发表机构
University of Utah（犹他大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过单元计数统计测试条件色-星等分布（CCMD）模型，发现其对多数子样本的单元计数测量结果拟合良好，明确了星系单元计数变化的成因及对探究星系组装偏差的意义。
AI 中文摘要
条件色-星等分布（CCMD）模型将星系的色-光度分布与暗物质晕质量关联起来，Xu等人通过对斯隆数字巡天（SDSS）的大星系样本在星系颜色和光度的精细分箱下联合建模两点相关函数，已对该模型进行了约束。本研究利用单元计数（CIC）统计，通过将CCMD模型预测与SDSS在不同光度和颜色分箱的16个星系子样本中的测量结果进行比较，测试了星系-晕关联的CCMD模型。此外，我们还将SDSS测量结果与三种CIC分布的解析模型进行了比较。CCMD模型对大多数子样本的SDSS CIC测量结果给出了良好的描述。例外情况是空概率函数以及光度分箱中少数子样本在单元半径为5 Mpc/h时的CIC分布，这些情况也未被解析模型很好地描述。对于这些子样本，一般而言，从SDSS中移除斯隆长城或在CCMD模型中引入速度偏差均无法解决这种不一致。最后，借助CCMD模拟样本，我们研究了星系单元计数变化的原因：对于小单元或平均星系计数较低的单元，其变化反映了物质环境波动和晕占据分布的共同影响；而对于大单元或平均星系计数较高的单元，环境效应占据主导。我们讨论了本研究对探究星系组装偏差的意义。
英文摘要
The conditional colour-magnitude distribution (CCMD) model connects the galaxy colour-luminosity distribution with dark matter halo mass, which has been constrained in Xu et al. by jointly modelling the two-point correlation functions of a large galaxy sample of the Sloan Digital Sky Survey (SDSS) in fine bins of galaxy colour and luminosity. We test the CCMD model of the galaxy-halo connection using counts-in-cells (CIC) statistics by comparing CCMD model predictions with SDSS measurements for 16 subsamples of galaxies in various luminosity and colour bins. In addition, we compare SDSS measurements with three analytic models of CIC distribution. The CCMD model provides a good description of the SDSS CIC measurements for most subsamples. The exceptions are the void probability functions and CIC distributions with cell radius 5 Mpc/h for a few subsamples in the luminous bins, which are not well described by the analytic models, either. For these subsamples, in general, removing the Sloan Great Wall from SDSS or introducing velocity bias to the CCMD model does not resolve the disagreement. Finally, with the help of the CCMD mocks, we investigate the cause of the variations of the galaxy counts in cells. For small cells or cells with a low mean galaxy count, the variation reflects effects from fluctuations in both the matter environment and the halo occupation distribution, while for large cells or cells with a high mean galaxy count, the environment effect dominates. We discuss the implications of our work for investigating galaxy assembly bias.
