A new model for the Milky Way bar

Yougang Wang*, Hongsheng Zhao, Shude Mao, R. M. Rich

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Citations (Scopus)

Abstract

We use Schwarzschild's orbit-superposition technique to construct self-consistent models of the Galactic bar. Using χ 2 minimization, we find that the best-fitting Galactic bar model has a pattern speed Ω p = 60kms -1kpc -1, disc mass M d = 1.0 × 10 11M and bar angle θ bar = 20° for an adopted bar mass M bar = 2 × 10 10M . The model can reproduce not only the three-dimensional and projected density distributions but also velocity and velocity dispersion data from the Bulge Radial Velocity Assay (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 time-scale of 0.5 Gyr, but appears to deviate from steady state on longer time-scales. Our model can be further tested by future observations such as those from GAIA.

Original languageEnglish
Pages (from-to)1429-1440
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Volume427
Issue number2
DOIs
Publication statusPublished - 1 Dec 2012

Keywords

  • Galaxy: bulge
  • Galaxy: centre
  • Galaxy: formation
  • Galaxy: kinematics and dynamics
  • Galaxy: nucleus
  • Galaxy: structure

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