论文标题
仙女座星系中巨大恒星流的祖细胞的金属性分布
Metallicity distribution of the progenitor of the Giant Stellar Stream in the Andromeda Galaxy
论文作者
论文摘要
巨大的恒星流（GSS）是仙女座星系（M31）的光环中的突出潮汐特征，代表了卫星银河系的持续破坏。在本文中，我们通过详细的数值模拟对祖细胞系统的潮汐破坏进行了研究。假设流是在M31和矮球的单个合并事件中创建的，其出色的质量为$ 10^{9} m _ {\ odot} $，我们成功地重现了GSS的动力学特性。由于沿流的金属分布已经从观测值（熊猫和Amiga数据集）中得到很好的确定，因此我们使用蒙特卡洛模拟重建矮祖细胞的原始金属性分布。我们发现，一个具有负径向金属梯度的祖细胞矮星系，$Δ$ feH = -0.3 \ pm 0.2 $，在合并中的2.4和2.9 Gyrs之间可重现观察到的GSS属性。我们还表明，观察到的沿流的双峰金属性分布是由独特的合并环境引起的暂时结构，其中两组流星正在朝相反的方向移动，相交以产生峰。
The Giant Stellar Stream (GSS) is a prominent tidal feature in the halo of the Andromeda Galaxy (M31), representing the ongoing destruction of a satellite galaxy. In this paper, we investigate the formation of the GSS through detailed numerical simulations of the tidal disruption of a progenitor system. Assuming that the stream was created in a single merger event between M31 and a dwarf spheroidal galaxy with stellar mass of $10^{9}M_{\odot}$, we successfully reproduce the dynamical properties of the GSS. As the metallicity distribution along the stream has been well determined from the observations (PAndAS and AMIGA data sets), we use Monte Carlo simulations to reconstruct the original metallicity distribution of the dwarf progenitor. We find that a progenitor dwarf galaxy with a negative radial metallicity gradient, $Δ$FeH = -$0.3 \pm 0.2$, reproduces the observed GSS properties at a time between 2.4 and 2.9 Gyrs into the merger. We also show that the observed double peak metallicity distribution along the stream is a transitory structure caused by unique merger circumstances where two groups of streaming stars are moving in opposite directions, intersecting to produce the peaks.
