Vertical Density Distribution of the Galaxy from Star Count Analysis

Abstract

The five space density distribution D(z) with distance perpendicular to the Galactic plane were combined. The scale heights and the local densities at z = 0 of the thin disk, thick disk, and the halo components were estimated from the nonlinear least square fits of exponential law. The scale heights of the thin disk, thick disk, and the halo components were estimated to be 260±90 pc, 660±220 pc, and 3.6±1.4 kpc, respectively. The density ratio of each components to the thin disk component at the galactic plane, i.e., z=0.0, were also derived as 1:0.07:0.002. Our model fit suggests that the thick disk component has a local density of 6.9% relative to the thin disk.

Keywords

• star count
• stellar content
• galaxy structure