Understanding Biased Galaxy Formation

了解有偏差的星系形成

• 批准号: 0098584
• 负责人: David Weinberg
• 金额: $ 12.35万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-07-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0098584&HistoricalAwards=false
• 关键词: Understanding; Biased; Galaxy; Formation

AST 0098584WeinbergOver the past two decades astronomers have amassed a considerable body of evidence for the existence of an unseen component of the universe which exerts a gravitational-like influence but has no other identified signature. This component is known as "dark matter." One of the outstanding problems in the construction of cosmological models is our lack of knowledge of just how the dark matter is distributed with respect to the luminous matter. The spatial function which can describe this difference in distribution is referred to as "bias" and its determination is critical for understanding the structure and evolution of the universe. The goal of this project is to construct a series of cosmological models, using a bias model known as the "halo occupation distribution" (HOD) which defines the bias of a population of galaxies by giving the conditional probability p(NjM) that a dark matter halo of virial mass M contains N galaxies, together with prescriptions that specify the relative spatial and velocity distributions of galaxies and dark matter within virialized dark halos. These models would predict different types of galaxy clustering depending on the HOD used. The resulting predicted distributions of galaxies generated by these families of cosmological models will be compared with the observed galaxy distributions found in the upcoming surveys from Australia (the 2dF Galaxy Redshift Survey or "2dFGRS") and from the United States (the Sloan Digital Sky Survey or "SDSS"). These comparisons may confirm the basic validity of the models and thus determine an empirical form of the HOD. Alternatively, these empirical tests may show that the current theoretical picture of galaxy formation is still missing important physical ingredients. Funding for this project was provided by the NSF program for Extragalactic Astronomy & Cosmology (AST/EXC).***

AST 0098584Weinberg 在过去的二十年里，天文学家积累了大量证据，证明宇宙中存在一种看不见的成分，它会产生类似引力的影响，但没有其他可识别的特征。该成分被称为“暗物质”。 构建宇宙学模型的突出问题之一是我们缺乏对暗物质相对于发光物质如何分布的了解。能够描述这种分布差异的空间函数被称为“偏差”，它的确定对于理解宇宙的结构和演化至关重要。该项目的目标是构建一系列宇宙学模型，使用称为“晕占据分布”（HOD）的偏差模型，该模型通过给出维里质量 M 的暗物质晕包含 N 个星系的条件概率 p(NjM) 来定义星系群的偏差，并结合指定维里化暗晕内星系和暗物质的相对空间和速度分布的规定。这些模型将根据所使用的 HOD 来预测不同类型的星系团。这些宇宙学模型家族生成的星系预测分布将与即将进行的澳大利亚巡天（2dF 星系红移巡天或“2dFGRS”）和美国（斯隆数字巡天或“SDSS”）中发现的观测到的星系分布进行比较。这些比较可以确认模型的基本有效性，从而确定 HOD 的经验形式。或者，这些经验测试可能表明，当前星系形成的理论图景仍然缺少重要的物理成分。该项目的资金由 NSF 河外天文学和宇宙学计划 (AST/EXC) 提供。***