Equilibrium models of the Milky Way mass are biased high by the LMC. (arXiv:2001.11030v1 [astro-ph.GA])

Equilibrium models of the Milky Way mass are biased high by the LMC. (arXiv:2001.11030v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Erkal_D/0/1/0/all/0/1">Denis Erkal</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Belokurov_V/0/1/0/all/0/1">Vasily Belokurov</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Parkin_D/0/1/0/all/0/1">Daniel L. Parkin</a>

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 $1.5times10^{11} M_odot$ LMC
would lower the inferred Milky Way mass to $sim10^{12} M_odot$.

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