A dynamical model of the Galaxy

A series of dynamical models of the Galaxy is constructed assuming that the entire disk is near the gravitational-stability limit. This imposes constraints on the dynamical and kinematic parameters of the main subsystems (the disk, bulge, and halo). The disk surface density in the solar neighborhood should not exceed 58 Mcircle dot/ pc(2). Further, we find that the observed local decrease in the rotational velocity at 6 kpc less than or similar to r less than or similar to 10 kpc is not associated with details of the radial distribution of matter in the Galaxy and instead results from dynamical processes or some other factors responsible for noncircular motions. It follows from the presence of a long-lived bar and the observed distribution of the stellar-velocity dispersion that the central maximum in the rotation curve at radius r similar or equal to 300 pc cannot be associated with a very concentrated bulge core. The best agreement between the observational data and the parameters of the dynamical models is achieved for a radial disk scale length of L similar or equal to 3 kpc. The relative contribution of the disk to the circular rotational velocity at r = 2.2L is 73%. (C) 2003 MAIK 'Nauka/Interperiodica".