论文标题
麦哲伦边缘调查III。受干扰的LMC郊区的运动学
The Magellanic Edges Survey III. Kinematics of the disturbed LMC outskirts
论文作者
论文摘要
我们使用Magellanic Edges调查(MAGES)和GAIA EDR3的数据探索大麦芽云(LMC)郊区的结构和运动学特性。即使在大型的半乳半radii($ 8^\ circ <r <11^\ circ $),我们发现东北LMC磁盘相对不受干扰:它的运动学与倾斜度〜$ 36.5^\ circ $ and Circ $ and Circ $ and Line-Nonodes位置倾斜度〜$ 145^\ $ 145^\ $ East $ East $ East。相比之下,南部和西部磁盘的类似半径的田地显着从平衡中扰动,具有非零的径向和垂直速度,并且在我们的东北田地暗示的磁盘平面前面显着距离。我们将观察结果与麦哲伦/银河系系统的简单动力学模型进行了比较,该模型将LMC描述为刚性电势内的示踪剂颗粒的集合,而小麦哲伦云(SMC)则是刚性的疝气潜力。 LMC磁盘平面可能的SMC穿越〜400 Myr以前,结合LMC的内部到银河系的潜力,可以定性地解释外磁盘中的许多扰动。此外,我们发现LMC以南的爪状结构和臂状结构具有与外LMC磁盘([Fe/H]〜-1)相似的金属度,并且可能由扰动的LMC磁盘材料组成。类似爪状的子结构特别令人不安,平面速度> 60 km s $^{ - 1} $,并且相对于LMC的磁盘运动明显反旋转。更详细的N体模型对于阐明这些南部特征的起源是必要的,可能需要在〜1 Gyr之前与SMC重复相互作用。
We explore the structural and kinematic properties of the outskirts of the Large Magellanic Cloud (LMC) using data from the Magellanic Edges Survey (MagES) and Gaia EDR3. Even at large galactocentric radii ($8^\circ<R<11^\circ$), we find the north-eastern LMC disk is relatively unperturbed: its kinematics are consistent with a disk of inclination ~$36.5^\circ$ and line-of-nodes position angle ~$145^\circ$ east of north. In contrast, fields at similar radii in the southern and western disk are significantly perturbed from equilibrium, with non-zero radial and vertical velocities, and distances significantly in front of the disk plane implied by our north-eastern fields. We compare our observations to simple dynamical models of the Magellanic/Milky Way system which describe the LMC as a collection of tracer particles within a rigid potential, and the Small Magellanic Cloud (SMC) as a rigid Hernquist potential. A possible SMC crossing of the LMC disk plane ~400 Myr ago, in combination with the LMC's infall to the Milky Way potential, can qualitatively explain many of the perturbations in the outer disk. Additionally, we find the claw-like and arm-like structures south of the LMC have similar metallicities to the outer LMC disk ([Fe/H]~-1), and are likely comprised of perturbed LMC disk material. The claw-like substructure is particularly disturbed, with out-of-plane velocities >60 km s$^{-1}$ and apparent counter-rotation relative to the LMC's disk motion. More detailed N-body models are necessary to elucidate the origin of these southern features, potentially requiring repeated interactions with the SMC prior to ~1 Gyr ago.