The Orbital Histories of Magellanic Satellites Using Gaia DR2 Proper
  Motions
  With the release of Gaia DR2, it is now possible to measure the proper
motions (PMs) of the lowest mass, ultra-faint satellite galaxies in the Milky
Way's (MW) halo for the first time. Many of these faint satellites are posited
to have been accreted as satellites of the Magellanic Clouds (MCs). Using their
6-dimensional phase space information, we calculate the orbital histories of 13
ultra-faint satellites and five classical dwarf spheroidals in a combined
MW+LMC+SMC potential to determine which galaxies are dynamically associated
with the MCs. These 18 galaxies are separated into four classes: i.) long-term
Magellanic satellites that have been bound to the MCs for at least the last two
consecutive orbits around the MCs (Carina 2, Carina 3, Horologium 1, Hydrus 1);
ii.) Magellanic satellites that were recently captured by the MCs $<$ 1 Gyr ago
(Reticulum 2, Phoenix 2); iii.) MW satellites that have interacted with the MCs
(Sculptor 1, Tucana 3, Segue 1); and iv.) MW satellites (Aquarius 2, Canes
Venatici 2, Crater 2, Draco 1, Draco 2, Hydra 2, Carina, Fornax, Ursa Minor).
Results are reported for a range of MW and LMC masses. Contrary to previous
work, we find no dynamical association between Carina, Fornax, and the MCs.
Finally, we determine that the addition of the SMC's gravitational potential
affects the longevity of satellites as members of the Magellanic system
(long-term versus recently captured), but it does not change the total number
of Magellanic satellites.
