Magnetic fields in barred galaxies - II. Dynamo models

We study the generation and maintenance of large-scale magnetic fields in b arred galaxies. We take a velocity field (with strong noncircular component s) from a published gas dynamical simulation of Athanassoula (1992), and us e this as input to a galactic dynamo calculation. Our work is largely motiv ated by recent high quality VLA radio observations of the barred galaxy NGC 1097, and we compare our results in detail with the regular magnetic field s deduced from these observations. We are able to reproduce most of the con spicuous large-scale features of the observed regular field, including the field structure in the central regions, by using a simple mean-field dynamo model in which the intensity of interstellar turbulence (more precisely, t he turbulent diffusivity) is enhanced by a factor of 2-6 in the dust lanes and near the circumnuclear ring. We argue that magnetic fields can be dynam ically important, and therefore should be included in models of gas ow in b arred galaxies.