Kinematic distances of Galactic sources in the outer Galaxy <br /><br />
have still uncertainty because of a poor Galactic rotation <br /><br />
curve. Actually the kinematic distance of Galactic star <br /><br />
forming region of W3(OH) was thought to be about 4 kpc from the sun. <br /><br />
We carried out an annual parallax measurement for water <br /><br />
masers in W3(OH) by the phase-referencing VLBI astrometry.<br /><br />
We measured non-linear absolute proper motions relative to an <br /><br />
adjacent extragalactic continuum source and determined its <br /><br />
distance of 2.04+/-0.07 kpc by the parallax. <br /><br />
We think that a difference between kinematic and parallax <br /><br />
distance is caused by a peculiar motion of W3(OH), probably <br /><br />
it is a density wave in the Perseus arm.<br /><br />
<br /><br />
We also found that the water masers formed a \\\"polar cup\\\" <br /><br />
structure and showed a collimated bipolar outflow with <br /><br />
rotating which predicts by the MHD (Magneto-Hydro-Dynamics) theory. <br /><br />
Unfortunately this was not a polarimetric observation, <br /><br />
however the possibility of the MHD outflow will be discussed.<br /><br />