Program MEGA: stellar counts and galactic models

A comparison of the observed stellar distributions with a three-component model of the Galaxy is presented. The analysis is based on photometric da ta and absolute proper motions obtained in three fields of the program MEGA. Two of the fields are located near the North Galactic Pole and the third field is towards the galactic center. The model assumed considers the Galaxy as composed of the disk, thick disk and spheroid populations. To model the observed color distribution, we consider the main sequence stars and disk red giants as the disk subsystem, white dwarfs, subdwarfs and intermediate giants as the thick disk subsystem and extreme subdwarfs, spheroid giants and horizontal branch stars as the spheroid subsystem. To describe the observed distribution of absolute proper motions, a normal distribution of the spatial velocity components is considered. The da ta were used to improve parameters of spatial and kinematical models of the Galaxy.