论文标题
哈勃太空望远镜调查麦哲伦云星簇。 113个簇和早期结果的光度法和天文学
Hubble Space Telescope survey of Magellanic Cloud star clusters. Photometry and astrometry of 113 clusters and early results
论文作者
论文摘要
在过去的几年中,我们根据HST数据对LMC和SMC星团进行了广泛的研究。我们提出了使用WFC/ACS,UVIS/WFC3和NIR/WFC3摄像机观察到的101个磁场中恒星的光度法和星形学。这些字段包括113个星团。我们提供差异的降低地图,并说明了由于对光度表目录的早期检查而产生的各种科学结果。特别是,我们提供了有关扩展的主要序列关闭(EMSTO)现象的新见解:i)我们在两个群集KMHK361和NGC265中检测到EMSTOS,该簇以前没有多个人群的证据。这一发现证实了以下结论:emsto是大于2 gyr的簇中的广泛现象。 ii)19个LMC簇的均匀颜色图表(CMDS)表明,沿EMSTO的恒星的分布取决于聚类的年龄。 iii)我们在NGC1783的EMSTO上发现了一个新功能,该功能由由CMDS组成的一组恒星组成,该恒星由紫外线过滤器组成。此外,我们在具有多个上方图像的群集视野中得出了恒星的适当运动。适当的运动使我们能够将大部分明亮田间星星与群集成员分开,并研究各种LMC和SMC场中恒星种群的内部运动学。例如,我们分析了NGC346周围的田地,以消除其恒星种群的动作,包括NGC364和BS90,与NGC346相关的星形形成区域的年轻和前MS星,以及SMC的年轻人和老田间恒星种群。基于这些结果和五个额外的群集的田地,我们发现年轻的SMC星表现出伸长的运动分布,这些分布指向LMC,从而为LMC和SMC之间的运动学连接带来了新的证据。
In the past years, we have undertaken an extensive investigation of LMC and SMC star clusters based on HST data. We present photometry and astrometry of stars in 101 fields observed with the WFC/ACS, UVIS/WFC3 and NIR/WFC3 cameras. These fields comprise 113 star clusters. We provide differential-reddening maps and illustrate various scientific outcomes that arise from the early inspection of the photometric catalogs. In particular, we provide new insights on the extended main-sequence turn-off (eMSTO) phenomenon: i) We detected eMSTOs in two clusters, KMHK361 and NGC265, which had no previous evidence of multiple populations. This finding corroborates the conclusion that the eMSTO is a widespread phenomenon among clusters younger than ~2 Gyr. ii) The homogeneous color-magnitude diagrams (CMDs) of 19 LMC clusters reveal that the distribution of stars along the eMSTO depends on cluster age. iii) We discovered a new feature along the eMSTO of NGC1783, which consists of a distinct group of stars going on the red side of the eMSTO in CMDs composed of ultraviolet filters. Furthermore, we derived the proper motions of stars in the fields of view of clusters with multi-epoch images. Proper motions allowed us to separate the bulk of bright field stars from cluster members and investigate the internal kinematics of stellar populations in various LMC and SMC fields. As an example, we analyze the field around NGC346 to disentangle the motions of its stellar populations, including NGC364 and BS90, young and pre-MS stars in the star-forming region associated with NGC346, and young and old field stellar populations of the SMC. Based on these results and the fields around five additional clusters, we find that young SMC stars exhibit elongated proper-motion distributions that point toward the LMC, thus bringing new evidence for a kinematic connection between the LMC and SMC.