Identifying Spatially Offset Active Galactic Nuclei from the Very Large Array Sky Survey: Tracing the Growth of Massive Black Holes in Galaxy Mergers

活动星系核（agn）偏离其宿主星系的中心很可能是星系合并的产物。这样的物体很可能是质量不断增加和增长的大质量黑洞（MBHs）。目前的计划是利用甚大阵巡天（VLASS）对多达1100个这样的天体进行观测。这项调查完成后，将是已知这些天体中最大的样本，也是第一个大而均匀的样本。该团队试图回答有关偏移agn的基本问题，包括它们有多普遍，它们在限制mbh数量方面可能起什么作用，以及它们在mbh的合并驱动增长中可能起什么作用。首席研究员将在亚利桑那州弗拉格斯塔夫的一个社区中心开展一系列外展活动。该项目预计将覆盖300至400名儿童，其中约60%将来自代表性不足的群体。该团队将使用超大阵列巡天（VLASS）的数据来搜索偏移的agn。VLASS是使用Janssky甚大阵列射电天文台在2至4GHz波段对射电天空进行统一调查，覆盖了南纬40度以上的整个天空。对于变异性研究，VLASS分三个时期进行，每个时期由相同的点组成。第一个观测历元（历元1）现在已经完成，现在可以获得历元1图像的来源目录。这项工作将以VLASS Epoch 1目录为基础。该团队将把干净的VLASS源样本与斯隆数字巡天（SDSS）数据发布16 （DR16）中的星系目录进行交叉匹配，这些星系目录与VLASS Epoch 1目录的大约45%重叠。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Active Galactic Nuclei (AGNs) that are offset from the center of their host galaxies are likely the products of galaxy mergers. Such objects are probably massive black holes (MBHs) that are accreting mass and growing. The current program seeks to make observations of up to 1,100 of these objects using the Very Large Array Sky Survey (VLASS). When completed, this survey will be the largest sample of these objects known, and the first large and uniform sample. The team seek to answer fundamental question about offset AGNs, including how common they are, what the role they might have in constraining masses of MBHs, and what role they might have in the merger-driven growth of MBHs. The Principal Investigator will conduct a series of outreaches at a community center in Flagstaff, AZ. This program is expected to reach 300 to 400 children, of whom approximately 60% will be from underrepresented groups.The team will use data from the Very Large Array Sky Survey (VLASS) to search for offset AGNs. VLASS is a uniform survey of the radio sky using the Janssky Very Large Array Radio Observatory in a bandpass of 2 to 4GHz and covers the whole sky above a declination of 40 degrees South. For variability studies, VLASS is being conducted in three epochs, each of which consists of the same pointings. The first epoch of observations (Epoch 1) is now complete, and catalogs of sources from the Epoch 1 images are now available. This work will be based on the VLASS Epoch 1 Catalog. The team will crossmatch the sample of clean VLASS sources with the catalog of galaxies from the Sloan Digital Sky Survey (SDSS) Data Release 16 (DR16) that overlaps with approximately 45% of the VLASS Epoch 1 Catalog.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.