A Magellanic origin for the Virgo substructure
  Iorio et al. (2018) mapped out the Milky Way halo using a sample of RR Lyrae
stars drawn from a cross-match of Gaia with 2MASS. We investigate the
significant residual in their model which we constrain to lie at Galactocentric
radii $12<R<27\;\mathrm{kpc}$ and extend over $2600\;\mathrm{deg}^2$ of the
sky. A counterpart of this structure exists in both the Catalina Real Time
Survey and the sample of RR Lyrae variables identified in Pan-STARRS by
Hernitschek et al. (2016), demonstrating that this structure is not caused by
the spatial inhomogeneity of Gaia. The structure is likely the Virgo Stellar
Stream and/or Virgo Over-Density. We show the structure is aligned with the
Magellanic Stream and suggest that it is either debris from a disrupted dwarf
galaxy that was a member of the Vast Polar Structure or that it is SMC debris
from a tidal interaction of the SMC and LMC $3\;\mathrm{Gyr}$ ago. If the
latter then the sub-structure in Virgo may have a Magellanic origin.
