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arXiv 0803.1213astro-ph
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利用暗物质晕分布重建宇宙密度场

Reconstructing the cosmic density field with the distribution of dark matter halos

H. Y. Wang, H. J. Mo, Y. P. Jing, Y. C. Guo, Frank C. van den Bosch, X. H. Yang

摘要:

我们发展了一种新的方法来重建宇宙密度场的分布暗物质晕超过一定的质量阈值。我们的动机是,定义良好的星系群/星系团,这可以用来代表暗晕人口的样本,现在可以从星系的大红移调查中选择,我们的最终目标是使用这些数据来重建在本地宇宙的宇宙密度场。我们的重建方法从一个高于给定质量阈值的暗物质晕样本开始。空间中的每个体积元素根据由晕的维里半径缩放的距离度量被分配到最近的晕的域。利用暗物质晕与其域内质量分布之间的互相关联函数,模拟了给定质量的暗物质晕内及其周围的质量分布。我们使用N体宇宙学模拟表明,在我们的重建方案所需的密度分布可以可靠地确定从大型宇宙学模拟,我们的方法可以准确地重建密度场使用质量下降到$\sim 10^{12}\msun$(以上的星系群的样本可以从当前的大红移星系调查构建)晕。在红移空间中,我们证明了由于晕的特殊速度而引起的红移畸变可以用迭代的方法来校正。我们还描述了我们的方法的一些应用。

英文摘要:

We develop a new method to reconstruct the cosmic density field from the distribution of dark matter haloes above a certain mass threshold. Our motivation is that well-defined samples of galaxy groups/clusters, which can be used to represent the dark halo population, can now be selected from large redshift surveys of galaxies, and our ultimate goal is to use such data to reconstruct the cosmic density field in the local universe. Our reconstruction method starts with a sample of dark matter haloes above a given mass threshold. Each volume element in space is assigned to the domain of the nearest halo according to a distance measure that is scaled by the virial radius of the halo. The distribution of the mass in and around dark matter haloes of a given mass is modelled using the cross-correlation function between dark matter haloes and the mass distribution within their domains. We use N-body cosmological simulations to show that the density profiles required in our reconstruction scheme can be determined reliably from large cosmological simulations, and that our method can reconstruct the density field accurately using haloes with masses down to $\sim 10^{12}\msun$ (above which samples of galaxy groups can be constructed from current large redshift surveys of galaxies). Working in redshift space, we demonstrate that the redshift distortions due to the peculiar velocities of haloes can be corrected in an iterative way. We also describe some applications of our method.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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