论文标题

VMC调查-XLV。外LMC的正确运动和SMC的影响

The VMC survey -- XLV. Proper motion of the outer LMC and the impact of the SMC

论文作者

Schmidt, Thomas, Cioni, Maria-Rosa L., Niederhofer, Florian, Bekki, Kenji, Bell, Cameron P. M., de Grijs, Richard, Youssoufi, Dalal El, Ivanov, Valentin D., Oliveira, Joana M., Ripepi, Vincenzo, van Loon, Jacco Th.

论文摘要

大型麦哲伦云(LMC)是银河系中最具发光的卫星星系,并且由于其伴侣小麦哲伦云(SMC)是研究矮星系相互作用的出色实验室。这项研究的目的是通过使用恒星适当的运动来了解相互作用的影响,例如与SMC大约250 Myr之前。 {我们使用Multi-Epoch $ K_ \ Mathrm {s} $计算适当的运动 - 来自Magellanic Clouds System(VMC)Vista调查的频段图像。观测值跨度为2 $ - $ 5年的时间基线。我们将VMC数据与Gaia早期数据版本3的数据结合在一起,并引入了一种新方法,以根据机器学习算法来区分麦哲伦和银河系星星。这项新技术可以在LMC的红色团块以下,可以选择更大,更清洁的淡淡来源。我们研究了SMC对LMC旋转场的影响,并找到了剥离的SMC碎片的提示。与整体旋转相比,LMC的东南区域显示出缓慢的旋转速度。 $ n $ - 体仿真表明,这可能是由于位于该特定区域的一小部分SMC恒星与预期旋转相反。

The Large Magellanic Cloud (LMC) is the most luminous satellite galaxy of the Milky Way and owing to its companion, the Small Magellanic Cloud (SMC), represents an excellent laboratory to study the interaction of dwarf galaxies. The aim of this study is to investigate the kinematics of the outer regions of the LMC by using stellar proper motions to understand the impact of interactions, e.g. with the SMC about 250 Myr ago. {We calculate proper motions using multi-epoch $K_\mathrm{s}$-band images from the VISTA survey of the Magellanic Clouds system (VMC). Observations span a time baseline of 2$-$5 yr. We combine the VMC data with data from the Gaia early Data Release 3 and introduce a new method to distinguish between Magellanic and Milky Way stars based on a machine learning algorithm. This new technique enables a larger and cleaner sample selection of fainter sources as it reaches below the red clump of the LMC. We investigate the impact of the SMC on the rotational field of the LMC and find hints of stripped SMC debris. The south east region of the LMC shows a slow rotational speed compared to the overall rotation. $N$-body simulations suggest that this could be caused by a fraction of stripped SMC stars, located in that particular region, that move opposite to the expected rotation.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源