恒星形成率与分子云不同性质的关系

IF 1.9 4区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS
Ashok Mondal , Tanuka Chattopadhyay
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引用次数: 0

摘要

利用多变量无监督机器学习技术研究了银河系中分子云(MCs)的性质及其恒星形成情况,涉及多个可观测参数。首先,利用标准的 K-means 聚类方法将 MCs 分成四个一致的组。随后,通过应用 Elbow 方法估算出最佳的组数,并计算剪影宽度以进行稳健性检查。随后,通过上述几个可观测参数和计算参数(如恒星形成率(SFRs)、新星质量、质量谱、动力学时间尺度(Td)等)对星团的性质进行了研究,以深入了解这些云的恒星形成过程和动力学演化过程。研究发现,星团1适合形成场恒星、双星对或恒星联合体,而星团2和星团3的云则有利于形成中等质量的银河系星团,星团4则可能产生大质量银河系星团以及少数球状星团。令人惊讶的是,在每个星团中,银河系中心半径∼8 kpc附近和近银河系平面上的云的SFR明显偏低。这些现象表明,该区域的恒星形成现象尚未开始或有可能开始。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
Dependence of star formation rate on different properties of molecular clouds

Properties of molecular clouds (MCs) lying in our Galaxy and their star formation scenarios have been investigated with the help of multivariate unsupervised machine learning techniques concerning several observable parameters. At first, the MCs have been classified into four coherent groups using the standard K-means clustering method. Subsequently, the optimum number of groups has been estimated by applying the Elbow method as well as the computation of Silhouette widths for a robustness check. Later, the properties of the groups are studied through several observable parameters as mentioned along with computed ones e.g. star formation rates (SFRs), virial masses, mass-spectra, dynamical time scales (Td), etc. to get a deeper understanding of the star formation process and dynamical evolution of these clouds. It is found that cluster 1 is suitable for the formation of field stars, binary pairs, or stellar associations, whereas the clouds in cluster 2 and cluster 3 are favorable sites for the formation of Galactic clusters of moderate masses, and cluster 4 may produce massive Galactic clusters as well as a few globular clusters. Surprisingly, for each cluster, clouds at around Galacto-centric radius 8 kpc, and on the near Galactic plane has a significantly low SFR. These occurrences indicate that the star formation phenomenon has yet not started or the proneness to start in that region.

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来源期刊
New Astronomy
New Astronomy 地学天文-天文与天体物理
CiteScore
4.00
自引率
10.00%
发文量
109
审稿时长
13.6 weeks
期刊介绍: New Astronomy publishes articles in all fields of astronomy and astrophysics, with a particular focus on computational astronomy: mathematical and astronomy techniques and methodology, simulations, modelling and numerical results and computational techniques in instrumentation. New Astronomy includes full length research articles and review articles. The journal covers solar, stellar, galactic and extragalactic astronomy and astrophysics. It reports on original research in all wavelength bands, ranging from radio to gamma-ray.
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