论文标题
径向作用在银河盘中的扩散
Diffusion of radial action in a galactic disc
论文作者
论文摘要
语境。援引银河圆盘恒星的恒星迁移已被援引，以解释在太阳能街区观察到的恒星金属性的分散。目标。我们试图确定在棒的影响下，在孤立的星系盘中恒星迁移的动力学机制。我们的方法是分析动力学数量的扩散。方法。我们通过在理想化的n $ - $身体模拟中探索径向动作$ j_ \ mathrm {r} $的Chirikov的扩散率（和派生时间尺度）来扩展我们以前的工作。我们将研究限制为在绝热进化方面形成棒后圆盘区域的演变。结果。 $ J_ \ MATHRM {R} $ diffusion timescales $ t_ \ mathrm {d}（j_ \ mathrm {r}）$对于大约一半的星系质量而言小于3 gyr。它总是比角动量扩散时间尺度$ t_ \ mathrm {d}（l_ \ mathrm {z}）$短得多。在光盘中，$ \ langle t_ \ mathrm {d}（j_ \ mathrm {r}）\ rangle \ sim 1 $ gyr。圆盘中共振和波的所有非轴对称形态结构的特征与$ t_ \ mathrm {d}（j_ \ mathrm {r}）<3 $ gyr和$ t_ \ t_ \ mathrm {d}（l_ \ mathrm {z mathrm {z}}）> 10 $ gyr。简短的$ t_ \ mathrm {d}（j_ \ mathrm {r}）$可以通过最初的圆形轨道（$ j_ \ mathrm {r} = 0 $）的逐渐变圆形化来解释，这是在间歇性的ILR散射的影响下通过在圆盘中传播的ILR散射的效果，超越了Bar Olr。这会导致圆盘的中等世俗加热，超出杆OLR，进行7 Gyr，与太阳邻居观测相当。复杂的多波结构，将永久性和间歇模式混合，允许多个共振重叠。
Context. Stellar migration of the galactic disc stars has been invoked to explain the dispersion of stellar metallicity observed in the solar neighborhood. Aims. We seek to identify the dynamical mechanisms underlying stellar migration in an isolated galaxy disc under the influence of a bar. Our approach is to analyze the diffusion of dynamical quantities. Methods. We extend our previous work by exploring Chirikov's diffusion rate (and derived timescale) of the radial action $J_\mathrm{R}$ in an idealised N$-$body simulation of an isolated disc galaxy. We limit our study to the evolution of the disc region well after the formation of the bar, in a regime of adiabatic evolution. Results. The $J_\mathrm{R}$ diffusion timescales $T_\mathrm{D}(J_\mathrm{R})$ is less than 3 Gyr for roughly half the galaxy mass. It is always much shorter than the angular momentum diffusion timescale $T_\mathrm{D}(L_\mathrm{z})$ outside the stellar bar. In the disc, $\langle T_\mathrm{D}(J_\mathrm{R}) \rangle \sim 1$ Gyr. All non-axisymmetric morphological structures characteristic of resonances and waves in the disc are associated to particles with $T_\mathrm{D}(J_\mathrm{R}) < 3$ Gyr and $T_\mathrm{D}(L_\mathrm{z}) > 10$ Gyr. Short $T_\mathrm{D}(J_\mathrm{R})$ can be explained by the gradual decircularisation of initially circular orbits ($J_\mathrm{R}=0$) under the effect of intermittent ILR scattering by wave trains propagating in the disc, well beyond the bar OLR. This leads to a moderate secular heating of the disc beyond the bar OLR for 7 Gyr, comparable to solar neighbourhood observations. The complex multi-wave structure, mixing permanent and intermittent modes, allows for multiple resonance overlaps.
