A new model for the Milky Way bar. (5th March 2015)

• Record Type: Journal Article
• Authors: Wang, Yougang; Zhao, Hongsheng; Mao, Shude; Rich, R. M.
• Editors: Montmerle, Thierry
• Is Part Of: Proceedings of the International Astronomical Union. Volume 10:Number H16(2012)Highlights
• Page Start: 350
• Page End: 350
• Publication Date: 2015-03-05
• Subjects: Galaxy: bulge - Galaxy: centre - Galaxy: kinematics and dynamics; Astronomy -- Congresses; Astronomy -- Periodicals; 520
• DOI: 10.1017/S1743921314011223
• Languages: English
• ISSNs: 1743-9213

Abstract

Abstract: We use Schwarzschild's orbit-superposition technique to construct self-consistent models of the Galactic bar. Using χ 2 minimisation, we find that the best-fit Galactic bar model has a pattern speed Ωp =60 km s −1 kpc −1, disk mass Md =1.0×10 11 M⊙ and bar angle θbar =20° for an adopted bar mass Mbar =2×10 10 M⊙ . The model can reproduce not only the three-dimensional and projected density distributions but also velocity and velocity dispersion data from the BRAVA survey. We also predict the proper motions in the range l =[−12°, 12°], b =[−10°, 10°], which appear to be higher than observations in the longitudinal direction. The model is stable within a timescale of 0.5 Gyr, but appears to deviate from steady-state on longer timescales. Our model can be further tested by future observations such as those from GAIA.