwww/icrf/index.php。参考架自旋则通过一批类星体（Quasi-Stellar Objects，QSO）的Gaia自行数据进行定义。该参考架算法内置异常值处理机制。因此针对每个处理环节，我们均提供了候选源与实际使用源的相关信息，且实际使用源的数量可能少于候选源的数量。