Investigations of a Statistically Complete Sample of Galaxy Clusters

最近完成的由ROSAT卫星进行的X射线全天探测可以提供星系团的样本，这些星系团既有很好的量化选择标准，又位于天空的毗连区域。为了获得这一样本，有必要从更多的其他来源中确定集群。首席调查员只是少数几位受邀参加ROSAT调查的美国天文学家之一，并在发布之前很久就获得了这一X射线数据。这笔赠款将为星系团样品的后续光学研究提供支持，特别强调对星系团的初步鉴定，以及后来对X射线和光学性质、大尺度结构和经典星等-红移关系的演化的研究。对ROSAT数据的分析将使以前的研究有重大改进。

The recently completed X-ray all-sky survey carried out by the ROSAT satellite can provide a sample of clusters of galaxies which has both well established quantifiable selection criteria and is in a contiguous region of the sky. To obtain this sample it is necessary to identify the clusters from the more numerous other sources. The Principal Investigator is only one of a few US astronomers who were invited to participate in the ROSAT survey and has access to this X-ray data well in advance of publication. This grant will provide support for follow-up optical studies of the cluster sample with particular emphasis on the initial identification of the clusters and later investigations of evolution of X-ray and optical properties, large scale structure, and the classical magnitude-redshift relation. Analysis of the ROSAT data will enable significant improvements over previous studies to be made.