Abstract:
The results of N-body experiments modelling the disc of our Galaxy are presented. We used the suggestion, that the disc at all radii is on the threshold of gravitational stability. This suggestion sets some limits on dynamic and kinematic parameters of the main subsystems of the Galaxy (disc, bulge and halo). In the solar neighborhood the upper bound of surface density is calculated as 58M_opc^-2. We came to the conclusion, that the local minimum of the rotation curve in the region 6kpc < r < 10kpc is not the result of mass distribution, but may arise from local dynamic processes or another factors, that can cause non-circular motion. Using the observed stellar velocity dispersion and suggesting that the bar in the Milky Way is long-living, we conclude that the central maximum on the rotation curve cannot be explained by the strongly concentrated core of the bulge. The best agreement between model parameters and observed data is reached for an exponential scale length of the disc of 3kpc. The total disc mass does not exceed M_d=4.5•10¹⁰M_o. The relative halo mass in the sphere r < R_o = 8kpc should exceed 80% of disc mass.

Full printable article (PDF)