论文标题
年轻大型簇II的空间演变II。在NGC 2264中寻找与Gaia DR2的恒星形成的烙印
The Spatial Evolution of Young Massive Clusters II. Looking for Imprints of Star Formation in NGC 2264 with Gaia DR2
论文作者
论文摘要
目标。为了证明“指示”是一种强大的空间分析工具，当与Gaia的运动数据结合使用时，可以使用DR2的运动数据来稳健地探测星形形成历史记录。 方法。我们使用GAIA DR2适当的运动数据比较了NGC 2264的各个进化阶段的年轻恒星对象（YSO）的动态和空间分布。 结果。 YSO在不同进化阶段的动态和空间行为是不同的。从动态上讲，II类YSO主要具有与已知子结构一致的非随机轨迹，而III类YSO具有随机轨迹，没有明确的膨胀或收缩模式。在空间上，进化阶段和源浓度之间存在相关性：占0/I类的69.4％，II类的27.9％，发现III类物体的7.7％被聚集。与同一类的对象聚集的YSO的比例也遵循了这一趋势。与IIS和III类的一般人口/对象相比，类别为0/I对象的群体与同一类的一般人口/对象分别为1.2/4.1和1.9/6.6。这些发现的一个例外是在s mon的0.05吉姆内，其中III类对象模仿了整个较宽的群集区域的II类源的行为。我们的结果表明（i）当前的YSOS分布是动态演化的结果，（ii）延长的恒星形成已经依次发生，（iii）（iii）来自s mon的恒星反馈使ysoS导致ysos显示为更多进化的来源。 结论。旨在提供集群行为的定量度量，表明是执行严格空间分析的强大工具。我们的发现与关于NGC 2264的已知结果一致，有效地表明，与Gaia Dr2的运动学数据结合在一起，表明可以使用群集的恒星形成历史来牢固地研究。
Aims. To demonstrate that `INDICATE' is a powerful spatial analysis tool which when combined with kinematic data from Gaia DR2 can be used to robustly probe star formation history. Methods. We compared the dynamic & spatial distributions of young stellar objects (YSOs) at various evolutionary stages in NGC 2264 using Gaia DR2 proper motion data and INDICATE. Results. The dynamic & spatial behaviours of YSOs at different evolutionary stages are distinct. Dynamically, Class II YSOs predominately have non-random trajectories that are consistent with known substructures, whereas Class III YSOs have random trajectories with no clear expansion or contraction patterns. Spatially, there is a correlation between the evolutionary stage and source concentration: 69.4% of Class 0/I, 27.9% of Class II, and 7.7% of Class III objects are found to be clustered. The proportion of YSOs clustered with objects of the same class also follows this trend. Class 0/I objects are both found to be more tightly clustered with the general populous/objects of the same class than Class IIs and IIIs by a factor of 1.2/4.1 and 1.9/6.6, respectively. An exception to these findings is within 0.05deg of S Mon where Class III objects mimic the behaviours of Class II sources across the wider cluster region. Our results suggest (i) current YSOs distributions are a result of dynamical evolution, (ii) prolonged star formation has been occurring sequentially, and (iii) stellar feedback from S Mon is causing YSOs to appear as more evolved sources. Conclusions. Designed to provide a quantitative measure of clustering behaviours, INDICATE is a powerful tool with which to perform rigorous spatial analyses. Our findings are consistent with what is known about NGC 2264, effectively demonstrating that when combined with kinematic data from Gaia DR2 INDICATE can be used to robustly study the star formation history of a cluster.
