标题： 盘星系翘曲现象与TNG50：银河系和M31相似星系的多样性 显示英文标题

标题： Disk flaring with TNG50: diversity across Milky Way and M31 analogs

摘要： 我们使用 TNG50 模拟中的 198 个银河系（MW）和仙女座（M31）矮星系样本，量化了现代高分辨率宇宙学流体力学模拟所预测的盘状星系翘曲程度。盘状星系翘曲是指随着星系中心距离的增加，恒星盘垂直高度的增大。TNG50 星系被选为具有恒星盘形态，恒星质量范围在$M_* = 10^{10.5 - 11.2}~\rm{M_{\odot}}$，并且在$z=0$处具有类似 MW 的百万秒差距尺度环境。这些 TNG50 MW/M31 类似物的恒星盘展示了广泛的结构特性多样性，包括一些盘尺度长度和薄厚盘尺度高度与银河系和仙女座测量或推断出的相当的星系。使用一组物理成分，TNG50 对于单年龄恒星群体也返回了多种多样的翘曲味道和数量。因此，本文提出了一种非参数化的翘曲特征描述方法。典型的 MW/M31 类似物在外盘区域的盘高度比内盘区域的大 $1.5-2$倍，但对于老年和年轻恒星群体均如此，但存在较大的星系间变化。哪类恒星群体翘曲更多以及翘曲的程度也因星系而异。TNG50 实际上涵盖了现有银河系观测限制和所有先前数值发现。翘曲量与$z=0$全局星系结构属性或合并历史之间的联系很复杂。然而，尺度高度与局部恒星垂直运动学和引力势之间的联系显然是存在的。 显示英文摘要

摘要： We use the sample of 198 Milky Way (MW) and Andromeda (M31) analogs from TNG50 to quantify the level of disk flaring predicted by a modern, high-resolution cosmological hydrodynamical simulation. Disk flaring refers to the increase of vertical stellar disk height with galactocentric distance. The TNG50 galaxies are selected to have stellar disky morphology, a stellar mass in the range of $M_* = 10^{10.5 - 11.2}~\rm{M_{\odot}}$, and a MW-like Mpc-scale environment at $z=0$. The stellar disks of such TNG50 MW/M31 analogs exhibit a wide diversity of structural properties, including a number of galaxies with disk scalelength and thin and thick disk scaleheights that are comparable to those measured or inferred for the Galaxy and Andromeda. With one set of physical ingredients, TNG50 returns a large variety of flaring flavours and amounts, also for mono-age stellar populations. With this paper, we hence propose a non-parametric characterization of flaring. The typical MW/M31 analogs exhibit disk scaleheights that are $1.5-2$ times larger in the outer than in the inner regions of the disk for both old and young stellar populations, but with a large galaxy-to-galaxy variation. Which stellar population flares more, and by how much, also varies from galaxy to galaxy. TNG50 de facto brackets existing observational constraints for the Galaxy and all previous numerical findings. A link between the amount of flaring and the $z=0$ global galaxy structural properties or merger history is complex. However, a connection between the scaleheights and the local stellar vertical kinematics and gravitational potential is clearly in place.