论文标题
使用Gaia DR2解决差异颜色折射和电荷转移效率问题
Using Gaia DR2 to solve differential color refraction and charge transfer efficiency issues
论文作者
论文摘要
2018年发布的Gaia DR2目录提供了有关超过十亿颗恒星的信息，其中包括它们不受大气影响的极其精确的位置，以及G，RP和BP Pass带中的幅度。该信息为改善基于地面的天文统计提供了巨大的潜力。基于Gaia DR2，我们提出了一种方便的方法来校准差异颜色折射（DCR）。此方法仅需要通过选定过滤器采取数十颗恒星的观察。将此方法应用于Yunnan天文台通过1 m和2.4 m望远镜通过不同过滤器捕获的观测值，结果表明，在DCR校正后观察到的和计算位置和计算位置和计算位置之间的残差平均值显着降低。对于我们通过N（NULL）滤波器进行的观察结果，暴露良好的恒星的平均值（O-C）中位数（约15 g-mag）从19 MAS到3 MAS降低，从而达到了更好的准确性，即平均值（O-C）。另一个问题是读出CCD帧时，由电荷传输效率差（CTE）造成的系统错误。对于1-M望远镜在云南天文台捕获的某些观察结果，此系统误差很明显。使用Sigmoidal函数拟合和纠正平均值（O-C），可以消除最高30 mas的系统误差。
The Gaia DR2 catalog released in 2018 gives information about more than one billion stars, including their extremely precise positions that are not affected by the atmosphere, as well as the magnitudes in the G, RP, and BP passbands. This information provides great potential for the improvement of the ground-based astrometry. Based on Gaia DR2, we present a convenient method to calibrate the differential color refraction (DCR). This method only requires observations with dozens of stars taken through a selected filter. Applying this method to the reduction of observations captured through different filters by the 1-m and 2.4-m telescopes at Yunnan Observatory, the results show that the mean of the residuals between observed and computed positions (O-C) after DCR correction is significantly reduced. For our observations taken through an N (null) filter, the median of the mean (O-C) for well-exposed stars (about 15 G-mag) decreases from 19 mas to 3 mas, thus achieving better accuracy, i.e. mean (O-C). Another issue correlated is a systematic error caused by the poor charge transfer efficiency (CTE) when a CCD frame is read out. This systematic error is significant for some of the observations captured by the 1-m telescope at Yunnan Observatory. Using a sigmoidal function to fit and correct the mean (O-C), a systematic error up to 30 mas can be eliminated.
