Using kinematic data from the Gaia Data Release 3 catalog, along with metallicity estimates robustly derived from Gaia BP/RP spectra, we have explored the Galactic stellar halo in search of both known and potentially new substructures. By applying the Hierarchical Density-Based Spatial Clustering of Applications with Noise clustering algorithm in integrals-of-motion space (i.e., E, Lz, and L⊥ ), we identified five previously known substructures: Gaia-Sausage-Enceladus (GSE), Helmi streams, I'itoi and Sequoia, and the hot thick disk. We additionally found NGC 3201 and NGC 5139 in this work, and NGC 3201 shares similar distributions in phase space and metallicities to Arjuna, which possibly implies that they have the same origin. Three newly discovered substructures are Prograde Substructure 1 (PG1), Prograde Substructure 2 (PG2), and the Low Energy Group. PG1, with a higher Vϕ than typical GSE member stars, is considered as either a low-eccentricity and metal-rich part of GSE or part of the metal-poor disk. PG2, sharing kinematic similarities with Aleph, is thought to be its relatively highly eccentric component or the mixture of Aleph and the disk. The Low Energy Group, whose metal-poor component of metallicity distribution function has a mean value [M/H] ∼ −1.29 (compared to that of Heracles [M/H] ∼ −1.26), may have associations with Heracles.

中文翻译：

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使用 Gaia 数据版本 3 探索运动积分空间中的 Halo 子结构


使用来自 Gaia Data Release 3 目录的运动学数据，以及从 Gaia BP/RP 光谱中可靠得出的金属丰度估计，我们探索了银河系恒星晕，以寻找已知和潜在的新子结构。通过在运动积分空间（即 E、Lz 和 L）中应用基于噪声聚类算法的基于层次密度的应用程序空间聚类算法⊥我们确定了五个以前已知的子结构：Gaia-Sausage-Enceladus （GSE）、Helmi 流、I'itoi 和 Sequoia 以及热厚盘。我们还在这项工作中发现了 NGC 3201 和 NGC 5139，NGC 3201 在相空间和金属丰度上与阿朱那相似，这可能意味着它们具有相同的起源。三个新发现的子结构是顺行子结构 1 （PG1）、顺行子结构 2 （PG2） 和低能量组。PG1 的 Vφ 高于典型的 GSE 成员星，被认为是 GSE 中低偏心率和富含金属的部分，或者是贫金属盘的一部分。PG2 与 Aleph 在运动学上具有相似性，被认为是其相对高度偏心的成分或 Aleph 和圆盘的混合物。低能量组，其金属丰度分布函数的贫金属成分具有平均值 [M/H] ∼ -1.29（与赫拉克勒斯 [M/H] ∼ -1.26 相比），可能与赫拉克勒斯有关。