Constraining Bias via Clustering in Galaxy Surveys

通过星系调查中的聚类来限制偏差

• 批准号: 0206243
• 负责人: Istvan Szapudi
• 金额: $ 25.88万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0206243&HistoricalAwards=false
• 关键词: Constraining; Bias; via; Clustering; Galaxy

AST 0206243SzapudiCurrent cosmological theories imply that the stars, galaxies and clusters of galaxies that we can see represent only a relatively small fraction of the matter content of the universe. Most of the matter is in a form unknown to us, and can be detected only through its gravitational pull. The nature of this ``Dark Matter'' is the single most interesting problem in contemporary theoretical physics, and its study involves the amalgamation of information from different disciplines, such as particle physics, astronomy, and cosmology. The present project aims to constrain the properties of this elusive dark matter by looking at ``bias'', the difference between the statistical properties of visible and dark matter.According to current theories of structure formation, small initial fluctuations in the early Universe grew under the influence of gravity until the large-scale structures which, we see at the present day, formed. It appears that galaxies formed where the underlying dark matter concentrated in clumps (called halos). Thus, the present distribution of galaxies depends both on the distribution of dark matter and on the efficiency with which dark matter halos turn into galaxies. Novel statistical measures developed by Dr. Szapudi and his collaborators will be used to characterize the present-day distribution of galaxies using data from on-going wide field surveys (e.g., the Sloan Digital Sky Survey) which encompass up to a million objects. Then the theory of bias will be applied to these measured distributions to constrain the distribution of the underlying dark matter. This distribution, in turn can be used to test predictions from the various phenomenological and fundamental theories which have been developed to describe the "Dark Matter".***

AST 0206243Szapudi 当前的宇宙学理论表明，我们所看到的恒星、星系和星系团仅代表宇宙物质含量的相对较小的一部分。大多数物质的形式是我们未知的，只能通过其引力来探测。这种“暗物质”的本质是当代理论物理学中最有趣的问题，其研究涉及来自不同学科的信息的融合，例如粒子物理学、天文学和宇宙学。目前的项目旨在通过观察“偏差”（可见物质和暗物质的统计特性之间的差异）来限制这种难以捉摸的暗物质的特性。根据当前的结构形成理论，早期宇宙的微小初始波动在重力的影响下不断增长，直到我们今天看到的大规模结构形成。星系似乎是在底层暗物质集中成团（称为晕）的地方形成的。因此，目前星系的分布既取决于暗物质的分布，也取决于暗物质晕变成星系的效率。 Szapudi 博士和他的合作者开发的新颖统计方法将用于利用正在进行的广域巡天（例如斯隆数字巡天）的数据来描述当前星系的分布，这些巡天观测涵盖了多达一百万个天体。然后，偏差理论将应用于这些测量的分布，以约束潜在暗物质的分布。这种分布反过来可用于测试各种现象学和基础理论的预测，这些理论是为描述“暗物质”而开发的。***