完整SDSS DR7中空洞星系的高质量尺寸亏缺
A High-Mass Size Deficit for Void Galaxies in the Complete SDSS DR7
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中文总结 AI 辅助
本研究比较SDSS DR7与TNG300模拟中的空洞星系，发现高质量（M*>10^11太阳质量）空洞星系比场星系紧凑约11%，该尺寸亏缺随欠密度加深而增强，归因于晚期并合在空洞中受抑制，导致其最庞大成员结构至今独特。
中文摘要 AI 辅助
我们通过将斯隆数字巡天数据发布7（Sloan Digital Sky Survey Data Release 7）的NSA星表与同等选择的TNG300样本进行比较，并利用空洞发现算法VoidFinder构建样本，同时通过球形顶帽平滑密度场近似为每个星系分配局部平均欠密度对比度，来刻画环境如何塑造大尺度欠密度区域中星系的尺寸、光度函数和质量函数。空洞星系的特征星等比非空洞对应体更暗，并且在固定恒星质量、红移和颜色下，具有$M_*>10^{11}h^{-1}M_\odot$的NSA空洞星系比场星系紧凑约$11\pm3\\%$，这一亏缺在TNG300模拟中得到了再现。造成这种效应的星系几乎全部是中心星系且主要为早型星系，即那些最有可能通过晚期并合增长其外部包层的系统。这些趋势在$z\leq0.114$的两个红移区间内均成立。至关重要的是，这种亏缺并非空洞样本的固定属性，而是欠密度对比度的陡峭函数，向最空内部加深，并在典型密度处消失，这意味着在进行此类环境依赖性研究时，严格密度控制和样本选择至关重要。相同的环境依赖性也出现在恒星质量函数中，在最深空洞中向较低质量偏移，以及近邻对（即正在进行中的并合）比例中，该比例向最空区域下降。总之，这些结果指向晚期并合驱动的巨星系增长在空洞中受到抑制，使其最庞大成员在结构上至今仍与众不同。
英文摘要
We characterize how environment shapes the sizes, luminosity functions, and mass functions of galaxies in large-scale underdensities by comparing the NSA catalog of the Sloan Digital Sky Survey Data Release 7 with an identically selected TNG300 sample, both built with the void finding algorithm VoidFinder, and by assigning a local average underdensity contrast to each galaxy via a spherical top-hat smoothed density field approximation. Void galaxies have fainter characteristic magnitudes than their non-void counterparts, and, at fixed stellar mass, redshift, and color, NSA void galaxies with $M_*>10^{11}h^{-1}M_\odot$ are about $11\pm3\%$ more compact than galaxies in the field, a deficit the TNG300 simulation reproduces. The galaxies that are responsible for this effect are almost all central and predominantly early type, i.e., the systems that are most likely to grow their outer envelopes via late-time mergers. These trends hold across two redshift bins to $z\leq0.114$. Crucially, this deficit is not a fixed property of the void sample but a steep function of the underdensity contrast, deepening toward the emptiest interiors and washing out at a typical density, implying that strict density control and sample selection are imperative when conducting environmental dependency studies like these. The same environmental dependence appears in the stellar mass function, which shifts to lower masses in the deepest voids, and in the close-pair (i.e., the ongoing merger) fraction, which falls toward the emptiest regions. Together, these point to a late-time, merger-driven growth of massive galaxies that is suppressed in voids, leaving their most massive members structurally distinct today.
发表机构
- The Pennsylvania State University（宾夕法尼亚州立大学）
- Boston University（波士顿大学）
- Adelphi University（阿德菲大学）
- Northeastern University（东北大学）
机构由 AI 辅助整理，请以论文原文为准。
