A Method for Reconstructing the Full Vector Velocity Field in the Gaseous Disks of Spiral Galaxies

A method is proposed for reconstructing the full vector velocity eld (i.e., the three velocity components) in the gaseous disks of spiral galaxies from observed radial velocities. The method is based on Fourier analysis of the observed velocity eld and interpretation of the resulting Fourier harmonics in the framework of a model accounting for motion in the spiral arms. The model is based on the concept of galactic spirals as density waves. The proposed me(hod can be used to (1) nd noncircular velocities associated with spiral-vortex structure; (2) nd fundamental parameters for this structure, such as the angular rotational velocity, the corotation radius, and the location of giant anticyclones; (3) reene the rotation curves of galaxies by taking into account noncircular velocities in spiral density waves, which leads to a more precise determination of the mass distribution in the galaxies; and (4) reene parameters determining the galactic plane: inclination angle, location ot the center of rotation, and the position angle of the major dynamical axis of the galaxy. Knowledge of the velocity held in spiral galaxies makes it possible to better understand galactic structures and mechanisms for their formation.