Origin of weak lensing convergence peaks
Origin of weak lensing convergence peaks
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DOI：
10.1103/physrevd.94.043533
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发表时间：
2016-06
影响因子：
5
通讯作者：
Jia Liu;Zoltan Haiman Princeton University;C. University
中科院分区：
文献类型：
--
作者：
Jia Liu;Zoltan Haiman Princeton University;C. University
弱透镜收敛峰是探测后期非线性结构演化的有前途的工具，提供了二阶统计之外的额外宇宙学信息。先前的理论和观测研究表明，与单独使用后者相比，当峰值计数和二阶统计数据相结合时，${\mathrm{\ensuremath{\Omega}}}_{m}$ 和 ${\ensuremath{\sigma}}_{8}$ 的宇宙学约束最多可提高 $\ensuremath{\approx}2$ 倍。我们使用 $154\text{ }\text{ }{\mathrm{deg}}^{2}$ 加拿大-法国-夏威夷望远镜透镜调查的观测数据研究透镜峰值的起源。我们发现，虽然峰值（高度 $\ensuremath{\kappa}g3.5{\ensuremath{\sigma}}_{\ensuremath{\kappa}}$，其中 ${\ensuremath{\sigma}}_{\ensuremath{\kappa}}$ 是收敛 $\ensuremath{\kappa}}$ 的均方根）通常是由于一个巨大的光环$\ensuremath{\approx}1{0}^{15}{M}_{\ensuremath{\bigodot}}$，低峰 ($\ensuremath{\kappa}\ensuremath{\lesssim}{\ensuremath{\sigma}}_{\ensuremath{\kappa}}$) 与 2\char21{}8 个较小光晕的星座相关($\ensuremath{\lesssim}1{0}^{13}{M}_{\ensuremath{\bigodot}}$)。此外，与高峰相关的光晕的$\ensuremath{\approx}0.25$维里半径相比，负责形成低峰的光晕被发现明显偏离朝向峰中心的视线（影响参数$\ensuremath{\gtrsim}$维里半径），这表明低峰更容易受到重子过程的影响，而重子过程的影响仅限于暗物质晕的内部区域。我们的发现与 Yang 等人的模拟工作结果非常一致。 [物理。修订版 D 84, 043529 (2011)]。
Weak lensing convergence peaks are a promising tool to probe nonlinear structure evolution at late times, providing additional cosmological information beyond second-order statistics. Previous theoretical and observational studies have shown that the cosmological constraints on ${\mathrm{\ensuremath{\Omega}}}_{m}$ and ${\ensuremath{\sigma}}_{8}$ are improved by a factor of up to $\ensuremath{\approx}2$ when peak counts and second-order statistics are combined, compared to using the latter alone. We study the origin of lensing peaks using observational data from the $154\text{ }\text{ }{\mathrm{deg}}^{2}$ Canada-France-Hawaii Telescope Lensing Survey. We found that while high peaks (with height $\ensuremath{\kappa}g3.5{\ensuremath{\sigma}}_{\ensuremath{\kappa}}$, where ${\ensuremath{\sigma}}_{\ensuremath{\kappa}}$ is the rms of the convergence $\ensuremath{\kappa}$) are typically due to one single massive halo of $\ensuremath{\approx}1{0}^{15}{M}_{\ensuremath{\bigodot}}$, low peaks ($\ensuremath{\kappa}\ensuremath{\lesssim}{\ensuremath{\sigma}}_{\ensuremath{\kappa}}$) are associated with constellations of 2\char21{}8 smaller halos ($\ensuremath{\lesssim}1{0}^{13}{M}_{\ensuremath{\bigodot}}$). In addition, halos responsible for forming low peaks are found to be significantly offset from the line of sight towards the peak center (impact parameter $\ensuremath{\gtrsim}$ their virial radii), compared with $\ensuremath{\approx}0.25$ virial radii for halos linked with high peaks, hinting that low peaks are more immune to baryonic processes whose impact is confined to the inner regions of the dark matter halos. Our findings are in good agreement with results from the simulation work by Yang et al. [Phys. Rev. D 84, 043529 (2011)].