Predictions for the angular dependence of gas mass flow rate and metallicity in the circumgalactic medium
Predictions for the angular dependence of gas mass flow rate and metallicity in the circumgalactic medium
复制标题
DOI：
10.1093/mnras/staa2888
复制
发表时间：
2020-09
影响因子：
4.8
通讯作者：
C. Péroux;D. Nelson;F. van de Voort-F.-van de Voort-2124733056;A. Pillepich;F. Marinacci;M. Vogelsberger;L. Hernquist
中科院分区：
文献类型：
--
作者：
C. Péroux;D. Nelson;F. van de Voort-F.-van de Voort-2124733056;A. Pillepich;F. Marinacci;M. Vogelsberger;L. Hernquist
我们使用宇宙学流体动力学模拟研究的气体在环星系介质（CGM）的恒星形成星系的角取向的函数的物理性质。我们利用TNG 50的IllustrisTNG项目，以及EAGLE模拟表明，CGM气体的可观察到的属性与方位角，定义为galiocentric角相对于中央星系。这两个模拟是在预测一个强大的调制流率方向与方位角的显着协议：流入是更大的沿着星系长轴，而流出是最强的沿着短轴。对于更高（$\log {（M_\星星/ \rm {M}_\odot）} \sim 10.5$）恒星质量的星系，绝对速率明显更大，与$\log {（M_\星星/ \rm {M}_\odot）}\sim 9.5$天体的$\dot{M} \lesssim 1$ M yr −1 sr−1相比，达到一个数量级。尽管有不同的数值和物理模型，TNG 50和EAGLE预测CGM的平均金属丰度是较高的沿着星系的短轴与长轴。角信号在z < 1的星系恒星质量8.5\lt \log {（M_\星星/ \rm {M}_\odot）} \lt 10.5$的范围内是稳健的。在较大的撞击参数B ≥ 100 kpc时，这种方位角依赖性特别明显。我们的研究结果提出了一个全球性的图片，尽管众多的混合过程中，有一个明确的角度依赖的CGM金属丰度。我们对未来的大型调查项目进行预测，这些项目将能够与这些预期进行比较。事实上，描述CGM气体的运动学，空间分布和金属含量是充分理解星系及其周围环境之间质量，金属和能量交换的关键。
We use cosmological hydrodynamical simulations to examine the physical properties of the gas in the circumgalactic media (CGM) of star-forming galaxies as a function of angular orientation. We utilize TNG50 of the IllustrisTNG project, as well as the EAGLE simulation to show that observable properties of CGM gas correlate with azimuthal angle, defined as the galiocentric angle with respect to the central galaxy. Both simulations are in remarkable agreement in predicting a strong modulation of flow rate direction with azimuthal angle: inflow is more substantial along the galaxy major axis, while outflow is strongest along the minor axis. The absolute rates are noticeably larger for higher ($\log {(M_\star / \rm {M}_\odot)} \sim 10.5$) stellar mass galaxies, up to an order of magnitude compared to $\dot{M} \lesssim 1$ M⊙ yr−1 sr−1 for $\log {(M_\star / \rm {M}_\odot)}\sim 9.5$ objects. Notwithstanding the different numerical and physical models, both TNG50 and EAGLE predict that the average metallicity of the CGM is higher along the minor versus major axes of galaxies. The angular signal is robust across a wide range of galaxy stellar mass $8.5 \lt \log {(M_\star / \rm {M}_\odot)} \lt 10.5$ at z < 1. This azimuthal dependence is particularly clear at larger impact parameters b ≥ 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 programmes that will be able to compare against these expectations. Indeed, characterizing 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.