The Information Of The Milky Way From 2MASS Whole Sky Star Count: The Structure Parameters

Understand

The Ks band differential star count of the Two Micron All Sky Survey (2MASS) is used to derive the global structure parameters of the smooth components of the Milky Way.

• To avoid complication introduced by other fine structures and significant extinction near and at the Galactic plane, we only consider Galactic latitude |b| > 30 degree data.
• The star count data is fitted with a threecomponent model: double exponential thin disk and thick disk, and a power law decay oblate halo.
• Using maximum likelihood the best-fit local density of thin disk is n0 = 0.030 +- 0.002 stars/pc^3.