AI 中文总结
该研究发布SRG/eROSITA全天巡天DR2，含eRASS:3前三次巡天的X射线源星表及对应体分类，拓展了X射线源样本，助力稀有天体发现。
AI 中文摘要
搭载于光谱-伦琴-伽马（SRG）任务上的eROSITA望远镜阵列于2019年12月启动其全天巡天项目，以约6个月的周期对天区进行扫描。在此，我们呈现了从已完成的前三次eROSITA全天巡天（eRASS:3）中得到的点状和延展X射线源的新星表，覆盖银道面西半球，该区域归德国eROSITA联盟所有。我们描述了观测策略、数据处理及分析流水线，并对得到的X射线源总体进行了表征。eRASS:3主星表包含近200万个源，其中包括在0.2-2.3 keV能量波段（eROSITA最敏感的能窗）探测到的1,911,744个点状源和63,796个延展源。该星表的X射线源数量较eRASS1翻倍，提供了不同天体物理类别中X射线辐射天体的全面普查。我们还发布了一个次级硬X射线星表，包含在更硬的2.3-5.0 keV能量波段探测到的近15,000个源。此外，我们发布了六个星表，其中主样本和硬样本各三个，用于识别和分类eRASS:3点状源的光学和红外对应体。该方法实现了对主要为河外X射线辐射体的均匀、高质量识别；例如，我们估计在DESI遗产巡天成像覆盖范围内识别出的140万个对应体中，约88%为河外源。本工作已生成了优化了完备性和纯度的样本，同时拓展了稀有天体的发现空间。SRG/eROSITA全天巡天的第二次数据发布（DR2）仅包含星表，包括本工作中呈现的星表以及更新后的eROSITA上限流量极限服务器。
英文摘要
The eROSITA telescope array on board the Spektrum-Roentgen-Gamma (SRG) mission began its all-sky survey program in December 2019, scanning the sky at an approximately six-month cadence. Here, we present new catalogues of point-like and extended X-ray sources derived from the first three completed eROSITA all-sky surveys (eRASS:3), covering the western Galactic hemisphere, which Germany's eROSITA consortium holds proprietary rights for. We describe the observational strategy, data processing, and analysis pipelines. We also characterise the resulting X-ray source populations. The eRASS:3 main catalogue contains nearly two million sources, including 1,911,744 point-like and 63,796 extended sources, detected in the 0.2-2.3 keV energy band, eROSITA's most sensitive energy window. This volume has doubled the X-ray source content of eRASS1 and provides a comprehensive census of X-ray-emitting objects across diverse astrophysical classes. We also released a secondary hard catalogue of nearly 15,000 sources detected in the harder 2.3-5.0 keV energy band. In addition, we released six catalogues, three for the main sample and three for the hard sample, in which we identify and classify the optical and infrared counterparts of eRASS:3 point-like sources. This approach delivers a homogeneous, high-quality identification of mostly extragalactic X-ray emitters; for example, we estimate that approximately 88% of the 1.4 million counterparts identified within the footprints of the Legacy Survey Imaging for DESI are extragalactic sources. This work has enabled the generation of samples optimised for completeness and purity, while expanding the discovery space for rare populations. The second data release (DR2) of the SRG/eROSITA all-sky survey is a catalogue-only release, comprising the catalogues presented in this work together with an updated version of the eROSITA upper flux limit server.
Comments24 pages, 12 figures. Accepted for publication in A&A. Accompanying eROSITA-DE Data Release 2
