AI 中文总结
本研究用Schwarzschild轨道叠加方法对PGC 35706和LEDA 2220522两个运动学解耦星系建模，识别出三类结构组分，验证了反转盘的形成机制，证明了Schwarzschild方法的有效性。
AI 中文摘要
我们利用MaNGA积分场光谱巡天的数据以及DESI Legacy成像巡天的深场测光数据，对两个运动学不一致的星系——PGC 35706和LEDA 2220522开展了动力学建模研究并给出结果。我们采用轴对称近似下的Schwarzschild轨道叠加方法，基于轨道圆度参数λ_z识别星系的结构组分，在这两个星系中一共识别出三类组分：椭球状（核球/暗晕）组分、共转恒星盘以及反转恒星盘。椭球状组分在两个星系的质量占比中均占主导：PGC 35706中约占60%，LEDA 2220522中约占51%；共转盘和反转盘的质量占比在PGC 35706中分别为29%和9%，在LEDA 2220522中分别为30%和18%。两个星系的电离气体运动学与反转盘的旋转特征一致，表明该反转盘由携带相反角动量的外部吸积气体形成。研究结果支持反转盘通过星系际介质气体吸积或与富气卫星发生并合形成的假说，同时也证明了Schwarzschild方法在研究星系复杂运动学结构及其形成历史方面的有效性。
英文摘要
We present the results of dynamical modeling of two galaxies with inconsistent kinematics -- PGC 35706 and LEDA 2220522 -- using data from the MaNGA integral-field spectroscopic survey and deep photometry from the DESI Legacy Imaging Surveys. The Schwarzschild orbit-superposition method in the axisymmetric approximation was employed to identify structural components based on the orbital circularity parameter $λ_z$. Three components have been identified in the galaxies: a spheroidal (bulge/halo) component and co-rotating and counter-rotating stellar disks. The spheroidal component dominates by mass in both galaxies: about 60\% in PGC 35706 and 51\% in LEDA 2220522; the contributions of the co-rotating and counter-rotating disks are 29\% and 9\% in PGC 35706 and 30\% and 18\% in LEDA 2220522, respectively. The kinematics of the ionized gas in both galaxies is consistent with the rotation of the counter-rotating disk, indicating that it formed from externally accreted gas with opposite angular momentum. The results support a scenario in which counter-rotating disks form through gas accretion from the intergalactic medium or through minor mergers with gas-rich satellites. This work demonstrates the effectiveness of the Schwarzschild method for studying the complex kinematic structure of galaxies and their formation history.
Comments16 pages, 9 figures, 1 table; published in Astrophysical Bulletin
Journal refAstrophysical Bulletin, Vol. 81, No. 3, pp. 407-423 (2026)
