Astrometry of galactic star-Forming region g48.61+0.02 with VERA

Abstract

We performed the astrometry of H2O masers in the Galactic star-forming region G48.61+0.02 with the VLBI Exploration of Radio Astrometry (VERA). We derived a trigonometric parallax of 199±7μas, which corresponds to a distance of 5.03±0.19 kpc. The distance to G48.61+0.02 is about half of its far kinematic distance, whichvwas often assumed previously. This distance places G48.61+0.02 in the Sagittarius-Carina arm, and near to the vactive star-forming region and the supernova remnant W 51. We also obtained the three-dimensional motion of G48.61+0.02, and found that it has a large peculiar motion of 40±5 kms-1. This peculiar motion would have originated along with multiple supernovae explosions in W 51, or streaming motion across the Sagittarius-Carina arm. © 2011. Astronomical Society of Japan.