论文标题
银河系变形的暗物质光环和孤儿溪流上的大麦芽云的影响
The effect of the deforming dark matter haloes of the Milky Way and the Large Magellanic Cloud on the Orphan-Chenab stream
论文作者
论文摘要
最近已经显示，大型麦哲伦云（LMC）对银河系的恒星光环和恒星流具有重大影响。在这里，我们探讨了银河系的变形和LMC的暗物质光环如何影响恒星流，以及这些影响是否可观察到。特别是，我们专注于特别接近LMC的孤儿 - 章鱼（OC）流，并跨越了银河系的光环的很大一部分。我们使用基本功能扩展代表银河系 - LMC系统，这些功能扩展以$ n $ body模拟捕获其演变。我们介绍了该系统的特性，例如每个星系的密度和力场的演变。 OC流在这种时间依赖性的，变形的电位中进化，我们研究了银河系和LMC的各个矩的影响。我们发现模拟的OC流受到银河系和LMC的变形的强烈影响，并且这种效应比当前的观察误差大得多。特别是，银河系偶极子对溪流的影响最大，其次是LMC的单极和LMC的四极杆的演变。检测这些效果将证实对无碰撞，冷暗物质的关键预测，并将是对替代暗物质和替代重力模型的有力测试。
It has recently been shown that the Large Magellanic Cloud (LMC) has a substantial effect on the Milky Way's stellar halo and stellar streams. Here, we explore how deformations of the Milky Way and LMC's dark matter haloes affect stellar streams, and whether these effects are observable. In particular, we focus on the Orphan-Chenab (OC) stream which passes particularly close to the LMC, and spans a large portion of the Milky Way's halo. We represent the Milky Way--LMC system using basis function expansions that capture their evolution in an $N$-body simulation. We present the properties of this system, such as the evolution of the densities and force fields of each galaxy. The OC stream is evolved in this time-dependent, deforming potential, and we investigate the effects of the various moments of the Milky Way and the LMC. We find that the simulated OC stream is strongly influenced by the deformations of both the Milky Way and the LMC, and that this effect is much larger than current observational errors. In particular, the Milky Way dipole has the biggest impact on the stream, followed by the evolution of the LMC's monopole, and the LMC's quadrupole. Detecting these effects would confirm a key prediction of collisionless, cold dark matter, and would be a powerful test of alternative dark matter and alternative gravity models.
