SPIRAL-VORTEX STRUCTURE IN THE GASEOUS DISKS OF GALAXIES

General ideas, as well as experimental and theoretical efforts concern ing the prediction and discovery of new structures in the disks of spi ral galaxies - giant anticyclones - are reviewed. A crucial point is t he development of a new method to restore the full vector velocity fie ld of the galactic gas from the line-of-sight velocity field. This met hod can be used to get self-consistent solutions for the following pro blems: 1) determination of non-circular velocities associated with spi ral-vortex structure; 2) determination of fundamental parameters of th is structure: pattern speed, corotation radius, location of giant anti cyclones; 3) refinement of galactic rotation curves taking into accoun t regular non-circular motion in the spiral density wave, which makes it possible to build more accurate models of the mass distribution in the galaxy; 4) refinement of parameters of the rotating gaseous disk: inclination angle, center of rotation and position angle of the major dynamical aids, systematic velocity. The method is demonstrated using the restoration of the velocity field of the galaxy NGC 157 as an exam ple. Results for this and some other spiral galaxies suggest that gian t anticyclones are a universal property of galaxies with grand design structure.