论文标题

在\ textit {gaia} dr2中寻找开放群集

Hunting for open clusters in \textit{Gaia} DR2: $582$ new OCs in the Galactic disc

论文作者

Castro-Ginard, A., Jordi, C., Luri, X., Cid-Fuentes, J. Álvarez, Casamiquela, L., Anders, F., Cantat-Gaudin, T., Monguió, M., Balaguer-Núñez, L., Solà, S., Badia, R. M.

论文摘要

开放簇是星系结构和进化和恒星物理研究的关键目标。由于\ textit {gaia} dr2出版物,因此未检测到的簇的发现证明了我们的样品未完成。我们的目的是利用机器学习的大数据功能,以检测\ textit {gaia} dr2中的新开放群集,并完成开放群集样品,以实现对银河盘的进一步研究。我们使用基于机器学习的方法在银河盘中系统地搜索,寻找天体空间中的过度,并使用光度信息将其识别为开放群集。首先,我们使用一种无​​监督的聚类算法DBSCAN,盲目地搜索这些过度,以\ textit {gaia} dr2 $(l,b,b,\ varpi,μ__{α^*},μ_Δ)$。之后,我们使用经过颜色魔术图训练的深度学习人工神经网络来识别这些过度繁殖中的等线性模式,并确认它们为开放簇。我们发现$ 582 $ $ | b |在该地区的银河盘上分发的新开放式群集<20 $。我们可以在复杂区域检测子结构,并确定破坏群集UBC的潮汐尾巴〜$ 274 $ \ sim 3 $ gyr位于$ \ sim 2 $ kpc。将方法调整为大数据环境,使我们能够针对由开放群集的物理属性驱动的搜索,而不是由其计算要求驱动。在银河光盘中,对开放式簇的盲目搜索增加了$ 45 \%$已知的开放式群集的数量。

Open clusters are key targets for both Galaxy structure and evolution and stellar physics studies. Since \textit{Gaia} DR2 publication, the discovery of undetected clusters has proven that our samples were not complete. Our aim is to exploit the Big Data capabilities of machine learning to detect new open clusters in \textit{Gaia} DR2, and to complete the open cluster sample to enable further studies on the Galactic disc. We use a machine learning based methodology to systematically search in the Galactic disc, looking for overdensities in the astrometric space and identifying them as open clusters using photometric information. First, we use an unsupervised clustering algorithm, DBSCAN, to blindly search for these overdensities in \textit{Gaia} DR2 $(l,b,\varpi,μ_{α^*},μ_δ)$. After that, we use a deep learning artificial neural network trained on colour-magnitude diagrams to identify isochrone patterns in these overdensities, and to confirm them as open clusters. We find $582$ new open clusters distributed along the Galactic disc, in the region $|b| < 20$. We can detect substructure in complex regions, and identify the tidal tails of a disrupting cluster UBC~$274$ of $\sim 3$ Gyr located at $\sim 2$ kpc. Adapting the methodology into a Big Data environment allows us to target the search driven by physical properties of the open clusters, instead of being driven by its computational requirements. This blind search for open clusters in the Galactic disc increases in a $45\%$ the number of known open clusters.

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