Cluster and Group Environments of Radio Galaxies

遥远的星系团是宇宙学的重要探测器，在揭开星系形成和演化背后的奥秘以及宇宙中大尺度结构的发展方面发挥着关键作用。任何在非常远的距离被确认的星团都会大大增加已知的少数星团。这个项目使用了一种独特的方法来识别新的、遥远的星系团，这个遥远的星系团的样本将有助于确定星系形成的时代，研究随时间变化的星系团的星系群，并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，这些星系的核心拥有超大质量黑洞。吸积的超大质量黑洞会产生射电探测到的喷流和波瓣，这些喷流和波瓣在与周围的星系团内介质(ICM)相互作用时会发生扭曲。这些扭曲有时会导致叶向同一方向弯曲，从而产生广角尾巴(WAT)的形态。在研究低到中等红移的WAT星团环境方面已经奠定了重要的基础。此外，还收集了一个大样本，包括653个水星群，它们的星团环境太暗(因此太遥远)，无法用斯隆数字巡天卫星进行研究。所有这些物体都是用斯皮策在红外线上观察到的。基于较低红移z的星团关联率，该项目的样本预计将在z 0.7发现大约400个新星团。后续的深部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)来实现。根据其选择的性质，所有星系团都将包含射电响亮的活动星系，从而允许研究高红移的活动星系核(AGN)反馈。对于研究活动星系核反馈和约束Sunyaev-Zel‘dovich功率谱模型，红移较高的低质量星团尤为重要。高红移、低质量星系团也是使用其他星系团调查技术最难发现的星系团，这使得这项调查特别有用，因为它将定位具有广泛质量范围的遥远星系团。这个项目的研究成果将被纳入本科课堂。本科生和研究生都将参与该项目的各个方面。首席调查员(PI)将指导本科生和研究生，他们将陪同PI到望远镜观察旅行。国际和平协会将通过参观公共小学和合作科学博物馆展品来吸引社区的参与。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.