Mapping a stellar disk into a boxy bulge: The outside-in part of the
  Milky Way bulge formation
  By means of idealized, dissipationless N-body simulations which follow the
formation and subsequent buckling of a stellar bar, we study the
characteristics of boxy/peanut-shaped bulges and compare them with the
properties of the stellar populations in the Milky Way bulge. The main results
of our modeling, valid for the general family of boxy/peanut shaped bulges, are
the following: (i) because of the spatial redistribution in the disk initiated
at the epoch of bar formation, stars from the innermost regions to the outer
Lindblad resonance of the stellar bar are mapped into a boxy bulge; (ii) the
contribution of stars to the local bulge density depends on their birth radius:
stars born in the innermost disk tend to dominate the innermost regions of the
boxy bulge, while stars originating closer to the OLR are preferentially found
in the outer regions of the boxy/peanut structure; (iii) stellar birth radii
are imprinted in the bulge kinematics, the larger the birth radii of stars
ending up in the bulge, the greater their rotational support and the higher
their line-of- sight velocity dispersions (but note that this last trend
depends on the bar viewing angle); (iv) the higher the classical
bulge-over-disk ratio, the larger its fractional contribution of stars at large
vertical distance from the galaxy mid-plane. (ABRIDGED) On the basis of their
chemical and kinematic characteristics, the results of our modeling suggests
that the populations A, B and C, as defined by the ARGOS survey, can be
associated, respectively, with the inner thin disk, to the young thick and to
the old thick disk, following the nomenclature recently suggested for stars in
the solar neighborhood by Haywood et al. (2013).
