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The inner structure of the Milky Way Galaxy. Yougang Wang (NAOC) & Shude Mao(NAOC) Hongsheng Zhao (St.Andrews) Michael Rich (UCLA) et al. Outline. Background Schwarzschild’s orbit-superposition technique Results Summaries and future studies. Milky Way Galaxy. Bar. Disk.
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The inner structure of the Milky Way Galaxy Yougang Wang (NAOC) & Shude Mao(NAOC) Hongsheng Zhao (St.Andrews) Michael Rich (UCLA) et al.
Outline • Background • Schwarzschild’s orbit-superposition technique • Results • Summaries and future studies
Milky Way Galaxy Bar Disk Nuclear Bulge Halo Globular Clusters
Background I: Observations • Optical Gravitational Lensing Experiment (OGLE) (OGLE II)5080236 prop motion • Red Clump from OGLE-III OGLE 1.3m telescope at the Las Campanas Observatory in Chile.
Background II: Observations • Bulge Radial Velocity Assay (BRAVA) Using M red giant stars selected from 2MASS catalog and Cerro Tololo Inter-Americal Observatory 4 m Hydra multiobject spectrograph ~3300 radial velocity along the major axis and minor axis of the bulge
Background III: model • Zhao (1996) used the Schwarzschild’s method constructed a self-consistent model • Hafner et al.(2000) only several data fit well • Bissantz et al.(2000) made-to-measure method
The aim of our studies • Using the Schwarzschild’s orbit-superposition technique to construct the self-consistent and stable model of the Galactic bar • In model constraints, adding the current available data (COBE,BRAVA ).
Model of the Milky Way • Bar + bulge • MN disk
Density Poisson Equation Potential Initial Conditions for orbit library Orbit library Least Square Method, adding the data constraints Weights Initial Conditions for N-body NBODY code End State Analysis (anisotropy, energy distribution, triaxiality, etc.)
Self-consistency of the model 3d-density,2d-density Velocity and velocity dispersion alone both the major and minor axes of the bar 2d-density 3d-density
degeneracy between the patter speed of the bar and the disk mass
Summaries and Future studies • Self-consistent model and stable dynamical model,omp=-60km/s/kpc, Mdisk=1011Msun BA=20o • New data constraints • Full model for the Milky Way bar+bulge+disk+dark matter halo