Cluster and Group Environments of Radio Galaxies

遥远星系团是宇宙学的重要探测器，是揭开星系形成和演化以及宇宙大尺度结构发展背后奥秘的关键角色。 任何在非常远的距离被证实的星团都大大增加了已知的少数星团。 该项目采用了一种独特的方法来识别新的、遥远的星系团，这一遥远星系团的样本将有助于确定星系形成的时代，研究星系团随时间的星系数量，以及限制包括暗能量在内的宇宙学模型。星系团通常在其中心附近包含明亮的椭圆星系，这些星系的核心有超大质量黑洞。 吸积超大质量黑洞产生喷流和波瓣，在射电中被探测到，这些喷流和波瓣在与周围的团内介质（ICM）相互作用时变得扭曲。 这些扭曲有时会导致波瓣向同一方向弯曲，从而形成广角尾（WAT）形态。 重要的基础已经奠定了在研究的集群环境的低到中等红移的瓦特。 此外，一个大样本的653瓦特与集群环境太暗（因此遥远），以研究与斯隆数字巡天已经组装。 所有这些物体都是用斯皮策在红外线上观察到的。 基于在较低红移z处的星系团关联率，该项目的样本预计将揭示约400个z 0.7的新星系团。 后续深度光学成像是调查的下一步，将使用4.3米的发现频道望远镜（DCT）实现。 根据它们的选择性质，所有的星系团都将包含射电大声的活动星系，从而可以在高红移下研究活动星系核（AGN）的反馈。 高红移的低质量星系团对于研究活动星系核反馈和Sunyaev-Zel'dovich功率谱的约束模型特别重要。 高红移、低质量星系团也是最难用其他星系团调查技术发现的星系团，因此这项调查特别有用，因为它将定位具有广泛质量的遥远星系团。本项目的研究成果将包括在本科课程中。 本科生和研究生水平的学生将参与该项目的各个方面。 首席研究员（PI）将指导本科生和研究生，他们将陪同PI前往望远镜进行观察。 PI将通过公立小学访问和科学博物馆展览的合作参与社区。 学生和PI将参与探索频道的公共宣传活动，包括电影和在线科学报道。

Distant clusters of galaxies are important probes of cosmology and are key players in unraveling the mysteries behind galaxy formation and evolution and the development of large scale structure in the Universe. Any clusters that are confirmed at very great distances add significantly to the few that are known. This project employs a unique method for identifying new, distant clusters of galaxies, and this sample of distant galaxy clusters will help in determining the epoch of galaxy formation, in studying the galaxy populations of clusters over time, and in constraining cosmological models including dark energy. Clusters usually contain bright elliptical galaxies near their centers, and these galaxies host supermassive black holes in their cores. Accreting supermassive black holes produce jets and lobes detected in the radio, and these jets and lobes become distorted as they interact with the surrounding intracluster medium (ICM). These distortions sometimes result in the lobes being bent in the same direction, resulting in a wide-angle tail (WAT) morphology. Significant groundwork has been laid in studying the cluster environments of WATs at low-to-moderate redshifts. In addition, a large sample of 653 WATs with cluster environments too faint (and therefore distant) to be studied with the Sloan Digital Sky Survey has been assembled. All of these objects are being observed in the infrared with Spitzer. Based on cluster association rates at lower redshift z, this project's sample is expected to reveal approximately 400 new clusters at z 0.7. Follow-up deep optical imaging is the next step in the survey and will be achieved using the 4.3-meter Discovery Channel Telescope (DCT). By the nature of their selection, all the clusters will contain radio-loud active galaxies, allowing the study of active-galactic nucleus (AGN) feedback at high redshift. Poor, low-mass clusters at high redshifts are particularly important for studying AGN feedback and for constraining models of the Sunyaev-Zel'dovich power spectrum. High-redshift, low-mass clusters are also the most difficult ones to find using other cluster survey techniques, making this survey particularly useful because it will locate distant clusters with a wide range of masses.Research results of this project will be included in undergraduate classes. Students at both the undergraduate and graduate levels will be involved with all aspects of the project. The Principal Investigator (PI) will mentor undergraduate and graduate students, who will accompany the PI on observing trips to the telescope. The PI will engage the community through public elementary school visits and collaboration on science museum exhibits. Students and the PI will participate with public outreach efforts with the Discovery Channel, including films and online science reporting.