标题： S2D2：小规模显著子结构DBSCAN检测 I. 二维恒星形成区域中的NESTs检测 显示英文标题

标题： S2D2: Small-scale Significant substructure DBSCAN Detection I. NESTs detection in 2D star-forming regions

摘要： 恒星形成区域的空间和动力结构有助于提供关于恒星形成模式的见解。 当前和即将进行的调查所产生的数据量要求采用稳健且客观的程序来检测结构，以便结果可以进行统计分析并比较不同的区域。 我们为社区提供了一个工具，能够在恒星形成区域中检测出超出随机预期的小尺度显著结构，这可能是恒星形成过程的痕迹。 该工具利用一点关联函数和最近邻统计量来确定DBSCAN算法的参数。 该程序成功地检测了异质区域中的显著小尺度子结构，实现了其设计目标，并提供了非常可靠的结果。 对接近完全空间随机性（$Q \in [0.7,0.87]$）的区域进行分析表明，即使某些结构存在并被恢复，在均质区域中由于投影效应，这些结构很难与虚假检测区分开来。 因此，解释应谨慎进行。 对于集中区域，我们检测到一个主要结构，周围有较小的结构，对应于核心以及其周围的某些泊松波动。 我们认为这些结构并不对应于我们寻找的小而紧凑的区域。 在一些现实情况下，需要更完整的分层、多尺度分析来捕捉区域的复杂性。 我们已经开发了该程序的实现，并创建了一个目录，记录了它在四个恒星形成区域（Taurus、IC 348、Upper Scorpius 和 Carina）中检测到的NESTs（嵌套的基本结构），这些数据对社区公开可用。 该程序的3D版本以及最多6D版本（包括自行运动）的实现正在进行中，将在未来工作中提供。 显示英文摘要

摘要： The spatial and dynamical structure of star-forming regions can help provide insights on stellar formation patterns. The amount of data from current and upcoming surveys calls for robust and objective procedures to detect structure, so the results can be statistically analysed and different regions compared. We provide the community with a tool able to detect the small scale significant structure, above random expectation, in star-forming regions, which could be the imprint of the stellar formation process. The tool makes use of the one point correlation function and of nearest neighbour statistics to determine the parameters for the DBSCAN algorithm. The procedure successfully detects significant small scale substructures in heterogeneous regions, fulfilling the goals it was designed for, and providing very reliable structures. The analysis of regions close to complete spatial randomness ($Q \in [0.7,0.87]$) shows that, even when some structure is present and recovered, it is hardly distinguishable from spurious detection in homogeneous regions due to projection effects. Interpretation should thus be done with care. For concentrated regions, we detect a main structure surrounded by smaller ones, corresponding to the core plus some Poisson fluctuations around it. We argue that these structures do not correspond to the small compact regions we are looking for. In some realistic cases, a more complete hierarchical, multi-scale analysis would be needed to capture the complexity of the region. We have developed implementations of our procedure, and a catalogue of the NESTs (Nested Elementary STructures) detected by it in four star-forming regions (Taurus, IC 348, Upper Scorpius, and Carina), which are publicly available to the community. Implementations of the 3D, and up to 6D versions of the procedure including proper movements are in progress, and will be provided as future work.