AI 中文总结
该研究利用流体动力学风洞模拟，通过改变盘风角度，研究中等质量星系在类似后发座星系团环境中经历冲压压力剥离时冷星际介质的演化，发现冷气体有流出和流入的回落循环，并探讨了回落原因及机制在星系演化不同阶段的重要性。
AI 中文摘要
在环绕大质量宿主星系运行的卫星星系中，冷星际介质（ISM）的演化是其在经历冲压压力剥离（RPS）时演化的重要因素，因为冷分子气体云是最难完全剥离的ISM成分，也是恒星形成的场所。我们使用一组流体动力学风洞模拟来研究ISM的演化，模拟一个中等质量（$M_* = 10^{9.7}$ M$_\odot$）的星系在类似后发座星系团的环境中运行，并改变盘风角度。即使一个遭受冲压压力剥离的星系的最终命运是完全去除气体，我们发现冷气体通过流出和流入（回落）的循环演化。我们表明，在广泛的风角度范围内都可以识别回落，但在接近边缘的角度回落更为明显，并且主要发生在特定象限（尾随侧，旋转进入风中）。大多数流入发生在从未离开延伸至约20 kpc的“内尾”区域的气体中。我们使用简单的理想化模拟讨论回落发生的时间和原因的可能原因。对于高度倾斜的盘，偏移旋转运动是回落的主要驱动因素，而盘阴影和云增长在所有风角度都起作用。最后，我们讨论了每种机制在星系在冲压压力下演化的不同阶段的相对重要性，并将我们的发现与在观测到的RPS星系中检测到的ISM回落实例进行了比较。
英文摘要
The evolution of the cold interstellar medium (ISM) in satellite galaxies orbiting through massive hosts is an important factor in how they evolve while experiencing ram pressure stripping (RPS), as cold molecular gas clouds are the most difficult ISM component to fully strip and serve as the sites of star formation. We investigate ISM evolution using a suite of hydrodynamical wind tunnel simulations with an intermediate mass ($M_* = 10^{9.7}$ M$_\odot$) galaxy orbiting in a Coma cluster-like environment, varying the disk-wind angle. Even if the ultimate fate of a ram pressure stripped galaxy is complete gas removal, we find that cold gas evolves through cycles of outflow and inflow (fallback). We show that fallback can be identified at a wide range of wind angles, but is elevated for angles closer to edge-on and occurs predominantly in a specific quadrant (trailing side, rotating into the wind). Most inflow occurs in gas that never leaves an ``inner tail" region that extends to $\sim20$ kpc. We discuss possible reasons for when and why fallback occurs using simple idealized simulations. For a highly inclined disk, offset rotational motion is a major driver of fallback, while disk shadowing and cloud growth can act at all wind angles. Lastly, we discuss the relative importance of each mechanism at different stages of a galaxy's evolution under ram pressure, and compare our findings with instances of ISM fallback detected in observed RPS galaxies.
Comments26 Pages, 15 Figures
