标题： Gaia-verse的完整性第三部分：利用隐藏状态从DR2光曲线推断间隙、检测效率和扫描定律 显示英文标题

标题： Completeness of the Gaia-verse III: using hidden states to infer gaps, detection efficiencies and the scanning law from the DR2 light curves

摘要： 盖亚目录的完整性在很大程度上取决于该空间望远镜随时间的状态。 只有当恒星被检测到一定次数时，才会发布其天体测量、测光和光谱数据产品。 如果科学操作出现中断，检测效率下降，或盖亚偏离了命令扫描定律，则恒星可能会错过潜在的检测，因此不太可能进入盖亚目录。 我们通过开发新的方法来推断盖亚随时间和检测间隙及效率下降的方位和角速度，为从数十亿颗恒星的个体测量中回顾性地确定盖亚在整个任务期间的状态奠定了基础。 我们将这些方法应用于盖亚DR2变星历元测光数据——目前唯一公开可用的盖亚时间序列数据——并将结果公开。 我们提供了一个新的Python包scanninglaw (https://github.com/gaiaverse/scanninglaw)，您可以使用它来轻松预测任意天空位置的盖亚观测时间和检测概率。 显示英文摘要

摘要： The completeness of the Gaia catalogues heavily depends on the status of that space telescope through time. Stars are only published with each of the astrometric, photometric and spectroscopic data products if they are detected a minimum number of times. If there is a gap in scientific operations, a drop in the detection efficiency or Gaia deviates from the commanded scanning law, then stars will miss out on potential detections and thus be less likely to make it into the Gaia catalogues. We lay the groundwork to retrospectively ascertain the status of Gaia throughout the mission from the tens of individual measurements of the billions of stars, by developing novel methodologies to infer both the orientation and angular velocity of Gaia through time and gaps and efficiency drops in the detections. We have applied these methodologies to the Gaia DR2 variable star epoch photometry -- which are the only publicly available Gaia time-series at the present time -- and make the results publicly available. We accompany these results with a new Python package scanninglaw (https://github.com/gaiaverse/scanninglaw) that you can use to easily predict Gaia observation times and detection probabilities for arbitrary locations on the sky.