The Pisces Plume and the Magellanic Wake
  Using RR Lyrae stars in the Gaia Data Release 2 and Pan-STARRS1 we study the
properties of the Pisces Overdensity, a diffuse sub-structure in the outer halo
of the Milky Way. We show that along the line of sight, Pisces appears as a
broad and long plume of stars stretching from 40 to 110 kpc with a steep
distance gradient. On the sky Pisces's elongated shape is aligned with the
Magellanic Stream. Using follow-up VLT FORS2 spectroscopy, we have measured the
velocity distribution of the Pisces candidate member stars and have shown it to
be as broad as that of the Galactic halo but offset to negative velocities.
Using a suite of numerical simulations, we demonstrate that the structure has
many properties in common with the predicted behaviour of the Magellanic wake,
i.e. the Galactic halo overdensity induced by the in-fall of the Magellanic
Clouds.
