Asymptotic Behavior of the Supersonic Interstellar Gas Flow inGalactic Spiral Density Waves

The supersonic nonlinear gas behavior is studied to describe the gas flow in the galactic spiral density wave. The explicit form of the expression describing a critical amplitude of density wave potential, which separates the supersonic flow from the flow containing a jump between supersonic and subsonic flows is obtained. The latter allows us to define the dependence of perturbed galactic potential, under which the shock can be developed, on the macroscopic equilibrium parameters of the system under study, e.g. a sound speed, an angular velocity of galactic rotation, an angular velocity of `spiral design', etc.