The small boxy/peanut structure of the Milky Way traced by old stars
  We analyse the positions of RR Lyrae stars in the central region of the Milky
Way. In addition to the overall bar shape detected previously, we find evidence
for a peanut shaped structure, in form of overdensities near $\ell=-2$ deg and
$1$ deg at $b\sim-3.5$ deg. The corresponding physical distance between the two
peaks of the peanut is $\sim0.7$ kpc, significantly shorter than that found
from near-IR images (3.3 kpc) and red-clump stars. Qualitatively this is
expected from `fractionation' of bar orbits, which we demonstrate to be matched
in a simulation of an inside-out growing disc subsequently forming a bar.
