Recent measurements suggest that the Large Magellanic Cloud (LMC) may weigh as much as 25\% of the Milky Way. In this work we explore how such a large satellite affects mass estimates of the Milky Way based on equilibrium modelling of the stellar halo or other tracers. In particular, we show that if the LMC is ignored, the Milky Way mass is overestimated by as much as 50\%. This bias is due to the bulk motion in the outskirts of the Galaxy's halo and can be, at least in part, accounted for with a simple modification to the equilibrium modelling. Finally, we show that the LMC has a substantial effect on the orbit Leo I which acts to increase its present day speed relative to the Milky Way. We estimate that accounting for a $1.5\times10^{11} M_\odot$ LMC would lower the inferred Milky Way mass to $\sim10^{12} M_\odot$.

中文翻译：

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银河系质量的平衡模型被 LMC 偏高

最近的测量表明，大麦哲伦星云 (LMC) 的重量可能高达银河系的 25%。在这项工作中，我们基于恒星晕或其他示踪剂的平衡建模探索了如此大的卫星如何影响银河系的质量估计。特别是，我们表明如果忽略 LMC，银河系的质量被高估了 50%。这种偏差是由于星系晕外围的大量运动造成的，并且至少可以部分地通过对平衡模型的简单修改来解释。最后，我们表明 LMC 对 Leo I 轨道有重大影响，这会增加其当前相对于银河系的速度。我们估计，考虑到 $1.5\times10^{11} M_\odot$ LMC 会将推断的银河系质量降低到 $\sim10^{12} M_\odot$。