The cosmic web of the Local Universe: cosmic variance, matter content and its relation to galaxy morphology
The cosmic web of the Local Universe: cosmic variance, matter content and its relation to galaxy morphology
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DOI：
10.1093/mnras/stu1746
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发表时间：
2014-06
影响因子：
4.8
通讯作者：
S. E. Nuza;F. Kitaura;S. Hess;N. Libeskind;V. Mueller
中科院分区：
文献类型：
--
作者：
S. E. Nuza;F. Kitaura;S. Hess;N. Libeskind;V. Mueller
我们提出，第一次，一个本地宇宙（LU）的表征使用高精度约束$N $体模拟的基础上自洽相空间重建的大尺度结构的2微米全天星系红移调查。我们分析我们是否生活在一个特殊的宇宙网络环境中，通过估计宇宙方差从一组无约束的$\Lambda $CDM模拟作为一个函数的距离随机观察员。通过计算空隙、片、丝和结的体积和质量填充分数，我们发现LU在尺度$r> 15\，h ^{-1}\，{\rm Mpc}$上显示出约$1\sigma $的典型分散，与$\Lambda $CDM一致，当考虑约$60\，h ^{-1}\，{\rm Mpc}$半径的球体时，收敛到公平无偏样本。此外，我们计算了LU的物质密度分布，并发现只有在考虑暗晕的贡献时，才与Karachentsev（2012）的估计值合理一致。这表明观测估计值可能偏向于低密度值。作为我们重建的第一个应用程序，我们调查了不同星系形态类型居住在某些宇宙网络环境中的可能性。特别是，我们发现，无论用于定义网络的方法，无论是基于密度或特有的速度场，椭圆星系表现出明显的倾向，优先居住在集群，而不是空洞（分别高达5.3西格玛和9.8西格玛的水平），相反，对于螺旋星系（分别高达5.6西格玛和5.4西格玛的水平）。这些研究结果与以前的作品是兼容的，虽然在更高的置信水平。
We present, for the first time, a Local Universe (LU) characterization using high precision constrained $N$-body simulations based on self-consistent phase-space reconstructions of the large-scale structure in the Two-Micron All-Sky Galaxy Redshift Survey. We analyse whether we live in a special cosmic web environment by estimating cosmic variance from a set of unconstrained $\Lambda$CDM simulations as a function of distance to random observers. By computing volume and mass filling fractions for voids, sheets, filaments and knots, we find that the LU displays a typical scatter of about $1\sigma$ at scales $r>15\,h^{-1}\,{\rm Mpc}$, in agreement with $\Lambda$CDM, converging to a fair unbiased sample when considering spheres of about $60\,h^{-1}\,{\rm Mpc}$ radius. Additionally, we compute the matter density profile of the LU and found a reasonable agreement with the estimates of Karachentsev (2012) only when considering the contribution of dark haloes. This indicates that observational estimates may be biased towards low density values. As a first application of our reconstruction, we investigate the likelihood of different galaxy morphological types to inhabit certain cosmic web environments. In particular, we find that, irrespective of the method used to define the web, either based on the density or the peculiar velocity field, elliptical galaxies show a clear tendency to preferentially reside in clusters as opposed to voids (up to a level of $5.3\sigma$ and $9.8\sigma$ respectively) and conversely for spiral galaxies (up to a level of $5.6\sigma$ and $5.4\sigma$ respectively). These findings are compatible with previous works, albeit at higher confidence levels.