Modelling the Tucana III stream - a close passage with the LMC
  We present results of the first dynamical stream fits to the recently
discovered Tucana III stream. These fits assume a fixed Milky Way potential and
give proper motion predictions, which can be tested with the upcoming Gaia Data
Release 2. These fits reveal that Tucana III is on an eccentric orbit around
the Milky Way and, more interestingly, that Tucana III passed within 15 kpc of
the Large Magellanic Cloud (LMC) approximately 75 Myr ago. Given this close
passage, we fit the Tucana III stream in the combined presence of the Milky Way
and the LMC. We find that the predicted proper motions depend on the assumed
mass of the LMC and that the LMC can induce a substantial proper motion
perpendicular to the stream track. A detection of this misalignment will
directly probe the extent of the LMC's influence on our Galaxy, and has
implications for nearly all methods which attempt to constraint the Milky Way
potential. Such a measurement will be possible with the upcoming Gaia DR2,
allowing for a measurement of the LMC's mass.
