Searching for the extra-tidal stars of globular clusters using high-dimensional analysis and a core particle spray code
Searching for the extra-tidal stars of globular clusters using high-dimensional analysis and a core particle spray code
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使用高维分析和核心粒子喷射代码搜索球状星团的潮外恒星
DOI：
10.1093/mnras/stac3367
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发表时间：
2022
影响因子：
4.8
通讯作者：
Reem J. Khalifeh
中科院分区：
文献类型：
--
作者：
S. Grondin;J. Webb;N. Leigh;J. Speagle;Reem J. Khalifeh
三体相互作用可以将恒星从球状星团的核心弹射出来，使它们作为潮外星进入银河系晕。虽然寻找潮外恒星对于理解星团演化至关重要，但将孤立的潮外恒星与它们的诞生星团联系起来是非常困难的。在这项工作中，我们提出了一种新的方法，包括高维数据分析和粒子喷雾代码，以确定任何银河系球状星团的潮外星M3作为一个案例研究。使用t-随机邻域嵌入（t-SNE）和均匀流形近似和投影（UMAP）机器学习降维算法，我们首先在APOGEE DR 17数据目录中识别出一组103个潮汐外候选者，其化学丰度类似于M3恒星。为了确认每个候选者的潮汐外性质，我们介绍了corespray -一个新的基于Python的三体粒子喷雾代码，模拟任何银河系球状星团的潮汐外恒星。使用盖亚EDR 3自行和APOGEE DR 17径向速度，我们采用多元高斯建模和极端反卷积，以确定更有可能与corespray模拟的M3潮汐外恒星的分布相关联的潮汐外候选者。通过这些方法，我们确定了10个新的高概率通过三体相互作用在M3产生的潮外星。我们还探讨了是否有任何我们的潮汐外候选人是一致的，通过不同的动力学过程从M3弹射。corespray的未来应用将产生更好的理解核心动力学，星星的形成历史和球状星团中的双星分数。
Three-body interactions can eject stars from the core of a globular cluster, causing them to enter the Galactic halo as extra-tidal stars. While finding extra-tidal stars is imperative for understanding cluster evolution, connecting isolated extra-tidal field stars back to their birth cluster is extremely difficult. In this work, we present a new methodology consisting of high-dimensional data analysis and a particle spray code to identify extra-tidal stars of any Galactic globular cluster using M3 as a case study. Using the t-Stochastic Neighbour Embedding (t-SNE) and Uniform Manifold Approximation and Projection (UMAP) machine learning dimensionality reduction algorithms, we first identify a set of 103 extra-tidal candidates in the APOGEE DR17 data catalogue with chemical abundances similar to M3 stars. To confirm each candidate’s extra-tidal nature, we introduce corespray - a new Python-based three-body particle spray code that simulates extra-tidal stars for any Galactic globular cluster. Using Gaia EDR3 proper motions and APOGEE DR17 radial velocities, we apply multivariate Gaussian modelling and an extreme deconvolution to identify the extra-tidal candidates that are more likely to be associated with a distribution of corespray-simulated M3 extra-tidal stars than the field. Through these methods, we identify 10 new high-probability extra-tidal stars produced via three-body interactions in M3. We also explore whether any of our extra-tidal candidates are consistent with being ejected from M3 through different dynamical processes. Future applications of corespray will yield better understandings of core dynamics, star formation histories and binary fractions in globular clusters.