The Interpretation of Galaxy Clustering

巨大星系样本的成像和光谱调查，最著名的是斯隆数字巡天（SDSS），已经改变了对大尺度结构的研究，但解释的挑战在于，可观测的星系集群既反映了暗物质集群，也反映了星系和暗物质之间潜在的复杂偏差效应。Halo Occupation Distribution （HOD）框架解决了这一挑战，它主要通过特定质量的光晕包含特定类别的特定数量的星系的概率，在被激活的暗物质光晕水平上描述星系偏差。该项目包括理论和观测研究，将进一步发展HOD方法，并将其应用于SDSS的测量。理论工作将揭示环境变化对HOD的影响，例如暗物质晕的星系含量对大尺度密度场的系统依赖。观测工作是对最终SDSS星系红移调查的连贯分析和解释，利用相关函数、群多样性、红移空间扭曲、空洞概率、星系-星系透镜效应、群质量测定和大尺度星系功率谱。这种分析将产生许多不同类型星系的HOD测定结果，以及比传统方法更严格、更易于测试的宇宙学参数约束。它将为星系的形成、暴涨的物理学、宇宙的物质含量以及暗能量的本质提供新的线索。该项目包括一些关于星系团星系透镜效应的工作，作为探测涨落增长和宇宙距离尺度演化的工具。首席研究员担任SDSS的发言人，负责促进SDSS合作的科学互动和生产力，并向天文学界和公众推广SDSS。这项研究为这些活动提供了间接但至关重要的支持，从而提高了SDSS的科学回报及其在教育和公众宣传方面的作用。该项目还支持研究生培训和在各种论坛上公开介绍天文学。

AST-0707985WeinbergImaging and spectroscopic surveys of enormous galaxy samples, most notably the Sloan Digital Sky Survey (SDSS), have transformed the study of large scale structure, but the challenge of interpretation is that observable galaxy clustering reflects both dark matter clustering and the potentially complex bias effect between galaxies and dark matter. The Halo Occupation Distribution (HOD) framework addresses this challenge by describing galaxy bias at the level of virialized dark matter halos, principally via the probability that a halo of a specified mass contains a given number of galaxies of a specified class. This project includes theoretical and observational investigations that will further develop HOD methods and apply them to measurements from the SDSS. The theoretical work will reveal the effect of environmental variations on the HOD, such as a systematic dependence of the galaxy content of dark matter halos on the large scale density field. The observational work is a coherent analysis and interpretation of the final SDSS galaxy redshift survey, drawing on correlation functions, group multiplicities, redshift-space distortions, void probabilities, galaxy-galaxy lensing, group mass determinations, and the large scale galaxy power spectrum. This analysis will yield HOD determinations of many different classes of galaxies, and cosmological parameter constraints that are tighter and better tested than traditionally obtained. It will shed new light on galaxy formation, the physics of inflation, the matter content of the Universe, and the nature of dark energy. The project includes some work on cluster-galaxy lensing as a tool for probing the growth of fluctuations and the evolution of the cosmic distance scale.The Principal Investigator serves as Spokesperson for the SDSS, responsible for fostering the scientific interaction and productivity of the SDSS collaboration and for promoting the SDSS to the astronomical community and the general public. This research provides indirect but crucial support to such activities, thus enhancing the scientific return from the SDSS and its role in education and public outreach. The project also supports graduate student training and the public presentation of astronomy in various forums.