论文标题
在插图模拟中仙女座类似物的不对称漂移
Asymmetric Drift of Andromeda Analogs in the IllustrisTNG Simulation
论文作者
论文摘要
我们分析了来自Illustristng宇宙学模拟的仙女座（M31）质量类似物的恒星年龄的函数。我们将恒星颗粒分为四个年龄组：小于1 Gyr，1至5 Gyr，5至10 Gyr和更大的GYR，并比较这些组的运动学与中性气体的运动学。我们计算从质量中心从2 kpc到20 kpc的每个类似物的恒星和气体成分的旋转曲线。我们发现气体旋转曲线和恒星旋转曲线之间的滞后或不对称漂移（AD）平均随着恒星年龄而增加。这一发现与仙女座星系磁盘中AD的观察测量结果一致。当M31类似物根据合并历史记录分为组时，我们发现与未在同一时间范围内没有4：1合并的类似物相比，最后4 Gyr，8 Gyr或12 Gyr的类似物的AD差异是差异。在最后4个GYR中有4：1合并的类似物的子集也类似于M31磁盘中恒星的AD测量值，提供了证据，表明M31实际上可能最近与银河系合并了近四分之一的质量。需要在模拟中使用高分辨率缩放的进一步工作，以探索内部供暖对AD的贡献。
We analyze the kinematics as a function of stellar age for Andromeda (M31) mass analogs from the IllustrisTNG cosmological simulation. We divide the star particles into four age groups: less than 1 Gyr, 1 to 5 Gyr, 5 to 10 Gyr, and greater 10 Gyr, and compare the kinematics of these groups to that of the neutral gas cells. We calculate rotation curves for the stellar and gaseous components of each analog from 2 kpc to 20 kpc from the center of mass. We find that the lag, or asymmetric drift (AD), between the gas rotation curve and the stellar rotation curve on average increases with stellar age. This finding is consistent with observational measurements of AD in the disk of the Andromeda galaxy. When the M31 analogs are separated into groups based on merger history, we find that there is a difference in the AD of the analogs that have had a 4:1 merger the last 4 Gyr, 8 Gyr, or 12 Gyr compared to analogs that have not experienced a 4:1 merger in the same time frame. The subset of analogs that have had a 4:1 merger within the last 4 Gyr are also similar to AD measurements of stars in the disk of M31, providing evidence that M31 may in fact have recently merged with a galaxy nearly one fourth of its mass. Further work using high resolution zoom in simulations is required to explore the contribution of internal heating to AD.
