The Structure of the Milky Way's Bar Outside the Bulge
  While it is incontrovertible that the inner Galaxy contains a bar, its
structure near the Galactic plane has remained uncertain, where extinction from
intervening dust is greatest. We investigate here the Galactic bar outside the
bulge, the long bar, using red clump giant (RCG) stars from UKIDSS, 2MASS, VVV,
and GLIMPSE. We match and combine these surveys to investigate a wide area in
latitude and longitude, |b|<9deg and |l|<40deg. We find: (1) The bar extends to
l~25deg at |b|~5deg from the Galactic plane, and to l~30deg at lower latitudes.
(2) The long bar has an angle to the line-of-sight in the range (28-33)deg,
consistent with studies of the bulge at |l|<10deg. (3) The scale-height of RCG
stars smoothly transitions from the bulge to the thinner long bar. (4) There is
evidence for two scale heights in the long bar. We find a ~180pc thin bar
component reminiscent of the old thin disk near the sun, and a ~45pc super-thin
bar component which exists predominantly towards the bar end. (5) Constructing
parametric models for the RC magnitude distributions, we find a bar half length
of 5.0+-0.2kpc for the 2-component bar, and 4.6+-0.3kpc for the thin bar
component alone. We conclude that the Milky Way contains a central box/peanut
bulge which is the vertical extension of a longer, flatter bar, similar as seen
in both external galaxies and N-body models.
