论文标题
矮星系对银河球状簇轨道演化的影响
The Effects of Dwarf Galaxies on the Orbital Evolution of Galactic Globular Clusters
论文作者
论文摘要
我们研究了矮星系对银河系的轨道，潮汐历史和假定的形成环境的影响。我们确定银河系150个球状簇的轨道，具有有或没有矮星系的引力电势。我们发现，少数卫星星系的存在会影响许多球状簇的轨道。超过12 Gyr，我们发现单个簇的半轴轴和轨道偏心率分别以$ \ sim 10 \％$和$ \ sim 4 \％$ $的分散体波动。与内群相比，外部簇比内簇更强烈，其半高轴和轨道偏心率的波动分别超过$ \ sim 15 \％\％$和$ \ sim 5 \％$。使用详细的$ n $体体模拟精选簇的模拟，我们发现改变其轨道历史可以导致不同的质量损失率和结构演变。此外，我们警告不要单独使用运动学来确定在过去的合并事件中是在原位形成还是被积聚的银河簇，因为这些值不再保守。矮星系的存在导致单个簇的轨道能量和动作随着时间的流逝而发展，范围比来自群集的适当运动和径向速度的随机不确定性更大的范围。
We investigate the effect that dwarf galaxies have on the orbits, tidal histories, and assumed formation environment of Milky Way globular clusters. We determine the orbits of the Milky Way's 150 globular clusters in a gravitational potential both with and without dwarf galaxies. We find that the presence of a small number of satellite galaxies can affect the orbits of many of the globular clusters. Over 12 Gyr, we find that the semi-major axis and orbital eccentricity of individual clusters fluctuate with dispersions on the order of $\sim 10\%$ and $\sim 4\%$, respectively. Outer clusters are more strongly affected by dwarf galaxies than inner clusters, with their semi-major axis and orbital eccentricities fluctuating by more than $\sim 15\%$ and $\sim 5\%$, respectively. Using detailed $N$-body simulations of select clusters, we find that altering their orbital histories can lead to different mass loss rates and structural evolution. Furthermore, we caution against using kinematics alone to identify whether a Galactic cluster formed in-situ or was accreted during a past merger event as these values are no longer conserved. The presence of dwarf galaxies causes the orbital energies and actions of individual clusters to evolve over time, spanning a wider range than that coming from random uncertainties in a cluster's proper motions and radial velocity.
