标题： LSST DP1中X射线源的光学对应物 显示英文标题

标题： Optical Counterparts to X-ray sources in LSST DP1

摘要： 我们提出了一种X射线源综合目录与维拉·C·鲁宾天文台数据预览1 (DP1)之间的交叉匹配，以识别光学对应体。作为DP1一部分的目标六个领域包括扩展钱德拉深空场南（E-CDF-S）、欧几里得深空场南（EDF-S）、福纳克斯矮椭圆星系（Fornax dSph）、47人马座（47 Tuc）以及低银河和黄道纬度的科学验证场（SV_95_-25和SV_38_7）。我们找到了3830个X射线源中的2314个匹配项。我们还将我们的交叉匹配与E-CDF-S区域的DP1之前的尝试进行了比较，以识别光学对应体。偶然匹配的概率在每个DP1领域中有所不同，在E-CDF-S领域总体可靠性较高，而在其他领域高可靠性匹配的比例较低。我们检测到的大多数已知源，不出所料，是活动星系。我们绘制了X射线与光学通量比值与光学绝对星等和颜色的关系，试图使用转换为LSST{\em Gaia}的颜色阈值$g$-$i$来识别银河系中的吸积致密天体，但未在这些主要河外对应体中找到任何强有力的候选者。DP1数据集包含在多个夜晚收集的高时间分辨率测光数据。我们在假设X射线对应体倾向于表现出更高光学变异性的情况下，为每个对象计算了Stetson\( J \)变异性指数；然而，与场天体相比，我们的样本在DP1时间尺度上是否更具变异性，证据尚不明确。 显示英文摘要

摘要： We present a crossmatch between a combined catalog of X-ray sources and the Vera C. Rubin Observatory Data Preview 1 (DP1) to identify optical counterparts. The six fields targeted as part of DP1 include the Extended Chandra Deep Field South (E-CDF-S), the Euclid Deep Field South (EDF-S), the Fornax Dwarf Spheroidal Galaxy (Fornax dSph), 47 Tucanae (47 Tuc) and science validation fields with low galactic and ecliptic latitude (SV\_95\_-25 and SV\_38\_7, respectively). We find matches to 2314 of 3830 X-ray sources. We also compare our crossmatch to DP1 in the E-CDF-S field to previous efforts to identify optical counterparts. The probability of a chance coincidence match varies across each DP1 field, with overall high reliability in the E-CDF-S field, and lower proportion of high-reliability matches in the other fields. The majority of previously known sources that we detect are, unsurprisingly, active galaxies. We plot the X-ray-to-optical flux ratio against optical magnitude and color in an effort to identify Galactic accreting compact objects using a {\em Gaia} color threshold transformed to LSST $g$--$i$, but do not find any strong candidates in these primarily extragalactic counterparts. The DP1 dataset contains high-cadence photometry collected over a number of nights. We calculate the Stetson \( J \) variability index for each object under the hypothesis that X-ray counterparts tend to exhibit higher optical variability; however, the evidence is inconclusive whether our sample is more variable over DP1 timescales when compared to field objects.