CO J = 2 - 1 Emission from Evolved Stars in the Galactic Bulge
arXiv:1407.8453 · doi:10.1088/0004-637X/765/1/20
Abstract
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 (+/- 2.2) x 10^-5 M_Sun/year and a gas-to-dust ratio of 310 (+/- 89). For [SLO2003] A12, we find a gas mass-loss rate of 5.4 (+/- 2.8) x 10^-5 M_Sun/year and a gas-to-dust ratio of 220 (+/- 110). For [SLO2003] A51, we find a gas mass-loss rate of 3.4 (+/- 3.0) x 10^-5 M_Sun/year and a gas-to-dust ratio of 160 (+/- 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.
arXiv comment40 pages, 16 figures, appeared in the 1 March 2013 issue of the Astrophysical Journal
References in corpus (28)
- The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
- The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
- The Spitzer Space Telescope Mission
- The VizieR database of Astronomical Catalogues
- GLIMPSE: I. A SIRTF Legacy Project to Map the Inner Galaxy
- The AKARI/IRC Mid-Infrared All-Sky Survey
- The Submillimeter Array
- Infrared Extinction Toward Nearby Star-Forming Regions
- Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles - II. CO line survey of evolved stars: derivation of mass-loss rate formulae
- Observational m Interstellar Extinction Curves Toward Star-Forming Regions Derived from Spitzer IRS Spectra
- On the reliability of mass-loss-rate estimates for AGB stars
- Probing the mass-loss history of AGB and red supergiant stars from CO rotational line profiles I. Theoretical model -- Mass-loss history unravelled in VY CMa
- The Mass-Loss Return From Evolved Stars to The Large Magellanic Cloud VI: Luminosities and Mass-Loss Rates on Population Scales
- The AGB superwind speed at low metallicity
- 2D Models for Dust-driven AGB Star Winds
- The AST/RO Survey of the Galactic Center Region. I. The Inner 3 Degrees
- The mass-loss return from evolved stars to the Large Magellanic Cloud V. The GRAMS carbon-star model grid
- Point Sources from a Spitzer IRAC Survey of the Galactic Center
- Metallicity of Red Giants in the Galactic Bulge from Near-Infrared Spectroscopy
- Exploring wind-driving dust species in cool luminous giants I. Basic criteria and dynamical models of M-type AGB stars
- The Mass-Loss Return from Evolved Stars to the Large Magellanic Cloud IV: Construction and Validation of a Grid of Models for Oxygen-Rich AGB Stars, Red Supergiants, and Extreme AGB Stars
- Fundamental parameters, integrated RGB mass loss and dust production in the Galactic globular cluster 47 Tucanae
- Fast Winds and Mass Loss from Metal-Poor Field Giants
- Near-IR spectra of ISOGAL sources in the Inner Galactic Bulge
- Three-component modeling of C-rich AGB star winds. II. The effects of drift in long-period variables
- A Catalog of 24um Sources Toward the Galactic Center
- Near-IR spectroscopy of OH/IR stars in the Galactic Centre
- CO in OH/IR stars close to the Galactic centre