Mass Loss from Galactic Bulge AGB stars Margaret Meixner (STScI/ visiting Scientist at Harvard-Smithsonian CfA) Nimesh Patel, Dave Riebel, Ben Sargent, Sundar Srinivasan, Ken Young

Why Galactic Bulge? Known Distance: 8 kpc (Reid 1993) Extreme environment High metallicity: peak at -0.3, but wide range: -1<[Fe/H]<1 ISOGal studies reveal a population of AGB star candidates suitable for followup (Omont et al.) Prior studies show that all AGB stars in bulge are oxygen rich, with silicate dust features (Blommaert et al.)

ISOGal sample: spectroscopy of 107 candidate AGB stars Schulteis et al. 2003

Metallicity of Bulge ISOGal sample Solar neigh. Schulteis et al. 2003

Mass Loss rate from IR Schulteis et al. 2003

SMA project: Use SMA to spatially filter the foreground CO cloud emission, and detect the point source AGB molecular winds of Galactic Bulge AGB stars. Use extended SMA configuration, and observe two AGB stars per track. Goal: to measure gas mass-loss rates, compare to dust mass-loss rates and estimate dust to gas mass ratios Data taken last week…

Vexp V0 Vexp Vexp Vexp Jy V0+Vexp V0-Vexp V0 V0-Vexp V0 V0+Vexp The other attractive aspect of evolved stars are their simplicity. The channel maps of evolved stars reveal their 3 dimensional structure. Each slice acts as successive cross-cuts through the circumstellar envelope of the star. I’ll spend the rest of my talk on more recent results pursued by myself with my students. I will be showing a number of channel maps for this data Set and this slide V0+Vexp V0+Vexp V0-Vexp V0

Mass Loss rates from CO Beam size CO abundance Distance Velocity integrated intensity Knapp & Morris (1985) Ramstedt et al. (2008)

Prior work: CO detected in Galactic AGB stars/ OH-IR stars: Winnberg et al. 2009

CO detected in Galactic AGB stars/ OH-IR stars: OH0.3-0.2 Winnberg et al. 2009

CO detected in Galactic AGB stars/ OH-IR stars: OH 359.762 Winnberg et al. 2009

Our SMA sample

Galactic Bulge: A12, OH 359.77+0.08

Galactic Bulge: A12, OH 359.77+0.08

Galactic Bulge: A51, OH 359.681-0.095

Galactic Bulge: A51, OH 359.681-0.095

Preliminary results from SMA sample

Future Prospects Continue this galactic bulge project to collect larger numbers and statistics This project demonstrates an approach that could be used for LMC and SMC AGB samples, but with ALMA