A 3mm SiO maser survey in the galactic bulge region

Abstract

We have made a blind survey of SiO masers, of the J=2-1 v = 1 transition, toward 106 bright OH/IR stars which have been previously detected in the OH main line at 1662 MHz with the ATCA in the galactic bulge by Sevenster et al (2000) and in the galactic disk at J=1-0 (v = 1 − 2) line by Miyazaki (2001). A comparison with published data shows that new SiO masers are detected for OH/IR stars in the galactic center, suggesting that those stars are undergoing strong mass loss with dense circumstellar envelopes with apparent angular sizes far smaller than the OH maser shell as obtained by interferometric observations. At the moment, our detection rate is about 23% and it may be increased when the project is completed.