We describe the simulated sky survey underlying the second data challenge (DC2) carried out in preparation for analysis of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) by the LSST Dark Energy Science Collaboration (LSST DESC). Significant connections across multiple science domains will be a hallmark of LSST; the DC2 program represents a unique modeling effort that stresses this interconnectivity in a way that has not been attempted before. This effort encompasses a full end-to-end approach: starting from a large N-body simulation, through setting up LSST-like observations including realistic cadences, through image simulations, and finally processing with Rubin’s LSST Science Pipelines. This last step ensures that we generate data products resembling those to be delivered by the Rubin Observatory as closely as is currently possible. The simulated DC2 sky survey covers six optical bands in a wide-fast-deep area of approximately 300 deg², as well as a deep drilling field of approximately 1 deg². We simulate 5 yr of the planned 10 yr survey. The DC2 sky survey has multiple purposes. First, the LSST DESC working groups can use the data set to develop a range of DESC analysis pipelines to prepare for the advent of actual data. Second, it serves as a realistic test bed for the image processing software under development for LSST by the Rubin Observatory. In particular, simulated data provide a controlled way to investigate certain image-level systematic effects. Finally, the DC2 sky survey enables the exploration of new scientific ideas in both static and time domain cosmology.

我们描述了第二个数据挑战 (DC2) 的模拟天空调查，该调查是为 LSST 暗能量科学合作 (LSST DESC) 对 Vera C. Rubin 天文台遗产时空调查 (LSST) 的分析做准备。跨多个科学领域的重要联系将是 LSST 的标志；DC2 程序代表了一种独特的建模工作，以前所未有的方式强调这种互连性。这项工作包含一个完整的端到端方法：从一个大的N- 身体模拟，通过设置类似 LSST 的观察，包括真实的节奏，通过图像模拟，最后使用 Rubin 的 LSST 科学管道进行处理。最后一步确保我们生成的数据产品与目前由鲁宾天文台提供的数据产品相似。模拟的 DC2 巡天覆盖了大约 300 度²的宽快深区域的六个光学波段，以及大约 1 度²的深钻场。. 我们模拟了计划的 10 年调查中的 5 年。DC2 巡天有多种用途。首先，LSST DESC 工作组可以使用数据集开发一系列 DESC 分析管道，为实际数据的出现做好准备。其次，它可以作为鲁宾天文台正在为 LSST 开发的图像处理软件的现实测试平台。特别是，模拟数据提供了一种受控方式来研究某些图像级系统效应。最后，DC2 巡天可以在静态和时域宇宙学中探索新的科学思想。