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

偏离所在星系中心的活动星系核(AGN)很可能是星系合并的产物。这样的天体可能是质量不断增大的大质量黑洞(MBH)。目前的计划寻求使用甚大阵列巡天(VLASS)对多达1100个这样的天体进行观测。完成后，这次调查将是已知的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抵消AGN的基本问题，包括它们有多常见，它们在限制MBH数量方面可能扮演什么角色，以及它们在合并驱动的MBH增长中可能扮演什么角色。首席调查员将在亚利桑那州弗拉格斯塔夫的一个社区中心进行一系列外展。这项计划预计将惠及300至400名儿童，其中约60%将来自代表性不足的群体。该团队将使用甚大阵列天空调查(VLASS)的数据来搜索偏移活动星系核。Vlass是使用Janssky甚大阵列射电天文台在2到4 GHz的带通范围内对射电天空进行的统一测量，覆盖了南纬40度以上的整个天空。对于变异性研究，Vlass是在三个时期进行的，每个时期都由相同的点组成。第一个观测纪元(纪元1)现已完成，来自纪元1号图像的来源目录现已可用。这项工作将以Vlass Epoch 1目录为基础。该团队将把清洁的Vlass源样本与斯隆数字天空勘测(SDSS)数据发布16(DR16)中的星系目录进行交叉匹配，该星表与Vlass Epoch 1星表的大约45%重叠。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.