1995A&A...299..371S

We present CO(1-0) and CO(2-1) observations of the barred late-type galaxy NGC 7479 with 23"and 12"resolution carried out whith the IRAM 30m telescope. The molecular component appears to be confined inside the strong stellar bar, and in particular, in the central spot. This concentration could have triggered the present central starburst, detected in the IRAS survey. We also present numerical simulations of the molecular interstellar gas based on a model of cloud inelastic collisions. The location of the main resonances has been determined by this model, under the hypothesis of the existence of a well defined wave mode, since this galaxy is strongly barred and its arms seem in exact prolongation of the bar. The best fit of the simulations is obtained for a pattern speed of {OMEGA}_p=30km/s/kpc wich places corotation at a radius R_CR∼9 kpc, in the outer disc. In our simulations a narrow gaseous bar appears aligned with the stellar bar, which corresponds to our CO observations. The bar and spiral structure are both inside corotation and there is no Inner Lindblad Resonance (ILR). The bar length corresponds to the exponential disc scale length. We compare our results with recent N-body simulations, describing bar and spiral evolution in function of Hubble type (Combes & Elmegreen 1993A&A...271..391C). In late-type galaxies, the bar end can be well inside its corotation. The results obtained in both the observations and the simulations of NGC 7479 seem to be in excellent agreement with these predictions.