Modeling of Spiral Structure in a Multi-Component Milky~Way-Like Galaxy
  Using recent observational data, we construct a set of multi-component
equilibrium models of the disk of a Milky Way-like galaxy. The disk dynamics
are studied using collisionless-gaseous numerical simulations, based on the
joined integration of the equations of motion for the collision-less particles
using direct integration of gravitational interaction and the gaseous
SPH-particles. We find that after approximately one Gyr, a prominent central
bar is formed having a semi-axis length of about three kpc, together with a
multi-armed spiral pattern represented by a superposition of $m=$ 2-, 3-, and
4-armed spirals. The spiral structure and the bar exist for at least 3 Gyr in
our simulations. The existence of the Milky Way bar imposes limitations on the
density distributions in the subsystems of the Milky Way galaxy. We find that a
bar does not form if the radial scale length of the density distribution in the
disk exceeds 2.6 kpc. As expected, the bar formation is also suppressed by a
compact massive stellar bulge. We also demonstrate that the maximum value in
the rotation curve of the disk of the Milky Way galaxy, as found in its central
regions, is explained by non-circular motion due to the presence of a bar and
its orientation relative to an observer.
