具有运动学错位成分的星系的恒星族群与动力学建模：结构成分的年龄和金属丰度
Stellar Population and Dynamical Modeling of Galaxies with Kinematically Misaligned Components: Age and Metallicity of Structural Components
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- Sternberg Astronomical Institute（斯登伯格天文研究所）
- M. V. Lomonosov Moscow State University（莫斯科罗蒙诺索夫国立大学）
- Astrospace Center of the P. N. Lebedev Physical Institute, Russian Academy of Sciences（俄罗斯科学院列别捷夫物理研究所太空中心）
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中文总结 AI 辅助
本文对两个具有运动学错位成分的星系PGC 35706和LEDA 2220522开展恒星族群与轨道建模，扩展Schwarzschild动力学模型，揭示其结构成分的年龄与金属丰度特征，明确该方法适用于MaNGA数据的条件。
中文摘要 AI 辅助
我们对两个具有运动学错位成分的星系PGC 35706和LEDA 2220522开展恒星族群与轨道建模，扩展了此前的Schwarzschild动力学模型。利用NBursts对MaNGA数据结合E-MILES网格进行全谱拟合得到的空间分辨年龄和金属丰度图，我们求解一个正则化有界线性逆问题，该问题将光加权的简单星族（SSP）等效年龄、金属丰度以及质量-光比分配给(R,λ_z)平面内的轨道单元。成分均值与径向轮廓采用MaNGA实际视场内的投影质量；局部成分占比低于1%的轮廓段被视为弱约束。在LEDA 2220522中，反向旋转盘比同向旋转盘更年轻，分别为1.32±0.04 Gyr和1.61±0.06 Gyr，且金属丰度更高，[M/H]分别为-0.450±0.043和-0.613±0.024。其旋转与Hα电离气体的旋转一致，支持晚期供给化学增丰的逆行气体，而无需具有交替角动量的多次吸积事件。在PGC 35706中，反向旋转盘在观测视场内占8.8%的质量，形式上比同向旋转盘老1.36±0.51 Gyr，金属丰度低0.130±0.046 dex。由于投影数据的约束有限，这些差异是初步的。50次蒙特卡洛实现证实投影图对统计噪声具有稳定性，但无法保证单个相空间单元的唯一性。因此，当明确考虑局部投影成分占比以及正则化和动力学模型带来的系统误差时，该恒星族群与轨道方法适用于MaNGA数据。
英文摘要
We present stellar population and orbit modeling of two galaxies with kinematically misaligned components, PGC 35706 and LEDA 2220522, extending previous Schwarzschild dynamical models. Using spatially resolved age and metallicity maps from NBursts full spectral fitting of MaNGA data with the E-MILES grid, we solve a regularized bounded linear inverse problem that assigns light-weighted SSP-equivalent age, metallicity, and mass-to-light ratio to orbital cells in the $(R,λ_z)$ plane. Component means and radial profiles use projected mass within the actual MaNGA field of view; profile segments with local component fractions below $1\%$ are treated as weakly constrained. In LEDA 2220522, the counter-rotating disk is younger than the co-rotating disk, $1.32\pm0.04$ versus $1.61\pm0.06$ Gyr, and more metal-rich, $[\mathrm{M/H}]=-0.450\pm0.043$ versus $-0.613\pm0.024$. Its rotation agrees with that of the H$α$ ionized gas, supporting late supply of chemically enriched retrograde gas without requiring multiple accretion episodes with alternating angular momentum. In PGC 35706, the counter-rotating disk contains $8.8\%$ of the mass in the observed field and is formally older than the co-rotating disk by $1.36\pm0.51$ Gyr and more metal-poor by $0.130\pm0.046$ dex. These differences are preliminary because the projected data provide limited support. Fifty Monte Carlo realizations confirm stability of the projected maps against statistical noise, but not uniqueness in individual phase-space cells. The stellar population and orbit approach is therefore applicable to MaNGA data when local projected component fractions and systematics from regularization and the dynamical model are explicitly considered.
