Kinematics and chemical properties of the galaxy in the vicinity of the North Galactic Pole

We have performed a global analysis of the Majewski deep star count survey towards the North Galactic Pole including magnitude, distance, space motions, and metallicity. Principal Component Analysis has been used to visualize the intrinsic stellar distributions of each population in the data set, otherwise unrecognizable. By combining the kinematical, chemical and spatial distributions, it is found that the intrinsic stellar distributions show a significant departure from the continuous trend, thus giving evidence of a discrete galactic thick disk in the Galaxy. The different stellar components and populations are disentangled in an n-dimensional space. The velocity dispersions of the old disk are (sigma(U), sigma(V))=(48+/-5, 23+/-2) km sec(-1). We found an asymmetric drift gradient of -14+/-5 km sec(-1) kpc(-1) for the thick disk. We determined the velocity ellipsoid of halo (sigma(U), sigma(V))=(138+/-11,102+/-9) km sec(-1) with a small retrograde rotation (V-rot=-31+/-10 km/s). A Galactic kinematic model has been built for modeling the data in the vicinity of the North Galactic Pole, the simulated sample has been used to test the viability of the methods. The implications of the results for the models of the thick disk formation are briefly discussed. (C) 1997 American Astronomical Society.