We use cosmological hydrodynamical simulations to examine the physical properties of the gas in the circumgalactic media (CGM) of star-forming galaxies as a function of angular orientation. We utilise TNG50 of the IllustrisTNG project, as well as the EAGLE simulation to show that observable properties of CGM gas correlate with azimuthal angle, defined as the galiocentric angle with respect to the central galaxy. Both simulations are in remarkable agreement in predicting a strong modulation of flow rate direction with azimuthal angle: inflow is more substantial along the galaxy major axis, while outflow is strongest along the minor axis. The absolute rates are noticeably larger for higher (log(M_* / M_sun) ~ 10.5) stellar mass galaxies, up to an order of magnitude compared to M^dot 100 kpc. Our results present a global picture whereby, despite the numerous mixing processes, there is a clear angular dependence of the CGM metallicity. We make forecasts for future large survey programs that will be able to compare against these expectations. Indeed, characterising the kinematics, spatial distribution and metal content of CGM gas is key to a full understanding of the exchange of mass, metals, and energy between galaxies and their surrounding environments.

中文翻译：

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环流介质中气体质量流量和金属度的角相关性预测

我们使用宇宙学流体动力学模拟来检查恒星形成星系的环绕星系介质 (CGM) 中气体的物理特性作为角方向的函数。我们利用 IllustrisTNG 项目的 TNG50 以及 EAGLE 模拟来表明 CGM 气体的可观察特性与方位角相关，方位角定义为相对于中央星系的伽利略角。两种模拟在预测流速方向与方位角的强烈调制方面都非常一致：沿星系长轴的流入量更大，而沿短轴的流出量最强。对于更高 (log(M_* / M_sun) ~ 10.5) 恒星质量的星系，绝对速率明显更大，与 M^dot 100 kpc 相比高达一个数量级。我们的结果展示了一幅全球图景，尽管有许多混合过程，但 CGM 金属丰度有明显的角度依赖性。我们对未来的大型调查项目进行预测，这些项目将能够与这些预期进行比较。事实上，表征 CGM 气体的运动学、空间分布和金属含量是全面了解星系与其周围环境之间质量、金属和能量交换的关键。