The Interpretation of Galaxy Clustering

AST-0707985对巨大的星系样本进行的Weinberg成像和光谱测量，最著名的是斯隆数字巡天(SDSS)，改变了大尺度结构的研究，但解释的挑战是，可观测到的星系团既反映了暗物质聚集，也反映了星系和暗物质之间潜在的复杂偏差效应。晕占据分布(HOD)框架通过在维里化暗物质晕的水平上描述星系偏差来解决这一挑战，主要是通过指定质量的晕包含指定类别的给定数量的星系的概率来描述。该项目包括理论和观测调查，这些调查将进一步发展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，例如暗物质晕星系内容对大尺度密度场的系统依赖。观测工作是对最终的SDSS星系红移调查进行连贯的分析和解释，利用了相关函数、群多重数、红移空间扭曲、空洞概率、星系-星系透镜、群质量测定和大尺度星系功率谱。这一分析将产生许多不同类别星系的HOD测定，以及比传统获得的更严格和更好测试的宇宙学参数约束。它将为星系的形成、膨胀的物理学、宇宙的物质含量和暗能量的性质带来新的曙光。该项目包括一些关于星系团-星系透镜的工作，以此作为探索涨落增长和宇宙距离尺度演变的工具。首席调查员是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。这项研究为这类活动提供了间接但至关重要的支持，从而加强了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.