1.5. SiO maser sources in the Galactic bulge and a kinematic signature of the bar structure

Abstract

We are studying the kinematic structure of our Galaxy by detecting SiO maser lines around 43 GHz with the Nobeyama 45-m telescope. Till today, about 500 IRAS sources (AGB stars) in the central region of the Galaxy are observed and the radial velocities of about 300 detected sources are obtained. The longitude-velocity map of SiO sources clearly shows a presence of forbidden regions (holes) which are located at the same positions of HI and CO holes. The presence of holes is interpreted as a streaming motions of stars due to a bar structure of the Galactic bulge