2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/4650Gas and stars in spiral galaxies are modelled with the DUAL code, using hydrodynamic and N-body techniques. The simulations reveal morphological differences mirroring the dual morphologies seen in B and K' band observations of many spiral galaxies. In particular, the gaseous images are more flocculent with lower pitch angles than the stellar images, and the stellar arm-interarm contrast correlates with the degree of morphological decoupling.4 pages, 4 figures, to appear in Disk of Galaxies: Kinematics, Dynamics and Perturbations, ASP Conf. Series, 2002Astrophysicstext