We observe a sample of 8 evolved stars in the Galactic Bulge in the CO J=2–1 line using the Submillimeter Array ( SMA ) with angular resolution of 1–4 arcseconds .
These stars have been detected previously at infrared wavelengths , and several of them have OH maser emission .
We detect CO J=2–1 emission from three of the sources in the sample : OH 359.943 +0.260 , [ SLO2003 ] A12 , and [ SLO2003 ] A51 .
We do not detect the remaining 5 stars in the sample because of heavy contamination from the galactic foreground CO emission .
Combining CO data with observations at infrared wavelengths constraining dust mass loss from these stars , we determine the gas-to-dust ratios of the Galactic Bulge stars for which CO emission is detected .
For OH 359.943 +0.260 , we determine a gas mass-loss rate of 7.9 ( \pm 2.2 ) \times 10 ^ { -5 } { M } _ { \sun } { yr } ^ { -1 } and a gas-to-dust ratio of 310 ( \pm 89 ) .
For [ SLO2003 ] A12 , we find a gas mass-loss rate of 5.4 ( \pm 2.8 ) \times 10 ^ { -5 } { M } _ { \sun } { yr } ^ { -1 } and a gas-to-dust ratio of 220 ( \pm 110 ) .
For [ SLO2003 ] A51 , we find a gas mass-loss rate of 3.4 ( \pm 3.0 ) \times 10 ^ { -5 } { M } _ { \sun } { yr } ^ { -1 } and a gas-to-dust ratio of 160 ( \pm 140 ) , reflecting the low quality of our tentative detection of the CO J=2–1 emission from A51 .
We find the CO J=2–1 detections of OH/IR stars in the Galactic Bulge require lower average CO J=2–1 backgrounds .