SiO Masers in the Galactic Bulge and Disk: Kinematics from the BAaDE Survey

We present the first results from the Bulge Asymmetries and Dynamic Evolution (BAaDE) survey. Though only a subset of the complete survey (similar to 2700 out of similar to 20,000 final sources), our data comprise the largest radio kinematic survey to date of stellar SiO masers observed toward the Galactic bulge and plane from -15 degrees < l < + 12 degrees and -6 degrees < b < + 6 degrees Our sources include a substantial number of line-of-sight velocities in high extinction regions within +/- 1 degrees of the Galactic plane. When matched with 2MASS(4) photometry, our radio-detected sample lies significantly brighter than and redward of the first red giant branch tip, reaching extremes of (J-Ks) 0 > 8, colors consistent with Mira variables and mass-losing AGB stars. We see a clean division into two kinematic populations: a kinematically cold (sigma similar to 50 km s(-1)) population that we propose is in the foreground disk, consisting of giants with 2MASS Ks < 5.5, and a kinematically hot (sigma similar to 100 km s(-1)) candidate bulge/ bar population for most giants with Ks > 5.5. Only the kinematically hot giants with Ks > 5.5 include the reddest stars. Adopting 8.3 kpc to the Galactic center, and correcting for foreground extinction, we find that most of the sources have Mbol similar to -5, consistent with their being luminous and possibly intermediate-age AGB stars. We note some tension between the possible intermediate age of the kinematically hot population, and its high-velocity dispersion compared to the disk.