GRAVITATIONAL ASYMMETRIES IN GASEOUS DISKS

We report preliminary results of self-gravitating simulations of spira l galaxies modeled by two components, stellar and gaseous disks. One o f the objectives of this work is to study asymmetries in the distribut ion of the gas, features observed for a number of spiral galaxies. The gas disk is simulated by the Beam-Scheme method, where the gas is con sidered as a fluid. The results suggest that very concentrated galacti c disks can be unstable to the one-armed (m=1) spiral perturbation, wh ich may explain the asymmetric patterns observed in isolated galaxies.