Resolving local and global kinematic signatures of satellite mergers with billion particle simulations
Resolving local and global kinematic signatures of satellite mergers with billion particle simulations
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DOI：
10.1093/mnras/stab2580
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发表时间：
2021-07
影响因子：
4.8
通讯作者：
Jason A. S. Hunt;I. Stelea;K. Johnston;Suroor S. Gandhi;C. Laporte;J. Bédorf
中科院分区：
文献类型：
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作者：
Jason A. S. Hunt;I. Stelea;K. Johnston;Suroor S. Gandhi;C. Laporte;J. Bédorf
在这项工作中，我们提出了两个新的109粒子的自洽模拟合并的人马座矮星系与银河系（MW）的盘状星系。一种模型是剧烈的合并产生了一个厚厚的圆盘，和一个盖亚-土卫二/香肠状的残余物。另一个是一个高度稳定的圆盘，我们用它来说明改进的相空间分辨率如何使我们能够更好地研究在MW中小的局部体积中观察到的结构的形成和演变，例如z-vz相螺旋和vR-v平面中的聚类。局部z-vz相位螺旋显然与整个圆盘的全局不对称性有关：我们发现了双臂和单臂相位螺旋，它们分别与呼吸和弯曲行为有关。像大力神一样的移动群体很常见，在模拟中的本地数据样本中聚集在vR-v中。这些群体从星系内部向外迁移，即使在没有星系棒的情况下也与观测到的金属丰度趋势相匹配。我们目前发布了最合适的“当今”合并快照沿着与未扰动星系进行比较。
In this work, we present two new ∼109 particle self-consistent simulations of the merger of a Sagittarius-like dwarf galaxy with a Milky Way (MW)-like disc galaxy. One model is a violent merger creating a thick disc, and a Gaia–Enceladus/Sausage-like remnant. The other is a highly stable disc which we use to illustrate how the improved phase space resolution allows us to better examine the formation and evolution of structures that have been observed in small, local volumes in the MW, such as the z−vz phase spiral and clustering in the vR−vϕ plane when compared to previous works. The local z−vz phase spirals are clearly linked to the global asymmetry across the disc: we find both 2-armed and 1-armed phase spirals, which are related to breathing and bending behaviours, respectively. Hercules-like moving groups are common, clustered in vR−vϕ in local data samples in the simulation. These groups migrate outwards from the inner galaxy, matching observed metallicity trends even in the absence of a galactic bar. We currently release the best-fitting ‘present-day’ merger snapshots along with the unperturbed galaxies for comparison.