Collaborative Research: Understanding the Physics of Galaxy Clustering on Small Scales

这个项目将在10千秒差距到1百万秒差距的尺度上测量、建模和解释星系集群——这是宇宙学背景下的小尺度。该项目包括四个主要的科学目标。(1)约束局部宇宙中暗物质晕内星系的空间分布。利用斯隆数字巡天（SDSS）的红移数据，提议团队将测量投影的两点相关函数、角相关函数以及星系群和星系团的表面密度剖面。他们将利用解析模型和从宇宙n体模拟中构建的数值模型，对这些统计数据进行建模，以约束暗晕中星系的密度分布。(2)利用新的重子振荡光谱调查（BOSS）的数据，将上述分析扩展到更高的红移。对相关函数的建模将揭示晕内星系空间分布的最新演变。(3)完善了提出的暗物质亚晕在合并影响下演化的半解析模型，改进了质量损失的解析公式，并纳入了重子物质的作用。(4)通过将改进的光晕模型与星团统计数据进行比较，约束较大光晕合并星系的恒星形成和恒星剥离效率。该项目将支持两所合作院校的几名研究生和本科生的工作。此外，该项目将为夏季K-12科学营提供资金，以便田纳西州纳什维尔地区的少数民族学生能够在没有经济负担的情况下参加。

This project will measure, model, and interpret the clustering of galaxies on scales of 10 kiloparsecs to 1 megaparsec -- small scales in the cosmological context. The project consists of four main science goals. (1) Constrain the spatial distribution of galaxies inside dark matter halos in the local universe. Using redshift data from the Sloan Digital Sky Survey (SDSS), the proposing team will measure the projected two-point correlation function, the angular correlation function, and the surface density profile of galaxies in groups and clusters. They will model these statistics to constrain the density profile of galaxies in dark halos, using both analytic models and numerical models constructed from cosmological N-body simulations. (2) Extend the above analysis to higher redshift by using data from the new Baryon Oscillation Spectroscopic Survey (BOSS). Modeling the correlation functions will reveal the recent evolution in the spatial distribution of galaxies within halos. (3) Refine the proposers' semi-analytic model for the evolution of dark matter subhalos under the influence of merging, improving the analytic prescription for mass loss and including the role of baryonic matter. (4) By comparing the improved halo model to the clustering statistics, constrain the star formation and star stripping efficiencies for galaxies merging with larger halos. The project will support the work of several graduate and undergraduate students at the two collaborating institutions. In addition, the project will provide funding for summer K-12 science camps so that minority students in the Nashville, TN area will be able to attend without financial burden.