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 field (i.e., the three velocity components) in the gaseous disks of spiral galaxies from observed radial velocities. The method is based on Fouri er analysis of the observed velocity field and interpretation of the r esulting Fourier harmonics in the framework of a model accounting for motion in the spiral arms. The model is based on the concept of galact ic spirals as density waves, The proposed method can be used to (1) fi nd noncircular velocities associated with spiral-vortex structure; (2) find fundamental parameters for this structure, such as the angular r otational velocity, the corotation radius, and the location of giant a nticyclones; (3) refine the rotation curves of galaxies by taking into account noncircular velocities in spiral density waves, which leads t o a more precise determination of the mass distribution in the galaxie s; and (4) refine parameters determining the galactic plane: inclinati on angle, location of the center of rotation, and the position angle o f the major dynamical axis of the galaxy. Knowledge of the velocity fi eld in spiral galaxies makes it possible to better understand galactic structures and mechanisms for their formation.