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arXiv · 1711.07493

A Magellanic origin for the Virgo substructure

D. Boubert·V. Belokurov·D. Erkal·G. Iorio
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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.

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D. Boubert, V. Belokurov, D. Erkal, G. Iorio. 2018-10-31. A Magellanic origin for the Virgo substructure. https://doi.org/10.1093/mnras%2Fsty3014

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