VVV Survey Near-Infrared Photometry of Known Bulge RR Lyrae stars: the
  Distance to the Galactic Center and Absence of a Barred Distribution of the
  Metal-Poor Population
  We have combined optical and near-infrared data of known RR Lyrae (RRL) stars
in the bulge in order to study the spatial distribution of its metal-poor
component by measuring precise reddening values and distances of 7663
fundamental-mode RRL stars with high-quality photometry. We obtain a distance
to the Galactic center of R0 = 8.33 +/- 0.05 +/- 0.14 kpc. We find that the
spatial distribution of the RRL stars differs from the structures traced by the
predominantly metal-rich red clump (RC) stars. Unlike the RC stars, the RRL
stars do not trace a strong bar, but have a more spheroidal, centrally
concentrated distribution, showing only a slight elongation in its very center.
We find a hint of bimodality in the density distribution at high southern
latitudes (b < -5), which needs to be confirmed by extending the areal coverage
of the current census. The different spatial distributions of the metal-rich
and metal-poor stellar populations suggest that the Milky Way has a composite
bulge.
