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arXiv 1306.0015astro-ph.CO
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利用地基数据探测团簇内暗条的弱透镜效应

Weak lensing detection of intra-cluster filaments with ground based data

Matteo Maturi, Julian Merten

摘要:

根据目前的宇宙学标准模型,宇宙中的物质沿着一个网状结构排列。这些细丝连接着这个所谓的“宇宙网”的主要节点,这些节点是星系团。虽然它的大尺度分布在数值模拟中得到了明确的表征,但在现实中限制宇宙网络中的暗物质含量是很困难的。最自然的选择是引力透镜。然而,直接检测和映射难以捉摸的细丝信号是具有挑战性的,在这项工作中,我们提出了两种方法,专门为实现这一任务。线性匹配滤波器旨在检测细丝的平滑质量分量,并且被优化以执行剪切分解,该剪切分解遵循透镜化信号的各向异性分量。由于它们的形态学,细丝清楚地继承了这种性质。与此同时,由中心大质量星团产生的污染以自然的方式得到控制。根据滤波器的模板宽度和长度,细丝1 σ检测约为κ ~ 0.01-0.005,使得能够检测其他方法无法达到的结构。第二种方法是补充性的,它试图探测细丝的凝聚成分。该检测是由包围潜在细丝的区域中的子块标识的数量密度确定的,因为它是在用过滤器方法观察到的场中发现的。我们测试了这两种方法对模拟观测的基础上现实的N体模拟的非线性结构,并证明了可行性检测细丝与地面数据。

英文摘要:

According to the current standard model of Cosmology, matter in the Universe arranges itself along a network of filamentary structure. These filaments connect the main nodes of this so-called 'Cosmic Web', which are clusters of galaxies. Although its large-scale distribution is clearly characterized by numerical simulations, constraining the dark matter content of the cosmic web in reality turns out to be difficult. The natural method of choice is gravitational lensing. However, the direct detection and mapping of the elusive filament signal is challenging and in this work we present two methods,specifically tailored to achieve this task. A linear matched filter aims at the detection of the smooth mass component of filaments and is optimized to perform a shear decomposition that follows the anisotropic component of the lensing signal. Filaments clearly inherit this property due to their morphology. At the same time, the contamination arising from the central massive cluster is controlled in a natural way. The filament 1 σ detection is of about κ ~ 0.01-0.005 according to the filter's template width and length, enabling the detection of structures out of reach with other approaches. The second, complementary method seeks to detect the clumpy component of filaments. The detection is determined by the number density of sub-clump identifications in an area enclosing the potential filament, as it was found within the observed field with the filter approach. We test both methods against Mock observations based on realistic N-Body simulations of filamentary structure and prove the feasibility of detecting filaments with ground-based data.

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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