AI 中文总结
该研究基于FOGGIE模拟，探究投影、分辨率等因素对发射加权投影速度结构函数测量CGM湍流驱动尺度的影响，为相关观测解释提供依据。
AI 中文摘要
星系的星系际介质（CGM）的线发射的空间分辨运动学可包含CGM湍流的信息，而湍流可能在星系演化中发挥重要作用。由于该区域的弥散特性，对低红移CGM发射的观测一直有限，直到近期研究利用空间分辨发射线运动学探测CGM湍流。我们利用速度结构函数（VSF）作为湍流性质的测量指标，基于高分辨率宇宙学 zoom-in FOGGIE 模拟开展研究。我们重点关注VSF斜率的“转折”位置，该位置常被用于测量湍流驱动尺度，并研究分辨率、测量区域大小、投影效应和气体温度对推断的CGM湍流驱动尺度的影响。研究发现，投影会显著降低VSF的归一化值，但三维VSF与发射加权二维VSF之间的斜率无显著差异；测量VSF所用区域的大小（可视为给定仪器灵敏度下发射星云的大小）与VSF的转折位置直接相关。当利用VSF从发射数据解释CGM湍流时，必须考虑这些依赖关系，因为投影、分辨率、灵敏度限制以及所探测气体的温度都会对VSF结构和相应推断的湍流性质产生可测量的影响。
英文摘要
The spatially-resolved kinematics of line emission from the circumgalactic medium (CGM) of a galaxy can contain information about the CGM turbulence, which may play an important role in galaxy evolution. Due to the region's diffuse nature, there have been limited observations of low-redshift CGM emission until recent efforts that use spatially-resolved emission line kinematics to probe CGM turbulence. We use velocity structure functions (VSFs) as a measure for the properties of turbulence using the high-resolution cosmological zoom-in FOGGIE simulations. We focus on the location of the "turnover" in the VSF slope, often used as a measurement of the turbulence driving scale, and study how resolution, measurement area size, projection effects, and gas temperature influence the inferred CGM turbulence driving scale. We find that projection significantly lowers the VSF normalization but we do not find significant differences in the slope between 3D VSFs and emission-weighted projected 2D VSFs. We find that the size of the area used to measure the VSF, which can be thought of as the size of the emission nebula for a given instrument sensitivity, correlates directly with the turnover location in the VSF. These dependencies should be considered when using VSFs to interpret CGM turbulence from emission data, as projection, resolution and sensitivity constraints, and the temperature of the gas probed will all have a measurable effect on the VSF structure and the corresponding inferred turbulent properties.
Comments25 pages, 17 figures, submitted to ApJ
