AI 中文总结
利用盖亚DR3和LAMOST DR7的恒星样本研究银河系盘速度子结构，发现Z - V_Z相空间中V_R条纹有双臂螺旋，后发座移动星群贡献显著，其恒星相关参数与共振相符，模拟证实特定条件可产生此类螺旋。
AI 中文摘要
我们使用盖亚DR3和LAMOST DR7的370万颗交叉匹配恒星样本，研究银河系盘中的速度子结构。作为引导中心半径R_g函数的中值径向速度V_R呈现正负交替条纹，与已知移动星群强烈相关。通过检查Z - V_Z相空间中的V_R分布，发现D1、P2、D2和P3的V_R条纹显示出清晰的双臂螺旋。在这些V_R条纹中的移动星群中，P3条纹中的后发座移动星群呈现最明显的双臂螺旋，是整体P3螺旋左臂的主要贡献者。其恒星的角动量、偏心率、轨道频率和频率比与螺旋臂的共转共振或棒的m = 4内林德布拉德共振一致。测试粒子模拟证实，具有变化模式速度的棒与静态或瞬态螺旋臂可产生此类双臂螺旋。
英文摘要
We use a cross-matched sample of 3.7 million stars from Gaia DR3 and LAMOST DR7 to investigate the velocity substructures in the Milky Way disk. The median radial velocity $V_R$ as a function of guiding-center radius $R_g$ exhibits alternating positive and negative stripes, which are strongly correlated with known moving groups. By examining the $V_R$ distribution in the $Z$--$V_Z$ phase space, we find that the D1, P2, D2, and P3 $V_R$ stripes display clear two-armed spirals. Among the moving groups embedded in these $V_R$ stripes, the Coma Berenices moving group in the P3 stripe exhibits the most pronounced two-armed spiral and serves as the primary contributor to the left arm of the overall P3 spiral. The angular momentum, eccentricities, orbital frequencies, and frequency ratios of its stars are consistent with either the corotation resonance of the spiral arms or the $m=4$ inner Lindblad resonance of the bar. Test-particle simulations confirm that a bar with a varying pattern speed, together with static or transient spiral arms, can produce such two-armed spirals.
Comments33 pages, 21 figures
Journal refYan, Xu 2026, ApJ, 1006, 143
