The Clouds are breaking: tracing the Magellanic system with Gaia DR1
  Mira variables
  We exploit the first data release from the Gaia mission to identify candidate
Mira variables in the outskirts of the Magellanic Clouds. The repeated
observations of sources during the initial phase of the Gaia mission is used to
identify stars that show signs of variability. This variability information,
combined with infrared photometry from 2MASS and WISE, allows us to select a
clean sample of giants in the periphery of the LMC. We find evidence for Miras
surrounding the LMC out to ~20 deg in all directions, apart from the North-West
quadrant. Our sample does not generally follow the gas distribution of the
Magellanic system; Miras are notably absent in the gaseous bridge between the
LMC and SMC, but they are likely related to the stellar RR Lyrae bridge
reported by Belokurov et al. (2016). The stellar stream discovered by Mackey et
al. (2016) to the North of the LMC is almost perfectly delineated by our Mira
variables, and likely extends further East toward the Galactic plane. The
presence of an intermediate-age population in this stream advocates an LMC disc
origin. We also find a significant excess of Miras to the East of the LMC;
these more diffusely distributed stars are likely stripped SMC stars due to
interactions with the LMC. Miras are also identified in regions of the sky away
from the Clouds; we locate stars likely associated with known massive
substructures, and also find potential associations with stripped SMC debris
above the Galactic plane.
