论文标题
使用lyman-$α$ forest层析成像限制波动的gunn-peterson近似，$ z = 2 $
Constraining the Fluctuating Gunn-Peterson Approximation Using Lyman-$α$ Forest Tomography at $z=2$
论文作者
论文摘要
波动的Gunn-Peterson近似（FGPA）是一种常用的方法，可以在宇宙中午（$ z \ gtrsim 2 $）中生成模拟Lyman-$ $ $ $α$（LY $α$）的森林吸收串，从$ N $ n $模拟的情况下，而无需运行昂贵的水力动态模拟。由3D IGM断层扫描观测值的最新发展以及物质密度电场重建技术应用于$ z \ sim 2 $的Galaxy Redshift样品，我们研究了通过直接检查观察性测试FGPA的可能性，通过直接检查LY $α$传输与下层物质密度密度之间的关系。具体而言，我们分析了使用不同的代码和子网格模型运行的Eagle，Illustris，Illustristng和Nyx宇宙流体动力学模拟。虽然FGPA是对低密度区域中IgM的出色描述，但在较高密度下的传输密度分布的斜率受到反馈过程的显着影响，从而导致FGPA破坏该状态。即使没有增加的反馈，我们也会发现由非线性结构生长引起的流体动力学效应引起的显着偏差。然后，假设最近的Clamato调查的视线采样和频谱特性，我们开始使用逼真的模拟数据进行比较，并发现与当前数据集之间的识别和流体动力学模型之间的识别是一项挑战。但是，从未来极大的望远镜或多重光谱调查（例如Subaru PFS）中改进的视线采样应允许对FGPA进行严格的测试，并可以检测到Galaxy反馈对IGM的影响。
The fluctuating Gunn-Peterson approximation (FGPA) is a commonly-used method to generate mock Lyman-$α$ (Ly$α$) forest absorption skewers at Cosmic Noon ($z\gtrsim 2$) from the matter-density field of $N$-body simulations without running expensive hydrodynamical simulations. Motivated by recent developments in 3D IGM tomography observations as well as matter density field reconstruction techniques applied to galaxy redshift samples at $z\sim 2$, we examine the possibility of observationally testing FGPA by directly examining the relationship between the Ly$α$ transmission and the underlying matter density field. Specifically, we analyze the EAGLE, Illustris, IllustrisTNG and Nyx cosmological hydrodynamic simulations, that were run with different codes and sub-grid models. While the FGPA is an excellent description of the IGM in lower-density regions, the slope of the transmission-density distribution at higher densities is significantly affected by feedback processes causing the FGPA to break down in that regime. Even without added feedback, we find significant deviations caused by hydrodynamical effects arising from non-linear structure growth. We then proceed to make comparisons using realistic mock data assuming the sightline sampling and spectral properties of the recent CLAMATO survey, and find that it would be challenging to discern between the FGPA and hydrodynamical models with current data sets. However, the improved sightline sampling from future extremely large telescopes or large volumes from multiplexed spectroscopic surveys such as Subaru PFS should allow for stringent tests of the FGPA, and make it possible to detect the effect of galaxy feedback on the IGM.
