ARGOS IV: The Kinematics of the Milky Way Bulge
  We present the kinematic results from our ARGOS spectroscopic survey of the
Galactic bulge of the Milky Way. Our aim is to understand the formation of the
Galactic bulge. We examine the kinematics of about 17,400 stars in the bulge
located within 3.5 kpc of the Galactic centre, identified from the 28,000 star
ARGOS survey. We aim to determine if the formation of the bulge has been
internally driven from disk instabilities as suggested by its boxy shape, or if
mergers have played a significant role as expected from Lambda CDM simulations.
From our velocity measurements across latitudes b = -5 deg, -7.5 deg and -10
deg we find the bulge to be a cylindrically rotating system that transitions
smoothly out into the disk. Within the bulge, we find a kinematically distinct
metal-poor population ([Fe/H] < -1.0) that is not rotating cylindrically. The
5% of our stars with [Fe/H] < -1.0 are a slowly rotating spheroidal population,
which we believe are stars of the metal weak thick disk and halo which
presently lie in the inner Galaxy. The kinematics of the two bulge components
that we identified in ARGOS paper III (mean [Fe/H] = -0.25 and [Fe/H] = +0.15,
respectively) demonstrate that they are likely to share a common formation
origin and are distinct from the more metal poor populations of the thick disk
and halo which are colocated inside the bulge. We do not exclude an underlying
merger generated bulge component but our results favour bulge formation from
instabilities in the early thin disk.
