A Magellanic origin for the Virgo substructure

Abstract

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.

9 pages, 7 figures, accepted to MNRAS 31/10/2018

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Cited by in corpus (5)

• Discovery of distant RR Lyrae stars in the Milky Way using DECam
• The Milky Way's stellar streams and globular clusters do not align in a Vast Polar Structure
• Identifying RR Lyrae Variable Stars in Six Years of the Dark Energy Survey
• The Virgo Overdensity Explained
• GSE vs. LMC: reshaping of radially biased stellar haloes by satellites