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

Abstract

We present the first results from the BAaDE (Bulge Asymmetries and Dynamic Evolution) survey. Though only a subset of the complete survey ($\sim$2700 out of $\sim$20000 final sources), our data comprise the largest radio kinematic survey to date of stellar SiO masers observed toward the Galactic bulge and plane from $-15^{\circ }<l<+12^{\circ }$ and $-6^{\circ }<b<+6^{\circ }$. Our sources include a substantial number of line-of-sight (LoS) velocities in high extinction regions within $\pm 1^{\circ }$ of the Galactic plane. When matched with 2MASS photometry, our radio-detected sample lies significantly brighter than and red-ward 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 ($\sigma \sim 50\mathrm{km}\mathrm{se}{\mathrm{c}}^{-1}$) population that we propose is in the foreground disk, consisting of giants with 2MASS $Ks<5.5$, and a kinematically hot ($\sigma \sim 100\mathrm{km}\mathrm{se}{\mathrm{c}}^{-1}$) 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 $M_{bol}\sim -5$, consistent with their being luminous, and possibly intermediate age, AGB stars. We note some tension between the possibly intermediate age of the kinematically hot population, and its high velocity dispersion compared to the disk.

arXiv comment18 pages, 17 Figures; Submitted to ApJ (Accepted May 7)

References in corpus (48)

• The Galaxy in Context: Structural, Kinematic and Integrated Properties
• An Update on Monitoring Stellar Orbits in the Galactic Center
• Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. V. Evidence for a wide age distribution and a complex MDF
• Age and Metallicity Distribution of the Galactic Bulge from Extensive Optical and Near-IR Stellar Photometry
• Evolution of the Bar Fraction in COSMOS: Quantifying the Assembly of the Hubble Sequence
• Secular Evolution in Disk Galaxies
• Our Milky Way as a Pure-Disk Galaxy -- A Challenge for Galaxy Formation
• ARGOS III: Stellar Populations in the Galactic Bulge of the Milky Way
• The Bulge Radial Velocity Assay (BRAVA): II. Complete Sample and Data Release
• Modelling the Galactic Bar Using Red Clump Giants
• ARGOS IV: The Kinematics of the Milky Way Bulge
• Chemical evolution of the Galactic bulge as traced by microlensed dwarf and subgiant stars. VI. Age and abundance structure of the stellar populations in the central sub-kpc of the Milky Way
• Bar Diagnostics in Edge-On Spiral Galaxies. III. N-Body Simulations of Disks
• Made-to-Measure models of the Galactic Box/Peanut bulge: stellar and total mass in the bulge region
• Stellar Proper Motions in the Galactic Bulge from deep HST ACS/WFC Photometry
• The structure of the Galactic bar
• The GIRAFFE Inner Bulge Survey (GIBS) III. Metallicity distributions and kinematics of 26 Galactic bulge fields
• HST/WFPC2 proper motions in two bulge fields: kinematics and stellar population of the Galactic bulge
• The GIRAFFE Inner Bulge Survey (GIBS). I. Survey Description and a kinematical map of the Milky Way bulge
• The First Detection of Blue Straggler Stars in the Milky Way Bulge
• Infrared stellar populations in the central parts of the Milky Way galaxy
• The Bulge Radial Velocity Assay (BRAVA): I. Techniques and a Rotation Curve
• Before the Bar: Kinematic Detection of A Spheroidal Metal-Poor Bulge Component
• The Age and Structure of the Galactic Bulge from Mira Variables
• 2D kinematic signatures of boxy/peanut bulges
• A parametric description of the 3D structure of the Galactic Bar/Bulge using the VVV survey
• The Apache Point Observatory Galactic Evolution Experiment: First Detection of High Velocity Milky Way Bar Stars
• Stellar Ages through the Corners of the Boxy Bulge
• Young stars in an old bulge: a natural outcome of internal evolution in the Milky Way
• 86 GHz SiO maser survey of late-type stars in the Inner Galaxy. I. Observational data
• SiO Maser Survey of IRAS Sources in the Inner Galactic Disk
• Globular Clusters and the Mira Period-Luminosity Relation
• Metallicity and kinematics of the bar in-situ
• Dynamics of the Galactic Bulge using Planetary Nebulae
• Hiding its age: the case for a younger bulge
• SiO Maser Survey of the Large-Amplitude Variables in the Galactic Center
• Lifting the Dusty Veil With Near- and Mid-Infrared Photometry: III. Two-Dimensional Extinction Maps of the Galactic Midplane Using the Rayleigh-Jeans Color Excess Method
• Kinematics in the Galactic Bulge with APOGEE: II. High-Order Kinematical Moments and Comparison to Extragalactic Bar Diagnostics
• Near-Infrared Variability Study of the Central 2.3 arcmin x 2.3 arcmin of the Galactic Centre II. Identification of RR Lyrae Stars in the Milky Way Nuclear Star Cluster
• Correlations between kinematics and metallicity in the Galactic bulge: a review
• MSX versus IRAS Two-Color Diagrams and the CSE-Sequence of Oxygen-Rich Late-Type Stars
• SiO Maser Survey of the Inner Bar of the Galactic Bulge
• Detections of SiO Masers from the Large-Amplitude Variables in the Galactic Nuclear Disk
• Spatial Diffusion of Stars in the Inner Galactic Bulge
• Predicted Stellar Kinematics of a Kiloparsec-Scale Nuclear Disc (or Ring) in the Milky Way
• Chemical abundances and ages of the bulge stars in APOGEE high-velocity peaks
• Age and metallicity gradients in the Galactic Bulge - A differential study using HST/WFPC2
• Red clump distances to the inner Galactic structures

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• A KMOS survey of the nuclear disk of the Milky Way I: Survey design and metallicities
• Radio Stars: from kHz to THz
• Carbon- and Oxygen-rich Asymptotic Giant Branch (AGB) stars in the Bulge Asymmetries and Dynamical Evolution (BAaDE) survey
• Understanding the velocity distribution of the Galactic Bulge with APOGEE and Gaia
• Positional Offsets Between SiO Masers in Evolved Stars and their Cross-Matched Counterparts
• Ground Vibrational State SiO Emission in the VLA BAaDE Survey
• Infrared color separation between thin-shelled oxygen-rich and carbon-rich AGB stars
• Spectroscopic Observations of Obscured Populations in the Inner Galaxy: 2MASS-GC02, Terzan 4, and the 200 km/s stellar peak
• Characterizing the Evolved Stellar Population in the Galactic Foreground I: Bolometric Magnitudes, Spatial Distribution and P-L Relations
• Long-period maser-bearing Miras in the Galactic center: period-luminosity relations and extinction estimates