OUR MILKY WAY AS A PURE-DISK GALAXY—A CHALLENGE FOR GALAXY FORMATION

@article{Shen2010OURMW,
  title={OUR MILKY WAY AS A PURE-DISK GALAXY—A CHALLENGE FOR GALAXY FORMATION},
  author={Juntai Shen and Robert Michael Rich and John Kormendy and Christian D. Howard and Roberto De Propris and Andrea M. Kunder},
  journal={The Astrophysical Journal Letters},
  year={2010},
  volume={720},
  pages={L72 - L76}
}
Bulges are commonly believed to form in the dynamical violence of galaxy collisions and mergers. Here, we model the stellar kinematics of the Bulge Radial Velocity Assay (BRAVA) and find no sign that the Milky Way contains a classical bulge formed by scrambling pre-existing disks of stars in major mergers. Rather, the bulge appears to be a bar seen somewhat end-on, as hinted from its asymmetric boxy shape. We construct a simple but realistic N-body model of the Galaxy that self-consistently… 

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References

SHOWING 1-10 OF 45 REFERENCES

Kinematics of Extragalactic Bulges: Evidence that some Bulges are Really Disks

Recent wor& on the dynamics of galaxy bulges has been dominated by two themes. (1) Bulges share the richness in kinematic structure that is currently being discovered in elliptical galaxies. This

DETECTION OF A PSEUDOBULGE HIDDEN INSIDE THE “BOX-SHAPED BULGE” OF NGC 4565

Numerical simulations show that box-shaped bulges of edge-on galaxies are not bulges: they are bars seen side-on. Therefore, the two components that are seen in edge-on Sb galaxies such as NGC 4565

The Bulge Radial Velocity Assay: Techniques and a Rotation Curve

We are undertaking a large-scale radial velocity survey of the Galactic bulge that uses M giant stars selected from the Two Micron All Sky Survey catalog as targets for the Cerro Tololo

The formation of disc galaxies in a ΛCDM universe

We study the formation of disc galaxies in a fully cosmological framework using adaptive mesh refinement simulations. We perform an extensive parameter study of the main subgrid processes that

Spiral arms, bar shape and bulge microlensing in the Milky Way

A new model for the luminosity distribution in the inner Milky Way is found, using a non-parametric penalized maximum-likelihood algorithm to deproject a dereddened COBE/ DIRBE L-band map of the

A dynamical instability of bars in disk galaxies

STRONG, rapidly rotating, persistent bars readily form in numerical simulations of initially axisymmetric disk galaxies1–4. The global dynamical instability responsible for this behaviour is a great

Three-dimensional Simulations of the Chemical and Dynamical Evolution of the Galactic Bulge

A three-dimensional, hydrodynamical, N-body model for the formation of the Galaxy is presented, with special attention paid to the formation of the bulge component. Since none of the previous

Age and Metallicity Distribution of the Galactic Bulge from Extensive Optical and Near-IR Stellar Photometry

We present a new determination of the metallicity distribution, age, and luminosity function of the Galactic bulge stellar population. By combining near-IR data from the 2MASS survey, from the SOFI

Modeling the Galactic Bar Using Red Clump Giants

The color-magnitude diagrams of ~7 × 105 stars obtained for 12 fields across the Galactic bulge with the Optical Gravitational Lensing Experiment project reveal a well-defined population of bulge red

Secular Evolution and the Formation of Pseudobulges in Disk Galaxies

▪ Abstract The Universe is in transition. At early times, galactic evolution was dominated by hierarchical clustering and merging, processes that are violent and rapid. In the far future, evolution