论文标题
在Enzo（Foggie）中找出气体和星系。 iii。嘲笑方式：研究观察银河系的偏见介质时的偏见
Figuring Out Gas & Galaxies in Enzo (FOGGIE). III. The Mocky Way: Investigating Biases in Observing the Milky Way's Circumgalactic Medium
论文作者
论文摘要
银河系的环境培养基（CGM）大多被附近的气体在位置 - 速度空间中遮盖，因为我们驻留在银河系内。大多数关于银河系CGM的研究中都存在很大的偏见，该研究集中在易于检测的高速气体上。通过对Foggie模拟的乳白色类似物进行模拟观察，我们研究了与银河系CGM相关的四个观察性偏见。首先，QSO吸收线研究探测了有限量的CGM质量：只有35％的质量处于高银河纬度$ | b |> 20 $度，其中只有一半以$ | v _ {\ rm lsr} | \ rm lsr} | \ gtrsim100 $ km s $ s $ s $ s $ s $^{-1} $移动。其次，当我们从当地的静止标准转到Galaxy的休息框架时，HI 21厘米可观察到的冷气的流入率（$ \ dot {m} $）降低了$ \ sim10 $。同时，凉爽和温暖气体的$ \ dot {m} $不会发生显着变化。第三，OVI和NV有望探测银河系的外部CGM（$ r \ gtrsim $ 15 kpc），但CIV可能不太敏感。最后，如果从内而外观察到CGM而不是从外部视图中观察到CGM，则离子柱密度中的散射是高2倍。我们的工作强调，对银河系CGM的观察，尤其是使用HI 21cm和QSO吸收线的CGM的观察非常有偏见。我们证明，可以通过模拟的乳白色类似物进行合成观察来量化和校准这些偏差。
The circumgalactic medium (CGM) of the Milky Way is mostly obscured by nearby gas in position-velocity space because we reside inside the Galaxy. Substantial biases exist in most studies on the Milky Way's CGM that focus on easier-to-detect high-velocity gas. With mock observations on a Milky-Way analog from the FOGGIE simulation, we investigate four observational biases related to the Milky Way's CGM. First, QSO absorption-line studies probe a limited amount of the CGM mass: only 35% of the mass is at high Galactic latitudes $|b|>20$ degrees, of which only half is moving at $|v_{\rm LSR}|\gtrsim100$ km s$^{-1}$. Second, the inflow rate ($\dot{M}$) of the cold gas observable in HI 21cm is reduced by a factor of $\sim10$ as we switch from the local standard of rest to the galaxy's rest frame; meanwhile $\dot{M}$ of the cool and warm gas does not change significantly. Third, OVI and NV are promising ions to probe the Milky Way's outer CGM ($r\gtrsim$15 kpc), but CIV may be less sensitive. Lastly, the scatter in ion column density is a factor of 2 higher if the CGM is observed from inside-out than from external views because of the gas radial density profile. Our work highlights that observations of the Milky Way's CGM, especially those using HI 21cm and QSO absorption lines, are highly biased. We demonstrate that these biases can be quantified and calibrated through synthetic observations with simulated Milky-Way analogs.
