ABSTRACT

Galaxy interactions distort the distribution of baryonic matter and can affect star formation. The nearby Magellanic Clouds are a prime example of an ongoing galaxy interaction process. Here, we use the intermediate-age (∼1–10 Gyr) red clump (RC) stars to map the 3D structure of the Small Magellanic Cloud (SMC) and interpret it within the context of its history of interaction with the Large Magellanic Cloud (LMC) and the Milky Way. RC stars are selected from near-infrared colour–magnitude diagrams based on data from the Visible and Infrared Survey Telescope for Astronomy survey of the Magellanic Clouds. Interstellar reddening is measured and removed, and the corrected brightness is converted to a distance, on a star-by-star basis. A flat plane fitted to the spatial distribution of RC stars has an inclination i = 35°–48° and position angle, PA=170°–186°. However, significant deviations from this plane are seen, especially in the periphery and on the eastern side of the SMC. In the latter part, two distinct populations are present, separated in distance by as much as 10 kpc. Distant RC stars are seen in the north of the SMC, and possibly also in the far west; these might be associated with the predicted ‘Counter-Bridge’. We also present a dust reddening map, which shows that dust generally traces stellar mass. The structure of the intermediate-age stellar component of the SMC bears the imprints of strong interaction with the LMC a few Gyr ago, which cannot be purely tidal but must have involved ram pressure stripping.

中文翻译：

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VMC调查– XL。由红色团块星衍生的小麦哲伦星云的三维结构

摘要

星系的相互作用扭曲了重子物质的分布，并可能影响恒星的形成。附近的麦哲伦星云是正在进行的星系相互作用过程的主要示例。在这里，我们使用中等年龄（约1–10 Gyr）的红色团块（RC）来绘制小麦哲伦星云（SMC）的3D结构，并在其与大麦哲伦星云相互作用的历史背景下对其进行解释（LMC）和银河系。RC恒星是根据来自麦哲伦星云的天文观测用可见光和红外测量望远镜的数据从近红外色度图中选择的。测量并消除星际变红，并将校正后的亮度逐颗转换为距离。装配到RC分的空间分布的平面具有倾斜我= 35°–48°和位置角，PA = 170°–186°。但是，可以看到与该平面的明显偏差，特别是在SMC的外围和东侧。在后一部分中，存在两个不同的种群，它们之间的距离相距多达10 kpc。在SMC的北部，甚至在遥远的西部，都可以看到遥远的RC恒星。这些可能与预测的“ Counter-Bridge”相关联。我们还显示了粉尘变红图，该图显示粉尘通常跟踪恒星质量。SMC的中年恒星组件的结构具有与吉尔（Gyr）之前的LMC强烈相互作用的印记，这不能纯粹是潮汐，但必须涉及冲压压力剥离。