SiO Maser Survey off the Galactic Plane: A Signature of Streaming Motion
  A group of Mira variables in the solar neighborhood show unusual spatial
motion in the Galaxy. To study this motion in a much larger scale in the
Galaxy, we newly surveyed 134 evolved stars off the Galactic plane by SiO maser
lines, obtaining accurate radial velocities of 84 detected stars. Together with
the past data of SiO maser sources, we analyzed the radial velocity data of a
large sample of sources distributing in a distance range of about 0.3 -- 6 kpc
in the first Galactic quadrant. At the Galactic longitudes between 20 and 40
deg, we found a group of stars with large negative radial velocities, which
deviate by more than 100 km s^{-1} from the Galactic rotation. We show that
these deviant motions of maser stars are created by periodic gravitational
perturbation of the Bulge bar, and that the effect appears most strongly at
radii between corotation and outer Lindblad resonances. The resonance effect
can explain the displacement of positions from the Galactic plane as well.
