Gaia Data Release 1: Astrometry - one billion positions, two million proper motions and parallaxes
Gaia Data Release 1: Astrometry - one billion positions, two million proper motions and parallaxes
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DOI：
10.1051/0004-6361/201628714
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发表时间：
2016-09
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通讯作者：
L. Lindegren;U. Lammers;U. Bastian;J. Hern'andez;S. Klioner;D. Hobbs;A. Bombrun;D. Michalik
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作者：
L. Lindegren;U. Lammers;U. Bastian;J. Hern'andez;S. Klioner;D. Hobbs;A. Bombrun;D. Michalik
盖亚数据发布1（盖亚DR 1）包含超过10亿颗亮度超过20.7等的恒星的天体测量结果，这些结果是基于盖亚卫星在其运行阶段的前14个月收集的观测结果。我们给出了一个简短的概述的天体测量内容的数据发布和模型的假设，数据处理和验证的结果。对于与依巴谷和第谷-2星表相同的恒星，通过合并早期星表的位置信息，可以得到完整的天体测量单星解。对于其他恒星，只有它们的位置是通过忽略它们的自行和自转得到的。通过残差分析、特殊验证运行以及与外部数据进行比较，对结果进行验证。结果对于大约200万颗较亮的恒星（低至11.5等），我们获得了依巴谷型精度或更高的位置、视差和自行。对于这些恒星，取决于例如位置和颜色的系统误差在0.3毫角秒（mas）的水平。对于其余的恒星，我们获得的位置在历元J2015.0精确到~10 mas。位置和自行是在一个参考系中给出的，该参考系与国际天体参考系（ICRF）对齐，在历元J2015.0时优于0.1 mas，并且相对于ICRF不旋转，在0.03 mas/yr内。依巴谷参考系相对于盖亚DR 1参考系以0.24 mas/yr的速率旋转。基于不到四分之一的标称使命长度和非常临时和不完整的校准，盖亚DR 1中天体测量数据的质量和完整性远远低于对最终使命产品的预期。然而，这些结果代表了现有的基本恒星数据和光学参考系的实际定义的巨大改进。
Gaia Data Release 1 (Gaia DR1) contains astrometric results for more than 1 billion stars brighter than magnitude 20.7 based on observations collected by the Gaia satellite during the first 14 months of its operational phase. We give a brief overview of the astrometric content of the data release and of the model assumptions, data processing, and validation of the results. For stars in common with the Hipparcos and Tycho-2 catalogues, complete astrometric single-star solutions are obtained by incorporating positional information from the earlier catalogues. For other stars only their positions are obtained by neglecting their proper motions and parallaxes. The results are validated by an analysis of the residuals, through special validation runs, and by comparison with external data. Results. For about two million of the brighter stars (down to magnitude ~11.5) we obtain positions, parallaxes, and proper motions to Hipparcos-type precision or better. For these stars, systematic errors depending e.g. on position and colour are at a level of 0.3 milliarcsecond (mas). For the remaining stars we obtain positions at epoch J2015.0 accurate to ~10 mas. Positions and proper motions are given in a reference frame that is aligned with the International Celestial Reference Frame (ICRF) to better than 0.1 mas at epoch J2015.0, and non-rotating with respect to ICRF to within 0.03 mas/yr. The Hipparcos reference frame is found to rotate with respect to the Gaia DR1 frame at a rate of 0.24 mas/yr. Based on less than a quarter of the nominal mission length and on very provisional and incomplete calibrations, the quality and completeness of the astrometric data in Gaia DR1 are far from what is expected for the final mission products. The results nevertheless represent a huge improvement in the available fundamental stellar data and practical definition of the optical reference frame.